Maryland Mainstem

Stratum Summary

The Maryland mainstem stratum has the largest extent of severely degraded benthic community condition in the Bay.  In 2003, 2,106 km² were estimated to be degraded as measured by the B-IBI, and 61% of this area (including the deep trough) was severely degraded.  Changes over time were generally small (chart below).  The problem in the Maryland mainstem is hypoxia.  Low DO events are common over the stratum and anoxia is a common feature of the mid-bay deep channel.

Fixed long-term monitoring stations in the Maryland mainstem were established in segment CB4MH to assess impacts from power plants.  The stations are located in shallow sandy habitats and show good benthic community status (marginal for Station 15) and positive significant trends in the B-IBI.

Click on colored areas to see site sampling details.