Lack of oxygen (hypoxia) kills life in the sea

In the past I have already referred to the effect of global warming on the oceans. One of the signs of the significant changes happening to the oceans is the decrease in oxygen concentrations in the water, a decrease that harms the marine system. Damage to the food chain and life cycles

In the past I have already referred to the effect of global warming on the oceans. One of the signs of the significant changes happening to the oceans is the decrease in oxygen concentrations in the water, a decrease that harms the marine system. Damage to the food chain and life cycles.

Thousands of dead crabs appear on the shores of the oceans (following a drop in the concentration of oxygen in the water), joined by sea urchins, sea anemones and others that cover the bottom and form a food bed for bacteria, the bacteria produce toxins that kill more animals and thus a deadly cycle is created.

A state of low oxygen concentration exists (always) in the depths of the ocean, but recently areas where there is a lack of oxygen are expanding to the upper water column and to more continental shelves, due to global warming a warm layer of water is formed on the surface of the oceans, the warm water in the upper water column forms a "lid" that prevents natural circulation , circulating currents would "raise" water (poor in oxygen) from the depths, on the surface the water that comes in contact with the air dissolves oxygen and is enriched. Because of the "cap" created by the hot water, the cycle stops and areas are created where the lack of oxygen causes "dead areas".

A wind cycle that pushed water from the coast into the ocean caused deep water to be "pumped" to the surface, this is water poor in oxygen but rich in nutrients, nutrients that allow phytoplankton to bloom, when the phytoplankton sinks, rot is formed, a process in which oxygen is consumed, that is, oxygen comes from the water.

With the change of seasons, the direction of the winds that blow towards the coast reverses, a cyclical reversal that moderates the growth and sedimentation of the phytoplankton, it turns out that since 2002 the seasonal process has been violated, the winds are not strong enough to push and disperse the layer of water that was brought up from the depth, there is no dispersion therefore there is no absorption of oxygen. A violation that researchers attribute to global warming, a violation that (again) causes a lack of oxygen in the water.

The areas where the process takes place are: in the Pacific Ocean - off the coasts of the USA and off the coasts of Peru and Chile, in the Atlantic Ocean - from the coasts of Portugal to Namibia and DRAP, these are also the areas that were considered the richest in fishing, it was considered (in the past) because of the hypoxia in combination with Wild fisherman, the quantities of fish are dwindling.

Until today, the dead zones were attributed to nutrients/fertilizers that were transported to the sea from agricultural fields and sewers, today it turns out that in large areas where these dead zones were located, they were created due to worldwide climatic factors, that is, due to global warming.

The one who checked the issue is the oceanographer Gregory Johnson - National Oceanic and Atmospheric Administration in Seattle. According to him, there are places where in the last 25 years the oxygen level has dropped by 20%, a drop that he says predicts a drop of 35% in the coming years.

As the warming continues, the concentration of oxygen in the ocean water will decrease. In the meantime, we will observe a "dead zone" in the Baltic Sea, an area of ​​tens of kilometers covered with (toxic) algae. Algae "bloom" over limited areas is a natural phenomenon that occurs from time to time, but due to seepage and the flow of fertilizers/food coming from agricultural fields, the "bloom" expands and grows, creating expanding areas where the oxygen is "sucked up" by the algae, the oxygen concentration in the water drops to So that everyone who doesn't run away dies.

According to contemporary reports from Lebanon, most of the rivers that flow into the Mediterranean "collect" raw sewage and garbage on their way, so it is very likely that extensive dead areas will soon "bloom" in our immediate surroundings.

Continued warming will lead to lower and lower values ​​in the oxygen levels in the oceans, and if until now the dead zones have been attributed mainly to wastewater from agriculture and sewage, it turns out that more and more dead zones are created due to a (chronic) lack of oxygen in the water. The first victims are the "dwellers of the depths" who cannot escape fast enough, but the inhabitants of the central water column who manage to escape are also harmed, as the escape diverts the schools of fish from their migration routes and affects the arrival times at the spawning areas.

Species such as jellyfish and octopuses are not affected (or prefer) by low oxygen levels and indeed there is a population explosion of jellyfish (on the coast of Japan) and octopuses (on the coast of Mexico).

Another effect is the movement of oxygen-poor water towards the surface of the oceans. Dr. Codispoli Codispoti from UMCES Horn Point Laboratory explains that "the marine environment produces nitrous oxide (NOx), when there is less oxygen in the water, bacteria produce increasing amounts of NOx near the surface, in sunlight the phytoplankton activity increases, in the absence of oxygen A state of "denitrification" is created, a state in which nitrogen is found in the environment, combines with oxygen and is emitted into the atmosphere, a state in which the production of denitrification increases up to ten thousand times the production in a normal state."

"In a situation of normal oxygen concentration, about half of the world's carbon dioxide is created in the oceans, carbon dioxide is a greenhouse gas, in a situation of nitrogen the addition intensifies (from dead areas)" that is: if the cause of the lack of oxygen is warming, then the dead areas produce a greenhouse gas that increases the warming.

GHG also damages the ozone layer, isotope measurements have shown that: in the last 400 years there was a parallel between the GHG rise and the GHG rise in the atmosphere, human activity causes the GHG rise, human activity and warming causes dead zones that produce GHG that causes to warm up, and so the wheel turned.

In the past it became clear that: due to the increase in the level of DTP (and other greenhouse gases) in the atmosphere and their absorption by the oceans, the acidity of the water increases - an acidity that harms marine life. Excess acidity and lack of oxygen damage the marine environment and endanger its existence.

Now it turns out that there is another (negative) factor, hypoxia affects the marine environment and the food system in the water, now it is also clear that hypoxia "contributes" to damage to the ozone layer and warming. What will be the final result...?

In the past I referred to the possibility of "fertilizing" the oceans with iron in order to increase the development of phytoplankton that would absorb DTP from the atmosphere by assimilation, I also referred to the need to thoroughly examine the complex of effects of fertilizing with iron, now the picture is becoming clearer and a negative effect is evident, in the Proceedings of the National Academy of Science publishes a study that shows that the species that will multiply as a result of fertilization, the species that multiplies more as the temperature rises, will be Pseudonitzschia, (PSD), meaning that "PSD" has an advantage in warm water rich in iron. The "PSD" is a species of phytoplankton that produces toxic acid - omoic acid, a nerve poison that will spread up the food chain and cause the killing of fish, marine mammals and birds, since the higher up the food chain, the higher the concentration of the poison.

Since the concentration of iron in coastal waters is high, there are known cases in which the "psad" multiplied, until fishing was stopped in large areas, areas where there was an outbreak of the toxic "psad", in several cases people were poisoned and died after eating fish caught in the area.

The projects for fertilizing with iron are being pushed by private companies in an attempt to trade in DTP. Following the latest findings, there are companies that have stopped the project. There are those who have paused until further clarification, but there are also those who continue with the claim that: "For the good of the environment and to moderate global warming, the oceans should be fertilized with iron, a fertilization that will increase the growth of phytoplankton that will absorb/offset DTP from the atmosphere." It is important to know and understand that any intervention in the "chemistry of the oceans" has effects that are sometimes hidden and not always positive, therefore, before changing the world order, it is appropriate and correct to restore order, that is, to do everything to reduce emissions.