Macrobenthos Distribution in the Laptev Sea in Relation to
Hydrology
V.V. Petryashov 1 , B.I. Sirenko 1 , A.A. Golikov 1 , A.V. Novozhilov 2 , E. Rachor3,
D. Piepenburg 4 and M.K. Schmid 4
(1) Zoological Institute, Russian Academy of Sciences, 1 Universitetskaya, 199034 St. Petersburg, Russia
(2) State Research Centre - Arctic and Antarctic Research Institute, 38 Bering St., 199226 St. Petersburfi,
Russia
(3) Alfred- Wefiener-Institut fur Polar- und Meeresforschung, Postfach 120161, D 27515 Bremerhavell,
Germany
(4) Institut jur Polarokolofiie, Universitiit Kiel, Wischhofstrasse 1-3, D 24148 Kiel. Germany
Received 3 March 1997 and accepted in revised form 5 December 1997
Abstract - As a results of six joint expeditions to the Laptev Sea in 1993, 1994 and 1995,
150 invertebrate species were added to the list of species known from this high-Arctic
region, comprising now 1235 species in total. Most of these species (987) are
macrozoobenthic. The geographic distribution of macrobenthic species numbers and
biomass exhibited a pronounced increase to the north up to 77°N. In terms of biogeographic
composition, Boreal-Arctic species accounted for most of the species, primarily widespread
Boreal-Arctic species in the southern and central Laptev Sea at depths from 10 to 75 m and
primarily Atlantic Boreal-Arctic species in the northern Laptev Sea at depths of 90 to 1100
m. Only in depths of more than 2000 m, as well as in estuarine and brackish coastal
waters, Arctic forms had significant species shares. On sandy and silty bottoms, nine major
communities and two trophic zones were distinguished. The distribution of species
numbers, biomass and faunal composition is discussed in relation to water depth, seabed
sedimentology and near-bottom water salinities. The latter are supposed to be the major
environmental factor regulating the distribution and structure of macrobenthic communities.
An ecological-biogeographical zonation scheme is proposed, combining the current
information about the distribution of macrobenthic communities and brackish water
masses.
Introduction
The Laptev Sea, which occupies a central position among the Eurasian seas, is of particular
scientific interest owing to its unique features. For instance, it is the only Eurasian sea which
includes large deep-sea basins with depths of more than 3000 m. Moreover, the Gakkel Ridge,
which is the continuation of the mid-Atlantic ridge, meets the continental slope of the Laptev
Sea. The hydrography is characterized by pronounced thermohaline gradients, caused by the
massive inflow of riverine waters in summer, and by a diverse ice regime with quasi-stationary
polynyas in winter. Large water masses of Atlantic and Pacific origin do apparently not
penetrate directly into the southern and central epicontinental parts of the Laptev Sea.
The fact that the Laptev Sea is difficult to reach from both east and west, as well as its
rigorous ice conditions, account for the insufficient knowledge about it. It was not until the last
few years that it became possible to conduct several expeditions of Russian and German
research vessels to this remote Arctic region (RV "Ivan Kireev" in 1993; ice-breaking RV
"Polarstern" in 1993 and 1995; RV "Professor Multanovsky" in 1994; icebreaker "Kapitan
Dranitsyn" and RV "lakov Smirnitsky" in 1995).
Rich benthological material collected from grab samples and dredge catches during these
expeditions (Table 1) permitted us not only to improve the previous knowledge on species
diversity in the Laptev Sea, but also to obtain new information on benthos distribution (Rachor
et aI., 1994; Anisimova et a!., 1997; Piepenburg and Schmid, 1997). The present paper aims to
synoptically summarize the results of these investigations.
In: Kassens, H., H.A. Bauch, I. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, \999, \69-\80.
Hydrology
V.V. Petryashov 1 , B.I. Sirenko 1 , A.A. Golikov 1 , A.V. Novozhilov 2 , E. Rachor3,
D. Piepenburg 4 and M.K. Schmid 4
(1) Zoological Institute, Russian Academy of Sciences, 1 Universitetskaya, 199034 St. Petersburg, Russia
(2) State Research Centre - Arctic and Antarctic Research Institute, 38 Bering St., 199226 St. Petersburfi,
Russia
(3) Alfred- Wefiener-Institut fur Polar- und Meeresforschung, Postfach 120161, D 27515 Bremerhavell,
Germany
(4) Institut jur Polarokolofiie, Universitiit Kiel, Wischhofstrasse 1-3, D 24148 Kiel. Germany
Received 3 March 1997 and accepted in revised form 5 December 1997
Abstract - As a results of six joint expeditions to the Laptev Sea in 1993, 1994 and 1995,
150 invertebrate species were added to the list of species known from this high-Arctic
region, comprising now 1235 species in total. Most of these species (987) are
macrozoobenthic. The geographic distribution of macrobenthic species numbers and
biomass exhibited a pronounced increase to the north up to 77°N. In terms of biogeographic
composition, Boreal-Arctic species accounted for most of the species, primarily widespread
Boreal-Arctic species in the southern and central Laptev Sea at depths from 10 to 75 m and
primarily Atlantic Boreal-Arctic species in the northern Laptev Sea at depths of 90 to 1100
m. Only in depths of more than 2000 m, as well as in estuarine and brackish coastal
waters, Arctic forms had significant species shares. On sandy and silty bottoms, nine major
communities and two trophic zones were distinguished. The distribution of species
numbers, biomass and faunal composition is discussed in relation to water depth, seabed
sedimentology and near-bottom water salinities. The latter are supposed to be the major
environmental factor regulating the distribution and structure of macrobenthic communities.
An ecological-biogeographical zonation scheme is proposed, combining the current
information about the distribution of macrobenthic communities and brackish water
masses.
Introduction
The Laptev Sea, which occupies a central position among the Eurasian seas, is of particular
scientific interest owing to its unique features. For instance, it is the only Eurasian sea which
includes large deep-sea basins with depths of more than 3000 m. Moreover, the Gakkel Ridge,
which is the continuation of the mid-Atlantic ridge, meets the continental slope of the Laptev
Sea. The hydrography is characterized by pronounced thermohaline gradients, caused by the
massive inflow of riverine waters in summer, and by a diverse ice regime with quasi-stationary
polynyas in winter. Large water masses of Atlantic and Pacific origin do apparently not
penetrate directly into the southern and central epicontinental parts of the Laptev Sea.
The fact that the Laptev Sea is difficult to reach from both east and west, as well as its
rigorous ice conditions, account for the insufficient knowledge about it. It was not until the last
few years that it became possible to conduct several expeditions of Russian and German
research vessels to this remote Arctic region (RV "Ivan Kireev" in 1993; ice-breaking RV
"Polarstern" in 1993 and 1995; RV "Professor Multanovsky" in 1994; icebreaker "Kapitan
Dranitsyn" and RV "lakov Smirnitsky" in 1995).
Rich benthological material collected from grab samples and dredge catches during these
expeditions (Table 1) permitted us not only to improve the previous knowledge on species
diversity in the Laptev Sea, but also to obtain new information on benthos distribution (Rachor
et aI., 1994; Anisimova et a!., 1997; Piepenburg and Schmid, 1997). The present paper aims to
synoptically summarize the results of these investigations.
In: Kassens, H., H.A. Bauch, I. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, 1. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, \999, \69-\80.