Increasing Ocean Acidification

…and here’s another gloomy ramification of climate change.

A big threat from climate change to the marine ecosystem is the increasing ocean acidification. When carbon dioxide is released into the atmosphere, 30–40% of it is absorbed by the oceans. Because of this, oceans, which are naturally alkaline, are becoming acidic over time. Since the start of the industrial revolution, the pH of the world’s oceans has fallen from 8.2 to 8.1. This has led to disastrous consequences for the marine ecosystem (and especially the corals).

Weaker Coral Skeletons

This increased acidity interferes with the process of skeleton making of the corals. The skeleton is critical to the existence of the coral reefs as it is their building block. Ocean acidification causes the amount of calcium carbonate in seawater to fall. It makes it more difficult for coral reefs to rebuild and grow their skeletons. This increases the chances of coral death.

Coral Bleaching

The intensity and frequency of ocean acidification, and hence coral bleaching, has never been this severe (at least since the last 300 million years). Coral bleaching occurs when the temperature rises. Because of this, the algae that live on the coral tissues, giving them their color, begin to die, leaving behind the coral skeleton.

This does not happen during normal summers when the temperature is a little high. Though the corals become paler, the relationship between the two is not affected as the food supply remains stable. But when the temperature increases drastically, like it is in the current decade, the problem arises. Corals are spitting out algae and the frequency and intensity of the heat waves are also rising.

The relationship between the coral and the algae is vital as it supplies 90% of coral’s energy through photosynthesis. This relationship is getting impaired. Bleached coral is nutritionally compromised and eventually dies. Record-breaking high temperatures have been observed in the Great Barrier Reef in 2016 from February to June, which was the cause of the worst coral bleaching event ever observed.

Species’ Imbalance

This shows how higher temperatures and an increased percentage of carbon in the oceans can act as a stressor for some species, whereas other species remain more or less unaffected. Because, in this case, corals are being affected, the corals themselves and the species dependent on them struggle to survive. Ocean warming and acidification are directly damaging to some other species, including fishes, seagrass, and even bacteria. This is changing the composition of species in the marine ecosystem.

The Bottom Line

Ocean acidification has increased drastically due to climate change and global warming. The increased carbon dioxide in the atmosphere is dissolving in the oceans to form carbonic acid, shifting the pH level of the ocean water. Effects of heat stress on oceans has reached unprecedented extremes. This is adversely affecting the marine ecosystem. The distribution of marine species is continually changing. In addition to this, sea ice and glaciers are melting at an accelerated pace, resulting in rising sea levels, ultimately aggravating human displacement.

Also read — Climate Change is happening NOW , Saving the Ocean and Will We Keep Driving Off The Climate Cliff?