Question

QUESTIONS ON MARINE BIOLOGY- WILL GIVE A MEDAL!

Why are estuaries important? Give eight reasons.
Why must organisms in an estuary have special adaptations? Give three examples.
How do estuaries compare to other areas in terms of production?
What is the main source of "production" in an estuary?
What is detritus and why is it important? Explain.

I can come up with some reasons but this topic is confusing! Please help!

Answer 1

question 1: n addition to providing economic, cultural and ecological benefits to communities, estuaries deliver invaluable ecosystem services. Ecosystem services are fundamental life-support processes upon which all organisms depend (Daily et al., 1997). Two ecosystem services that estuaries provide are water filtration and habitat protection.

Habitats associated with estuaries, such as salt marshes and mangrove forests, act like enormous filters. As water flows through a salt marsh, marsh grasses and peat (a spongy matrix of live roots, decomposing organic material, and soil) filter pollutants such as herbicides, pesticides, and heavy metals out of the water, as well as excess sediments and nutrients (USEPA, 1993).

One reason that estuaries are such productive ecosystems is that the water filtering through them brings in nutrients from the surrounding watershed. A watershed, or drainage basin, is the entire land area that drains into a particular body of water, like a lake, river or estuary. In addition to nutrients, that same water often brings with it all of the pollutants that were applied to the lands in the watershed. For this reason, estuaries are some of the most fertile ecosystems on Earth, yet they may also be some of the most polluted.

Estuaries and their surrounding wetlands are also buffer zones. They stabilize shorelines and protect coastal areas, inland habitats and human communities from floods and storm surges from hurricanes. When flooding does occur, estuaries often act like huge sponges, soaking up the excess water. Estuarine habitats also protect streams, river channels and coastal shores from excessive erosion caused by wind, water and ice.

Unlike economic services, ecosystem services are difficult to put a value on, but we cannot do without them, and thus, they are essentially priceless.

Answer 2

question 2: Mangrove trees and blue crabs are some of the estuarine species that have adapted to unique environmental conditions. In almost all estuaries the salinity of the water changes constantly over the tidal cycle. To survive in these conditions, plants and animals living in estuaries must be able to respond quickly to drastic changes in salinity.

Plants and animals that can tolerate only slight changes in salinity are called stenohaline (Sumich, 1996). These organisms usually live in either freshwater or saltwater environments. Most stenohaline organisms cannot tolerate the rapid changes in salinity that occur during each tidal cycle in an estuary.

Plants and animals that can tolerate a wide range of salinities are called euryhaline. These are the plants and animals most often found in the brackish waters of estuaries. There are far fewer euryhaline than stenohaline organisms because it requires a lot of energy to adapt to constantly changing salinities. Organisms that can do this are rare and special. Some organisms have evolved special physical structures to cope with changing salinity. The smooth cordgrass (Spartina alterniflora) found in salt marshes, for example, has special filters on its roots to remove salts from the water it absorbs. This plant also expels excess salt through its leaves.

mangrove trees

Oysters can live in the brackish waters of estuaries by adapting their behavior to the constantly changing environment. Click on image for more details and a larger view. (Photo: Apalachicola NERRS site)


Unlike plants, which typically live their whole lives rooted to one spot, many animals that live in estuaries must change their behavior according to the surrounding waters' salinity in order to survive. Oysters and blue crabs are good examples of animals that do this.

Answer 3

question 3: There is no productivity in an estuary.

Estuaries are the most productive of all marine ecosystems.

Estuaries are productive, but far less than other marine ecosystems.

Estuaries are the least productive of all marine ecosystems

Answer 4

question 4: Ditritus

Answer 5

question 5: Detritus is decomposing matter from dead organisms, old plants, etc. It is vital to most ecosystems because certain organisms use it for food, and it replaces lost nutrients from the ecosystem, nutrients such as nitrogen and phosphorus.

Answer 6

Thank you so much

Answer 7

any time @foreverjennnicole