Seawater carbonate chemistry and Posidonia oceanica epiphytic community composition and mineralogy, supplement to: Cox, T Erin; Nash, Merinda C; Gazeau, Frédéric; Deniel, M; Legrand, Erwann; Alliouane, Samir; Mahacek, Paul; Le Fur, Arnaud; Gattuso, Jean-Pierre; Martin, Sophie (2017): Effects of in situ CO2 enrichment on Posidonia oceanica epiphytic community composition and mineralogy. Marine Biology, 164(5)

DOI

Alterations in seagrass epiphytic communities are expected under future ocean acidification conditions, yet this hypothesis has been little tested in situ. A Free Ocean Carbon Dioxide Enrichment system was used to lower pH by a ~0.3 unit offset within a partially enclosed portion (1.7 m3) of a Posidonia oceanica meadow (11 m depth) between June 21 and November 3, 2014. Leaf epiphytic community composition (% cover) and bulk epiphytic mineralogy were compared every 4 weeks within three treatments, located in the same meadow: a pH-manipulated (experimental enclosure) and a control enclosure, as well as a nearby ambient area. Percent coverage of invertebrate calcifiers and crustose coralline algae (CCA) did not appear to be affected by the lowered pH. Furthermore, fleshy algae did not proliferate at lowered pH. Only Foraminifera, which covered less than 3% of leaf surfaces, declined in manner consistent with ocean acidification predictions. Bulk epiphytic magnesium carbonate composition was similar between treatments and percentage of magnesium appeared to increase from summer to autumn. CCA did not exhibit any visible skeleton dissolution or mineral alteration at lowered pH and carbonate saturation state. Negative impacts from ocean acidification on P. oceanica epiphytic communities were smaller than expected. Epiphytic calcifiers were possibly protected from the pH treatment due to host plant photosynthesis inside the enclosure where water flow is slowed. The more positive outcome than expected suggests that calcareous members of epiphytic communities may find refuge in some conditions and be resilient to environmentally relevant changes in carbonate chemistry.

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2016) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2017-08-31.

Identifier
DOI https://doi.org/10.1594/PANGAEA.880301
Related Identifier https://doi.org/10.1007/s00227-017-3136-7
Related Identifier https://cran.r-project.org/package=seacarb
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.880301
Provenance
Creator Cox, T Erin; Nash, Merinda C; Gazeau, Frédéric; Deniel, M; Legrand, Erwann; Alliouane, Samir; Mahacek, Paul; Le Fur, Arnaud; Gattuso, Jean-Pierre; Martin, Sophie
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Contributor Yang, Yan
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 11028 data points
Discipline Earth System Research
Spatial Coverage (7.323 LON, 43.679 LAT)
Temporal Coverage Begin 2014-04-01T00:00:00Z
Temporal Coverage End 2014-11-30T00:00:00Z