A brown seaweed (Fucus vesiculosus) grew more slowly in ocean acidification conditions. Consumption of the seaweed by an isopod (Idotea emarginata) was not affected by ocean acidification or temperature. However, reduced growth of the seaweed at high CO2 concentrations might reduce its capability to recover from intense herbivory.

In green sea urchins from the Baltic Sea, the spines appear to be vulnerable to ocean acidification, which might reduce the urchins' protection against predators. Intestinal epithelia may play a role in mediating acid-base balance in the urchin. (Laboratory study)

Sea stars collected in Nova Scotia, Canada, grew more slowly under ocean acidification conditions, and their growth rate decreased further with a warmer temperature. In contrast, blue mussel grew more quickly with no response to temperature within the tested range. Predation of sea stars on mussels, measured as per-capita consumption ...

Under extreme ocean acidification conditions (pH 6.8), the egg production rates of copepods decreased significantly. For two species of sea urchins, fertilization rate of eggs decreased with increasing ocean acidification conditions. Furthermore, the size of urchin larvae decreased and deformities increased. These effects on marine life could lead to changes ...

Muscle length and claw strength of green crabs decreased after the crabs had been in ocean acidification conditions (pH 7.7) for 5 months. Periwinkles tended to have weaker shells in response to acidification. Predation by green crabs on periwinkles did not appear to change under ocean acidification conditions. (Laboratory study) ...

Normally, common periwinkles produce thicker shells in the presence of crab predators. This study found that they did not do so when living in acidified seawater for 15 days. The snails apparently compensated for their lack of defensive shell-building by moving more to avoid the crabs. In a ...

Calcification rate of pteropods dropped 28 percent at pH levels projected for 2100. This result supports the concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource. (Laboratory study)

When larvae of Mediterranean pteropods were cultured in pH 7.82 water, they had malformations and less shell growth. At pH 7.51, the larvae did not make shells but survived and showed normal development. In a natural setting, the smaller shells or lack of shells would have both ecological and biogeochemical ...

Although pteropods are able to build shells at low aragonite saturation state, the production of their shell appears to be very sensitive to decreased pH. (Laboratory study)

Ocean acidification conditions interfered with the chemoreception, or "smelling", that hermit crabs use to find shells and prey. The hermit crabs moved less, had lower flicking rates of their antennae (a ‘sniffing’ behavior in decapods), and were less successful in locating the odor source. (Laboratory study)