14 research outputs found
When the twilight of eve dims the sun\u27s last ray [first line]
Performance Medium: Piano and Voice (with lyrics
Seed Reserve Hot Spots for the Sub-Tropical Seagrass \u3ci\u3eHalodule wrightii\u3c/i\u3e (Shoal Grass) in the Northern Gulf of Mexico
© 2020, Coastal and Estuarine Research Federation. Halodule wrightii (shoal grass) is a dioecious seagrass with a widespread tropical and subtropical distribution. Like all seagrass species, H. wrightii has the ability to expand asexually through rhizome elongation and to reproduce sexually through seed. To better understand H. wrightii sexual recruitment dynamics in the northern Gulf of Mexico, we investigated seed bank densities at 815 sites from south Texas to the Florida Panhandle. H. wrightii seed reserves were spatially variable across the region, with seed densities ranging from 0 to 5290 seeds mâ2. Spatial analysis revealed clusters of high seed densities (âhot spotsâ) in Upper Laguna Madre, TX, and Santa Rosa Sound, FL, and clusters of low seed densities (âcold spotsâ) in Lower Laguna Madre and Aransas Bay, TX. Hot spots were dominated by H. wrightii, whereas cold spots were dominated by Thalassia testudinum (turtle grass). We frequently found intact seed coat halves, suggesting germination; however, we also encountered broken seed coat pieces, characteristic of seed predation. Genotypic surveys within and adjacent to seed hot spots revealed genetically diverse adult populations 6 years post seed bank sampling. Our data show that H. wrightii seed reserves are heterogeneous across the northern Gulf of Mexico and that the factors driving variation in seed bank density, viability, and germination remain poorly understood. Information on the spatial heterogeneity of H. wrightii seed densities has relevance for seagrass management, including targeting meadows with high levels of reproductive effort for protection or designation as marine reserves