5 - VOYAGE / SOUTHERN OCEAN EXPEDITION DETAILS
Season :    2011
Voyage :     5
Cruise Name :     Southern Ocean Expedition 2011
Voyage Classification :     Ocean Science, Southern Ocean Studies
Ship Name :     ORV Sagar Nidhi
Name of Chief Scientist / Leader :     Dr. N. Anilkumar, NCPOR, Goa.
Name of Deputy Chief Scientist / Leader :     Dr. R. Jeyabaskaran, CMFRI, Kochi.
The agenda for research in the Southern Ocean realm underlines the sensitivity of the Southern Ocean region to climatic variability and its importance in understanding the climate at large. The Southern Ocean research plan mainly focuses on:
“Role and response of Southern Ocean to the regional and global climate
Towards achieving this the following objectives have been identified:-
To study the inter relationship between physical, chemical and biological
elements occurring across the Antarctic Circumpolar Current (ACC) and
their role in carbon sequestration, biogeochemistry and climate change.
To investigate the air-sea-ice interaction and to understand the role of
anthropogenic aerosols over southern ocean and its effect on climate
To understand the implication of thermohaline variations in the Southern
Ocean and the repercussion of heat and mass exchange between tropics and
Polar Regions on Indian monsoon, biogeochemistry and climate.
Reconstruction of the paleo-environmental conditions for selected time slices
during the last glacial-interglacial cycles to provide perspectives on future
To generate relevant/critical sea truth and atmospheric data for contributing to global
climate data sets for prediction of climate models to mitigate/regulate climate change.
Within the frame work of the above mentioned major focal themes, studies were
conducted to investigate the following objectives:
1. Investigation of marine atmospheric surface layer and its dynamics.
2. Understanding the diurnal variations of physical properties and their impact
on chlorophyll concentrations in the major frontal regions.
3.Study the mechanism of maintenance of deep chlorophyll maximum in the frontal
4.Influence of mixed layer dynamics, Ekman dynamics, euphotic zone variations and
eddies on the chlorophyll distribution.
5.Monitoring the changes in the oceanic thermohaline structure along two meridional
repeat hydrographic sections.
6. Understanding the heat content and heat and mass transport in the study region.
7. Identifying water masses using stable isotopes ( 18 O).
8. Identify the relationship between oceanographic parameters and deep sea mega
fauna and marine mammals.
9.Investigation of the source, distribution, components and chemistry of suspended
10. Measuring the inherent bio-optical properties of SO waters.
11. Deriving quantitative information on the types of substances (e.g. chlorophyll
concentration, suspended matter, yellow substances, and attenuation coefficient )
present in the water and their concentrations, based on spectral variations.
12. Isolation and molecular characterization of novel microalgal species from SO
towards exploring their metabolic potential and biological variability.
13. Study the composition of phytoplankton communities in the region, using the
photosynthetic pigments as taxonomical biomarkers.
14. To determine possible relationship between phytoplankton communities (through
pigment composition) and the ACC fronts zones.
15. Diurnal variability in planktonic standing stock and diversity in the two major
fronts (Polar front and subtropical front)
The Expedition was very successful and all the planned research activities were accomplished. For more details please refer Cruise report.
Southern Ocean (SO), encircling the Antarctica starts from subtropical frontal region
around 35°S. SO plays a crucial role in regulating the global ocean atmospheric climate
system. The Antarctic land mass covered by glaciers is the source of fresh water to the SO.
Surface winds have a significant role in the mixing and dynamics of the SO. Wind driven
currents and fronts in SO aids in the formation of latitudinaly separated zones with distinct
physical and biological features. As compared to other oceanic regions SO is the least
investigated region. Presence of ice and challenging climatic conditions make scientific
measurements difficult here. Moreover, Indian Ocean sector of SO is a data sparse region.
As part of the ongoing efforts to broaden our understanding of Indian Ocean sector of
SO, the fifth Indian Scientific Expedition to SO was launched in January, 2011. The scientific
team set sail from Port Luis, Mauritius onboard ORV Sagar Nidhi on 24 th January, 2011. The
team comprised of 15 scientists from various national institutes and universities. Two
scientists from Federal University of Rio Grande (FURG, Brazil) also participated in the
Major operations carried out during the expedition were (i) Profiling of water column
using CTD and collection of water samples with attached rosette system up to 5300 m depth
(ii) Multiple plankton net sampling of zooplankton (iii) Bongo net deployment for collecting
surface zooplankton (iv) Firing of XCTDs to delineate the vertical structure of water column
in high resolution (v) Grab corer for sea bottom surface sampling (vi) Continuous
observations of atmospheric surface layer parameters using automatic weather station
(AWS). Time series observation of physical, chemical and biological parameters from two
different frontal regions was a major accomplishment of this year’s expedition. The data
generated during this expedition may throw more light into several intriguing aspects of the
a.Atmospheric Sciences (i) Atmospheric and Oceanic CO2 Budget (ii)Air Sea Interaction fluxes b.Physical oceanography c.Chemistry (i)Southern Ocean biogeochemical cycling ii)Bio optical properties of Southern Ocean iii)Investigation of mass concentration of suspended particulate matter iv) 6.3.4 Southern Ocean particle chemistry of the suspended matter and the seawater d.Biology i)Primary production and associated biologicalprocess and the variation of biological and physicochemical components with time ii) ACC fronts Interactions around Crozet Plateauregulation phytotoplankton Assemblage iii)Microalgal diversity in Southern Ocean iv) Surveys for marine mammals
Please refer Voyage Report
Please refer Voyage Report