The Combined Effects of Ocean Acidification and Heavy Metals on Marine Organisms: A Meta-Analysis

Abstract

Ocean acidification (OA) may interact with anthropogenic pollutants, such as heavy metals (HM), to represent a threat to marine organisms and ecosystems. Here, we perform a quantitative meta-analysis to examine the combined effects of OA and heavy metals on marine organisms. The results reveal predominantly additive interactions (67%), with a considerable proportion of synergistic interactions (25%) and a few antagonistic interactions (8%). The overall adverse effects of heavy metals on marine organisms were alleviated by OA, leading to a neutral impact of heavy metals in combination with OA. However, different taxonomic groups showed large variabilities in their responses, with microalgae being the most sensitive when exposed to heavy metals and OA, and having the highest proportion of antagonistic interactions. Furthermore, the variations in interaction type frequencies are related to climate regions and heavy metal properties, with antagonistic interactions accounting for the highest proportion in temperate regions (28%) and when exposed to Zn (52%). Our study provides a comprehensive insight into the interactive effects of OA and HM on marine organisms, and highlights the importance of further investigating the responses of different marine taxonomic groups from various geographic locations to the combined stress of OA and HM.

Emergent interactive effects of climate change and contaminants in coastal and ocean ecosystems

“…It will be necessary to increase our knowledge from laboratory, ecosystem-based field and process studies, as well as modelling, to have an overarching international action to facilitate and foster broad bidirectional science-policy interactions. The synergistic effects of various CC drivers are still mostly unexplored and demand urgent research studies (Cabral et al, 2019;Arrigo et al, 2020;Jin et al, 2021;Kibria et al, 2021).…”

“…Climate change drivers and pressures, specifically warming, stratification, acidification, deoxygenation, sea-level rise, extreme events (Figure 1) display interlinkages that lead to cumulative, antagonistic and synergic interactions, which can then alter the environmental fate, transport, chemical and physical speciation, availability, toxicity of contaminant, and pathways in marine food webs (Borga et al, 2012;Avendaño et al, 2016;Kibria et al, 2021). The interaction types differ among organisms from different climatic regions, and their variability is also dependent on the type and concentration of the contaminant (Jin et al, 2021). The interactions between CC and contaminants can exacerbate global pollution and must be considered in an integrated manner to properly assess the risk and vulnerability of ecosystem structure and functions, and also human well-being.…”

Influence of multiple global change drivers on plant invasion: Additive effects are uncommon

“…On the contrary, it is an antagonistic effect where the combined effect produces a more negative response than what it should be given an additive effect (Figure 1 of Crain et al 2008 ). In a series of articles, Piggott et al (2015a ; 2015b ; 2015c) proposed a classification system based on the additive effect model, which further refined the classification of interactions, and a new class of “mitigating synergism” is identified to accumulate the magnitude of the effect is measured compared with the individual stress effect to clarify the interaction effect of two factors with opposite effects ( Figure 1A ), and has been used by some authors recently ( Hale et al., 2017 ; Cremona et al., 2021 ; Jin et al., 2021 ).…”

Ocean Acidification-Mediated Food Chain Transfer of Polonium between Primary Producers and Consumers

“…There has been a growing interest in understanding the effect of ocean acidification (OA) in modulating the metal uptake among the phytoplankton and zooplankton in the coastal and marine ecosystems [ 1 , 2 , 3 , 4 , 5 , 6 ]. Marine phytoplankton are primary producers in the ocean, forming the base of the marine food web.…”

“…OA affects marine organisms in multiple ways, such as changes in acid-base balance, energy metabolism, redox balance, as well as the behavior of marine organisms [ 9 , 10 , 11 ]. For example, the growth of marine phytoplankton is affected by the increase in CO 2 concentration in seawater [ 2 , 6 , 12 , 13 , 14 , 15 , 16 ].…”