Dissolved nitrogen dynamics in groundwater under a coastal Massachusetts forest.

Abstract

The benthic algal biomass is distributed very patchily throughout each site. As a result, even though six core samples were taken on each sampling day, more samples might be needed to truly estimate the actual biomass of each quadrat. The tremendous variability-not only within each area but also within each quadrat-confounds the algal chlorophyll measurements. It is possible that significant algal growth occurred, but the algae were grazed heavily and thus did not show an actual increase in biomass. It is also possible that our removal of aboveground plant biomass resulted in desiccation of the marsh surface. Desiccation could limit algal growth directly and by preventing the remineralization of nutrients necessary for future algal growth. Regrowth of marsh plants in the hayed site occurred particularly rapidly (to more than 70% of the biomass of an S. patens reference) over the 30 days of the experiment. Thus any stimulation of algal growth by increased light due to haying is likely to be short