162
R. K. DELL
(Jaderholm) and some tunicates together with several hundreds of
associated species produces a total biomass of 3 kg/m2.
The practical absence of algae (except for Phyllophora) may be an
unusual feature in this area.
Comparative sampling at Molodezhnaya off Enderby Land was
reported by Gruzov and Pushkin (1970).
Off Molodezhnaya, in contrast t o the locality sampled off the
Haswell Islands, there were extensive muddy and sandy areas. On
steep rocky coasts snow drifts on the ice shelves block most of the light.
Here the sequence of organisms is much as that recorded at Mirny.
The upper zone is lifeless (down to 7 or 8 m). From 8 to 16 m
Odontaster validus, Sterechinus neumayeri, sponges and small colonies of
the alcyonarian Eunephthya occur.
Near low coasts, the ice is fairly transparent and snow drifts are
lacking. Here a much greater development of plant life takes place.
Below the lifeless zone (2-6 m) a rich growth of diatoms occurs. Below
this a zone of algae is well marked with two or three species of red algae
extending to a depth of 10 m and the brown algaewith Odontaster validus,
Sterechinus neumayeri, sponges, the nemertine Lineus and polychaetes.
From 30 to 60m no algae remain but Sterechinus is abundant with
sponges, ascidians, alcyonarians, echinoderms, pycnogonids and
Crustacea. This zone resembles the sponge community at Mirny.
The muddy and sandy habitats were sampled only down to about
16 m. The infauna consisted of the bivalve Laturnda, sea urchins
(Abatus sp.) and polychaetes, with Odontaster and some gastropods as
epifauna.
McCain and Stout (1969) gave a preliminary account of two transect
stations near Arthur Harbour, Antarctic Peninsula, selected to show
the zonation of benthos on vertical rock faces. The faces were nearly
vertical down to about 46 m where they met gently sloping mud. Surf
action seemed to extend down to about 16 m, resulting in murky water
above this depth. From the surface to 8 m the limpet Patinigera
poZaris and encrusting algae were the main organisms present on flat
surfaces with the large sea urchin, Sterechinus neumayeri and the brown
alga, Desmarestia in cracks and crevices.
From 8 to 15 m the dominant organism was the kelp PhyZEogigas
grandifolius under the cover of which the isopod, Glyptonotus antarcticus, and many other invertebrates occurred. Below 16 m the rock
surface had a heavy silt cover. Some kelp zone animals extended downwards through this zone while gorgonian corals, siliceous-spiculed
sponges and nemerteana occurred in the lower limits. Three zones
between the surface and about 30 m were therefore distinguished :
R. K. DELL
(Jaderholm) and some tunicates together with several hundreds of
associated species produces a total biomass of 3 kg/m2.
The practical absence of algae (except for Phyllophora) may be an
unusual feature in this area.
Comparative sampling at Molodezhnaya off Enderby Land was
reported by Gruzov and Pushkin (1970).
Off Molodezhnaya, in contrast t o the locality sampled off the
Haswell Islands, there were extensive muddy and sandy areas. On
steep rocky coasts snow drifts on the ice shelves block most of the light.
Here the sequence of organisms is much as that recorded at Mirny.
The upper zone is lifeless (down to 7 or 8 m). From 8 to 16 m
Odontaster validus, Sterechinus neumayeri, sponges and small colonies of
the alcyonarian Eunephthya occur.
Near low coasts, the ice is fairly transparent and snow drifts are
lacking. Here a much greater development of plant life takes place.
Below the lifeless zone (2-6 m) a rich growth of diatoms occurs. Below
this a zone of algae is well marked with two or three species of red algae
extending to a depth of 10 m and the brown algaewith Odontaster validus,
Sterechinus neumayeri, sponges, the nemertine Lineus and polychaetes.
From 30 to 60m no algae remain but Sterechinus is abundant with
sponges, ascidians, alcyonarians, echinoderms, pycnogonids and
Crustacea. This zone resembles the sponge community at Mirny.
The muddy and sandy habitats were sampled only down to about
16 m. The infauna consisted of the bivalve Laturnda, sea urchins
(Abatus sp.) and polychaetes, with Odontaster and some gastropods as
epifauna.
McCain and Stout (1969) gave a preliminary account of two transect
stations near Arthur Harbour, Antarctic Peninsula, selected to show
the zonation of benthos on vertical rock faces. The faces were nearly
vertical down to about 46 m where they met gently sloping mud. Surf
action seemed to extend down to about 16 m, resulting in murky water
above this depth. From the surface to 8 m the limpet Patinigera
poZaris and encrusting algae were the main organisms present on flat
surfaces with the large sea urchin, Sterechinus neumayeri and the brown
alga, Desmarestia in cracks and crevices.
From 8 to 15 m the dominant organism was the kelp PhyZEogigas
grandifolius under the cover of which the isopod, Glyptonotus antarcticus, and many other invertebrates occurred. Below 16 m the rock
surface had a heavy silt cover. Some kelp zone animals extended downwards through this zone while gorgonian corals, siliceous-spiculed
sponges and nemerteana occurred in the lower limits. Three zones
between the surface and about 30 m were therefore distinguished :