Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 17. Of the volumes currently available in the Antarctic Research Series, this volume is the fourth dealing with the biology of the antarctic seas. These collected papers comprise the results of original investigations, 11 of which are concerned mainly with the identification and distribution of marine plants and animals. In the first of these papers Stewart Springer gives a systematic appraisal of the five species of elasmobranch Rajidae from Antarctica, of which one represents a new and unique species. Heretofore one of the peculiarities of the antarctic ichthyological fauna has been the absence of sharks. In this very significant contribution, the author establishes the most southerly record for any member of the elasmobranchs. The second paper, by Patricia Kott, amplifies our systematic knowledge of the tunicates of the South Atlantic, South Pacific, and Indian oceans. It extends her monograph published as volume 13 of the Research Series under the title of Antarctic Ascidiacea and is based on collections made in the Antarctic through 1967; two new species are included. Additions and corrections to volume 13 are appended to this paper. John C. Markham reports on several lower chordates of the genus Cephalodiscus and discusses the systematics and distribution of the five species known from the Antarctic. The Deep Freeze materials examined in the course of this study were obtained through the U.S. Navy Hydrographic Office oceanographers from icebreakers assigned to task force 43 prior to and after the 1955–1959 International Geophysical Year and precede the National Science Foundation sponsored research now being conducted by the USNS Eltanin and the R/V Hero under the U.S. Antarctic Research Program.

During the intensification of research activities in the Southern Ocean in recent years, both at national levels and through international cooperation in such projects as BIOMASS with its FIBEX and SIBEX phases, the need was felt increasingly for closer collaboration between biologists, meteorologists, and oceanographers in the study of the interaction between the atmospheric forces, the water masses, and the living resources. Better knowledge in this regard is not only of scientific interest but also of practical importance, especially for the management of the resources and the protection of the Antarctic marine ecosystem. As a follow-up on a recommendation by the IOC Program Group for the Southern Oceans made in March 1983, the Intergovernmental Oceanographic Commission organized a meeting of experts on oceanography related to the dynamics of the Antarctic ecosystems. During this meeting, held in Kiel, Federal Republic of Ger many, in May 1984, biologists and oceanographers involved in BIOMASS activities met with the oceanographers of SCOR Working Group 74 to discuss ways and means for additional physical and chemical observations in the oceanographic research within BIOMASS. It was the time when large fluctuations in the distribution of krill with subsequent detrimental effects on predator species dependent on krill had just been observed, and the question arose whether this was possibly the result of changes in the Antarctic water circulation.

Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 49. The distribution of Siphonophora of the Antarctic, Subantarctic, and adjacent regions of the Pacific and Atlantic Oceans is described. Specimens for this study were obtained during the United States Antarctic Research Program from USNS Eltanin cruises 3-5, 8-23, 25-28, 35, and 38 during spring, summer, fall, and winter. Samples were collected from 1962 to 1969, using open-closing and nonclosing plankton nets. Information is compiled on horizontal distributions of siphonophores in the South Atlantic Ocean west of 0°. Illustrations of the species, and maps of distribution at the three bathymetric levels, are also included. In addition, data on Eltanin cruise 30 are presented, covering mainly the Pacific tropical region during the summer, with some stations below the equator (austral winter). Vertical distributions of each species are discussed for the three bathymetric zones: epipelagic (200-0 m), mesopelagic (1000-200 m), and bathypelagic (below 1000 m). Life stages and seasonal variations are also considered. Eighty species of Siphonophora were identified in these collections. Among these, and described elsewhere, were five new species: Lensia eltanin, L. eugenioi, L. landrumae, Heteropyramis alcala, and Thalassophyes ferrarii. The eudoxid stages of L. lelouveteau and L. reticulata were also discovered. In addition, the following rare Siphonophora species were collected: Halistemma cupulifera, Desmophyes annectens, Lilyopsis rosea, Eudoxia macra, Lensia achilles, L. baryi, L. exeter, L. grimaldii, L. hostile, Nectocarmen antonioi, and Clausophyes galeata. The most common species of the Antarctic Subantarctic region during the four seasons was Dimophyes arctica. The eudoxid stages of Chelophyes appendiculata, Diphyes dispar, Diphyopsis mitra, Clausophyes ovata, and Heteropyramis maculata were abundant.

Antarctica, a vast land remote from the other continents and still the least known of them all, provides a unique international laboratory for science. Despite the costs, a growing number of countries are supporting basic scientific research on the continent and in its surrounding seas. Our knowledge of life in this extreme environment, although limited, suggests that it is a key environment for many areas of science. Potential economic developments for food and minerals as well as increasing political complications might jeopardise the present scientific accord in the future. Now is the time to take stock: what do we know about Antarctic ecology? What are the threats and how can they be met? In this volume Antarctic scientists from six countries write about the Antarctic ecosystem.

Biology of Antarctic Fish presents the most recent findings on the biology of fish in the unique environment of the Antarctic ocean. At present the year-round temperature of the coastal waters is very near -1,87 ° C, the equilibrium temperature of the ice-seawater mixture. This extremely low temperature affects different levels of organization of fish life: individuals, organ systems, cells, organelles, membranes, and molecules. Exploring ecology, evolution, and life history as well as physiology, biochemistry, and molecular biology of Antarctic fish the book describes the mechanisms of cold adaptation at all these levels. It provides material for discussion also for fundamental questions in the field of adaptation to an extreme environment and therefore is of particular interest not only to specialized scientists, but also to those involved in basic and evolutionary biology.

Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 73. The 4 million to 20 million square kilometers of sea ice that surrounds the Antarctic continent represents one of the largest and most dynamic ecosystems on Earth. This sea ice matrix provides a habitat for a wide variety of organisms, some of which live their entire lives within the ice while others are only occasional visitors. Large grazers, such as copepods and krill which come to the sea ice to feed, represent important links between sea ice biota and the pelagic environment. Unfortunately, because of the inherent difficulty of sampling such an environment, many aspects of this unique habitat are still poorly understood. The purpose of this volume is to present new information about this ecosystem so that its role within the Antarctic food-web (and as a sink for carbon dioxide) and its susceptibility to environmental changes can be better understood.