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Environment and Productivity patterns of Indian EEZ
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ENVIRONMENT AND PRODUCTIVITY PATTERNS IN THE
INDIAN
EXCLUSIVE ECONOMIC ZONE
AND
STUDIES ON MARINE MAMMALS OF THE INDIAN EEZ
AND THE CONTIGUOUS SEAS
Cruise Report 237 (I leg)
ARABIAN SEA
SUMMER MONSOON
Submitted to
Center for Marine Living Resources & Ecology
(DEPARTMENT OF OCEAN DEVELOPMENT)
Kochi.37
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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CRUISE REPORT – 237 (LEG I)
Environment and Productivity patterns of Indian EEZ
Cruise Track of 237 - Ist LEG
21
20
Latitude (°N)
19
18
17
16
15
67
68
69
70
71
72
73
Longitude (°E)
Diurnal Stations.
Normal Stations
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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INTRODUCTION
The cruise 237 of FORV Sagar Sampada was aimed to study Environment
and Productivity patterns, in the Arabian Sea during summer monsoon (August,
2005). In addition, data was also collected for Marine Mammals as a part of
studies conducted by Central Marine Fisheries Research Institute. This cruise
started on 10th August from Cochin with an aim of covering 17 stations in Leg I
in the northern 4 transects (21ºN, 19ºN, 17ºN and 15ºN) under
MR-LR
programme.
CTD was operated at all the stations and water samples from standard
depths were collected for the study of Physical, Chemical and Biological
parameters. Primary productivity studies were carried out by insitu incubation
(Mooring). Multiple Plankton Net (MPN) and Bongo nets were operated at all
stations to get the vertical and transverse profile of the zooplankton abundance.
Physical Oceanography
Mr. Muraleedharan.K.R
National Institute of Oceanography, Kochi.
During the first leg of cruise 237, eighteen stations were sampled in 4
transects. The major objective of this cruise was to observe the environmental
processes in the northern Arabian Sea during summer monsoon. Forty CTD
casting were recorded in a spatio-temporal scale and data was processed with a
bin average of 1m depth. The wind speed, direction and humidity were
measured using Anemometer, Psychrometer respectively. Surface meteorological
parameters including SST were measured manually and compared with the data
from automated Integrated Data Acquisition Software (IDAS).
The salinity
values from the CTD were corrected against the values obtained from the ship
borne Autosal.
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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Salient features
 Maximum Sea Surface Temperature (SST) of 28°C was observed at
coastal station of the Goa transect and minimum of 27°C was observed at
northern and offshore stations of all transects.
 Strong, westerly wind (10m/s) was recorded in the northern transect
while off Goa transect wind was weak (3m/s) and northerly in direction.
 Shallow Mixed Layer Depth (MLD) of 15m was observed at coastal
stations and deep MLD of 75m was observed at open ocean stations
 The depth of 15°C isotherm (Thermo cline) showed a strong coastal-open
variation with maximum at 265m depth in the open ocean and 175m
depth in the coastal station.
 Sea Surface Salinity showed maximum value of 36.8psu in the open ocean
waters and minimum of 34.9psu in the coastal waters.
 Atmospheric Pressure (AP) showed a strong gradient in the open ocean
stations than coastal stations. Low AP of 1000mb was recorded in the
northern transect and high AP of 1010mb was recorded at southern
transect.
 Northern transects showed high humidity above 80% and southern
transects showed low humidity below 80% during the cruise period.
Chemical Oceanography
Dr. Maheswari Nair, Ms.Josia Jacob
National Institute of Oceanography, Kochi
Around 250 water samples were collected from standard depths upto
1000 m off Veravel to off Goa using CTD rosette sampler fitted with 1.7 litres
Niskin bottles. Samples for dissolved oxygen were immediately fixed with Winkler
A and Winkler B reagents and subsequently analyzed onboard with sodium
thiosulfate solution and starch indicator using Dosimat 665 titration unit. pH was
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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estimated using PHM 84 Meter after calibrating using buffer standards of pH 7
and 9. Nutrients (Nitrate, Nitrite Phosphate and Silicate) were analyzed by
Segmented flow Auto analyzer (SKALAR) after calibration using standard
solutions and using standard procedures onboard. Samples for nitrous oxide
were collected from selected stations (off Mumbai and off Ratnagiri),
the analysis of which will be done in the lab using Gas
Chromatograph.
Salient features
 Dissolved Oxygen showed higher concentrations (>200µM) at surface
waters of all transect and this is followed by an intense oxygen
deficiency
in
the
intermediate
layers
(150-750m)
with
DO
concentrations as low as <5µM. Even the shallow shelf waters was
found to be oxygen deficient.
 The pH values in all transect ranged from 8.10 to 7.40 with maximum
values observed in surface well mixed waters (0 to 50m) followed by
minimum values in deeper layers.
 Low concentration of nutrients was observed in the surface waters (050m) of all transects (nitrate ~ 0.0 –0.5µM, phosphate ~ 0.2 - 0.8µM,
silicate 2 -3.0µm) followed by increase in concentration at intermediate
depths
reaching
higher
values
at
1000m
(nitrate~38.0µM,
phosphate~3.2µM, silicate~75.0µM). Secondary nitrite was observed
in the intermediate oxygen deficient waters (150-750m) with DO
concentrations even less than 10µM.
Biological Oceanography
Mrs. C.R. Ashadevi, Mr.H. Habeebrehman, Miss .K.J Jayalakshmi & Miss P. Jasmine
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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National Institute of Oceanography, Kochi.
Primary productivity studies
PP measurements were carried out at all transects (4), at inshore and
offshore stations (total eight).
14C
technique was followed for the productivity
studies by incubating the samples from sunrise to sunset from seven discrete
depths (surface, 10, 20, 50, 75, 100 & 120 meters). After inoculating the sample
with 1 ml of NaH14CO3 (activity 5 µC) the light and dark bottles were kept for
insitu incubation for 12 hrs. After filtering the samples through 47 mm Whatman
GF/F filters (0.7 µm) and the filters were exposed to HCl fumes to remove
inorganic carbon and kept in 8 ml capacity scintillation vials for later isotopic
analysis at the shore lab. For the estimation of chlorophyll a one-litre each of
seawater collected from the same depths was filtered through 47 mm Whatman
GF/F (with a few drops of MgCO3), and the filter preserved for its extraction in
90 % acetone and quantification using spectrophotometer. For the estimation of
Particulate Organic Carbon 1 litre of seawater (seven depths) was filtered and
the filters were stored in freeze till its analysis in shore lab by wet oxidation.
Phytoplankton Identification
250 ml of seawater was collected from each of the 7 depths at the PP
stations using CTD rosette sampler and preserved in Lugol’s Iodine solution. The
qualitative and quantitative study of the Phytoplankton will be carried out at the
shore lab.
Microzooplankton identification
8 litre of seawater collected using the CTD from the 7 depths at each of
the PP stations were sieved through 20 µm mesh and preserved in Lugol’s iodine
solution, to be analysed at the shore laboratory.
Secondary productivity studies
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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Zooplankton samples were collected from all stations by using Multiple
Plankton Closing Net (Hydro bios), Bongo Net, and WP Net.
Bongo net was operated horizontally for 10 minutes at 2 knots ship speed
at all stations for the collection of zooplankton especially for fish eggs and larvae.
After the measurement of live biomass, zooplankton samples were preserved in
4% formalin-seawater. WP Net was operated vertically from 50m to surface at
selected stations for bioluminescence studies.
MPN (mesh size 200 micron and mouth area 0.25 m2) was used for the
stratified sampling of zooplankton from five different standard water columns
(0 – TT, TT – BT, BT – 300, 300 – 500 and 500 – 1000m). The hauling speed of
MPN was limited to one meter per second. After the measurement of live
biomass, the zooplankton samples were preserved in 4 % formalin-seawater.
Salient Features
 Swarms of bioluminescent ostracods were observed off Ratnagiri at
Station no. 1720 D (Lat. 17º N; Long. 69ºE).
 Displacement volume of Bongo samples at same station (1720 D) showed
very high values (210ml and 335ml) in night collection.
 Abundance of Noctiluca sp. were observed in the surface waters along the
offshore stations in the Goa transect (15º N).
Bioluminescent studies
Pramod.S
National Institute of Oceanography, Kochi.
Eight WP Net operations were done during the first leg of the cruise 237
(Veraval – Goa). Maximum displacement volume (32ml) was obtained at station
1712, (19°04’N, 69°19’E), bioluminescent Doliolids spp were obtained at same
station. Bioluminescent Ostracod swarms were obtained at Station 1720
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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(17°00N, 69°00E) and the samples were preserved for further biochemical and
microbiological studies. Details of the station location and DV are given below.
Date
Station No
1709
Latitude
(°N)
21°00
Longitude
(°E)
69°00
Depth
(m)
206
Time
(Hrs)
22:00
DV
(ml)
20
15-08-‘05
16-08-‘05
1710
21°00
69°00
1738
22:45
30
18-08-‘05
1712
19°00
69°00
2704
22:00
32
20-08-‘05
1715
19°00
72°00
67
18:20
10
22-08-‘05
1717
17°00
72°00
118
0:35
6
23-08-‘05
1720
17°00
69°00
2538
23:00
30
25-08-‘05
1722
15°00
71°00
2590
20:00
30
28-08-‘05
1725
14°53
73°00
60
1:00
15
Microbiological Studies
Baby Divya
National Institute of Oceanography, Goa
The main objective for carrying out this work is to understand the bacterial
diversity in the oxygen minimum waters and sediments of eastern Arabian Sea.
Water samples were collected from four stations: off Veraval (20° 58’N, 68°
16’E), off Mumbai (19° 00N, 69° 00’E), off Ratnagiri (17° 00’N, 69° 00’E) and off
Goa (15° 00’N, 71° 00’E) at depths 50m and 750m. Water samples as well as
sediment samples were also collected from 1000m and 60m depths respectively
in the stations (15° 00N, 72° 45’E) and (14° 53’N, 73° 34’E). A grab was
operated for the former and box corer for the latter for sediment collection. The
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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above samples were fixed for the enumeration of total count and total viable
counts of bacteria and plated for the enumeration of colony forming units.
Further analysis would be carried out in the laboratory (National Institute of
Oceanography, Goa).
Marine Mammals
Afsal V.V
CMFRI Mandapam Camp
Survey Methods:
Watching of whales and dolphins during daylight was carried out
mainly from the bridge of the vessel. A binocular and camera were employed to
observe and capture appearance of these animals in the form of spouts, dorsal
fin, upper body, flipper, and flukes wherever possible.
The data recorded at the time of sighting were:
o Date and time of sighting
o Place (nearest landmark) and Latitude & Longitude
o Number of animals and distance from vessel
o Depth of the area
o Movement of the animals and the duration of sighting
o Weather conditions
Published pictures of whole animals, size of spouts and shape of dorsal fin and
caudal flukes of different species were used to identify the cetaceans sighted.
Only if the species of a whale or dolphin is unmistakably identified based on the
reported description, its name was recorded. In case there was a doubt the
species name was mentioned, accompanied by “possible”. All others were
treated as “unidentified”.
Result
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Preliminary report of Cruise 237 – LEG 1
Environment and Productivity patterns of Indian EEZ
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Only a school of dolphins-unidentified were sighted at an area , off
Ratnagiri (17º00N & 70º47E) on 23-08-05. Rest of the days there was no
sighting of marine mammals. The sea was moderately rough for the first 10 days
after that it subsided.
SIGHTING RECORDS OF MARINE MAMMALS
DATE
23rd
AUG
2005
TIME
GMT &
LOCAL
2:27
7:57
LAT
LONG
(°N)
(°E)
& 17º00
70º47
Place:
Goa
Date:
29th Aug. 2005.
AREA
Off
Ratnagiri
DEPTH
(m)
270
SPECIES
REMARKS
Dolphinsunidentified
5-6 individuals were
observed at 11ºclock
position & about 100
m away from the
vessel, only for one
minute.
Moving
westwards along the
vessel. Dark gray in
colour. Weather was
cloudy
Dr. Maheswari Nair
Chief scientist Cr. No. 237 (Leg 1)
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Preliminary report of Cruise 237 – LEG 1