Algae is a heterotroph and consumes more oxygen than it produces.

Decreased light penetration limits photosynthesis below the surface.

Bacteria consume oxygen as they decompose dead algae and other organisms.

Decomposes that would have produced oxygen are outcompeted by algae.

bacteria use it as they decompose organic material

algae uses it during photosynthesis

it reacts with hydrogen to form H2O (water)

fish use it up as they consume algae

increased growth of algae

decreased biodiversity

runoff from fertilizer

chemical reactions with pesticides and fertilizers

Nutrients would be used up by the fish and plants, keeping the estuary in balance.

Algal blooms would lower dissolved oxygen levels, causing fish to suffocate.

Algal blooms would decrease, leaving few food resources for fish.

Nutrients would sink to the bottom, increasing soil deposition.

algae bloom

lake turnover

photosynthesis

respiration

rain water washes lawn and agricultural fertilizers into the ecosystem

Scientists are adding fertilizer to the ecosystem

Nitrogen fixing bacteria are creating an excess of organic nitrogen compounds

algae are causing denitrification in the water

A

B

C

I

H

They are critical plant nutrients.

They kill off competition.

Because algae grow faster than decomposers.

Nitrates and phosphates are density independent limiting factors.

a fish

oxygen deficiency

rainfall

carbon dioxide deficiency

True

False