Aquatic Diversity Flashcards
Ocean acidification
Not explicitly defined, but it’s typically the decrease in pH levels of the ocean due to increased carbon dioxide absorption, impacting marine life.
Total allowable catch
The maximum quantity of a particular fish species that can be caught in a specific area during a specific time period to prevent overfishing.
Fishing Down the Food Web:
A practice where, due to the depletion of top predators, fisheries target species lower in the food web.
Driftnetting:
A fishing technique using large nets that drift with the currents to catch fish, often resulting in significant bycatch.
Longlining:
A fishing technique using a long line with baited hooks spaced at intervals, which can also catch non-target species.
Bottom Trawling: .
A method of fishing that involves dragging heavy nets across the sea floor, often damaging habitats and resulting in high bycatch
Bycatch:
The unintentional capture of non-target species such as dolphins, turtles, and seabirds during fishing.
Overexploited Fishery:
A fishery where fish stocks are harvested at unsustainable levels, threatening their existence.
Depleted Fishery:
A fishery with significantly reduced fish stocks due to overfishing.
Fully Exploited Fishery:
A fishery operating at its maximum sustainable capacity, with no room for expansion.
Moderately Exploited Fishery:
A fishery with potential for expansion in fish catch without threatening the species.
Maximum Sustainable Yield:
The largest long-term average catch that can be taken from a stock under prevailing environmental and fishery conditions.
Marine Reserve:
A protected area where fishing and other potentially harmful activities are restricted to preserve marine ecosystems.
describe threats to aquatic biomes/ecosystems.
The document you provided outlines several threats to aquatic biomes and ecosystems:
Habitat Alteration or Loss: This includes the creation of “dead zones” in areas like the Gulf of Mexico due to hypereutrophic conditions from excess nutrients. These conditions lead to phytoplankton blooms and anoxia, which prevent the survival of many animal species while not affecting phytoplankton or bacteria. Habitat loss is often related to pollution and can be exacerbated by climate change due to atmospheric pollution that originates on land.
Overharvesting: Overfishing is a major threat to many marine animals. The document cites the example of the cod fishery, which was heavily exploited by European fishers since the 1500s, leading to a significant decline in cod populations. Overharvesting can result from advancements in fishing technology, such as massive trawlers, and has led to the overexploitation of fisheries.
Climate Change and Ocean Acidification: Rising ocean temperatures, often a result of climate change and greenhouse gas emissions (like CO2 and CH4), stress marine life, particularly coral reefs. This stress can lead to coral bleaching and zooxanthellae expulsion, negatively affecting coral health. Ocean acidification further compounds these issues, impacting calcification processes in marine organisms.
Bycatch from Fishing Techniques: Techniques like driftnetting, longlining, and bottom-trawling often result in the accidental capture of non-target animals, such as seals, dolphins, sea-birds, and various non-marketable fish, crustaceans, and shellfish. This bycatch is a significant threat to marine biodiversity and is exacerbated by improved fishing technology like sonar and satellite navigation, which increase harvesting efficiency but can mask declining fish stocks.
These threats highlight the need for sustainable fishing practices, habitat conservation, and addressing broader environmental issues such as climate change and pollution to protect aquatic ecosystems.
Describe the two effects of atmospheric pollution on our oceans that were discussed. Specifically, a) explain how carbon dioxide leads to coral bleaching; and b) explain how carbon dioxide interferes with the formation of shells and corals. use the document above to answer the following question
a) Carbon Dioxide Leading to Coral Bleaching: Increased atmospheric pollution, including elevated levels of carbon dioxide, contributes to global warming and climate change. This, in turn, leads to a rise in ocean temperatures. Coral reefs are particularly sensitive to changes in temperature. When corals are stressed by temperature changes (either too high or too low), overexposure to sunlight, pollution, or extreme low tides, they expel the zooxanthellae – photosynthetic microorganisms that live in a symbiotic relationship with corals. This expulsion results in coral bleaching, where corals lose their color and their major source of food, making them more susceptible to disease and death. The health of corals is further compromised by ocean acidification, which is also a result of increased carbon dioxide in the atmosphere.
b) Carbon Dioxide Interfering with Shell and Coral Formation: The document also touches on the broader impact of ocean acidification, which is directly linked to increased levels of carbon dioxide. When CO2 dissolves in seawater, it forms carbonic acid, which lowers the ocean’s pH. This acidification process can significantly impact calcifying organisms, including shellfish and corals, by reducing the availability of carbonate ions, which are crucial for shell and coral formation. As a result, these organisms have a harder time producing their calcium carbonate structures, leading to weaker shells and coral skeletons. This not only affects the individual organisms but also the broader marine ecosystems that depend on them.
