Targetted Monitoring for Dissolved Oxygen: Mapping the Extent of Hypoxia in Narragansett Bay, RI

Christopher F. Deacutis 1, Warren Prell 2, David Murray 2, Emily Saarman 2, Larissa Korhun 2

1 Narragansett Bay Estuary Program, URI Coastal Institute, Narragansett RI, 02882; E-mail deacutis@gso.uri.edu
2 Brown University, Providence RI, 02912 E-mails: dmurray@brown.edu ; Warren_Prell@brown.edu ; Larissa_Korhun@brown.edu ; emily_saa@hotmail.com

A multi-institutional, multi-agency volunteer evening dissolved oxygen survey program was initiated by the Narragansett Bay Estuary Program in 1999, and continued through summer 2003. Over these last five years, approximately monthly (summer) vertical water column profiles of temperature, salinity, and dissolved oxygen (concentration and percent saturation) were taken at over 75 stations (mean min. distance between adjacent stations 0.8 ± 0.4 km) distributed throughout the upper half of Narragansett Bay by 6-7 small (20-22') boats. Stations were stratified by depth (<8m, ³8m) and dates for all surveys were specifically targeted for maximum hypoxia risk periods (summer neap tides, evening hours). Underlying reasons for targeting of worst case conditions and maximum use of cost-effective sampling equipment will be discussed, along with a presentation of general repetitive hypoxia patterns and what we have learned from these surveys about hypoxia dynamics in Narragansett Bay.

Keywords: Hypoxia, Monitoring Coastal Conditions, Narragansett Bay U.S., Estuaries, Dissolved Oxygen, Spatial and Temporal Variations, Monitoring Design.

Targetted Monitoring for Dissolved Oxygen: Mapping the Extent of Hypoxia in Narragansett Bay, RI

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