:sl:
There are many verses in the Qur'an were Allaah :swt: directs us to observe what is on the Earth, this doesn't only apply to the land masses but the whole earth, including the oceans, seas, rivers. There are also many verses in the Qur'an that specifically mention the seas/oceans and what they contain. The following are some of them;
And [He has subjected] whatever He multiplied for you on the earth of varying colors.
Indeed in that is a sign for a people who remember.
And it is He who subjected the sea for you to eat from it tender meat and to extract from it ornaments which you wear.
And you see the ships plowing through it, and [He subjected it] that you may seek of His bounty; and perhaps you will be grateful.
[An-Nahl verses 13-14]
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And how many a creature carries not its [own] provision. Allah provides for it and for you. And He is the Hearing, the Knowing.
[Surat 42, verse 60]
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Anything you catch in the sea is lawful for you, and all food from it, for your enjoyment and that of travellers…
[Surat 5 verse 96]
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He released the two seas, meeting [side by side]; Between them is a barrier [so] neither of them transgresses.
So which of the favors of your Lord would you deny?
From both of them emerge pearl and coral. So which of the favors of your Lord would you deny?
And to Him belong the ships [with sails] elevated in the sea like mountains. So which of the favors of your Lord would you deny?
[Surat 55 verses 19-25]
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If we only reflected on the verse that mentions pearls and the coral, or even only reflected on the pearl and how it is made, that would be more than enough.
Allaah knows best!