Hypoxia in the Gulf of Mexico
USGS has monitored streamflow and water quality in the Mississippi River Basin (MRB) for decades. Increasingly, management concerns have focused on delivery of streamflow and nutrients to the Gulf of Mexico because of their influence on the formation and extent of a zone of hypoxic waters in the northern Gulf (Flux and yield estimates for subbasins are important because they provide a means to identify the primary source areas and the relative contributions of both streamflow and nutrients from different parts of the Basin. USGS has made estimates of the delivery of streamflow and nutrients both to the Gulf and for selected subbasins and provided that information for use by managers including the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force. Current flux estimates, along with selected previous estimates, are provided below. As the statistical methods to estimate flux improve, fluxes are recalculated for the period of record to provide a consistent and comparable record of flux through time. Current flux estimates, along with selected previous estimates, are provided below, along with a description of the current monitoring network which will provide improved information in the future.