Seawater carbonate chemistry and growth, chemical defense (phlorotannins) levels of habitat-forming brown seaweed Fucus vesiculosus

• Main Authors: Kinnby, Alexandra, White, Joel C B, Toth, Gunilla B, Pavia, Henrik
• Format: Dataset
• Language: English
• Published: PANGAEA 2021
• Subjects: Alkalinity; total; Aragonite saturation state; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbon/Nitrogen ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chromista; Coast and continental shelf; Efficiency of photosystem II; Experiment duration; Fucus vesiculosus; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth; Growth/Morphology; Identification; Laboratory experiment; Macroalgae; Nitrogen; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Other studied parameter or process; Partial pressure of carbon dioxide; standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Phlorotannin; Primary production/Photosynthesis; Quantum yield efficiency of photosystem II; Registration number of species; Salinity; Single species; Species; Temperate; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.930754; https://doi.org/10.1594/PANGAEA.930754

Ocean acidification driven by anthropogenic climate change is causing a global decrease in pH, which is projected to be 0.4 units lower in coastal shallow waters by the year 2100. Previous studies have shown that seaweeds grown under such conditions may alter their growth and photosynthetic capacity. It is not clear how such alterations might impact interactions between seaweed and herbivores, e.g. through changes in feeding rates, nutritional value, or defense levels. Changes in seaweeds are particularly important for coastal food webs, as they are key primary producers and often habitat-forming species. We cultured the habitat-forming brown seaweed Fucus vesiculosus for 30 days in projected future pCO2 (1100 μatm) with genetically identical controls in ambient pCO2 (400 μatm). Thereafter the macroalgae were exposed to grazing by Littorina littorea, acclimated to the relevant pCO2-treatment. We found increased growth (measured as surface area increase), decreased tissue strength in a tensile strength test, and decreased chemical defense (phlorotannins) levels in seaweeds exposed to high pCO2-levels. The herbivores exposed to elevated pCO2-levels showed improved condition index, decreased consumption, but no significant change in feeding preference. Fucoid seaweeds such as F. vesiculosus play important ecological roles in coastal habitats and are often foundation species, with a key role for ecosystem structure and function. The change in surface area and associated decrease in breaking force, as demonstrated by our results, indicate that F. vesiculosus grown under elevated levels of pCO2 may acquire an altered morphology and reduced tissue strength. This, together with increased wave energy in coastal ecosystems due to climate change, could have detrimental effects by reducing both habitat and food availability for herbivores.