Aquatic Biomes
Introduced| English | Meaning |
|---|---|
| aquatic/əˈkwætɪk/ | aquatic |
| salinity/seɪˈlɪnɪti/ | The concentration of dissolved salts in water or soil water. |
| freshwater/ˈfreʃwɔːtə/ | freshwater |
| marine/məˈriːn/ | marine |
| estuary/ˈestjuːəri/ | The brackish mix where a river meets the sea. |
The water worlds
- Most of Earth's surface is water, and it teems with life.
- Aquatic biomes range from a tiny pond to the vast open ocean.
- What separates them is not temperature but salt.
- The amount of salt decides which creatures can live there.
Salinity divides the waters
- Aquatic 水生的 biomes are sorted mainly by their salinity 盐度 — how salty the water is.
- Freshwater 淡水 biomes, like lakes and rivers, have very little salt.
- Marine 海洋的 biomes, like the ocean and reefs, are salty.
- Most organisms are adapted to one or the other, not both.
A coral reef: warm, sunlit, shallow water makes it one of the most productive and biodiverse of all biomes
Aquatic biomes are mainly divided by their salinity, which means…
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Salinity is the amount of dissolved salt; it separates freshwater from marine biomes.
Where waters mix
- An estuary 河口 is where a river meets the sea.
- Its water is brackish — a mix of fresh and salt.
- Estuaries are among the richest, most productive places on Earth.
- They act as nurseries for fish and feeding grounds for birds.
Which is a marine biome?
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A coral reef is marine (salt water); lakes, rivers and ponds are freshwater.
The brackish place where a river meets the sea is called an ____.
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An estuary is where fresh and salt water mix; it is very rich in life.
Sunlight and life
- Sunlight only reaches the shallow, upper layer of water.
- Producers like algae need that light to photosynthesise.
- So most aquatic life is packed into the sunlit surface waters.
- The deep, dark ocean holds far fewer living things.
Freshwater, marine, or in-between?
Sort each aquatic biome by its salinity - fresh, salty, or the brackish mix where they meet.
Most aquatic life is found in shallow, sunlit water where photosynthesis can happen.
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Sunlight only reaches shallow water, so the sunlit zone supports the most producers and life.
Select all true statements about aquatic biomes.
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Many aquatic biomes are marine (salt water), not freshwater. The other three are correct.
Do not sort aquatic biomes by temperature — sort them by salinity. Fresh versus salt water is the key divide, because most organisms can survive in only one. A fish from a river would die in the sea, and vice versa.
An estuary at work:
- A river carries fresh water and nutrients down to the coast.
- Where it meets the salty sea, the two mix into brackish water.
- The rich mix of nutrients feeds huge amounts of life — which is why estuaries are vital nurseries for fish.
Aquatic biomes are divided mainly by salinity: freshwater (lakes, rivers) has little salt, marine (ocean, reefs) is salty, and an estuary is the brackish mix where a river meets the sea. Because sunlight reaches only shallow water, most life is found near the surface.