Terms of Reference (2024-2026)

ToR A:  Developing size-based indicators of plankton status and energy transfer efficiency

Size is a "master trait" in pelagic ecosystems, dictating the pace of a wide range of processes ranging from individual cell to ecosystem in scale. By considering size as a central theme, zooplankton can be linked to phytoplankton and as a conduit, of highly variable efficiency, to commercially exploited fish. We will continue to compile a database of plankton sizes to be used in conjunction with zooplankton time series to provide a scoping report on suitable data for size spectra analysis. This report will list the availability of suitable time series of data that provide complete abundance and mass indices among taxa that span from nanoplankton up to macroplankton. These suitable datasets will enable the construction of size spectra which provide a simple and robust in-situ index of how efficiently energy is transferred from primary production up to organisms the size of fish. The size-based indicator developed originally for ecosystem status assessment in the Baltic Sea, will be used and expanded across suitable ICES sites across the Atlantic to understand how the changing size structure of the marine ecosystem relates to environmental conditions.

Preliminary contact points for ToR A:    Maiju Lehtiniemi, Jasmin Renz, Angus Atkinson, Sophie Pitois

ToR B:  Assessing patterns and trends of zooplankton community properties

Zooplankton community changes have been observed across the North Atlantic in recent decades, associated with changes in ocean circulation and environmental conditions (e.g., water column mixing, water temperature, phytoplankton bloom dynamics). This ToR characterises and compares long-term trends and patterns in community changes across ICES time series. Changes in mesozooplankton, macrozooplankton and gelatinous groups will be considered. Changes in rank-based assessment of community structure at the sites will be assessed in terms of species functional traits and biogeographic associations, and their association with changes in environmental conditions (e.g., depth, distance from shore, region). Tracking and understanding changes in zooplankton community composition across time series stations and at the basin scale has applications to understanding pelagic ecosystem dynamics and implications for marine resource management.

Preliminary contact points for ToR B: Catherine Johnson, Dafne Eerkes-Medrano

ToR C:  Report on the status and trends of plankton in the ICES North Atlantic and inland seas

In collaboration with WGPME, this revival of the legacy ICES Plankton Status Report series will create a hybrid online product of interactive exploration tools and summary text based on satellite and in-situ plankton and environmental data. Splitting the content of the massive Plankton Status Report into smaller geographic regions and shorter summary texts will facilitate easier and more frequent updates (e.g., every 1-2 years online versus every 3-5 years per report), providing more recent and relevant material to the community. This will build upon existing content (e.g. https://wgze.net/metabase, https://wgpme.net/metabase, https://igmets.net/explorer) and further expand it with new capabilities and tools. This work will also enable focused studies on key trends discovered in the general summary results, leading to special reports and/or peer-reviewed papers.

Preliminary contact points for ToR C:  Todd O'Brien

ToR D:  Models and data requirements to understand zooplankton trends

Through its members' zooplankton monitoring sites, WGZE has access to zooplankton time series across the North Atlantic, Mediterranean and Baltic Seas, and it produces the Zooplankton Status Report summarizing trends among regions and over time. Since 2015, joint WGZE-WGIPEM meetings have provided an opportunity to discuss common interests, including gaps in knowledge and data needs for modelling lower trophic levels. In 2023 WGIPEM presented to WGZE a list of zooplankton information and data that would be useful for modelling lower trophic level rate processes and food web linkage. WGZE is interested in a dialogue between zooplanktologists and modellers- (dialogue/joint ToR with WGIPEM) not only about data requirement for models but also about the kind of models that would be most suitable to understand the complexity of ecosystems and zooplankton trends in the context of climate change. In addition to consideration of the list that WGIPEM presented, recent recommendations in the literature about plankton modelling data requirements and applications (e.g. Grigoratou et al. 2022: Bull. Limnol. Oceanogr. 31(1): 22-26. https://doi.org/10.1002/lob.10479) will be assessed as next action steps for implementation.

Prelminary contact points for ToR D:  Antonina dos Santos (Rubao Ji, Jeff Runge)

ToR E:  Automated image analysis for zooplankton monitoring

Imaging is an increasingly common approach for sampling zooplankton and can provide new types of plankton data (e.g., continuous data as opposed to discrete, or in situ size). Each imaging instrument has individual characteristics, advantages and disadvantages, and each instrument produces slightly different types of images. New methods are required to harmonise data and intercalibrate between devices to determine how full advantage can be taken of system or suite of systems. A platform where information is collated on the instrument's description, its associated limitations and a record of captured images will be a useful tool to help selecting which instrument or combination of instruments are best suited for addressing specific ecological questions. The ecological insight obtained from these methods may enable answering long-standing ecological questions unanswerable with traditional methods. Canvassing experts in the field to detail these questions might provide guidance for how to best deploy these tools. A list will be drawn up with existing and new research questions that may be resolved by these instruments. As sampling becomes increasingly digital, it is prudent to ensure new time series or time series where methods are migrating to digital solutions, can be integrated into existing time series and repositories. These repositories exist (e.g. Copepod database, ICES data portal) but image data remains absent. Developing a pipeline that can be used to migrate existing image-based time series to online databases, following the FAIR principles, will result in increased data accessibility.

Preliminary contact points for ToR E:  James Scott, Elaine Fileman, and Sophie Pitois

ToR F:  Improving representation of under-surveyed macrozooplankton and non-crustacean taxa

Marine zooplankton is a diverse assemblage spanning 15 phyla and covering wide size spectra as well as several trophic niches from filter feeders to grazers and predators. Yet, zooplankton surveys are traditionally highly biased towards crustacean mesozooplankton, particularly the numerically dominant copepods, resulting in a relatively narrow representation of the existing phylogenetic, ecological, and functional diversity, and potentially missing ongoing changes concerning the other taxa. There are several reasons for this, such as methodological constraints in sampling, sample processing and preservation, subsampling practices resulting in a poor representation of the less numerous predatory species, lacking taxonomic expertise, and general down-prioritisation. With the marine systems facing rapid human-induced environmental changes, likely to result in altered structure and functioning of zooplankton communities, there is a need to expedite the accumulation of ecological and biodiversity data across the entire plankton community. ToR F contributes to improved data acquisition on macrozooplankton, including non-crustacean zooplankton, and other under-surveyed groups. Taxa of interest include e.g. cnidarians, ctenophores, tunicates, chaetognaths, gastropods, polychaetes, mysids, euphausiids, as well as various meroplanktonic larvae.

Preliminary contact points for ToR F:  Agata Weydmann-Zwolicka and Aino Hosia

ToR G:  Outreach, mentoring and training

Outreach activities in WGZE are extremely important to connect all researchers working on zooplankton in the ICES area, spreading knowledge and expertise within the group and transferring it to other scientists in the ICES community and to the public. This ambition is connected to the present ICES Science Plan as one of its outcomes is to have marine science with a high and beneficial impact on society. On the other hand, training is becoming more and more a necessity through the zooplankton science community, especially in terms of assessing biodiversity and integrative identification of plankton species that are key to many ecology studies. Finally, mentoring is regarded as a way to bring early career scientists to the group and ICES, in order to expand the current pool of experts. This ToR will also support the editors of the ID Leaflets for Plankton and the development of theme sessions for the ICES ASC within the WGZE community.

Preliminary contact points for ToR G:  Antonina dos Santos and Lidia Yebra