Major declines in NE Atlantic plankton contrast with more stable populations in the rapidly warming North Sea

Plankton form the base of marine food webs, making them important indicators of ecosystem status. Changes in the abundance of plankton functional groups, or lifeforms, can affect higher trophic levels and can indicate important shifts in ecosystem functioning. Here, we extend this knowledge by combining data from Continuous Plankton Recorder and fixed-point stations to provide the most comprehensive analysis of plankton time-series for the North-East Atlantic and North-West European shelf to date. We analysed 24 phytoplankton and zooplankton datasets from 15 research institutions to map 60-year abundance trends for 8 planktonic lifeforms. Most lifeforms decreased in abundance (e.g. dinoflagellates: −5 %, holoplankton: −7 % decade−1), except for meroplankton, which increased 12 % decade−1, reflecting widespread changes in large-scale and localised processes. K-means clustering of assessment units according to abundance trends revealed largely opposing trend direction between shelf and oceanic regions for most lifeforms, with North Sea areas characterised by increasing coastal abundance, while abundance decreased in North-East Atlantic areas. Individual taxa comprising each phytoplankton lifeform exhibited similar abundance trends, whereas taxa grouped within zooplankton lifeforms were more variable. These regional contrasts are counterintuitive, since the North Sea which has undergone major warming, changes in nutrients, and past fisheries perturbation has changed far less, from phytoplankton to fish larvae, as compared to the more slowly warming North-East Atlantic with lower nutrient supply and fishing pressure. This more remote oceanic region has shown a major and worrying decline in the traditional food web. Although the causal mechanisms remain unclear, declining abundance of key planktonic lifeforms in the North-East Atlantic, including diatoms and copepods, are a cause of major concern for the future of food webs and should provide a red flag to politicians and policymakers about the prioritisation of future management and adaptation measures required to ensure future sustainable use of the marine ecosystem

Emerging New Crop Pests: Ecological Modelling and Analysis of the South American Potato Psyllid Russelliana solanicola (Hemiptera: Psylloidea) and Its Wild Relatives

© 2017 Syfert et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The Plankton Lifeform Extraction Tool: a digital tool to increase the discoverability and usability of plankton time-series data

Abstract. Plankton form the base of the marine food web and are sensitive indicators of environmental change. Plankton time series are therefore an essential part of monitoring progress towards global biodiversity goals, such as the Convention on Biological Diversity Aichi Targets, and for informing ecosystem-based policy, such as the EU Marine Strategy Framework Directive. Multiple plankton monitoring programmes exist in Europe, but differences in sampling and analysis methods prevent the integration of their data, constraining their utility over large spatio-temporal scales. The Plankton Lifeform Extraction Tool brings together disparate European plankton datasets into a central database from which it extracts abundance time series of plankton functional groups, called “lifeforms”, according to shared biological traits. This tool has been designed to make complex plankton datasets accessible and meaningful for policy, public interest, and scientific discovery. It allows examination of large-scale shifts in lifeform abundance or distribution (for example, holoplankton being partially replaced by meroplankton), providing clues to how the marine environment is changing. The lifeform method enables datasets with different plankton sampling and taxonomic analysis methodologies to be used together to provide insights into the response to multiple stressors and robust policy evidence for decision making. Lifeform time series generated with the Plankton Lifeform Extraction Tool currently inform plankton and food web indicators for the UK's Marine Strategy, the EU's Marine Strategy Framework Directive, and for the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) biodiversity assessments. The Plankton Lifeform Extraction Tool currently integrates 155 000 samples, containing over 44 million plankton records, from nine different plankton datasets within UK and European seas, collected between 1924 and 2017. Additional datasets can be added, and time series can be updated. The Plankton Lifeform Extraction Tool is hosted by The Archive for Marine Species and Habitats Data (DASSH) at https://www.dassh.ac.uk/lifeforms/ (last access: 22 November 2021, Ostle et al., 2021). The lifeform outputs are linked to specific, DOI-ed, versions of the Plankton Lifeform Traits Master List and each underlying dataset. </jats:p

Assessing the state of marine biodiversity in the Northeast Atlantic

The Northeast Atlantic, a highly productive maritime area, has been exposed to a wide range of direct human pressures, such as fishing, shipping, coastal development, pollution, and non-indigenous species (NIS) introductions, in addition to anthropogenically-driven global climate change. Nonetheless, this regional sea supports a high diversity of species and habitats, whose functioning provides a variety of ecosystem services, essential for human welfare. In 2017, OSPAR, the Northeast Atlantic Regional Seas Commission, delivered an assessment of marine biodiversity for the Northeast Atlantic. This assessment examined biodiversity indicators separately to identify changes in Northeast Atlantic biodiversity, but stopped short of determining the status of biodiversity for many species and habitats. Here, we expand on this work and for the first time, a semi-quantitative approach is applied to evaluate holistically the state of Northeast Atlantic marine biodiversity across marine food webs, from plankton to top predators, via fish, pelagic and benthic habitats, including xeno-biodiversity (i.e. NIS). Our analysis reveals widespread degradation in marine ecosystems and biodiversity, particularly for marine birds and coastal bottlenose dolphins, as well as for benthic habitats and fish in some regions. The poor biodiversity status of these ecosystem components is likely the result of cumulative effects of human activities, such as habitat destruction or disturbance, overexploitation, eutrophication, the introduction of NIS, and climate change. Bright spots are also revealed, such as recent signs of recovery in some fish and marine bird communities and recovery in harbour and grey seal populations and the condition of coastal benthic communities in some regions. The status of many indicators across all ecosystem components, but particularly for the novel pelagic habitats, food webs and NIS indicators, however, remains uncertain due to gaps in data, unclear pressure-state relationships, and the non-linear influence of some pressures on biodiversity indicators. Improving monitoring and data access and increasing understanding of pressure-state relationships, including those that are non-linear, is therefore a priority for enabling future assessments, as is consistent and stable resourcing for expert involvement

Seasonal variability in microplanktonic biomasses in the Gironde dilution plume (Bay of Biscay): relative importance of bacteria

Bacterial and phytoplankton biomasses were estimated in a four-year study along a saline gradient (the dilution plume of the Gironde estuary on the Aquitanian continental shelf), by measuring bacterial abundance and mean cell volumes (epifluorescence counts) and chlorophyll-a concentrations tin vitro fluorescence). The spatial and temporal distribution of phytoplankton enabled us to determine the seasonal succession of algal blooms, sprouting in the marine waters of the inner shelf in early spring (picoplanktonic forms), reaching their annual maximum (10 mu g L-1) in plume waters in advanced spring, and moving to estuarine waters in the summer (> 20 mu m forms). Bacterial biomasses followed mainly a decreasing dilution gradient, especially in winter and early spring, with maximum estuarine values reaching 10(7) cell mL(-1) (more than 30 % of small attached cells and more than 60 % of free small cocci), in accordance with estuarine discharges into the inner shelf zone. Moreover, plume waters showed an additionnal peak of bacterial numbers and mean cell volumes in early summer, with increasing proportions of larger rod- and vibrio-shaped bacteria. A clear morphometrical succession was followed in marine waters, from a majority of attached and coccal cells in winter, to maximal proportions of larger vibrio-shaped bacteria, inducing a maximal spring level of total abundance (2 x 10(6) cell mL(-1)) and high mean cell volumes (0.044 mu m(3)), coinciding with the marine vernal bloom. Bacterial estimated biomass represented, consequently, a wide range of proportions compared to phytoplankton: only when a good correlation was found between them, bacterial-C/phytoplankton-C ratio was close to 1/4, a correlation that improved in warmer periods, throughout different water types. Due to the relavitely narrow range of chlorophyll-a values, we could not find a high predictive correlation when pooling all the 4-year data, a relationship that has been outlined in important reviews by pooling together different aquatic systems. We noticed, however, that in the particular environment of our study (high inputs of particulate detritic matter) bacterial-C usually dominated the microbial pool (specially in estuarine and plume waters and in light-limited conditions). This dominance, added to the frequent dominance of small-sized phytoplankton, leads to an enhanced "microbial loop" activity, defining a "maintenance system" (oligotrophic conditions), which alternates with some eutrophic periods.Les biomasses bactériennes et phytoplanctoniques ont été estimées au cours d'une étude menée sur quatre ans, le long d'un gradient halin (panache de dilution girondin, sur le plateau continental Aquitain), par des mesures globales d'abondances et biovolumes bactériens (comptages en épifluorescence) et par des mesures de chlorophylle-a (fluorimétrie extractive). La répartition spatio-temporelle des micro-algues nous a permis de préciser la succession spatiotemporelle de leurs poussées, depuis le début du printemps (formes picoplanctoniques) en eaux marines, vers une situation de poussée de panache (maximum annuel de 10 μg chl-a.L−1), puis vers la situation de poussée phytoplanctonique estivale (formes > 20 μm). Un gradient de dilution décroissant caractérise les biomasses bactériennes, spécialement en hiver et au début du printemps, les maxima estuariens atteignant les 107 cell.mL−1, 30 % de petites bactéries attachées, et plus de 60 % de formes coccoïdes libres. Les eaux de panache ont présenté un pic de biomasses à la transition printemps-été, avec encore 15 % de bactéries attachées, mais de fortes proportions en grandes formes libres (vibrioïdes et bâtonnets). En eaux marines, on décèle une succession morphométrique, avec une majorité de bactéries attachées et coccoïdes en hiver, alors que les formes libres vibrioïdes sont fortement représentées au printemps, provoquant, au moment du bloom algal, un niveau maximal d'abondances (2 × 106 cell.mL−1) et de volumes moyens cellulaires bactériens (0,044 μm3). L'importance relative des biomasses bactériennes par rapport au phytoplancton est par conséquent extrêmement variable, et la relation établie entre les deux stocks, lorsqu'elle existe, est d'autant plus significative que l'on avance dans la saison, le rapport moyen C-bact/C-phyto étant de Full-size image (<1 K). En raison du manque de représentativité des fortes concentrations chlorophylliennes dans cette étude, nous n'avons pas retrouvé la corrélation hautement significative décrite dans les synthèses bibliographiques, englobant un bon nombre de systèmes aquatiques. Nous avons toutefois remarqué que, dans cet environnement particulier (importants apports particulaires détritiques), le C-bactérien domine le plus souvent au sein du pool de biomasse microbienne (surtout en eaux dessalées, et lors des périodes de limitation par la lumière). Cette dominance bactérienne, ajoutée à la présence d'un phytoplancton de petites dimensions, dénote d'une activité accrue de la « boucle microbienne å, et permet de caractériser un système de « maintenance å (conditions oligotrophes), alternant au cours des saisons avec quelques périodes eutrophes

Role of the bacterial community in the annual benthic metabolism of two contrasted temperate intertidal sites (Roscoff Aber Bay, France)

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