Effects of in situ CO2 enrichment on the structural and chemical characteristics of the seagrass Thalassia testudinum
- 814 Downloads
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.
KeywordsSeagrass Meadow Shoot Density Shoot Mass Open Plot Thalassia Testudinum
We thank Dr. Patrick Rice and the Florida Keys Community College for logistical support. Rebecca Bernard, Jeana Drake, Pamela Parker, and Bryan Dewsbury provided assistance in the field. This work was supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research Program under Grant No. DBI-0620409, and a Graduate School Doctoral Evidence Acquisition Fellowship awarded by Florida International University. This is contribution number 603 from the Southeast Environmental Research Center at FIU.
- Arnold T, Mealey C, Leahey H, Miller AW, Hall-Spencer J, Milazzo M, Maers K (2012) Ocean acidification and the loss of phenolic substances in marine plants. Plos One 7(4):e35107Google Scholar
- Invers O, Tomas F, Perez M, Romero J (2002) Potential effect of increased global CO2 availability on the depth distribution of the seagrass Posidonia oceanica (L.) Delile: a tentative assessment using a carbon balance model. Bull Mar Sci 71(3):1191–1198Google Scholar
- Kline DI, Teneva L, Schneider K, Miard T, Chai A, Marker M, Headley K, Opdyke B, Nash M, Valetich M, Caves JK, Russell BD, Connell SD, Kirkwood BJ, Brewer P, Peltzer E, Silverman J, Caldeira K, Dunbar RB, Koseff JR, Monismith SG, Mitchell BG, Dove S, Hoegh-Guldberg O (2012) A short-term in situ CO2 enrichment experiment on Heron Island (GBR). Sci Rep 2:413Google Scholar
- Zimmerman RC, Kohrs DG, Steller DL, Alberte RS (1997) Impacts of CO2 enrichment on productivity and light requirements of eelgrass. Plant Physiol 115(2):599–607Google Scholar