Acidification has sparked discussion about whether regulatory agencies should place coastal waters on the Clean Water Act 303(d) impaired water bodies list. Here we describe scientific challenges in assessing impairment with existing data, exploring use of both pH and biological criteria. Application of pH criteria is challenging because present coastal ...

Appendicularians are free-swimming tunicates that are common in most oceans, coastal waters, and estuaries. They build delicate, gelatinous houses that they use to filter food from the water. This study found that appendicularian abundance increased with ocean acidification, warmer temperatures, and higher nutrient levels. This suggests that appendicularians will play ...

Copepods produced more eggs in warmer temperatures, but the increase was smaller when copepods were simultaneously exposed to warmer temperature and ocean acidification conditions (lower pH). When pH changed between egg production and hatching, fewer eggs hatched. Warmer egg production temperature induced a positive maternal effect and increased the egg ...

The shells of eastern oysters from the Chesapeake Bay dissolved at faster rates when exposed to increasingly severe ocean acidification conditions. Oysters with fresh shells dissolved at the fastest rate, followed by oysters with weathered shells and those with dredged shells. (Laboratory study)

Thermal sensitivity of spider crabs, as indicated by heart rate, rose under increasing levels of ocean acidification conditions. The results suggest a narrowing of the spider crab's thermal window under moderate increases in ocean acidification. (Laboratory study)

The immune responses of grazing isopods (Idotea balthica) in the Baltic Sea dropped by 60 to 80 percent after the isopods were placed in ocean acidification conditions for 20 days. In addition, isopods from a low salinity site, where their health was already compromised, suffered 100 percent mortality when placed ...

Brittlestar arms regenerated 30 percent more slowly under ocean acidification conditions. (Laboratory study)

Brittlestar arms regenerated faster in warmer water. However, they did not do so when the temperature increase was accompanied by ocean acidification conditions. This may have occurred because the brittlestars had to devote more of their energy to maintaining calcium carbonate body parts, as calcium carbonate became undersaturated when the ...

Ten species of zooplankton displayed a range of mortality rates when exposed to ocean acidification conditions. Differences in in swimming behavior, food habits, size, and presence of gills were not significantly related to sensitivity to lowered pH. The results suggest that marine zooplankton are more sensitive than freshwater zooplankton to ...

Four species of copepods differed in their survival, egg production, and egg hatching success when exposed to ocean acidification conditions for 8 days. (Laboratory study)