1.1 The Biogeography of the Southern Ocean

Claude De Broyer1 & Philippe Koubbi2
1 Royal Belgian Institute of Natural Sciences, Brussels, Belgium
2 Sorbonne Universités, UMR BOREA 7208, Université Pierre et Marie Curie, Muséum national d’Histoire naturelle, Paris, France




Biogeographic information is of fundamental importance in providing the necessary geospatial framework to the marine biodiversity knowledge and understanding, and for assessing its gaps. It is for example essential for discovering biodiversity hotspots, detecting impacts of environmental changes, monitoring biodiversity, and modelling future distributions. In the context of increasing human pressure, it appears a key resource for supporting conservation and sustainable management strategies and designing marine protected areas.

The Southern Ocean (SO) (Map 1), was the last discovered on Earth and some of its parts, far from the scientific stations and their supply-ship routes, remain unexplored. Its depths have only been sampled by a few dedicated exploratory campaigns.

0101_Map01_SO placenames.png
"Introduction Map 1
General map of the Southern Ocean.

The place-names used in the Atlas are based on the following gazetteers: SCAR Composite Gazetteer: https://data.aad.gov.au/aadc/gaz/scar/ , GEBCO Gazetteer of undersea

feature names: http://www.ngdc.noaa.gov/gazetteer/ , and USGS: United States Board of Geographic Names: http://geonames.usgs.gov/antarctic/" licensed under CC BY 4.0.

Characteristic temperature range Characteristic   salinity range WATER MASS BIOGEOGRAPHIC PROVINCE
New Zealand sector South Australian sector South American sector South African sector
Winter: 3 to 11,5°C Summer: 5,5 to 14,5°C 34,0 to 34,5‰ Subantarctic cold temperate Antipodean Kerguelenian Magellanic Kerguelenian
Mean range: 1.3 to 3.7°C Transitional zone Georgian
Winter: -1,8 to 0,5°C Summer: -1,0 to 3,5°C 33,0 to 34,0‰ Antarctic Rossian sub-P. Antarctic Scotian sub-P. Antarctic

Table 1 Characteristics of the water masses of the southern temperate and Antarctic regions with the corresponding biogeographic provinces (from Knox 1960)

Its biodiversity - adapted to extreme conditions of life - appears unique and at the same time vulnerable to effects of global change such as climate warming, UV exposure and ocean acidification. In places, the region is warming more rapidly than the global ocean average and the Southern Ocean acts as a sentinel in detecting the impact of environmental changes upon marine ecosystems. It is also well recognized that it plays a critical role in the global ocean circulation, biogeochemical cycles and climate by connecting the ocean basins and the upper and lower limbs of the ocean overturning circulation (Rintoul et al. 2009).

The extensive exploration and assessment of the Southern Ocean biodiversity by the Census of Antarctic Marine Life programme (CAML 2005-2010; see Chapter 1.2) and the intense compilation and validation efforts of biogeographic data by the SCAR Marine Biodiversity Information Network (www.biodiversity.aq ; see Chapter 2.1) and other Antarctic data centres provided a unique opportunity, a strong collaborative framework and the appropriate momentum to attempt to synthesise the current biogeography knowledge of the Southern Ocean. This new synthesis was able to draw on vastly improved occurrence datasets from recent decades, as well as on new insights provided by molecular and phylogeographic approaches, and new methods of analysis, visualisation, modelling and prediction of biogeographic distributions.

2. Mapping the Southern Ocean biodiversity patterns

2.1. Historical background

Since James Cook’s second voyage in 1772-1775, which allowed the first descriptions of Antarctic animals (the birds of South Georgia by Forster, from 1777), the naturalists onboard a number of pioneer Antarctic exploratory expeditions progressively revealed the composition of the unique Southern Ocean biodiversity (see Fogg 1992). (Fig. 1)

"Figure 1 Rate of description of Southern Ocean species (from Griffiths 2010)" licensed under CC BY 4.0.

The very first attempt to characterise the Southern Ocean zoogeography may be that of Allen (1878), who, on the basis of mammal distribution, distinguished 8 main zoogeographical regions (“realms”) on Earth. He named the last one the “Antarctic or South Circumpolar Realm” that was described as follows: “The Antarctic Realm …embraces not only the Antarctic Zone, but a large part of the cold south-temperate… It will hence include not only the few small groups of Antarctic Islands, but also Tierra del Fuego and the Falkland Islands, …, while some of its characteristic forms also extend to New Zealand, and even Australia and the Cape of Good Hope. The only mammals that can be considered as strictly characteristic of this region are Pinnipeds and Cetaceans, of which several genera of each are almost wholly restricted to it.”

Few years later, in his “Principles of Zoogeography” (1884), Gill, relying mostly on fish data and records along the southern South American coasts, distinguished an “Antarctalian Realm” that “may cover the antipodal ocean up the isocryme of 44°F” [i.e. 6.7°C] and a “Notalian Realm”, the south temperate realm, that “may provisionally be said to extend from the southern isocryme of 68° to that of 44°” [i.e. 20°C to 6.7°C]. It seems that Gill was the first to introduce an obvious reference to sea surface temperatures.

At the end of the 19th century, the important results of the Challenger voyage in 1872-1876 were published, describing parts of the fauna of Kerguelen, Heard, Crozet and Prince Edward Islands. The results of the German Polar Expedition to South Georgia in 1882-83, in particular Pfeffer 1890, were also available. This allowed Ortmann (1896) in his influential “Grundzüge der Marinen Tiergeographie” to attempt a first generalisation of the SO fauna distribution patterns. For the benthos of the “littoral life zone” (which limit was set at the depth to which daylight is able to penetrate, which was “about 400 m”) he distinguished an “Antarctic Region” (without stipulating its precise northern limits) with “numerous local faunas”, which comprised: 1. A supposed coastal circumpolar fauna (fairly unknown); 2. A “Chilean-Patagonian” fauna, which may likely include South Georgia, South Orkney and South Shetland Islands; 3. A (South African) “Cape” fauna; 4. An “Australian-New Zealand” fauna. An Antarctic Region was also recognised for the “pelagic life zone”, which was divided in two sub-regions: the “Antarctic-circumpolar sub-region” under sea ice influence, and the “Notal-circumpolar subregion”. He did not define precisely “notal” (see Baur 1896), but in a footnote he referred to the (loose) concept originally introduced by Gill (1884). The term “notal” was subsequently used inconsistently by some Russian workers but was unambigously rejected by Hedgpeth (1970).

Taking advantage of a new wealth of faunistic data collected by the Antarctic “heroic age” expeditions at the turn of the century (Belgica, Valdivia, Southern Cross, Gauss, Antarctic, Discovery, Scotia, Français, Pourquoi Pas, Terra Nova,…), Ekman (1935, 1953), in his seminal “Zoogeography of the Sea”, was the first to summarise Southern Ocean distributions in a comprehensive biogeographic scheme. Relying on both the hydrographic framework (in particular the sea surface temperatures) and mostly echinoderm and fish records, he divided the Southern Ocean shelf and slope fauna (<1000 m) into two main regions: an Antarctic Region and an Antiboreal Region, the latter corresponding to the Sub-Antarctic Region of subsequent authors such as Hedgpeth (1969). The Antarctic Region, with a suggested northern limit at the Antarctic Convergence, was subdivided into two sub-regions (or provinces): the “Low Antarctic”, which includes South Georgia and the Shag Rocks Bank, and the “High Antarctic” which includes the rest of the region. The High Antarctic was in turn subdivided into a “West Antarctic” sub-region (Weddell Sea, Peninsula and Scotia Arc islands) and the “East Antarctic” including the Ross Sea and the regions lying south of Australia.

His Antiboreal Region comprised a South American well-defined sub-region, several isolated oceanic islands and a possible Kerguelen sub-region. The South American sub-region includes south Chile from about 40-42°S, Tierra del Fuego, and the Patagonian shelf, which northern limit “may possibly be put as far north as Rio de la Plata mouth” (36°S), although Norman (1937), relying on the fish fauna, placed the boundary of his “Patagonian Region” at 42°S. Ekman noted the great similarity of the Falkland fauna with the Patagonian fauna. He grouped among the Antiboreal oceanic islands: Gough Island, Prince Edward and Marion Islands, Crozet Islands, Auckland and Campbell Islands (noting nevertheless their close affinities with New Zealand) and Macquarie Island, recognizing, however, that their fauna was still poorly known and that they do not form a homogeneous faunal region. Kerguelen Islands (grouped with Heard and McDonald Islands) is considered a transitional, mixed region with strong endemism (about 50%) as well as strong affinities both with the Antarctic but even stronger with cold temperate regions.

A general scheme for the littoral regions of the southern cold temperate and Antarctic zones was proposed by Knox (1960), based on wide information about oceanographic conditions and distribution patterns of shallow-water organisms. His occurrence dataset of macroalgae and several animal groups was limited to distribution data obtained to the lower depth limit of algal growth, which may restrict the comparison with previous and following studies taking also into account the deeper shelf benthos. After characterising the littoral zonation patterns of an array of species typical of the various southern regions considered (Table 1), Knox (1960) distinguished an Antarctic Region with two provinces: the Antarctic Province, which includes Bouvet and Heard Islands as well as the South Sandwich Islands, and the South Georgia Province, considered a very distinctive biogeographic unit. Within the Antarctic Province, two sub-provinces are further recognized: the Scotian sub-province comprising Antarctic Peninsula and the Scotia Arc, while the Ross Sea and adjacent regions are considered to be a separate Rossian sub-province. In the sub-Antarctic or cold temperate regions, the Kerguelenian Province is formed by the scattered islands of Prince Edward and Marion, Crozet, Kerguelen and Macquarie, and the Subantarctic islands near New Zealand are considered the Antipodean Province. The southernmost part of South America and the Falkland Islands constitutes the Magellanic Province (Map 2).

"Introduction Map 2
Biogeographic division of the littoral zone of the southern cold temperate and Antarctic regions according to Knox (1960)." licensed under CC BY 4.0.

Summarising the early works on Antarctic zoogeography done by ichthyologists (in particular Regan 1914 and Nybelin 1947) and relying on his more recent findings, Andriashev (1965) proposed a scheme based on coastal fishes, comprising an Antarctic Region with a Glacial Sub-Region and a Kerguelen Sub-Region. The Glacial Sub-Region comprised a South Georgian Province (South Georgia, South Sandwich Islands and Bouvet Island) and a Continental Province, which was in turn subdivided into an East Antarctic District (including the coasts from the eastern Ross Sea to the western Weddell Sea) and a West Antarctic District (Antarctic Peninsula, South Shetland and South Orkney Islands). His Kerguelen Sub-Region included Marion Island, the Crozet Islands, Kerguelen and Heard Islands, and Macquarie Island. At the difference of previous biogeographic schemes, Andriashev did not retain the sub-Antarctic islands into a Sub-Antarctic Region but kept them in a large Antarctic Region. This view was subsequently supported by DeWitt (1971).\

Although recognising that biogeographical regionalisation should ideally be carried out on the basis of distribution patterns of whole communities of organisms and should not be based only on data from any one group, Kussakin (1967) proposed a biogeography of Antarctic and sub-Antarctic waters based on his extensive studies on isopods and tanaids. These brooding peracarid crustaceans have poor dispersal capabilities and thus can be useful biogeographical indicators. Relying on endemism data and records down to 2000 m depth, and using Preston’s index to calculate affinities between localities, his zonation scheme retained three main regions: the Antarctic, Kerguelen and Patagonian Regions. The Antarctic Region comprised an East Antarctic Province extending from the eastern Weddell Sea to Eights Coast (at about 100°W), a Graham or West Antarctic Province (Bellingshausen Sea, Antarctic Peninsula, South Shetland and South Orkney Islands), and a South Georgia Province (South Georgia, Shag Rocks, South Sandwich Islands, and possibly Bouvet Island). The Kerguelen Region included a Macquarie Province, a Kerguelen Province (with Kerguelen and Heard Islands) and a Marion Province (with Marion, Prince Edward and Crozet Islands). The Patagonian Region comprised a Magellan Province (south Chile from 40-42°S, south Argentina from 40°S, Tierra de Fuego and Falkland Islands), an Arauca Province (central Chile) and an Argentinian Province (from 40°S to north of Rio de la Plata).

2.2. The Antarctic Map Folio Series (1967-1978) and beyond

The first comprehensive effort to systematically map the distribution of the Southern Ocean biota is due to the “Antarctic Map Folio Series” published by the American Geographical Society (1967-1978). At the same period, the “Biology of the Antarctic Seas” monographs (1964-1995, in the Antarctic Research Series, published by the American Geophysical Society) substantially contributed to document the Antarctic and sub-Antarctic biodiversity and its distribution. Five Antarctic Map Folios were devoted to marine biodiversity: the biogeography of macroalgae was covered by Balech et al. (1968), the invertebrates by Bushnell & Hedgpeth (1969), the fish by DeWitt (1971), the birds by Watson et al. (1971), and the mammals by Brown et al. (1974).

Resulting from these efforts, Hedgpeth (1969, 1970) biogeographic synthesis was the first modern attempt to establish the SO biological regionalisation on the basis of a largely documented and diverse dataset – the occurrence records of 17 benthic and 4 pelagic invertebrate taxonomic groups. Hedgpeth recognised two main Antarctic and Sub-Antarctic Regions. The Antarctic Region extended south of the Antarctic Convergence (as suggested initially by Ekman and essentially valid for plankton) and divided into a Continental or High Antarctic Sub-Region (with an extension to Bouvet Island and a second one to Heard Island), and a Scotia Sub-Region (Peninsula and Scotia Arc Islands) with a separate district (or sub-province) for South Georgia. The Sub-Antarctic Region included a Magellanic sub-Region, a large Kerguelen Sub-Region and a separate district for Tristan da Cunha and Gough Islands (Map 3).

Map 3

Hedgpeth’s biogeographic scheme, which was very close to Knox (1960)’s proposal for littoral regions, was widely accepted by subsequent workers analysing patterns at the level of the whole benthic fauna (e.g., White 1984; Arntz et al. 1997; Clarke & Johnston 2003) or at the level of particular taxa.

Soon after Hedgpeth’s contributions (1969, 1970, 1971), Dell (1972) published a comprehensive analysis of the Antarctic benthos, and critically reviewed the previous biogeographic schemes. He supported in general Hedgpeth’s scheme, but at the same time drew attention to the difficulties to properly define and delineate biogeographic provinces valid for many different organisms, bathymetric regions, or isolated islands. His view of the East Antarctic sub-region, including part of the Weddell and Bellingshausen Seas, is similar to Kussakin’s view. In contrast to the findings of Hedgpeth and Knox, he considered Heard Island – located south of the Antarctic Convergence - as essentially sub-Antarctic, like Kerguelen and Macquarie Islands.

From a detailed analysis of the benthic Amphipoda (450 spp., 2151 records) and the Polychaeta (558 spp., 4476 records), Knox & Lowry (1977) attempted a biogeographic synthesis of the Antarctic shelf benthos (<500 m). Their affinity matrix differentiated 4 distinct areas in the Southern Ocean: 1. The Sub-Antarctic area, which includes the Auckland and Campbell Islands, Macquarie Island, Kerguelen and Heard Islands, and the Prince Edward Islands; 2. The East Antarctic area, which includes the Ross Sea, the Adélie Coast and the Davis Sea; 3. The Scotia area, which includes South Georgia and the islands of the Scotia Arc, plus the South Shetland Islands and the islands along the western coast of the Antarctic Peninsula; 4: The Magellanic area, composed of the southern tip of South America, the Falkland Islands and the Burdwood Bank.

Briggs (1974, 1995) established a system of coastal and shelf provinces for the world ocean, which was largely based on fish distributions and defined by their degree of endemism (of >10%). For the Southern Ocean the system was recently reviewed by Briggs & Bowen (2012) relying in particular on the new inputs provided by Linse et al. (2006), Clarke et al. (2007) and Griffiths et al. (2009). They distinguished in their “Cold-Temperate and Polar Southern Hemisphere” zone, 4 regions and 13 provinces as follows: 1. South American Region, with 4 provinces: Southern Chile, Tierra del Fuego, Southern Argentina, Falkland Islands; 2. New Zealand–Australian Region, with 3 provinces: Tasmania, New Zealand, Antipodes; 3. Sub-Antarctic Region, with 6 provinces: South Georgia, Bouvet, Crozet, Prince Edward, Kerguelen, Macquarie; 4. Antarctic Region considered a single entity, without provincial subdivision, following the suggestion by Griffiths et al. (2009) (Map 4).

Map 4

This selective “historical” review, focusing mostly on benthos, showed the difficulties in adopting consistent concepts, methodology and terminology for establishing biogeographical subdivisions, but this has been a recurrent topic in biogeography (see the review of the biogeographic province concept by Lomolino et al. 2010).

Since Ekman (1953), all workers agreed on a latitudinal division between the southern part of the SO, the Antarctic zone located south of the Polar Front (or Antarctic Convergence), and a sub-Antarctic zone located north of the Polar Front, but with different northern limits and components according to the data used. Within the Antarctic zone, most authors recognised for the benthos a continental (“high Antarctic”) biogeographic unit around the continent and a longitudinal division into a “West Antarctic” part, including the Peninsula and (some of) the Scotia Arc Islands, and an “East Antarctic” part, of various extent but always including the Ross Sea. South Georgia is generally considered a distinct biogeographic unit, within the Antarctic zone. Within the sub-Antarctic zone, the southernmost South American shelf is always clearly individualised (with however different northern limits), and the various oceanic islands were grouped in different ways according to the taxa investigated and the level of their knowledge. Several authors identified the West Wind Drift (now Antarctic Circumpolar Current) as the main potential dispersal factor for the sub-Antarctic fauna, which may explain the faunal links between South America and the eastward sub-Antarctic islands or between New Zealand and South America.

2.3. The last decades: time of biodiversity

Probably triggered by the application of the Rio Convention on Biological Diversity (1992) and the threats of environmental change impacts, the last two decades have seen a strong resurgence of interest for biodiversity issues and the development of macroecological approaches. An important number of biogeographic studies of Antarctic taxa were published, some quite recently in connection with the Atlas project and the development of online, open-access biodiversity databases, such as SCAR-MarBIN/ANTABIF and OBIS (www.iobis.org). We may cite the following examples, limited to contributions dealing with the whole SO benthic fauna of selected taxonomic groups: sponges : Downey et al. (2012); hydrozoans: Peña Cantero & Garcia Carroscosa (1999); sea-anemones: Rodriguez et al. (2007) ; cephalopods: Collins & Rodhouse (2006); gastropods and bivalves: Linse et al. (2006), Clarke et al. (2007); pycnogonids: Munilla & Soler Membrives (2009), Griffiths et al. (2011); crustaceans: De Broyer et al. (2003); mysids: Petryashov (2007); amphipods: De Broyer & Jazdzeswki (1996), De Broyer et al. (2007); isopods: Brandt (1992, 1999); decapods: Gorny (1999), Boschi & Lavio (2005); bryozoans: Barnes & Griffiths (2008), Hayward (1995); ophiuroids: Martín-Ledo & López-González (2014); echinoids: David et al. (2005); ascidians: Primo & Vasquez (2007). This renewed interest in biodiversity patterns was noticeable also in plankton, fish (e.g. Gon & Heemstra 1990) or top predators studies. For the zooplankton, the SCAR “Continuous Plankton Recorder (CPR) Survey” (see Chapter 10.3) recently published the “Zooplankton Atlas of the Southern Ocean” (Mc Leod et al. 2010).

We will not try to summarize here the various findings of these recent contributions as most of their authors were invited to write a synthesis chapter in this Atlas.

Other recent studies on spatial patterns were oriented toward particular ecosystems, or regions of the Southern Ocean, e.g., Brandt et al. (2009) and Kaiser et al. (2011) on bathymetric distribution of benthos, Barnes et al. (2006) and Hogg et al. (2011) on South Georgia biodiversity, Arntz et al. (2006) on Bouvet island, Barnes et al. (2008) on South Orkney archipelago biodiversity, or Koubbi et al. (2011) on the d’Urville Sea demersal and pelagic fish fauna, to cite just a few.

Some more general overviews of patterns and processes of the SO biodiversity distribution were provided by Clarke (2008); Griffiths (2010); Convey et al. (2012, 2014); and Kaiser et al. (2013). In addition, Griffiths et al. (2009) attempted to generalise the SO benthic biogeography.

The first insights to the Southern Ocean deep sea biogeography were given by Brandt et al. (2007a, b, 2012) reporting the significant results of the ANDEEP campaigns in the deep basins of the Weddell and Scotia Seas. These investigations revealed high level of unknown abyssal biodiversity and showed that bathymetric and biogeographic trends varied between taxa. They also indicated that the Antarctic abyssal fauna has stronger links with other oceanic abyssal basins (particularly in the Atlantic) than with the Antarctic shelf fauna, but this is mainly valid for taxa with good dispersal capabilities. On the contrary, the poor dispersers include many species with high apparent SO endemism.

2.4. Ecosystem biogeography or the macroecological approach

Departing from the classical faunistic and floristic approach of biogeography, i.e. the “compositionist” approach, there were recent attempts to establish biogeographic classifications by reference to the characteristics of regional marine ecosystems, shaped by hydrographic features, oceanographic and bio-geochemical processes (i.e. the “functionalistic” approach).

The “ecological geography of the sea”. Longhurst (2007) proposed a new “ecological geography of the sea” based on regional oceanographic characteristics and on pelagic bio-geochemical data obtained from satellite imagery and in situ data. This classification, mostly applicable to the pelagic realm, identified seven biogeochemical provinces south of the Sub-Tropical Front, among the 50 provinces in 4 major biomes (Polar, Westerlies, Trades and Coastal) detected in the global ocean.

Within the “Polar Biome”, two provinces have been defined south of the Polar Front. The “Austral Polar Province” comprises the seasonally ice-covered sea from the coasts of the continent to the level of the Antarctic Divergence at 60-65°S and includes the Antarctic Peninsula as well as the Scotia Arc islands of South Orkney, South Sandwich and South Georgia. The “Antarctic Province” is an annular province lying between the Antarctic Divergence and the Polar Front at about 55°S, which is synonymous with the southern branch of the Antarctic Circumpolar Current (ACC). The Bouvet, Kerguelen and Heard islands are attributed to this province.

North to the Polar Biome lies the “Antarctic Westerly Winds Biome”, which includes the “Sub-Antarctic Water Ring Province” that is formed by the northern flow of the circumpolar ACC lying between the Sub-Tropical Front and the Polar Front and covering the Sub-Antarctic Zone and the Polar Frontal Zone. It is circled to the north by the “South Sub-Tropical Convergence Province” that covers the entire Sub-Tropical Convergence Zone at about 35-45°S, marking the boundary between waters of sub-Tropical and sub-Antarctic origin. The Patagonian shelf and the Falkland plateau are parts of the “Southwest Atlantic Shelves Province” within the “Atlantic Coastal Biome”. This province extends from the latitude of Mar del Plata (38°S) to the tip of Tierra del Fuego at 55°S. On the Pacific side, the south Chilean waters are included in the “Humboldt Current Coastal Province” within the “Pacific Coastal Biome”. The sub-Antarctic islands of New Zealand on the Campbell and Bounty plateaus are part of the “New Zealand Coastal Province” within the same “Pacific Coastal Biome” (Map 5).

Map 5

The Large Marine Ecosystems of the World. With a perspective to support the application of practical management issues for the marine ecosystem goods and services, the system of “Large Marine Ecosystems” (LME) (http://www.lme.noaa.gov) was conceived by a number of regional experts to classify relatively large marine regions (on the order of 200,000 km2 or greater), characterized by distinct bathymetry, hydrography, productivity, and trophic relationships. Based on these four ecological criteria, 64 LME’s have been delineated around the ocean coastal margins. The Antarctic LME (# 61) includes the shelf around the continent (with the Peninsula) to a depth of 1000 m. The Patagonian Shelf (LME # 14) extends from the southernmost tip of South America to north of the mouth of Rio de la Plata and includes the Falkland Islands.

The “Marine Ecoregions of the World”. Aiming at supporting global and regional strategies for the conservation and sustainable use of marine resources, the “Marine Ecoregions of the World” (MEOW) system consists of a bioregionalisation of coastal and shelf areas (Spalding et al. 2007). MEOW is a nested system of 12 realms, 62 provinces and 232 ecoregions, based on “taxonomic configurations influenced by evolutionary history, patterns of dispersal, and isolation”. The Southern Ocean is classified as one realm comprising 4 provinces (Continental High Antarctic, Scotia Sea, Sub-Antarctic Islands, Sub-Antarctic New Zealand) sub-divided into 21 ecoregions, mostly based upon Linse et al. (2006) results (Map 6).

Map 6

The deep ocean floor. As largely confirmed by the ANDEEP results (see supra), the SO deep sea fauna clearly exhibits different composition and distribution patterns than the coastal and shelf faunas. Watling et al. (2013) proposed a deep-sea biogeographic classification for the lower bathyal and abyssal benthos of the global ocean. After reviewing existing classifications and data, they conducted a comprehensive analysis of high-resolution data of depths, water mass characteristics (temperature, salinity and dissolved oxygen) and particulate organic flux to the seafloor, encompassing two large bathymetric zones: the lower bathyal, set at 801–3500 m, and the abyssal, 3501–6500 m. Due to the limitation of available biotic data, these physical and chemical proxies were selected as potential good predictors of the distributions of deep-sea floor organisms. This process resulted in the delineation of 14 lower bathyal and 14 abyssal provinces, which are “to be considered as hypothetical”, and “need to be tested with species distribution data” (Maps 7, 8).

Map 7

Map 8

3. The Biogeographic Atlas project

Taking advantage of an unprecedented amount, availability, diversity, and quality of biogeographic data, and of new conceptual and methodological developments in biogeography, the Atlas contributors have attempted to establish a benchmark of the Antarctic and sub-Antarctic biogeography knowledge, covering a large number of species and assemblages from the phyto- and zooplankton, macroalgae and zoobenthos, nekton, and birds and mammals top predators. More than 140 contributors (biogeographers, taxonomists, ecologists, molecular biologists, IT experts, environmental dataset providers, modellers, and GIS experts) contributed to the Atlas, under the aegis of SCAR.

This Biogeographic Atlas is based on the analysis of more than 1.07 million occurrence records of 9064 validated species from ~434,000 distinct sampling stations. It presents a collection of 66 syntheses describing the distribution patterns and processes of a significative representation of Southern Ocean organisms, illustrated by more than 800 selected distribution maps. The Atlas covered the Southern Ocean at large, south of the Sub-Tropical Front, but focused in particular to the Southern Ocean s.s., the Antarctic region, south of the Antarctic Polar Front. Most analyses and syntheses relied on data south of 40°S; however, some few studies were limited to the Southern Ocean s.s..

Preceding the analysis and synthesis phases, the first and fundamental step of the Atlas project was to compile and database all occurrence records available from the literature (since the very beginning of Antarctic exploration), from museum collections, as well as from CAML and other recent Antarctic sampling campaigns. This required facing problems of data discovery, data quality assessment, correct interpretation and standardisation, and, vitally, required significant validation effort by numerous experts. It is important here to emphasize the key role of basic descriptive taxonomy in gaining these results. Despite being often disregarded by funding agencies, morphology-based taxonomical identification remains an essential step in biodiversity studies, and has to be supported in conjunction with molecular taxonomy in an integrative approach (see De Broyer & Danis 2011).

This wealth of expert-validated data has been made publicly available on the SCAR-MarBIN/ANTABIF portal (www.biodiversity.aq), allowing further improvements and additions, as well as multiple uses and applications, including in particular the predictive modelling of biogeographic distributions in face of the potential impacts of environmental changes.

This “Biogeographic Atlas of the Southern Ocean” is primarily intended to fulfil the needs of biogeographic information for science, conservation, monitoring and sustainable management of the Southern Ocean, in the context of environmental changes and increasing human pressure.

In addition to this printed version, a digital dynamic version of this Atlas with further functionalities is developed on the www.biodiversity.aq portal.


We are grateful to Huw Griffiths (BAS, Cambridge) and Ben Raymond (AAD, Hobart) for the preparation of the maps. This is CAML contribution # 88.


Allen, J.A., 1878. The geographical distribution of the Mammalia, considered in relation to the principal ontological regions of the earth, and the laws that govern the distribution of animal life. Bulletin of the US Geological Survey 4, 376 pp.

Andriashev, A.P., 1965. A general review of the Antarctic fish fauna. In: Van Mieghem, J., Van Oye, P., Schell, J., (eds.). Biogeography and Ecology in Antarctica. The Hague: Jung, pp. 491-550.

Arntz, W.E. (ed.), 2006. Macrobenthic studies at Bouvet Island. Results from the Expedition ANTARKTIS XXI/2 to Bouvet Island, carried out from on board RV Polarstern in 2003-2004. Polar Biology, 29(2), 81-151.

Barnes, D.K.A., Griffiths, H.J., 2008. Biodiversity and biogeography of southern temperate and polar bryozoans. Global Ecology and Biogeography, 17, 84-99.

Baur, G., 1896. Scientific literature. Grundzüge der Marinen Tiergeographie. Science 3, 359-367.

Balech, E., El-Sayed, S.Z., Hasle, G., Neushul, M., Zaneveld, J.S., 1968. Primary productivity and benthic marine algae of the Antarctic and Subantarctic. Antarctic Map Folio Series, Folio 10. New York: American Geographical Society.

Barnes, D.K.A., Griffiths, H.J., 2008. Biodiversity and biogeography of southern temperate and polar bryozoans. Global Ecology and Biogeography, 17, 84–99.

Boschi, E.E., Gavio, M.A., 2005. On the distribution of decapods crustaceans from the Magellan Biogeographic Province and the Antarctic region. Scientia Marina, 69, (Suppl. 2), 195-200.

Brandt, A., 1992. Origin of Antarctic Isopoda (Crustacea, Malacostraca). Marine Biology, 113, 415-423.

Brandt, A., 1999. On the origin and evolution of Antarctic Peracarida (Crustacea, Malacostraca). Scientia Marina, 63 (Supl. 1): 261-274.

Brandt, A., De Broyer, C., De Mesel, I., Ellingsen, K.E., Gooday, A.J., Hilbig, B., Linse, K., Thomson, M.R.A., Tyler, P. A. 2007a. The biodiversity of the deep Southern Ocean benthos. Philosophical Transactions of the Royal Society of London, Biological Sciences, 362, 39-66.

Brandt, A., Gooday, A.J., Brandao, S.N., Brix, S., Brokeland, W., Cedhagen, T., Choudhury, M., Cornelius, N., Danis, B., De Mesel, I., Diaz, R.J., Gillan, D.C., Ebbe, B., Howe, J.A., Janussen, D., Kaiser, S., Linse, K., Malyutina, M., Pawlowski, J., Raupach, M., Vanreusel, A., 2007. First insights into the biodiversity and biogeography of the Southern Ocean deep sea. Nature, 447, 307-311.

Brandt, A., De Broyer, C., Ebbe, B., Ellingsen, K.E., Gooday, A.J., Janussen, D., Kaiser, S., Linse, K., Schueller, M., Thomson, M.R.A., Tyler, P. A., Vanreusel, A., 2012. Southern Ocean deep benthic biodiversity. In: Rogers, A.D., Johnston, N.M., Murphy, E.J., Clarke, A. (eds.). Antarctic ecosystems: an extreme environment in a changing world. Wiley-Blackwell, pp. 291-334.

Brandt, A., Linse, K., Schüller, M., 2009. Bathymetric distribution patterns of Southern Ocean macrofaunal taxa: Bivalvia, Gastropoda, Isopoda and Polychaeta. Deep Sea Research Part I: Oceanographic Research Papers, 66 (11), 2013-2026.

Briggs, J.C., 1974. Marine biogeography. New York: McGraw-Hill Series in Population Biology. 475 pp.

Briggs, J.C., 1995. Global biogeography. New York: Elsevier. 452 pp.

Briggs, J.C., Bowen, B.W., 2012. A realignment of marine biogeographic provinces with particular reference to fish distributions. Journal of Biogeography, 39, 12–30.

Brown, S.G., Brownell, R.L. Jr., Erickson, A.W., Hofman, R.J., Llano, G.A., Mackintosh, N.A., 1974. Antarctic mammals. Antarctic Map Folio Series, Folio 18. New York: American Geographical Society.

Bushnell, V.C., Hedgpeth, J.W. (eds.), 1969. Distribution of selected groups of marine invertebrates in waters south of 35°S latitude. Antarctic Map Folio Series, Folio 11. New York: American Geographical Society.

Clarke, A., 2008. Antarctic marine benthic diversity: patterns and processes. Journal of Experimental Marine Biology and Ecology, 366, 48-55.

Clarke, A., Johnston, N.M., 2003. Antarctic marine benthic diversity. Oceanography and Marine Biology: an Annual Review, 41, 47-114.

Clarke, A., Griffiths, H.J., Linse, K., Barnes, D.K.A., Crame, J.A., 2007. How well do we know the Antarctic marine fauna? A preliminary study of macroecological and biogeographical patterns in Southern Ocean gastropod and bivalve molluscs. Diversity and Distributions, 13, 620-632.

Collins, M.A., Rodhouse, P.G., 2006. Southern Ocean cephalopods. Advances in Marine Biology, 50, 191-265.

Convey, P., Barnes, D.K.A., Griffiths, H.J., Grant, S.M., Linse, K., Thomas, D.N., 2012. Biogeography and regional classifications of Antarctica. In: Rogers, A.D., Johnston, N.M., Murphy, E.J., Clarke, A. (eds.). Antarctic Ecosystems: An extreme environment in a changing world, pp. 471-491.

Convey, P., Chown, S.L., Clarke, A., Barnes, D.K.A., Bokhorst, S., Cummings, V., Ducklow, H.W., Frati, F., Green, T.G.A., Gordon, S., Griffiths, H.J., Howard-Williams, C., Huiskes, A.H.L., Laybourn-Parry, J., Lyons, W.B., McMinn, A., Morley, S.A., Peck, L.S., Quesada, A., Robinson, S.A., Schiaparelli, S., Wall, D.H., 2014. The spatial structure of Antarctic biodiversity. Ecological Monographs, 84(2), 203-244.

David, B., Choné, T., Festeau, A., Mooi, R., De Ridder, C., 2005a. Biodiversity of Antarctic echinoids: A comprehensive and interactive database. Scientia Marina, 69, 201–203.

De Broyer C., Danis B., 2011. How many species in the Southern Ocean? Towards a dynamic inventory of the Antarctic marine species. Deep-Sea Research II, 58, 5-17.

De Broyer, C., Jazdzewski, K., 1996. Biodiversity of the Southern Ocean: towards a new synthesis for the Amphipoda (Crustacea). Bolletino del Museo Civico di Storia Naturale di Verona, 20(2): 547-568.

De Broyer, C., Jazdzewski, K., Dauby, P., 2003. Biodiversity patterns in the Southern Ocean: lessons from Crustacea. In: Huiskes, A.H.L., Gieskes, W., Rozema ,J., Schorno, R.M.L., Van der Vries, S.M., Wolf, F.W.J., (eds.). Antarctic biology in a global context. Leiden: Backhuys, pp 201-214.

De Broyer, C., Lowry, J.K., Jazdzewski, K., Robert, H., 2007. Catalogue of the Gammaridean and Corophiidean Amphipoda (Crustacea) of the Southern Ocean with distribution and ecological data. In: De Broyer C.,ed. Census of Antarctic Marine Life. Synopsis of the Amphipoda of the Southern Ocean. Vol. 1, Part 1. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, Biologie, 77(Suppl. 1), 1-324.

Dell, R.K., 1972. Antarctic benthos. Advances in Marine Biology, 10, 1-216.

DeWitt, H.H., 1971. Coastal and deep-water benthic fishes of the Antarctic. Antarctic Map Folio Series, Folio 15. New York: American Geographical Society.

Downey, R.V., Griffiths, H.J., Linse, K., Janussen, D., 2012. Diversity and distribution patterns in high southern latitude sponges. PLos One, 7(7), e41672. doi:10.1371/journal.pone.0041672.

Ekman, S., 1935. Tiergeographie des Meeres. Leipzig: Akademie Verlagsgesellschaft. 542 pp.

Ekman, S., 1953. Zoogeography of the sea. London: Sidgwick and Jackson Ltd. 417 pp.

Fogg, G.E., 1992. A history of Antarctic Science. Cambridge University Press. 483 pp.

Forster, G., 1777. A Voyage Round The World, In His Britannic Majesty’s Sloop, Resolution, commanded by Capt. James Cook, during the Years 1772, 3, 4, and 5. London.

Gill, T., 1884. The Principles of Zoogeography. Proceedings of the Biological Society of Washington 2, 1-39.

Gon, O., Heemstra, P.C., 1990. Fishes of the Southern Ocean. Grahamstown : J.L.B. Smith Institute of Ichthyology, 462 pp.\

Gorny, M., 1999. On the biogeography and ecology of the Southern Ocean decapods fauna. Scientia Marina, 63, (supl.1), 367-382.

Griffiths, H.J., Barnes, D.K.A., Linse, K., 2009. Towards a generalized biogeography of the Southern Ocean benthos. Journal of Biogeography, 36, 162-177.

Griffiths, H.J., 2010. Antarctic marine biodiversity – What do we know about the distribution of life in the Southern Ocean? Plos One, 5(8), e11683.

Griffiths, H.J., Aranga, C.P., Munilla, T., McInnes, S.J., 2011. Biodiversity and biogeography of Southern Ocean pycnogonids. Ecography, 34, 616-627.

Hayward, P.J., 1995. Antarctic cheilostomatous Bryozoa. Oxford: Oxford University Press. 355 pp.

Hedgpeth, J.W., 1969. Introduction to Antarctic zoogeography. In: Bushnell V.C., Hedgpeth J.W. (eds.), 1969.

Distribution of selected groups of marine invertebrates in waters south of 35°S latitude. Antarctic Map Folio Series, Folio 11, New York: American Geographical Society. pp. 1-9.

Hedgpeth, J.W., 1970. Marine biogeography of the Antarctic regions. In: Holdgate M.W. (ed.) Antarctic Ecology. Academic Press Inc., London. 1, pp. 97-104.

Hedgpeth, J.W., 1971. Perspective of benthic ecology in Antarctica. In: Quam L.O., Porter H.D., (eds.). Research in the Antarctic. A symposium presented at the Dallas meeting of the American Association for the Advancement of Science, December 1968, pp. 93-136.

Kaiser, S., Brandao, S.N., Brix, S., Barnes, D.K.A., Bowden, D.A., Ingels, J., Leese, F., Schiaparelli, S., et al. 2013. Patterns, processes and vulnerability of Southern Ocean benthos: a decadal leap in knowledge and understanding. Marine Biology, 160, 2295-2317. doi:10.1007/s00227-013-2232-6.

Knox, G.A., 1960. Littoral ecology and biogeography of the southern oceans. Proceedings of the Royal Society B 152 (949), 577-624.

Knox, G.A., Lowry, J.K., 1977. A comparison between the benthos of the Southern Ocean and the North Polar Ocean with special reference to the Amphipoda and the Polychaeta. In: Dunbar, M. (ed.). Polar Oceans. Proceedings of the Polar Oceans Conference, Montreal, May 1974. Arctic Institute of North America, Calgary, pp. 423-462.

Koubbi, P., Ozouf-Costaz, C., Goarant, A., Moteki, M., Hulley, P.-A., Causse, R., Dettai, A., Duhamel, G., Pruvost, P., Tavernier, E., Post, A.L., Beaman, R.J., Rintoul, S.R., Hirawake, T., Hirano, D., Ishimaru, T., Riddle, M., Hosie, G., 2010. Estimating the biodiversity of the East Antarctic shelf and oceanic zone for ecoregionalisation: Example of the ichthyofauna of the CEAMARC (Collaborative East Antarctic Marine Census) CAML surveys. Polar Science, 4, 115-133.

Kussakin, O.G., 1967. [Fauna of Isopoda and Tanaidacea from the coastal zones of the Antarctic and Subantarctic waters]. Issledovaniya Fauny Morei 4 (12). (In Russian). [English translation in: Biological Reports of the Soviet Antarctic Expedition (1955-1958), 3, 220-389. Jerusalem, 1968]

Linse, K., Griffiths, H.J., Barnes, D.K.A., Clarke, A., 2006. Biodiversity and biogeography of Antarctic and sub-Antarctic Mollusca. Deep-Sea Research II, 53 (8-10), 985-1008.

Lomolino, M.V., Riddle, B.R., Whittaker, R.J., Brown, J.H., 2010. Biogeography. Fourth Edition. Sunderland, MA: Sinauer Associates. 878 pp.

Longhurst, A.R., 2007. Ecological geography of the sea. Second edition. San Diego: Academic Press. 542 pp.

Martín-Ledo, R., López-González, P.J., 2014. Brittle stars from Southern Ocean (Echinodermata: Ophiuroidea). Polar Biology, 37, 73-88.

McLeod, D.J., Hosie, G.W., Kitchener, J.A., Takahashi, K.I., Hunt, B.P.V., 2010. Zooplankton Atlas of the Southern Ocean: The SCAR SO-CPR Survey (1991-2008). Polar Science, 4(2), 353-385.

Munilla, T., Soler Membrives, A., 2009. Check-list of the pycnogonids from Antarctic and sub-Antarctic waters: zoogeographic implications. Antarctic Science, 21(2), 99-111.

Norman, J.R., 1937. Coast fishes. 2. The Patagonian Region. Discovery Reports 16.

Nybelin, O., 1947. Antarctic fishes. Scientific Results of the Norwegian Antarctic Expeditions 1927-1928, 26, 1-76.

Ortmann, A.E., 1896. Grundzüge der Marinen Tiergeographie. Jena: Gustav Fischer. 96 pp.

Peña Cantero, A.L., Garcia Carrascosa, A.M., 1999. Biogeographical distribution of the benthic thecate hydroids collected during the Spanish “Antartida 8611” expedition and comparison between Antarctica and Magellan benthic hydroid faunas. Scientia Marina, 63 (Supl. 1), 209-218.

Petryashov, V.V., 2007. Biogeographical division of Antarctic and Subantarctic by Mysid (Crustacea: Mysidacea) fauna. Russian Journal of Marine Biology, 33(1), 1-16.

Pfeffer, G., 1890. Niedere Tierwelt des antarktischen Ufergebietes. Internat. Polarforsch. Deutsch. Exped. II.

Primo, C., Vazquez, E., 2007. Zoogeography of the Antarctic ascidian fauna in relation to the sub-Antarctic and South America. Antarctic Science, 19(3), 321-336.

Regan, C.T., 1914. Fishes. British Antarctic (“Terra Nova”) Expedition 1910, Natural History Report, Zoology, 1, 1-54.

Rintoul, S., Sparrow, M., Meredith, M., Wadley, V., Speer, K., Hofmann, E., Summerhayes, C., Urban, E., Bellerby, R., Ackley, S., Alverson, K., Ansorge, I., Aoki, S., Azzolini, R., Beal, L., Belbeoch, M., Bergamasco, A., Biuw, M., Boehme, L., Budillon, G., Campos, L., Carlson, D., Cavanagh, R., Charpentier, E., Chul Shin, H., Coffin, M., Constable, A., Costa, D., Cronin, M., De Baar, H., De Broyer, C., De Bruin, T., De Santis, L., Butler, E., Dexter, P., Drinkwater, M., England, M., Fahrbach, E., Fanta, E., Fedak, M., Finney, K., Fischer, A., Frew, R., Garzoli, S., Gernandt, H., Gladyshev, S., Gomis, D., Gordon, A., Gunn, J., Gutt, J., Haas, C., Hall, J., Heywood, K., Hill, K., Hindell, M., Hood, M., Hoppema, M., Hosie, G., Howard, W., Joiris, C., Kaleschke, L., Kang, S., Kennicutt, M., Klepikov, A., Lembke-Jene, L., Lovenduski, N., Lytle, V., Mathieu, P., Moltmann, T., Morrow, R., Muelbert, M., Murphy, E., Naganobu, M., Naveira Garabato, A., Nicol, S., O’Farrell, S., Ott, N., Piola, A., Piotrowicz, S., Proctor, R., Qiao, F., Rack, F., Ravindra, R., Ridgway, K., Rignot, E., Ryabinin, V., Sarukhanian, E., Sathyendranath, S., Schlosser, P., Schwarz, J., Smith, G., Smith, S., Southwell, C., Speich, S., Stambach, W., Stammer, D., Stansfield, K., Thiede, J., Thouvenot, E., Tilbrook, B., Wadhams, P., Wainer, I., Willmott Puig, V., Wijffels, S., Woodworth, P., Worby, T., Wright, S., 2012. The Southern Ocean observing system: Initial science and implementation strategy. SCAR & SCOR, 74 pp.

Rodriguez, E., Lopez-Gonzalez, P.J., Gili, J.M., 2007. Biogeography of Antarctic sea anemones (Anthozoa, Actiniaria): what do they tell us about the origin of the Antarctic benthic fauna? Deep Sea Research II, 54, 1876-1904.

Spalding, M.D., Fox, H.E., Allen, G.R., Davidson, N., Ferdana, Z.A., Finlayson, M., Halpern, B.S., Jorge, M.A., Lombana, A., Lourie, S.A., Martin, K.D., McManus, E., Molnar, J., Reccia, C.A., Robertson, J., 2007. Marine ecoregions of the world: a bioregionalization of coastal and shelf areas. Bioscience , 57(7), 573-583.

Watling, L., Guinotte, J., Clark, M.R., Smith, C.R., 2012 A proposed biogeography of the deep ocean floor. Progress in Oceanography, 111, 91-112.

Watson, G.E., Angle, J.P., Harper, P.C., Bridge, M.A., Schlatter, R.P., Tickell, W.L.N., Boyd, J.C., Boyd, M.M., 1971. Birds of the Antarctic and Subantarctic. Antarctic Map Folio Series, Folio 14. New York: American Geographical Society.

White, M.G., 1984. Marine Benthos. In: Laws, R.M. (ed.). Antarctic ecology. Vol. 2. London: Academic Press, pp. 421-461.

April 30, 2020