Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

Abstract

has not yet been a comprehensive analysis that considers both experimental datasets and explores the implications for interpreting coral skeletons. Here, we evaluate four potential K D formulations: three previously presented in the literature and one newly developed. We assess how well each formulation reconstructs the known fluid carbonate chemistry from the abiogenic experiments, and we evaluate the implications for deriving the carbonate chemistry of coral calcifying fluid. Three of the K D formulations performed similarly when applied to abiogenic aragonites precipitated from 10 seawater and to coral skeletons. Critically, we find that some uncertainty remains in understanding the mechanism of boron elemental partitioning between aragonite and seawater, and addressing this question should be a target of additional abiogenic precipitation experiments. Despite this, boron systematics can already be applied to quantify the coral calcifying fluid carbonate system, although uncertainties associated with the proxy system should be carefully considered for each application. Finally, we present a user-friendly computer code that calculates coral calcifying fluid carbonate chemistry, including propagation of 15 uncertainties, given inputs of boron systematics measured in coral skeleton.

Environmental and physiochemical controls on coral calcification along a latitudinal temperature gradient in Western Australia

“…To estimate [] cf , we assume that the concentration of total inorganic boron in the calcifying fluid is only salinity dependent (Foster, Pogge von Strandmann, & Rae, ) and equal to that of the surrounding seawater (Lee et al, ). A strong linear relationship ( r 2 = 0.93) exists between the derived [] cf (using Equation ) and the known [] cf from abiotic experiments by Holcomb et al, () (see DeCarlo, Holcomb, & McCulloch, ; Ross et al, ).…”

“…The concentration of DIC cf was then estimated from pH cf and [] cf (D'Olivo & McCulloch, ; McCulloch et al, ) using the CO2SYS program (Lewis et al, ). The systematic error in estimating [] cf and DIC cf (using the JCp‐1 standard as an example) corresponds to 49 and 149 µmol/kg, respectively (DeCarlo, Holcomb, et al, ).…”

Porites Calcifying Fluid pH on Seasonal to Diurnal Scales

“…However, while we have followed the DeCarlo et al. (2018) approach in converting B/Ca to, it should also be noted that others have suggested there is a temperature dependency of boron incorporation into aragonite (Cai et al., 2016; Chen et al., 2015). This may be complicating the estimates of calcifying fluid carbonate system parameters we make here from B/Ca.…”

“…Calculation of carbonate parameters from B/Ca followed DeCarlo et al. (2018) using the partition coefficient from McCulloch et al. (2018).…”

Investigating marine bio‐calcification mechanisms in a changing ocean with in vivo and high‐resolution ex vivo Raman spectroscopy

“…This advance can help to resolve the problem of differing temporal and spatial scales among techniques used in coral calcification studies (Holcomb et al, ). Although geochemical (i.e., isotopic and elemental) analyses of coral skeletons are effective at deriving the carbonate system of the calcifying fluid (DeCarlo, Holcomb, & McCulloch, ; McCulloch, D'Olivo Cordero, Falter, Holcomb, & Trotter, ), such studies have been difficult to reconcile with alternative approaches based on inserting micro‐sensors into the coral calcifying fluid (Al‐Horani, Al‐Moghrabi, & De Beer, ; Cai et al, ; Ries, ; Sevilgen et al, ), or imaging the calcifying fluid of corals exposed to pH‐sensitive dyes (Comeau et al, ; Holcomb et al, ; Venn, Tambutte, Holcomb, Allemand, & Tambutte, ). Conversely, Raman spectroscopy can now be applied in vivo at temporal and spatial scales comparable to the micro‐sensor studies (Figure ), as well as to bulk powders for comparison to isotopic measurements (e.g., DeCarlo et al, , DeCarlo, Comeau et al, ).…”