After the algae accumulate, it dies, decomposes and depletes the oxygen in the ocean creating a dead zone. Natural elements of climate, weather and change in wind circulation also cause changes in algae growth. In the spring months increased rain, water flow and sunshine increase this algae growth. In the fall tropical storms and hurricanes break up the algae and the cycle repeats again. The largest human cause of dead zones is nutrient run off from abundant use of fertilizers, animal waste and sewage.
Asian Carp Invasion David Long University of New England The United States Environmental Protection Agency recently began fighting an invasive fish called the Asian Carp. These fish are causing problems around the world destroying fishing industries and eco systems. There are four species of the fish, of the two the bighead and the silver carp are the closest to invading the great lakes. The bighead carp can grow up to one hundred pounds and the silver carp are known for jumping out of the water when frightened and scaring boaters. These fish pose a significant threat to the great lakes due to their large size and feeding habits.
At one time, as many as 500 species of cichlids existed making Lake Victoria one of the most diverse lakes in the world. However, the number of cichlid species has now plummeted to just 200, mainly due to the Nile Perch. A side effect of the loss of cichlid species is that a significant number of them feed on detritus. With declining numbers of cichlids to feed on detritus, more unconsumed
Many different kinds of fish live in the reefs as their haven for feeding, reproduction, and safety from predators. Without an ecosystem to live in, these fish species will become extinct. Ten percent of the world's reefs have been completely destroyed. Coral reef destruction is the worst, over 70% have been destroyed and only 5% can be said to be in good condition. What has happened to destroy so many reefs?
2. Do background research – Utilizing at least one scholarly source, describe how variations in dissolved oxygen content in a body of water can affect fish populations. Answer = “Oxygen depletions are the most common cause of fish kills in ponds. (Aquaplant, 2014).” Based on my observation of the chart and what I read, the higher the dissolved oxygen levels the number of fish drops. Dissolved oxygen levels can also cause fish to suffocate and be more susceptible to diseases.
In other cases, the algae blooms from eutrophication turn out to be incredibly toxic species (National Academy of Sciences 696). One particularly nasty algae is Pfiesteria piscicida which emits toxins that break down the skin of fish, causing bleeding and sores and ending in mass fish death (Howarth 39). In August 2005, a dairy farm in Western New York experienced a manure lagoon collapse, which resulted in 3 million gallons of manure funneling into the nearby Black River, where it killed as many as 250,000 fish, brought all recreation to a halt, and forced the city of
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).
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.
• Aquatic ecosystems: Acid rain makes water bodies, such as streams, rivers and lakes, acidic. At a pH below 5, fish eggs are unable to hatch and a lower pH can kill adult fish as well. This was seen in Canada, as the sport fish population in acidified lakes showed reproductive failure, skeletal deformities and increased mortality rate due to acid rain. In southern Norway during the 1970’s fish were killed in over 20% of the lakes as a result of acid
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.)