The Changing Sea (Essay Sample)

The Changing Sea
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Introduction
It is a popular notion that a large percentage (more than 50%) of the ocean life has not yet been discovered by humans. Although humans have not yet come to grasp the full extent of oceanic life, much study has been done on the seven seas—ecologically. The study of the seas and the profound evolution they have undergone shows various changes occurring in this different realm. One of these notable changes is the rapid increase of dead zones in the oceans. These areas of minimum oxygen are observed to have significant effects on aquatic life. This paper explores the causes of the dead zones and the particular effects and changes it impacts. It follows a research of the information provided on the dead zones and the potential pitfalls in the evidence. A close scrutiny of the evidence will help in determining their reliability in our perception of how the ocean works.
A dead zone is part of the ocean that essentially lacks enough oxygen to support any aquatic life. According to a report by the National Science Foundation (NSF), dead zones form in instances where microscopic plants, specifically phytoplankton, are sufficiently fertilized by nutrients occurring in excess, these are for example, fertilizers and sewage (NSF, 2010). These wastes are primarily the high nutrient waste products generated by human activities near oceans and dumped into the ocean through river conduits, or in rare cases, instances where excess fertilizer used in the farms finds its way into streams that lead the water into oceans. The National Oceanic and Atmospheric Administration (NOAA) puts it that, the excessive nutrient pollutions that humans cause lead to the depletion of oxygen in both deep and near deep levels of the ocean (NOAA, 2012).
Although dead zones are observed to occur naturally in some instances, most of the instances, as mentioned above, can be accounted for by human activity. However, some natural causes include coastal upwelling and various changes in the wind and water cycles patterns (Rosenberg, 2008). The dead zones caused by natural causes are seen to be significantly milder than those by human activities. Some of the impacts on aquatic life are total life annihilation and reduced volume of water in the affected regions (Pickard and Emery, 1982). The annihilation process starts when the waste is deposited; the waste forms a platform for the formation of algae whose growth is also facilitated by the deposited nutrients. The normal working of the ocean is disrupted when the algae (phytoplankton) suppresses the life sustaining planktons leading to an extinction of life sustaining nutrients and in the event, a gradual migration and/or death of fish in the area. Some of the dead zones are reported to cover over seventy-two thousand square kilometers of ocean (NSF, 2010).
Evidence of dead zone prevalence
A most recent report on dead zones is one published by the NOAA in the year 2010. Prince, a fisheries biologist, leads the team in presenting the report on the growing rate of hypoxic zones (low oxygen zones). The report essentially focuses on the effect of dead zone to fishing activities, both commercial fishing and leisure. In addition, it follows that the evidence acquired from the explored expanding dead zones has led to either a reduction of important fish in the sea like marlins or a migration of the important fish to areas that make them most vulnerable to fishing and reducing their overall population.
In order to show the significance and evidence of the report, it is explained that blue marlins and most of other billfish are high energy fish that require significantly large quantities of dissolved oxygen. In essence, by comparing the migration of the blue marlins and the location of low-oxygen areas, the scientists are able to show that blue marlins prefer to indulge deeper in instances where dissolved oxygen levels are higher in the water and in turn move to shallower surfaces when low oxygen encroaches their preferred habitats in deeper waters.
According to an article on the spread of dead zones by Rosenberg and Diaz, they put it in a portion of their introduction that: dead zones in the coastal oceans have experienced an exponential expansion since the 1960s and have from then on, had serious consequences on the normal functioning of the ecosystem. The formation of dead zones has been accelerated significantly by the increase in raw production and as a result, a worldwide coastal eutrophication fueled by riverine runoff of fertilizers and the burning of fossil fuels (Diaz and Rosenberg, 2008).The evidence given by the article reinforces on the causes of the dead zones. The researchers add that, enhanced production along the coastlines results in a concentration of particulate organic matter, as earlier mentioned, this in turn encourages microbial activity and the consumption of dissolved oxygen in bottom waters. The report also gives statistics on the dead zone prevalence citing that dead zones have been reported from more than 400 systems and cover more than 245, 000 square kilometers of ocean water, the article adds that this is probably the sole stress on the marine eco-system. The article also has intricate figures that show evidence of dead zones existing mostly in the northern hemisphere—close to more than 40% (Diaz and Rosenberg, 2008).
Conclusion
The above articles and reports by the different organization give a significant perception of the scope of the changing sea. Evidence from most of the reports shows that most of the dead zones were not discovered until the 1960’s. This period is seen to be one of the most industrialized periods in history. The industrial advancements made before the first discovery of the dead zones can be owed to their conception. Oceanography performed in mod...