Morphology of <i>Emiliania huxleyi</i> coccoliths on the North West European shelf – is there an influence of carbonate chemistry?

Abstract

Abstract. Within the context of the UK Ocean Acidification project, Emiliania huxleyi (type A) coccolith morphology was examined from samples collected during cruise D366. In particular, a morphometric study of coccolith size and degree of calcification was made on scanning electron microscope images of samples from shipboard CO2 perturbation experiments and from a set of environmental samples with significant variation in calcite saturation state (Ωcalcite). One bioassay in particular (E4 from the southern North Sea) yielded unambiguous results – in this bioassay exponential growth from a low level occurred with no artificial stimulation and coccosphere numbers increased ten-fold during the experiment. The samples with elevated CO2 saw significantly reduced coccolithophore growth. However, coccolithophore morphology was not significantly affected by the changing CO2 conditions even under the highest levels of perturbation (1000 μatm). Environmental samples similarly showed no correlation of coccolithophore morphology with calcite saturation state. Some variation in coccolith size and degree of calcification does occur but this seems to be predominantly due to genotypic differentiation between populations on the shelf and in the open ocean.

Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore <i>Emiliania huxleyi</i>

“…In addition, the present study is only based on a single strain of Southern Hemisphere E. huxleyi. Due to the wide distribution of this species in the natural marine environment, E. huxleyi presents high variability in terms of genetic, morphological, and physiological characteristics (Cook et al, 2011;Read et al, 2013;Young et al, 2014). Therefore, the physiology of different E. huxleyi strains isolated from different geographic locations might respond differently to changing environmental drivers.…”

Influence of ocean acidification on the complexation of iron and copper by organic ligands in estuarine waters

“…The projected changes in the marine carbonate system will likely have profound biological consequences for oceanic and near-coastal ecosystems within the coming Marine Chemistry xxx (2015) xxx-xxx decades and centuries (Guinotte and Fabry, 2008) with anticipated detrimental effects on marine calcifiers (Fabry, 2008), corals (Hoegh-Guldberg et al, 2007), mollusks (Gazeau et al, 2013) and crustaceans (Whiteley, 2011), making it more difficult to build and maintain skeletons, tests, and shells of calcium carbonate (Doney, 2006). The effects of ocean acidification on coccolithophore calcification are not fully resolved and a topic of much debate (Iglesias-Rodriguez et al, 2008;Riebesell et al, 2000;Young et al, 2014) with reported species specific responses to ocean acidification (Langer et al, 2006). Furthermore, our understanding on the effects of ocean acidification on non-calcifying marine organisms, ecosystem diversity and biogeochemical processes is only just emerging (Gattuso et al, 2013;MacGilchrist et al, 2014;Raven et al, 2005;Richier et al, 2014).…”

An updated synthesis of the observed and projected impacts of climate change on the chemical, physical and biological processes in the oceans

“…There is medium evidence and low agreement on how coccolithophore growth and calcification will be affected as they exhibit highly varied responses depending on species, strain and secondary environmental controls such as irradiance, bloom species composition and nutrient availability (Benner et al, 2013;Horigome et al, 2014;Muller and Nisbet, 2014;Poulton et al, 2014;Sett et al, 2014;Young et al, 2014). There is evidence that the coccolithophore, Emiliania huxleyi, has the capacity to evolve genetic adaptions to both warming and ocean acidification expected under RCP8.5 (Benner et al, 2013;Lohbeck et al, 2014;Schluter et al, 2014).…”