Chesapeake Bay Water Clarity: Challenges and Successes

The Chesapeake Bay is a large estuarine system spanning multiple jurisdictions and serves as a model for estuarine health worldwide. Historically, nutrient loading degraded water quality, prompting the need for regulation. Water clarity, one component of water quality, is vital for benthic communities and serves as a key indicator of overall ecosystem health. Here, physical resuspension and salinity gradients, nutrient and sediment inputs, production of organic detritus by phytoplankton, and benthic communities all interact to drive clarity patterns, with high spatial variability. Trends over the last 40 years show improvement, though with a temporary increase in organic detritus in response to reduced sediment inputs and algal release from light limitation. Continued reductions in nutrient and sediment inputs have led to improved clarity across all metrics and a re-expansion of submerged aquatic vegetation. Future management should continue reductions in nutrient and sediment inputs while addressing climate-related shifts in estuarine dynamics.