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Effects of Hypoxia on Survival and Growth of Barnacle Larvae Off the Oregon Coast Amanda Amstutz Department of Zoology Dr. Bruce Menge Dafne Eerkes-Medrano Department of Zoology HYPOXIA: Dissolved oxygen concentrations of less than 1.4 ml /L
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Effects of Hypoxia on Survival and Growth of Barnacle Larvae Off the Oregon Coast Amanda Amstutz Department of Zoology Dr. Bruce Menge Dafne Eerkes-Medrano Department of Zoology
HYPOXIA: Dissolved oxygen concentrations of less than 1.4 ml /L • Hypoxia can cause mass die offs of marine life in areas known as DEAD ZONES
Hypoxia off the Oregon Coast • Hypoxia in shallow waters • (50m or less) was first documented • in the summer of 2002 and has • occurred every summer from 2002-2007
A healthy rockfish reef before 2006 anoxia (left) and after 2006 anoxia (right). Hypoxia off the Oregon Coast
Barnacles! • Barnacles are found on hard substrata in coastal regions • They are filter feeders • Barnacles have a total of eight life stages • Seven of these life stages are open-ocean larval forms www.microscopy-uk.org.uk/mag/imgjan99/naup.jpg
Barnacles are important as: Ecological engineers Prey Because barnacles are ecologically important species, fluctuations in barnacle populations effect entire ecosystems. Photos courtesy Dr. Mark Hixon
Research Goals:1. Determine mortality of larvae at increasingly severe levels of hypoxia for a given exposure period2. Determine if exposure to hypoxic conditions effects growth of larvae Rear barnacle larvae in the laboratory Expose larvae to hypoxia Measure survival Monitor growth and development
Predictions: • Due to the historical lack of hypoxia close to shore, barnacle larvae are predicted to experience high mortality when exposed to hypoxia • Larvae are predicted to experience increased mortality with increasing severity of hypoxia and duration of exposure • Larvae are predicted to have slower growth rates when they have been exposed to hypoxia
Preliminary Results Cumulative mortality of Balanus glandula mixed stage larvae through a six day period after exposure to microxia (0.5 mg/l dissolved oxygen) or normoxia (5 mg/L dissolved oxygen) for 24 hours. (Means ±SD; normoxia n=3; microxia n=3 )
What’s Next • Ensure errors in system have been corrected • Perform 48 and 72 hour trials • Monitor development and growth
Acknowledgements • Howard Hughes Medical Institute • OSU University Honors College • Dr. Kevin Ahern • Dr. Bruce Menge and Dafne Eerkes-Medrano • Hatfield Marine Science Center • Dr. Chris Langdon