Seawater carbonate chemistry, structural and chemical characteristics of the seagrass Thalassia testudinum in an situ CO2 enrichment experiment

• Main Authors: Campbell, Justin E, Fourqurean, James W
• Format: Dataset
• Language: English
• Published: PANGAEA 2013
• Subjects: Alkalinity; total; Aragonite saturation state; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbohydrates; non structural; standard error; Carbon; inorganic; dissolved; Carbon/Nitrogen ratio; Carbon/Phosphorus ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); EXP; Experiment; Field experiment; Florida_Keys; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Identification; Incubation duration; Leaf; growth rate; Leaf area per shoot; Mass per shoot; Nitrogen/Phosphorus ratio; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.824407; https://doi.org/10.1594/PANGAEA.824407

Seagrasses commonly display carbon-limited photosynthetic rates. Thus, increases in atmospheric pCO2, and consequentially oceanic CO2(aq) concentrations, may prove beneficial. While addressed in mesocosms, these hypotheses have not been tested in the field with manipulative experimentation. This study examines the effects of in situ CO2(aq) enrichment on the structural and chemical characteristics of the tropical seagrass, Thalassia testudinum. CO2(aq) availability was manipulated for 6 months in clear, open-top chambers within a shallow seagrass meadow in the Florida Keys (USA), reproducing forecasts for the year 2100. Structural characteristics (leaf area, leaf growth, shoot mass, and shoot density) were unresponsive to CO2(aq) enrichment. However, leaf nitrogen and phosphorus content declined on average by 11 and 21 %, respectively. Belowground, non-structural carbohydrates increased by 29 %. These results indicate that increased CO2(aq) availability may primarily alter the chemical composition of seagrasses, influencing both the nutrient status and resilience of these systems.