freshwater ecosystem
91Ecology — For other uses, see Ecology (disambiguation). Ecology …
92Algal bloom — Algal blooms can present problems for ecosystems and human society An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system. Algal blooms may occur in freshwater as well as marine… …
93River delta — Nile River delta, as seen from Earth orbit. The Nile is an example of a wave dominated delta that has the classic Greek delta (Δ) shape after which river deltas were named. A delta is a landform that is formed at the mouth of a river where that… …
94Zebra mussel — Live zebra mussels underwater with shells open, animals respiring, siphons visible. Scientific classification Kingdom …
95Demersal fish — Bluespotted ribbontail ray resting on the seafloor Demersal fish live on or near the bottom of the sea or lakes.[1] They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks …
96Hypoxia (environmental) — Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen (DO; molecular oxygen dissolved in the water) becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms… …
97Pelagic fish — A school of large pelagic predator fish (giant trevally) sizing up a school of small pelagic prey fish (anchovies) Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or… …
98Deep sea fish — Humpback anglerfish Deep sea fish is a term for any fish that lives below the photic zone of the ocean. The lanternfish is, by far, the most common deep sea fish. Other deep sea fish include the flashlight fish, cookiecutter shark, bristlemouths …
99Danube Delta — Danube Delta * UNESCO World Heritage Site Country Romania …
100Seabird — This article is about the animal. For the alternative rock band of the same name, see Seabird (band). The Sooty Tern is highly aerial and marine and will spend months flying at sea, returning to land only for breeding.[1] Seabirds (also known as… …
