5.4p92-93

5.4 What are the major types of aquatic systems?

Most of the earth is covered with water
1.four ocean: Atlantic, Arctic ocean北冰洋, Pacific, and Indian ocean. (five oceans: + southern ocean南冰洋)
2.aquatic life zone are classified into two major types: saltwater and freshwater
precious貴重的,寶貴的
film薄層;薄膜
equivalent相等的,相同的

Most aquatic species live in top, middle, or bottom layers of water
3.several types of organisms: plankton浮游生物(phytoplankton, zooplankton), nekton游行動物, benthos底生生物, decomposers.
4.surface, middle, and bottom layer. limit factors: temperature, access to sunlight for photosynthesis, dissolved oxygen content, and availbaility of nutrients.
dweller居民
barnacle藤壺
spot地點
worm蟲,蠕蟲
burrow洞穴,地道
euphotic zone光亮帶, 水之最上層
marine snow海雪