Marine Bio chapter 18

What is a major cause of habitat modification and destruction near shorelines?

Unplanned or poorly planned development due to the greater number of humans nearby.

What percentage of coral reefs have already been lost or are at risk?

Approximately 1/4th of all coral reefs.

What are the primary threats to coral reefs?

Sewage, sedimentation, rising temperatures, and collection for the aquarium trade.

What percentage of reef-building corals currently face extinction?

About 40%.

What is a significant problem caused by trawling?

Trawl nets drag along the bottom, causing resuspension of sediments that can kill suspension feeders.

What is pollution in the context of the marine environment?

The human introduction of substances that reduce the quality of the environment.

Name three sources of pollution affecting marine environments.

Fertilizers, sewage, and oil.

How do fertilizers contribute to marine pollution?

They wash into coastal waters, causing phytoplankton blooms that lead to eutrophication.

What occurs after phytoplankton die in the marine environment?

Decomposing bacteria consume oxygen, potentially leading to anoxic conditions.

What are the effects of oil pollution on marine organisms?

It can affect reproduction, growth, and behavior, and can coat feathers or fur, leading to death.

What are persistent toxic substances, and give examples.

Substances like chlorinated hydrocarbons and heavy metals that accumulate in organisms and can cause biomagnification.

What is the status of species that are threatened?

Their numbers are low, and they are in danger of becoming endangered.

What is the definition of an endangered species?

A species that is in immediate danger of extinction.

What is an example of a species that became extinct due to human actions?

Steller's sea cow, exterminated by overfishing.

Name two marine species currently imperiled due to human activities.

Whales and sea turtles.

What are some conservation methods used to protect marine organisms?

Efforts include sustainable development, fisheries management, marine protected areas, and habitat restoration.

What is the purpose of artificial reefs in marine conservation?

To provide habitats for marine organisms and enhance biodiversity.

What is the impact of thermal pollution on marine environments?

It can disrupt the natural temperature balance and affect marine life.

What is bioacoustics in the context of marine larvae?

Marine larvae use sound to guide their swimming to suitable environments.

What is eutrophication, and how is it caused?

A process where nutrient influx leads to excessive phytoplankton growth, often caused by fertilizers.

What is the impact of solid wastes on the marine environment?

They contribute to pollution and can harm marine life.

What is the role of noise pollution in marine environments?

It can interfere with the communication and navigation of marine organisms.

What are saline brines, and how do they affect marine environments?

Byproducts from desalination plants that can alter salinity levels and impact marine life.