• Energy Research

Data and scripts used for the paper 'A global census of the significance of giant mesopelagic protists to the biogeochemical cycles of carbon and silicon' authored by: Manon Laget, Laetitia Drago, Thelma Panaïotis, Rainer Kiko, Lars Stemmann, Andreas Rogge, Natalia Llopis-Monferrer, Aude Leynaert, Jean-Olivier Irisson, Tristan Biard

Data and scripts used for the paper 'A global census of the significance of giant mesopelagic protists to the biogeochemical cycles of carbon and silicon' authored by: Manon Laget, Laetitia Drago, Thelma Panaïotis, Rainer Kiko, Lars Stemmann, Andreas Rogge, Natalia Llopis-Monferrer, Aude Leynaert, Jean-Olivier Irisson, Tristan Biard

AbstractZooplankton are major consumers of phytoplankton primary production in marine ecosystems. As such, they represent a critical link for energy and matter transfer between phytoplankton and bacterioplankton to higher trophic levels and play an important role in global biogeochemical cycles. In this Review, we discuss key responses of zooplankton to ocean warming, including shifts in phenology, range, and body size, and assess the implications to the biological carbon pump and interactions with higher trophic levels. Our synthesis highlights key knowledge gaps and geographic gaps in monitoring coverage that need to be urgently addressed. We also discuss an integrated sampling approach that combines traditional and novel techniques to improve zooplankton observation for the benefit of monitoring zooplankton populations and modelling future scenarios under global changes.

Microbial communities have essential roles in ocean ecology and planetary health. Microbes participate in nutrient cycles, remove huge quantities of carbon dioxide from the air and support ocean food webs. The taxonomic and functional diversity of the global ocean microbiome has been revealed by technological advances in sampling, DNA sequencing and bioinformatics. A better understanding of the ocean microbiome could underpin strategies to address environmental and societal challenges, including achievement of multiple Sustainable Development Goals way beyond SDG 14 'life below water'. We propose a set of priorities for understanding and protecting the ocean microbiome, which include delineating interactions between microbiota, sustainably applying resources from oceanic microorganisms and creating policy- and funder-friendly ocean education resources, and discuss how to achieve these ambitious goals.

Planktonic organisms play crucial roles in oceanic food webs and global biogeochemical cycles. Most of our knowledge about the ecological impact of large zooplankton stems from research on abundant and robust crustaceans, and in particular copepods. A number of the other organisms that comprise planktonic communities are fragile, and therefore hard to sample and quantify, meaning that their abundances and effects on oceanic ecosystems are poorly understood. Here, using data from a worldwide in situ imaging survey of plankton larger than 600 μm, we show that a substantial part of the biomass of this size fraction consists of giant protists belonging to the Rhizaria, a super-group of mostly fragile unicellular marine organisms that includes the taxa Phaeodaria and Radiolaria (for example, orders Collodaria and Acantharia). Globally, we estimate that rhizarians in the top 200 m of world oceans represent a standing stock of 0.089 Pg carbon, equivalent to 5.2% of the total oceanic biota carbon reservoir. In the vast oligotrophic intertropical open oceans, rhizarian biomass is estimated to be equivalent to that of all other mesozooplankton (plankton in the size range 0.2-20 mm). The photosymbiotic association of many rhizarians with microalgae may be an important factor in explaining their distribution. The previously overlooked importance of these giant protists across the widest ecosystem on the planet changes our understanding of marine planktonic ecosystems.

Abstract Current climate change is significantly modifying Arctic ecosystems and their components, but the reference and direction of these changes are still undefined. The aim of this study was to provide well-grounded data on the present composition and structure of zooplankton from boreal to Arctic latitudes. This comparative study was performed with a unified methodology in six fjords located along the west coasts of Norway and Svalbard. Comparisons between the fjords' environmental characteristics (temperature, salinity, chlorophyll, and particles) and the zooplankton community, described with several metrics (abundance and biovolume) and traits (taxonomy and size), were performed to recognise the potential of various ecological indicators for future monitoring. While hydrography and the taxonomic composition of zooplankton were specific to each fjord and changed along the latitudinal environmental gradient, the clustering of particle characteristics (size, concentration, and transparency) and zooplankton size structures alludes to their susceptibility to additional, local processes. The differences in the biotic and abiotic characteristics distinguished the semi-closed fjords from the fjords prone to Atlantic water advection. The fjords with a limited water mass exchange incorporated local or Arctic-type waters and were host to specific zooplankton communities and particles, with the marked presence of species adapted to high particle concentrations (Microsetella norvegica) or species of Arctic affiliation (Calanus glacialis). In the open fjords, zooplankton communities were characterised by the predomination of Oithona similis and Calanus finmarchicus, confirming influence of Atlantic water. The zooplankton community size structure, expressed as abundance, was mainly shaped by changes in the contributions of small copepods, whereas the size structure expressed as biovolume reflected the differences in the co-occurring sibling species of Calanus spp. and/or differences in their dominating life stages. The results of this integrative across-system study constitute a necessary baseline for the future monitoring of changes in the zooplankton communities, which are likely to occur in response to climate change at high latitudes.