Ocean acidification significantly harms calcifying organisms by reducing the availability of carbonate, a vital element for building their structures.
Calcifying organisms, which include marine life like coral and some types of plankton, rely on carbonate ions present in seawater to build their hard parts, such as shells, skeletons, and protective casings. Ocean acidification, caused by the absorption of excess atmospheric carbon dioxide into the ocean, leads to a decrease in the concentration of these crucial carbonate ions.
Key Impacts of Ocean Acidification on Calcifiers
Based on the available information, the primary effects are:
Difficulty Forming Shells and Skeletons
- Ocean acidification reduces the amount of carbonate available in seawater.
- This makes it more challenging and energetically expensive for organisms to extract enough carbonate to build and maintain their shells or skeletons.
- Young or developing organisms may struggle the most, potentially leading to weaker structures or failure to develop properly.
Dissolution of Existing Structures
- As carbonate levels decline and the water becomes more acidic, existing shells and skeletons made of calcium carbonate can begin to dissolve.
- This weakens the protective structures of organisms, leaving them vulnerable.
Organisms Affected
Examples of marine life particularly susceptible include:
- Corals: Their reef structures, built from calcium carbonate, are highly vulnerable to both reduced formation and dissolution.
- Shellfish: Organisms like oysters, mussels, and clams need carbonate to grow their shells.
- Plankton: Some forms of plankton, critical to marine food webs, have calcium carbonate shells (e.g., coccolithophores).
- Crustaceans: While their exoskeletons are not solely calcium carbonate, some parts can be affected.
- Echinoderms: Sea urchins and starfish, which have calcified skeletons, are also impacted.
The reduced ability to calcify weakens these organisms, impacting their survival, growth, and reproductive success. This, in turn, can disrupt entire marine ecosystems that rely on these calcifiers for habitat, food, or structural support.
