NOAA-supported scientists announced today that the hypoxic zone in the Gulf is approximately 1,332 square miles, making it the second-smallest zone on record in 40 years of measurement. Hypoxic areas, also called “dead zones,” are areas with little to no oxygen in the water, which can negatively impact fish, shellfish, corals, and aquatic plants by making critical habitat unavailable to bottom species.
The annual hypoxic zone survey was led by scientists at Louisiana State University and the Louisiana Universities Marine Consortium. The survey cruise was conducted aboard the LUMCON research vessel Pelican from July 24-30. Data from the survey is available online for the public.
The measured hypoxic zone is smaller than anticipated this year due to Tropical Storm Bertha passing through on the eve of the cruise. Tropical storm-force winds and high waves churned the water across the cruise area and mixed oxygen-rich surface waters down to the seabed. Although the cruise did not capture the full extent of the zone, years with abnormal weather events help researchers better understand how these events impact the breakup and reformation of hypoxia in the Gulf and ultimately lead to better models and forecasts.
"Measuring the hypoxic zone provides more than just a score card of the Gulf's ocean oxygen levels — it helps us better understand the interconnectivity of our nation’s land, waterways and ocean,” said Timothy Petty, Ph.D., NOAA assistant secretary of commerce for oceans and atmosphere, and deputy administrator. “The data we've gathered from 40 years of measurements in the region will help inform the development of better management strategies upstream as part of our ongoing efforts to mitigate future impacts in the Gulf.”
The information helps scientists and coastal managers understand how low-oxygen events impact the overall growth, reproduction, and habitat usage of key fisheries and help develop mitigation measures to alleviate potential damage to affected commercial and recreational fishing industries and tourism.
University of Illinois Extension partners with the Illinois Environmental Protection Agency and Illinois Department of Agriculture to implement the Illinois Nutrient Loss Reduction Strategy. Illinois is one of 12 states that have developed nutrient strategies to meet the goals of the U.S. EPA Gulf Hypoxia Action Plan. The Illinois NLRS goals are to reduce the nutrient pollution that leaves Illinois via the Mississippi River; and to improve the local water quality of streams, rivers, and lakes for Illinois residents.
Read the full article from NOAA.
Photo: Scientists retrieve the CTD — conductivity, temperature, depth — package of ocean sensors after profiling dissolved oxygen at a station during the Shelfwide Hypoxia Cruise in the Gulf. Image credit: Courtesy of Cassandra Glaspie/LSU.
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