“Most people are completely unaware of what is in the water,” says Julian Cremona, a naturalist and photographer who is out to change that with his new book.
Plankton is an umbrella term for all kinds of different organisms floating in our waters, from plants, known as phytoplankton, to animals, known as zooplankton. They can be as little as 0.02 micrometres, the size of some viruses, or as big as 2 metres, the size of a large jellyfish. What they have in common is that they aren’t powerful enough to overcome the movement of water, unlike organisms that can resist the current. As Cremona writes, plankton are “drifting organisms that are unable to determine their long-term direction and are at the whims of the current”.
Cremona’s book is a guide to the different types of plankton found along the British coast, such as the larva of a Magelona worm, just 2 millimetres in size, in the main image. To take this photograph, Cremona fitted objective lenses from an old microscope to his camera.
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Below is a shot of a tiny zooplankter, Oikopleura. Its body is made up of a trunk on top of a long tail, ranging from a few millimetres to a centimetre long. It has a lifespan of five to six days, over which it grows, reproduces and finally dies.
Some larger plankton are shown below, including a handful of compass jellyfish (Chrysaora hysoscella), which are mostly found in northern Europe. The umbrella of this jellyfish can stretch to 30 centimetres in diameter, and it uses its 24 tentacles to catch its food: small fish, crabs and other jellyfish.
Pictured below is a swarm of moon jellyfish (Aurelia aurita), the most common jellyfish to be found in the UK’s waters.
Some phytoplankton exhibit symbiosis with jellyfish and sea anemones, such as the aptly named snakelocks anemone (Anemonia viridis), pictured below. Single-celled Symbiodinium plankton live within the tissue of its green tentacles, where they perform photosynthesis and provide their host with carbohydrates. In return, the plankton receive inorganic carbon, nitrogen, phosphate – and a protected refuge in which to live.
