Factors controlling long-term changes of the eutrophicated ecosystem of Pärnu Bay, Gulf of Riga

Kotta, Jonne; Simm, Mart; Kotta, Ilmar; Kanošina, Inga; Kallaste, Kalle; Raid, Tiit

doi:10.1007/978-94-017-0920-0_24

Cited by 27 publications

(24 citation statements)

References 12 publications

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“…These species constitute ∼90% of the zooplankton consumed by herring in the GoR (38). The invasive cladoceran Cercopagis pengoi, occurring in our samples since 1997, was not included because of its potential multiple effects on different trophic levels, which may confound the analyses and make the interpretation of the results difficult: C. pengoi is prey for herring and a predator of other zooplankton species, which are in turn prey for herring and predators of phytoplankton (39,40). However, the structural changes in the GoR ecosystem started before the appearance of this plankter in our time series.…”

Section: Methodsmentioning

confidence: 99%

Predator transitory spillover induces trophic cascades in ecological sinks

Casini

Blenckner²,

Möllmann³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

102

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Understanding the effects of cross-system fluxes is fundamental in ecosystem ecology and biological conservation. Source-sink dynamics and spillover processes may link adjacent ecosystems by movement of organisms across system boundaries. However, effects of temporal variability in these cross-system fluxes on a whole marine ecosystem structure have not yet been presented. Here we show, using 35 y of multitrophic data series from the Baltic Sea, that transitory spillover of the top-predator cod from its main distribution area produces cascading effects in the whole food web of an adjacent and semi-isolated ecosystem. At varying population size, cod expand/contract their distribution range and invade/retreat from the neighboring Gulf of Riga, thereby affecting the local prey population of herring and, indirectly, zooplankton and phytoplankton via top-down control. The Gulf of Riga can be considered for cod a "true sink" habitat, where in the absence of immigration from the source areas of the central Baltic Sea the cod population goes extinct due to the absence of suitable spawning grounds. Our results add a metaecosystem perspective to the ongoing intense scientific debate on the key role of top predators in structuring natural systems. The integration of regional and local processes is central to predict species and ecosystem responses to future climate changes and ongoing anthropogenic disturbances.ecosystem regulation | predator distribution | landscape ecology | exploited resources | cross-system management

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Section: Methodsmentioning

confidence: 99%

Predator transitory spillover induces trophic cascades in ecological sinks

Casini

Blenckner²,

Möllmann³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

102

View full text Add to dashboard Cite

show abstract

“…30]. Besides, eutrophication deteriorates underwater light conditions and therefore further reduces overall biological diversity as in such a low-light environment only a few algal and associated invertebrate species can be found [34]. Consequently, an inverse relationship between eutrophication and CH is expected.…”

Section: Discussionmentioning

confidence: 99%

Role of physical water properties and environmental disturbances on the diversity of coastal macrophyte and invertebrate communities in a brackish water ecosystem

Kotta

Orav‐Kotta

Pärnoja

2013

WIT Transactions on Ecology and the Environment

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Biodiversity is important in maintaining ecosystem viability and the knowledge on how biodiversity is regulated and maintained is a prerequisite for the sustainable management of natural resources. Using three different diversity indices (macrozoobenthos community index, number of functional traits, community heterogeneity), we evaluated the role of physical water properties (water temperature, salinity, and velocity), coastal topography (depth and coastal slope), ice scouring (ice cover and duration) and eutrophication (water transparency, phytoplankton biomass) on benthic macrophyte and invertebrate communities in a brackish water ecosystem of the Baltic Sea. The analyses were performed at multiple spatial scales in order to identify scale-dependent relationships between the environment and biota as well as to promote our understanding of the patterns of macroalgal and invertebrate diversity in the coastal seascapes. The studied indices responded well to the changes in ambient environment and the links between environmental variables and indices were always the strongest at 5 km spatial scale. In general ice conditions, coastal topography and eutrophication had the strongest and physical water properties had the weakest effect to the studied indices. The eutrophication induced effects were the strongest at seascape scales and these are the scales at which the impacts of eutrophication on coastal biota should be assessed.

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“…Succession of phytoplankton starts at the end of March and ends in the first half of June. Summer succession starts in the middle of June and ends in the middle of September [18]. Due to low salinity and uniformity of habitat, the number of benthic invertebrate species is low.…”

Section: Methodsmentioning

confidence: 99%

Bayesian inference for predicting ecological water quality under different climate change scenarios

Kotta

Aps

Orav‐Kotta

2009

WIT Transactions on Ecology and the Environment

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The aim of this paper is to assess the separate and interactive effects of eutrophication and climate variables on the sea water quality in Pärnu Bay (the Gulf of Riga, Baltic Sea) using multivariate statistical analyses and the Bayesian Belief Network (BBN) methodology. The assessment was based on the following biological quality elements: phytoplankton, submerged aquatic vegetation and benthic invertebrates. The multivariate statistical analyses suggest that zoobenthos communities are largely driven by weather conditions (i.e. climate variables), phytoplankton by nutrient loads while the dynamics of macrophyte communities was due to the combined effect of weather and nutrient loads. The BBN constructed for this study represents uncertainty in ecological water quality assessment. Probabilistic modeling shows that phytoplankton and zoobenthos are not sensitive to climate change impacts while phytobenthos would suffer from decrease in sea water salinity. Under climate change, therefore, phytobenthos is one of the key variables in determining the water quality in the study area.

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Factors controlling long-term changes of the eutrophicated ecosystem of Pärnu Bay, Gulf of Riga

Cited by 27 publications

References 12 publications

Predator transitory spillover induces trophic cascades in ecological sinks

Predator transitory spillover induces trophic cascades in ecological sinks

Role of physical water properties and environmental disturbances on the diversity of coastal macrophyte and invertebrate communities in a brackish water ecosystem

Bayesian inference for predicting ecological water quality under different climate change scenarios

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