Deconstructing the response of plankton lifeform indicators to climate change

Plankton are sensitive to hydro-climatic variability, and plankton community structure and composition has been documented to ‘shift and shuffle’ in response to climate change. Indicators that summarise these community changes are required to monitor ecosystem changes for marine management. One approach to indicator development is to group plankton taxa into broad-scale taxonomic functional groups, termed ‘lifeforms’. Taxa within these functional groups share traits that govern their ecological role, such as their efficiency in transferring energy to higher trophic levels. It could be assumed that these same traits also govern the responses of taxa to changes in their environment, so that taxa within functional groups share responses to environmental change, but it is as yet undetermined the extent to which this assumption holds true. Here, we used a species archetype modelling approach on a multidecadal plankton dataset to cluster plankton taxa by their response to sea surface temperature change. We then examined the distribution of these responses within functional groups. We find that for phytoplankton, whether individual taxa are dinoflagellates was a factor determining their response to SST. In contrast, none of the zooplankton groups showed a tendency towards a particular response, suggesting that factors other than lifeform group membership, such as biogeographic affinity, are more important in determining responses to SST change. These results have implications for both our understanding of plankton community responses to climate change, and in the formal assessment and monitoring of these changes under management frameworks.

Download poster: Deconstructing the response of plankton lifeform indicators to climate change