Hi there, I guess it would depend on how you define short term, or what you mean with short term. How is short term hypoxia in your system? hours, days? Hard to say something about morphology, but physiologically it will depend on whether your species are adapted to hypoxic conditions, like under oxigen decreasing conditions they can activate anaerobic metabolisms pathways, so you can check on that enzimatic activity. No adapted species would simply avoid hypoxic conditions moving away from the site. Again, I guess it depends how short is the exposure to hypoxic conditions.

Dear Aldo thank you for your answer, the short of exposure is couple of weeks to one month time in coastal ocean.

I know for sure a study were the authors examined the prey comsuption of cancrid crabs under normoxic and hypoxic conditions. The experiment was run for a few days. Crabs under hypoxic conditions reduced their comsuptions of prey (bivalves) or either preyed on smaller prey. So thats a behavioral response. In terms of physiological stress you could check for DNA damage or you could check for pyruvate oxidoreductases enzymes as part of metabolic responses during hypoxia. Even at short term those reactions would probably be notice.

Ok Aldo thank you for your valuable suggestion i could check.

Thank you very much Sir

Here is the paper I mentioned, it is in spanish (there are probably lots of papers in english but this one is the one I have at hand) but figures legends are english so you could get it.

Thank you Aldo

I have a paper that might be interesting for you:

McClatchie et al. 2010. Oxygen in the Southern California Bight: Multidecadal trends and implications for demersal fisheries. Geophysical research letters, 36: 1-5.

Hi Naidu

There are plenty of possible physiological and behavioral responses from biota under hypoxia events, including the short-term conditions you mention.

There is a good review paper on effects from hypoxia by Vaquer-Sunyer & Duarte (2008). I have used it as a dataset for SSD (Species Sensitivity Distribution of species) to calculate Effect Factors in Life Cycle Impact Assessment for Marine Eutrophication. In short, the effects identified include:

• Avoidance of hypoxic waters or anoxic sediments, depressed activity, shift to anaerobic metabolism, increased ventilatory water flow, reduced growth, reduced predation rates, lethargy (on fish and crustaceans);

• Reduction of burial depth, climbing on structures (e.g. echinoderms, polychaetes, annelids, crustaceans, gastropods, bivalves, priapulids, and anemones);

• Depression of activity (e.g. echinoderms);

• Reduced feeding activity (e.g. some crustaceans, molluscs, and polychaetes);

• Reduced metabolic rates (e.g. cnidarians) and heartbeat rate (some crustaceans);

• Temporary shifts to anaerobic metabolism (e.g. bivalves, polychaetes, oligochaetes, echinoderms, and some crustaceans).

You can find more details in the paper and you can also check my stuff on Marine Eutrophication to get a glimpse of a good application of the data into Effect Factors.

Cheers

NC

Thank you Molina

Thank you very much Cosme