an ecosystem (system of an ecological community and its environment)

abundant, wealthy, plentiful, fully sufficient

beautiful

(archaic) beautiful

atoll

ecology, mode of life of living creatures / way of life, the way people live

a sea, an ocean / a lake / (figuratively) an object covering over a large area, as in 血の海 (chi no umi, “pool of blood”) or 火の海 (hi no umi, “sea of fire”)

system, family / style

to know, be aware of / to learn, acquire, / to be acquainted with, to know (someone) / (colloquial, in the negative) to care in the least about, to be concerned with,

stem or continuative form of 知る (shiru) [godan]