What is the term for the accumulation of dead planktonic organisms that have sunk through the water column?

What problem is faced by organisms that live in freshwater?

The following diagrams are longitudinal cross-sections of a sponge (Grantia sp.). Which diagram correctly represents the flow of water through the sponge? A B MA

A group of students wanted to learn how the concentration of copper in water affects the survival of tiny aquatic plankton called Daphnia. The students made four different copper solutions: 0% copper, 0.5% copper, 1% copper, and 2% copper. They poured 200mL of each solution into separate beakers and added 10 Daphnia to each beaker. After 5 days, the students counted how many Daphnia were still alive in each beaker. What is the control treatment in this study?

What are some very productive marine environments, and why are they so productive?

What lesson about water was learned from Hurricane Katrina?

What is the source of nutrients for animals living in the deep-sea habitat?

What is the fundamental difference between protozoans and algae?

What two problems facing marine species?

What do you think would happen to both the catfish and the algae if another fish that eats algae were added to the pools? What would happen initially?  And over time?