| Variations in biomass, morphology, and carbohydrate (sugar and starch) reserves in the surfgrass Phyllospadix torreyi were examined in response to manipulations of sediment depth and changes of season. Total biomass, leaf biomass, leaf surface area, sugar concentrations and total carbohydrates varied significantly with season. These changes were typical of those observed in other seagrasses, and were probably caused by changes in light availability. Distributions of sugars shifted between above and below ground tissues on a seasonal basis, but rhizomes appeared to be the primary storage organ.;Experimental manipulations of sediment depth significantly influenced growth and carbohydrate reserves. Plants in 12 cm of sediment had less leaf area, effectively reducing photosynthetic area per plant. Thus decreases in plant biomass and carbohydrate stores may have been due to enhanced root anaerobiosis. Although surfgrass survives natural, seasonal shifts in sediment depth, these results suggest that distribution and abundance of surfgrass beds may be affected by changes in sedimentation and erosion. |
