Warming and acidification effects on planktonic heterotrophic Pico- and Nanoflagellates in a mesocosm experiment

• Main Authors: Moustaka-Gouni, Maria, Kormas, Konstantinos A, Scotti, Marco, Vardaka, S, Sommer, Ulrich
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2016
• Subjects: Baltic Sea; Biomass/Abundance/Elemental composition; Coast and continental shelf; Community composition and diversity; Entire community; Laboratory experiment; Mesocosm or benthocosm; Pelagos; Temperate; Temperature; Type; Identification; Treatment; Sample code/label; Day of experiment; Size fraction; Biomass; Abundance per volume; Ratio; pH; Salinity; Temperature, water; Alkalinity, total; Partial pressure of carbon dioxide water at sea surface temperature wet air; Carbon, inorganic, dissolved; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.873191; https://doi.pangaea.de/10.1594/PANGAEA.873191

We studied the response of the heterotrophic flagellate (HF) community to the combined impact of warming and ocean acidification in a mesocosm experiment with a plankton community from the western Baltic Sea. We performed a quantitative analysis of the response at the level of total biomass and size classes and a semi-quantitative one at the level of individual taxa. Total biomass of HF was significantly lower under higher temperatures while there was no significant effect of CO2. The mean biomass of the picoflagellates did not respond to temperature while the three nanoflagellate size classes (class limits 3, 5, 8, 15 ?m) responded negatively to warming while not responding to CO2. The taxon-level results indicate that heterotrophic flagellates do not form a homogenous trophic guild, as often assumed in pelagic food web studies. Instead, the heterotrophic flagellates formed a ?food web within the food web?. There was a pronounced succession of flagellates leading from a dominance of bacterivores and colloidal matter feeders before the phytoplankton bloom to omnivorous feeders preying upon phytoplankton and heterotrophic flagellates during and after the bloom. This complex intraguild predation patterns probably dampened the response to experimental treatments. : 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 is 2017-03-03.