Quote:
Originally Posted by Duck Butter
it would be very relevant, but it hasn't been found despite decades of oyster research and decades of hypoxic zones
low to no oxygen is low to no oxygen to an oyster whether its in Calcasieu Lake, Sabine Lake, Florida, Delaware, or Japan. Everything else you have been saying is spot on, just leave the hypoxia out of the list of ecosystem services oysters perform is all. You put a fish in a hypoxic zone, it swims away or dies, a shrimp swims away or dies, an oyster does not have that option so it closes up and does not filter feed. There are studies showing oysters get stressed and die during hypoxic conditions, they can't magically filter out phosphorus, nitrogen, and potassium out of the water when they have no oxygen to survive on.
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How many cases have been tested where the oysters are upstream of where the hypoxic zone forms (not actually in it)?
You must have missed this essential feature of the Calcasieu system because you keep mentioning how oysters shut down when oxygen levels drop. The hypoxic zone off of Cameron was not there in late June when Texas A&M scientists measured oxygen levels. It was there in late July when LUMCON scientists sampled the area again. At no time where the waters in the main Calcasieu Estuary hypoxic this summer, but it may be that N, P, C, and algae flowing into the Gulf from the estuary contributed to the size of the hypoxic zone.
Further, it has been estimated that at their peak historical levels, oysters in the Chesapeake Bay completely filtered the water in the bay every 3-4 days.
Since some oyster reefs have been restored, the complete water filtration time is estimated at 300-400 days. Drawing conclusions on the potential to mitigate hypoxia in the Chesapeake Bay seems ill advised when the water filtration by the oysters is only 1% of what is possible.
Calcasieu Lake is much shallower than Chesapeake Bay. The potential exists for oysters in Calcasieu Lake to completely filter the water once per day or more if the oyster reef potential were optimized. Sabine drains a much larger area and inevitably has higher levels of agricultural runoff than Calcasieu. Yet, there is very seldom any hypoxic zone there.