Cordell Marine Sanctuary Foundation has supported monitoring of oxygen concentrations in the water around Cordell Bank for the past 5 years. This work is essential to understanding patterns of low oxygen in the ocean and the effects it has on marine wildlife – important information for effectively protecting ocean ecosystems.
Oxygen is necessary to support life on Earth, including life in the sea. Hypoxia, or low levels of oxygen, in the ocean can be the result of natural processes and of human activity, particularly climate change. Long-term ocean monitoring indicates oxygen in the ocean has declined since the 20th century and hypoxic zones have proliferated around the world. Marine animals that do not typically experience low oxygen concentrations may not be well-adapted to survive, therefore low oxygen concentrations can result in behavioral changes, stress, or mortality. If long-term, large-scale low oxygen conditions were to occur in Cordell Bank National Marine Sanctuary (CBNMS), it could be devastating to the abundant marine life there.
In 2014, following observation of low-oxygen conditions near shore, CBNMS and Bodega Marine Laboratory (BML) staff worked together to deploy instruments on two moorings on Cordell Bank to measure oxygen concentrations and temperature. Since 2014, more sensors have been added to the moorings and the deployments have been extended for year-round data collection. BML doctoral candidate Kate Hewett (a Nancy Foster Scholarship recipient) is working to maintain the continuous monitoring of oxygen concentrations at Cordell Bank and has analyzed the data already collected. Data show that the oxygen conditions at Cordell Bank are variable, with episodes of mild hypoxia currently lasting from a few days to a few weeks.
Together, the Cordell Marine Sanctuary Foundation, BML, and CBNMS are working to better understand the timing and persistence of hypoxia around Cordell Bank and the effects of these conditions on biological communities. This work will help scientists and sanctuary managers understand how the biodiversity at Cordell Bank may be is impacted by hypoxia and could will inform improved conservation management of the sanctuary.
To read more about this work, please see CBNMS website http://bit.ly/2AW3DxG and ONMS web story: http://bit.ly/2x4GOc6 .
Authors of study: Kate Hewett1, Danielle Lipski2, and John Largier1
1 Bodega Marine Laboratory, University of California, Davis; kmhewett@ucdavis.edu, jlargier@ucdavis.edu
2 Cordell Bank National Marine Sanctuary; Danielle.lipski@noaa.gov