The ocean biosphere in the Earth System - Katherine Richardson Group

Research in this group focuses on understanding the factors controlling the structure of marine plankton ecosystems, community composition, how genetic diversity is maintained and what role life histories of organisms and ecosystem structure play in the global carbon cycle and climate development

Ocean

Research focus

Exploring the role of sub-mesoscale oceanographic features in establishing pelagic habitats for phytoplankton. It has long been believe that, because water in the ocean ultimately mixes, that phytoplankton should show minimal genetic diversity. Indeed the classic “paradox of the plankton” (Hutchinson 1961) asks how there can be so many species in what appears (to us!) as a homogeneous habitat. This research employs eDNA to identify unique communities and relate these to varying environmental conditions, including turbulence, in order to understand how small-scale differences in the environment influence plankton diversity.
Relating plankton ecosystem structure to carbon flows. On land ~450 Gt C is bound up in vegetation (which can be regarded as a carbon stock). Although photosynthesis (carbon flow into the stock) of the same order of magnitude in the ocean than on land, the biomass of the vegetation is <1% of that on land. In order for photosynthesis in the ocean to lead to C sequestration, the fixed carbon must be transported to below the permanent thermocline. The biodiversity of the phytoplankton and the structure of the planktonic ecosystem are both critical factors in determining how much of the carbon fixed through photosynthesis reaches the interior of the ocean and is sequestered. The aim of this research in this theme is to unravel the relationships between plankton biodiversity/ecosystem structure and ocean-atmosphere carbon fluxes. This theme houses the Queen Margrethe and Vigdís Finnbogadóttir Interdisciplinary Research Centre on Ocean, Climate, and Society (ROCS) where, in cooperation with the Section on GeoGenetics, ocean sediment cores are being analysed for DNA in order to describe plankton ecosystem structure in relation to climate change in the prehistoric ocean.
Planetary Boundaries: As far as we know, Earth is the only planet with life. Life is fuelled by the transport and transformation of elements and is, therefore, a critical determinant in establishing global cycles of elements, including C. The Earth behaves as a complex system and, it is the interaction between life and geo-physical processes that establishes the state of the Earth System, i.e., the conditions, including climate, experienced. Research is carried out attempting to quantify how changes in biological processes may influence the future trajectory of the Earth System.

Key publications

Steffen, W., Richardson, K., Rockström, J., Schellnhuber, J.H., Dube, P.O., Dutreuil, S., Lenton, M.T. & Lubchenco, J. 2020. The emergence and evolution of Earth System Science. Nature Reviews. Earth & Environment. Volume: 1. DOI: 10.1038/s43017-019-0005-6
Lade, J.S., Steffen, W., de Vries, W., Carpenter, R.S., Donges, F.J., Gerten, D., Hoff, H., Newbold, T., Richardson, K. & Rockström, J. 2019. Human impacts on planetary boundaries amplified Earth System interactions. Nature Sustainability. Volume: DOI: 10.1038/s41893-019-0454-4
Steffen, W., Rockstrom, J. & Richardson, K., et al. 2018. Trajectories of the Earth System in the Anthropocene. Proceedings of the National Academy of Sciences of the United States of America 115 (33): 8252-8259 DOI: 1073/pnas.1810141115.

See full list of publications by Katherine Richardson