The continental shelf region off the west coast of North America is seasonally exposed to water with a low aragonite saturation state by coastal upwelling of CO2-rich waters. To date, the spatial and temporal distribution of anthropogenic CO2 (Canth) within the CO2-rich waters is largely unknown. Here we adapt the multiple ...

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 ...

Impurities in indicator salts can significantly bias spectrophotometric pH determinations. In this work, two purified sulfonephthalein indicators, meta-cresol purple (mCP) and phenol red (PR), were tested for analysis of freshwater pH on the free hydrogen ion concentration scale. The work presented here is the first parallel comparison with two purified indicators used to ...

This study determined the pH tolerance of the embryonic and larval stages of hard clams and oysters. (Laboratory study)

Estuarine waters are more susceptible to acidification because they are subject to multiple acid sources and are less buffered than marine waters. Consequently, estuarine shell-forming species may experience acidification sooner than marine species although, the tolerance of estuarine calcifiers to pH changes is poorly understood. This study analyzed 23 years ...

The shell calcification rates of small hard clams in five size classes (0.39, 0.56, 0.78, 0.98, and 2.90 mm shell height) decreased with increasingly severe ocean acidification conditions (pH 8.02, 7.64, and 7.41). Clams in the larger sizes were able to deposit new shell material even under corrosive conditions. However, ...

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)

Sea urchin larvae from the Mediterranean Sea survived at higher rates under ocean acidification conditions, but they grew smaller. Warmer temperatures increased survival and growth rates of the larvae. The results suggest that ocean acidification and warming could boost populations of the sea urchin, increasing its impact on shallow Mediterranean ...

Three direct effects of increasing ocean acidification on marine plankton have been recognized: enhanced phytoplankton growth rate, changing elemental composition of primary produced organic matter, and reduced biogenic calcification.

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 ...