Figure 5 - uploaded by Adrian E. Williams
Content may be subject to copyright.
Isopleth diagrams showing changes in seasonal mean values of SRP, TP, dissolved inorganic nitrogen, chlorophyll a, total crustacean zooplankton biomass and total daphnid biomass between 1990 and 2002 in Little Mere. Each diagram is based on 52 mean values (four seasons × 13 years).
Source publication
1. Lake restoration from eutrophication often rests on a simple paradigm that restriction of phosphorus sources will result in recovery of former relatively clear-water states. This view has apparently arisen from early successful restorations of deep lakes in catchments of poorly weathered rocks. Lakes in the lowlands, however, particularly shallo...
Contexts in source publication
Context 1
... Mere showed substantial changes in water chemistry following diversion of sewage effluent (Fig. 5). TP concentration declined rapidly from peaks of around 5 mg P L )1 (annual mean 2.35 mg L )1 ) in 1990 to an annual mean of 167 lg P L )1 (within-year peak, 330 lg L )1 ) by 1994. Regressions showed signi- ficant decreases in TP concentration with time for the entire data set ...
Context 2
... by autumn run-off, of SRP released from the sediment in summer. Ammonium concentrations, with peaks over 7 mg N L )1 before diversion, fell rapidly after effluent diversion, in parallel with those of phosphorus, and the nitrogen budget became dominated by nitrate entering from Mere Mere. Winter concentrations of DIN (almost entirely nitrate) (Fig. 5) in the two meres are highly correlated (r ¼ 0.85, P < ...
Context 3
... mean chlorophyll a concentration showed no significant change (regression analysis) over the period 1990-2002 nor in any subset of years. However, spring concentrations fell when the pre-and post- diversion periods were compared (Fig. 5). Prior to diversion, spring concentrations were 65 ± 59 lg L )1 (mean ± SD). In 1992/93, immediately after diversion, they fell to very low values (5.9 ± 5.3), then rose a little in 1994-2002 (17.0 ± 7.4), whilst mean values for the summer rose and were 7.0 ± 2.5 (pre-1991), 6.8 ± 2.3 (1992/93) and 42 ± 24 (1994-2002), respect- ively. ...
Similar publications
Optimizing the utility of constructed waterways as residential development with water-frontage, along with a productive and functional habitat for wildlife is of considerable interest to managers. This study examines Lake Hugh Muntz, a large (17 ha) freshwater lake built in Gold Coast City, Australia. A ten year water quality monitoring programme s...
Societies' growing global footprint is causing a rapid increase in the demand for natural resources (i.e. ecosystem services), while also reducing the capacity of ecosystems to provide them. Freshwater ecosystems contribute disproportionately to ecosystem services but are also particularly vulnerable to global environmental change. The provisioning...
Due to the increasing industrialization and urbanization, the requirement of clean water has been growing quite fast and it has the potential to keep increasing. There are many regions facing water crisis even some countries with a rich water source. In this study, three types of water (tap, ground, and light sewage) have been collected from differ...
A simulated horizontal flow constructed wetland (CW) has been designed with gravel medium and aquatic plants Typha latifolia and Polygonum hydropiper to assess its performance efficiency for sewage treatment. Monitoring of fully developed CW revealed a high removal of nutrients and metals from sewage after treatment at varying retention times. The...
Water hyacinth (Eichhornia crassipes) is a fast growing invasive aquatic plant often covers water bodies. It has been a problem worldwide. Fast-growing and rapidly expanding omnivorous tilapia is likely the suitable species for aquaculture. Since the fish farmers are adversely affected by high cost feed, the use of water hyacinth as a protein sourc...
Citations
... It is still under debate on which nutrient(s) policy makers should focus to have the highest potential to control phytoplankton biomass and cyanobacterial blooms. There are many case studies pointing toward N (Moss et al. 2005;Scott and McCarthy 2010;Newell et al. 2019), P (Schindler 1975;Schindler et al. 2016;Chorus et al. 2020) or both (Shatwell and Köhler 2019;Lewis et al. 2020). By achieving low enough concentrations of N and P in the water, mitigation strategies to limit severe bloom formation may suffice focusing on either N or P (Chorus and Spijkerman 2021). ...
Nutrient loading of freshwater and marine habitats has increased during the last century as a result of anthro-pogenic activities. From the 1980s onwards, following implementation of new policy targeting eutrophication, total phosphorus (TP) and total nitrogen (TN) loads were reduced in many European waters. Often, however, decreases in TP were stronger as compared to TN, leading to increased TN : TP ratios. Our analysis shows that the large and shallow lake IJsselmeer (the Netherlands) experienced a similar trend, whereas TN was reduced by 50%, TP was reduced by 89% between 1975 and 2018. Most of this nutrient load reduction was achieved before the year 2000, changes in nutrient concentrations in the lake became smaller afterwards, especially for TN, leading to a further increase in stoichiometric imbalance up to a yearly averaged TN : TP (molar) of 296 in 2018. The observed changes in nutrients were accompanied by a decline in total phytoplankton biomass, and slight declines in phytoplankton genus evenness and diversity. Although biomass decreases likely resulted from the overall decrease in nutrient availabilities, the reduced diversity may have resulted from the shift toward very high TN : TP ratios that indicate relatively low TP levels and enhanced competition for phosphorus. Overall, our findings demonstrate long-term trends with decreased phytoplankton biomass and diversity following reduced nutrient concentrations and enhanced stoichiometric imbalance. Ultimately, such changes at the food web base may alter the structure and functioning of the entire aquatic food-web in lake IJsselmeer.
... Surface fresh waters are characterised by complex interactions between multiple abiotic and biotic factors that shape the communities inhabiting them through multiple functional, behavioural, genetic, plastic and adaptive processes (Colgan & Ponder, 1994;Dodds et al., 2019;Moss et al., 2005;Silknetter et al., 2020). Research on ground waters has increased in recent years, with growing recognition of their key role. ...
Springs are environments that can provide general insights into factors favouring diversity in ecotones, but they are often neglected in freshwater studies. One of the challenging processes acting in ecotones is the landscape of fear (LOF), the space–time variation of perceived predation risk. Spring exploitation often involves species that are mesopredators in surface fresh water and that can become apex predators in ground water, as in the case of the fire salamander larvae ( Salamandra salamandra ). Here, we aim to determine whether the activity and foraging patterns of the fire salamander in springs are affected by LOF.
We surveyed the night‐ and daytime abundance of fire salamander larvae in 15 springs to assess predator occurrence. We also reared 48 salamander larvae with and without non‐lethal exposure to predators within tanks simulating groundwater or surface freshwater light features. Before and after a month of rearing, we tested larva efficiency in catching prey when exposed to predator chemical cues, both in light and dark conditions.
In the field, the number of active fire salamander larvae was significantly higher during the night. At night, the number of active larvae across the transition area between ground water and surface water was higher in plots closer to the surface.
Testing and rearing conditions significantly affected larva behaviour, and prey capture was significantly more effective in light conditions. It was less successful in larvae reared with predator chemical cues and in the presence of predators. Moreover, larvae reared with predators under light conditions were slower than those raised with predators in dark conditions.
Our results show that LOF can interact with extant environmental features and constitute a significant behavioural pressure for mesopredator species living in freshwater ecotones.
... Typically, the phytoplankton community has responded as well. The contribution of non-heterocystous cyanobacteria decline substantially, while N 2 -fixing cyanobacteria, dinophytes, cryptophytes and chlorophytes increased (Jeppesen et al., 2002(Jeppesen et al., , 2005aMoss et al., 2005). An open question is how a delay in the P reduction in lakes but fast response of N will affect the phytoplankton community response. ...
... Despite the significant reduction of TN, the lake was still eutrophic with the mean value above the hypereutrophic of TN and TP concentration thresholds (TN > 1.4 mg/L, TP > 0.05 mg/L, USEPA, 2009). Moss et al. (2005) and Schindler et al. (2008) demonstrated that N 2 -fixing cyanobacteria appeared in significant abundance within weeks of reducing inputs of TN at constant inputs of TP. A recently analysis of data from Lake Taihu has also shown the biomass proportion of N 2 -fixing cyanobacteria increased, which corresponded to deceased TN: TP mass ratios after 2007 . ...
Response of aquatic organisms to eutrophication have been well reported, while less studies are available for the recovery of eutrophic lakes following a reduction in the external loading, especially for systems where nitrogen is reduced but the phosphorus concentration is maintained high due to internal loading. Diatoms are nitrate (NO3-N) opportunists but can also use ammonium (NH4-N). They may, therefore, be more sensitive to nitrogen reduction than other algae that typically prefer NH4-N. We document the variations of nutrients and diatoms in subtropical, eutrophic Lake Taihu over 28 yr during which a reduction of the external loading resulted from lake management. According to the results of change point analysis, data on environmental variables were divided into two periods (P1: 1992-2006; P2: 2007-2019) with two different seasons (WS: Winter-Spring; SA: Summer-Autumn), respectively. Compared with P1-WS, the concentration of NH4-N decreased significantly whereas NO3-N showed no significant change in P2-WS. In contrast, NH4-N concentrations were low and showed no significant changes in P1-SA and P2-SA and NO3-N decreased significantly in the latter period. Accordingly, NO3-N: NH4-N mass ratios in P1-SA and P2-WS were all significantly higher than those in P2-SA and P1-WS, respectively. The biomass of WS diatom increased significantly and the timing of the peak biomass shifted from P1-SA to P2-WS since 2007. The SEM analysis showed that NO3-N was retained as a statistically significant predictor for diatom biomass in P1-SA and significant effects of windspeed, zooplankton and NH4-N on diatom biomass in P2-WS. Windspeed and zooplankton have further changed the biomass of diatoms in the case of declining inorganic nitrogen. We conclude that the magnitude of vernal suppression or stimulation of diatom assemblages has increased, concomitant with the variations of NH4-N and NO3-N: NH4-N mass ratios. Diatoms response to NH4-N or NO3-N is apparently changing in response to water temperature in this eutrophic shallow lake. Thus, parallel reductions in external nitrogen loading, along with variations in dominant inorganic nitrogen, will stimulate the growth of diatom and therefore increase the total biomass of phytoplankton in still high internal phosphorus loading, which is should be regarded as a good sign of restoration measures.
... Accordingly, our study suggests that in eutrophic shallow lakes, N loading may increase the phytoplankton biomass in summer via both resource and grazer effects. Our study thus showed that decreasing N loading may lead to reduced eutrophication in summer in shallow lakes, which is consistent with long-term field investigations conducted in temperate shallow waterbodies, e.g., Lake Müggelsee in Germany and shallow meres in England (Moss et al., 2005;Shatwell and Köhler, 2019). ...
The effectiveness of controlling nitrogen (N) to manage eutrophication of aquatic ecosystems remains debated. To understand the mechanisms behind phytoplankton growth in shallow lakes (resource and grazing effects) under contrasting N loading scenarios, we conducted a 70-days mesocosm experiment in summer. The mesocosms contain natural plankton communities deriving from a 10-cm layer of lake sediment and 450 L of lake water. We also added two juvenile crucian carp (Carassius carassius) in each mesocosm to simulate presence of the prevailing omni-benthivorous fish in subtropical lakes. Our results showed that N addition increased not only water N levels but also total phosphorus (TP) concentrations, which together elevated the phytoplankton biomass and caused strong dominance of cyanobacteria. Addition of N significantly lowered the herbivorous zooplankton to phytoplankton biomass ratio and promoted the phytoplankton yield per nutrient (Chl-a: TP or Chl-a: TN ratio), indicating that summer N addition likely also favored phytoplankton growth through reduced grazing by zooplankton. Accordingly, our study indicates that summer N loading may boost eutrophication via both changes in resource and grazing control in shallow lakes. Thus, alleviation of eutrophication in shallow eutrophic lakes requires a strategic approach to control both nutrients (N and P) appropriately.
... Collectively, they form an array of wetland locations that are important regions of interest (Geneva 2008). Reference (Moss, Barker et al. 2005) accounted that the Meres discovered in the North West Midlands of England exists a total number of lakes of high preserval importance, despite being impacted by high nutrient masses produced from the agricultural activities and population habitations. Despite the correlation of meres with eutrophic criteria for many decades, the great absorbtion and significant change to marine plants have occured over the past 50-100 years. ...
Momentary changes in some criteria regarding the quality of water were examined by conducting field test and laboratory examination in Cole Mere during the summer months (June, July and August) of 2013. 10 locations were chosen (inside the lake) and each was sampled nearly one month away from the other. The average surface water temperature was documented in June, July and August samplings were 14.1 °C, 21.9 °C and 18.2 °C respectively. The variations in the average temperature were numerically notable (p=<0.001). The average absorption levels of Cholorophyll a were 9.3 μgl⁻ ¹, 15.2 μgl⁻ ¹ and 39.8 μgl⁻ ¹for June, July and August respectively and there was a noticeable difference observed between the months at p=0.001. The detected momentary change and the rising levels of summer chlorophyll a absorption are exact evidence of eutrophic estate. However, no notable variations were observed regarding pH and declined oxygen between the months.
... It is still difficult to generalize their ecological requirements, as they can be ubiquistic, specifically preferring eutrophic conditions [29]. Anthropogenic eutrophication is recognized as a global environmental problem in terms of both freshwater biodiversity loss and harmful algal blooms due to the presence of toxins [30,31]. However, the impact of eutrophication may differ in large rivers and lakes, when compared to smaller water bodies, such as streams, ponds, bogs, and small lakes, as well as groundwater [32]. ...
Nitrogen is one of the essential elements limiting growth in aquatic environments. Being primarily of anthropogenic origin, it exerts negative impacts on freshwater ecosystems. The present study was carried out at the nitrate-vulnerable zone within the alluvial aquifer of the large lowland Drava River. The main aim was to investigate the ecosystem’s functionality by characterizing the bacterial and phytoplankton diversity of a small inactive gravel pit by using interdisciplinary approaches. The phytoplankton community was investigated via traditional microscopy analyses and environmental DNA (eDNA) metabarcoding, while the bacterial community was investigated by a molecular approach (eDNA). Variations in the algal and bacterial community structure indicated a strong correlation with nitrogen compounds. Summer samples were characterized by a high abundance of bloom-forming Cyanobacteria. Following the cyanobacterial breakdown in the colder winter period, Bacillariophyceae and Actinobacteriota became dominant groups. Changes in microbial composition indicated a strong correlation between N forms and algal and bacterial communities. According to the nitrogen dynamics in the alluvial aquifer, we emphasize the importance of small water bodies as potential buffer zones to anthropogenic nitrogen pressures and sentinels of the disturbances displayed as algal blooms within larger freshwater systems.
... Low concentrations of bioavailable N can limit phytoplankton over the long term, even with high concentrations of available P (Shatwell and Köhler 2019). The role of N can become more important in controlling primary production after nutrient reduction in some shallow lakes (Moss et al. 2005). Ratios of chl-a:TP have been used to provide information on potential P limitation (Spears et al. 2013) and in Lough Neagh the generally declining values of log ((chl-a:TP) +1) since 1993 to the end of the data series indicate that factors other than P are limiting primary production by phytoplankton. ...
... Low concentrations of bioavailable N can limit phytoplankton over the long term, even with high concentrations of available P (Shatwell and Köhler 2019). The role of N can become more important in controlling primary production after nutrient reduction in some shallow lakes (Moss et al. 2005). Ratios of chl-a:TP have been used to provide information on potential P limitation (Spears et al. 2013) and in Lough Neagh the generally declining values of log ((chl-a:TP) +1) since 1993 to the end of the data series indicate that factors other than P are limiting primary production by phytoplankton. ...
The long-term response of chlorophyll-a (chl-a) to changing lake water nutrient concentrations and increasing water temperature was investigated in Lough Neagh, a large, hypereutrophic lake in Northern Ireland. Trends in external and internal nutrient loading and their relation to lake nutrient concentrations were also established. Lake water concentrations of total P (TP) have increased since the 1990s but were not correlated with catchment inputs, which showed no trend. The characteristics of internal loading of P have changed since the mid-1990s, with an earlier and larger mass of P released from the sediments each summer. Catchment inputs of total oxidised N (NOx) decreased from the peak value of 10,186T/yr in 1995 to 5,396T/yr in 2011, coinciding with a reduction in lake water concentrations. External inputs and lake concentrations of NOx were highly correlated (R=0.88). Water temperature increased approximately 1C and was a predictor of variation in chl-a from 1974 to 2012. After the peak chl-a concentration in 1993, dissolved inorganic N (DIN) also became an important predictor, accounting for almost half of the 44% variance explained by a hierarchical partition model. Decreasing log (DIN:TP) ratios suggest that N limitation of chl-a has become more important in the lake recently.
... Lake restoration planning requires understanding the limnological characteristics of a lake to develop an appropriate and individualized approach that accounts for factors such as lake type, nutrient sources, and food-web structure (Hamilton, Collier, et al., 2016). This particularly applies to shallow lakes, which are generally more structurally complex than deep lakes (Moss et al., 2005) and can exhibit more variable responses to nutrient load reductions (Havens et al., 2001). Therefore, the requirement to collect information to adequately understand lake characteristics can hinder the development of sound restoration plans. ...
Shallow lake ecosystems are widely impaired by eutrophication. Lake restoration projects frequently fail or are only partially successful, reflecting that environmental managers face difficult challenges in addressing this complex problem. Key uncertainties relate to selecting appropriate methods and predicting the resulting response trajectory, that is, “what should be done, how much improvement should be expected, and how long will it take?” This review critically evaluates approaches applied to address eutrophication in shallow lakes. A set of shallow lake restoration case studies from across the globe, involving moderate to high effort monitoring, was evaluated to determine common features and to identify advantages/disadvantages and drivers of successful restoration projects. Approaches are broadly grouped into four categories: 1) external nutrient load reductions, 2) internal nutrient load reductions, 3) biomanipulation, and 4) hydrological manipulations. Case studies highlight that external load reduction is an essential component of successful restoration, although supplementary measures can support restoration goals. To inform planning and help set realistic expectations, the following key challenges to the restoration of shallow lakes were identified: 1) insufficient reductions in external nutrient loads, 2) biogeochemical lags, 3) resistance of a stable, algal-dominated state due to hysteresis in the turbidity–nutrient load relationship, 4) delayed macrophyte reestablishment, 5) climate change, 6) need for lake-specific approaches, and 7) social and political shortcomings. Managing these challenges is crucial to the success of shallow lake restoration projects.
... Although internal loading under seasonal anoxia maintains high phosphorus concentrations in the lake (Carvalho et al. 1995;Moss et al. 2005;Radbourne 2018), it is unlikely that mobilisation of DOC from lake sediments, observed from monitoring (Scott 2014) explains the unusual DOC results. If the bomb C was derived from remobilised lake sediment OC, we would also expect the signal to be evident in the uppermost sediment sample (* 2014), lake POC, or DIC from bacterial metabolism of DOC (Kritzberg et al. 2006), as is evident in Lower Lough Erne DIC D 14 C values (Keaveney et al. 2015). ...
We explored the roles of phytoplankton production, carbon source, and human activity on carbon accumulation in a eutrophic lake (Rostherne Mere, UK) to understand how changes in nutrient loading, algal community structure and catchment management can influence carbon sequestration in lake sediments. Water samples (dissolved inorganic, organic and particulate carbon) were analysed to investigate contemporary carbon sources. Multiple variables in a 55-cm sediment core, which represents the last ~ 90 years of accumulation, were studied to determine historical production rates of algal communities and carbon sources. Fluctuations in net primary production, inferred from sedimentary diatom abundance and high-performance liquid chromatography (HPLC) pigment methods, were linked to nutrient input from sewage treatment works (STW) in the catchment. Stepped combustion radiocarbon (SCR) measurements established that lake sediment contains between 11% (~ 1929 CE) and 69% (~ 1978 CE) recalcitrant carbon, with changes in carbon character coinciding with peaks in accumulation rate and linked to STW inputs. Catchment disturbance was identified by radiocarbon analysis, and included STW construction in the 1930s, determined using SCR analysis, and recent nearby highway construction, determined by measurements on dissolved organic carbon from the lake and outflow river. The quantity of autochthonous carbon buried was related to diatom biovolume accumulation rate (DBAR) and decreased when diatom accumulation rate and valve size declined, despite an overall increase in net carbon production. HPLC pigment analysis indicated that changes in total C deposition and diatom accumulation were related to proliferation of non-siliceous algae. HPLC results also indicated that dominance of recalcitrant carbon in sediment organic carbon was likely caused by increased deposition rather than preservation factors. The total algal accumulation rate controlled the sediment organic carbon accumulation rate, whereas DBAR was correlated to the proportion of each carbon source buried.
