Phytoplankton as indicators for eutrophication in Europe's regional seas

Eutrophication of marine and coastal waters is a growing concern throughout Europe's regional seas and an historical problem in the Black Sea and regions of the North-East Atlantic, particularly the North Sea. As the base of the marine pelagic food web, phytoplankton are sensitive indicators of environmental change and therefore may be used as indicators of eutrophication for the monitoring, management and mitigation of the effects of nutrient loading on coastal and marine ecosystems. However, due to the interactive effects of climate and eutrophication, it can be difficult to separate the climatedriven response of phytoplankton from changes induced by excess nutrients. Therefore, the aim of this work is to separate these two signals in order to explore eutrophication effects. Without historical knowledge of 'pristine' or unimpacted ecosystem states it is difficult to identify and assess the severity and magnitude of change. Even w~re spatially and temporally comprehensive ecological datasets are available, equivalent nutrient timeseries are rare and a method of linking phytoplankton dynamics to eutrophication is required. Because open sea ecosystems are less impacted by anthropogenic nutrients than those near shore, offshore regions may be used as reference areas in comparison with coastal systems to investigate the effects of nutrient loading. Changes observed solely in coastal systems are mo$1likely a result of local processes (such as eutrophication) while those observed in both open sea and coastal areas are probably a response to large-scale drivers (such as climate). Therefore the comparison of coastal and open sea data may reveal different (or similar) patterns ofchange in phytoplankton indicators. Throughout most of the North-East Atlantic climate appears to override the effects of nutrients on phytoplankton dynamics, although the two drivers have been found to have synergistic effects resulting in increasing chlorophyll levels in the coastal North Sea. Additionally, the 1980s North-East Atlantic regime shift is clearly visible in coastal and open sea chlorophyll concentrations and diatom and' dinoflagellate abundances, demonstrating the sensitivity of phytoplankton as indicators at both the biomass and functional group scales. In the Black Sea, an observed decrease in chlorophyll appears to be at least partially a result of changes in climate and is not solely attributable to the 'recovery' of the Black Sea ecosystem. Black Sea chlorophyll has also undergone a possible recent (2002) regime shift, although its significance is difficult to determine due to the short time-series of chlorophyll data available. . The successful use of phytoplankton as indicators of eutrophication in these two disparate sea regions at two different ecological scales suggests that the method of comparing coastal and open sea phytoplankton data could be applied to other European seas as a means of distinguishing betWeen the effects of climate and eutrophication.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

mNCEA policy brief - The many scales of pelagic habitats

This fact sheet is intended to help explain the extreme variation in both abundance and body size exhibited by marine plankton and why those characteristics make them challenging to understand. Plankton in pelagic (open ocean) habitats vary greatly in abundance and body size, presenting significant challenges for assessing the state of pelagic habitats. There are also vast differences in the spatial and temporal scale of events and pressures impacting pelagic habitats, adding complexity and making pelagic habitats challenging to understand. This project was funded by the Department for Environment, Food and Rural Affairs (Defra) as part of the marine arm of the Natural Capital and Ecosystem Assessment (NCEA) programme. The marine NCEA programme is leading the way in supporting Government ambition to integrate natural capital approaches into decision making for the marine environment. Find out more at https://www.gov.uk/government/publications/natural-capital-and-ecosystem-assessment-programme

Non-linearities, regime shifts and recovery: The recent influence of climate on Black Sea chlorophyll

The Black Sea ecosystem experienced severe eutrophication-related degradation during the 1970s and 1980s. However, in recent years the Black Sea has shown some signs of recovery which are often attributed to a reduction in nutrient loading. Here, SeaWiFS chlorophyll a (chl a), a proxy for phytoplankton biomass, is used to investigate spatio-temporal patterns in Black Sea phytoplankton dynamics and to explore the potential role of climate in the Black Sea's recovery. Maps of chl a anomalies, calculated relative to the 8 year mean, emphasize spatial and temporal variability of phytoplankton biomass in the Black Sea, particularly between the riverine-influenced Northwest Shelf and the open Black Sea. Evolution of phytoplankton biomass has shown significant spatial variability of persistence of optimal bloom conditions between three major regions of the Black Sea. With the exception of 2001, chl a has generally decreased during our 8 year time-series. However, the winter of 2000-2001 was anomalously warm with low wind stress, resulting in reduced vertical mixing of the water column and retention of nutrients in the photic zone. These conditions were associated with anomalously high levels of chl a throughout much of the open Black Sea during the following spring and summer. The unusual climatic conditions occurring in 2001 may have triggered a shift in the Black Sea's chl a regime. The long-term significance of this recent shift is still uncertain but illustrates a non-linear response to climate forcing that makes future ecosystem changes in the pelagic Black Sea ecosystem difficult to predict. © 2008 Elsevier B.V. All rights reserved

The Continuous Plankton Recorder survey: how can long-term phytoplankton datasets contribute to the assessment of Good Environmental Status?

Phytoplankton are crucial to marine ecosystem functioning and are important indicators of environmental change. Phytoplankton data are also essential for informing management and policy, particularly in supporting the new generation of marine legislative drivers, which take a holistic ecosystem approach to management. The Marine Strategy Framework Directive (MSFD) seeks to achieve Good Environmental Status (GES) of European seas through the implementation of such a management approach. This is a regional scale directive which recognises the importance of plankton communities in marine ecosystems; plankton data at the appropriate spatial, temporal and taxonomic scales are therefore required for implementation. The Continuous Plankton Recorder (CPR) survey is a multidecadal, North Atlantic–basin scale programme which routinely records approximately 300 phytoplankton taxa. Because of these attributes, the survey plays a key role in the implementation of the MSFD and the assessment of GES in the Northeast Atlantic region. This paper addresses the role of the CPR's phytoplankton time-series in delivering GES through the development and informing of MSFD indicators, the setting of targets against a background of climate change and the provision of supporting information used to interpret change in non-plankton indicators. We also discuss CPR data in the context of other phytoplankton data types that may contribute to GES, as well as explore future possibilities for the use of new and innovative applications of CPR phytoplankton datasets in delivering GES. Efforts must be made to preserve long-term time series, such as the CPR, which supply vital ecological information used to informed evidence-based environmental policy

A century of change in North Sea plankton communities explored through integrating historical datasets

Full text embargoed until 12.10.2019 (publisher's embargo period, 12 months

Long-Term Trends in Calcifying Plankton and pH in the North Sea

Relationships between six calcifying plankton groups and pH are explored in a highly biologically productive and data-rich area of the central North Sea using time-series datasets. The long-term trends show that abundances of foraminiferans, coccolithophores, and echinoderm larvae have risen over the last few decades while the abundances of bivalves and pteropods have declined. Despite good coverage of pH data for the study area there is uncertainty over the quality of this historical dataset; pH appears to have been declining since the mid 1990s but there was no statistical connection between the abundance of the calcifying plankton and the pH trends. If there are any effects of pH on calcifying plankton in the North Sea they appear to be masked by the combined effects of other climatic (e.g. temperature), chemical (nutrient concentrations) and biotic (predation) drivers. Certain calcified plankton have proliferated in the central North Sea, and are tolerant of changes in pH that have occurred since the 1950s but bivalve larvae and pteropods have declined. An improved monitoring programme is required as ocean acidification may be occurring at a rate that will exceed the environmental niches of numerous planktonic taxa, testing their capacities for acclimation and genetic adaptation

Implications of taxon-level variation in climate change response for interpreting plankton lifeform biodiversity indicators

Abstract Indicators based on broad functional characteristics, which group plankton taxa into “lifeforms”, summarize changes across a high number of taxa in a way that reflects changes in community functioning and are used to inform policy assessments. Key questions remain, however, as to what extent plankton taxa within these lifeforms share responses to environmental change. Addressing this knowledge gap can provide additional information on the influence of environmental drivers, including climate change, on plankton communities. Here, we use a multi-decadal plankton time series to examine the extent to which taxa within lifeforms share responses to sea surface temperature (SST) change. At the North Sea scale, the individual taxa responses within the dinoflagellate lifeform are skewed towards a negative response to increasing SST, consolidating previous findings that dinoflagellate abundance is decreasing with ocean warming. The individual taxa responses within the zooplankton lifeforms, however, varied, suggesting that lifeform traits are less of a factor determining response to SST for zooplankton than for phytoplankton. The lifeform level of grouping taxa, therefore, is useful for communicating change in the state and functioning of ecosystems, but finer taxonomically resolved data are essential for determining the drivers of plankton community change, including climate influences, during formal assessments.</jats:p

Are plankton nets a thing of the past? An assessment of in situ imaging of zooplankton for large-scale ecosystem assessment and policy decision-making

Zooplankton are fundamental to aquatic ecosystem services such as carbon and nutrient cycling. Therefore, a robust evidence base of how zooplankton respond to changes in anthropogenic pressures, such as climate change and nutrient loading, is key to implementing effective policy-making and management measures. Currently, the data on which to base this evidence, such as long time-series and large-scale datasets of zooplankton distribution and community composition, are too sparse owing to practical limitations in traditional collection and analysis methods. The advance of in situ imaging technologies that can be deployed at large scales on autonomous platforms, coupled with artificial intelligence and machine learning (AI/ML) for image analysis, promises a solution. However, whether imaging could reasonably replace physical samples, and whether AI/ML can achieve a taxonomic resolution that scientists trust, is currently unclear. We here develop a roadmap for imaging and AI/ML for future zooplankton monitoring and research based on community consensus. To do so, we determined current perceptions of the zooplankton community with a focus on their experience and trust in the new technologies. Our survey revealed a clear consensus that traditional net sampling and taxonomy must be retained, yet imaging will play an important part in the future of zooplankton monitoring and research. A period of overlapping use of imaging and physical sampling systems is needed before imaging can reasonably replace physical sampling for widespread time-series zooplankton monitoring. In addition, comprehensive improvements in AI/ML and close collaboration between zooplankton researchers and AI developers are needed for AI-based taxonomy to be trusted and fully adopted. Encouragingly, the adoption of cutting-edge technologies for zooplankton research may provide a solution to maintaining the critical taxonomic and ecological knowledge needed for future zooplankton monitoring and robust evidence-based policy decision-making