Our oceans are in an ecological crisis due to their contamination with millions of tons of toxic microplastic particles. In just a few years, the volume of microplastic particles will exceed that of plankton in our oceans and turn them into a huge sea of plastic. This publication brings together numerous international art projects related to environmental activities, DIY biotechnology, and science, and draws attention to the irreversible destruction of our marine ecosystems - the current threat posed by the loss of marine animal biodiversity, for example, or the decline in oxygen production due to massive plankton loss. It also presents current scientific findings on sustainable alternatives to plastic.