Functional shifts in estuarine zooplankton in response to climate variability

Jansson, Anna; Klais-Peets, Riina; Grinienė, Evelina; Rubene, Gunta; Семенова, А. С.; Lewandowska, Aleksandra M.; Engström‐Öst, Jonna

doi:10.1002/ece3.6793

Cited by 18 publications

(13 citation statements)

References 74 publications

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“…Changes in zooplankton functional groups, such as a shift from raptorial and suspension-feeding copepods and cladocerans to a dominance of small filter-feeding rotifers and cladocerans, have also been shown as results of warming (Suikkanen et al, 2013;Jansson et al, 2020). OA also promoted the growth of suspension-feeding cladocerans because of a CO 2 -driven increase in cyanobacteria (Lischka et al, 2017).…”

Section: Mesozooplanktonmentioning

confidence: 99%

“…In areas where climate change increases the supply of allochthonous DOM into the system, and where increasing stratification reduces the transport of nutrients from deeper waters, phytoplankton production may decline and the trophic pathways from bacteria and flagellates through ciliates to copepods may strengthen (Aberle et al, 2015). When the system shifts towards heterotrophy, the food web efficiency declines (Båmstedt and Wikner, 2016), and if zooplankton also becomes dominated by smaller-sized plankton (Dahlgren et al, 2011;Suikkanen et al, 2013;Jansson et al, 2020), there will be less suitable food available for planktivorous fish. If sedimentation of organic matter will also be reduced, zoobenthos production will decrease and there will be less food for benthic-eating fish.…”

Section: Trophic Efficiency and Consequences To The Secondary Productionmentioning

confidence: 99%

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Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Viitasalo

Bonsdorff

2022

Earth Syst. Dynam.

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Abstract. Climate change has multiple effects on Baltic Sea species, communities and ecosystem functioning through changes in physical and biogeochemical environmental characteristics of the sea. Associated indirect and secondary effects on species interactions, trophic dynamics and ecosystem function are expected to be significant. We review studies investigating species-, population- and ecosystem-level effects of abiotic factors that may change due to global climate change, such as temperature, salinity, oxygen, pH, nutrient levels, and the more indirect biogeochemical and food web processes, primarily based on peer-reviewed literature published since 2010. For phytoplankton, clear symptoms of climate change, such as prolongation of the growing season, are evident and can be explained by the warming, but otherwise climate effects vary from species to species and area to area. Several modelling studies project a decrease of phytoplankton bloom in spring and an increase in cyanobacteria blooms in summer. The associated increase in N:P ratio may contribute to maintaining the “vicious circle of eutrophication”. However, uncertainties remain because some field studies claim that cyanobacteria have not increased and some experimental studies show that responses of cyanobacteria to temperature, salinity and pH vary from species to species. An increase of riverine dissolved organic matter (DOM) may also decrease primary production, but the relative importance of this process in different sea areas is not well known. Bacteria growth is favoured by increasing temperature and DOM, but complex effects in the microbial food web are probable. Warming of seawater in spring also speeds up zooplankton growth and shortens the time lag between phytoplankton and zooplankton peaks, which may lead to decreasing of phytoplankton in spring. In summer, a shift towards smaller-sized zooplankton and a decline of marine copepod species has been projected. In deep benthic communities, continued eutrophication promotes high sedimentation and maintains good food conditions for zoobenthos. If nutrient abatement proceeds, improving oxygen conditions will first increase zoobenthos biomass, but the subsequent decrease of sedimenting matter will disrupt the pelagic–benthic coupling and lead to a decreased zoobenthos biomass. In the shallower photic systems, heatwaves may produce eutrophication-like effects, e.g. overgrowth of bladderwrack by epiphytes, due to a trophic cascade. If salinity also declines, marine species such as bladderwrack, eelgrass and blue mussel may decline. Freshwater vascular plants will be favoured but they cannot replace macroalgae on rocky substrates. Consequently invertebrates and fish benefiting from macroalgal belts may also suffer. Climate-induced changes in the environment also favour establishment of non-indigenous species, potentially affecting food web dynamics in the Baltic Sea. As for fish, salinity decline and continuing of hypoxia is projected to keep cod stocks low, whereas the increasing temperature has been projected to favour sprat and certain coastal fish. Regime shifts and cascading effects have been observed in both pelagic and benthic systems as a result of several climatic and environmental effects acting synergistically. Knowledge gaps include uncertainties in projecting the future salinity level, as well as stratification and potential rate of internal loading, under different climate forcings. This weakens our ability to project how pelagic productivity, fish populations and macroalgal communities may change in the future. The 3D ecosystem models, food web models and 2D species distribution models would benefit from integration, but progress is slowed down by scale problems and inability of models to consider the complex interactions between species. Experimental work should be better integrated into empirical and modelling studies of food web dynamics to get a more comprehensive view of the responses of the pelagic and benthic systems to climate change, from bacteria to fish. In addition, to better understand the effects of climate change on the biodiversity of the Baltic Sea, more emphasis should be placed on studies of shallow photic environments. The fate of the Baltic Sea ecosystem will depend on various intertwined environmental factors and on development of the society. Climate change will probably delay the effects of nutrient abatement and tend to keep the ecosystem in its “novel” state. However, several modelling studies conclude that nutrient reductions will be a stronger driver for ecosystem functioning of the Baltic Sea than climate change. Such studies highlight the importance of studying the Baltic Sea as an interlinked socio-ecological system.

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Section: Mesozooplanktonmentioning

confidence: 99%

Section: Trophic Efficiency and Consequences To The Secondary Productionmentioning

confidence: 99%

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Viitasalo

Bonsdorff

2022

Earth Syst. Dynam.

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“…This suggests that the projected OAW may affect the populations of these dominant copepods in the coming decades. Subtle effects on zooplankton functional groups, such as a shift to a dominance by cladocerans and rotifers, have also been shown as a result of warming (Jansson et al, 2020), and it seems likely that the zooplankton community will undergo significant change as climateinduced warming and reduced salinity continues.…”

Section: Zooplanktonmentioning

confidence: 99%

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Viitasalo

Bonsdorff

2021

Preprint

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Abstract. Climate change has multiple direct and indirect potentially synergistic effects on Baltic Sea species, organism communities, and on ecosystem functioning, through physical and biogeochemical environmental characteristics of the sea. Associated indirect and secondary effects on species interactions, trophic dynamics and ecosystem function are expected to be significant. Evidence on effects of climate are compiled from and reviewed for field studies, experimental work, as well as modelling studies primarily from published literature after 2010. The responses vary within and between species groups, even between sibling species. Such subtle differences, as well as secondary feedbacks and altered trophic pathways, make projections difficult. Some common patterns arise from the wealth of recent studies, however. It is likely that the combined effects of increased external nutrient loads, stratification and internal loading will improve the conditions for cyanobacterial blooms in large parts of the Baltic. In the northernmost areas the increasing allochtonous DOM may further complicate the picture by increasing heterotrophy and by decreasing food web efficiency. This effect may, however, be counteracted by the intensification of the bacteria-flagellate-microzooplankton-mesozooplankton link, which may change the system from a bottom-up controlled one to a top-down controlled one. In deep benthic communities, continued eutrophication may promote higher sedimentation of organic matter and increase zoobenthic biomasses, but eventually increasing stratification and hypoxia/anoxia will disrupt benthic-pelagic coupling, leading to reduced benthic biomass. In the photic benthic systems warmer winters with less ice and nutrient increase enhances eutrophication. The projected salinity decline suppresses marine species, and temperature increase overgrowth of perennial macroalgae by annual filamentous alga throughout the growing-season, and major changes in the marine entire ecosystem are expected. The changes in environmental conditions probably also lead to increased establishment of non-indigenous species, potentially affecting food web dynamics in large areas of the Baltic Sea. However, several modelling studies have concluded that nutrient reductions according to the Baltic Sea Action Plan of Helsinki Commission may be a stronger driver for ecosystem functions in the Baltic Sea than climate change. Such studies highlight the importance of studying the Baltic Sea as an interlinked socio-ecological system. Knowledge gaps include uncertainties in projecting the future salinity level as well as stratification under different climate forcings. This weakens our ability to project how overall biodiversity, pelagic productivity, fish populations, and macroalgal communities may change in the future. Experimental work must be better integrated into studies of food web dynamics, to get a more comprehensive view of the responses of the pelagic and benthic systems to climate change, from bacteria to fish. Few studies have holistically investigated the shallow water ecosystems holistically. There are complex climate-induced interactions and multiple feedbacks between algae, grazers and their predators, that are poorly known, as are the effects of non-native invasive species. Finally, both 2D species distribution models and 3D ecosystem models could benefit from better integration of approaches including physical, chemical and biological parameters.

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“…No trend was detected after that (HELCOM, 2009). The latest monitoring data are not analyzed for long-term trends and inter-annual variations in near-bottom oxygen concentrations; instead, model outcomes are used to describe the oxygen conditions (e.g., Jansson et al, 2020). However, it is well documented that the anoxic and hypoxic areas have been expanding in the entire Baltic Sea during the last decades due to both eutrophication and the changes in climatic conditions (Hansson and Viktorsson, 2020; the analysis also includes data from the Gulf of Riga).…”

Section: Introductionmentioning

confidence: 99%

Causes of the extensive hypoxia in the Gulf of Riga in 2018

Stoicescu

Laanemets

Liblik

et al. 2021

Preprint

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Abstract. The Gulf of Riga is a relatively shallow bay connected to the deeper central Baltic Sea (Baltic Proper) via straits with sills. The decrease in the near-bottom oxygen levels from spring to autumn is a common feature in the gulf, but in 2018, hypoxia was exceptional. We analyzed temperature, salinity, oxygen, and nutrient data collected in 2018 and historical data available from environmental databases. Forcing data from the study year were compared with their long-term means and variability. The year 2018 was exceptional due to occasionally dominating north-easterly winds supporting the inflow of saltier waters from the Baltic Proper and meteorological conditions causing fast development of thermal stratification in spring. Existing stratification hindered vertical transport between the near-bottom layer (NBL) and the water layers above it. The estimated oxygen consumption rate at the sediment surface in spring-summer 2018 was about 1.7 mmol O2 m−2 h−1 that exceeded the oxygen input to the NBL due to advection and mixing. We suggest that the observed pronounced oxygen depletion was magnified by the prolonged stratified season and haline stratification in the deep layer that maintained a decreased water volume between the seabed and the pycnocline. The observed increase in phosphate concentrations in the NBL in summer 2018 suggests a significant sediment phosphorus release in hypoxic conditions counteracting the mitigation measures to combat eutrophication. We conclude, if similar meteorological conditions as in 2018 could occur more frequently in the future, such extensive hypoxia would be more common in the Gulf of Riga and other coastal basins with similar morphology and human-induced elevated input of nutrients.

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Functional shifts in estuarine zooplankton in response to climate variability

Cited by 18 publications

References 74 publications

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Global climate change and the Baltic Sea ecosystem: direct and indirect effects on species, communities and ecosystem functioning

Causes of the extensive hypoxia in the Gulf of Riga in 2018

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