Calcifying Species Sensitivity Distributions for Ocean Acidification

Abstract

Increasing CO2 atmospheric levels lead to increasing ocean acidification, thereby enhancing calcium carbonate dissolution of calcifying species. We gathered peer-reviewed experimental data on the effects of acidified seawater on calcifying species growth, reproduction, and survival. The data were used to derive species-specific median effective concentrations, i.e., pH50, and pH10, via logistic regression. Subsequently, we developed species sensitivity distributions (SSDs) to assess the potentially affected fraction (PAF) of species exposed to pH declines. Effects on species growth were observed at higher pH than those on species reproduction (mean pH10 was 7.73 vs 7.63 and mean pH50 was 7.28 vs 7.11 for the two life processes, respectively) and the variability in the sensitivity of species increased with increasing number of species available for the PAF (pH10 standard deviation was 0.20, 0.21, and 0.33 for survival, reproduction, and growth, respectively). The SSDs were then applied to two climate change scenarios to estimate the increase in PAF (ΔPAF) by future ocean acidification. In a high CO2 emission scenario, ΔPAF was 3 to 10% (for pH50) and 21 to 32% (for pH10). In a low emission scenario, ΔPAF was 1 to 4% (for pH50) and 7 to 12% (for pH10). Our SSDs developed for the effect of decreasing ocean pH on calcifying marine species assemblages can also be used for comparison with other environmental stressors.

The most primitive metazoan animals, the placozoans, show high sensitivity to increasing ocean temperatures and acidities

“…These observations not only highlight the sensitivity of placozoans to water acidity but also point to the potential of combining different sympatric placozoan species into a multiplespecies biomarker system. Several other examples of sympatric species complexes might be available also from different other invertebrate taxa (e.g., Azevedo et al, 2015;Hoegh-Guldberg & Bruno, 2010;Kroeker et al, 2013;Nakamura et al, 2011;Navarro et al, 2013;O'Donnell, Hammond, & Hofmann, 2009;Schmidt, Power, & Quinn, 2013).…”

Characterization model to assess ocean acidification within life cycle assessment

“…However, at the current state of knowledge, only few publications on this topic are available (e.g., Azevedo et al 2015). It is, therefore, of vital importance to strengthen the science basis of the cause-effect chain for ocean acidification in order to introduce endpoint characterization models in the future.…”

BGC-val: a model- and grid-independent Python toolkit to evaluate marine biogeochemical models

“…Similarly, the connections between different components of the Earth system can also be difficult to measure. Several crucial global fluxes are unknown or estimated with significant uncertainties, such as the global total flux of CO 2 into the ocean (Takahashi et al, 2009), the global total deposition of atmospheric dust (Mahowald et al, 2005), or the global production export flux (Boyd and Trull, 2007;Henson et al, 2011). Prior to the development of BGC-val, there was no evaluation toolkit specific to models of the marine ecosystem and evaluation was typically performed in an ad hoc manner.…”