A recent study shows that the Pacific Ocean is becoming so acidic that it’s damaging the sensory organs and dissolving the shells of newly hatched Dungeness crabs from its coastal waters. The Dungeness crabs are vital to commercial fisheries in the Pacific Northwest, and their injuries could affect coastal economies and forecast the complications in a changing sea.
While the results aren’t unexpected, the authors of the study didn’t think the acidity would damage the crabs this fast. “If the crabs are affected already, we really need to make sure we pay much more attention to various components of the food chain before it is too late,” said senior scientist Nina Bednarsek, the study’s lead author.
The study was funded by the NOAA (National Oceanic and Atmospheric Administration) and published in the Science of the Total Environment. The NOAA studies acidification in the ocean and how changing pH levels are affecting coasts.
The Study
An international team of researchers used a scanning electron microscope to study samples of Dungeness crabs collected during an NOAA research cruise in 2016.
They discovered the following:
- The larval Dungeness crabs’ upper shell was damaged.
- Damaged crabs were smaller than other larvae.
- Some of the crabs lost the hair-like sensory structures they’d usually use for navigating.
Why Is The Ocean Acidifying?
The ocean absorbs about 30% of the carbon dioxide (CO2) in the atmosphere. As levels of CO2 in the atmosphere increase, the levels in the seawater do too, which makes the ocean acidic.
According to the NOAA, ocean acidification changes coasts by releasing excess nutrients that can cause algae blooms and increases the sea’s temperature and salinity. It becomes more difficult for coral and crustaceans that rely on carbonate ions to build strong shells and coral skeletons.
However, crabs and coral aren’t the only ones who rely on carbonate ions to strengthen themselves, Oysters, clams, and plankton also do.
Future Plans
With the obstacles a crab larva encounters in its early development, it has less of a chance of making it to adulthood. The researchers plan to investigate further into finding out if the same forces could negatively impact adult Dungeness crabs.
The NOAA suggests two methods of attack; teaching people who rely on carbon about how it affects the sea or reducing overall carbon footprint to lessen the CO2 absorbed by the sea which causes ocean acidification.
