Impact of Ocean Acidification on Ecosystem Functioning and Services in Habitat-Forming Species and Marine Ecosystems

Serena Zunino,Donata Melaku Canu,Simone Libralato,Cosimo Solidoro,Giulia Prato

doi:10.1007/s10021-021-00601-3

Serena Zunino, Donata Melaku Canu + Show 3 more

Open Access

https://doi.org/10.1007/s10021-021-00601-3

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Abstract

Ocean acidification (OA) is expected to impact habitat-forming species (HFS), with cascading effects on the whole marine ecosystem and related services that are seldom quantified. Here, the changes in HFSs biomass due to OA are modeled using a food web ecosystem model, and the trophic and non-trophic cascading effects on the marine community are investigated. The food web model represents a well-studied coastal marine protected area in the NW Mediterranean Sea where coralligenous reefs and Posidonia oceanica meadows constitute important HFS. The model is used to implement 5 scenarios of habitat degradation, that is, reduction of HFS biomass, induced by increasing OA and to quantify the potential changes in ecosystem properties and indicators of ecosystem services over the next 100 years. The changes in ecosystem indicators highlight a decrease in the size of the system and a reorganization of energy flows suggesting a high degree of ecosystem development. All the proxies for ecosystem services show significant decreases in their values. Although representing only a portion of the possible impacts of OA, the findings are consistent with the idea that ecological systems can react to OA effects to maintain the level of ecosystem development, but the new organization might not be optimal from an anthropocentric viewpoint.

Highlights

Global changes are resulting in progressive modification of relevant oceanographic characteristics, such as ocean temperature and currents, and the acidification of global oceans (IPCC 2019)
The simultaneous reductions in seagrass and coralligenous habitat-forming species (HFS) modeled through 100 realizations for each of the 5 scenarios obtained by decreasing their biomass by 10%, 30%, 50%, 70% and 90% resulted in cascading effects that significantly altered ecosystem biomass
We explored the potential effects of habitat loss due to Ocean acidification (OA) by implementing a new parametrization within a mathematical food web model and describing the decrease in HFS biomass, the cascading potential trophic and nontrophic effects on other species, the related consequences in terms of ecosystem structure and functioning, and eventually the loss of ecosystem services

Summary

Introduction

Global changes are resulting in progressive modification of relevant oceanographic characteristics, such as ocean temperature and currents, and the acidification of global oceans (IPCC 2019). Given the importance of goods and services that marine ecosystems provide to humankind, it is relevant to evaluate the implications of global modifications in ecosystem functioning for socioeconomic systems and human well-being (IPBES 2019). The comprehensive evaluation of all the effects induced by climate change is an overwhelming task, the quantification of effects induced by a specific pressure on key sensitive species and related cascading effects might provide an opportunity to quantify the implications of such relevant global impacts. Our study focuses on the Mediterranean Sea, which is a basin that is considered very sensitive to global changes (Giorgi 2006) and to a variety of intense human pressures (Micheli and others 2013) and might be considered a miniature ocean, since most of the processes that occur in the global ocean take place here but at smaller and faster space/time scales (Bethoux and others 1999; Crise and others 1999; Lejeusne and others 2010)

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