Zhàn zài mángmáng cānghǎi biān, tā gǎndào zìjǐ de miǎoxiǎo.
Standing by the vast deep-blue sea, he felt his own smallness.
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usage
沧 describes the deep blue-green of a vast sea: 沧海 (the great blue ocean). The famous 沧桑 (lit. 'blue sea to mulberry fields') means the great changes life brings over time.
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The 'cold' sense is literary and archaic, found in classical texts rather than modern speech.