Fig. 2: Relative composition of higher taxonomical groups of th Rosss Sea fauna
A Rauschert-Dredge with a with of 0,5 m and a mesh size of 0,5 mm was used for obtaining the samples (sampling time 5 min.)
Samples were fixed in 96% alcohol (additional samples fixed in 4% borax buffered formalin), sorted by taxon and counted for the study of community composition
Sample areas as indicated in Fig. 1, each area was sampled along a depth transect from 100 m to 500 m
Distribution and composition of macrozoobenthic communities along a Victoria-Land transect (Ross Sea, Antarctica),
with special emphasis on the peracarid crustacean fauna
1 1 2 3
Peter Rehm , Wolf Arntz , Angelika Brandt and Sven Thatje
(1) Alfred Wegener Institute for Polar and Marine Research (AWI), Benthic Ecosystems Comparative Ecosystem Research, Columbusstrasse, D-27568 Bremerhaven, Germany E-mails: prehm@awi-bremerhaven.de, warntz@awi-bremerhaven.de
(2) Zoologisches Institut und Museum, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg E-mail: abrandt@zoologie.uni-hamburg.de
(3) National Oceanography Centre, University of Southampton, European Way, Southampton, UK, SO14 3ZH E-mail: svth@noc.soton.ac.uk
Introduction
The Victoria Land Transect Cruise with the italian research vessel "Italica", carried out in February 2004, was the first large-scale attempt to obtain benthic samples systematically along a latitudinal transect along the Antarctic Ross Sea shelf. Previous surveys emphasized on aspects of fisheries, from there wide-meshed nets were used only. During this cruise, a Rauschert-Dredge with a mesh size of 0,5 mm was used to obtain smaller macrozoobenthic specimens of the Ross Sea community, which were not obtained by preceding sampling. Cumaceans were examined in detail as an example of the small sized peracarids . Previously only 12 species were known from the Ross Sea, now the number of species increased to 33.
Results
Fig. 3: Abundance of higher taxonomical groups of the Rosss Sea fauna
[specimen m ] -2
Fig. 1: Sample areas; I Ross Sea, II Antarctica
Methods
Distribution of higher taxa at sample areas:
crustaceans (71-83%), polychaetes (12-16%), molluscs (3-7%), echinoderms (0-2%)
Increased occurrences: Cape Adare molluscs 38%, Coulman Island polychaetes 63%
In general total abundance increases with decreasing depth (Fig. 3) Exceptions to this rule is location Cape Russell, decreased
abundance in shallow areas might be caused by iceberg scouring
Fig. 4: Relative composition of peracarid taxons (left) and abundance (specimen 10 m-2) of peracarid Fig. 5: Relative composition of cumacean families (left) and abundance (specimen 10 m-2) of cumacean
At the five sample areas, peracarids are dominated by amphipods (32-66%) followed by isopods (13-30%), cumaceans (<1-35%), tanaids (4-28%)and mysidaceans (<1-1%)
At Cape Hallet and Coulman Island the portion of abundance of
cumaceans displays an increase with decreasing depth in addition to an increase of general abundance at these locations
Outlook
As shown by the study the number of cumaceans increased to 275% of the formerly recorded species. For the other peracarid taxa (especially for
isopods and amphipods as the most common peracarids) similar results can be expected. Therefore biodiversity of the Ross Sea will prove to be
considerably richer as supposed up to now.
Tab. 1: Ross Sea species, blue newly recorded
Distribution of the cumacean families:
Leuconidae (8-85%), Nanastacidae (10-92), Dyastilidae (3-16%), Lampropidae (<1-2%) and Bodotriidae (<1%)
Out of 29 collected species 21 were new to the Ross Sea
The number of species recorded for the Ross increased from 12 to 33
Acknowledgements:
Without help of Riccardo Cattaneo Vietti and Mariachiara Chiantore the participation in the italian antarctic research program PNRA S.C.r.l. would not haven been possible.
Special thanks are due to Ute Mühlenhard-Siegel and Daniel Roccatagliata for their assistance in determining cumacean species. Participation on the cruise with RV
”Italica” was supported by the DFG (BR 1121/23-1).
This research was financed by a grand of the University of Bremen.
Taxon Number
Lampropidae
Hemilamprops cf. ultimaspei 7
Paralamprops sp. 3
Bodotriidae
Cyclaspis gigas 17
Vaunthompsonia cf. laevifrons 148 Nanastacidae
Campylaspis cf. antarctica 75
Campylaspis ledoyeri 8
Campylaspis cf. maculata 8
Campylaspis quadridentata 33 Campylaspis quadriplicata 19
Campylaspis sp. A 18
Campylaspis sp. B 50
Cumella australis 779
Cumella cf. emergens 43
Leuconidae
Eudorella cf. gracilior 838
Eudorella cf. sordida 45
Eudorella sp. A 15
Leucon antarctica 1561
Leucon assimilis 171
Leucon intermedius 87
Leucon cf. parasiphonautus 1
Leucon cf. sagitta 276
Leucon sp. A 1099
Diastylidae
Diastylis corniculata 6
Diastylis enigmatica 167
Diastylis helleri 44
Diastylis lecroyae 59
Diastylopsis goeki 7
Leptostylis antipus 43
Makrokylindrus inscriptus 1
AWI
57%
15%
5%
15%
8%
Crustacea Echinodermat Mollusca Polychaeta Sonstige 0
50 100 150 200 250 300 350 400 450
A1 A2
A3 A4
A5
H-out1 H-out2
H-out4
H-in2 H-in3
Hin4 H-in5
C1 C2
SMN R2
R3 R4
Abundance
Crustacea Echinodermat Mollusca Polychaeta Others
north south
-2 [m]
500 m
420 m 300 m 230 m
120 m
460 m
250 m
320 m
390 m
200 m
410 m
340 m 370 m 330 m
320 m 480 m
80 m
360 m
0%
20%
40%
60%
80%
100%
A1 A2
A3 A4
A5
H-out1 H-out2
H-out4
H-in2 H-in3
Hin4 H-in5
C1 C2
SMN1
R2 R3
R4
RelativeAbundance
Cumacea Amphipoda Isopoda Mysidacea Tanaidacea
0 50 100 150 200 250 300 350 400
A1 A3
A4 A5
Hout 1 Hout 2
Hout 4
Hin2 Hin3
Hin4 Hin5
C1 C2
SMN1
R2 R3
R4 R4
Abundance
Diastylidae Bodotriidae Lampropidae Nanastacidae Leuconidae
0 500 1000 1500 2000 2500 3000 3500 4000
A1 A2
A3 A4
A5
H-out1 H-out2
H-out4
H-in2 H-in3
Hin4 H-in5
C1 C2
SMN1
R2 R3
R4
Abundance
Cumacea Amphipoda Isopoda Mysidacea Tanaidacea
-2 [10 m]
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
A1 A3
A4 A5
Hout 1 Hout 2
Hout 4
Hin2 Hin3
Hin4 Hin5
C1 C2
SMN1
R2 R3
R4 R4
RelativeAbundance
Diastylidae Bodotriidae Lampropidae Nanastacidae Leuconidae
-2 [10 m]
A H C R
SMN
A Cape Adare H Cape Hallett
C Coulman Island R Cape Russell
SMN Santa Maria Nove
78°
76°
74°
I
II
160° 170° 180°
Distribution of the cumacean families:
Leuconidae (8-85%), Nanastacidae (10-92), Dyastilidae (3-16%), Lampropidae (<1-2%) and Bodotriidae (<1%)
Out of 29 collected species 21 were new to the Ross Sea
The number of species recorded for the Ross increased from 12 to 33
