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Research in the 1990s demonstrated that more diverse herbaceous plant communities are more productive and exhibit less year-to-year variability in net primary productivity (NPP). Recently, this positive relationship has also been observed in forest communities. New CDR LTER research also indicates that the relationship increases in strength with experiment duration in grasslands. Recent network-wide synthesis… Read more »

Contradicting classical estuary models, FCE LTER research demonstrated that marine nutrient supplies (rather than freshwater nutrient supplies) control coastal productivity gradients via daily tides, episodic storm surges, and hidden groundwater upwelling. Saltwater intrusion amplifies marine pulses by increasing connectivity to the sea and liberating phosphorus from limestone. Sea level projections based on long term data… Read more »

Long term data reveal that multiple types of disturbances — including cold snaps, fires, droughts, floods, and tides — play a strong role in shaping coastal ecosystems. Tropical storms can be beneficial by connecting upstream and downstream food webs and dispersing mangrove propagules into disturbance-generated canopy gaps. They also deliver phosphorus rich mineral deposits that… Read more »

Rising seas can stimulate the inland transgression of mangroves and amplify carbon gains (as observed in historic carbon budgets based on long term flux data, paleoecology, and remote sensing). However, FCE LTER studies, experiments, and models show that carbon losses can exceed increases where saltwater invades freshwater marshes, resulting in abrupt elevation loss (collapse) that… Read more »

Coastal food webs are subsidized by episodic and seasonal connections to upstream detrital food supplies. However, top coastal estuary predators show great individual variation in their ability to capitalize on this subsidy — a finding that has been applied in comparative cross-site research.  

Estuaries are net sources of CO2 to the atmosphere and coastal ocean, and net sinks for oceanic and atmospheric O2. This finding challenges the simplistic treatment of estuaries in global carbon models, and suggests that interactions between river discharge, changes in marsh area, and increasing atmospheric CO2 will alter shelf-ocean carbon exchange in the future…. Read more »

Ammonia-oxidizing archaea (AOA) convert ammonium into nitrite, but little is known about the population dynamics of this relatively new addition to the nitrogen cycle. Research from GCE LTER found that mid summer blooms of AOA coincide with a peak in nitrite concentration. Field data from 29 estuaries showed similar summer peaks in nitrite, suggesting that… Read more »

Sea level rise is expected to cause salt marshes to extend upstream at the expense of freshwater wetlands, dramatically altering the intertidal landscape. Experimental salinization reduces primary production, reduces plant species diversity, decreases respiration, and leads to loss of marsh elevation.  

Long term monitoring, remote sensing, and field experiments showed that dominant estuarine plants grow up to 3 times better in years with low salinities, and that salinity is driven most strongly by river discharge. A high frequency of drought in 1998-2012 led to declines in plant biomass relative to the 28-year period of record for… Read more »

Mobile predators like alligators move between fresh and marine habitats, consume a variety of estuarine prey, and alter the behavior of intermediate predators such as blue crabs. A predator exclusion experiment initiated in 2016 indicated that blue crabs and large fish alter the abundance of marsh invertebrates such as snails and fiddler crabs, which in… Read more »