Coccolithophores are a diverse group of marine, unicellular organisms with the ability to produce intricately-formed exoskeletons of tiny calcium carbonate plates (liths) and thus are intimately linked to global carbon cycles in the ocean. The ability of coccolithophores to perform photosynthesis and calcification means they are central to marine carbonate cycles and can influence ocean-atmosphere CO2 exchange, and export organic and inorganic carbon to the deep ocean.
Whilst the cells are microscopic and require electron microscopy for detailed identification, large oceanic blooms can be seen from space. Coccospheres and liths are well preserved in water samples and deep-sea sediments and they are frequently used to assess biogeochemical processes in contemporary and past populations.
We describe the diversity of coccolithophorid species observed in the Sub-Antarctic Zone of the Southern Ocean, a region that plays a disproportionately large role in the uptake and storage of anthropogenic CO2. We highlight the use of multiple, long-term monitoring programs supported by IMOS to collect water and sediment trap samples, and deep sea-sediments to catalogue floristic diversity of coccolithophores in the region. These biodiversity records are important for assessing changes in community composition as a result of environmental change, namely warming and ocean acidification.