Ocean Acidification Research Lab
The Shannon Point Marine Center (SPMC) has been researching the effects of ocean acidification on marine organisms since 2009. A state-of-the-art on campus experimental research facility allows faculty and students alike to investigate the impacts of ocean warming and acidification on marine ecosystems. Research done at this facility is examining the direct effects of ocean acidification (OA) on vulnerable early life stages of several species such as krill, oyster larvae, geoducks and Dungeness crab larvae that are of economic and ecological importance in the Pacific Northwest. Thanks in large-part to generous grants from The National Science Foundation, SPMC has become a leading voice in this critically important field.
The unique design of the Shannon Point OA laboratory allows scientists to mimic nature itself by maintaining the concentration of carbon dioxide in seawater through air-sea gas exchange. Other methods to add CO2 to seawater, such as bubbling water with CO2 gas or directly adding a strong acid, can be stressful to tiny marine organisms, causing them to behave abnormally or even die. The unique laboratory at SPMC allows scientists to work with these tiny and delicate organisms at the base of the marine food web. At SPMC, organisms in seawater are placed inside boxes that, themselves, sit inside a temperature controlled room. The boxes housing the organisms are supplied with atmospheric gases that are equal in CO2 concentration to the elevated CO2 predictions for the end of this century. It is here where air-sea gas exchange increases the CO2 in the seawater, making the water more acidic.
Facilities and Equipment
In the SPMC OA lab, pCO2 in treatment media can be maintained through air-sea gas exchange, thus mimicking nature and also eliminating stress associated with acidifying techniques that require active water flow or direct bubbling with enriched CO2 gas. Ambient and enriched CO2 gas for experimental water pre-equilibration (for initial water and water changes) is made by stripping compressed (Powerex oilless rotary compressor) ambient air of CO2 using scrubbers (Twin Towers Inc.), and then mixing this CO2-free air with pure CO2 in precise concentrations using mass flow controllers (Sierra International Inc.). Ambient and enriched gasses are bubbled into large volumes of media for 24 h, or until pCO2 of headspace gas equals inlet pCO2 concentration. Experimental containers are held inside air-tight Plexiglass boxes supplied with atmospheric gas of equivalent pCO2 treatment concentration. The CO2 concentration in the gasses are measured using a Li-COR Li-820 CO2 sensor. DIC is measured using SPMC’s Apollo SciTech Model AS-C3 total dissolved inorganic carbon analyzer, and TA using open cell potentiometric titration for total alkalinity. Total DIC and TA are typically used to calculate pCO2 and pH using the program CO2sys (Pierrot et al. 2006), yet at the SPMC OA lab calculated pH is routinely verified by direct spectrophotometric measurement using an Agilent 8453A UV-VIS diode array spectrophotometer. The SPMC OA lab also has a Beckman Z2 Coulter Counter for algal cell counting and several biological incubators (Percival Scientific) are available as part of SPMC’s general laboratory facilities.