Blog post

Life under the seas

Exploring symbiosis in species

colour illustration showing a coral reef with swimming fish
Marijke Everts (opens in new window) (Europeana Foundation)

Under the sea, more than 228,000 species live - vast oceans of biodiversity. In this blog, we dive underwater to explore how some species have adapted for survival.

Different species have survival mechanisms in place to protect their homes and feeding grounds, leading to interesting symbiotic relationships. 

Coral reefs are home to at least 25% of underwater species. They are commonly found in tropical waters and at shallow depths. 

Coral reefs protect and support themselves by secreting hard carbonate external skeleton. They provide complex and diverse habitats that support a variety of other organisms. There may perhaps be as much as 8,000 species of fish residing within the ecosystems of coral reefs around the world. 

colour illustration of three yellow and silver fish swimming above a coral reef
colour photograph, blue and black fish swimming in coral reef
colour photographs, orange / red spotted fish swimming in a coral reef

Corals provide shelter and food for herbivorous fish and, in return, these fish protect corals from seaweeds that can damage and kill corals.

Corals can send out chemical signals when under attack by toxic seaweeds that alert fish like gobies to come and feast. The goby fish themselves develop toxins from eating the seaweed thus becoming less desirable prey. 

colour photograph of a yellow fish specimen

Anemone fish are amongst those who've adapted to be unaffected by the sea anemone's stinging cells. The fish use the anemones as their home, being protected from other predators, while, on the other hand, the sea anemone uses faeces from the fish as nutrients. 

black and white illustration of a sea anemone and three star fish
colour photograph of a brown and white fish

The relationships between these underwater species are essential to their survival, each playing specific roles that benefit the other allowing for their ecosystem to continue functioning.

nature fish Europeana