Introducing Cold-Water Corals

 Until recent years Coral reefs were a phenomena only associated with the tropics, but recent advances in technology have allowed us to realise the range of latitudes that these corals can habituate. Realisation of their existence was first discovered by scientists when dredged specimens of coral were hauled up from the deep by fishermen (URL 1). 


The first studies into the biology of cold water corals were made by Phillip Henry Gosse in the mid 19th century (Roberts et al. 2009). This triggered many expeditions one of the most significant being a voyage by HMS Challenger (1872-76) which revolutionised our understanding of the wealth of life present at depth: 4000 new species were discovered at depths of 5500 meters. This dismissed Edward Forbes Azoic Theory that no life could exist below 600 metres (Roberts et al. 2009).
 

Cold-water corals inhabit a wide range of marine habitats across the globe, from abyssal plains to continental slopes and inland fjords (Roberts et al. 2009). These key ecosystems can be found at depths ranging 40 to over 1000 metres. They are found in all temperate oceans in temperatures as low as 4oC (URL 1). They can form stunning reefs rising over 35 metres above the sea floor and stretching for miles (URL 1). They create a wide array of micro-habitats for many animals. These corals vary in longevity but even after death the skeletal structures can still provide a habitat for colonies of organisms. Rost Reef is an example of a cold-water reef found in Norway, it is over 8,500 years old dating back to the last Ice Age (Freiwald et al 2004). 

Many discoveries of cold-water coral reefs are as a result of human activity and exploitation of deep water resources. Newly discovered reefs often showed signs of destruction and scars from commercial fishing activities (Figure 1). Their vulnerability and damage showed the need for international action to conserve these ecosystems: localised action by protection of surrounding waters was not enough (Freiwald & Roberts 2005).  
Already half of known cold water corals have been destroyed by anthropogenic activities mainly as a result of destructive fishing practices. This huge loss is disturbing especially considering that 40% of current fishing grounds occur in the same area as these corals (URL 1).
 

Figure 1: Cold-water coral reef - A comparison of an untrawled area (a,b) and trawled area (c,d) showing extent of damage (Replicated from Roberts et al. 2009)

 

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