Solvin Zankl / Kelp forest (Laminaria hyperborea), Atlantic Ocean, North West Norway, March.

Solvin Zankl / Tiny crab on Broad-toothed Gulfweed (Sargassum fluitans) Sargassum Community. Sargasso Sea, Bermuda

Juergen Freund / Detail of Giant kelp (Macrocystis pyrifera) gas-filled bladders (pneumatocysts) Vancouver Island, British Columbia, Vancouver Island, Canada.

Pascal Kobeh / Group of California sea lions (Zalophus californianus) in a kelp forest (Macrocystis pyrifera), California, USA. Pacific ocean.

Pascal Kobeh / Group of California sea lions (Zalophus californianus) swimming in kelp forest (Macrocystis pyrifera), California, USA. Pacific ocean.

Alex Mustard / Scenic view of a bull kelp forest (Nereocystis luetkeana) with sunlight shining through the fronds. Browning Pass, Port Hardy, Vancouver Island, British Columbia. Canada. North East Pacific Ocean.

Chris Gomersall / 2020VISION / European river otter (Lutra lutra) cub amongst kelp on shoreline, Shetland Isles, Scotland, UK, October.

Alex Mustard / A raft of sargasso weed (Sargassum natans) in open ocean. Off shore, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Franco Banfi / Bladder wrack (Fucus sp) exposed at low tide. Vrangel Bay, Primorsky Krai, Russia. August.

Franco Banfi / Bladder wrack (Fucus sp) exposed at low tide. Vrangel Bay, Primorsky Krai, Russia. August.

Franco Banfi / Bladder wrack (Fucus sp) frond on sand at low tide, Vrangel Bay, Primorsky Krai, Russia. August.

Tony Wu / Korean sandlance (Hypoptychus dybowskii) egg clusters on Sargassum (Sargassum horneri). Fish produce sticky secretion in kidneys that adheres eggs to Sargassum. Hokkaido, Japan. May.