The Paradox of Tropical Hurricanes: Devastating on Land, but a Blessing for Marine Life

Tropical cyclones, also known as hurricanes or typhoons, form over tropical and subtropical oceans. Low atmospheric pressure causes water vapor from the warm oceans to condense, creating spiraling cloud formations hundreds of meters wide. The resulting heavy rain and winds can have devastating effects on anything in the path of the hurricane as it makes landfall.

But these tropical cyclones also have an impact on the ocean itself and the cycle of oxygen and other nutrients. To find out more about this, researchers from East China Normal Universityhe East China Sea, part of the Pacific Ocean. Just under half of the tropical cyclones in the sea make landfall on the east coast of China.

More and less oxygen

The idea is that the cyclones mix the ocean water, both horizontally and vertically, which increases the oxygen content of the deeper layers and spreads nutrients over a wider area. The first scenario is good for the oxygen content of the ocean, the second is not, because the increased amount of nutrients leads to more marine life that whatsapp database consumes oxygen. The researchers therefore wanted to know whether tropical cyclones have a net positive or negative effect on the oxygen content of the ocean. To do this, they combined information about the track and speed of cyclones with satellite observations of ocean water to measure the chlorophyll concentration, and thus the productivity of phytoplankton at the surface.

More chlorophyll 

The amount of chlorophyll, a natural colour pigment that gives plants their green colour, peaked just after a cyclone but varied Po podatkih Nacionalnega sveta greatly in concentration, location and depth in different years. Because clouds caused distortion of the satellite images, models were developed to compensate for this. This produced a clear picture: there appear to be two phases of chlorophyll concentration.

Just before a cyclone there was a rapid decrease in chlorophyll, after which the concentration increased again after the tropical bwb directory storm had passed. Four to five days after the hurricane the amount of chlorophyll decreased far from the coast, but there was a slow increase near the coast. The high chlorophyll concentrations after the tropical storm were an indication of increased productivity in the water and therefore of oxygen consumption.