Threats

Point Source² Nutrient Pollution from
-Sewage
-Water Runoff, fertilizer from lawns
-Coastal Septic Systems
-Wastewater treatment plant discharges

Algae Blooms
-A normal cyclical event in the Bay, explosive blooms can occur in response to excess nitrogen and increased water temperatures, lasting much longer than usual.  They compete with eelgrass for sunlight and nutrients.   

Bioturbation
– Changes in physical soil qualities caused by bottom dwelling fauna.  Burrowing, digging activities can expose eelgrass roots to grazers or uproot the plant entirely.             

Climatological Change
-Sea level rise can kill off eelgrass in deeper waters with insufficient light penetration
-Increased water temperatures reduce viable eelgrass habitat and may increase predation³ by certain species.
-Rapid climate change may stress eelgrass beds to the point of die-off before they can adapt to new changes.

Human Activities
-Shell fishing: Raking and digging for shellfish can uproot and kill eelgrass shoots. 
-Boating Activities: Propellers can dig up shallow beds of eelgrass, leaving long scars of unvegetated area within a bed.  Anchors, when dropped into an eelgrass bed, can dredge up shoots.

Both human activities can create large open areas within a bed, leaving it vulnerable to predation³.   

Wasting Disease
-The last major event was recorded in 1931 and wiped out approximately 90 percent of existing eelgrass in North America.  Caused by a slime mold, this disease can have devastating effects when populations of eelgrass are stressed and susceptible to infection. 

 

² - Point-source pollution is pollution that can be traced back to a single origin or source such as a sewage treatment plant discharge.
³ - Predation is a relation between organisms in which one organism captures and feeds on others