The frequency of marine sponges that harbour photosynthetic organisms was examined in a tropical area of the Western Indian Ocean. Out of 77 species from five different habitats in Zanzibar, 55 (71.5%) were found to have photosynthetic activity, as assayed by in situ pulse amplitude modulated (PAM) fluorometry (and validated by measurements of chlorophyll content). A significantly higher percen...

A major dieback of seagrass occurred in South Australia where 12,717 ha of intertidal and shallow subtidal seagrasses were lost along the north eastern coast of Spencer Gulf. This was a rapid decline, occurring toward the end of summer in January or early February of 1993. The extent and location of the dieback was mapped from aerial photographs taken before (1987) and after the event (1994). E...

BACKGROUND Enhanced nutrient loading and depletion of consumer populations interact to alter the structure of aquatic plant communities. Nonetheless, variation between adjacent habitats in the relative strength of bottom-up (i.e. nutrients) versus top-down (i.e. grazing) forces as determinants of community structure across broad spatial scales remains unexplored. We experimentally assessed the ...

Seagrasses are clonal monocots that dominate shallow subtidal coastal and estuarine environments worldwide. They are important for their relatively high productivity and their role in coastal sediment stabilization, as habitat and food for invertebrates, fishes, turtles, dugongs and manatees, and as a source for detrital food webs. Seagrasses grow through the iteration of a vegetative ramet, co...

The fate of nitrogen entering Long Island Sound Embayments is dependent on both volume of submarine groundwater discharge (SGD) and geochemical transformations in the coastal aquifer. Previous work in Stony Brook Harbor revealed the importance of sediment composition in the subtidal and offshore areas of the harbor; SGD rate in the subtidal is higher than offshore areas, but experiences only 30...

Risk of infection by parasites can be driven by environmental heterogeneity, often at small scales. We quantified the effect of tidal elevation on infection patterns of two lethal parasites, Perkinsus marinus and Haplosporidium nelsoni, in an important coastal species, the eastern oyster, Crassostrea virginica. Within the southeastern US, oysters in Georgia and South Carolina are rarely found i...

To assess the spatial structures and temporal evolutions of distinct physical processes on the West Florida Shelf, patterns of ocean current variability are extracted from a joint HF radar and ADCP dataset acquired from August to September 2003 using Self-Organizing Map (SOM) analyses. Three separate ocean– atmosphere frequency bands are considered: semidiurnal, diurnal, and subtidal. The curre...