138
Lisa A. LEVIN and Andrew J. GOODAY
the Goban Spur transect (Flach et al., 1998). The
densities of suspension feeders, however, were particularly high within a zone on the upper slope (1000–
1500 m water depth) subject to high current velocities.
Submersible observations indicate that suspensionfeeding megafauna are also common on hard steep
substrates (<1000 m depth) to the west of the Porcupine
Bank and Goban Spur (Tyler and Zibrowius, 1992). The
most common taxa observed by Tyler and Zibrowius
(1992) were sponges, cnidarians (actiniarians, corals,
zoantharians, ceriantharians, antipatharians, alcyonarians and particularly gorgonians) and echinoderms
(mainly crinoids, asteroids and ophiuroids). A crinoiddominated zone between 2100 and 2600 m depth
was associated with a northward-flowing water mass
reaching velocities of 7 cm s
−1 .
French and Iberian margins
Bay of Biscay: There has been a long history of
French research along the Bay of Biscay continental
margin and on the adjacent abyssal plain, starting in the
1880s with the Travailleur and Talisman campaigns (Le
Danois, 1948; Rice, 1980). A century later, the eleven
cruises organized by Biologie Gascogne (BIOGAS)
between 1972 and 1981 yielded a considerable body
of quantitative information on many aspects of the
Biscay benthos (Sibuet, 1977; Laubier and Sibuet,
1979; Laubier and Monniot, 1985). The megafauna
was sampled using a large beam trawl and evaluated
photographically; macro- and meiofauna and bacteria
were sampled using an epibenthic sled, and Reineck
and USNEL box corers. The extensive BIOGAS
collections were studied by numerous scientists from
many countries, resulting in a long list of publications.
In particular, the volume edited by Laubier and
Monniot (1985) includes data on different faunal
groups (from bacteria to megafauna), necrophages, and
particular higher taxa, as well as processes such as
sediment recolonization and particle fluxes. Laubier
and Monniot (1985) have also given a comprehensive
list of BIOGAS publications, which include both
taxonomic and ecological studies.
The BIOGAS program centered around six intensively worked stations, four located in the northern
part of the Bay (stations 1–4: 1920–4825 m depth) and
two in the southern part (stations 5–6: 1894–4475 m
depth), extending from the continental slope out onto
the continental rise and abyssal plain (Laubier and
Sibuet, 1979). Sibuet and Segonzac (1985) reported
on the ‘megafauna’ from trawl samples, although they
examined the fraction >1 mm and therefore included
animals more appropriately considered as macrofauna.
The megafauna show greater heterogeneity, both across
the Bay and at particular stations, than do the
meiofauna and macrofauna. Densities decreased by
a factor of 9 from the shallowest to the deepest
station along the northern transect (2924 individuals
m
−2 to 321 individuals m
−2 ). The shallowest station
(#1: 1920–2245 m), on the Meriadzek Terrace was
particularly rich and diverse, with cnidarians (actiniarians) and echinoderms making up about twothirds of the fauna. Molluscs were abundant (34%)
at station 3 (4134–4240 m), and ascidians became
fairly important (up to 14% of the fauna) at the
deepest station (#4: 4706–4825 m). Fewer animals were
present at the two southern stations; for example, at
station 5 on the continental slope (1894–1995 m) the
faunal density was 440 individuals ha
−1 , much lower
than at comparable depths on the Meriadzek Terrace
(2924 individuals ha
−1 ). In the south, too, echinoderms
(mainly holothurians), were relatively more important
than on the northern margin (Sibuet, 1977; Sibuet and
Segonzac, 1985). These north-to-south differences in
assemblages of larger invertebrates within the Bay of
Biscay probably reflect the greater terrigenous input
(including plant material) in the southern area, much of
it presumably channeled down submarine canyons.
Biogenic traces visible in seafloor photographs
showed a good correlation with abundance of animals
(>1 mm) across bathymetric gradients, and, in agreement with animal densities, were more prevalent at the
northern than at the southern sites (Mauviel and Sibuet,
1985). Trace densities were greatest on the Meriadzek
Terrace, but their diversity was highest at station 3,
close to the lower end of the Shamrock Canyon, where
23 of the 29 categories recognized by Mauviel and
Sibuet (1985) occurred. The traces included a wide
variety of tracks, burrows, and mounds, as well as
holothurian fecal casts.
Data on the macrofauna, both sensu strictu (>250 mm
fraction, macrofaunal taxa only) and sensu lato
(>250 mm fraction, all taxa), from BIOGAS stations 1–
3 in the northern Bay of Biscay (2100–4100 m)
are given by Dinet et al. (1985). At 2800 m and
4150 m, the macrofauna appears to be fairly abundant.
Although the comparison is complicated by differences
in mesh sizes, densities at the 2800 m BIOGAS station
(4635 individuals m
−2 , for the >250 mm fraction)
are most similar to values from 1800 m (4320 individuals m
−2 , for the >420 mm fraction) and 2000 m
Lisa A. LEVIN and Andrew J. GOODAY
the Goban Spur transect (Flach et al., 1998). The
densities of suspension feeders, however, were particularly high within a zone on the upper slope (1000–
1500 m water depth) subject to high current velocities.
Submersible observations indicate that suspensionfeeding megafauna are also common on hard steep
substrates (<1000 m depth) to the west of the Porcupine
Bank and Goban Spur (Tyler and Zibrowius, 1992). The
most common taxa observed by Tyler and Zibrowius
(1992) were sponges, cnidarians (actiniarians, corals,
zoantharians, ceriantharians, antipatharians, alcyonarians and particularly gorgonians) and echinoderms
(mainly crinoids, asteroids and ophiuroids). A crinoiddominated zone between 2100 and 2600 m depth
was associated with a northward-flowing water mass
reaching velocities of 7 cm s
−1 .
French and Iberian margins
Bay of Biscay: There has been a long history of
French research along the Bay of Biscay continental
margin and on the adjacent abyssal plain, starting in the
1880s with the Travailleur and Talisman campaigns (Le
Danois, 1948; Rice, 1980). A century later, the eleven
cruises organized by Biologie Gascogne (BIOGAS)
between 1972 and 1981 yielded a considerable body
of quantitative information on many aspects of the
Biscay benthos (Sibuet, 1977; Laubier and Sibuet,
1979; Laubier and Monniot, 1985). The megafauna
was sampled using a large beam trawl and evaluated
photographically; macro- and meiofauna and bacteria
were sampled using an epibenthic sled, and Reineck
and USNEL box corers. The extensive BIOGAS
collections were studied by numerous scientists from
many countries, resulting in a long list of publications.
In particular, the volume edited by Laubier and
Monniot (1985) includes data on different faunal
groups (from bacteria to megafauna), necrophages, and
particular higher taxa, as well as processes such as
sediment recolonization and particle fluxes. Laubier
and Monniot (1985) have also given a comprehensive
list of BIOGAS publications, which include both
taxonomic and ecological studies.
The BIOGAS program centered around six intensively worked stations, four located in the northern
part of the Bay (stations 1–4: 1920–4825 m depth) and
two in the southern part (stations 5–6: 1894–4475 m
depth), extending from the continental slope out onto
the continental rise and abyssal plain (Laubier and
Sibuet, 1979). Sibuet and Segonzac (1985) reported
on the ‘megafauna’ from trawl samples, although they
examined the fraction >1 mm and therefore included
animals more appropriately considered as macrofauna.
The megafauna show greater heterogeneity, both across
the Bay and at particular stations, than do the
meiofauna and macrofauna. Densities decreased by
a factor of 9 from the shallowest to the deepest
station along the northern transect (2924 individuals
m
−2 to 321 individuals m
−2 ). The shallowest station
(#1: 1920–2245 m), on the Meriadzek Terrace was
particularly rich and diverse, with cnidarians (actiniarians) and echinoderms making up about twothirds of the fauna. Molluscs were abundant (34%)
at station 3 (4134–4240 m), and ascidians became
fairly important (up to 14% of the fauna) at the
deepest station (#4: 4706–4825 m). Fewer animals were
present at the two southern stations; for example, at
station 5 on the continental slope (1894–1995 m) the
faunal density was 440 individuals ha
−1 , much lower
than at comparable depths on the Meriadzek Terrace
(2924 individuals ha
−1 ). In the south, too, echinoderms
(mainly holothurians), were relatively more important
than on the northern margin (Sibuet, 1977; Sibuet and
Segonzac, 1985). These north-to-south differences in
assemblages of larger invertebrates within the Bay of
Biscay probably reflect the greater terrigenous input
(including plant material) in the southern area, much of
it presumably channeled down submarine canyons.
Biogenic traces visible in seafloor photographs
showed a good correlation with abundance of animals
(>1 mm) across bathymetric gradients, and, in agreement with animal densities, were more prevalent at the
northern than at the southern sites (Mauviel and Sibuet,
1985). Trace densities were greatest on the Meriadzek
Terrace, but their diversity was highest at station 3,
close to the lower end of the Shamrock Canyon, where
23 of the 29 categories recognized by Mauviel and
Sibuet (1985) occurred. The traces included a wide
variety of tracks, burrows, and mounds, as well as
holothurian fecal casts.
Data on the macrofauna, both sensu strictu (>250 mm
fraction, macrofaunal taxa only) and sensu lato
(>250 mm fraction, all taxa), from BIOGAS stations 1–
3 in the northern Bay of Biscay (2100–4100 m)
are given by Dinet et al. (1985). At 2800 m and
4150 m, the macrofauna appears to be fairly abundant.
Although the comparison is complicated by differences
in mesh sizes, densities at the 2800 m BIOGAS station
(4635 individuals m
−2 , for the >250 mm fraction)
are most similar to values from 1800 m (4320 individuals m
−2 , for the >420 mm fraction) and 2000 m