Broad-Scale Effects Of Hypoxia

The Chesapeake Bay is a 200-mile-long estuary extending from Norfolk, VA to Havre de grace Maryland. On average this bay contains about 68 trillion liters of water. This bay is the largest estuary in North America. It inhabits more than 3,000 species of plants, animals, and fish. “Since the early twentieth century, the Chesapeake Bay has experienced serious environmental degradation. Problems include large reductions in sea grass, reduced amounts of finfish and shellfish (especially oysters and crab), seasonal depletions in dissolved oxygen, and increases in sedimentation.” (Atkins & Anderson, 2003) These changes are brought on by pollution (Eutrophication and Toxic Contamination), development, deforestation, and agriculture. And according

Scientists and researchers began giving a large volume of effort and look into the extremely complex problems that face the Chesapeake Bay. When research for the improving and saving of the Bay’s overall health began it seemed very simple and there were only a couple of problems. The problems included nutrients from agricultural runoff; these nutrients were phosphorus and nitrogen. The combination of the nutrients in the Bay caused a large volume of algae that choked some of the marine life. While bringing in algae the nutrients also killed grasses on the seafloor. These seafloor bed grasses that once covered more than half of the Chesapeake Bay’s floor now only covered a tenth of their original area. Though the estuary was having problems it did not receive the terrible pollution from industries that many large rivers and lakes do in other urban areas (Brown, p. 397).

The CTDEP collected bottom- dwelling fish and invertebrates and compared the quantity of organisms and number of species with the levels of oxygen in the water. Both of these studies confirmed that severe effects occurred whenever levels of oxygen fell below 2.0 mg/l. Large reductions in the numbers and types of aquatic life present were noted. The lab experiments recorded reductions in both growth and increase in death.

Temperature had a direct effect on oxygen consumption of crayfish, Orconectes propinquus. Crayfish acclimated to warm temperature (20 to 25 C) had a mean mass of 8.25g +/- 1.05. Crayfish acclimated to cold temperature (3 to 5 C) had a mean mass of 10.61g +/- 0.77. Oxygen consumption rates of 30-60 minute treatments were used and there was no significant difference between the two different treatments (t=0.48, df=58, P=0.70). The data from 0-30 minutes were not used because the crayfish were disrupted by transportation and the data were not normally distributed. The Q10 value was 1.05, representing that there was full compensation for oxygen consumption for the crayfish at two different acclimated temperatures. The oxygen consumption of crayfish was not affected significantly by two different temperatures (Figure 1).

The increase of oxygen does not necessarily mean the fish will keep up with it. Too much oxygen can be harmful to the fish so you would need a certain amount per area of fish. A constant flow of oxygen going throughout the water habitat.

In this research paper I will talk about how a large decrease in the algae population in the Chesapeake Bay will cause problems for not just fish and other species but the people who fish and make a living off of it. A large decrease in algae population will have a domino effect on the food chain. Having a major decrease in algae will hurt how others species live and protect themselves.

This article presents the impact of low oxygen waters on Chesapeake Bay Zoo-plankton. Anoxia (oxygen deficiency) reduces the cope-pod abundances in Chesapeake's bottom waters, and disrupts the cope-pods inhabits towards the bottom and their migration to the surface. Also, cope-pods will have limited survival ability in low oxygen conditions in bottom waters. Results show the number of cope-pods surviving for 24 hours were significantly lower in water containing smaller milligrams of oxygen liter. Some will have a greater chance of survival because of their low metabolism that requires smaller oxygen. Low oxygen reduces the filtration rate of zoo-plankton and the filtration rate of the fresh water. Decreased filtration reduces metabolic rate in low-oxygen conditions, generally occur in the mesohaline part in summer. Low oxygen-levels may cut phyto-plankton and Cope pod's production. Lower oxygen concentration prevents hatching and the growth of eggs, which eggs could survive a few days if temperatures are cold and as the eggs sink to the bottom.

The Chesapeake Bay is the nation’s largest estuary with six major tributaries, the James, the Potomac, the Susquehanna, the Patuxent, the York, and the Rappahannock Rivers, feeding into the bay from various locations in Maryland, Virginia, Pennsylvania, and the District of Columbia (Chemical Contaminants in the Chesapeake Bay – Workshop Discussion 1). These areas depend on the Bay as both an environmental and an economic resource. Throughout the last 15 years the Chesapeake Bay has suffered from elevated levels of pollution. Nitrogen and phosphorous from wastewater treatment plants, farmland, air pollution, and development all lead to reduced water clarity and lowered oxygen levels, which harm fish, crabs, oysters and

Algae blooms have been an issue in the Chesapeake Bay, especially in the Baltimore Inner Harbor. Algae is a natural and critical part of the ecosystem, however in large doses it is harmful to the plants and organisms within the ecosystem. Algae blooms can block out sunlight and kill other plants in the water. Algae depends on various factors such as water, nutrients and carbon dioxide to grow. Eutrophication of the Inner Harbor has lead to algae blooms that have caused large fish kills in the past. When there is an over abundance of certain chemical nutrients eutrophication can occur. Runoff from land and farms is the main cause of excess nutrients into the water. The most common nutrients that are related to algae outbreaks are nitrate nitrogen and phosphate. In addition, a lack of dissolved oxygen can also be an indicator for the process of eutrophication and risk of an algae outbreak. A particular type of algae commonly found in Maryland is known as Prorocentrum minimum. Prorocentrum tends to cause “mahogany tides” causing water to be brown and have an odor. There has been a campaign launched by the Healthy Harbor

Some species might thrive in conditions that other struggle to survive. For example some predators might need more oxygen then a smaller prey. With less predators being around, there is a huge burst in prey, which can eat up all of the bacteria. When the bacteria all die, the prey can’t find any food and all die out. This causes a very unreliable food chain and can be dangerous to live in. In hypoxic zones what tends to happen is that marine life such as fish or shrimp die out quickly while the smaller organisms live. This causes whole species to die out leaving a dominance of gelatinous creatures such as jellyfish to thrive in.

The change in oxygen consumption averaged 445(mgO_2)/(hr∙Kg) when the fishes were exposed to ambient light and 377(mgO_2)/(hr∙Kg) when the fish were exposed to dark light. Across the trails, the average oxygen consumption as oxygen lost per hour per

Moreover, the professor indicates that the ecosystems may also caused other mammal animals decline. But the other mammal, like whales, didn't decrease. As a result, the ecosystem should not cause the sea cow need to face the food shortage. However, the author

Overfishing is defined as taking more fishes from the ocean compared to their replacement rates. Overfishing has a large impact on the ocean, as it leads to a collapse of the fish stocks, causing a chain reaction on the food webs and reducing the whole ecosystem’s resilience. Resilience is known as the maximum impact the ecosystem can withstand before it shifts into an alternate stable state. The loss of resilience of the marine environment makes it more vulnerable to other events (i.e ocean warming) such that the next sudden, extreme change would tip the ecosystem into a different state. Hysteresis occurs as different conditions are required for the ecosystem to shift back to its previous state.

The paper presents a review, analysis and a study on hypoxia faced by pilots at higher altitudes. The problems faced by pilots of commercial flights and the ways and means of dealing with them with the use of technology used in military planes will be the point of discussion and focus. The usage of technology that minimize the conditions of hypoxia at higher altitudes and reduction of its

Interestingly, hypoxia and anoxia have rarely been documented in the East China Sea (ECS) which is one of the largest continental shelves in the world (e.g., Li et al., 2002). Historically, the ECS has been one of the world’s major fishing grounds, especially within