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5 stars - Fully protected as a national park or Natura 2000 site by national legislation
MarBEF Deep Sea and Open Ocean Reference Site

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Porcupine Seabight Photo:

Synoptic description of site:

The Porcupine Abyssal Plain is a flat, vast expanse of muddy seabed with occasional, scattered rocky abyssal hills. The area covers an area about half the size of the European landmass. The depth varies between 4000 and 4850m

Habitats present:

Deep-Sea BedRockSandMudBiohermBenthopelagicWater Column
Continental Margin     Epi-pelagic  
Abyssal Plain  X  Mesopelagic  
Seamounts and
Oceanic Islands flanks
X    Bathypelagic  

Description of fauna and flora:

The fauna has been well documented as part of previous large-scale EU projects. Data are available on microorganisms, meiofauna, macrofauna, invertebrate megafauna and fish. The large invertebrates (megafauna) on the Porcupine Abyssal Plain are dominated by the holothurians (sea cucumbers). They contribute about 90% to the total abundance and biomass of the megafauna. Typical species are Psychropotes longicauda, Oneirophanta mutabilis and Pseudostichopus villosus. In recent years there has been a population explosion of another holothurian species, Amperima rosea. Other important fauna include the mud swallowing asteroids (seastars) Hyphalaster inermis and Styracaster chuni and a variety of sea anemones (actinarians). Small Grimpoteuthis spp. octopods, pycnogonids (sea spiders) and tunicates also occur there.

Habitat description:

Habitats according to EUNIS classification:

A5.53 Communities of abyssal muds
A6.23 Deep summit communities of seamount, knoll or bank (i.e. below mesopelagic zone)


The distances from PAP are: from SW and W Ireland at 1 day, from SW England at 1.5 days, from NW Spain at 1.5 days, from W France at 2 days. Accessible all year round, but very stormy in winter. An oceanographic vessel capable of working in 4800m of water depth is needed.

Available database and website:

Data on major taxa available in database format from 1989 for megafauna. Not published on web pages, but available through scientific collaboration.

Time-series data:
The fauna has been well documented as part of previous large-scale EU projects. Data are available on microorganisms, meiofauna, macrofauna, invertebrate megafauna and fish. A time series from 1989 to present shows evidence of large-scale regime shifts, probably in relation to inter-annual variability in surface primary production and the downward flux of organic matter from surface waters.

Dataset covering this area:

Commitment and ongoing research:

A central location on the Porcupine Abyssal Plain is the site of the "EU Deep-sea Time Series Station" sampled in EU FP II, III,and IV projects. The central location is often referred to as the BENGAL Site following the work there by the FP IV project on "High resolution temporal and spatial study of the BENthic biology and Geochemistry of a northeastern Atlantic abyssal Locality (BENGAL)". The site is now part of the UK Core Strategic Project BICEP (Biophysical Interactions and Controls on Export Production) funded by the Natural Environment Research Council. It is likely that the time series will form the basis of a future 5-year UK research project linking long-term change in surface water processes, export flux and the deep seabed. There is a new cooperative agreement to study the Porcupine abyssal plain time series in a MARBEF Responsive Mode Project, involving the creation of 2 new collaborative PhD studentships (2005-2009).

Additional Information:

Billett D.S.M. (2001) (Ed.). High-Resolution Temporal and Spatial Study of the Benthic Biology and Geochemistry of a Northeastern Atlantic Abyssal Locality. Progress in Oceanography 50 (Special Edition).
Thiel, H.J. & Rice, A.L. (1995) (Eds.). Structure and variability of the deep-sea benthos – results from EU funded research. Internationale Revue der Gesamten Hydrobiologie 10 (2).
Thurston, M.H., Bett, B.J., Rice, A.L. & Jackson, P.A.B. (1994). Variations in the invertebrate megafauna in the North Atlantic. Deep-Sea Research 41, 1321-1348.
Billett, D.S.M., Bett, B.J., Rice, A.L., Thurston, M.H., Galéron, J., Sibuet, M. and Wolff, G.A. (2001) Long-term change in the megabenthos of the Porcupine Abyssal Plain (NE Atlantic). Progress in Oceanography 50, 325-348
Vangriesheim A, Springer B, Crassous P , 2001.Temporal variability of near-bottom particle resuspension and dynamics at the Porcupine Abyssal Plain, Northeast Atlantic. Progress in Oceanography 50 (1-4): 123-145 Sp. Iss. SI
Galeron J, Sibuet M, Vanreusel A, Mackenzie K, Gooday AJ, Dinet A, Wolff GA, 2001. Temporal patterns among meiofauna and macrofauna taxa related to changes in sediment geochemistry at an abyssal NE Atlantic site. Progress in Oceanography 50 (1-4): 303-324 Sp. Iss. SI
Bett BJ, Malzone MG, Narayanaswamy BE, Wigham BD, 2001 Temporal variability in phytodetritus and megabenthic activity at the seabed in the deep Northeast Atlantic. Progress in Oceanography 50 (1-4): 349-368 Sp. Iss. SI