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... Some of this may become available in recipient ecosystems but some will not. Adsorbed P is much more likely to desorb and become biologically available in estuaries and coastal marine ecosystems than in lakes, due to higher ionic strength and more ions competing for sorption sites as salinity increases (Froelich 1988;Howarth et al. 1995). ...
... Part of the answer undoubtedly lies in the differences between the relative influence of the biogeochemical processes that occur within coastal ecosystems compared to lakes. These differences include a lack of planktonic N fixation in saline estuaries Marino et al. 2002;Marino and Howarth 2016) and the desorption of P from particles as salinity increases in an estuary (Froelich 1988;Howarth et al. 1995). Another important part of the answer, although one less discussed in the literature, is the N:P ratio of external inputs to the ecosystem: many estuaries and other coastal marine systems receive a significant portion of their nutrient inputs from ocean sources, not just from their watersheds. ...
... nitrite and SRP. Further, the sediments on continental shelves are the major site both for burial of P (Ruttenberg and Berner 1993;Howarth et al. 1995) and of denitrification (Falkowski 1997;Galloway et al. 2004) globally in the world's oceans. Denitrification can have a substantial influence on the inorganic N availability in regions where the continental shelf is wide. ...
Whether net primary productivity in an aquatic ecosystem is limited by nitrogen (N), limited by phosphorus (P), or co-limited by N & P is determined by the relative supply of N and P to phytoplankton compared to their elemental requirements for primary production, often characterized by the “Redfield” ratio. The supply of these essential nutrients is affected by both external inputs and biogeochemical processes within the ecosystem. In this paper, we examine external sources of nutrients to aquatic systems and how the balance of N to P inputs influences nutrient limitation. For ocean subtropical gyres, a relatively balanced input of N and P relative to the Redfield ratio from deep ocean sources often leads to near co-limitation by N and P. For lakes, the external nutrient inputs come largely from watershed sources, and we demonstrate that on average the N:P ratio for these inputs across the United States is well above that needed by phytoplankton, which may contribute to P limitation in those lake that experience this average nutrient loading. Watershed inputs are also important for estuaries and coastal marine ecosystems, but ocean sources of nutrients are also significant contributors to overall nutrient loads. The ocean-nutrient sources of N and P are very often at or below the Redfield ratio of 16:1 molar, and can be substantially so, particularly in areas where the continental shelf is wide. This large input of coastal ocean nutrients with a low N:P ratio is one factor that may make N limitation more likely in many coastal marine ecosystems than in lakes.
... The concentration of dissolved inorganic phosphorus in the overlying water column of an estuary depends upon the ability of the surficial sediments to retain or release dissolved inorganic phosphate (DIP) [15]. Studies of phosphorus dynamics of the Cochin estuary are mainly restricted to dissolved inorganic phosphate (DIP) in water and total phosphorus content in sediments [1,[16][17][18][19]. However, total phosphorus content in sediments does not provide an accurate assessment of phosphorus cycling or its bioavailability in the estuarine environment as it depends on speciation [20][21][22]. ...
... The water column was found to be strongly stratified during the monsoon but only a weak stratification was found during the premonsoon. During the monsoon, at the neap1 and spring II phases of tide the surface and bottom waters was found to be low saline due to weak saline water incursion (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) during the high tide ( Figure 3a). During the monsoon, at the neap II and spring 1 phase of tide a dominant fresh water inflow is noted on surface waters of the estuary as indicated by the zero salinity values towards the seaward end ( Figure 3a). ...
Here we studied total phosphorus and its fractions in sediments from the Cochin backwaters along with dissolved inorganic phosphate, tidal currents, pH, and salinity during the monsoon and pre-monsoon periods. During the monsoon, sediments function as a sink for phosphate derived from land-based pollutant sources, whereas, during the pre-monsoon, sediment re-suspension provides a source of phosphate to the overlying water column, both with the capacity to alter eutrophication events. The heavy river runoff during the monsoon lowers the pH and salinity of the water column, thereby enhancing adsorption of phosphorus from water to sediments. In contrast, seawater incursion during the pre-monsoon increases the pH and salinity of the water column to enhance the desorption of phosphorus from sediments to the water. Iron-bound inorganic (0.48-0.78 mg g-1) and organic phosphorus (1.04-1.30 mg g-1), calcium-bound inorganic (0.78-1.56 mg g-1) and organic phosphorus (1.13-1.83 mg g-1), acid-soluble organic phosphorus (0.07-0.21 mg g-1), and alkali-soluble organic phosphorus (0.22-0.70 mg g-1), were detected in sediments. The main sedimentary phosphorus pool was a calcium-and iron-bound phosphorus compound. Precipitation/flocculation of dissolved inorganic phosphate within the estuarine salinity gradients (~15-30), followed by its adsorption/desorption with iron oxy-hydroxides and calcium carbonate minerals that settle in the bottom sediments govern the phosphorus biogeochemistry of the Cochin backwaters.
... For example, nutrients in nearshore systems are important in controlling densities and toxicity of micro-and macro-algae and, along with temperature, can be significant drivers of toxic and non-toxic algal blooms (Anderson et al., 2002;Gilbert et al., 2018;Gobler et al., 2016). Although these algal blooms can be naturally occurring, human activities have substantially increased nutrient inputs to coastal and estuarine waters since the Industrial and Agriculture Revolutions (from increased use of chemical fertilizer; Boyer and Howarth, 2008;Howarth et al., 1995), resulting in nutrient pollution and a global increase in eutrophication (Nixon, 1995;Rabalais, 2002). ...
... It is also important to note that nitrogen is not the only nutrient that can accumulate in nearshore systems and bivalves. Although nitrogen is considered the primary nutrient involved in coastal and estuarine eutrophication (Gobler et al., 2016), phosphorous can also accumulate in these systems (Howarth et al., 1995). As such, future studies would benefit from understanding the phosphorus removal potential of shellfish aquaculture in the region. ...
Bivalve farming can contribute to nutrient removal in coastal and estuarine systems, as bivalves directly incorporate nutrients into their tissues and shells. We conducted a meta-analysis to compare the nitrogen removal potential (NRP; i.e., percentage of nitrogen in tissues and shells) of mussels, Mytilus edulis, and oysters, Crassostrea virginica. We then used species-specific NRPs to determine and compare the total and per-hectare NRPs for four shellfish aquaculture methods used in two Atlantic Canadian provinces – New Brunswick (NB) and Prince Edward Island (PEI) – based on current harvest biomasses. Finally, we determined the contribution of current shellfish farming to nitrogen load mitigation for a subset of bays in NB and PEI. Results revealed that on a per-weight basis, NRP was similar for the tissues of mussels and oysters, while mussel shells had a significantly higher percentage of nitrogen than oyster shells. Collectively, shellfish harvesting has the capacity to remove a mean annual total of 99088 kg and 204571 kg of nitrogen from NB and PEI, respectively. Given current harvesting practices for four culture methods employed in the region, suspended mussel culture provides the greatest NRP per hectare of farm area, followed in sequence by suspended mussel and oyster mixed culture, suspended oyster culture, and bottom oyster culture. Preliminary analysis suggested that harvests in the region typically remove
... Few recent studies exist on the total phosphorus flux from the world's rivers. Mayorga et al. (2010) found a total yearly phosphorus flux of 9 Tg, while other studies found higher yearly estimates (11 Tg by Seitzinger et al. (2005), 20 Tg by Howarth et al. (1995)). The lateral fluxes of total phosphorus found by Quinton et al. (2010) are larger than the estimated phosphorus export from the world's rivers to the ocean. ...
... This indicates the importance of a global assessment of the effects of soil erosion on the nutrient cycles. (Howarth et al., 1995) The total flux of nitrogen and phosphorus to the global ocean is estimated at respectively 45 to 60 and 9 to 20 Tg year −1 (Table 4.6 and 4.7), of which respectively about 14 and 7 Tg year −1 is in the form of particulate nitrogen (P N ) and (P P ) Mayorga et al. (2010). We expect that soil erosion will lead mostly to P N and P P , as in the case of SOC erosion. ...
... Phosphorus is primarily transported to coastal marine areas by rivers and, on a global scale, this source of P have at least doubled due to fertilisation and other anthropogenic activities (Howarth et al. 1995). The increased input of P has caused eutrophication (cf., Nixon 1995) in many lakes and coastal marine areas (Correll 1998). ...
... Conversely in oxic sediments, low or even negative (i.e., sedimentary uptake of DIP) fluxes that were not correlated to DIC production rates indicate very efficient trapping mechanisms of DIP under oxic conditions. Pore water profiles of DIP, dissolved iron (Fe), and dissolved manganese (Mn) indicate that Fe (oxy)hydroxide and Mn-Fe oxide/hydroxide particles in the surficial oxidised sediment may act as a barrier that diminishes the flux of DIP to the overlying bottom water (e.g., Sundby et al. 1992;Howarth et al. 1995;Yao & Millero 1996;Dellwig et al. 2010). ...
This Thesis focuses on the exchange of phosphorus (P) across the sediment–water interface in the Baltic Sea proper, with particular attention to the influence of bioturbating macrofauna and benthic redox conditions. Benthic P fluxes have major influence on P availability in the water column, which in turn regulates growth conditions for dinitrogen fixating cyanobacteria in the Baltic proper. Presently, a very large area of bottom sediment is overlain by oxygen depleted bottom water and is therefore devoid of aerobic organisms.
In paper I, anoxic sediment from the Western Gotland Basin was oxygenated and exposed to bioturbation by three macrofauna species in a laboratory experiment. The experimental design allowed for detailed studies of how bioturbating animals influence the P fluxes on a species-specific level. All species (Monoporeia affinis, Mysis mixta, and Macoma balthica) mobilised dissolved organic P from the bottom sediment to the supernatant water. Also, particulate P was released by the two former species. None of these P fractions showed any mobility in control sections of the aquarium system. These animal-dependent P fluxes are a previously largely overlooked but potentially significant source of bioavailable P in coastal marine areas, such as the Baltic Sea.
In paper II, we estimate a contemporary reflux of 146 kton dissolved inorganic P (DIP) from bottom sediments in the Baltic proper. This estimate is based on data from a large number of in situ benthic flux measurements using benthic chamber landers along a depth gradient in the Eastern Gotland Basin. DIP effluxes increased with increasing water depth, and decreasing bottom water oxygen concentrations. Bottom water anoxia was identified as a major driver for the mobilisation of DIP from bottom sediments. During such conditions, the DIP efflux was well correlated to carbon oxidation rate, while on oxic bottoms DIP fluxes were low irrespectively of the carbon oxidation rate. Our data support the hypothesis of a positive feedback loop of self-amplifying eutrophication in the Baltic Sea. Thus, both nutrient emission cuts and active mitigation actions to strengthen sedimentary P sinks are warranted for effective remediation of eutrophication in the Baltic Sea.
... Phosphorus (P) is a key element that limits marine primary productivity in short and long time scales (Holland, 1978;Howarth et al., 1995;Tyrrell, 1999). The major source of P to the oceans is fluvial input which brings weathered constituents. ...
... Climate change is poised to exacerbate impacts of coastal eutrophication in the northern Gulf of Mexico (Laurent et al., 2018). Coastal eutrophication is often accompanied by hypoxia (Howarth, 1995;Nixon et al., 1995;Vitousek et al., 1997;Caraco and Cole, 1999;Bennett et al., 2001). The increase in frequency of hypoxia and anoxia formations in shallow, coastal and estuarine areas is highly likely a result of human activities (Diaz et al., 1995). ...
The latest technological advancements in the development and production of sensors have led to their increased usage in marine science, thus expanding data volume and rates within the field. The extensive data collection efforts to monitor and maintain the health of marine environments supports the efforts in data driven learning, which can help policy makers in making effective decisions. Machine learning techniques show a lot of promise for improving the quality and scope of marine research by detecting implicit patterns and hidden trends, especially in big datasets that are difficult to analyze with traditional methods. Machine learning is extensively used on marine science data collected in various regions, but it has not been applied in a significant way to data generated in the Gulf of Mexico (GOM). Machine learning methods using ocean science data are showing encouraging results and thus are drawing interest from data science researchers and marine scientists to further the research. The purpose of this paper is to review the existing approaches in studying GOM data, the state of the art in machine learning techniques as applied to the GOM, and propose solutions to GOM data problems. We review several issues faced by marine environments in GOM in addition to climate change and its effects. We also present machine learning techniques and methods used elsewhere to address similar problems and propose applications to problems in the GOM. We find that Harmful Algal Blooms (HABs), hypoxia, and sea-level rises have not received as much attention as other climate change problems and within the machine learning literature, the impacts on estuaries and coastal systems, as well as oyster mortality (also major problems for the GOM) have been understudied – we identify those as important areas for improvement. We anticipate this manuscript will act as a baseline for data science researchers and marine scientists to solve problems in the GOM collaboratively and/or independently.
... However, these riverine loads were substantially reduced, achieving an average of 4.8 kg ha −1 yr −1 in recent N budgets developed for the 2013-2015 time period, with one exception (i.e., the Ten Mile River; Narragansett Bay Estuary Program, 2017; Krumholz, 2012). Export from pristine temperate zones prior to human disturbances is estimated to have been on the order of 1.3 kg N ha −1 yr −1 (Howarth et al., 1995(Howarth et al., , 1996. Most Narragansett Bay rivers are moving toward this pristine condition, whereas the Pawcatuck River has shown an increase in N load over time. ...
Coastal waters globally are increasingly impacted due to the anthropogenic loading of nitrogen (N) from the watershed. To assess dominant sources contributing to the eutrophication of the Little Narragansett Bay estuary in New England, we carried out an annual study of N loading from the Pawcatuck River. We conducted weekly monitoring of nutrients and nitrate (NO3-) isotope ratios (15N / 14N, 18O / 16O, and 17O / 16O) at the mouth of the river and from the larger of two wastewater treatment facilities (WWTFs) along the estuary, as well as seasonal along-river surveys. Our observations reveal a direct relationship between N loading and the magnitude of river discharge and a consequent seasonality to N loading into the estuary – rendering loading from the WWTFs and from an industrial site more important at lower river flows during warmer months, comprising ∼ 23 % and ∼ 18 % of N loading, respectively. Riverine nutrients derived predominantly from deeper groundwater and the industrial point source upriver in summer and from shallower groundwater and surface flow during colder months – wherein NO3- associated with deeper groundwater had higher 15N / 14N ratios than shallower groundwater. Corresponding NO3- 18O / 16O ratios were lower during the warm season, due to increased biological cycling in-river. Uncycled atmospheric NO3-, detected from its unique mass-independent NO3- 17O / 16O vs. 18O / 16O fractionation, accounted for
... As expected, both DIN and DIP levels increased during period of seasonal precipitations as runoffs from adjacent areas tend to increase, thereby accounting for temporal fluctuations in nutrient profiles (Fig. 3). In estuaries like the present sampling area with high SPM load, a great deal of P remains attached to these particles that tend to desorb (release) from adsorption sites as cationic competition increases with increased salinity influences (Fig. 4) due to marine water intrusions (Froelich 1988;Howarth et al. 1995Howarth et al. , 2011Nemery and Granier 2007). ...
The Bhagirathi–Hooghly estuary represents one of the most populated estuaries in the Indian subcontinent with dense settlements along its course. The concomitant high anthropogenic influences and enhancement of nutrient load due to uncontrolled discharges from non-point source in monsoon play important role in habitat variability and consequential changes in the water quality of the estuary. Even though such nutrient loadings are expected to cause significant changes in the ecosystem functioning, a documentation of the habitat heterogeneity has largely remained unavailable from this important yet unmonitored estuary. Thus, the present work aims at assessment of water quality and trophic status of the habitat by application of a combination of abiotic and phytoplankton-specific indices as recommended by different international and national authorities. Results suggest that water quality deteriorated during periods of seasonal precipitation due to enhanced nutrient loadings that culminated in altering the trophic status of habitat. Comparisons with regard to international standards further corroborated the influence of seasonal precipitation on water quality and trophic status of the habitat. Phytoplankton functional groups largely reflected the changing nature of the habitat well, with dominance of those taxa that are more persistent under warm, nutrient replete shallow euphotic depths of the habitat. These findings further suggest that it is essential to regularly monitor the health of this estuarine ecosystem to as to sustain the different life forms that will be essential for the livelihood of people in this area.
... The runoff and leaching of the excess nutrients from agricultural soils, applied in form of fertilizer or animal manure, accounts for 82 -84 % nitrogen and phosphorous pollution of surface and subsurface water bodies [2]. According to an estimate, nitrogen export from agricultural ecosystems to waterbodies may range from 10 to 40% of fertilizer input for loamy and clayey soils to 25 -80 % for sandy soils [3]. According to the Georgia Watershed Agricultural Non-Point Source Pollution Assessment, approximately 39 % of phosphorous applied to land in form of animal manure could potentially be leaching into the State's waterways [4]. ...
This study investigated the phosphorus adsorption behaviors of pristine and MgO modified biochars produced from woody biomass precursors (having different anatomical characteristics and similar specific gravities) and their MgCl2 impregnated counterparts. The biomass precursors were Longleaf pine wood shavings, Red Oak and Hard Maple sawdusts. The microstructural, physicochemical, textural, and phosphorus adsorption characteristics of the pristine and MgO modified biochars were examined. The percent yields (45.01 – 56.35%) of the MgO modified biochars were higher than the percent yields (29.29 – 30.08%) of the pristine biochars, mainly due to the presence of added MgO. The pH of all the biochars showed that they were alkaline in nature. The cation exchange capacities of the pristine and MgO modified biochars were 1.62 - 3.20 cmol/kg and 84.81 - 111.12 cmol/kg, respectively. The specific surface areas of the pristine and MgO modified biochars were 0.26 - 8.82 m2/g and 22.02 - 28.07 m2/g, respectively. The phosphorus adsorption capacities of the pristine and MgO modified biochars were 1.88 – 2.78 mg/g and 28.20 – 29.22 mg/g, respectively. The pristine hardwood derived biochars (Hard Maple and Red Oak) showed better phosphorous adsorption capacities than the pristine softwood derived biochar (Longleaf Pine), and the MgO modified biochars showed 11 times higher phosphorus adsorption capacities than the pristine biochars.
... O sedimento dos estuários também pode atuar como fonte ou sorvedouro de fósforo, potencializando ou controlando o processo de eutrofização (KNOPPERS et al., 2004;PRATSKA et al., 1998). Nas zonas mortas o fósforo é liberado do sedimento para a coluna de água, devido a dessorção das ligações iônicas (HOWARTH et al., 1995;RABALAIS et al., 2010). ...
Este estudo teve como objetivo investigar a dinâmica biogeoquímica e o estado trófico do estuário-lagunar do Rio da Madre (ELRM) em relação aos impactos antrópicos e às características ambientais. A bacia hidrográfica do ELRM drena uma grande região ocupada pela rizicultura intensiva e, em menor escala, pela urbanização. O estuário foi setorizado em quatro regiões de acordo com o gradiente salino: laguna da Guarda do Embaú, lagoa do Ribeirão, estuário médio e estuário interno. Em cada região, dois pontos amostrais foram selecionados para coleta de água (nutrientes e biomassa fitoplanctônica), sedimento (teor de matéria orgânica) e medidas in situ da profundidade local, zona eufótica, turbidez, pH, salinidade, temperatura e oxigênio dissolvido. O modelo biogeoquímico LOICZ foi aplicado para quantificar as trocas de água, sal e nutrientes que ocorrem entre a bacia hidrográfica, o estuário e o mar adjacente. O índice trófico TRIX foi utilizado para caracterizar o estado trófico do sistema. Períodos de intensa precipitação “lavaram” o estuário, tornando a coluna de água homogênea e mesotrófica. Já durante a passagem de ventos do quadrante sul foi observado coluna de água estratificada e eutrófica, devido ao aumento do tempo de residência da água no sistema. O estuário interno, adjacente à rizicultura, apresentou condições hipóxicas e/ou anóxicas na água de fundo, além das maiores concentrações de matéria orgânica, ortofosfato e N-amoniacal. Estas águas se caracterizaram como sítio de mineralização da matéria orgânica autóctone e alóctone, principalmente em períodos de estratificação física da coluna de água, aumentando o aporte de nutrientes para o sistema. No entanto, a produção primária, a denitrificação e o tamponamento do fósforo das regiões adjacentes controlaram a concentração dos nutrientes. O ELRM apresentou metabolismo heterotrófico em 72% das amostragens, porém, durante os períodos de autotrofia, a produção algal foi característica de sistema hipertrófico. Os dados deste estudo indicaram que o ELRM está em processo de eutrofização e que a rizicultura e urbanização estão contribuindo diretamente neste processo. O baixo tempo de residência da água e as altas taxas de denitrificação se apresentaram como mecanismos essenciais para a manutenção da qualidade ambiental deste ecossistema, favorecendo a exportação de nutrientes para os compartimentos adjacentes e controlando processo de eutrofização.
... The TOC and TN content in marine sediment is controlled by numerous factors such as the grain size, productivity and oxygen content of the waters, water depth, intensity of monsoons, bacterial degradation, and sedimentation rates 91,76,92,93,77,94,95 . The TOC and TN content in the sediment increased with increasing distance from the coast. ...
The sediment cores collected along three transects off the Mahanadi, Godavari and Krishna rivers were analyzed for spatial and temporal variations in grain size, clay minerals, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), calcium carbonate, and selected metals (Al, Fe, Ti, Mn, Zn) to understand the provenance of sediments and the role of monsoons and dissolved oxygen in the preservation of organic elements and metals in recent past. Illite was the dominant mineral off Mahanadi and smectite off Godavari and Krishna that indicated their different sources, viz., felsic and mafic rocks, respectively. The high Fe/Al and Ti/Al content in shallow areas off Godavari and Krishna may have been added from the leaching of Red Beds and mafic rocks respectively. The TOC/TN molar ratio was above 8.00 in most samples that indicated the supply of organic matter from terrestrial sources. The sediment with less carbonate and organic matter revealed low biological productivity in the study area. The relatively higher sand, elevated S/I+C ratio and metal content in the surface sediments and the lower section in majority of the cores indicated intensified rainfall and high runoff that brought increased oxygenated fresh water along with the higher metal influx. The reduced concentration of Mn/Al along with low S/I+C ratio and higher TOC and TN values in the 15 cm to 5 cm section in the cores off Godavari revealed weak rainfall which turned the water anoxic, as the available oxygen was consumed by the planktons. Under intensified OMZ, Mn/Al got depleted in reducing conditions and TOC, TN was better preserved.
... En las últimas décadas, el aporte de nutrientes (nitrógeno y fósforo) al medio acuático se ha incrementado a nivel mundial, lo cual se asocia al aumento de actividades antropogénicas, como la agricultura, los procesos industriales intenintroducción constante de nutrientes y materia orgánica a los diferentes medios acuáticos y, en consecuencia, favorece las condiciones para la proliferación de las algas en áreas de mayor extensión y con mayor frecuencia (Nixon, 1995;Howarth et al., 1995;Vitousek et al., 1997;Caraco y Cole, 1999;Bennett et al., 2001). FA) son eventos recurrentes y han ocasionado alteraciones en los ecosistemas marinos costeros e impactos negativos en actividades productivas como la pesca, la acuicultura, la salud humana e indirectamente el turismo. ...
At present, the remote sensing of ocean color (NASA), has become a tool with high potential for use in activities and utilization of the ocean: primary productivity, resource management, distribution and abundance of birds, identification of fishing. Also allows addressing many problems derived from anthropogenic activities- the oil exploration, for examples-, the eutrophication and hypoxia, and the monitoring of algal blooms.
... Howarth et al. (2002), for example, showed that the amount of dissolved inorganic nitrogen transported from rivers to coastal ocean waters nearly doubled between 1961 (3.0 Tg-N year À1 ) and 1997 (5.0 Tg-N year À1 ), reflecting increased fertilizer use, fossil fuel combustion, and nitrogen fixation in agricultural systems (see Galloway et al., 2002). Howarth et al. (1995) also revealed that phosphorus loads through the river-estuaryocean continuum have increased markedly from historic levels of $8 Â 10 6 mt (metric tons) year À1 to $22 Â 10 6 mt year À1 . ...
... Howarth et al. (2002), for example, showed that the amount of dissolved inorganic nitrogen transported from rivers to coastal ocean waters nearly doubled between 1961 (3.0 Tg-N year À1 ) and 1997 (5.0 Tg-N year À1 ), reflecting increased fertilizer use, fossil fuel combustion, and nitrogen fixation in agricultural systems (see Galloway et al., 2002). Howarth et al. (1995) also revealed that phosphorus loads through the river-estuaryocean continuum have increased markedly from historic levels of $8 Â 10 6 mt (metric tons) year À1 to $22 Â 10 6 mt year À1 . ...
This contribution has focused on the sediment composition of estuaries. It has shown that all estuaries share some common features in relation to the sediment composition along and across the estuarine waterbody. However, this composition will depend on the geographical location of the estuary, on the estuary’s origin, on the relative contribution of different physical processes and sediment sources, and on the landscape characteristics.
... Phosphorus (P) is an essential element for marine primary productivity and also acts as a limiting nutrient over geological time scale ( Holland, 1978;Broecker and Peng, 1982;Howarth et al., 1995;Tyrrell, 1999). The major sources of P in the ocean are river input, atmospheric deposition and hydrothermal input (e.g., Paytan and Mclaughlin, 2007), while the ultimate sink of P in the ocean is burial within the sediment ( Ruttenberg and Berner, 1993). ...
Results of a study on phosphorus (P) cycling in the Eastern Arabian Sea provides convincing evidence of present-day phosphogenesis in the study area. This finding contrasts with previous reports of the occurrence of only old phosphorites along the Indian margin. Extensive benthic P regeneration is observed in the sediments that are deposited on topographic highs in the western Indian continental margin, which is impinged by a perennial oxygen minimum zone (OMZ). The phosphate flux from the sediments ranged between 1.1 and 22 mmol m-2 yr-1. Among the P reservoirs, biogenic P (Pbio) is the major pool of P within the upper 30 cm of sediment. P released from organic matter decomposition and fish debris dissolution mainly controls benthic P regeneration while the role of redox cycling of iron is weak. The change in authigenic P (Pauth) with depth in the sediment and concomitant decrease in porewater dissolved inorganic phosphate (DIP), solid phase Pbio and organic P (Porg) content collectively indicate the transformation of P from labile phases to an authigenic phase. Molar Corg/Porg and Corg/Preactive ratios also support the notion of ongoing phosphogenesis in the area. The content of carbonate fluroapatite (CFA) is elevated especially in one of the three study sites as a result of in-situ precipitation and a contribution from eolian and water column authigenesis. The estimated burial efficiency of P at the sediment-water interface at two locations is only about 2%, which is much less than in the western Arabian Sea also indicating extensive P regeneration
... Phosphorus (P) is an essential nutrient for all living species and is believed to be the ultimate limiting nutrient for marine primary production on geological time scales (Howrath et al., 1995;Van Cappellen and Ingall, 1996;Tyrrell, 1999;Paytan and McLaughlin, 2007). Continental weathering processes mainly control the natural supply of P into the marine environment (Filippelli, 2002;Paytan and McLaughlin, 2007). ...
The seasonal upwelling along the southeastern Arabian Sea (SEAS) brings cold, nutrient-rich low oxygen subsurface water to the continental shelf. The subsurface oxygen deficiency due to upwelling is severe in some years, the intensity of which could profoundly influence the nutrient cycling along the SEAS. Herein, we studied the effect of seasonal anoxia on fractionation of phosphorus during the peak upwelling period of August 2013. Abundance of five fractions of phosphorus (P), namely exchangeable or loosely sorbed P (Pads), iron-bound P (PFe), authigenic P (Paut), detrital apatite plus other inorganic P (Pdet) and organic P (Porg),in surface sediments of SEAS shelf has been studied using a sequential extraction procedure (SEDEX) to examine their distributions and sources. Total P (TP) concentrations ranged from 209 to 1081 µg g-1 with an average of 508±256 µgg-1.Among the five P fractions, the authigenic P was the dominant species, representing about 60% of TP. The relative abundance of P fractions was in the order: Paut>Pdet>Porg>PFe> Pads. Multivariate analyses revealed that the P fractions were primarily associated with the organic constituents and fine sediments. The hypoxic bottom condition associated with summer monsoon upwelling significantly reduced the concentrations of PFe, Pads and Porg in the surface sediments. The enhanced release of organic bound and iron oxides bound P under low oxygen condition was evident from the enhanced C/P and N/P ratios and lower C/N ratio in the sediments. The intense biomineralization of organic matter and reduction of Fe-Mn oxides due to the periodic anoxia resulted in the transformation of their associated P fractions and enhanced accumulation as authigenic calcium phosphate mineral.
... A satisfying similarity between the magnitude of net areal production in the open ocean with the verifiable rates of invasion of carbon dioxide from the atmosphere [26] notwithstanding, higher concentrations of inorganic carbon and faster rates of biomass assembly are achieved in, for example, low-latitude shelf waters and in shallow lakes, generally without obvious symptoms of carbon limitation (high pH, carbonate precipitation) in most instances. Large fluxes of dissolved carbon dioxide, as with substantial amounts of other nutrients, are delivered in the fluvial runoff, emanating from terrestrial sources [27]. Organic sources of carbon are also prominent in the function of aquatic ecosystems. ...
The term ‘pelagic zone’ refers essentially to the open ocean, beyond the continental shelves. However, ‘the pelagic’ is understood by freshwater ecologists to mean simply ‘the open water’ of large lakes and reservoirs. In either instance, the notion of a liquid environment, remote from the shores and bottom of the containing basin, is clear. In extent, the marine pelagic is, by far, the greatest of the world's major ecosystems, covering some 361 × 10⁶ km² (or 71% of the planet's surface) and accommodating an estimated volume of 1.35 × 10⁹ km³. In contrast, the aggregate volume of the world's lakes and rivers is a relatively modest 225 × 10³ km³.
... Sin embargo, en las décadas posteriores, esta hipótesis se vio cuestionada principalmente en estuarios y ecosistemas oceánicos costeros (Howarth and Marino 2006). Esto debido principalmente al hecho de que el incremento continuo de fósforo a los ecosistemas acuáticos puede producir un cambio hacia la limitación por nitrógeno (Howarth, Jensen et al. 1995). En la actualidad, el consenso general, aunque no libre de debate (Schindler, Hecky et al. 2008;Bryhn and Hakanson 2009;Conley, Paerl et al. 2009;Jacoby and Frazer 2009;Schelske 2009;Schindler and Hecky 2009), es que el nitrógeno también juega un rol importante como factor limitante en el desarrollo de la productividad primaria en determinados ecosistemas acuáticos (Howarth and Marino 2006). ...
... Available P in the biosphere has also increased in the last 50 years, largely as a result of P applications to agricultural lands. P flux to coastal oceans has nearly tripled, from 8 Â 10 6 Mg year À1 to the current rate of 22 Â 10 6 Mg year À1 (Howarth et al., 1995). Nutrient enrichment has complex, often detrimental eVects in natural ecosystems (Carpenter and Cottingham, 1997;Galloway, 2000;Vitousek et al., 1997). ...
The management of nutrients is fundamental to agricultural productivity and viable rural livelihoods. Farmers have the dual goals of supporting crop and animal growth, while minimizing losses to the environment. Nutrient availability is a function of management practices and inherent characteristics of the environment (i.e., climate, soil type), and the organisms in that environment. In this chapter we explore how the application of ecological principles will provide managers with tools for developing coherent nutrient management strategies that optimize the complex processes governing nutrient cycling in agroecosystems. Sustainable management requires close attention to internal nutrient cycling, through building labile/available pools AND nutrient pools that are more easily retained in the soil. Strategic choices are required in orchestrating the full suite of management decisions that contribute to effective nutrient management, including decisions such as which fertility sources to use, and how much to apply in a given field, how to use rotation and intercropping in concert with these sources, which crop genotypes to grow, and how to best use interventions such as tillage or fire. Participatory techniques for assessing current nutrient management practices and developing innovative systems are invaluable in developing ecologically based nutrient management schemes.
... A satisfying similarity between the magnitude of net areal production in the open ocean with the verifiable rates of invasion of carbon dioxide from the atmosphere [26] notwithstanding, higher concentrations of inorganic carbon and faster rates of biomass assembly are achieved in, for example, low-latitude shelf waters and in shallow lakes, generally without obvious symptoms of carbon limitation (high pH, carbonate precipitation) in most instances. Large fluxes of dissolved carbon dioxide, as with substantial amounts of other nutrients, are delivered in the fluvial runoff, emanating from terrestrial sources [27]. Organic sources of carbon are also prominent in the function of aquatic ecosystems. ...
... This drainage can reduce the pH and enhance the CO 2 concentration estuaries, aggravating the global impacts (NORIEGA et al., 2012). Thus, drainage basins and associated estuaries represent important regions for evaluating interactions between local and global stressors (HOWARTH et al., 1995; CANALS; BALLESTEROS, 1996), including variations in rainfall patterns. factors studied independently; (2) additive: factors have a each factor when acting in isolation; and (4) antagonistic: the factors have a negative interaction, one neutralizing the other. ...
Rhodolith beds are important marine benthic ecosystems, representing oases of high biodiversity among sedimentary seabed environments. They are found frequently and abundantly, acting as major carbonate ’factories’ and playing a key role in the biogeochemical cycling of carbonates in the South Atlantic. Rhodoliths are under threat due to global change (mainly related to ocean acidification and global warming) and local stressors, such as fishing and coastal run-off. Here, we review different aspects of the biology of these organisms, highlighting the predicted effects of global change, considering the additional impact of local stressors. Ocean acidification (OA) represents a particular threat that can reduce calcification or even promote
the decalcification of these bioengineers, thus increasing the ecophysiological imbalance between calcareous and fleshy algae. OA should be considered, but this together with extreme events such as heat waves and storms, as main stressors of these ecosystems at the present time, will worsen in the future, especially if
possible interactions with local stressors like coastal pollution are taken into consideration. Thus, in Brazil there is a serious need for starting monitoring programs and promote innovative experimental infrastructure in order to improve our knowledge of these rich environments, optimize management efforts and enhance the needed conservation initiatives.
... This drainage can reduce the pH and enhance the CO 2 concentration even further, especially in anthropogenically influenced estuaries, aggravating the global impacts (NORIEGA et al., 2012). Thus, drainage basins and associated estuaries represent important regions for evaluating interactions between local and global stressors (HOWARTH et al., 1995; CANALS; BALLESTEROS, 1996), including variations in rainfall patterns. There are different ways in which global factors, such as temperature and acidification, can interact with local factors, such as nutrients: (1) isolated: the effect of each factor is not influenced by the effects produced by other factors studied independently; (2) additive: factors have a joint effect on the study object that is equal to the sum of the effects caused by each factor when tested in isolation; (3) synergy: the factors have a joint effect on the study object that is greater than the simple sum of the effects caused by each factor when acting in isolation; and (4) antagonistic: the factors have a negative interaction, one neutralizing the other. ...
Rhodolith beds are important marine benthic ecosystems, representing oases of high biodiversity among sedimentary seabed environments. They are found frequently and abundantly, acting as major carbonate ‘factories’ and playing a key role in the biogeochemical cycling of carbonates in the South Atlantic. Rhodoliths are under threat due to global change (mainly related to ocean acidification and global warming) and local stressors, such as fishing and coastal run-off. Here, we review different aspects of the biology of these organisms, highlighting the predicted effects of global change, considering the additional impact of local stressors. Ocean acidification (OA) represents a particular threat that can reduce calcification or even promote the decalcification of these bioengineers, thus increasing the eco-physiological imbalance between calcareous and fleshy algae. OA should be considered, but this together with extreme events such as heat waves and storms, as main stressors of these ecosystems at the present time, will worsen in the future, especially if possible interactions with local stressors like coastal pollution are taken into consideration. Thus, in Brazil there is a serious need for starting monitoring programs and promote innovative experimental infrastructure in order to improve our knowledge of these rich environments, optimize management efforts and enhance the needed conservation initiatives.
... Increasing population growth, intensified development, and expansion of agricultural activities (e.g. increasing use of industrially produced fertilizers), especially in the temperate zone, led to a twofold increase in the global flux of nitrogen (N; Galloway et al., 2004) and a two-to threefold greater phosphorus flux (P; Howarth et al., 1995) to coastal waters. This excess nutrient input to aquatic ecosystems (eutrophication) stimulates primary production and enhances the flow of organic water to the seafloor, fuelling microbial respiration and amplifying oxygen depletion (Rabalais et al., 2002). ...
... Phosphorus (P) is an essential nutrient for marine phytoplankton growth, and plays a significant role in the global biogeochemical cycling of biogenic elements in estuarine and coastal ecosystems (Howarth et al., 1995;Slomp et al., 2013;Meng et al., 2015). P is also critical to the global climate and environmental changes because of the relationship between atmospheric carbon dioxide and marine photosynthetic productivity (Broecker, 1982;Krom et al., 2004;Ni et al., 2015). ...
Surface and core sediments were collected off the eastern coast of Hainan Island (South China Sea), and a sequential extraction method (SEDEX) was used to separate and quantify five sedimentary phosphorus (P) reservoirs: exchangeable or loosely sorbed P (Ex-P), iron-bound P (Fe-P), authigenic P (Ca-P), detrital P (De-P) and organic P (OP). Total P (TP) in the surface and core sediments ranged from 7.96 to 22.34 µmol g−1, and was dominated by inorganic P (IP). De-P and Ca-P were the main chemical species of P in surface and core sediments. The distribution of the P species in surface and core sediments was governed by various factors, including terrigenous input, biological processes, Fe oxides/hydroxides, organic matter degradation, and sediment grain size. The organic carbon (OC)/OP ratio ranged from 37 to 293 (average, 107±58) in surface sediments, suggesting that the organic matter in sediments had been subject to degradation and comprised mostly refractory compounds. The OC/Preactive ratio (37–69) was relatively low in the core sediments, suggesting an excess of sedimentary reactive P compared with OC. The Fe/P ratio ranged from 2 to 19 in surface and core sediments, which indicates that the higher proportions of the crystalline phases occurred in estuarine areas relative to the offshore areas. The potential bioavailable P accounted for 20.3–54.2% of TP in the surface and core sediments.
... Sediment accumulation rates range from an order of a few millimetres per millennia in the vast areas of the deep oceans (Ku et al. 1968), up to one, or even around 10 millimetres annually in marine coastal and shelf areas (Chanton et al. 1983;Harnett et al. 1998;Ståhl et al. 2004a;Hille et al. 2006). Even though continental margin sediments cover less than one fifth of the world oceans (Walsh 1984), their high rates of accumulation and burial make them significant repositories or sinks in the global P (Howarth et al. 1995), N (Gruber 2008), andSi (De-Master 2002) cycles, while their role in the global C cycle is debated and remain unclear (e.g., Walsh 1981;Walsh 1984;Hedges & Keil 1995;Chen et al. 2013). ...
This thesis investigates how benthic fluxes of phosphorus (P), nitrogen (N), and silicon (Si) change upon oxygenation of anoxic soft bottoms in the brackish, eutrophicated Baltic Sea. Direct measurements in situ by benthic landers demonstrated that fluxes of dissolved inorganic P (DIP) from anoxic bottom sediments in the Eastern Gotland Basin are higher than previously thought (Paper I). It is argued that the benthic DIP flux has a much larger influence on the DIP inventory in the Baltic proper than the external sources. Similarly, benthic fluxes of DIP and dissolved inorganic N (DIN) from anoxic sediment in the coastal Kanholmsfjärden Basin, Stockholm archipelago, were sufficiently high to renew the pools of these nutrients below the upper mixed layer in roughly one year (Paper II).
A natural inflow of oxygen rich water into the deep, and previously long-term anoxic part of Kanholmsfjärden Basin, increased the P content in the sediment by 65% and lowered DIP and dissolved silica (DSi) concentrations in the pore water. These changes, as well as the large increases in benthic effluxes of these solutes following de-oxygenation of the bottom water, suggest that they are influenced similarly by changing oxygen conditions.
Experimental results in papers III and IV show that common benthic macrofauna species in the Baltic Sea can stimulate benthic release of DIN and DSi, as well as dissolved organic and particulate bound nutrients. Thus, if benthic oxygen conditions would improve in the Baltic, initial effects on benthic–pelagic nutrient coupling will change due to animal colonisation of currently azoic soft bottoms.
A new box corer was designed (Paper V) which can be used to obtain highly needed virtually undisturbed samples from soft bottom sediments – if lowered slowly and straight into the bottom strata – as demonstrated by in situ videography and turbidimetry. The commonly used USNEL box corer caused severe biasing during sediment collection.
Phosphorus (P), a crucial macronutrient, is essential in the maintenance of ecosystem productivity and the biogeochemical processes of other biogenic substances found in marine settings. The aim of the present study is to quantify the different geochemical fractions, bioavailability, and ecological risk of phosphorus in surface and core sediment of mangroves, Gulf of Kachchh (GoK). To better understand the P dynamics, sequential chemical extraction techniques were used to study sediment P pool distribution such as exchangeable P; Fe-bound P; authigenic P; detrital P; and organic P. The total sedimentary P ranged from 539.51 to 7217.24 mg/kg in pre-monsoon and 487.04 to 7180.26 mg/kg in post-monsoon, and was primarily composed of inorganic P. Authigenic P and Fe-bound P were the dominant fractions of P in surface and core sediments, exhibiting a significant long-term P reservoir. Sources such as riverine inputs, industrial and sewage discharge, aquaculture farms, and seaport operations all have an impact on the P dynamics in GoK. Furthermore, organic matter, pH, ORP, and diagenetic processes in sedimentary environment have influenced P retention and release. FeBD:Fe–P ratio indicates the presence of Fe matrices, having strong adsorption potential for P, with the availability of a surplus of Fe(III) (oxy)hydroxides serving as a significant P pool, governing the P dynamics. The P enrichment index (PEI) showed that sediments were highly impacted by anthropogenic P and could cause a high ecological risk. Bioavailable phosphorus (BAP) suggests the availability of an ample amount of bioavailable P fractions (average of 49.70% post-monsoon and 44.64% post-monsoon) in surface sediments. Sites 3, 13, 14, 20, 21, and 26 exhibited considerably higher BAP. Core 1 comprised significantly higher BAP (60.52%). Thus, sediments of GoK could act as a source of P to the overlying water if released from sediments.
UPDATED RESEARCH AND DEVELOPMENT ON SUNDARBAN MANGROVES - FOR NEW GENERATION RESEARCHERS.pdf
The rapid urbanization and economic development have resulted in an unprecedented pollution of the entire biosphere. Aquatic ecosystems have become a sink for the discharge of numerous pollutants ranging from nutrients, heavy metals, volatile organic compounds, hydrocarbons, pesticides, medicines, pathogens, and explosives. The accumulation of these pollutants poses a serious threat to aquatic biodiversity, and drinking contaminated water poses severe health hazards in humans. Phytoremediation, an eco-accommodating process, aids in the maintenance of aquatic ecosystem functionality by detoxifying, decomposing, converting, or chelating contaminants, allowing for the proper treatment of wastewater-contaminated water bodies. The development of phytoremediation technology was facilitated by the economic aspects and side effects of conventional treatment technologies. Nevertheless, constructed wetlands have acquired popularity among the numerous accessible methods for treating and recycling diverse wastewaters because they fulfill the criteria of sustainability, public health maintenance, esthetic balance, design intricacy, and cost. The prolonged-release of untreated industrial waste, domestic sewage, accidental spills, rainfall run-off, and direct solid waste disposal all have a substantial influence on aquatic environments. Both live and dead macrophyte biomass may be utilized in phytoremediation; however, dead biomass is typically favored for treating industrial effluents due to lower cost, ease of disposal, and lack of active biochemical machinery that causes metal toxicity and plant death. Some of the barriers to translating phytoremediation technology from the lab to the field include the issue of disposing of biomass and the seasonal growth of aquatic macrophytes. Yet, via numerous works, an eco-sustainable model has been created that could mitigate some of the restrictions. Macrophyte waste biomass has a wide range of productive uses. Future potential for the utilization of macrophytes in phytoremediation investigations includes genetic engineering, biodiversity exploration, and X-ray diffraction spectroscopy. This emerging technology may advance environmental science and technology using a multidisciplinary and integrated approach. This review, thus focuses on the various contaminants found in aquatic ecosystems, their treatment by various phytoremediation processes, some successful phytoremediation studies conducted so far for remediation purposes, and myriad types of constructed wetlands utilized for attenuating pollution levels in various types of wastewaters to bring them down to permissible levels.
In this research, the modified Canadian water quality index (MCWQI) was successfully applied with other common sediment indices for quality assessment of sediments from two Egyptian Mediterranean harbours: Port Said (PS), and Damietta Harbour (DH). The geochemical analysis demonstrated the dominance of the sandy-mud texture for PS sediments, while it was muddy for DH sites. Organic carbon, and total phosphorus in DH (0.46%; 1.08%) were slightly higher than in PS (0.32; 1.07%), while total carbonate was higher in PS (12.12%) compared to DH (10.63%). Eight heavy metals (HMs) showed a similar order of abundance with higher records in DH for HMs (except Pb). Ecotoxicologically, HMs levels were lower than the effects range low (ERL), suggesting no adverse effects; however, Ni and Cr might cause impacts up to 40 - 90% (˃ effects range median; ERM), particularly in DH. Environmental indices (e.g., MCWQI) revealed that sediments of DH were more contaminated than PS, with a marginal (∼ 59%) and a fair (∼ 70%) quality, respectively. Statistically, good correlations with a noticeable trend of loadings among studied parameters were recognized in PS, compared to DH. The study emphasized the vital roles of the topography, current movement, and levels of activities control the distribution of contaminants, pollution status and hence sediment quality.
PREFACE
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Dr. Tanmay Ray Chaudhuri
Dr. Kakoli Banerjee
PREFACE
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Dr. Tanmay Ray Chaudhuri
Dr. Kakoli Banerjee
PREFACE
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Dr. Tanmay Ray Chaudhuri
Dr. Kakoli Banerjee
The term ‘mangrove’ has originated from the Portuguese word ‘Mangue’, which means the community and the English word ‘Grove’, which means trees or bushes. According to Mepham and Mepham (1984), the term has been inconsistent and confusing in the past. Mangroves are basically evergreen sclerophyllous, broad-leaved trees with aerial root like pneumatophores or stilt root and viviparously germinated seedlings (UNESCO, 1973).
Mangroves are circumtropical in distribution and this forest community occupies approximately 75% of the total tropical coastline. Northern extension of this coastline occurs in Japan (31022/ N) and Bermuda (32020/ N), whereas, southern extensions are in New Zealand (38003/ S), Australia (38045/ S) and on the east coast of South Africa (32059/ S). Globally, mangroves are distributed in 112 countries and territories. It is interesting to note that mangrove plants are not native to the Hawaiian Islands - 6 species have been introduced there since the year 1900. The mangrove diversity is more in Southeast Asian countries . The region holds nearly 75% of the world’s mangrove species with the highest species diversity found in Indonesia with 45 species, followed by Malaysia (36 species) and Thailand (35 species). India is no less in terms of the number of mangrove species (34 species of true mangroves) and hence is considered as one of the mega biodiversity countries in the world.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Dr. Tanmay Ray Chaudhuri
Dr. Kakoli Banerjee
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Dr. Tanmay Ray Chaudhuri
Dr. Kakoli Banerjee
If anybody ever happens to visit a coastal area, mudflats along the estuary or river mouths, unique vegetation at the land – sea interface is observed with some peculiar features like presence of pneumatophores, stilt roots, viviparous germination etc. These are called mangroves. Mangroves are one of the best natural reservoirs of the planet Earth, where many flora and fauna are yet untapped in terms of their benefits to mankind.
Mangrove forest offers several ecosystem services, which are essential to run the wheel of civilization as well as to support the livelihood of people living and dependent on the coastal resources. The conservation of mangroves is fundamental to all marine biological processes, for maintenance of biodiversity and ecosystems and for primary and secondary productions that support human needs.
Competition for limited resources has intensified with human population growth in coastal regions and the exploitation of mangroves for economic activities and livelihoods has become almost a universal picture. Today the rapid pace of urbanization, intense industrial activities, unplanned expansion of aquaculture and tourism has deteriorated the mangrove ecosystem to a great extent. Even today we are least bothered of the loss we will face in future not only in terms of various economically important products, but also in terms of ecosystem stability, biogeochemical cycle, protection against sea level rise, erosion, natural disaster etc. We believe that such threatened ecosystems can no longer provide their optimum biological functions and regulate services that sustain coastal economic production and livelihoods. The concept of conservation through lanes of alternative livelihoods is very crucial in this context.
The present book has critically presented the data bank for each type of mangrove resources not merely in the form of text description, but also through case studies and research papers that are the outcomes of research projects and pilot programmes carried out in different parts of the world. For a long time there was a need felt for this type of book on mangroves and more specifically Sundarban mangroves for common people. This would reduce the communication gap at different levels. Hence while writing this book we intentionally tried to bye pass the hard core mathematical models related to mangroves and their interaction with natural forces. We hope that the present book would not only provide more light of analysis on the existing knowledge of this remarkable ecosystem, but will also encourage the common mass, students, researchers and policy makers to feel deeply the problems and needs of mangrove conservation.
Dr. Abhijit Mitra
Coastal waters globally are increasingly impacted due to the anthropogenic loading of nitrogen (N) from the watershed. In order to assess dominant sources of N contributing to the eutrophication of the Little Narragansett Bay estuary in New England, we carried out an annual study of N loading from the Pawcatuck River. We conducted weekly monitoring of nutrients and nitrate (NO3−) isotope ratios (15N / 14N, 18O / 16O and 17O / 16O) at the mouth of the river and from the larger of two Waste Water Treatment Facilities (WWTFs) along the estuary, as well as seasonal along-river surveys. Our observations reveal a direct relationship between N loading and the magnitude of river discharge, and a consequent seasonality to N loading into the estuary – rendering loading from the WWTFs and from an industrial site upriver more important at lower river flows during warmer months, comprising ~23 % and ~18 % of N loading, respectively. Riverine nutrients derived predominantly from deeper groundwater and the industrial point source upriver during low base flow in summer, and from shallower groundwater and surface flow at higher river flows during colder months. Loading of dissolved organic nitrogen appeared to increase with river discharge, ostensibly delivered by surface water. The NO3− associated with deeper groundwater had higher 15N / 14N ratios than shallower groundwater, consistent with the expectation fractionation due to partial denitrification. Along-river, NO3− 15N / 14N ratios showed a correspondence to regional land use, increasing from agricultural and forested catchments to the more urbanized watershed downriver, with the agricultural and urbanized portions of the watershed contributing disproportionately to total N loading. Corresponding NO3− 18O / 16O ratios were lower during the warm season, a dynamic that we ascribe to increased biological cycling in-river. The 18O / 16O isotope ratios along-river were consistent with the notion of nutrient spiraling, reflecting NO3− input from the watershed and in-river nitrification and its coincident removal by biological consumption. Uncycled atmospheric NO3−, detected from its unique mass-independent NO3− 17O / 16O vs. 18O / 16O fractionation, accounted for
Life on Earth would have been impossible without the cycling of inorganic elements through several physico-chemical and biological compartments. The chapter deals with the cycling of major elements in general, but the alteration of biogeochemical cycles through human intervention is a key issue of this chapter. The ground zero observation on the change of land-use pattern in the lower Gangetic delta has been addressed that has significant impact on the near-surface air temperature leading to alteration of biotic community and physico-chemical properties of the aquatic phase.
Defining the relationship between nutrients and parasitism is complicated by shifts in host physiology and population density, which can both mediate the effects of host diet on parasites and vice versa.
We examined the relationship between nutrient availability and an abundant parasite capable of both horizontal and vertical transmission (Hamiltosporidium tvaerminnensis) of a planktonic crustacean, Daphnia magna, in rock pools on Baltic Sea Skerry islands.
We found that the relative availability of nutrients directly affected infection prevalence; parasite prevalence was higher in pools with higher particulate N:P ratios. Infection prevalence was not related to Daphnia population densities. A complementary experiment that examined host responses to an N:P gradient in mesocosms indicated that high N:P ratios can increase spore load in the hosts.
We surmise that high N:P food increases Daphnia feeding rate, which increases their contact with parasite spores and leads to higher prevalence and more intense infections. We found no direct evidence that parasite‐induced changes in host nutrient use affected nutrient dynamics in pools. However, the relationship between diet N:P and the parasite's prevalence and load is consistent with previously documented patterns of this parasite's effect on host nutrient use.
Taken together, this study suggests that high N:P ratios in food may benefit the parasite in multiple ways and could create environments that favour horizontal transmission over vertical transmission for parasites capable of both transmission routes. If so, nutrient limitation could have long‐term consequences for host–parasite evolution.
Aquatic phase of the marine and estuarine ecosystems is an ideal solvent, and because of this reason seawater is a well-mixed solution of several salts and gases. The churning of seawater due to wave, currents and tidal actions accelerates the process of solubility of substances in the solvent. It is mainly because of thorough mixing the ionic composition of the major ions of the seawater (except bicarbonate and fluoride) exhibits uniform spatial variation, i.e. the composition is almost the same from place to place as well as from depth to depth. Thus, the ratio of one major ion to the other remains almost constant.
Sedimentation is the end stage of surface geochemistry. At this point the geological materials that have been affected by surface chemical influences are deposited and become essentially closed systems isolated from the surface chemical effects of air and rainwater where the sediments will be subjected to changes in pressure and temperature. The basic context of surface geochemistry is that of element migration and change under different chemical conditions whereas the regime of sediment burial is one of more or less constant chemical conditions where new minerals can be formed due to changes in the physical conditions pressure and above all temperature. The early stages of burial (diagenesis) allow some migration of geo-materials, water, but usually on a relatively limited scale. The initial stages of sedimentation can be affected by biological activity, which influences pH and Eh. Major actors in the control of elemental oxidation state and the form (dissolved ionic, particulate) that elements have in the surface transportation and especially sedimentation process are biological and especially microbial agents. The oxidation state of Fe, Mn and S are an especially important source of energy for many forms of bacteria and vice versa. The chemical state of these elements depend upon the activity of these elements in the sedimentation environment.
Cechą charakterystyczną XX i początku XXI wieku, był i jest z jednej strony gwałtowny rozwój we wszystkich dziedzinach życia, z drugiej zaś rosnące zagrożenie dla środowiska naturalnego człowieka (Howarth, 2008; Howarth i in., 1995, 1996; Nixon i in., 1996). W pracach naukowych pojawiło się pojęcie antropopresji, pod którym rozumie się ogół działań człowieka (zarówno planowanych jak i przypadkowych) mających wpływ na środowisko przyrodnicze (Meybeck i in., 1989; Meybeck, 2001). Skala występowania antropopresji w środowisku naturalnym człowieka na przestrzeni minionych dekad narzuca konieczność holistycznego spojrzenia we wszelkich badaniach środowiskowych (Nixon, 2009). Z definicji, holistyczne podejście w zarządzaniu ekosystemem, oznacza takie podejście do środowiska, które w pełni uznaje szeroki wachlarz interakcji w ramach ekosystemu, włączając działalność człowieka, a tym samym wyłącza ze sfery zainteresowań badanie jedynie oderwanych pojedynczych zagadnień, gatunków, czy funkcji ekosystemu bez łączenia ich w całość. Spojrzenie holistyczne wymaga od badacza pełnego zrozumienia faktu, iż wszelkie zjawiska tworzą układy całościowe, podlegające swoistym prawidłowościom, których nie można w pełni zrozumieć na podstawie wiedzy o prawidłowościach rządzących tylko wybranymi ich składnikami. Całości nie da się, bowiem sprowadzić do sumy jej składników. Funkcjonowanie ekosystemu, to cały szereg procesów fizycznych, chemicznych i biologicznych, które wykazują interakcję nieliniową. Nowoczesne badania wymagają holistycznego podejścia w określeniu nie tylko przyczyn perturbacji w funkcjonowaniu dowolnego ekosystemu, ale także w określeniu obecnych i prognozowania przyszłych konsekwencji tych perturbacji. (...)
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