A study in 2017, trying to understand why and how microplastics are getting in the marine food chain, found that when coral were offered plastic, sand and bacteria-covered plastic + sand they actually preferred the naked-plastic. They even retained the plastic for longer compared to the other food. They suspect that some types of plastic contain chemicals which stimulate the corals - which are tiny animals related to jellyfish - to feed. Or in other words, plastic is tasty for corals.
Biomining also could be cheaper and greener than traditional mining, using less water and emitting less CO2 than conventional crushing, heating and chemical processes. Biomining works at much lower temperatures and pressures than normal techniques reducing the electricity bill and resources used to get the metal out of the rock.