The Subantarctic Zone of the Southern Ocean plays a disproportionally large role on the Earth system. Model projections predict rapid environmental change in the coming decades, including ocean acidification, warming, and changes in nutrient supply which pose a serious risk for marine ecosystems. Yet despite the importance of the Subantarctic Zone, annual and inter-annual time series are extremely rare, leading to important un...

Coccolithophores are an important group of calcifying marine phytoplankton. Although coccolithophores are not silicified, some species exhibit a requirement for Si in the calcification process. These species also possess a novel protein (SITL) that resembles the SIT family of Si transporters found in diatoms. However, the nature of Si transport in coccolithophores is not yet known, making it difficult to determine the wider ro...

Coccolithophores are a calcifying unicellular phytoplankton group that are at the base of the marine food web, and their lipid content provides a source of energy to consumers. Coccolithophores are vulnerable to ocean acidification and warming, therefore it is critical to establish the effects of climate change on these significant marine primary producers, and determine potential consequences that these changes can have on th...

Haptophytes are photosynthetic protists found in both freshwater and marine environments with an origin possibly dating back to the Neoproterozoic era. The most recent molecular phylogeny reveals several haptophyte “mystery clades” that await morphological verification, but it is otherwise highly consistent with morphology-based phylogenies, including that of the coccolithophores (calcifying haptophytes). The fossil coccolith...

Ongoing ocean warming and acidification are tied to the rapid accumulation of human‐induced carbon dioxide (CO 2 ) in the atmosphere and subsequent uptake of heat and CO 2 by the surface ocean. These processes are expected to drive large changes in marine ecosystems. While numerous studies have examined the effects of ocean acidification on coccolithophores, less is known on their combined effect. In this study, we investigate...

In this laboratory study, we monitored the buildup of biomass and concomitant shift in seawater carbonate chemistry over the course of a Trichodesmium bloom under different phosphorus (P) availability. During exponential growth, dissolved inorganic carbon (DIC) decreased, while pH increased until maximum cell densities were reached. Once P became depleted, DIC decreased even further and total alkalinity (TA) dropped, accompani...

Various protective and metabolic functions for coccolithophore calcification have been proposed such as providing a means to supply CO 2 for photosynthesis. It has also been speculated that calcification helps to dissipate excess energy under high irradiance, thereby circumventing photoinhibition. To address these questions, cells of a calcifying strain of Emiliania huxleyi were grown at three irradiances (30, 300, and 800 µmo...