The dead zone is littered with the carcasses of dead sea animals. There are 405 dead zones reported world-wide. Natural and Human Impact Dead zones can be caused by both natural and human impact on the environment. High levels of chemical nutrients (nitrogen and phosphorus) cause algae blooms to flourish. After the algae accumulate, it dies, decomposes and depletes the oxygen in the ocean creating a dead zone.
Factories create equipment that destroys species in the ocean. When these species are destroyed the food chain is ruined and this threatens the ocean. Over Fishing is also harming the ocean. Entire populations of fish are being killed. Over fishing occurs when there are more fish caught than fish in the ocean to sustain fish stock.
The production of these toxic-filled substances continues to lead the human race on a path of natural destruction; with thousands of animal sea-life dying annually from plastic consumption. It's time we wake up to the fact that our oceans are in need of critical help. How did the plastic get into our oceans to begin with? The oceans are enormous but they are not infinite. Today, as in the past, oceans are being treated as giant disposal areas for all types of refuse (plastics, tins, bottles etc.)
Elevated pH can in turn ‘blind' organisms that rely on perception of dissolved chemical cues for their survival by impairing their chemosensory abilities (Figure 3) (Turner & Chislock 2010). When these dense algal blooms eventually die, microbial decomposition severely depletes dissolved oxygen, creating a hypoxic or anoxic ‘dead zone' lacking sufficient oxygen to support most organisms. Dead zones are found in many freshwater lakes including the Laurentian Great Lakes (e.g., central basin of Lake Erie; Arend et al. 2011) during the summer. Furthermore, such hypoxic events are particularly common in marine coastal environments surrounding large, nutrient-rich rivers (e.g., Mississippi River and the Gulf of Mexico; Susquehanna River and the Chesapeake Bay) and have been shown to affect more than 245,000 square kilometers in over 400 near-shore systems (Diaz & Rosenberg 2008).
The ocean dwellers are virtually helpless, and they will ultimately have to suffer the consequences that have been created mainly by humans. Over the past few years there has been a significant change in marine life. Coral reefs are becoming endangered due to high carbon dioxide levels and effects of warming. Large predators, small fish, and other organisms make their homes in coral reefs. A process called mass bleaching has also become a danger to coral reefs.
Environmental Hazards a. In the St. Lawrence River, lots of industry has resulted in high levels of toxic chemical such as polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) and heavy metals. b. Because these toxins affect not only one specie but also all of species that are interconnected by food chain. c. These pollution decline beluga’s immune system, get disease easily that linked to low birth rates of belugas which have lived in the St. Lawrence River.
To purify polluted water we may use different type of methods according to the pollutants entered in the water. Chemical disinfection of water is one of the most important methods in the process of purifying water; this method can kill lots of pathogens that exist in the polluted water by killing them. http://www.informaction.org/images/graph_ocean-pollutants.jpg Fig 1 Water is made up of two hydrogen’s and one oxygen. Most part of the earth is water that means three fourth of the earth is made up of water but the problem is most of it is not suitable for drinking. https://qed.princeton.edu/getfile.php?f=Water_Pollution_since_the_1960s.jpg Fig 2 water pollution world wide In 1854 the British scientist John Snow discovered that cholera disease was caused by the contamination of water, he also showed that chlorine can be used to disinfect contaminated water to prevent such kind of diseases.
What has happened to destroy so many reefs? Human population has become very large, and earth is warming. There are two different ways in which humans have contributed to the degradation of the Earth's coral reefs, indirectly and directly. Indirectly, we have destroyed their environment. The large population centres near coasts has led to silting of reefs, pollution by nutrients that lead to algal growth that smothers the coral, and overfishing that has led to increase in number of predators that eat corals.
October 9, 2012 “Great Pacific Garbage Patch” Today’s society is facing a big problem with pollution, probably when we talk about pollution you just think about air pollution. But Captain. Charles Moore of the Algalita Marine Research Foundation discovered the Great Pacific Garbage Patch. The Pacific Garbage is an endless floating waste of plastic trash, that is killing many sea animals and underwater vegetation, but Captain Moore mission is to draw attention to the growing, and choking problem of plastic debris in our seas. The Great Pacific Patch stretch for hundreds of miles across the Pacific Ocean, basically the North part is forming a floating junkyard.
Humans have been known for destroying coral reefs through unlawful fishing habits. Cyanide fishing has been classified as a destructive fishing practice, yet is still being used in our oceans today. The destruction of coral reefs is greatly due to the fact that many people are unaware of a number of things. Such as the what coral reefs are, the key role they play, what cyanide fishing really is as well as the negative effects the fishing will cause. Occupying less than one percent of the ocean floor, coral reefs are home to over 25% of all marine life.