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Nutrient enrichment of estuarine submersed vascular plant communities. 1. Algal growth and effects on production of plants and associated communities
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... The most common anthropogenic threats to Z. marina have been eutrophication and sedimentation from urban and agricultural runoff (Short and Wyllie-Echeverria, 1996;Short et al., 2006;Waycott et al., 2009), which decrease the amount of light available to plants for photosynthesis, threatening their viability. Moreover, in systems with high nutrient loading, epiphytes and fast-growing macroalgae outcompete eelgrass since they uptake nutrients more effectively and have relatively lower light requirements to sustain growth (Harlin and Thorne-Miller, 1981;Short and Kaldy, 1995;Twilley et al., 1985). The resulting changes to Z. marina habitats include changes in shoot density and canopy height, declines in cover and biomass within meadows, and reductions of overall meadow extent (Waycott et al., 2005;Short et al., 2006;Collier et al., 2012;Schmidt et al., 2012). ...
... where Be is epiphyte coverage of the leaf and Ke is the biomass-specific epiphytic light attenuation coefficient (Twilley et al. 1985;Vermaat and de Bruyne 1993;Kemp, Bartleson, and Murray 2000). The required percentage of surface light that reaches the leaf blade for survival and growth varies not only between species but also for the same species in different regions (Lee, Park, and Kim 2007) (Table 6). ...
Submerged aquatic vegetation (SAV) growing in estuarine and coastal marine systems provides crucial ecosystem functions ranging from sediment stabilization to habitat and food for specific species. SAV systems, however, are sensitive to a number of environmental factors, both anthropogenic and natural. The most common limiting factors are light limitation, water quality, and salinity, as reported widely across the literature. These factors are controlled by a number of complex processes, however, varying greatly between systems and SAV populations. This report seeks to conduct an exhaustive examination of factors influencing estuarine and coastal marine SAV habitats and find the common threads that tie these ecosystems together. Studies relating SAV habitats in the United States to a variety of factors are reviewed here, including geomorphological and bathymetric characteristics, sediment dynamics, sedimentological characteristics, and water quality, as well as hydrologic regime and weather. Tools and methods used to assess each of these important factors are also reviewed. A better understanding of fundamental environmental factors that control SAV growth will provide crucial information for coastal restoration and engineering project planning in areas populated by SAVs.
... Periphyton has a beneficial effect on pollutant removal through the release of oxygen necessary for the oxidation of pollutants as well as the uptake of nutrients. On the other hand, the excessive growth of periphyton can seriously limit the photosynthesis of submerged macrophytes by blocking the PHAR [22]. ...
Constructed wetlands (CWs) for wastewater treatment are engineered systems that are designed and operated in order to use all natural processes involved in the removal of pollutants from wastewaters. CWs are designed to take advantage of many of the same processes that occur in natural wetlands, but do so within a more controlled environment. The basic classification is based on the presence/absence of wastewater on the wetland surface. The subsurface flow of CWs can be classified according to the direction of the flow to horizontal and vertical. The combination of various types of CWs is called hybrid CW. The CWs technology began in the 1950s in Germany, but the major extension across the world occurred during the 1990s and early 2000s. The early CWs in Germany were designed as hybrid CWs; however, during the 1970s and 1980s, horizontal subsurface flow CWs were mostly designed. The stricter limits for nitrogen, and especially ammonia, applied in Europe during the 1990s, brought more attention to vertical subsurface flow and hybrid systems. Constructed wetlands have been used to treat various types of wastewater, including sewage, industrial and agricultural wastewaters, various drainage and runoff waters and landfill leachate. Recently, more attention has also been paid to constructed treatment wetlands as part of a circular economy in the urban environments: it is clear that CWs are a good fit for the new concept of sponge cities.
... A large body of studies on periphyton (epiphyte) load covering the leaves of submerged plants in marine and freshwater environments shows its potential to affect plant's productivity, synthesis and accumulation of reserve substances, as well as its survival. Twilley et al., 1985 summarize that it is due to the attenuation of available PAR (photosynthetic active radiation) (e.g. Sand-Jensen, 1977, Phillips et al., 1978Balthuis and Woelkerling, 1983 and reduction of the inorganic carbon diffusive transport (Send-Jensen, 1977). ...
Quantifying PAR attenuation caused by periphyton is a crucial step in setting good management criteria for seagrass habitats protection. To help
forward the process of its implementation in the Bulgarian coastal waters we set out to verify experimentally this relationship within several perennial,
shallow, sublittoral seagrass meadows. Four types of functional relationships between the dry weight and the PAR quantity have been tested: exponential
rise to a maximum, Michaelis-Menten, natural logarithm, negative exponential function (both constrained and unconstrained form). The exponential
rise to a maximum proved to be the most appropriate curve for a description of the data under the current experiment. The coefficients obtained: 73.22
(71.02 ÷ 75.48, 95% confidence interval) and 0.8299 (0.7507 ÷ 0.9300, 95% confidence interval) are in the range reported on other experimental studies.
The application of a variable for evaluation of the effect of the species composition, especially within the higher loads interval, would improve the curve
precision. Nevertheless, it can be useful to assess the seagrasses habitat suitability and the risk of light stress in the Burgas Bay (the Black Sea).
... Although short-term local effects may stress plants, dilution and rapid degradation of herbicides to less toxic metabolites (T.W. Jones & Winchell, 1984) are thought to prevent widespread impacts. Ultimately, eutrophication was identified as the primary cause (Kemp et al., 1983;Twilley et al., 1985) by stimulating phytoplankton growth that reduces light penetration through the water column and enhances epiphytic growth on seagrass leaves . These changes reduce the depth range over which it can survive (Goldsborough & Kemp, 1988;K. ...
Critical habitats that have been impacted by anthropogenic pressures in Chesapeake Bay (CB) and the northern Adriatic Sea (NAS) include seagrass beds and tidal marshes (both systems), oyster reefs (CB), coral reefs (NAS), beaches (CB), and coastal lagoons (NAS), all of which support important ecological services. Major anthropogenic pressures include excess nutrient loading (eutrophication), coastal development, climate change (sea‐level rise and increases in water temperature), invasive species, and overfishing. Acidification (driven by both climate change and eutrophication) likely impacts calcareous organisms more in CB than in the NAS. While the rapid loss of oyster bars during the 20th century was primarily due to overfishing and disease, loss of oxygenated habitat also contributed. These pressures are likely to persist, and may become greater in the future, yet there are signs of recovery. The CB seagrass beds began a comeback in the mid‐1980s after decades of decline from eutrophication, mainly driven by anthropogenic nitrogen reductions. In the NAS, eutrophication in lagoons led to episodic bottom‐water anoxia and a shift from benthic to pelagic primary production. Eutrophication and overgrazing by sea urchins contributed to the decline of the NAS brown algal forests. Following nutrient reductions over the past two decades, there has been a slight recovery of canopy‐forming algae along the Croatian Istrian peninsula and the Slovenian coastline.
... These findings are parallel to previous reports about P. perfoliatus (Burns et al. 1995). According to Twilley et al. (1985), P. perfoliatus grows in oligohaline to mesohaline waters. We recorded P. perfoliatus mainly from lentic habitats, out of 54 wetlands only seven were fast flowing rivers and canals. ...
Clasping-leaved Potamogeton L. species growing in Turkey are P. praelongus Wulfen and P. perfoliatus L. There exists no detailed study about distribution, habitat requirements, and anatomical properties of the Turkish populations of the two species. Potamogeton perfoliatus is widespread throughout the country but P. praelongus was recorded only from a single locality. Therefore, P. praelongus is rare and endangered in Turkey. In this study, we recorded presence of P. perfoliatus in 54 wetlands based on examination of 86 herbarium specimens. Physical and chemical parameters of the water bodies where the two species occur were measured from 24 sites for P. perfoliatus and from one site for P. praelongus. According to our findings, P. praelongus grows in an alpine lake with oligotrophic, calcareous and alkaline water. Potamogeton perfoliatus occupies diverse habitats but prefers deep lentic water bodies with high pH and low salinity levels. Stem anatomy of the species were studied based on three individuals for P. praelongus and 35 individuals for P. perfoliatus. Morphological features of the species were also investigated and descriptions based on Turkish material were prepared. We provided the distinguishing anatomical and morphological characters between the species. Our anatomical findings showed that P. praelongus specimens have eight vascular bundles in contrast to previous reports on the species. Our results can be used for future monitoring of the two submerged Potamogeton species as we provide detailed information about their current distribution pattern and habitat features.
... Similar results can be found in earlier work on a J. Guan, et al. Ecological Indicators 119 (2020) 106775 variety of freshwater macrophytes (Sand-Jensen, 1977;Phillips et al., 1978;Bulthuis and Woelkerling, 1983;Twilley et al., 1985;Asaeda et al., 2004). Besides periphytic loads, aging has been shown to lead to changes in photosynthesis (Mazzella and Alberte, 1986), synthesis of proteins (Thayer et al., 1984;Zieman et al., 1984), and other physiological processes (Cebrián and Duarte, 1994) that influence growth rates of macrophytes. ...
... Bila hal ini berlangsung cukup lama, radiasi cahaya yang diterima oleh permukaan makrofita akan terhambat karena terhalang oleh biomassa epifiton. Akibatnya, produktivitas primer perairan tersebut akan menurun drastis karena penurunan populasi makrofita, meskipun pertumbuhan fitoplankton dan epifiton meningkat (Twilley et al., 1985), Morfologi spesies makrofita tertentu, terutama batang dan bentuk daun, dapat memengaruhi komposisi dan kelimpahan epifiton (Messyasz et al., 2009;Chung & Lee, 2008). Menurut Santos et al. (2018), struktur taksonomi mikroalga sangat ditentukan oleh tipe substratnya. ...
... Both eutrophication and sedimentation decrease the amount of light available to eelgrass for photosynthesis. Moreover, in systems with high nutrient loadings, epiphytes and fast-growing macroalgae outcompete eelgrass since they uptake nutrients more effectively and have relatively lower light requirements to sustain growth (Harlin and Thorne-Miller 1981;Short and Kaldy 1995;Twilley et al. 1985). Other anthropogenic activities having direct impacts on the distribution of eelgrass by reducing water clarity and/or uprooting plants include dredge and fill, land reclamation, and dock and jetty construction. ...
Increasing the protection of coastal vegetated ecosystems has been suggested as one strategy to compensate for increasing carbon dioxide (CO2) in the atmosphere as the capacity of these habitats to sequester and store carbon exceeds that of terrestrial habitats. Seagrasses are a group of foundation species that grow in shallow coastal and estuarine systems and have an exceptional ability to sequester and store large quantities of carbon in biomass and, particularly, in sediments. However, carbon stocks (Corg stocks) and carbon accumulation rates (Corg accumulation) in seagrass meadows are highly variable both spatially and temporally, making it difficult to extrapolate this strategy to areas where information is lacking. In this study, Corg stocks and Corg accumulation were determined at 11 eelgrass meadows across New England, representing a range of eutrophication and exposure conditions. In addition, the environmental factors and structural characteristics of meadows related to variation in Corg stocks were identified. The objectives were accomplished by assessing stable isotopes of δ13C and δ15N as well as %C and %N in plant tissues and sediments, measuring grain size and 210Pb of sediment cores, and through assessing site exposure. Variability in Corg stocks in seagrass meadows is well predicted using commonly measured environmental variables such as grain size distribution. This study allows incorporation of data and insights for the northwest Atlantic, where few studies on carbon sequestration by seagrasses have been conducted.
This paper provides a summary of research conducted to investigate possible causes of the decline in abundance of submerged aquatic vegetation beginning in the late 1960s. Three factors are emphasized: runoff of agricultural herbicides; erosional inputs of fine-grain sediments; nutrient enrichment and associated algal growth. The results are synthesized into an ecosystem simulation model which demonstrated relative potential contributions, where nutrients greater than sediments greater than herbicides. Other factors and mechanisms are also discussed along with resource managements options.
A 2-year field study was conducted to determine the effects of fertilization on elodea (Elodea canadensis Michx.), eurasian watermilfoil (Myriophyllum spicatum L.), and heartleaf pondweed (Potamogeton pulcher Tuckerm.). Plants, water, and sediment were sampled and inorganic mineral contents determined. Water concentrations of NO 3 , NH 4 , P, and K increased sharply following fertilization and generally reached maximum values within 7 days after treatment. Concentrations of these nutrients decreased rapidly after reaching maximum values. In the first year, plant growth was not increased due to fertilization while in the second year only heartleaf pondweed produced significantly greater yields. Elodea and eurasian watermilfoil grew better in the control environment, presumably due to less competition from algae, whose growth was increased by the addition of fertilizer. At the end of the study the top 1.3 cm of bottom sediment had increased in cation exchange capacity (C. E. C.), organic matter, total N, and available P for all treatments while the underlying sediment remained relatively unchanged. Available P was greater in the surface of the fertilized sediment than in the surface of the control sediment.
Greenhouse experiments to determine optimal levels of inorganic nitrogen and phosphorous for growth of aquatic plants were conducted as a basis for establishing eutrophic conditions in twenty experimental ponds. Various formulations, levels, and ratios of inorganic N and P were applied to cultures of aquatic vascular plants (Myriophyllum spicatum var. exalbescens, Potamogeton crispus and Elodea canadensis) and freshwater phytoplankton populations (mostly Chlorophyceae) established in battery jars containing natural soil and water. Nutrient levels applied ranged from 0.015–50 mg/l N and 0.005-5.0 mg/l P. The yields of the plants after five weeks growth under experimental conditions were used as indices of response.
The highest nutrient levels produced the best growth of phytoplankton while the lower levels resulted in higher yields of vascular plants. Filamentous algae grew best at the intermediate nutrient levels. High yields of vascular plants never coincided with large phytoplankton populations. At the highest nutrient levels applied, no vascular plant growth occurred. Of two inorganic phosphorous compounds evaluated, CaH4 (PO4)2 produced the greater yields. Smaller differences were apparent amoung three inorganic nitrogen compounds.
This laboratory data suggest that future uncontrolled enrichment of natural bodies of water will result in the growth of larger populations of phytoplankton at the expense of benthic aquatic macrophytes. These conclusions are being examined under natural conditions in experimental ponds.
: Physical, chemical and biological influences of submersed vascular plants (dominated by Potamogeton perfoliatus and Ruppia maritima) on their surrounding environment are summarized for portions of upper Chesapeake Bay. Rates of accretion of organic matter in these ecosystems were high owing to the combined effects of vascular plant and associated algal production and the trapping of particulate organics of phytoplanktonic origin. Time-series observations of seston along transects traversing vegetated bottoms indicated significantly less turbid water over the plant beds, due both to increased deposition and to decreased resuspension of fine-grain sediments. Submersed plants provided a preferred habitat for many animal populations, and abundance of fishes (predominantly juveniles) was significantly greater in these plant beds than in adjacent unveqetated areas. Recent declines in several species of migrating waterfowl which feed directly on plant material were highly correlated with contemporaneous decreases in plant distribution. Rapid uptake of dissolved inorganic nitrogen (N) and phosphorus (P) was demonstrated for these communities, with subsequent incorporation into plant material via both growth and facultative increases in percent N and P composition. Upon senescence and death, submersed vascular plants decayed at moderate rates, with relatively slow releases of nutrients and low dissolved oxygen (O2) demand compared to algae (micro and macro) and to marsh grass. Thus, organic carbon (C) from these submersed plants is transferred to microbial food-chains, with minimal secondary effects of O2 depletion and nutrient enrichment. Part of the influence of these plant communities on the upper Bay is summarized in terms of three materials budgets for 1960, where these plants contributed 33% to the organic C budget, while acting as a seasonal sink for 210 and 7% of the total sediment and nitrogen inputs (respectively) to tne estuary.