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B 134 M: Ocean acidification: Integrated approaches to understanding effects on marine invertebrates

Start date:
Early October
End date:
Mid December
Locations:
Crary Lab, Big Razorback Island, Cape Evans
Principle Investigator:
Dr Gretchen Hofmann
Organisation:
University of California Santa Barbara
Field season overview:
This is the second field season for this project and the activites planned for 2011-2012 are very similar to the fieldwork of the first season. For this season's field activities, researchers have three objectives, all of which involve sea ice travel, the need for research huts on the sea ice, and transportation needs to the field locations. 1. With the support of the RPSC dive team at McMurdo Station, the research team will collect adult sea urchins at a couple sites within the local area. 2. Researchers will deploy pH sensors (SeaFETs) in three McMurdo Sound locations. These deployments will require dive support, but it will be limited, requiring support when the sensors are deployed at the beginning of the season (early October), and then again when the sensors are retrieved at the end of the season (early to mid-December). Based upon last seasons data and activities, the field team will deploy one sensor on the benthos at Cape Evans (where the researchers collect most of the adults that are spawned to support the developmental experiments and create the cultures raised in the lab). They will deploy another sensor further back in the sound near the permanent ice shelf, and one sensor will be deployed at New Harbor in order to characterize the seawater in that area (working with B-043-M (Bowser) to deploy this instrument). Finally, if the sensors hold up, the research team plans to leave one at Cape Evans until February and one field team member will deploy to McMurdo Station to retrieve it with the assistance of support contractor dive personnel. 3. To complement the pH data from the SeaFET, and to calibrate the instrument, researchers will also sample water from one or two locations at McMurdo Station on a nearly daily basis (as weather and sea-ice conditions allow). The water will be processed in the lab for carbonate chemistry.
Researchers plan to study the effects of ocean acidification on embryos and larvae of Antarctic sea urchins. They will raise sea-urchin larvae under high carbon dioxide conditions to mimic the high carbon dioxide, low pH ocean they expect in the future. Researchers will then compare the physiology and response of these experimental larvae to control larvae that have grown in normal conditions. The work will address how the larvae are able to calcify and make their calcium carbonate skeletons at low pH and address how the shape of the skeleton might change. In the lab, researchers plan to prepare samples to assess changes in protein content of the larval skeleton and will prepare RNA samples in order to eventually use a DNA microarray (back at their home institution) to assess patterns of gene expression for genes involved in biomineralization or other important biochemical pathways.