Concluding Commentary

It is apparent that remoteness and isolation have not insulated the New Zealand Sector of the Southern Ocean and adjacent shores from mankind's contaminants. On the other hand, it is an emotional overstatement to suggest the region is now becoming befouled (see Joyner, 1985, p. 169). Certainly, the shores of New Zealand's Subantarctic islands no longer have quite the unsullied and pristine character savoured by Guthrie-Smith (1936) but they can in no way be considered significantly polluted....

Introduction

For centuries, the world's oceans were viewed as a vast sink into which one could cast waste of any kind. In the past couple of decades, however, there has been a growing awareness that the oceans do not possess an infinite capacity to absorb the wastes of modern industrial society. Whilst there is some general consensus that the 'health' of northern hemisphere seas, and particularly inshore waters adjacent to heavily populated and industrialized regions, has been progressively deteriorating,...

Conclusions

This survey of ice in the Antarctic Sector of the Pacific has shown that the diverse ice forms there are understood in general terms. Their distribution and other characteristics are complex and very significant in environmental and human terms. However, important information on physical process is still lacking. More data on the mass balance and flow of the Ross Ice Shelf and the major glaciers in Pine Island Bay are needed so that the ice sheets response to global change, for example the...

Key To Species

The effect of the Polar Front on the distribution of seabirds in the Antarctic Sector of the Pacific (Eltanin Cruises 20 and 21,1966, see text). Note the effect of a sharp-zoned Polar Front on the Thin-billed Prion (11) and how, despite its intensity, the Polar Front can effectively halt species such as the Wandering Albatross. general southward drift of the surface layer, and the krill's power of locomotion would scarcely allow for one mile a day even if it moved continuously in one...

Summary

Its polar glacial setting, sea ice cover, and great depth combine to make the Antarctic continental shelf a unique sedimentary environment. A myriad of glacial settings occurs along the Pacific Sector of the Antarctic continental margin, which extends from the Antarctic Peninsula to the Ross Sea. These range from vast ice shelves, the largest being the Ross Ice Shelf, to mountainous coasts where valley glaciers flow into the sea. The Ross Sea continental shelf is the most thoroughly studied...

Significance Of Nanoplankton And Picoplankton

In contrast to phytoplankton larger than 35 Jim in size (net phytoplankton), which in the past have received considerable attention and form the basis of the classic food chain, the contribution of nanoplankton (< 20 jm) to the standing crop and primary production has been overlooked until recently (Pomeroy, 1974). Fay (1973) was the first to show that nanoplankton contribute about 70 of phytoplankton biomass and primary production of the Ross Sea. El-Sayed and Taguchi (1981) reported on the...

Exploration And Exploitation

There is considerable offshore petroleum potential for areas to the south and southeast of New Zealand (Katz, 1974 Cook and Davey, this volume). Explora tory drilling in the Great South Basin east and southeast of Stewart Island and Solander Basin immediately to the west has proved promising but exploitable hydrocabon accumulations await discovery (Sanford, 1980). Management plans prepared for The Snares, Campbell and Auckland Islands (Department of Lands and Survey, 1983, 1984, 1987)...

Info

ALBATROSSES, MOLLYMAWKS and PETRELS Wandering Albatross Grey-headed Mollymawk Buller's Mollymawk White-capped Mollymawk Light-mantled Sooty Albatross Antarctic Petrel Antarctic Fulmar Southern Giant Petrel Northern Giant Petrel Cape Pigeon Snow Petrel White-headed Petrel Mottled Petrel

Table

W Wave development - localized thickening of a cloud band. A Early vortex development - comma cloud merged with a major cloud band B Late vortex development - a hook-shaped cloud with a marked slot of clear C Vortex at full maturity - spiral of clear air around a well-defined centre. D Dissipating vortex - either Dx with considerable cloud near centre, or Dy F G Frontless vortices (or cut-off lows) - corresponding respectively to Dx and Dy types but not...

The Antarctic Ice Sheet

The Antarctic ice sheet has the form of two coalesced ice sheets and is basically dome shaped (Fig. 4.1). The larger thicker East Antarctic Ice Sheet is classed as terrestrial because its base is resting on land which is mostly above sea level. (The mean elevation of bedrock in East Antarctica is 15 m, Drewry et al. 1982). The smaller, lower elevation West Antarctic Ice Sheet is a marine ice sheet because it is grounded mostly well below sea level (Fig. 4.1 inset). The mean elevation of bedrock...

Composition

The copepods constitute the bulk of the Antarctic mesoplankton (middle-sized zooplankton), accounting for an average of about 70 of its total biomass (Fig. 8.14) The three most prevalent species are Calanoides acutus, Calanus propinquus, and Rhincalanus gigas. Hopkins (1971) contended that the principal contributors to zooplankton biomass in samples taken in the Pacific Sector of the Southern Ocean are the copepods, chaetognaths and euphausiids, in that order. He found that the copepods...

Origins

Although the Antarctic Sector of the Pacific appears little more than a windswept ocean with places of ornithological interest restricted to its periphery, it was not always so. The region was probably the cradle from which the early penguin petrel stock began its evolutionary growth and diversification in the late Cretaceous and early Tertiary. That the penguins (Sphenisciformes) and the petrels (Procellariiformes) originated in the Late Cretaceous seems clear since none of the region's...

Ft AMERPA

The southeastern Pacific Ocean showing magnetic lineations (after Cande et al., 1982) with anomaly numbers after Heirtzler et al. (1968). Spreading ridges shown by heavy solid lines. Fracture zones are marked by dotted lines. Inactive plate boundaries by cross lines. 2,000 m bathymetry contours marked by dashed line (Mercator projection). Aluk Ridge has been subducted under West Antarctica (Fig. 5.8). When this spreading centre, between the Tula Fracture Zone and Peter I Island,...

Distribution

The circumpolar distribution of krill seems to be lopsided there are large populations in the Atlantic Sector of the Antarctic, and thinner bands around the rest of the continent (Fig. 8.16). Whether these areas of high krill concentration represent separate stocks is not at present known. However, this is an issue of crucial importance to the way the krill resource is to be managed (Laws, 1985b). Krill have a strongly aggregated distribution. The average krill patch size Fig. 8.15. Krill...

J

F'M'A'M'JJ1 A 1 S 1 O 1 N 1 D 1 Month Fig. 2.4. Monthly mean zonally-averaged pressure difference (in hPa) between 40 S and 60 S. Based on daily numerical analyses by the Australian Bureau of Meteorology over the 5-year period 1972-77 (after Streten, 1980). Fig. 2.4. Monthly mean zonally-averaged pressure difference (in hPa) between 40 S and 60 S. Based on daily numerical analyses by the Australian Bureau of Meteorology over the 5-year period 1972-77 (after Streten, 1980). maximum and minimum...

Sea

Sea ice is frozen sea water and in the Antarctic is mostly mobile pack ice less than one year old. When the sea surface begins to freeze, from about mid February on, small needles or platelets of ice appear, growing and agglomerating to form a slush known as grease ice. As it thickens, this slush coagulates and breaks up under the influence of waves and wind into intermediate soft and hard plates which collide with each other and may form pancake ice. Still thickening, these alternately freeze...

Confined To New Zealand Province

Royal Penguin Yellow-eyed Penguin Snares Crested Penguin Erect-crested Penguin Chatham Is Blue Penguin Northern Royal Albatross Southern Royal Albatross NZ Black-browed Mollymawk Southern Bullers Mollymawk Northern Bullers Mollymawk Shy Mollymawk Salvins Mollymawk Chatham Is Mollymawk Snares Cape Pigeon Fulmar Prion Mottled Petrel Chatham Is Taiko Chatham Is Petrel Black-winged Petrel White-faced Storm Petrel Southern Diving Petrel Bounty Is Shag Campbell Is Shag Pitt Is Shag Red-billed Gull...

Os Vo

These waters have salinities greater than 34.5 o while in northern Drake Passage the salinities are less than 34.1 o. The relatively low salinity surface waters in northern Drake Passage originate in the southeastern Pacific along the southern coast of Chile (Silva and Neshyba, 1979 80), a region of heavy precipitation and continental runoff. This region may also be the source for the extensive tongue of low salinity surface water that extends westward from the South American continent between...

Contents

Environmental considerations 19 Atmospheric circulation over the Southern Ocean 26 Interaction between sea ice and atmospheric circulation in the Southern Ocean 42 Effect of the Antarctic continent on atmospheric circulation Present research efforts and problems for the future 50 Mean wind forcing and large-scale oceanic response 57 Mean current structure and interaction with bottom topography 59 Water masses and thermohaline circulation 76 Ice shelves and other marine glaciers 100 Plate...

Foraging Behaviour And Food

What seabirds eat and how they obtain their food has, until recently, been one of the least studied aspects of Antarctic bird ecology (Ashmole, 1971 Ainley, 1977 Croxall and Prince, 1980 Croxall, 1984 Harper etal., 1985 Schramm, 1986 Harper, 1987). Croxall (1984) reviewed the feeding methods of seabirds and gave examples of feeding techniques based upon the terminology of Ashmole (1971) and the morphology of bill structure. Although some species scavenge food from ships and fishing vessels,...

Distribution At

The distribution of birds at sea is a complex issue made more difficult by our limited understanding of what controls it. Distributional studies are, at the very least, reliant upon comprehensive oceanographic data being available and understandable to the ornithologist at sea. Sadly, this is often not the case. As Brown (1980) has noted, an appreciation by ornithologists that the ocean is not merely a wet provider of food but is in fact a myriad of patches and pathways affected by water...

Standing Crop

Despite the extensive zooplankton investigations carried out in the Southern Ocean, it is difficult to arrive at reasonable estimates of the zooplankton standing crop in Antarctic waters because of problems related to sampling techniques, patchy distribution, and seasonal vertical migration. It is usually assumed, however, that the biomass of zooplankton, in general, is the same as that of krill. The total biomass of zooplankton in the upper 1,000 m in the Pacific Sector averages 3.50, 2.55,...

Breeding And Spawning Of Krill

Breeding takes place in at least four areas the Bellingshausen Sea, the Brans-field Strait, Davis Strait, and in the vicinity of South Georgia Island. We do not know whether there is a main breeding area in the Pacific Sector or how many breeding stocks there are. A female krill produces from as few as 500 eggs to as many as 8,000 eggs (average of 2,500) per brood with a brood interval of 6.5 days. The spawning season lasts two months, yielding an annual egg production of 22,000 eggs per season...

List Of Contributors

Department of Geology, Rice University P.O. Box 1892, Houston, Texas 77251, U.S.A. National Museum of New Zealand Private Bag, Wellington, New Zealand P.O. Box 30-368, Lower H tt, New Zealand P.O. Box 1320, Wellington, New Zealand Department of Oceanography, Texas A& M University, College Station Texas 77843-3146, U.S.A. N.Z. Oceanographic Institute, Division of Water Sciences, DSIR Private Bag, Kilbirnie, Wellington, New Zealand Department of Geology, University of Auckland Private Bag,...

Dependency

Precipitous cliffs, like these in Cenozoic volcanic breccias south of Cape Adare, North Victoria Land, would self cleanse rapidly even when not protected by ice. Fig. 11.13. Frequency bar graph illustrating proportions of each coastal type for the region shown in Fig. 11.12. Seasonal, ice-free shores are far more common in this region than they are for most of the continent with the exception of the Antarctic Peninsula region. Fig. 11.14. Precipitous cliffs, like these in Cenozoic...

Krill Exploitation

Concern over the need for proper management and conservation of Antarctic krill (and other living resources as well) has been voiced by members of the scientific community and by international organizations. The former's concern stems from the lack of adequate information on a host of questions concerning krill growth rates, rate of advance to maturity, longevity, fecundity and spawning events, and the temporal and spatial differences within the populations throughout their circumpolar range....

The Future

With the cessation of commercial whaling and sealing in the Antarctic Sector of the Pacific, one is tempted to say there cannot now be any serious threat to the survival of the animals in that isolated region. Indeed, we have seen that for some marine mammals the signs are encouraging the populations are increasing rapidly (fur seals) or slowly (blue whales), and there are substantial numbers of other species still present (sperm whales, crabeater and Weddell seals). There are, however, some...

Table 113

Environmental factors affecting hydrocarbon exploration and exploitation in the Ross Sea (from Holdgate and Tinker, 1979 additions from Zumberge, 1982). Factors that Influence Site Selection Geological indications of oil potential Bathymetry and structure of the sea bed Iceberg and pack ice condition and distribution Currents (surface and deep) Climate - weather Special biological features of site (and alternatives) Cost of operation Technological Factors that Influence Impacts Use of seismic...

Key

Partially ice covered low rocky shores. Beaches Fig. 11.12. Simplified map of coastal types for Victoria Land and Ross Island. Note the very limited distribution of beach and low rocky shore categories - environments likely to bear the brunt of any on-shore facility development.

Breeding Distribution

Watson et al. (1971) recognized five zoogeographical provinces in the Antarctic and Subantarctic regions. Of these, three are relevant to the Antarctic Sector of the Pacific the Antarctic Continental Province which encompasses all the area south of the maximum pack ice limit, the New Zealand Province, and the Magellanic District of the Atlantic Province which includes the Chilean coast of South America. The composition of species within these provinces is shown in Table 10.1. Table 10.2...

Plankton Under The Ross Ice Shelf

Until recently, the existence of life in the relatively deep cul-de-sacs beneath the large Antarctic ice shelves was primarily a topic of speculation. Because the thickness of the Ross Ice Shelf (400-500 m) precludes photosynthesis in the underlying water column, it was originally suggested that a sub-ice biota might be absent altogether or that a highly specialized, novel assemblage might exist in which chemosynthesis (formation of organic compounds from inorganic substances using energy...

Transport

Until recently, the best available estimates of the transport of the ACC were based on the density field alone. Such relative transport estimates assume that the current speed approaches zero at great depth. The most consistent transport figures come from regions where the ACC is geographically constrained between Australia-New Zealand and Antarctica and in Drake Passage. The relative transport through Drake Passage is about 115 Sv (1 Sverdrup 106 m3 sec.1) according to Reid and Nowlin (1971)...

Summary And Conclusions

In this chapter, we have presented a general qualitative description of the major water masses and the large-scale features of the mean circulation in the Pacific Sector of the Southern Ocean. The circulation is dominated by the wind-driven eastward flow of the Antarctic Circumpolar Current. In the Southwestern Pacific Basin, this current consists of at least two relatively narrow jets of intense flow associated with sharp horizontal gradients (fronts) in the property field. These jets appear...

Present Research Efforts And Problems For The Future

A comprehensive review of polar processes and their role in the global climate system has recently been given by the Polar Group (1980). They acknowledge that the most pressing problem at the present time is the lack of ground-truth observations (particularly in winter) needed to adjust the numerical models to improve their portrayal of physical processes. To increase the data base in the polar regions, it is important to continue employing drifting buoys and automatic weather stations in the...

Cip

ISBN 0-444-88510-2 (Vol. 51) Elsevier Science Publishers B.V., 1990 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher, Elsevier Science Publishers B.V. Physical Sciences & Engineering Division, P.O. Box 330, 1000 AH Amsterdam, The Netherlands. Special regulations for readers in the USA -...

Marine Living Resources

Whilst the Antarctic terrestrial ecosystem has an extremely low productivity with a total production of plant material measured in the hundreds of tonnes per year, the Southern Ocean south of the Antarctic Convergence has a very much higher productivity with a total plant (phytoplankton) production measured in thousands of millions of tonnes per year. However, the overall productivity of the Southern Ocean is not as high as previously believed (El-Sayed and Turner, 1977 Holm-Hansen et al., 1977...

I

Mapa San Andres Tuxtla Con Nombre

Jurassic Volcantes Pre-Cretaceous strata (Swanson Group) Palaeozoic intrusivos high grade metamorphics (Fosdick Group) Fig. 5.13. Geology of Marie Byrd Land. Bathymetry contours at 500 m and 3,000 m (where available) delineate continental slope and shelf (Polar Stereographic projection). indicate the shelf may reach 400 km in width in Amundsen Sea. About 4-5 km of sedimentary cover of Cretaceous or younger age (Fig. 5.12) probably built out as a prograded shelf under the upper continental rise...

Western Antarctic Peninsula And Western Ellsworth Land

Few data exist over the continental margin of Antarctica between the Ross Sea and Thurston Island. Further to the east, geophysical data over the upper continental rise and shelf are confined to detailed studies in the northern Antarctic Peninsula region (e.g., Ashcroft, 1972) and to widely spaced profiles (Houtz, 1974 Tucholke and Houtz, 1976) including multichannel seismic data (Kimura, 1982) across the continental margin between Anvers Island and Thurston Island (Fig. 6.7). The continental...

Subantarctic Front Polar Front

Sub Antarctic Climate

DS OS DS E43 I-1-EI7-1E33 TH GL Fig. 3.6b. Distribution of salinity ( o) on the section. Dotted line indicates the core of the subsurface salinity minimum. Fig. 3.6c. Distribution of dissolved oxygen (ml 1) on the section. Fig. 3.6c. Distribution of dissolved oxygen (ml 1) on the section.

Mw Holdgate

There is a contradiction in the title of this book. For most volumes about the Southern Ocean stress its circumpolar continuity. The West Wind Drift sweeps around the earth, south of the inhabited southern continents. The main hydro-logical features of the Pacific Ocean the East Wind Drift at its southern margin, spilling into the Ross Gyre the westerly current further north the northward movement of cold, dense bottom water and of the less saline surface waters with their burden of floating...

Mean Wind Forcing And Largescale Oceanic Response

Although detailed knowledge of the wind fields over the southern hemisphere at any particular time is limited by a chronic shortage of observations over large, remote areas of the ocean, the major climatological features of these fields have been fairly well documented (e.g., Taljaard et al., 1969 Jenne et al. ,1971 Han and Lee, 1981). The climatological sea-level pressure distribution is dominated by subtropical highs centred over the oceans at approximately 30 S, low pressure cells around the...

References

Aagaard, K., Roach, A.T. and Schumacher, J.D., 1985. On the wind-driven variability of the flow through Bering Strait. J. Geophys. Res., 90 7213-7221. Abarnou, A., Robineau, D. and Michel, P., 1986. Contamination par les organo-chlor s des dauphins de Commerson des les Kerguelen. Oceanol. Acta, 9 19-29. Abrams, R.W., 1985. Energy and food requirements of pelagic aerial seabirds in different regions of the African Sector of the Southern Ocean. In W.R. Siegfried, P.R. Condy, and R.M. Laws...

Other Marine Glaciers

The ice front of three other ice shelves in the Pacific Sector have retreated in recent years. The fronts of the Wordie and George VI Ice Shelves on the west coast of the Antarctic Peninsula have retreated by several kilometres over the last 10 to 30 years (Doake, 1982). About one-third of the Wordie Ice Shelf has disappeared. This behaviour may be due to a warmer climate and decreasing snowfall in recent years, although glaciers in parts of the Peninsula are still thickening apparently in...

Table 112

Seabirds of the New Zealand region of the Southern Ocean known to ingest plastic particles (sources Jehl et al., 1980 Reed, 1981 Bourne and Imber, 1982 Furness, 1983, 1985 Randall et al., 1983 Day et al 1985 Brown et al., 1986 Skira, 1986 Harper and Fowler, 1987 Ryan, 1987b, c Ryan and Jackson, 1987). Blue Penguin ( ) Rockhopper Penguin Adelie Penguin ( ) Wandering Albatross Southern Royal Albatross Salvin's Mollymawk Black-browed Mollymawk Grey-headed Mollymawk Yellow-nosed Mollymawk Sooty...

Shared With Magellanic District

Sen and Bellingshausen Seas has been little studied, largely because of the vast and impenetrable pack ice that dominates this region. Adelie Penguins, Snow Petrels and Antarctic Skuas are known to breed in Marie Byrd Land (information reviewed in Harper et al., 1984). Recently, Broady et al. (1989) reported 10,000 nests of Antarctic Petrels on Edward VII Peninsula. Peter I Island, the only oceanic island in the southeastern part of the region, is reported to have a few breeding Adelie and...

Marine Manganese Deposits

KAMENKOVICH FUNDAMENTALS OF OCEAN DYNAMICS 17 R.A. GEYER SUBMERSIBLES AND THEIR USE IN OCEANOGRAPHY AND OCEAN ENGINEERING 18 J.W. CARUTHERS FUNDAMENTALS OF MARINE ACOUSTICS 19 J.C.J. NIHOUL (Editor) BOTTOM TURBULENCE 20 P.H. LEBLOND and L.A. MYSAK WAVES IN THE OCEAN 21 C.C. VON DER BORCH (Editor) SYNTHESIS OF DEEP-SEA DRILLING RESULTS IN THE INDIAN OCEAN 23 J.C.J. NIHOUL (Editor) HYDRODYNAMICS OF ESTUARIES AND FJORDS 24 F.T.BANNER, M.B.COLLINS and K.S. MASSIE (Editors) THE NORTH-WEST...

Distribution And Sources

The amounts of seaborne plastic and other persistent synthetic litter being cast up on the larger Subantarctic islands are greatest on windward (western) shores such as North West Bay, Campbell Island, and Derry Castle Reef, Enderby Island, and least on leeward (eastern) shores (cf. Gregory, 1987). This same pattern is also evident around the semi-enclosed waters of Port Ross, Auckland Islands. Few littering items appear on the protected south facing sandy beach of Enderby Island. Across the...

Concluding Remarks

From the preceding discussion, it can be seen that there has been a very substantial increase in our knowledge of the Antarctic Sector of the Pacific in many scientific disciplines, particularly since the IGY. Nonetheless, much of this remains in specialist journals and is not readily available. Further, the question of the possible exploitation of Antarctic resources has brought Antarctica and its surrounding oceans into increasing prominence over the last few years. It is also seen that the...

Food And Feeding

Until recently, krill have been considered to be exclusively herbivorous and, therefore, primary consumers in the ecosystem. Winter feeding and growth have been considered to be negligible since phytoplankton productivity decreases due to the extensive ice cover in the seas adjacent to the Antarctic. However, during 12 months of laboratory experiments with krill, carnivorous, detritivorous, and cannibalistic feeding were demonstrated (McWhinnie and Denys, 1978). Kott-meier and Sullivan (pers....

Continental Margin Sedimentation

Sedimentation The Coastline

The Antarctic Sector of the Pacific is bounded on the south by the Antarctic continent, which is the primary source of terrigenous sediment to this region. For this reason, sedimentation on the Antarctic continental margin is discussed in some detail. The Antarctic continental shelf is unique compared to other continental shelves of the world for the following reasons (1) glaciers flow directly into the sea so that sediment supply is by ice surface meltwater runoff is presently minimal (2) it...

Krill

As a result of the extensive collections made during the Discovery II investigations in the 1920s and 1930s, almost all that is known about krill comes from the classic studies of the late J.W.S. Marr during that expedition (Marr, 1962). Of the 11 species of Antarctic krill, interest centres around Euphausia superba, E. crystal-lorophias, Thysanoessa macrura, and . valentini. These euphausiids are located as follows E. valentini is found north of the Polar Front E. crystallorophias inhabits the...

Bird Densities At

Attempts to understand the relationship between oceanic birds and their prey at sea have been hastened by the need for information on human krill harvesting (Knox, 1984) and possible oil and mineral exploitation in the Ross Sea and other basins adjacent to Antarctica. One facet of this endeavour is to obtain an index of seabird biomass. With hindsight, it was inevitable that field observers might adopt their own approach to counting birds at sea. This made comparative analyses extremely...

Note Added In Press

Since preparing this review, there has been a significant diesel oil spill in waters adjacent to the Antarctic Peninsula. In late January 1989, the Argentinian vessel Bahia Para so sank after grounding on shoals off southwestern Anvers Island, a short distance from Palmer Station (U.S.A.). Soon after, in February, the Peruvian vessel Humbolt was refloated after running aground off King George Island some 400 km to the north. The Bahia Paraiso was carrying almost one million litres of diesel as...

Icebergs

Icebergs are masses of ice that have broken away from marine glaciers. They have a wide variety of shapes and sizes, depending on source and decay process and they may be floating or grounded on the seafloor. By definition, icebergs show more than 5 m of ice above sea level and are 100 m2 or more in area. The longest iceberg ever recorded was about 180 km long (Wordie and Kempe, 1933). Its mass would have been about 1012 tonnes. The median width of all Antarctic icebergs is probably less than...

Taxonomy

Post-Pleistocene differentiation is less marked in the penguins than in the petrels. Of 13 penguin species resident in this region, only the Macaroni (Royal) Penguin (Eudyptes chrysolophus ) has a well defined subspecies, schlegeli, which breeds at Macquarie Island. In contrast, subspeciation in the endemic South Pacific forms of the albatrosses (Diomedeidae) has been strong. Some full species are clearly masquerading as subspecies in the present taxonomy. Needing revision are the Southern and...

Seabirds

TAYLOR INTRODUCTION Limiting factors influencing the distibution of seabirds in the Antarctic Sector of the Pacific include the paucity of islands where birds can breed and the lack of a reliable food supply in the region. This lack of food arises because there are few continental margins not covered by pack ice where deep nutrient-rich water can upwell to provide a consistent source for zooplankton on which oceanic birds prey. The main body of the southern...

Seasonal Variations

Several investigators have shown that there is a seasonal change in the vertical distribution of several species (e.g., Sagitta gazellae, Euphausia superba, and Calanoides acutus) in Antarctic waters specimens occur in the upper levels in summer and descend to deep water in winter. Hopkins (1971) noted that over half of the zooplankton biomass of the upper 1,000 m of sampled waters occurred in the top 250 m in late spring, summer, and early autumn months (November through April) while during...

Base Installations

Other than inland stations, permanent and seasonal or temporary bases are preferentially situated on snow- and ice-free reasonably level areas close to the sea. Such places are almost invariably occupied by bird colonies and or plant communities (e.g., Capes Adare, Hallett, Bird, Royds and Evans), and displacement of the original colonists as well as some other environmental interference is inevitable (e.g., Johnston, 1971). Around all bases, there is an accumulation of both organic and...

Exploration History

Ontario Sedimentary Basins

The onshore parts of the Gippsland and Taranaki basins have long histories of exploration. Shallow drilling in Taranaki started in 1866 adjacent to seepages (Katz, 1968) and in Gippsland in 1924 after the indications of oil in water wells (Colman, 1976). Significant production took place onshore in both basins before Fig. 6.2. Distribution of the sedimentary basins of the southwestern Pacific during the Upper Cretaceous when the breakup of Gondwana began (after Grindley and Davey, 1982). Basin...

Hms

Seriously damaged and abandoned after colliding with iceberg in dark fog, 24 Dec. 1789. Lost at sea in 1869 May have struck ice. Presumed to have struck an iceberg and sunk near Cape Horn, 1890. Antarctic Sound to Snow Hill Island, Antarctic Peninsula Crushed by pack ice and sunk on 12 Feb. 1903 after being beset for 5 weeks in the north-west Weddell Sea. South Georgia to Sandwich Islands (on tow)

Longevity

The longevity of krill is still a matter of controversy however, there are indications that krill may live for more than four years. The traditional and often misleading method of determining krill age has been to examine the length frequency distribution of catches, regarding peaks in the histrogram as year-classes. Since krill moult and shrink in body size as an overwintering strategy, successive year-classes of mature krill can overlap, obscuring the length-age relationship. This method is...

High Latitude Exploration And Production

There has been much speculation on the hydrocarbon potential of Antarctica (e.g., Wright and Williams, 1974 Ivanhoe, 1980 Mitchell and Tinker, 1980 Cameron, 1981 Apostolescu and Wanneson, 1982 Auburn, 1982 Behrendt, 1983b, in press Bergsager, 1983 Guillaume, 1983 Garrett, 1984 Quilty, 1984, 1987 Tessensohn, 1984, 1986 Aleyeva and Kucheruk, 1985 Cortes, 1985 Shapley, 1985 Davey, 1985 Ivanov, 1985 Roland, 1986 St. John, 1986 Anderson, 1987 Crockett and Clarkson, 1987 Larminie, 1987 Parsons, 1987...

Cloud

NOAA-9 satellite infrared image of the 154 km long iceberg B-9 on 9 November 1987, four weeks after its separation from the eastern front of the Ross Ice Shelf. Several other bergs up to 20 km long that calved at the same time can be seen between B-9 and the ice shelf. These had drifted as far west as Ross Island (approximately 600 km) by March 1988 whereas B-9 was only 150 km west-north-west of its calving site at that time. By May 1988, B-9 was close to the north-eastern boundary of...

Marine Interfaces Ecohydrodynamics

MARTIN (Editors) BIOGEOCHEMICAL PROCESSES AT THE LAND-SEA BOUNDARY 44 I.P. MARTINI (Editor) CANADIAN INLAND SEAS 45 J.C.J. NIHOUL and B.M. JAMART (Editors) THREE-DIMENSIONAL MODELS OF MARINE AND ESTUARIN DYNAMICS 46 J.C.J. NIHOUL and B.M. JAMART (Editors) SMALL-SCALE TURBULENCE AND MIXING IN THE OCEAN 47 M.R. LANDRY and B.M. HICKEY (Editors) COASTAL OCEANOGRAPHY OF WASHINGTON AND OREGON 48 S R. MASSEL HYDRODYNAMICS OF COASTAL ZONES 49 V.C. LAKHAN and A.S. TRENHAILE...

Ice Algae

Hooker (1847) was among the first to report on the association of marine flora with sea ice and the discoloring effect of algal growth on icebergs and pack-ice. He observed, they occurred in such countless myriads, as to stain the Berg and the pack-ice a pale ocherous colour. These brown stains are caused by a community of organisms, principally diatoms, living either in the ice or in the brine pockets of the ice. This group of microflora includes over 50 species of mainly neritic diatoms, some...

Antarctic Euphotic Zone

** Integrated values for the euphotic zone ** Integrated values for the euphotic zone integrated values for the Atlantic Sector are not markedly higher than those for the Pacific (15.94 mg m2 and 12.62 mg m2, respectively El-Sayed, 1968). Caution should be exercised in interpreting these results, however. While a great many of the stations occupied in the Atlantic Sector were located in relatively productive coastal regions, most of the stations occupied in the Pacific Antarctic were in oceanic...

Zonation

The continuous eastward flow of the ACC causes the horizontal distribution of water properties in the Southern Ocean to be relatively uniform in the zonal direction while varying meridionally. In most longitudes, the meridional gradients in water properties are not uniform, but occur in steps. That is, relatively broad zonal bands (zones) characterized by weak horizontal gradients are separated by narrow fronts with sharp gradients (e.g., Gordon and Goldberg, 1970 Gordon and Molinelli, 1982). A...

Mesoscale Variability

Mesoscale Eddy

Although the preceding discussion has attempted to describe the configuration of the mean flow within the Pacific Sector, the currents actually exhibit substantial spatial and temporal variability. In his description of the Polar Front, Mackintosh (1946) noted that it forms twists and loops that may extend as much as 100 miles north or south, and it possibly even forms isolated rings. Since the jets within the ACC extend to great depths, interactions with bottom topography influence the nature...

Plastics And The Subantarctic Islands

Sub Antarctic Climate

A great diversity of discarded plastic and other manufactured objects wash up on the shores of the Subantarctic Islands (Figs 11.2 and 11.3). Plastic crates, con- Fig. 11.1 Aluminum-framed, otter-style neuston net used in surface trawling for pelagic plastics and tar balls suspended over ship's side (a) and streaming away from ship's side (b). The mouth of the frame is 0.4 m x 0.4 m. Fig. 11.1 Aluminum-framed, otter-style neuston net used in surface trawling for pelagic plastics and tar balls...

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Profile A across the Eastern Basin (after Hinz and Block, 1983). Major unconformities are marked with interpreted ages. Profile B across the Central Trough (after Hayes and Davey, 1975). Profile C across the Victoria Land Basin (after Cooper and Davey, 1985). Fig. 5.16. Profile A across the Eastern Basin (after Hinz and Block, 1983). Major unconformities are marked with interpreted ages. Profile B across the Central Trough (after Hayes and Davey, 1975). Profile C across the Victoria...

Water Masses And Thermohaline Circulation

The water column in the deep ocean is stably stratified into several layers which are traditionally identified by extrema (cores) in vertical profiles of temperature, salinity, oxygen or nutrients. The distinguishing characteristics of each core layer reflect the unique properties input at the source region and the subsequent modifications of the water mass within that layer. The conservative properties, such as potential temperature and salinity, are modified only by diffusion and mixing as...

Elsevier

Amsterdam Oxford New York Tokyo 1990 ELSEVIER SCIENCE PUBLISHERS B.V. Sara Burgerhartstraat 25 P.O. Box 211, 10OO AE Amsterdam, The Netherlands Distributors for the United States and Canada ELSEVIER SCIENCE PUBLISHING COMPANY INC. 655, Avenue of the Americas New York, NY 10010, U.S.A. Library of Congress Cata loging-in-Publication Data Antarctic sector of the Pacific edited by G.P. Glasby. p. cm. (Elsevier oceanography series 51) Includes oibliographica references. ISBN 0-444-88510-2 (a 1k....

Trough - Southern Hemisphere

Trough Southern Hemisphere

Seasonal cycle of temperature at 50 S and 65 S (upper curves), and meridional temperature gradient 50 -65 S (lower curve), at the 500 hPa level. Based on station data over a 5-8-year period (after van Loon, 1967). Fig. 2.5. Seasonal cycle of temperature at 50 S and 65 S (upper curves), and meridional temperature gradient 50 -65 S (lower curve), at the 500 hPa level. Based on station data over a 5-8-year period (after van Loon, 1967). advance see for example Fig. 2.11). Air...

Factors Governing Primary Production

The factors governing variability in primary production in Antarctic waters have been discussed by Holm-Hansen et al. (1977) and Fogg (1977), and more recently by El-Sayed (1984,1987) and Sakshaug and Holm-Hansen (1986). A brief account of the factors influencing primary production of the Southern Ocean is given below. It is well known that variations in incoming solar radiation between summer and winter in the Antarctic are extreme. Mean monthly values of radiant energy plotted against UC...

Basins Of The Ross

Geophysical research in the Ross Sea shows that thick sedimentary sequences are present over large areas (Houtz and Davey, 1973 Wong and Christoffel, 1981 Davey et al., 1982, 1983 Hinz and Block, 1983 Sato et al. 1984 Cooper et al., 1987). Drillhole data from the Deep Sea Drilling Project (DSDP) Leg 28 (Hayes et al., 1975a, b), McMurdo Sound Sediment and Tectonic Studies (MSSTS-1) drillhole (Harwood, 1986) and Cenozoic Investigations of Ross Sea (CIROS-l) drillhole (Barrett, 1987) show that the...

Marine Mammals

Krill Diagram

Twenty-seven species of whales and dolphins, and 14 species of seals live in or adjacent to the Antarctic Sector of the Pacific Ocean. Some are permanent residents, other migrate in and out of the region, and a few are itinerants from northern waters. This chapter reviews the occurrence, past exploitation and present status of these southern marine mammal species. Until the late 18th century, marine mammals in the Southern Ocean lived unmolested in large numbers in a productive, yet relatively...

Percentage frequency

Mean distribution of Streten vortex types as a function of latitude, based on satellite photographs over 5 winters 1973-77. Frequencies in each 5-degree latitude band are presented as the percentage of the total for that type over all latitudes. Values in brackets give the total numbers of cyclones for the five years studied (from Carleton, 1979). The overall picture then is one of extra-tropical cyclones originating in the middle latitude westerlies and moving gradually southward as...

Minerals

The honour of being the first to suggest possible economic mineral deposits in Antarctica goes to Borchgrevink who found quartz reefs near Duke of York Island justifying the belief that in time to come exploration will receive much support from commerce (Borchgrevink, 1900). Shackleton attempted to finance his expedition in part by floating mining shares. In 1908 at the top of the Beardmore Glacier on their march south, Wild discovered seams of coal between 4 ins and 7-8 ft thick (Shackleton,...

Krill Stocks

Many computations have been made of production and standing stock of krill, and most estimates of annual harvestable yield range from 100 to 150 million tonnes. These figures have been derived using a variety of approaches including the consumption of past and present stocks of whales (based on their length of residence in Antarctic waters, volume of stomach contents, and energy requirements) the consumption by other vertebrate predators the catch rates of krill in plankton nets and the...

Basins Of The Campbell Plateau

Campbell Plateau

The Campbell Plateau is a large submerged block of continental crust lying to the east and southeast of the South Island of New Zealand. This block was originally part of Gondwanaland and several tensional basins formed within it during its separation from Antarctica (Davey, this volume). Four of these basins have commercial potential for hydrocarbons. They are the Canterbury, Great South, Pukaki and Campbell Basins (Fig. 6.5) The Canterbury Basin lies to the east of the alpine area of the...

History Of Exploitation

Sealers from Britain and America were first on the scene, being attracted to the islands of the Scotia Sea, South Georgia and South Shetlands in particular. The elephant seal and Antarctic fur seal were the prime targets from about 1778 onwards, because of their valuable oil and fur respectively. Fig. 9.2. Relative abundance of krill and plankton (A), and relative feeding activity of the main Antarctic consumers (B), on a seasonal basis (after Laws, 1977). Fig. 9.2. Relative abundance of krill...

Ice Shelves And Other Marine Glaciers

Glaciers in contact with the sea can be given a general name of marine glaciers. Such glaciers are significant because their ice discharge is sufficient to bring them into contact with the sea and its powerful eroding forces. Most Antarctic glaciers reach the sea and some extend many hundreds of kilometres offshore. The Pacific Sector of the Antarctic contains a representative selection of different types of marine glaciers, from ice shelves to fjord glaciers to those that terminate on beaches...

Bellingshausen Sea To Ross

Ice Shwwt Antarctica Cross Section

Antarctica showing the extent of glacial ice in West and East Antarctica and ice shelves (shaded). The inset is a cross-section through the West Antarctic Ice Sheet which is grounded well below sea level in most places. Fig. 4.1. Antarctica showing the extent of glacial ice in West and East Antarctica and ice shelves (shaded). The inset is a cross-section through the West Antarctic Ice Sheet which is grounded well below sea level in most places. metres above sea level near the centre...

Effect Of The Antarctic Continent On Atmospheric Circulation In The Southern Ocean

The term katabatic (after Greek for go down) refers to a wind caused by the local descent of cold air down a slope. In the Antarctic, katabatic winds are a large-scale phenomenon, similar to trade winds in the magnitude of energy transfer (Weller, 1982). A high ice plateau, coupled with low cloud cover, permits intense radiational cooling near the ground, and this sets up strong surface inversions (i.e., air temperatures increase with height, which is the reverse of the normal situation in the...

Ross Ice Shelf

The Ross Ice Shelf is the largest ice shelf on earth having an area of 536,000 km2 (twice the area of New Zealand) and a volume of 23,000 km3 (Stuiver et al., 1981 Drewry, 1983). The ice shelf drains 2.86 million km2 (including the ice shelf itself) or 21 of Antarctica (Giovinetto and Bentley, 1985). Extensive field work in the 1970s, mainly under the Ross Ice Shelf Project (Thomas, 1979b), has made this the best known ice shelf. The thickness of Ross Ice Shelf is anything but regular (Bentley...

Tectonic History Of The Margins Of The Southern Pacific Ocean

Antarctica Climate During Cretatous

The Pacific Ocean margin of Gondwana (South America, Antarctica and Australasia), as noted earlier, had been an active orogenic zone from the Precambrian to the Late Cretaceous (Scotese, 1987). It formed the boundary zone between the Pacific Ocean and the stable shield area comprising the Precambrian meta-morphic rocks which occur in Brazil, Uruguay, northeastern Argentina, Falkland Islands, Falkland Plateau, East Antarctica and Australia. Knowledge of the area is highly variable reflecting the...

Mean Current Structure And Interaction With Bottom Topography

While the large-scale features of the mean surface circulation generally conform to the pattern imparted by wind forcing, this basic pattern is modified or perturbed by interaction of the flow with bottom topography. Sverdrup et al. (1942) pointed out that the configuration of the ACC is strongly influenced by major bathym trie features. With the exception of the large array of drifting buoys deployed during FGGE (Garrett, 1980), direct current observations in the Pacific Sector of the Southern...

Petroleum Products

It has been variously estimated that > 106 tonnes of petroleum hydrocarbons are yearly released into the marine milieu (NAS, 1975). Public sensitivity to the visual effects of oil slicks and tar balls (Butler, 1975a) ensures that this pollution problem attracts wide attention. The global distribution of pelagic oil and tar balls closely follows established tanker shipping routes (Levy et al., 1981). Anecdotal evidence, and what few data there are (e.g., Benzhitsky and Polikarpov, 1977...

Phytoplankton

Marine Phytoplankton Antarctica

The numerous phytoplankton investigations carried out in Antarctic waters during the past few decades have dealt primarily with the taxonomy and distribution of the organisms. The publications of Kozlova (1964) and Hasle (1969) dealing with the systematic composition and distribution of the phytoplankton (diatoms in particular) in the Pacific Sector of the Southern Ocean are of special interest. Very little attention has been given to the study of the life history, physiology, metabolism, and...

Physical And Chemical Characteristics

Convergence Front

The discussion of plankton in this chapter will be prefaced by a brief examination of the unique physical and chemical characteristics of the Antarctic seas, since these have a strong bearing on the biology, distribution, and abundance of the planktonic organisms. A more detailed account of the hydrology of the Pacific Sector of the Southern Ocean is given by Whitworth and Patterson (this volume). Unique features of the waters surrounding Antarctica include (a) the presence of pack-ice around...

Introduction Gp Glasby

For the English schoolboy brought up in the 1950s, Antarctica was synonymous with Scott's last expedition and Sir Clements Markham's (President of the Royal Geographical Society 1893-1905) romanticized version of the British bluejacket manhauling his sledge to the Pole. Yet the paradox of this view is readily apparent on re-reading the accounts of this expedition and observing that Scott's ship, Terra Nova, almost capsized in 1910 in a storm two days out from Port Chalmers, New Zealand. The sea...

Acknowled Gements

As editor, I would like to express my sincere thanks to all the contributors to this book for their tremendous effort in producing manuscripts, to Drs P.J. Barrett and T. Hatherton who kindly reviewed the entire book and D.G. Ainley, W.F. Budd, M.W. Cawthorn, A.E. Gilmour, C.H. Hay, J.R. Keys, K.B. Lewis, R.C. Murdoch, A.D. Pritchard, M.R. Sinclair and B.R. Stanton who reviewed individual chapters, to B. Grant for permission to reproduce the frontispiece, to Ms J.A. McDonald and Mr C.T. Pham...

Occurrence And Status Of Marine Mammals Whales

The Southern Hemisphere fossil record shows that whales have inhabited the region for over 40 million years from the Late Eocene to the present (Fordyce, 1985). The earliest cetaceans (archeocetes) were toothed whales, but opinions differ as to whether they gave rise to the modern toothed whales (odontocetes) and baleen whales (mysticetes) which appeared in the Oligocene (Barnes, 1984). Baleen whales are those that feed by straining krill or small fishes from the sea water through a filtering...

Seals

Fourteen species of seals are found in or adjacent to the Antarctic Sector of the Pacific. Breeding colonies occur on the coasts of southern New Zealand, southern Chile, the Subantartic islands, and on the ice itself. It was the Subantarctic and temperate seal colonies that attracted the 18th century sealers, and so started the massive depletion of marine mammal stocks in the Southern Ocean. Many Subantarctic islands were discovered by sealing expeditions. Between the late 1700s and 1830, many...

History Of Exploration

For any understanding of this region of the Southern Ocean, some historical perspective is necessary. Perhaps the most comprehensive summary of Antarctic exploration prior to the Heroic Age is that of Mill (1905). Other works consulted include Murray (1886,1894), Greely (1929), Fleming (1952), Priestley (1956), Kir-wan (1959), Brodie (1965), Quartermain (1967), M. Deacon (1971), G.E.R. Deacon (1975a, 1977a, 1984), Lovering and Prescott (1979), Shapley (1985), Walton and Bonner (1985), Hatherton...