Cascading Effects of Ocean Acidification in a Rocky Subtidal Community

Valentina Asnaghi; Mariachiara Chiantore; Luisa Mangialajo; Frédéric Gazeau; Patrice Francour; Samir Alliouane; Jean-Pierre Gattuso

doi:10.1371/journal.pone.0061978

Risk Assessment for Key Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem Under Combined Ocean Acidification and Warming

Ecosystems ◽

10.1007/s10021-021-00705-w ◽

2021 ◽

Author(s):

Maartje Oostdijk ◽

Erla Sturludóttir ◽

Maria J. Santos

Keyword(s):

Ocean Acidification ◽

Atlantic Cod ◽

Marine Ecosystem ◽

Keystone Species ◽

Ecosystem Model ◽

The Arctic ◽

Predatory Fish ◽

Important Species ◽

Cascading Effects ◽

Icelandic Waters

AbstractThe Arctic may be particularly vulnerable to the consequences of both ocean acidification (OA) and global warming, given the faster pace of these processes in comparison with global average speeds. Here, we use the Atlantis ecosystem model to assess how the trophic network of marine fishes and invertebrates in the Icelandic waters is responding to the combined pressures of OA and warming. We develop an approach where we first identify species by their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We then use literature-determined ranges of sensitivity to OA and warming for different species and functional groups in the Icelandic waters to parametrize model runs for different scenarios of warming and OA. We found divergent species responses to warming and acidification levels; (mainly) planktonic groups and forage fish benefited while (mainly) benthic groups and predatory fish decreased under warming and acidification scenarios. Assuming conservative harvest rates for the largest catch-value species, Atlantic cod, we see that the population is projected to remain stable under even the harshest acidification and warming scenario. Further, for the scenarios where the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase, likely due to a reduction in competition and predation. These results highlight the interdependencies of multiple global change drivers and their cascading effects on trophic organization, and the continued high abundance of an important species from a socio-economic perspective in the Icelandic fisheries.

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Effects of ocean acidification on phenology and epiphytes of the seagrass Posidonia oceanica at two CO2 vent systems of Ischia (Italy)

Mediterranean Marine Science ◽

10.12681/mms.20795 ◽

2020 ◽

Vol 21 (1) ◽

pp. 70

Author(s):

SILVIA MECCA ◽

EDOARDO CASOLI ◽

GIANDOMENICO ARDIZZONE ◽

MARIA CRISTINA GAMBI

Keyword(s):

Ocean Acidification ◽

Posidonia Oceanica ◽

Shoot Density ◽

Control Area ◽

Leaf Length ◽

Coralline Algae ◽

Cascading Effects ◽

Ph Conditions ◽

The Mean ◽

Epiphyte Community

Morphological features of the seagrass Posidonia oceanica (L.) Delile and its epiphyte community were studied in three acidified stations located in two CO2 vents systems and one control station under normal pH conditions off the island of Ischia (Italy) to highlight the possible effects of ocean acidification. Plant phenology was analyzed every two months for a year cycle (June 2016–April 2017), while epiphytes were studied in the period of highest development of both the leaf canopy and the epiphytic community (June, August, and October 2016). The shoot density of Posidonia beds in the acidified stations of the studied sites was significantly higher than that in the control area. Significant differences in the mean leaf length according to the pH condition, month, and the interaction of these two factors were observed (PERMANOVA); the mean leaf width differed also among pH conditions and months. We recorded lower leaf lengths and widths in the acidified stations in all the considered months, compared to those in the control station. These differences are consistent with the higher impact of grazing by the herbivorous fish Sarpa salpa observed on the leaves in the acidified stations. However, the overall leaf surface available for epiphytes was similar among stations because of the higher shoot density under ocean acidification conditions. Overall, the composition and structure of the epiphytic community on the Posidonia leaves showed significant differences in relation to acidification: in both acidified sites, all the calcareous forms, both encrusting red algae (Corallinales) and animals (bryozoans, foraminiferans, and spirorbids), disappeared or were strongly reduced, in favor of encrusting or erect fleshy algae, and non-calcifying invertebrates (hydrozoans, tunicates) which dominated the assemblage. Coralline algae are early species in the epiphytic colonization of P. oceanica and therefore their absence can further modify the pattern of leaf colonization by other species. Therefore, the changes found in the epiphyte community in low pH areas could have potential cascading effects on the seagrass trophic network and the functioning of the system.

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

Ecosystems ◽

10.1007/s10021-021-00601-3 ◽

2021 ◽

Author(s):

Serena Zunino ◽

Simone Libralato ◽

Donata Melaku Canu ◽

Giulia Prato ◽

Cosimo Solidoro

Keyword(s):

Ecosystem Services ◽

Ocean Acidification ◽

Food Web ◽

Marine Protected Area ◽

Habitat Degradation ◽

Marine Ecosystem ◽

Ecosystem Model ◽

Posidonia Oceanica ◽

Ecosystem Development ◽

Cascading Effects

AbstractOcean 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.

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Settlement pattern of Posidonia oceanica epibionts along a gradient of ocean acidification: an approach with mimics

Mediterranean Marine Science ◽

10.12681/mms.677 ◽

2014 ◽

Vol 15 (3) ◽

pp. 498 ◽

Cited By ~ 36

Author(s):

L. DONNARUMMA ◽

C. LOMBARDI ◽

S. COCITO ◽

M.C. GAMBI

Keyword(s):

Ocean Acidification ◽

Posidonia Oceanica ◽

Settlement Pattern ◽

Low Ph ◽

Ph Gradient ◽

Artificial Substrates ◽

Coralline Algae ◽

Cascading Effects ◽

Epiphyte Communities ◽

Ph Conditions

Effects of ocean acidification (OA on the colonization/settlement pattern of the epibiont community of the leaves and rhizomesof the Mediterranean seagrass,Posidoniaoceanica, have been studied at volcanic CO2vents off Ischia (Italy), using “mimics”as artificial substrates. The experiments were conducted in shallowPosidoniastands (2-3 m depth), in three stations on the northand three on the south sides of the study area, distributed along a pH gradient. At each station, 4 rhizome mimics and 6 artificialleaves were collected every three months (Sept 2009-Sept 2010). The epibionts on both leaf and rhizome mimics showed clearchanges along the pH gradient; coralline algae and calcareous invertebrates (bryozoans, serpulid polychaetes and barnacles) weredominant at control stations but progressively disappeared at the most acidified stations. In these extremely low pH sites theassemblage was dominated by filamentous algae and non calcareous taxa such as hydroids and tunicates. Settlement pattern onthe artificial leaves and rhizome mimics over time showed a consistent distribution pattern along the pH gradient and highlightedthe peak of recruitment of the various organisms in different periods according to their life history.Posidoniamimics at theacidified station showed a poor and very simplified assemblage where calcifying epibionts seemed less competitive for space. Thisprofound difference in epiphyte communities in low pH conditions suggests cascading effects on the food web of the meadow and,consequently, on the functioning of the system

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