Acid Seas
- as we burn fossil fuels
- carbon dioxide is released in to the air
- tons per day, in fact
- but not all of that gas stays in the atmosphere
- about one quarter of it is absorbed into the oceans
- sounds great right?
- scientists thought so too
- though dissolving carbon dioxide gas in the ocean causes ocean pH to drop significantly
- (pH is a measure of how acidic or basic something is, the lower the pH, the more acidic)
- scientists thought that dissolved chemicals from river rock would keep the pH balanced
- but this process is not enough to buffer the 22 million tons of carbon dioxide that is absorbed into ocean waters every day
- this drastic change in pH has some very noticeable effects on marine biota
- for the last 3.5 billion years, the approximate amount of time that there has been life on earth
- the ocean’s pH has been relatively consistent
- meaning that the organisms that live there have evolved in conditions unlike the ones they are experiencing now
- this rapid increase in acidity has varied effects
- the shells of some animals are already dissolving in the acidic ocean waters
- oysters, mussels, and starfish are having a hard time growing their magnesium-calcite shells
- standing calcium carbonate coral skeletons are being corroded and new growth is hard to come by
- but somehow, plants and algae are doing quite well
- in fact, they’re thriving
- plants use carbon dioxide to fuel photosynthesis
- so large amounts of it do nothing but prompt faster growth
- seagrasses
- the underwater plants that are a key part of coastal ecosystems
- are reproducing faster, growing quicker, and growing taller
- they provide a home for thousands of organisms
- and function as nurseries for larger fish
- the excess acidity is helping them grow
- brown algae is also thriving for the same reasons
So how are we supposed to feel about this? Just because some organisms are benefitting does not mean that we should continue business as usual. More carbon dioxide for plants and algae is great, but the majority of marine organisms are suffering. This situation isn’t even entirely beneficial to plants and algae. Sure, seagrasses are growing faster than ever before, but that higher growth rate is still not enough to compensate for other types of coastal pollution that rapidly diminish their population sizes. Brown algae and other types of non-calcifying algal species are benefiting while other species like coralline algae, that grow calcium carbonate shells, are dwindling. If the non-calcifying types (those who don’t grow calcium carbonate shells) take over, they’ll smother and damage coral reefs, adding yet another barrier to coral ecosystem success.
Every move we make has wide reaching effects, many of which we are still unaware of. The effects of our gas emissions reach from the ozone to the ocean floor. It sounds like it’s time to be more conscious of our actions.
Citation
The Ocean Portal Team. “Ocean Acidification.” Smithsonian Ocean Portal. Smithsonian National Museum of Natural History, n.d. Web. 04 Feb. 2016.
