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Distributions of physical, biological, and chemical parameters in Florida Keys coastal waters seaward of the reef track were surveyed on September 9 to 13, 1993, as part of a coordinated multidisciplinary study of surface transport processes. A band of low-salinity water was observed along the shoreward side of the Florida Current over the downstream extent of the survey from Miami to Key West. Biological and chemical indicators within the band, together with its large volume, satellite imagery, and a surface drifter trajectory suggested the recent Mississippi River flood as the source. Introduction While the 1993 flooding itself received considerable popular attention [Mairson, 1994; Macilwain, 1993a, b] much less consideration has been given to its downstream effects. Upper layer salinities in the Florida Straits region are typically 36 or greater [Wennekens, 1959; Schmitz and Richardson, 1990]. Physical oceanographers have suspected the Mississippi River (MR) as a source of low-salinity water in the Gulf Stream and Florida Straits [Wennekens, 1959; Atkinson and Wallace, 1975; Maul, 1974] but were unable to confirn• their suspicions due to a lack of supporting data. As part of an ongoing regional program [Lee et al. , 1994], the physics, chemistry, and biology of these waters have been studied for the last 5 years. In this paper we relate physical, biological and chemical measurements in an anomalous low-salinity band to satellite advanced very high resolution radiometer (AVHRR) thermal imagery, Argos tracked surface drifter trajectories, and wind records from the Mississippi delta. Together, these data provide convincing evidence of entrainment of MR flood waters into the Gulf of Mexico Loop Current and subsequent transport through the Florida Straits and along the U.S. east coast on the shoreward side of the Gulf Stream.

In August 2007, as part of the NOAA National Marine Fisheries Service (NMFS) West Coast Groundfish Bottom Trawl Survey, we examined the biomass of demersal organisms in a known hypoxic area off the Oregon coast. Although observed each summer, the intensity of hypoxia has varied annually (2002)(2003)(2004)(2005)(2006)(2007) with the greatest temporal and spatial extent noted in 2006. In 2007 we identified the geographic extent of the hypoxic zone and sampled 17 stations along two depth contours (50 and 70 m) within the area. A Sea-Bird SBE 19plus equipped with a dissolved oxygen (DO) sensor was attached to the bottom trawl to monitor oxygen concentration during each tow. Bottom DO concentrations at all stations were hypoxic with means along the tow tracts ranging from 0.43 to 1.27 mL L )1 . Total catch per unit effort (ln CPUE, kg hectare )1 ) and species diversity (number of species, N) were significantly and positively related to oxygen concentration along the hypoxic gradient. In addition, CPUE (natural log-transformed) for eight fish species and five benthic invertebrate species were significantly and positively related to bottom oxygen concentration within the hypoxic region. Condition factors for five fish species, as well as Dungeness crab (Cancer magister) increased with increased bottom oxygen levels along the hypoxic gradient. Historical catch (2003)(2004)(2005)(2006) within the hypoxic zone indicates that biomass was significantly lower in 2006, the year with the lowest bottom DO levels, relative to other years.