Food availability outweighs ocean acidification effects in juvenileMytilus edulis: laboratory and field experiments.

Thomsen, Jörn, Casties, Isabel, Pansch, Christian , Körtzinger, Arne and Melzner, Frank (2013) Food availability outweighs ocean acidification effects in juvenileMytilus edulis: laboratory and field experiments. Open Access Global Change Biology, 19 (4). pp. 1017-1027. DOI 10.1111/gcb.12109.

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Supplementary data:


Ocean acidification is expected to decrease calcification rates of bivalves. Nevertheless in many coastal areas high pCO2 variability is encountered already today. Kiel Fjord (Western Baltic Sea) is a brackish (12-20 g kg-1) and CO2 enriched habitat, but the blue mussel Mytilus edulis dominates the benthic community. In a coupled field and laboratory study we examined the annual pCO2 variability in this habitat and the combined effects of elevated pCO2 and food availability on juvenile M. edulis growth and calcification. In the laboratory experiment, mussel growth and calcification were found to chiefly depend on food supply, with only minor impacts of pCO2 up to 3350 μatm. Kiel Fjord was characterized by strong seasonal pCO2 variability. During summer, maximal pCO2 values of 2500 μatm were observed at the surface and >3000 μatm at the bottom. However, the field growth experiment revealed seven times higher growth and calcification rates of M. edulis at a high pCO2 inner fjord field station (mean pCO2 ca. 1000 μatm) in comparison to a low pCO2 outer fjord station (ca. 600 μatm). In addition, mussels were able to outcompete the barnacle Amphibalanus improvisus at the high pCO2 site. High mussel productivity at the inner fjord site was enabled by higher particulate organic carbon concentrations. Kiel Fjord is highly impacted by eutrophication, which causes bottom water hypoxia and consequently high seawater pCO2. At the same time, elevated nutrient concentrations increase the energy availability for filter feeding organisms such as mussels. Thus M. edulis can dominate over a seemingly more acidification resistant species such as A. improvisus. We conclude that benthic stages of M. edulis tolerate high ambient pCO2 when food supply is abundant and that important habitat characteristics such as species interactions and energy availability need to be considered to predict species vulnerability to ocean acidification.

Document Type: Article
Additional Information: WOS:000315900800005
Keywords: Ocean acidification; seawater; field study; Mytilus edulis; CO2 enriched ecosystem; energy availability; Amphibalanus improvisus; community response; calcification; adaptation; eutrophication; carbon-dioxide concentration; co2-rich coastal habitat; acid-base-balance; larval development; shell growth; mussel; invertebrates
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
Refereed: Yes
Open Access Journal?: No
Publisher: Wiley
Projects: BIOACID, Future Ocean
Date Deposited: 11 Dec 2012 08:46
Last Modified: 23 Sep 2019 18:41

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