Determinants of Planktonic Foraminifera Calcite Flux: Implications for the Prediction of Intra‐ and Inter‐Annual Pelagic Carbonate Budgets

Abstract

Pelagic carbonate production is an important element of the global carbon cycle. Through biomineralization of either calcite or aragonite, marine plankton binds large amounts of dissolved inorganic carbon in their shells, which are then exported from the productive zone (Milliman, 1993). A large part of the aragonite flux, which consists exclusively of pteropods (Buitenhuis et al., 2019;Fabry, 1989;Singh & Conan, 2008), is dissolved before being buried in the sediment (Berner & Honjo, 1981). However, calcite (especially low-magnesium calcite in planktonic foraminifera shells) is less prone to dissolution (Keir, 1980), making the burial of biogenic calcite the main mechanism to transfer carbon from the rapidly cycling ocean-atmosphere-biosphere to the slow geological reservoir (Archer, 1996;Catubig et al., 1998). In addition, biogenic carbonate production has an opposing fast effect on the carbon cycle, as well as the marine biological carbon pump. By consuming alkalinity, it induces degassing of carbon dioxide and thus acts as a "counter pump" in the process of biological carbon sequestration in the ocean (Frankignoulle & Canon, 1994). Planktonic foraminifera shells are a key component of marine biogenic calcite production and flux. Upon death of these organisms, their shells begin to settle through the water column, and the resulting export flux is estimated to constitute up to half of the global calcite flux (Schiebel, 2002;Schiebel et al., 2007). The rest of the pelagic calcite flux is dominated by coccoliths (Baumann et al., 2004;Milliman, 1993). However, in order to quantify the pelagic calcite budget, planktonic foraminifera cannot be ignored. The planktonic foraminifera shell flux is a variable in both space and time (Jonkers & Kucera, 2015;Žarić et al., 2005), yet the factors controlling the shell flux variability are not completely constrained and understood. Furthermore, the subject concerning how shell flux variability relates to mass flux variability has not been explicitly studied before. In theory, variability in the planktonic foraminifera calcite flux could arise from changes in the shell flux and thus reflect population growth and/or changes in the shell mass, which consequently reflect individual

Quantitative and mechanistic understanding of the open ocean carbonate pump - perspectives for remote sensing and autonomous in situ observation

“…Other region-specific studies show highly variable results on the contribution of foraminifera to PIC flux, such as 10-40% in the North Atlantic (Salmon et al, 2015), 15% for the Indian Ocean (Rembauville et al, 2016), 22% for the Sargasso Sea (Deuser and Ross, 1989), and 30% in the south-west Pacific . Global estimates generally fall between 3 and 30% (Buitenhuis et al, 2019;Kiss et al, 2021), but substantially higher contributions (56-88%) have also been estimated (Honjo et al, 2008;Schiebel, 2002).…”

Calcification response of planktic foraminifera to environmental change in the Western Mediterranean Sea during the industrial era

“…On an interannual time scale, different studies Osborne et al, 2016) have shown that sea surface warming and carbonate system parameters are the most likely parameters to control calcification on key calcifying phytoplankton species such as the coccolithophore Emiliania huxleyi organisms (Meier et al, 2014). However, datasets from sediment traps that cover a wide span of years and in which foraminifera weights have been analyzed are rare (Kiss et al, 2021), therefore it is difficult to place our results in a more global context. Our analysis suggests that the trends observed in the carbonate system (Figure 5 This pH decrease, combined with the carbonate system parameters seem to affect G. bulloides and N. incompta calcification patterns in recent years, however, the degree to which each species react to a change in these parameters differs.…”

Daily timescale dynamics of planktonic foraminifera shell-size distributions

“…To compare PF shell-size globally, the shell-size of six abundant species in the GOA (G. ruber, G. glutinata, G. rubescens + G. tenellus, G. calida, G. siphonifera and O. universa) were compared to corresponding shells collected from surface sediment samples in subtropical and tropical regions (Rillo et al, 2020) and sediment trap samples from an upwelling area (Cape Blanc, Kiss et al, 2021). For consistency, only PF shell-sizes larger than 150 µm from the GOA were considered for this comparison (Table S2, third column).…”