Wetland ecology

The relative rates of detrital decomposition in four vegetation communities within the Everglades' ridge-slough microtopography were evaluated during two trials. Litterbags with community-specific detritus in proportion to each community's composition were put into the four communities; namely, submerged marsh, emergent marsh, short Cladium ridge, and tall Cladium ridge. These litterbags were paired with litterbags containing control leaf litter from Chrysobalanus icaco and Salix caroliniana during the wet and dry season trials, respectively. No regional differences in decomposition were shown, but there were significant differences across communities, attributed to the initial C:N ratio of the detritus, with the fastest decomposition occurring in the deepest submerged marsh followed by emergent marsh, and the shallower ridge communities had equally slower decomposition. Additionally, both controls followed the same pattern. Thus, decomposition contributes to an active self-maintenance mechanism within the vegetation communities which ultimately helps to conserve the ridges and sloughs.

Sorites dominicensis is a common Foraminifera living on Thalassia testudinum seagrass blades in the Indian River Lagoon. This locality is unique because epiphytic diatoms, characteristic of Caribbean and temperate environments, are expected to make up the biofilm community. Diatoms compose a large part of the Foraminiferan diet. It is important to understand the cause and effect relationship of population variation between S. dominicensis and its preferred food source, since both are valuable bioindicators. We examined the selective feeding of S. dominicensis by first, identifying the diatom assemblage. Second, we utilized scanning electron microscopy (SEM) in order to identifying the remains of diatoms entrapped in pseudopodial nets and in debris piles. We found that Mastogloia and Cocconeis were the most prominent genera in the overall diatom assemblage. The food preference of S. dominicensis included Amphora, Berkeleya rutilans,Cocconeis, Licmophora dalmatica, Mastogloia, Odontella rhombus, Plagiogramma pulchellum var. pygmaeum, and Skeletonema.