Latitudinal metazoan plankton zones in the antarctic circumpolar current along 6°W during austral spring 1992

Fransz, H.G.; Gonzalez, Santiago R.

doi:10.1016/s0967-0645(96)00065-3

Cited by 70 publications

(34 citation statements)

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“…The sharp decrease in the microzooplankton abundance in this zone may also be the result of strong grazing pressure by large copepods and carnivorous zooplankton. Copepods were the dominant metazooplankton in the PFZ (Fransz & Gonzalez 1997). The mesozooplankton community was dominated almost entirely by copepods, which agrees with a number of previous studies (Pakhomov & Froneman 1999, Bernard & Froneman 2003, 2005.…”

Section: Discussionsupporting

confidence: 91%

Hydrographic and productivity characteristics along 45°E longitude in the southwestern Indian Ocean and Southern Ocean during austral summer 2004

Jasmine¹,

Muraleedharan

Madhu³

et al. 2009

Mar. Ecol. Prog. Ser.

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During the austral summer 2004, an intensive multidisciplinary survey was carried out in the Indian Ocean sector of the Southern Ocean to study the main hydrographic features and the associated productivity processes. This sector includes circumpolar zones and fronts with distinct hydrographic and trophic regimes, such as the Subtropical Zone (STZ), Subtropical Frontal Zone (STFZ), Subantarctic Zone (SAZ), Polar Frontal Zone (PFZ), North Subtropical Front (NSTF), Agulhas Retroflection Front (ARF), South Subtropical Front (SSTF), Subantarctic Front, Surface Polar Front (SPF), and Subsurface Polar Front. Seasonal variations in the solar irradiance and day length, stratification, lack of micronutrients like iron and increased grazing pressure are the major factors that influenced or constrained biological production in this region. Even though broad differences in these controlling factors exist in time and space between the zonal regions, the upper 1000 m of the water column of the main zones, STZ, STFZ, SAZ, PFZ, supported almost identical standing stocks of mesozooplankton, 0.43, 0.47, 0.45 and 0.49 ml m -3 , respectively, during the austral summer. This unexpected similarity can be explained either through the functioning of the microbial loop within STZ, STFZ and SAZ and the multivorous food web ecology within the PFZ. Dominance of ciliates in the microzooplankton community may be one factor resulting in the maintenance of a high mesozooplankton standing stock in SAZ. In contrast to the zones, frontal regions showed wide differences in hydrography and biological characteristics. The SSTF and SPF were far more biologically productive than that of NSTF and ARF. KEY WORDS: Fronts · Zones · Microzooplankton · Mesozooplankton · Microbial loop · Southern OceanResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 389: 97-116, 2009 et al. (1991) reported that seabirds and mammals may transfer 20 to 25% of photosynthetically fixed carbon into the atmosphere via respiration after consuming macrozooplankton and micronekton. Therefore, zooplankton occupies an important position in the Southern Ocean carbon cycle.The major current system in the Indian Ocean sector of the Southern Ocean is the Antarctic Circumpolar Current (ACC). The principal mechanism determining the different properties within the zones and along the frontal systems is the wind-induced transport (from the westerlies) that drives the uninterrupted eastward flowing ACC. Deacon (1933Deacon ( , 1937 was the first to outline the frontal systems in the Southern Ocean and suggested that they are circumpolar and other studies followed (Lutjeharms 1981, Deacon 1982, Belkin & Gordon 1996, Holliday & Read 1998, Froneman et al. 2000, Pollard & Read 2001. Along the 45°E longitude the main features are (from north to south), the existence of the North Subtropical Front (NSTF), Agulhas Retroflection Front (ARF), South Subtropical Front (SSTF), Subantarctic Front (SAF) and Polar Front (PF); the PF has both Su...

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Section: Discussionsupporting

confidence: 91%

Hydrographic and productivity characteristics along 45°E longitude in the southwestern Indian Ocean and Southern Ocean during austral summer 2004

Jasmine¹,

Muraleedharan

Madhu³

et al. 2009

Mar. Ecol. Prog. Ser.

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“…Research has been focused mainly on euphausiids (particularly Euphausia superba) and copepods, (e.g. ATKINSON, 1998;VORONINA, 1998;FRANSZ;GONZALEZ, 1997), while other components of the mesozooplankton have scarcely been investigated. However, they may play a major role in our understanding of the productivity of the Southern Ocean.…”

Section: Introductionmentioning

confidence: 99%

Distribution patterns of chaetognata, polychaeta, pteropoda and salpidae off south georgia and south orkney islands

et al. 2010

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The distribution pattern, frequency and density (ind./1000 m) of different mesozooplankton species from the South Georgia Islands, South Orkney Islands and the Weddell-Scotia Confluence were analyzed using data obtained in 1994. The maximum densities of the species found were: Eukrohnia hamata (5330), Sagitta gazellae (1052), Clione limacina antarctica (450), Spongiobranchaea australis (375), Clio sulcata (100), Limacina helicina (4076 x 10³), Limacina retroversa (71 x 10(4)), Pelagobia longicirrata (29170), Rhynchonereella bongraini (117), Tomopteris carpenterii (26), Tomopteris planktonis (498), Tomopteris septentrionales (498) and Salpa thompsoni (189). Species density and frequency decreased from South Georgia to the South Orkney Islands, recording intermediate values at the Weddell-Scotia Confluence. Species density in the South Orkney area seemed to be limited by variations in temperature and salinity. The southern area around South Georgia showed the highest density of species, probably due to the influence of the Southern Front of the Antarctic Circumpolar Current. The presence of species characteristic of sub-Antarctic waters such as L. retroversa in the Confluence area could be related to the southward movements of eddies that originate in the Polar Front.
Foram analisados os padrões de distribuição, freqüência e densidade (ind. 1000 m) de diferentes espécies de mesozooplâncton encontradas em torno das ilhas Georgias e Orcadas del Sur no verão de 1994. As densidades máximas apresentadas pelas espécies principais foram: Eukrohnia hamata (5330), Sagitta gazellae (1052), Clione limacina antarctica (450), Spongiobranchaea australis (375), Clio sulcata (100), Limacina helicina (4076 x 10³), Limacina retroversa (71 x 10(4)); Pelagobia longicirrata (29170), Rhynchonereella bongraini (117), Tomopteris carpenterii (26), Tomopteris planktonis (498), Tomopteris septentrionales (498) y Salpa thompsoni (189). A densidade e freqüência das espécies diminuíram das ilhas Georgias em direção às Orcadas, registrando-se valores médios na confluência Weddell-Scotia. A densidade de espécies nas Orcadas parece estar limitada pelas variações na temperatura e salinidade. Nas Georgias, a área sul mostrou a maior densidade de espécies, e isto poderia ser devido a influência da Frente sul da Corrente Circumpolar Antártica. A presença de espécies características de águas sub-antárticas (Ex. L. helicina) na confluência Weddel-Scotia poderia estar relacionada com o movimento dos vórtices da Frente Polar em direção Sul

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“…Small copepods in the size range of 100-2000 mm were extremely abundant in the upper mixed layer of most of the transect stations, reaching up to 49; 000 ind: m À3 : These concentrations were much higher than values obtained by Fransz and Gonzalez (1997), Errhif et al (1997) and Atkinson and Sinclair (2000) in the APF and nearby systems. Investigations in more southern regions of the Antarctic Ocean, such as coastal regions near the South Shetland Islands (Chojnacki and Weglenska, 1984;Park and Wormuth, 1993;Ward et al, 1995), the Scotia Sea (Marin, 1987), the Weddell Sea (Hopkins and Torres, 1988;, the Bellingshausen Sea (Metz, 1996), and an coastal area of Eastern Antarctica (Tucker and Burton, 1990), also revealed much lower numbers.…”

Section: High Abundances Of Zooplankton (Size Range 100-2000 Mm)mentioning

confidence: 68%

“…Copepod abundances of up to 8000 ind: m À3 and average zooplankton biomass of 1-2 g C m À2 have been recorded since then for the upper mixed layer of Antarctic and Subantarctic waters (Atkinson, 1996;Fransz and Gonzalez, 1997;Metz, 1995Metz, , 1996. Therefore, small copepods are undoubtedly more abundant than their larger counterparts, and their population biomass has been proposed to equal that of large calanoids (Metz, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…Such meanders and eddies may segregate different phytoplankton blooms within a few kilometers . Although evidence exists that frontal systems play a major role in macrozooplankton dynamics in the Southern Ocean (Huntley and Niller, 1995;Smith and Schnack-Schiel, 1990), the spatial distribution of small ðo2:0 mmÞ Antarctic and Subantarctic copepods has seldom been investigated in relation to hydrographical features (Errhif et al, 1997;Fransz and Gonzalez, 1997;Metz, 1995Metz, , 1996.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High summer abundances of small pelagic copepods at the Antarctic Polar Front—implications for ecosystem dynamics

Dubischar

Lopes

Bathmann

2002

Deep Sea Research Part II: Topical Studies in Oceanography

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Within the framework of the SO-JGOFS, we investigated the distribution of small copepods ðo2:0 mmÞ in relation to the hydrography of the Antarctic Polar Front during summer 1995/96. The community of small copepods was dominated by Oithona similis, followed by Oithona frigida and Ctenocalanus citer. The total abundance of these copepods was extremely high throughout the study area, with peaks of up to 49; 000 ind: m À3 ; to which naupliar and early copepodid stages (CI-CIII) contributed a high percentage. The accumulation of such a high standing-stock of small copepods is probably related to retention mechanisms provided by the meandering structure of the frontal system and to the biology of the dominant species Oithona similis, Oithona frigida, and Ctenocalanus citer.Stage distribution and metabolic demand of the dominant species indicate a very active and productive zooplankton community, with high grazing pressure on smaller plankton particles and faecal material, leading to high recycling efficiencies and low export rates due to sinking material. This study gives further support to recent findings that small copepod species and early developmental stages of all species are key components of the plankton food web of the Southern Ocean. r

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Latitudinal metazoan plankton zones in the antarctic circumpolar current along 6°W during austral spring 1992

Cited by 70 publications

References 32 publications

Hydrographic and productivity characteristics along 45°E longitude in the southwestern Indian Ocean and Southern Ocean during austral summer 2004

Hydrographic and productivity characteristics along 45°E longitude in the southwestern Indian Ocean and Southern Ocean during austral summer 2004

Distribution patterns of chaetognata, polychaeta, pteropoda and salpidae off south georgia and south orkney islands

High summer abundances of small pelagic copepods at the Antarctic Polar Front—implications for ecosystem dynamics

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