Sensitivity of Calcification to Thermal Stress Varies among Genera of Massive Reef-Building Corals

Abstract

Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously affecting ecosystem function in Atlantic reefs.

Is there a role of coral bone substitutes in bone repair?

“…Furthermore, some authors highlighted the negative effect or even complete cessation of the overall calcification that the rising water temperature and acidity has on these corals. 13,93,94 In addition, a substantial decrease in the coral reefs has been noted since 1990 and it is expected that approximately 50% of the reefs will be destroyed by 2030. 13 These data add to the overall uncertainty when planning to explore the utilization of the corals further.…”

Low Florida coral calcification rates in the Plio-Pleistocene

“…Thus, acclimatisation effects on calcification seem to play a role within rather small observational scales. Within the same region, another species of the same genus (Orbicella falveolata), however, responds with declining calcification to this subtle gradient of ∼ 1 • C of average annual SST change (Carricart-Ganivet et al, 2012), either because acclimatisation is not yet fully accomplished, or because the SST regime is near the upper threshold of ecological tolerance of O. falveolata allowing no further positive acclimatisation. We assume, the latter is more likely and, therefore, calcification responses to SST seem to be non-linear over the full range of ecological tolerance of this and other taxa.…”

“…For an understanding of the possible mechanisms behind these low calcification rates, we use modern analogue data compiled from the literature on recent z corals of the WA and Indo-Pacific (IP). According to this database, temperature generally boosts calcification rates in modern z corals, but field studies on single species of z coral suggest the rates to decline beyond optimum values (Carricart-Ganivet et al, 2012;Cooper et al, 2008). The nonlinearity of calcification rates (g cm −2 yr −1 ) derives from inputs of two independent variables: skeletal growth rate (extension rate, cm yr −1 ) and skeletal density (g cm −3 ; Lough, 2008).…”

“…The nonlinearity of calcification rates (g cm −2 yr −1 ) derives from inputs of two independent variables: skeletal growth rate (extension rate, cm yr −1 ) and skeletal density (g cm −3 ; Lough, 2008). The temperature effects on extension rates of Porites from the IP are well documented over a large temperature window and display slow increases with temperature below but sharp decreases above optimum (Cantin et al, 2010;Carricart-Ganivet et al, 2012;Lough and Barnes, 2000). The temperature responses of extension rate and density, however, are generally believed to markedly differ according to taxon and/or ocean region (Highsmith, 1979) and are further complicated by proximality trends reflecting temperature and seasonality gradients, exposure, effluxes of "inimical" bank waters, or nutrient supplies (Lough and Cooper, 2011;Manzello et al, 2015b).…”

Estimation of uncertainty for massive Porites coral skeletal density

“…Bessat and Buigues, 2001) or suggesting the high/low-density band forms in same season for all analysis coral (e.g. Carricart-Ganivet et al, 2012, Carilli et al, 2012Cooper et al, 2012;Helmle et al, 2011;Castillo et al, 2011;Cantin et al, 2010;De'ath et al, 2009;Cooper et al, 2008). As geochemical signals ( 18 O, Sr/Ca ratio) can support chronologies through quantitative verification, coral growth parameters should be the primary data set.…”