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| Submitter's Name |
Savanna Barry |
| Session Name |
Poster Session - Coastal Waters |
| Poster Number |
9 |
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| Author(s) |
Savanna Barry, University of Florida, Fisheries and Aquatic Sciences (Presenting Author) |
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Charles Jacoby,
University of Florida, Soil and Water Science |
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Thomas Frazer, University of Florida, School of Natural Resources and Environment |
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Seagrass resilience to shading driven by biomass allocation ratio |
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Seagrasses are unique marine plants with fully developed leaves, roots and rhizomes and a high degree of phenotypic plasticity in allocating tissue to these structures. Along Florida’s Gulf coast, concentrations of chlorophyll-a in surface waters and the widths and lengths of leaves of the dominant seagrass, Thalassia testudinum, increased along a gradient of increasing phosphorus concentrations in the water column. Aboveground to belowground biomass ratios (AG:BG) for T. testudinum indicated that seagrasses allocated relatively more biomass to aboveground structure as phosphorus concentrations in the water column increased. Based on these results, we designed an 8-week shading-recovery experiment in T. testudinum meadows with three different AG:BG ratios (high, intermediate, and low) to determine if relative allocation of biomass influenced resilience to short-term shading. Seagrasses in all treatment plots persisted through the 5 weeks of shading, but responded negatively to shading by decreasing leaf growth rates or altering leaf morphology. A 3-week recovery period showed that T. testudinum with intermediate AG:BG ratios were more resilient to shading than T. testudinum with either high or low ratios, and seagrasses with high AG:BG ratios were the least resilient. Overall, these results suggested that long-term water quality conditions may exert a strong influence on allocation of biomass by T. testudinum, which potentially may affect their ability to recover from short–term disturbances. In turn, AG:BG ratios are important metrics to monitor in seagrass meadows because they indicate areas of high and low resilience to short-term disturbances. |
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