Today was (almost) all about ocean acidification! First things first, we had a lecture from Carolyn about ocean acidification (OA) and its consequences for marine life, of course focusing on disease.
Our oceans are (generally) not actually acidic, on average having a pH over 8, which is basic. However, the dissolution of CO2 into the ocean results in the creation of H+ ions, decreasing the pH and essentially “acidifying” the ocean. This can affect many aspects of marine biology, ranging from behavior to reproduction to diseases. Unfortunately, the results of OA are not clear cut and depend on the organism you’re looking at and the aspect of its life you’re interested in. For example, many shell-producing organisms suffer from OA because it’s harder to produce and maintain a shell in acidic conditions (H+ competes with Ca2+ for carbonate ions, forming bicarbonate instead of calcium carbonate). On the other hand, a study by Miller et al (2013, http://onlinelibrary.wiley.com/doi/10.1111/gcb.12259/abstract) found that increased CO2 actually increased reproduction in anemonefish.
Carolyn also shared with us some of her and her colleagues’ research on OA’s trans-generational impacts on mollusc disease. The resounding message was that impacts depend on your study organism and that changes in pH seem to be more problematic of the pH levels themselves. As with everything, it’s complicated!
Lecture was followed by a tour of the OA Lab. The facilities afford researchers a large amount of control on the water chemistry of their studies. The incoming water is quite thoroughly filtered (though not quite enough to filter out viral sized particles, but anyway) and the chemistry (pH, CO2, alkalinity, etc.) are routinely checked. One thing that the facility can’t quite control is the salinity of the water. The system cannot react fast enough to rapid changes in ambient salinity such as rain events. However, they are careful to measure the changes in salinity in case anything goes strangely – in a way it’s like how it’s easier (though not really better) to apologize than to ask for permission. In the end, this illustrates that in science, as with all things that require finite resources, there is a trade off things you can and can’t do. Just as how organisms have trade-offs when dealing with OA and fighting infection!
After our (as usual glorious) lunch, we had another lecture where we explored case studies looking at changes in host susceptibility, resistance, and tolerance. I found case study two particularly interesting – hyperparasitism of RLO in abalone by phage (viruses) improved the outlook for abalone infected by the syndrome. The possibility of phage therapy in combating diseases is fascinating especially in a field where disease management is really difficult.
We closed our day by splitting off to do different things that needed doing – running more PCRs with our sea star and laby primers, setting up our oyster laby experiment (more to come, but in the meanwhile see Amanda’s post), and for me pulling out oysters that may be used to assess levels of sea star wasting disease pathogen in the field. I’m really excited to see where that goes. Who knows, we may get a new tool to study the epizootic!