Meta‐analysis reveals negative yet variable effects of ocean acidification on marine organisms

Abstract

Ocean acidification is a pervasive stressor that could affect many marine organisms and cause profound ecological shifts. A variety of biological responses to ocean acidification have been measured across a range of taxa, but this information exists as case studies and has not been synthesized into meaningful comparisons amongst response variables and functional groups. We used meta-analytic techniques to explore the biological responses to ocean acidification, and found negative effects on survival, calcification, growth and reproduction. However, there was significant variation in the sensitivity of marine organisms. Calcifying organisms generally exhibited larger negative responses than noncalcifying organisms across numerous response variables, with the exception of crustaceans, which calcify but were not negatively affected. Calcification responses varied significantly amongst organisms using different mineral forms of calcium carbonate. Organisms using one of the more soluble forms of calcium carbonate (high-magnesium calcite) can be more resilient to ocean acidification than less soluble forms (calcite and aragonite). Additionally, there was variation in the sensitivities of different developmental stages, but this variation was dependent on the taxonomic group. Our analyses suggest that the biological effects of ocean acidification are generally large and negative, but the variation in sensitivity amongst organisms has important implications for ecosystem responses.

Regulation of gene expression is associated with tolerance of the Arctic copepod Calanus glacialis to CO2‐acidified sea water

“…By measuring the response to low pH at multiple levels of biological organization, both organismal and molecular, we detected physiological changes in response to low pH that were undetected in organismal measures. Additionally, there continues to be considerable inconsistency in the measured responses of marine organisms to low pH, even within taxa (Kroeker et al., 2010; Kroeker, Kordas, & Crim, 2013). Therefore, these results on the molecular response of an apparently tolerant species will improve our understanding of the physiological basis of low pH tolerance that is found in some, but not all species.…”

Species-specific responses to ocean acidification should account for local adaptation and adaptive plasticity

“…To evaluate the mean effect of high p CO2 conditions on different physiological traits among taxa, we estimated the ln-transformed response ratio 11 …”

“…Scientists have now conducted many different ocean acidification experiments on a variety of marine species, usually exposing these organisms over short-or mid-term periods to experimental conditions based on scenarios modelled for oceanic waters 9 , typically simulating present (for example, ~400 μ atm) and near-future ocean p CO2 levels (for example, 650, 750 and/or 1,000 μ atm) 10 . Through this experimental approach, a variety of different biological responses have been studied, including photosynthesis, growth, ingestion, calcification, reproduction, behaviour, gene expression and biological interactions, among others 11 .…”

How will Ocean Acidification Affect Baltic Sea Ecosystems? An Assessment of Plausible Impacts on Key Functional Groups

“…More detailed meta-analyses of published results have drawn divergent conclusions, although some prominent examples have been based on flawed methodologies. A recent comprehensive meta-analysis (Kroeker et al 2010) concluded that overall effects on marine animals are negative, while effects on marine primary producers are generally positive. The overriding result from this analysis, however, was that substantial variation exists among the responses of different taxa and processes to acidification (e.g.…”