Patuxent River

Benthic community degredation in the Patuxent River appears to be related to adverse effects from low dissolved oxygen, although other factors also influence benthic community condition in this system. The intensity of summer hypoxic events varies annually, and this variability is reflected in the B-IBI. Over the 1995-2003 time series, benthic community degredation in the Patuxent River, as measured by the B-IBI, was higher in the last four years than in previous years (chart below). The frequency of low dissolved oxygen events was higher in 2000, 2001, and 2003. In 2002, hypoxia was not as severe, and this is noted in the relatively lower percentage of benthic condition in the severely degraded category.