Salinity Induced Regime Shift in Shallow Brackish Lagoons

Søndergaard, Martin; Pedersen, Asger Roer; Jürgens, Klaus; Strzelczak, Agnieszka; Lauridsen, Torben L.; Johansson, Liselotte S.

doi:10.1007/s10021-006-9007-6

Cited by 122 publications

(89 citation statements)

References 42 publications

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“…Later, after the hatching of individuals of this species from the eggs present in the sediments and despite the high amount of nutrients, the concentration of chlorophyll-a fell virtually to levels that characterize oligotrophic environments, resulting in a high transparency of the water. This could be because D. menucoensis belongs to a genus characterized by being the main grazer in aquatic ecosystems and given its filtration efficiency, prevents the development of high phytoplankton biomass, favors the growth of rooted vegetation, and leads to the establishment of a clear state, with high water transparency (Jeppesen et al, 1994(Jeppesen et al, , 2007Scheffer, 1998).…”

Section: Discussionmentioning

confidence: 99%

Zooplankton diversity and its relationship with environmental changes after the filling of a temporary saline lake in the semi-arid region of La Pampa Argentina

Vignatti¹,

Paggi²,

Cabrera³

et al. 2012

lajar

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ABSTRACT. Temporary water bodies can remain active as such for varying periods. However, they are reservoirs (as "egg banks") of species adapted to these special conditions. In central Argentina, there are numerous temporary lakes, which have only recently begun to be studied. The aim of this work was to describe the succession of changes in diversity, abundance and biomass of zooplankton as well as in the environment, over a period of eleven months, as from the filling of a temporary saline lake, and test the hypothesis that i) salinity affects negatively the richness and abundance but positively the biomass, and ii) due to changes in environmental conditions produced by advancing the hydroperiod, different species emerge from the egg bank at different times. At the beginning, when salinity was reduced and the concentration of chlorophyll-a was higher, we recorded the highest diversity, due mainly by less tolerance species. Later, as salinity increased, the macrophyta Ruppia cirrhosa developed and covered 90% of the surface of the lake, the concentration of chlorophyll-a decreased and the water transparency increased. The zooplankton richness decreased and the community was integrated only by halotolerant species. In the first two months, there was an increased replacement of species, indicated by the high value of Whittaker's beta diversity index (0.63), the density was high, with a predominance of microzooplankton, so the registered biomass was relatively reduced. Then, abundance decreased markedly, and was mostly dominated by macrozooplankton, so the biomass increased. When salinity exceeded 11 g L -1 , there was a predominance of the halophilic cladoceran Daphnia menucoensis, a species of ecological importance because it's high grazing pressure on phytoplankton. In this study, in addition to the modulating effect of salinity on the richness, abundance and zooplankton biomass, it was verified that the diversity present in the egg bank of temporary saline lakes is higher than that recorded in the water column at any time during hydrophases. Keywords: temporary lakes, saline lakes, Daphnia menucoensis, egg bank, central Argentina.Diversidad zooplanctónica y su relación con cambios ambientales luego del llenado de una laguna salina temporaria de la región semiárida de La Pampa, Argentina RESUMEN. Los cuerpos de agua temporarios pueden permanecer activos durante períodos variables, pero son reservorios ("bancos de huevos") de especies adaptadas a estas especiales condiciones. En el centro de Argentina existen numerosos lagos temporarios, que sólo recientemente han comenzado a ser estudiados. El objetivo de este trabajo fue describir la sucesión de cambios en la diversidad, abundancia y biomasa de zooplancton y en los parámetros ambientales, durante once meses, a partir del llenado de un lago salino temporario y probar las hipótesis de que i) la salinidad afecta negativamente la riqueza y abundancia pero positivamente a la biomasa y ii) debido a los cambios ambientales producidos al avanzar el hidroperíodo, difer...

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Section: Discussionmentioning

confidence: 99%

Zooplankton diversity and its relationship with environmental changes after the filling of a temporary saline lake in the semi-arid region of La Pampa Argentina

Vignatti¹,

Paggi²,

Cabrera³

et al. 2012

lajar

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“…Some studies have reported a shift in lake status from a clear-water macrophyte-dominated to a turbid algal-dominated state with increasing salinity (Davis et al, 2003;James et al, 2003;Jeppesen et al, 2007;Barker et al, 2008). This shift in lake ecological quality may be due to the direct adverse effects of salinity on aquatic plants (Davis et al, 2003;Barker et al, 2008) or to salinity-induced changes in trophic structure Barker et al, 2008) such as a shift in zooplankton size structure towards dominance of smaller and less efficient grazer species.…”

Section: Effects Of Changes In Salinity/conductivitymentioning

confidence: 99%

“…This may ultimately lead to reduced control of phytoplankton biomass Barker et al, 2008), or it may induce an increase in salt-tolerant periphyton, thereby reducing the light availability for plants (Barker et al, 2008). For example, in brackish lakes, Jeppesen et al (2007) found a strong regime shift from clear to turbid between 6 and 8% salinities. Additionally, with increasing salinity, the higher abundances of small planktivorous fish (e.g.…”

Section: Effects Of Changes In Salinity/conductivitymentioning

confidence: 99%

“…Prolonged hydraulic residence times resulting from drought also enhance salinization (Beklioglu et al, 2007;Beklioglu et al, 2011). Increased salinity not only favours cyanobacteria blooms (Sellner et al, 1988) but may also cause a ionic imbalance in saltsensitive taxa, resulting in ion toxicity and osmotic stress accompanied by high mortality or lower reproduction and growth rates (Nielsen et al, 2003;Jeppesen et al, 2007;Bezirci et al, 2012). Such conditions can significantly reduce the resilience of lake ecosystems or even induce a state shift to turbid water Barker et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

et al. 2015

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According to the Intergovernmental Panel on Climate Change report released in September 2014, unprecedented changes in temperature and precipitation patterns have been recorded globally in recent decades and further change is predicted to occur in the near future, mainly as the result of human activity. In particular, projections show that the Mediterranean climate zone will be markedly affected with significant implications for lake water levels and salinity. This may be exacerbated by increased demands for irrigation water. Based on long-term data from seven lakes and reservoirs covering a geographical gradient of 52°of latitudes and a literature review, we discuss how changes in water level and salinity related to climate change and water abstraction affect the ecosystem structure, function, biodiversity and ecological state of lakes and reservoirs. We discuss mitigation measures to counteract the negative effects on ecological status that are likely to result from changes in climate and water abstraction practices. Finally, we highlight research required to improve knowledge of the impacts of anthropogenically induced changes on lake water level and consequent changes in salinity.

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“…In contrast, conditions in coastal habitats such as lagoons and estuaries are highly variable, including changing salinities and subsequent changes in prey composition (e.g., [8,29,42,61,64]). Small waterbodies and low water depths are typical for such areas, leading to strong short-term changes in temperature during spring time (e.g., [24,52]), potentially with qualitative and quantitative implications for prey availability [2].…”

Section: Open Accessmentioning

confidence: 99%

Food-limited growth of larval Atlantic herring Clupea harengus recurrently observed in a coastal nursery area

Paulsen

Clemmesen

Hammer³

et al. 2016

Helgol Mar Res

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Food-limited growth of larval fish, defined as growth rates lower than observed in other habitats or from laboratory experiments at a given temperature, is rarely reported in field studies. This would imply that either larval fishes are living in an environment characterized by plenty of food, that nutritional condition selective mortality (i.e., eliminating the weak) is very strong, or this impression is caused by misinterpretation of data concerning e.g., poor taxonomical resolution of potential prey items, i.e., total potential prey abundance is high, but positively selected food is actually scarce. We analyzed RNA:DNA derived growth rates of herring larvae (Clupea harengus L.) and taxonomically differentiated prey field data of six consecutive spring seasons from the Kiel Canal, an artificial waterway in northern Germany, in order to test if food-limited growth in larval fish can occur recurrently in coastal habitats. In all years analyzed, larval growth rates decreased simultaneously with prey abundance at the end of each larval season. Furthermore, larval growth rates were observed to be lower than mean growth rates observed in another herring larvae nursery area at temperatures above 15 °C. Asymptotic relationships between prey abundance and larval growth rates were observed, further supporting the hypothesis of food-limitation. As larval growth was best explained by the abundance of the numerically dominant calanoid copepod Eurytemora affinis, the paramount importance of the dominant prey item is highlighted. We conclude that food limitation can be a severe and re-occurring issue for larval fish in coastal habitats, and that certain prey items play a crucial role in determining larval growth rates, and therefore potentially recruitment.

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Salinity Induced Regime Shift in Shallow Brackish Lagoons

Cited by 122 publications

References 42 publications

Zooplankton diversity and its relationship with environmental changes after the filling of a temporary saline lake in the semi-arid region of La Pampa Argentina

Zooplankton diversity and its relationship with environmental changes after the filling of a temporary saline lake in the semi-arid region of La Pampa Argentina

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

Food-limited growth of larval Atlantic herring Clupea harengus recurrently observed in a coastal nursery area

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