Nick Upton / Irish moss / Carrageen (Chondrus crispus) attached to rocks, exposed at low tide. Treyarnon Bay, Cornwall, England, UK. September.

Solvin Zankl / Sea lettuce algae (Chondrus crispus) from Roscoff, France. Preserved specimen.

Solvin Zankl / Intertidal rocks covered in seaweeds, including brown algae: Toothed wrack (Fucus serratus), and Thongweed (Himanthalia elongata), red algae: left Chylocladia verticillata, middle Pepper Dulse (Osmu...

Sue Daly / Irish Moss (Chondrus crispus) English Channel, off the coast of Sark, Channel Islands, July

Nick Upton / Irish moss / Carrageen (Chondrus crispus) iridescing in a sunlit rockpool, Rhossili, The Gower peninsula, UK, July.

Nick Upton / Netted dog whelks (Nassarius reticulatus) scavenging on rocks among Sea Lettuce (Ulva lactuca) and Irish moss / Carrageen (Chondrus crispus) seaweeds exposed on a low spring tide, Rhossili, The Gower...

Nick Upton / Green form of Irish moss / Carrageen (Chondrus crispus) growing in a rockpool, North Berwick, East Lothian, UK, July.

Nick Upton / Split level view of Irish moss / Carrageen (Chondrus crispus) iridescing in a sunlit rockpool alongside Coralweed (Corallina officinalis) and Sea Lettuce / Green laver (Ulva lactuca). Rhossili, The Go...

Jordi Chias / Fish (Nototheniidae) and two starfish hiding amongst seaweed (probably Sarcopeltis antarctica) on the seabed, Antarctic Peninsula, Antarctic Ocean.

Jordi Chias / Seaweed, (probably Sarcopeltis antarctica) on the seabed, Deception island, Antarctic Peninsula, Antarctic Ocean.

David Hall / Split level shot of kelp and other 'seaweeds' partly exposed at low tide, with coniferous forest in the background. Seen in this photograph are the following: Turkish washcloth (Mastocarpus pa...

Philippe Clement / Gigartina pistillata, red alga washed ashore on rocky beach, Normandy, France, June