Question

1. which ecosystem is most characteristic for high nutrient retention, peat or organic - rich soils, and water filtration services?

a. open ocean
b. coastal reef
c. wetland
d. fast - flowing river

1. coastal marine productivity is often high where:

a. thermoclines are strongest and prevent mixing
b. upwelling brings cold, nutrient - rich water to the surface
c. salinity is near zero
d. substrate is exclusively rocky

Explanation:

• Question 3: Wetlands are known for their ability to retain nutrients, have peat or organic - rich soils, and provide water filtration services. Open oceans have low nutrient retention in the surface layers (most nutrients are in the deep), coastal reefs are more about biodiversity and wave protection rather than the described soil and filtration features, and fast - flowing rivers tend to carry nutrients away rather than retain them.
• Question 4: Upwelling brings cold, nutrient - rich water to the surface. In coastal areas, when upwelling occurs, it supplies the necessary nutrients (like nitrates, phosphates) for primary producers (phytoplankton) to thrive, increasing productivity. Strong thermoclines (which prevent mixing) would limit the supply of nutrients to the surface, salinity near zero is not a characteristic of productive coastal marine areas (they are still marine, so salinity is significant), and a substrate that is exclusively rocky does not directly relate to high productivity (though some organisms may attach to rocks, it's the nutrient supply that is more crucial for overall productivity).

Answer:

1. C. Wetland
2. B. Upwelling brings cold, nutrient - rich water to the surface