With increasing polluting human activities, the pure environment is getting contaminated and becoming unsafe for sustaining life! Environmental pollution is no new topic for us but at front of such a vast world, we are unknowingly killing our focus from the most important part of ecosystem-phytoplankton, a single-celled grass of the sea (With life span rarely more than a few days) that nourishes and sustains the entire southern ocean’s food chain.
Phytoplankton lives in the euphotic zone, the uppermost layer of the water column, so that chlorophyll present in it can capture sufficient sunlight energy to assimilate carbon and synthesize organic compounds in photosynthesis. Thus releasing oxygen, allowing the water to absorb atmospheric carbon dioxide regulating temperature, maintaining “global carbon cycle”. These small changes in the growth of phytoplankton may affect atmospheric carbon dioxide concentrations, changing global surface temperatures; such important is phytoplankton.
Phytoplankton growth depends on various factors. When these conditions are right, bloom (phenomenon of explosive growth of phytoplankton) occurs. To support the estuarine food web, phytoplankton must be produced in great quantities else the food chain breaks and animals suffer. But its growth today is interfered by:1) Pollution ,2)global warming and 3) ozone layer depletion due to which UV radiation cell damage both plant (phytoplankton) and animal (zooplankton) species at the base of the ocean food chain due to lack of their protective outer layers.
But the ozone layer (highly reactive molecule made of three oxygen atoms) provides shield from the harmful ultraviolet radiation emitted by the sun. It is constantly being formed and broken down in the region called the stratosphere, 10 to 50 kilometers above Earth. But even this savior layer is getting damaged. Chlorine obtained from break down of ChloroFluoroCarbons (CFCs) when exposed to ultraviolet rays upon reaching the upper atmosphere reacts with the oxygen atoms in ozone resulting in its depletion. Thus, planktons have reached to their maximum tolerance of UV radiation. The stratospheric ozone layer over the Antarctic is thinning resulting in ozone hole. Since hardly any direct sunlight reaches the continent for most of the year, the Antarctic organisms have a low tolerance for UV radiation. But in springtime, UV radiations penetrate the atmosphere with a higher intensity affecting Antarctic organisms reducing the plankton population.
Any further depletion in ozone layer will affect the activities and alter growth of phytoplankton, which in turn will affect the lives of all the marine animals and birds of the region and the global carbon cycle. But if we determine to ensure and act to stop further depletion of ozone layer by minimizing use of cfcs, inhabiting anti-pollution activities, promoting afforestation, then we can all together save our ecosystem and the very being of our beautiful planet.
