Ocean and Climate
The ocean covers 71% of our planet and it possesses a huge influence on our life that most of us don’t aware of. Let’s see how much of this we can explore here. “Ocean is the main contributor of oxygen” - yes you heard it right. Scientists estimate that 50 – 80% of earth’s oxygen is coming from the ocean specifically from phytoplankton, moving algae and some bacteria which can photosynthesize.
The ocean covers 71% of our planet and it possesses a huge influence on our life that most of us don’t aware of. Let’s see how much of this we can explore here. “Ocean is the main contributor of oxygen” - yes you heard it right. Scientists estimate that 50 – 80% of earth’s oxygen is coming from the ocean specifically from phytoplankton, moving algae and some bacteria which can photosynthesize. Not only that, but the ocean is also a huge sink for carbon. Guess what, for photosynthesis, these phytoplankton and bacteria need a huge amount of CO2 and thus they reduce the CO2 in the atmosphere. So, what we have learned here is that not only the plants that live on the land contribute to the carbon-oxygen cycle but also the plants living in the ocean. However, when we say not to harm the plants, we mostly focus on those which are above the land. This leads to a question, is the ocean safe for these species or is climate change not influencing the ocean. The answer is certainly yes. But, because we don’t give too much attention to the ocean when we talk about climate change or pollution, we don’t know too much about it. But you don’t have to worry about it. If you read this short passage, you will have some idea and next time when you see such news, you will give some attention to the oceans also.
FUN FACT
“Do you know that there is an architectural sound art object in Zadar, Croatia where the tides create sound like a piano when it hits the shore.”
Let's dive into the main topic....
Climate change is influencing the ocean. Ocean acidification intensifies in recent decades. Due to excessive absorption of CO2, more carbonic acid forms in the ocean. This makes the ocean more acidic. The average ph. of the ocean was 8.2 and now it has decreased to 8.1. Marine species from their shell and skeleton from carbonate. The excessive carbonic steals the carbonate and forms bicarbonate. This leads to the suffering of these marine species. Phytoplankton, zooplankton, and different algae are also getting affected by this which disrupts the marine food chain. The presence of the phytoplankton, zooplankton and the algae is limited to the depth up to which sunlight is available which is approx. 200 meters deep. The species that live below this zone solely depend on the oxygen that is dissolved in the ocean water. A recent study published in Nature mentioned that as the global temperature increases it causes more stratification in the upper oceans which restricts the mixing and thus the dissolved oxygen remains within the upper few meters where the mixing takes place. This stratification also limits the reach of sunlight which affects the reach of phytoplankton, zooplankton, and different algae. Combining these factors leads to a shortage of oxygen for marine species that live below a certain depth. Apart from atmospheric heatwaves, ocean heatwaves also exist. As the ocean warming increases so as the heatwaves. A study published in the Journal of Geophysical Research discussed the influence of these marine heatwaves on the Indian Summer Monsoon. Besides, when the marine heatwave hit a certain place, it gave very small time to adapt for the marine species.
These factors indirectly influence humans but there are some direct consequences of this relationship between the ocean and climate change. People who live in India are very fortunate to have the Indian Summer Monsoon which is one of the greatest weather systems on earth that transforms the barren land into lush green fields and supports agriculture over the subcontinent. However, the increase in a marine heatwave is influencing this monsoon. Besides this, the increase in global temperature melts the sea ice in the polar regions. Polar beers especially female polar bears depend on the sea ice to hunt. The loss of this sea ice threatens the existence of this ferocious predator. “Frozen Planet” documentary by BBC serves as a great platform to observe the dependency on the climate of different animals living in the poles and we can have an idea of how climate change can jeopardize their homeland. The increased sea level due to the sea ice melt and expansion of seawater (as the ocean water warms it expands in volume), can lead to the relocation of the people living in the coastal areas. In this prospect, India will be one of the most vulnerable countries, as the main megacities such as Chennai, Mumbai, and Kolkata will be long gone by the end of the next century if this continues, and actions are not being taken. Apart from these, there are some other sources from where the ocean can be affected such as intrusion of a large number of nutrients, oil spills from ships, etc.
Some actions to slow down climate change are taken but that is not enough to mitigate the warming. But, recently more countries are coming forward and leading the race to slow down this climate change. Let us keep the details of different countries’ actions on this for another article.
