Working Group on Phytoplankton and Microbial Ecology (WGPME; Outputs from 2024 Meeting)

The ICES Working Group on Phytoplankton and Microbial Ecology (WGPME) provides tools and expert perspectives on ecology, taxonomy, and methodological analysis of phytoplankton and other planktonic microbes that contribute to ecosystem services such as oxygen production and nutrient cycling. The working group has 45 members as of 2024, seven of which are new to WGPME with attendees. The groups ToRs reflect the needs of the scientific community related to marine management: access to data and easily accessible figures from long-term datasets and to develop ecological interpretations of changing phytoplankton seascape. The group produced 93 publications between 2021–2024 including key tools, a Metabase report and online data visualization tool on long-term phytoplankton trends and cross-disciplinary outputs.

Long-term ecology: The cooperative zooplankton and phytoplankton report (ToR D) has compiled data from all ICES coastal and open water ecoregions and additional Western Atlantic stations and near completion by January 2025. Major phytoplankton shifts are observed. ToR C long-term phytoplankton influences aim to generate a manuscript on cyanobacterial trends from multiple stations because models and hindcast publications predict an increasing dominance of smaller phytoplankton in several North Atlantic regions. This will influence marine foodwebs.

Tools: ToR E Metazoogene DNA-based species mapping tool has added more than 84 000 phytoplankton and microbe species (https://metazoogene.org/atlas) with increasing trends in using genetic analysis alongside microscopy, this will allow non experts to visualize genetically identified species alongside other datasets. Metazoogene is a cooperative effort with WGIMT and WGZE. This challenging task will mean this ToR will continue to curate and improve visualization tools. ToR F aims to report on rare taxa that are non-native or rarely recurring with 18 new observations. New phytoplankton, including harmful algae, have been reported and new mapping tools have been developed and visualized from OBIS to assess spatio-temporal trends from the origin of first sighting.

Information and management: In ToR A, we are gathering information on nano and picoplankton (small phytoplankton less than 10 and 2μm respectively) to incorporate into global datasets. Data from 17 stations from nine countries will be incorporated into Metabase database with increasing monitoring and regulation of smaller phytoplankton. ToR B has assisted members in methods or tools for members to developing indicators for their region or country. This term members delivered nine phytoplankton and ecosystem assessment reports at national and regional levels for OSPAR and HELCOM and seven publications WGPME developing indicators, with increasing use of high-throughput observations.

Collaboration and communication: WGPME chair R. Stern co convened thematic session F at ICES ASC 2023 with WGHABD (D. Clarke) and WGIMO (C. McKenzie) with 134 hybrid attendees and 26 presentations where we delivered recommendations for integrating genetics into marine management. In 2024, we have been introduced to IOC group TrendsPO with members collaborating on similar objectives.