Season :    2019

Voyage :     3

Cruise Name :     Southern Ocean Expedition-2009

Voyage Classification :      Ocean Science, Southern Ocean Studies

Ship Name :     R.V Akademik Boris Petrov

Name of Chief Scientist / Leader :     Dr. S.M. Pednekar, NCPOR, Goa.

Name of Deputy Chief Scientist / Leader :     Mr. Rohit Srivastsa PRL, Ahmeadabad.

The main objective of this cruise was to explore the Southern Ocean (SO) in its multi-disciplinary oceanographic, and atmospheric fields. A team of scientists from NCAOR, NIO, PRL, CMLRA, IMD, KBCAOS (Allahabad University), Goa University, Karnataka University, apart from the ship maintenance staff from NCAOR took part in the expedition. The data collection was so planned as to reoccupy some of the areas where earlier data were available and also to collect new data in some unexplored areas, whichwas not attempted earlier.

The Expedition was very successful and all the planned research activities were accomplished. For more details please refer Cruise report.

From	Depart	To	Arrive
Portluis, Mauritius	02/10/2009	Marmugao, Goa	04/14/2009

The vessel sailed off from Port Louis, Mauritius harbor on 12!" February 2009around 2100 hrs and after crossing Exclusive Economic Zone (EEZ) of Mauritius underway-geophysical data collection has been — started Immediately. From Mauritius, the vessel has sailed towards south and it has reached the starting location with coordinates 32°S and 57°30°E by 16"February 2009 at 1030 hrs. (Fig. 1) from which meridional section was sampled upto southernmost point 66°09.59’S. Southern Ocean (SO) is a region where Antarctic Circumpolar Current (ACC)encircles the Antarctic continent 360 days of the year. The SO plays a prominent role in controlling the global ocean—atmospheric Climate system and thereby having an impact on the climate of the earth. The various water masses of the world ocean Originate in this region. Under the changing atmospheric conditions, the vertical and horizontal structures of Antarctic Surface Water (AASW) of the Indian sector of the SO, as a whole, have not been studied to a greater extent, although some detailed studies exist for limited locations. These water masses play an important role in the global climate system as reservoirs of heat, freshwater and dissolved gases and act asa damping mechanism on variations in the global climate. Some studies have Shown that due to global warming, parts of Antarctic ice sheet are meltingand the SO is getting more and more melt water. The SO is also cha by high availability of macronutrients (phosphate, nitrate and silicate) which should sustain high primary productivity in that area. In spite of high macronutrient concentrations, chlorophyll and primary productivity are typical of oligotrophic to mesotrophic conditions in large areas of the SO.This region is very important reservoir which highly affects our monsoon system. SO is still not very much explored therefore various aspects has been taken up to explore the SO. It is in this context that the National Centre for Antarctic and Ocean Research (NCAOR), Goa initiated a multi-parameteroceanographic study in the SO sector of the India Ocean. Multiple Plankton Net (MPN) of mesh size 10 um and 100 um was operated(6 stations) to collect phytoplankton samples in the upper 200 m_ water column. Bongo net of mesh size 200 pm was dragged tor 10 minutes with 2knot ship speed at two degree interval to collect zooplankton samples in the surface water at 39 stations. Gravity corer was operated in the SO region however no sediment was collected could be due to bottom topography.Coastal sediment samples were collected in the Antarctic continental shelf in the zonal track using a Van veen grab. Benthic samples were collected at 3stations to study the benthic biology. Total 5 numbers of sediment (Grab)samples were collected. Hydrosweep swath underway bathymetry data and Parasound sub bottom profiler data were collected along ship track. Due to technical problems in Atlas Hydrosweep system, swath bathymetric data could not be collected in the return. Scientific observations and under way data acquisition stopped before entering EEZ of India. It is expected that this multi-disciplinary oceanographic data collected in the SO sector as well as in tropics will help to bring out new insights in our scientific understanding. Considering the requirement of the expedition member’s data collection during SO Expedition - 2009 is satisfactory although there were some instrumental errors occurred due to rough weather conditions at high seas. Even in the bed weather/rough sea conditions tremendous efforts were made by the expedition members for data collection which will help us for more scientific understanding of the unknown areas of Southern Ocean. Temperature - Salinity using CTD etc): Chemical parameters (Dissolved OXygen, pH. Nutrients, etc): Biological parameters (Phytoplankton. Chlorophyll, Zooplanktons & Benthos, Biochemical parameters, Biological species etc): Geological parameter (Gravity cores and Grab samples) and Geophysical parameters (Bathymetry, survey by Multi-beam sonar. And Parasound sub bottom profiling) were collected along meridional sections57°30°E and 48°E: along zonal section 65°30°S: and along the return track from Mauritius to India (Goa). Astronomical visual moving objects were identified in clear Sky with naked eyes. Aerosol Optical Depth (AOD) was measured at half hourly interval using Microtop I] sun-photometer during clear cloud free days throughout the cruise track. Meteorological parameters were measured using handheld equipments at 3 hourly intervals in conjunction with continuous AWS measurement (at one minute interval). CO, samples were collected from 17stations along 57°30’E. Air samples were collected from 97 stations. Surface sea water samples were collected from 107 stations at one degree interval after crossing EEZ of Mauritius i.e. southward from 25°S to study biogeochemical parameters. XBTs were launched at one-degree interval from28°S to 35°S (10 numbers). XCTDs were launched at 20 nautical mile interval from 35°30’S in the frontal region (45 numbers). Temperature salinity (CTD) data was collected using Mark IIIB CTD, 29 stations along57°30’E meridional section; 8 stations along 65°30’S zonal sections; 24Stations along 48°F meridional section; and 22 stations along Mauritius toI ndia (Goa) cruise track. At two degree interval rosette sampler was operated from 32°S onwards, however it was operated at one degree interval in tropics from Mauritius to India (Goa). Sea water samples were collected at different depths from ~56 stations along meridional sections 57°30°E and 48°E and in the return track from Mauritius to India (Goa) for analyzing various parameters such as dissolved Oxygen, pH, and nutrients (Nitrate, Nitrite. Phosphate and Silicate) etc. Further, sea water samples were collected for analyzing phytoplankton, chlorophyll and biogeochemical parameters.

a. Atmospheric Sciences Atmospheric data js Important as it plays major role in ocean dynamic processes. Participants from NCAOR (objectives 1-3), IMD & KBCAOS(objective 4), PRL (objectives 5-12) are involved in the atmospheric objectives. Aerosol particles data collection using Microtop II sun-photometry had been carried out by NCAOR. Meteorological data was collected at 1 minute interval using AWS (Automatic Weather Station) in the entire cruise track. Synoptic meteorological observations in 3 hourly intervals was carried out by IMD and KBCAQS. Study on stable isotopes of oxygen and hydrogen was done by PRL group.

Please refer Voyage Report

Please refer Voyage Report