1. Cold-water coral
reefs
Christopher Hinchcliffe
AKVA
Photo from (1), pp. 7

2. Environmental Requirements
1
 Sufficient food supply
 Any particulate/dissolved organic matter
 Phytodetritus, zooplankton faeces,
zooplankton
 Dissolved inorganic carbon levels (DIC)
and seawater density
 DIC <2170 µmol/kg, ρ: 27.35 – 27.65 kg/m3
=> High quality reef
 DIC >2170 µmol/kg, ρ: <27.35 / >27.65
kg/m3 => Low quality reef
 Temperature: 4 – 14oC; (6 – 9oC)
 Salinity: 32 – 38.8; (~ 35)
 Oxygen: 3.8 – 7.2 ml/L; (6.0 – 6.2 ml/L)
Photo from (1), pp. 13

3. Reproduction
 Asexual (cloning) 1
 Fragmentation
 Responsible significant
proportion of reef building
 Sexual reproduction 1
 Separate sexes
 Broadcast spawners
 Spawning February – March
(in pipeline area)

4. Larval Drift
 Genetically distinct offshore and fjord
populations 2
 Fjord populations more isolated (bottlenecked)
 Strong local recruitment on the slope 2
 Moderate gene flow recorded between slope
sub-populations 2
 Fjords much more highly differentiated
 Shelf Edge Current (Iberian Margin to
Norwegian Sea) capable of transporting
larvae
 Larvae planktonic for 3 – 5 weeks
 Larvae will settle on any hard substrate
Image from
http://oceancurrents.rsmas.miami.edu/atlantic/img_mgs
va/slope-YYY.gif

5. Trawling
 Grossly destructive
 30 – 50% of Norwegian reefs
impacted/destroyed 3
 Continuous, wide-spread
impact
 Areas trawled until no fish
left (i.e. no habitat (coral) left
for fish to inhabit)
 Direct impact of trawl gear
 Indirect impact of suspended
sediment
 Trawled sediments may drift
to protected areas
Top image from (3) ; bottom image from (4)

6. Oil
Installations
 Coral first described on North
Sea oil installations in late
1990s 5
 Numerous records since 6
 Growth rates of 26 ± 5 mm yr -
1 6
 Only very localised effects of
muds and cuttings.
 Tolerant to weeks of low level
elevated sediments 1
 Larvae most susceptible
 Time activities outside
spawning/recruitment
Images from (6)

7. Restitution
 Fosså et al (2002)
suggest restitution to
small colonies over 100s
years, full reefs after
1000s.
 Possibly a little
conservative given recent
growth estimates.
 Tropical reefs from
otherwise undisturbed
areas show high
resilience
 Full community restitution
likely to fall outside 10
year window
Image from (4)

8. References
1. Järnegren, J. & Kutti, T. 2014. Lophelia pertusa in Norwegian waters. What have we
learned since 2008? – NINA Report 1028. 40 pp.
2. Le Goff-Vitry MC, Pybus OG, Rogers AD (2004) Genetic structure of the deep-sea
coral Lophelia pertusa in the northeast Atlantic revealed by microsatellites and
internal transcribed spacer sequences. Molecular Ecology 13:537-549
3. Fosså JH, Mortensen PB, Furevik DM (2002) The deep-water coral Lophelia pertusa
in Norwegian waters: distribution and fishery impacts. Hydrobiologia 471:1-12
4. Roberts JM, Wheeler AJ, Freiwald A (2006) Reefs of the deep: The biology and
geology of cold-water coral ecosystems. Science 312:543-547
5. Bell, N. & J. Smith, 1999. Coral growing on North Sea oil rigs. Nature 402: 601.
6. Gass SE, Roberts JM (2006) The occurrence of the cold-water coral Lophelia
pertusa (Scleractinia) on oil and gas platforms in the North Sea: Colony growth,
recruitment and environmental controls on distribution. Marine Pollution Bulletin
52:549-559