hytoplankton are microscopic algae found floating and drifting in the upper layer of the oceans. They perform the very essential task of preparing food for those organisms which don’t have the means to do it by themselves. Phytoplankton achieve this by following the process of photosynthesis, in which they utilize sunlight and carbon di oxide to create food for themselves and for other marine organisms as well.
Ever wondered what the consequences will be if there were no phytoplankton left on earth!
If phytoplankton concentration starts declining there won’t be enough food left for the marine ecosystem organisms such as zooplankton, fishes, whales and even seabirds. As a result their populations will also shrink.
This will also affect the fish farms all over the world, which require phytoplankton in order to feed their fishes.
One more reason why phytoplankton decline is an issue of global concern is that they influence the earth’s climate to a great extent. By consuming the carbon dioxide during photosynthesis, they get rid of the excess CO 2 from the atmosphere, and thus help in controlling global warming. There are phytoplankton species which are known to influence cloud formation by creating cloud condensation nuclei where rain droplets may condense. Some of them are known to reflect and some to absorb solar radiation, creating stability [WU1] in the earth’s overall temperature.
Something for which phytoplankton must be considered very important is that they produce a major part of the oxygen which we breathe. Prochlorococcus, a phytoplankton, is estimated to provide oxygen for one amongst the five breaths we take. It is this fact which makes them so important for all the living creatures on earth.
There has been a global decline in the concentration of phytoplankton in the past century. The rate of decline is estimated to be approximately 40% since 1950. This trend has been observed in 8 large oceanic regions, and is greater in polar and tropical regions.
What is the cause of this decline?
Rising sea surface temperature makes the oceans stratified in stable layers of water of different temperatures. This means there will be less intermixing of the lower, cooler level oceanic water with the warmer surface water. The lower waters contain nutrients which the phytoplankton need to grow, so the less they mix with the surface water the less food phytoplankton will get, and as a result their concentration will decline.
Global phytoplankton decline is a serious problem; their existence is not only important for ocean ecosystems, but also for earth’s climate, fish farms and for absolutely everything which needs oxygen to survive.