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analysed after acidification by titration against standard sodium thiosulphate using starch as indicator. The concentration of oxygen in the sample was calculated as, Dissolved oxygen (mill) = 5.6*N*(S-Bm)* VI V-l)*lOOOIA Where. N = Normality of thiosulphate in solution S = Titre value for sample Bm = Mean titre value for blank V = Volume of the sample bottle 2.2.2 Sediment and benthic samples A = Volume of sample titrated (50 ml) Sampling was done for the estimation of sediment parameters like texture and organic matter and for macro and meiobenthos from all the stations. A total of 48 grab samples (23 from post-monsoon season and 25 from pre-monsoon season cruises) were collected for the present work. Modified Smith Mc lntyre Grab was used for collecting sediment samples (Plate 3). It traps a substantial volume of sample, as its open mouth covers a surface area of 0.lm2. During the sampling. the vessel was maintained stationary and the wire was kept as vertical as possible to ensure vertical set down and lift-up of the grab at right angles to the hottom. As recommended (ICES, 1994). the final 5 m of descent was maintained at a rate < 0.5 m.s- I to minimize the shock bow wave disturbances. The sample showed a distinguishable undisturbed surface layer. often including loose flocculent deposits and no sign of sediment leakage, such as from incompletely closed buckets. Approximately 150 gm of wet sediment sample from each station was taken and dried onboard the ship at 70° C in an oven and stored in the polythene bags for the study of sediment characteristics. The dried samples were taken to the laboratory for further analysis. 24
2. 2. 2. 1. Macrobenthos After sub sampling, all the samples remaining in the grab were sieved through O.5mm (SOO J!) sieve to separate specimens from the substrate. For unloading the sediment from the grab and then sieving, a wooden platform was fabricated (Plate 4). The sediment was unloaded in the conical aluminum portion of the platfonn, which was attached to the upper frame. The lower frame was modified in such a way so as to slide in and out the sieve in the form of a drawer, where the sediment unloaded as directly collected in the sieve. For the present study, O.S mm sieve was selected for separating macro benthos. In order to avoid sample degradation, the sieving was accomplished on board soon after the sample collection. It was done by washing the sample with seawater in a bucket and then sieving using SOOJ! sieve. Since immediate processing for taxonomic study is not possible, sieved specimens and residual sediments were transferred to plastic bottles and fixed in S% neutral fonnaldehyde with "Rose Bengal" for staining the live organisms. Samples were properly labeled with details like cruise number, date, time, station position and depth. 2.2.2.1. Meiobenthos At each station, with the help of a glass corer (2.S cm diameter), sediment samples of 10 cm long cores were drawn and length of the core measured. Replicate (in some cases only one) sub samples were collected from each haul. The samples in Toto were transferred to polythene containers, labeled and material preserved in 70% alcohol-Rose Bengal solution for further examination. On arrival at the shore laboratory, the sediment samples were processed through a set of two sieves, the upper one of SOOJ! and the lower with 63Jl. Residue retained over 63 J! sieve was back washed into a glass container and the same preserved in 70% alcohol or 4% neutral formalin. In some cases, Rose Bengal was 25
Page 2 and 3: Certificate I hereby certify that t
Page 4 and 5: Contents Page No. Chapter 1. Introd
Page 6: the bottom. Ekman (1935) described
Page 9 and 10: wonns are the most abundant group a
Page 11 and 12: leadership of Sir James Clark Ross,
Page 13 and 14: Ansari et al., (1977b) carried out
Page 15 and 16: Gopalakrishnan and Nair (1998) cond
Page 17 and 18: Major objectives:- 1. To understand
Page 19 and 20: CMFRI (Central Marine Fisheries Res
Page 21 and 22: Joydas, T.V., Damodaran, R., 2001.
Page 23 and 24: monitoring committee (Atlantic Mari
Page 25 and 26: Vizakat Lathika, I-Iarkantra, S. N.
Page 30: used as stain prior to sorting and
Page 33 and 34: space. Therefore, it is very essent
Page 36 and 37: Fig. I - Station locations 32
Page 39 and 40: affected at high temperature. Most
Page 41 and 42: layers exhibit different oceanograp
Page 43: Transect wise variation in temperat
Page 46 and 47: 3.2.2.3. Dissolved oxygen (DO) Dist
Page 48 and 49: monsoon temperature initially incre
Page 50 and 51: opined that limited mixing. high or
Page 52 and 53: Naqvi, S. W. A., Noronha, R. J., Re
Page 56: orr Mormugao orr Vernal 35.36 35.32
Page 62 and 63: The continental shelf and its adjoi
Page 64: sediments (4 stations). Silty sand
Page 68 and 69: fine sediments with comparatively h
Page 70 and 71: Narayana, 1991 ). Limited input of
Page 73 and 74: In general. two ditlerent patterns
Page 75 and 76: et al., (1980) reported values in t
Page 77 and 78:
organisms living in the water and t
Page 79 and 80:
Hashimi, N. H., Kidwai, R. M., Nair
Page 81 and 82:
Postma, H., 1967. In Estuaries, Lau
Page 85:
Depths Sand Silt Clay Organic matte
Page 90:
• PRE'MONSOON SOUTHERN'TRANSECTS
Page 96 and 97:
as the best indicators of the envir
Page 99 and 100:
showed that northern transects have
Page 101 and 102:
decreased from shallow to deeper de
Page 103:
different depth zones showed that a
Page 106 and 107:
cm 2 with a dominance of nematodes.
Page 108 and 109:
and 6.08 g/m 2 were recorded during
Page 110 and 111:
were located in the nearshore water
Page 112 and 113:
changes in the hydrographical and t
Page 114 and 115:
factor for such a large difference
Page 116 and 117:
Belegvad, H., 1932. Investigations
Page 118 and 119:
Parulekar, A. H., Harkantra, S. N.,
Page 120:
Savich, M. S., 1972. Quantitative d
Page 123 and 124:
Traosects Polychaetes Crustaceans M
Page 125:
Miscellaneous Transects Nematodes C
Page 128 and 129:
Depths Nematodes Cope pods Foramini
Page 136 and 137:
Wagh, 1975; Parulekar et ai, 1976;
Page 138 and 139:
ones and 17 were included in the 'r
Page 140 and 141:
Nephtydae (2%). Among the 20 sedent
Page 143 and 144:
At 75 m zone, 31 groups/species wer
Page 145 and 146:
Porbandar. At 50 m depth zone, fluc
Page 148 and 149:
otTMumbai and Ratnagiri and low eve
Page 150 and 151:
species richness at each depth zone
Page 153 and 154:
E2.2.2.!. Richness (Margalef's inde
Page 155:
I ):.2.2.2.4. Dominance (Pie/ou's i
Page 172 and 173:
Tablc 17. Contd .. - Sternaspidae 0
Page 176:
Table 20. contd .. G. alba 20 25 20
Page 179:
150 Taxa 30m 50m 75m lOOm 150 m m D
Page 186:
9% 1% o poIychaete • crustacea o
Page 203 and 204:
a) c) e) g) Plate 5 a) Prinospio sp
Page 205 and 206:
a) c) e) Plate 7 a) Cardium sp. d)
Page 207 and 208:
7/. /ntroduct ion 7.2. Hydrography
Page 211 and 212:
also showed a similar pattern with
Page 213 and 214:
y most of the organisms. It was als
Page 215 and 216:
with sand of which total density (r
Page 217 and 218:
muddy bottom of the west coast of I
Page 219 and 220:
crustaceans and miscellaneous group
Page 221:
the organic rich environment with h
Page 225 and 226:
Icvci (p
Page 227 and 228:
mcioHmna serve primarily as rapid m
Page 229 and 230:
surface chlorophyll a was 0.36mg I
Page 231 and 232:
Devassy, V. P., Achuthankutty, C. T
Page 233 and 234:
Longhrust, A. R., Pauly, D., 1987.
Page 235 and 236:
Sikora, W. B., 1977. The ecology of
Page 237:
Faunal groups Silty Clayey Mixed Sa
Page 257:
Mannagoa to Porbandar located betwe
Page 260 and 261:
against gastropods during pre- mons
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