Alex Mustard / Yellow cabbage coral (Turbinaria reniformis) growing on a coral reef, surrounded by scalefin anthias: Pseudanthias squamipinnis. Ras Mohammed National Park, Sinai, Egypt. Red Sea

Tony Wu / Skeleton shrimp (Caprella bispinosa) female and babies on Sea lettuce. Venomous spikes on female used to protect young. Hokkaido, Japan. May.

Gary Bell/ Oceanwide / Sea Lettuce (Ulva australis) and other alga, Hopkins Island, South Australia, Australia

Nick Upton / Seaweeds including Thongweed / Sea thong (Himanthalia elongata), Tangleweed kelp (Laminaria digitata), Toothed wrack (Fucus serratus) and Dulse (Palmaria palmata). Exposed on rocky shore on low spring...

Alex Mustard / Cabbage coral / lettuce coral (Echinopora lamellosa) growing in shallow water. This coral grows at 5mm per year, so have been growing in this spot for more than 1000 years. Manado Bay, Manado, North S...

Linda Pitkin / Coral reef with Anthias fish (Pseudanthias squamipinnis) and Twotone chromis (Chromis dimidiata) around Yellow scroll coral (Lettuce coral) (Turbinaria reniformis). With diver Jackson Reef, Straits...

Linda Pitkin / Coral reef with Anthias fish (Pseudanthias squamipinnis) and Twotone chromis (Chromis dimidiata) around Yellow scroll coral (Lettuce coral) (Turbinaria reniformis) Jackson Reef, Straits of Tiran, R...

Solvin Zankl / Red dulse (Palmaria palmata) on white background, from Roscoff, France, April. Preserved specimen.

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

Solvin Zankl / Dried Sea lettuce algae (Ulva sp.), Roscoff, France, April.

Alex Mustard / Details of ruffled mantle extensions on the Sacoglossan sea slug (Tridachia crispata) These also contain the chloroplasts of their algae food, that continue to photosynthesise inside the mollusc and p...

MYN / Carsten Krieger / Sea Lettuce (Ulva lactuca) on Common Limpet (Patella vulgata) from tide pool, County Clare, Republic of Ireland, December. Meetyourneighbours.net project