Hostname: page-component-7479d7b7d-qlrfm Total loading time: 0 Render date: 2024-07-11T07:12:45.831Z Has data issue: false hasContentIssue false
  • English
  • Français

Major elements, nutrients, and plankton biomass in the ice edge and an offshore region of the Indian Ocean sector of the Southern Ocean

Published online by Cambridge University Press:  27 October 2009

P. V. Shirodkar ,
J. I. Goes ,
R. Alagarsamy  and
S. P. Fondekar
P. V. Shirodkar
Affiliation:
National Institute of Oceanography, Dona Paula, Goa 403 004, India.
J. I. Goes
Affiliation:
National Institute of Oceanography, Dona Paula, Goa 403 004, India.
R. Alagarsamy
Affiliation:
National Institute of Oceanography, Dona Paula, Goa 403 004, India.
S. P. Fondekar
Affiliation:
National Institute of Oceanography, Dona Paula, Goa 403 004, India.
Get access Rights & Permissions [Opens in a new window]

Abstract

Physico-chemical and biological studies during the austral summer of 1986–87 in the ice-edge and a region offshore of Antarctica indicated significant spatial differences in concentrations of nutrients, dissolved oxygen (DO), Ca, Mg, and chlorophyll a, and in the rates of primary production. The waters within the ice-edge region were richer in nutrients and DO and showed a four-fold increase in chlorophyll a(1.98 mg m-3) and a 10-fold increase in primary productivity (0.74 mg C m-3 h-1) as compared with offshore waters. In the ice-edge region, Mg was high (1319 mg kg-1), whereas values of Ca (421.7 mg kg-1) were within the normal range. Offshore Ca (423.8 mg kg-1) and Mg (1297 mg kg-1) were within the expected limits. In the ice-edge region, Ca/Cl varied from 0.0202 to 0.0229, with a mean of 0.0220, and Mg/Cl varied from 0.0637 to 0.0737, with a mean of 0.0687. These figures were slightly higher than those offshore (Ca/Cl: 0.0205 to 0.0224, mean 0.0214; Mg/Cl: 0.0630 to 0.0693, mean 0.0657), indicating the addition of Mg to the waters in the ice-edge region. Nutrients in the ice-edge region showed increasing concentrations at deeper levels irrespective of their relationship with DO, indicating large amounts of preformed nutrients, a characteristic of Antarctic waters attributable to intense upwelling. Chlorophyll a showed a direct relation with primary productivity and an inverse relation with Mg, suggesting the release of Mg from biogenic matter. Offshore, phosphate-phosphorus (PO4-P) was significantly correlated with nitrate-nitrogen (NO3-N) and inversely correlated with primary productivity and chlorophyll a, indicating the utilization of PO4-P during high production. Significantly elevated concentrations of chlorophyll a, primary productivity and Mg, marked by a considerable decrease in nutrients, were observed at a frontal zone between 64° and 62°S.

Type
Articles
Information
Polar Record , Volume 28 , Issue 165 , April 1992 , pp. 127 - 136
Copyright
Copyright © Cambridge University Press 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allanson, B. R., Boden, B., Parker, L., and Duncombe, R. 1985. A contribution to the oceanology of the Prince Edward Islands. In: Siegfried, W. R., Condy, P. R., and Laws, R. M. (editors). Antarctic nutrient cycles and food webs. Berlin, Springer-Verlag: 38–45.CrossRefGoogle Scholar
Carpenter, J. H. and Manella, M. E. 1973. Magnesium to chlorophyllorinity ratios in seawater. Journal of Geophysical Research 78: 3621–26.CrossRefGoogle Scholar
Clowes, A. J. 1940. Phosphate andsilicateofthe Southern Ocean. Discovery Reports 19: 1–20.Google Scholar
Culkin, F. and Cox, R. A. 1966. Sodium, potassium, magnesium, calcium and strontium in seawater. Deep Sea Research 13: 789–804.Google Scholar
De Souza, S. N., Sardessai, S., and Sen, Gupta R. In preparation. Calcium, magnesium, sulfate and fluoride in the south western Indian/Antarctic Ocean.Google Scholar
El-Sayed, S. Z. and Taguchi, S. 1978. Primary production and standing crop of phytoplankton along the ice edge in the Weddell Sea. Deep Sea Research 28: 1017–32.CrossRefGoogle Scholar
Eppley, R. W., Rogers, J. N., and McCarthy, J. J. 1969. Half saturation constants for uptake of nitrate and ammonia by marine phytoplankton. Limnology and Oceanography 14: 912–20.CrossRefGoogle Scholar
Goes, J. I., Fondekar, S. P., and Parulekar, A. H. 1990. Standing crop and growth rates of net phytoplankton and nanoplankton in Antarctic waters. In: Dwivedi, S. N., Mathur, B. S., and Hanjura, A. K. (editors). Proceedings of workshop on Antarctic studies. New Delhi, Department of Ocean Development: 419–34.Google Scholar
Gordon, A. L. 1981. Seasonally of Southern Ocean seaice. Journal of Geophysical Research 86: 4193–97.CrossRefGoogle Scholar
Grasshoff, K. 1976. Methods of seawater analyses. Weinheim, Verlag Chemie.Google Scholar
Hameedi, M. J. 1978. Aspects of water column primary productivity in the Chukchi Sea during summer. Marine Biology 48: 37–46.CrossRefGoogle Scholar
Holm-Hansen, O. 1985. Nutrient cycles in Antarctic marine ecosystems. In: Siegfried, W. R., Condy, P. R., and Laws, R. M. (editors). Antarctic nutrient cycles andfood webs. Berlin, Springer-Verlag: 61–70.Google Scholar
Ivanenkov, V. N. and Gubin, F. A. 1960. Watermasses and hydrochemislry of the western and southern parts of the Indian Ocean. Transactions of the Marine Hydrophysical Institute, Academy of Sciences 22: 27–99.Google Scholar
Jacob, S. S. and Georgi, D. T. 1977. Observations on the south western Indian/Antarctic Ocean. In: Angel, M. (editor). A voyage of discovery. London, Pergamon Press: 43–84.Google Scholar
Jones, E. P., Nelson, D. M., and Treguer, P. 1990. Chemical oceanography. In: Smith, W. O. Jr (editor). Polar oceanography—part B: chemistry, biology and geology. San Diego, Academic Press.Google Scholar
Lutjeharms, J. R. I., Walters, N. M., and Allanson, B. R. 1985. Oceanic frontal systems and biological enhancement. in: Siegfried, W. R., Condy, P. R., and Laws, R. M. (editors). Antarctic nutrient cycles and food webs. Berlin, Springer-Verlag: 11–20.CrossRefGoogle Scholar
Marra, J., Houghton, R. W., Boardman, D. C., and Neale, P. J. 1982. Variability in surface chlorophyll-a at a shelf break front. Journal of Marine Research: 40 (3): 575–91.Google Scholar
Naik, S., Noronha, R. J., Shirodkar, P. V., and Sen, Gupta R. 1983. On the distribution of calcium, magnesium, sulfate and boron in the south western Indian Ocean region of the Southern Ocean. Scientific report of the First Indian Expedition to Antarctica. New Delhi, Department of Ocean Development, Technical Publication 1: 87–94.Google Scholar
Naqvi, S. W. A. 1986. Some oceanographic observations in polynya and along a section in the south west Indian/Antarctic Ocean. Scientific report on the Third Indian Expedition to Antarctica. New Delhi, Department of Ocean Development, Technical Publication 3: 75–85.Google Scholar
Pant, A. 1986. Studies on Antarctic phytoplankton. Scientific report on the Third Indian Expedition to Antarctica. New Delhi, Department of Ocean Development, technical publication 3: 87–96.Google Scholar
Pant, A. 1987. Variability in phytoplankton and zooplankton in the Indian sector of the Southern Ocean: role of nanoplankton in Antarctic waters. Report of the BIOMASS data analyses workshop on Antarctic phytoplankton-zooplankton relationship (Indian Pacific sectors of the Southern Ocean). College Station, TX.Google Scholar
Pant, A. 1988. Primary and extracellularproductivity during austral summer at 70°S, 12°E Antarctica. Scientific report on the Fifth Indian Expedition to Antarctica. New Delhi, Department of Ocean Development, Technical Publication 5: 311–20.Google Scholar
Pingree, R. D., Mardell, G. T., Holligan, P. M., Griffiths, D. K., and Smithers, J. 1987. Celtic sea and Armorican current structure and the vertical distributions of temperature and chlorophyll. Continental Shelf Research 1 (1): 96–116.Google Scholar
Ramaraju, D. V. and Somayajulu, Y. K. 1983. Some physical characteristics of the Antarctic and western Indian Ocean. Scientific report of the First Indian Expedition to Antarctica. New Delhi, Department of Ocean Development, Technical Publication 1: 186–90.Google Scholar
Qasim, S. Z. 1977. Biological productivity of the Indian Ocean. Indian Journal of Marine Sciences 16: 184–91.Google Scholar
Smith, W. O. Jr, and Nelson, D. M. 1985. Phytoplankton biomass near a receding ice edge in the Ross Sea. In: Siegfried, W. R., Condy, P. R., and Laws, R. M. (editors). Antarctic nutrient cycles and food webs. Berlin, Springer-Verlag: 70–77.CrossRefGoogle Scholar
Smith, W. O. Jr, and Sakshaug, E. 1990. Polar hytoplankton. In: Smith, W. O. Jr, (editor). Polaroceanography—part B: chemistry, biology and geology. San Diego, Academic Press.Google Scholar
Strickland, S. C. and Parsons, T. R. 1976. A practical handbook of seawater analysis. Ottawa, Bulletin of the Fisheries Research Board of Canada.Google Scholar