Sea Around Us Project member Villy Christensen is author on a paper that provides first-ever estimate of worldwide fish biomass and impact on climate change. Read the press release and the full study published in Science (here also is a link to the associated ‘perspective’ article). Below is a video animation of fish excreting pellets of calcium carbonate, a chalk-like substance also known as “gut rocks,” in a process completely separate from food digestion (animation by Dalai Felinto).