Plankton has become a lovely obsession for my work in the past couple of years. It forms the base of the oceans’ food chain, provides half of our oxygen, is a crucial sink for carbon dioxide - and is spectacularly beautiful. But it’s mostly invisible to the naked eye and if we can’t see something, we tend not to care about it. Plankton is under threat from increasing acidification, warming and pollution of the oceans. My ongoing Importance of Plankton series is a celebration of plankton’s beauty with a view to increasing awareness of its fragility.