Ocean acidification and warming are predicted to affect the ability of marine bivalves to build their shells, but little is known about the underlying mechanisms. Shell formation is an extremely complex process requiring a detailed understanding of biomineralization processes. Sodium incorporation into the shells would increase if bivalves rely on the exchange of Na+/H+ to maintain homeostasis for shell formation, thereby shedding new light on the acid-base and ionic regulation at the calcifying front.
There is a long history of examining the impacts of nutrient pollution and pH on coral reefs. However, little is known about how these two stressors interact and influence coral reef ecosystem functioning. Using a six-week nutrient addition experiment, we measured the impact of elevated nitrate (NO−3) and phosphate (PO3−4) on net community calcification (NCC) and net community production (NCP) rates of individual taxa and combined reef communities.
Due to the elevated atmospheric carbon dioxide, ocean acidification (OA) has recently emerged as a research theme in marine biology due to an expected deleterious effect of altered seawater chemistry on calcification. A system simulating future OA scenario is crucial for OA-related studies. Here, we designed an OA-simulated system (OASys) with three solenoid-controlled CO2 gas channels. The OASys can adjust the pH of the seawater by bubbling CO2 gas into seawaters via feedback systems.
Marine acidification will be an important environmental problem in the near future as a result of persistent emissions of CO2 and dissolution into seawater. In this study, we found that calcification and respiration of the Zhikong scallop (Chlamys farreri) are likely to be severely affected by increasing acidification. Calcification and respiration significantly declined as pH decreased. The calcification rate decreased by 33% when the pH of water was 7.9 compared with a pH of 8.1, and decreased close to 0 when the pH was reduced to 7.3.
Several studies have demonstrated that shellfish calcification rate has been impacted by ocean acidification. However, the carbonate system variables responsible for regulating calcification rate are controversial. To distinguish the key variables, we manipulated a seawater carbonate system by regulating seawater pH and dissolved inorganic carbon (DIC). Calcification rates of juvenile blue mussel (Mytilus edulis) and Zhikong scallop (Chlamys farreri) were measured in different carbonate systems.
Cryptic colouration in crustaceans, important for both camouflage and visual communication, is achieved through physiological and morphological mechanisms that are sensitive to changes in environmental conditions. Consequently, ocean warming and ocean acidification can affect crustaceans' biophotonic appearance and exoskeleton composition in ways that might disrupt colouration and transparency.
Background Recent reviews suggest that the warming and acidification of ocean surface waters predicated by most accepted climate projections will lead to mass mortality and declining calcification rates of reef-building corals. This study investigates the use of modeling techniques to quantitatively examine rates of coral cover change due to these effects. Methodology/Principal Findings Broad-scale probabilities of change in shallow-water scleractinian coral cover in the Hawaiian Archipelago for years 2000–2099 A.D.
Corals build their skeletons using extracellular calcifying fluid located in the tissue-skeleton interface. However, the mechanism by which corals control the transport of calcium and other ions from seawater and the mechanism of constant alkalization of calcifying fluid are largely unknown. To address these questions, we performed direct pH imaging at calcification sites (subcalicoblastic medium, SCM) to visualize active pH upregulation in live aposymbiotic primary coral polyps treated with HCl-acidified seawater.
Acidification of seawater owing to oceanic uptake of atmospheric CO2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns regarding its adverse effects on corals and calcifying communities. Here we demonstrate a net loss of calcium carbonate (CaCO3) material as a result of decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (n=3) incubated in continuous-flow mesocosms subject to future seawater conditions.
Understanding how calcification is influenced by the enhanced dissolution of CO2 in the oceans is the key to evaluating the effects of ocean acidification (OA) on coral reefs. In this study, two branching hermatypic corals widely distributed in the South China Sea, Pocillopora damicornis and Seriatopora caliendrum, were used to study the calcification responses to CO2-driven OA (7.77 ± 0.07 vs. 8.15 ± 0.12). Our results showed that the calcification rate (0.17 ± 0.04%/day to 0.21 ± 0.12%/day) in P. damicornis remained unchanged in the acidified seawaters, but that in S.
Stable oxygen and carbon isotope measurements on biogenic calcite and aragonite have become standard tools for reconstructing past oceanographic and climatic change. In aquatic organisms, super(18)O / super(16)O ratios in the shell carbonate are a function of the ratio in the sea water and the calcification temperature. In contrast, super13C/ super(12)C ratios are controlled by the ratio of dissolved inorganic carbon in sea water and physiological processes such as respiration and symbiont photosynthesis.
Despite the heightened awareness of ocean acidification (OA) effects on marine organisms, few studies empirically juxtapose biological responses to CO2 manipulations across functionally distinct primary producers, particularly benthic algae. Algal responses to OA may vary because increasing CO2 has the potential to fertilize photosynthesis but impair biomineralization. Using a series of repeated experiments on Palmyra Atoll, simulated OA effects were tested across a suite of ecologically important coral reef algae, including five fleshy and six calcareous species.
As atmospheric concentrations of CO2 rise, the pH of high-latitude oceans is predicted to decrease by 0.3 to 0.5 units by 2100. Several biological consequences of ocean acidification across this pH range have already been documented in invertebrates and tropical marine fishes. However, little work has been done examining potential responses of the temperate and boreal marine fish species that support major fisheries. In 2 experiments, we examined the growth responses of juvenile walleye pollock Theragra chalcogramma at ambient and 3 elevated CO2 levels.
The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how seawater pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO2 and CO32− to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO2 on calcification and dissolution processes.