Determining rates and timing of silica (Si) fluxes in an undisturbed New England salt marsh.

Carey, Joanna

"In March 2010 Joanna was awarded the LL Bean Acadia National Park Research Fellowship which funds her to quantify the rates and timing of silica fluxes in a relatively undisturbed New England salt marsh. Silica is a critical component of salt marsh vegetation, as it maintains cell structure and provides protection from environmental stresses. Research has identified a strong connection between harmful algal blooms (HABs) in coastal systems and silica-limited waters. Because salt marshes are regulators of Si export to the adjacent estuary, understanding marsh Si processes is a critical next step in wetland biogeochemistry. This study will determine a complete silica budget for a salt marsh in Acadia National Park with the goal of better understanding the role of salt marshes in contributing to the retention and export of Si to coastal systems. " " From Discussion: The large quantities of Si found within the various portions of the salt marsh indicate that coastal wetland, and salt marshes in particular, are large reservoirs of Si. Being that salt marshes lie right at the interface between upland terrestrial systems and downstream aquatic systems, understanding Si cycling within coastal wetlands remains an important area of study. Compared to a _‘low nutrient marsh’ in Southern New England, Si levels found in the marsh sediment, porewaters and biomass was significantly higher. The differing levels of Si found within various salt marshes in the region is likely due to differences in geology, climate, local weather patterns (I.e. precipitation levels), and freshwater availability. While the net Si accumulation in the Babson Creek marsh was higher than other marshes studied in the region, the DSi concentrations found in the creek were relatively low. This situation indicates that Babson Creek marsh may be acting as a net Si for Si, whereas other marshes in New England have been found to serve as anet sources of Si to the surrounding estuary at times (Vielliard et al., submitted). It is clear that all marshes do not cycle Si in the same manner and a one-size fits all budget is not appropriate for salt marshes in New England. " The intern on the project also published a summary report of the project that is available at: http://northeastparkscience.wordpress.com/2010/08/16/just-a-small-piece-of-the-larger-puzzle-silica/. STUDY LOCATIONS:/ MOUNT DESERT ISLAND/ Babson Creek Salt Marsh