The Florida coastal Everglades (FCE) is a coastal wetland, which is characterized by a freshwater to marine gradient ranging from freshwater marshes, through mangrove fringe to the seagrass dominated Florida Bay estuary. Dissolved organic matter (DOM) in this system is am important biogeochemical component as most of the N and P are in an organic form. The dynamics of this DOM in the FCE is complex given its versatile sources and the effects of geomorphology, hydrology, water chemistry, and history of degradation on DOM composition and fate.

Shrubs have displaced grasses throughout much of the world’s arid and semiarid lands (drylands) over the past century. In the Chihuahuan Desert in southern New Mexico, the conversion of black gramma grasslands to mesquite shrublands over the past 100 years has been well documented. The extent to which this displacement of grasses by shrubs has altered leaf litter quality and the spatial distribution of litter inputs and thus nutrient turn over via decomposition is unknown.

Soil microbial communities play a pivotal role in providing ecosystem services, given that they are key drivers of biogeochemical processes such as carbon and nitrogen cycling. As species-rich communities, made-up of populations with short generation times, it is commonly assumed that there is a high degree of functional redundancy within soil communities with respect to broad-physiological processes, such as organic carbon decomposition.

Decomposition is a fundamental driver of biogeochemical cycling that dictates nutrient availability, carbon storage, and community composition. Although mechanistic models of decomposition dynamics have been successfully applied to many different systems, predicting decomposition in drylands has remained problematic due to a poor understanding of the driving variables. A recent study in the Sonoran Desert found a strong positive relationship between decomposition rates and the amount of soil deposited onto litter, which varied by a factor of six as a function of microsite vegetation cover.

The Florida Coastal Everglades (FCE) is an oligotrophic wetland characterized by very low quantities of particulate organic matter (POM). POM in this environment occurs as a slow-moving, benthic layer of flocculent material (floc) that has been defined as biogenic, detrital and rich in organic matter. Although it is known that floc is an important component of the food web in the Everglades, still little is known about its biogeochemical dynamics in this environment. Floc has also been thought to be a potentially important source of dissolved organic matter (DOM).

Reservoirs are common on medium-sized rivers, and understanding their role in algal production is important. Suspended algal growth typically is limited in rivers because of hydrology and turbidity. Dams are particularly interesting because they increase water residence time and allow algae to be produced. The lower Kalamazoo River has two relatively large impoundments at Morrow Lake and Lake Allegan, which increase the production of algae.

Permafrost plays an important role in shaping the chemistry of streams by restricting subsurface flows through catchments to soils. During the summer thaw of soil, subsurface flows migrate through deeper soil horizons presumably resulting in seasonal shifts in the inputs of carbon and nitrogen to the streams. Within streams, the extent of the hyporheic zone may also shift with seasonal thaw. Hyporheic zones have high mineralization and nitrification rates; thus expansion of the hyporheic zone throughout the season has important implications for stream chemistry.