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Why did stromatolites decline after about 700 million years ago?

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A detailed geologic time scale chart displaying Earth's history from the Hadean Eon over 4.5 billion years ago to the present, organized by eons, eras, periods, epochs, and ages with color-coded columns and corresponding dates in millions of years. — Precambrian The stratigraphic chart of geologic time.

Stromatolites, which are layered structures formed by communities of microorganisms such as blue-green algae, reached their peak development during the late Proterozoic. However, they began to decline significantly in number starting about 700 million years ago.1

The primary scientific hypothesis for this decline is the emergence and proliferation of metazoans—multicelled organisms with differentiated tissues and organs. It is believed that these newly evolved animals consumed the stromatolitic algae and that their active growth and movement destroyed the delicate habitats required for the algae to form these layered mats.1