What factors control coccolithophore growth rates?
Lead Research Organisation:
NATIONAL OCEANOGRAPHY CENTRE
Department Name: Science and Technology
Abstract
Coccolithophores are a unique group of microscopic marine algae that produce small scales of CaCO3 (coccoliths), which form an outer shell (coccosphere) around the cell. Coccolithophores have important roles in the marine carbon cycle as they convert CO2 into both organic matter (via photosynthesis) and CaCO3 (via calcification), and coccoliths are effective agents at transferring CO2 as CaCO3 (calcite) from the surface to deep ocean. Coccoliths are also heavier than organic matter and add weight to sinking material so that it also reaches the deep sea. Although coccolithophores have a rich fossil record they face a bleak and uncertain future - increased atmospheric CO2 will cause ocean acidification and a chemical environment unfavourable to calcifying organisms, while global warming will change how the oceans are mixed and the availability of energy (sunlight) and nutrients (nitrogen, phosphorus) needed for growth. However, it is not fully understood how ocean chemistry or the availability of light and nutrients effects coccolithophore growth in the present-day ocean, and until this gap is addressed it is difficult to fully appreciate or predict how coccolithophores may react to climate change. Due to the inclusion of both calcite and organic matter within coccolithophore cells, both need to be considered when examining coccolithophore growth: understanding how coccolithophores balance cellular levels and rates of production of these two materials is key to understanding their growth and role in the marine carbon cycle. The aim of this project is to address these deficiencies by studying both natural coccolithophore communities in the ocean and individual species grown in the laboratory. In order to examine cellular levels of calcite and organic matter, photosynthesis and calcification, and growth rates it will be necessary to look closely at the structure of the coccosphere, coccolith and inner organic cell. The combination of knowledge from oceanic coccolithophore communities and those grown under more controlled conditions in the laboratory will create an overview of the principals governing coccolithophore growth. The end goal of this project will be to use this overview to generate a mathematical model that describes coccolithophore growth in relation to the coccosphere/cell structure and the availability of light and nutrients. Such a model can then be used to address global questions about coccolithophore ecology, their role in the marine carbon cycle and their future in a changing climate.
Publications
Balch W
(2014)
Surface biological, chemical, and optical properties of the Patagonian Shelf coccolithophore bloom, the brightest waters of the Great Calcite Belt
in Limnology and Oceanography
Balch W
(2011)
Zonal and meridional patterns of phytoplankton biomass and carbon fixation in the Equatorial Pacific Ocean, between 110°W and 140°W
in Deep Sea Research Part II: Topical Studies in Oceanography
Brzezinski M
(2011)
Co-limitation of diatoms by iron and silicic acid in the equatorial Pacific
in Deep Sea Research Part II: Topical Studies in Oceanography
Charalampopoulou A
(2016)
Environmental drivers of coccolithophore abundance and calcification across Drake Passage (Southern Ocean)
in Biogeosciences
Charalampopoulou A
(2011)
Irradiance and pH affect coccolithophore community composition on a transect between the North Sea and the Arctic Ocean
in Marine Ecology Progress Series
Daniels C
(2016)
Species-specific calcite production reveals Coccolithus pelagicus as the key calcifier in the Arctic Ocean
in Marine Ecology Progress Series
Daniels C
(2011)
The influence of lithogenic material on particulate inorganic carbon measurements of coccolithophores in the Bay of Biscay
in Limnology and Oceanography
De Vries J
(2021)
Haplo-diplontic life cycle expands coccolithophore niche
in Biogeosciences
De Vries J
(2020)
The haplo-diplontic life cycle expands niche space of coccolithophores
Monteiro FM
(2016)
Why marine phytoplankton calcify.
in Science advances
Poulton A
(2011)
Biometry of detached Emiliania huxleyi coccoliths along the Patagonian Shelf
in Marine Ecology Progress Series
Poulton A
(2014)
Coccolithophores on the north-west European shelf: calcification rates and environmental controls
in Biogeosciences
Poulton A
(2013)
The 2008 Emiliania huxleyi bloom along the Patagonian Shelf: Ecology, biogeochemistry, and cellular calcification
in Global Biogeochemical Cycles
Poulton A
(2017)
Coccolithophore ecology in the tropical and subtropical Atlantic Ocean: New perspectives from the Atlantic meridional transect (AMT) programme
in Progress in Oceanography
Sanders R
(2014)
The Biological Carbon Pump in the North Atlantic
in Progress in Oceanography
Smith H
(2017)
The influence of environmental variability on the biogeography of coccolithophores and diatoms in the Great Calcite Belt
in Biogeosciences
Villiot N
(2021)
Allometry of carbon and nitrogen content and growth rate in a diverse range of coccolithophores.
in Journal of plankton research