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Figure 74 – uploaded by Goldin Quadros

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Fig Ma-6a: Stationwise variations in the density (no/m2) dominate the community (Remani et al., 1983). sensitive organisms will be eliminated and successful organisms increase in number to excludes other species, reducing the diversity. Furthermore, under stress conditions the — Figure 74 Ma-6a: Stationwise variations in the density (no/m2) dominate the community (Remani et al., 1983). sensitive organisms will be eliminated and successful organisms increase in number to excludes other species, reducing the diversity. Furthermore, under stress conditions the

Related Figures (204)

at 70° C and analysed for the following.

was collected using a wide mouth container from a depth 1 foot from the surface.

plotted the hypothetical curves as shown in the figure ahead.

Table T-1 Monthly variations in water temperatures °C at different stations during high tide. °C (i.e. 13°C Murugan & Ayyakkannu, 1991), which is comparable to the present study.

Fig T-1 : Monthly variations in the atmospheric temperature and the overall average water temperature (°C Thane city during the period 1991 - 93

Table T-2 Monthly variations in water temperatures °C at different stations during Low tide.

Fig T -2: Station wise variations in atmospheric and water temperature (°C) during High tide and Low tide

Table T-3 : Comparison of water temperature (°C) ranges with the past data.

Fig T -3 : Comparison of the average water temperature data of Thane creek with that of the past.

Table Lp-1: Monthly variations in light penetration (cms) at different stations during high tide. Hooghly estuary (Quadros, 1995). Wide range of light penetration is a common feature of several Indian estuaries. (Mishra et al., 1993). Table Lp-2: Monthly variations in light penetration (cms) at different stations during low tide

Fig. Lp-1 : Monthly variations in the average light penetration (cms) during high tide and low tide. Lp-1). whereas improved production from January to April reduced the light penetration (Fig.

Fig. Lp-2 : Stationwise variations in the average light penetration (cms) during high tide and low tide.

Table SS-1: Monthly variations in suspended solids (gm/1) at different stations during high tide Table SS-2: Monthly variations in suspended solids (gm/l) at different stations during low tide

Fig SS-1 : Monthly variations in the average suspended solids (gm/1) during high tide and low tide observation during 1991-93 in the upper stretch of Thane creek.

Fig SS-2 : Stationwise variations in the average suspended solids (gm/l) during high tide and low tide.

Fig. SS-3: Comparison of suspended solids of the past and entire length of the creek and were not restricted to the marine end.

Table pH- 1: Monthly variations in pH at different stations during high tide

Fig. pH-1 : Monthly variations in the average pH during high tide and low tide. higher and in the later period it was lower. December to March. It is probable that in the earlier period photosynthetic activity wa

Table pH- 2: Monthly variations in pH at different stations during low tide 5.9, whereas Gouda & Panigrahy (1993), reported pH upto 9.1 in the Rushikulya estuary.

Fig pH-2 : Stationwise variations in the average pH during high tide and low tide. freshwater flow from the Ulhas river has got reduced significantly. the creek has become shallow due to reclamation activities. Due to these reasons the

Fig. pH-3: Comparison of annual average pH with

Table Sl-1: Monthly variations in salinity (ppt.) at different stations during high tide Table Sl-2: Monthly variations in salinity (ppt.) at different stations during low tide

Fig Sl-1 : Monthly variations in the average salinity (ppt.) during high tide and low tide. monsoon, only October showed intermediate salinity followed by rise up to 25 ppt. in November. Salinities more than 35ppt. or even 40 ppt. were also evidenced sporadically. According to Cyrus (1986) it is not unusual for some creeks and estuarine systems to reach salinity levels above that of the sea. However, the monthly average salinities in the present-study did not exceed 35 ppt. The post monsoon salinities were in range 25 to 32.9 ppt (Fig. Sl-1) indicating moderate dilution of the incoming seawater which could be due to 145 -260 mld sewage effluents and 15-20 mld industrial effluents from Thane city (TMC-ES report, 2000) and additional from Mumbai suburbs and New Mumbai area along with minor riverine fresh water flow. along with minor riverine fresh water flow.

Fig Sl-2 : Stationwise variations in the average salinity (ppt.) during high tide and low tide

which steadily increased to 28 ppt. at stn 12. on the seaward side. In most estuaries and creeks ebb tides experience lower salinities than flood tides. In the present study the difference between average high tide and low tide salinity was insignificant due to dominance of marine water and homogenous mixing. Low salinities on the riverine end is a common feature of estuaries. Nair & Abdul Aziz (1987), observed that the salinities progressively decreased from the mouth to the riverine end in Asthamudi estuary. Similar observations were made by Alam (1992) and Athalye ( 1988) in the Malad creek and Thane creek respectively. In the present investigation also similar trend was observed (Fig. Sl-2). Average salinity at stn 1. on the riverine side was 11 ppt. which steadily increased to 28 ppt. at stn 12. on the seaward side.

Table D-1: Monthly variations in dissolved oxygen (mg/l) at different stations during high tide

Table D-2: Monthly variations in dissolved oxygen (mg/l) at different stations during low tide

Fig. D-1: Monthly variations in the average dissolved oxygen (mg/l) during high tide and low tide.

Fig. D-2: Stationwise variations in the average dissolved oxygen (mg/l) during high tide and low tide.

Fig. D-3: Comparison of the annual average dissolved oxygen

Table P-1: Monthly variations in Phosphate-Phosphoms (mg/l) at different stations during high tide. Table P-2: Monthly variations in Phosphate- Phosphorus (mg/1) at different stations during low tide.

Fig. P-1: Monthly variations in the average Phosphate Phosphorus (mg/l) during high tide and low tide. upstream stretches of Thane creek. A tide wise comparison revealed marginally higher averages of PQ,-P during high tide than low tide. However, the difference was not significant. Similar observation has been recorded by Qasim & Gopinathan (1969), in Cochin backwaters and Singbal (1973) in Zuari estuary. In contrast higher P04-P values during low tide have been recorded by Alam (1992), in Malad creek; Dehadri (1970), for Zuari & Mandovi estuaries; Vijayalakshmi & Venugopalan (!973), for Zuari estuary and Quadros (1995) for the upstream stretches of Thane creek. The seasonal variations (Fig P-1) indicated lower P0.-P during the monsoon season followed by an increasing trend from October to May. Lowering of PQ.-P during monsoon has been recorded in some estuaries like Mahanadi, Hooghly estuary, Periyar estuary & Netravati estuary by Upadhyay (1988), Vaithiyananthan et al. (1993), Sarala Devi et al. (1991) & Nagarajaiah & Gupta (1983) respectively. The low monsoon phosphate was attributed to high sediment load during the rainy season favoring

Fig. P-2: Stationwise variations in the average Phosphate -Phosphorus (mg/l) during high tide and low tide. more diluted leading to a decreasing trend towards the sea.

Nitrate nitrogen (N03-N).

Table N-1: Monthly variations in Nitrate-Nitrogen (mg/l) at different stations during high tide. Table N-2: Monthly variations in Nitrate-Nitrogen (mg/l)at different stations during low tide.

of high tide & Low tide did not differ significantly. Fig.N-1: Monthly variations in the average Nitrate- Nitrogen (mg/l) during high tide and low tide.

Fig.N-2: Stationwise variations in the average Nitrate-Nitrogen (mg/l) during high tide and low tide.

‘ig. N-3: Comparison of the annual average NO3-N data with the pa comparable data for the upper stretches of Thane creek. Fig.N-4: Comparison of the annual average NO3-N data with the pas comparable data for the downstream stretches of Thane creek stretches of Thane creek.

Table Si-1: Monthly variations in Silicate-Silicon (mg/l) at different stations during high tide. the low monsoon values can be attributed to dilution caused by fresh water influx. According to Biggs & Cronin (1981) in Indian estuaries silicates show a strong pulse during

Table Si-1: Monthly variations in Silicate-Silicon (mg/l) at different stations during Low tide.

Fig.Si-1: Comparison of SiO3-Si with the past

Fig. Si-3: Stationwise variations in the average Silicate-Silicon (mg/l) during high tide & low tide.

Table S - 1: Review of the sedimentology studies done in foreign countries. discussion on sedimentological studies of the intertidal mud flats of Thane creek.

Moisture Content ihe amount or water present in the sediment at any given time 1s called the moisture conten of that sediment. In source of water to th water holding capaci (1936), clay fraction organic carbon. The marine ecosystems, tidal waters, land runoff and rainfall form the mair e sediments. Presence of clay in the sediment is known to increase the ty, whereas sandy substrates hold less moisture. According to Robinsor is of colloidal character having high holding capacity for water anc moisture content also depends on the pore space; the presence of organic matter reduces the compactness of the soil and increases the porosity.

Table Mc-1: Monthly variations in moisture content (%) at different stations. matter reduces the compactness of the soil and increases the porosity. which had more sand in its substratum. The sediment at station 5 in general had high

Fig.Mc-1: Monthwise variations in the average moisture content (%). reported by Elster et al. (1999) for Sunderban mangroves and Colombia mangroves

Fig Mc-2: Stationwise variations in the average moisture content (%).

Table ST-1- : Review of sediment quality from different water bodies. ) be clayey-silt in 1991 - 93. They attributed this destabilization of substratum to extensive

Table ST-2: Monthly variations in Coarse sand (%) at different stations.

Table ST-3: Monthly variations in Fine sand (%) at different stations.

Table ST-4: Monthly variations in Silt (%) at different stations.

southward (1957) is of the opinion that the rains are the controlling factor of the nature of leposit. Matilal et al. (1986) observed coarse sand content in the mangrove forest o! sunderbans which they attributed to gradient factor and consequent increase in the rate of edimentation in riverbeds. Seasonal variations were also observed at Versova by Varshney t al (1984). In the present study silt and clay showed monthly fluctuations antagonistic to ach other, maintaining overall fine sediment percentage constant. Fine sand showed

period whereas coarse sand was never more than 0.7 % (Fig ST-1 to 4). Fig ST-1: Monthly variations in the average Fig ST-2: Monthly variations in the average Fine Coarse sand component (%).

showed an exactly opposite trend to that of the silt. Fig ST-6: Stationwise variations in the average Fig ST-5: Stationwise variations in the average the seaward station 10 and marginally increased at the extreme seaward zone. Clay at all the other stations it was negligible. Silt showed a marginal decline from the river till

Fig. ST-9 : Comparison with the past comparable data for the shallow region of Thane creek.

Table SpH-1: Monthly variations in sediment pH at different stations. Table SpH-2: review of pH from different water bodies.

was more alkaline indicating dominance of neritic waters in the creek influencing the

Fig SpH-2: Stationwise variations in the average sediment pH. between the sampling stations. However, excluding station 2, the general trend showed

Table Cl-1: Monthly variations in sediment Chlorides (%) at different stations. average (1.12 to 4.28 % av. 2.7%) was also reported by Ukpong (1997) for the Calabar

Fig Cl-2: Stationwise variations in the average sediment Chlorides (%). end to the seaward end (i.e. Station 1 to station 12.).

Table Eh-1: Monthly variations in sediment redox potential (mV) at different stations. Luoma & Bryan (1981) only the oxidized surface layer of sediment readily interacts with

Fig Eh-1: Monthly variations in the average sediment redox potential (mV). yre monsoon could have resulted from the harsh environmental conditions and effluent even through some part of the post monsoon. The strongly reduced conditions during the

Fig Eh-2: Stationwise variations in the average sediment redox potential (mV). A stationwise average (Fig. Eh-2) comparison revealed more reduced sediments at the

Table OC-1 Review of % organic carbon from different water bodies.

Table OC-2: Monthly variations in sediment organic carbon (%) at different stations. productivity of water and degradation of organic matter by organisms. Further, seasonal

Fig OC-1: Monthly variations in the average sediment organic carbon (%). Fig OC-2: Stationwise variations in the average sediment organic carbon (%).

Fig. OC-3: Comparison of organic carbon (%) with the past comparable data.

Table TAP-1- : Review of literature on Total Phosphorus (%) Table TA P-2: Monthly variations in sediment Total Phosphorus (%) at different stations. quatic ecosystems is presented in Table.TA P-1

Table TAP-3: Monthly variations in sediment A vailable Phosphorus (%) at different stations. percentage or fine-grained sediment than Sand, which according to Nair et al. (l¥o/) 1s responsi minimu minimu verlyin ) physica ( ble for higher percentage of organic carbon and phosphorus. The maximum an m values of total phosphorus were observed during the monsoon. Whi available phosphorus was maximum during summer and minimum during monsoo m values can be attributed to leaching of phosphorus from the mud g waters (Sankaranarayanan & Punnampunnayil, 1979) and sudden unstab le th n. Th to. th d € € € € structure of the sediment (Nair et al., 1983). Further, according to Rochford 951), total phosphorus is maximum in both freshwater and marine zones althoug h their derivatives are different in these zones. This is also true in case of Thane creek where high and fluctuating total phosphorus was recorded.

sediment Total phosphorus (%).

Table TN-1: Monthly variations in sediment Total Nitrogen (%) at different stations.

high values during the pre monsoon and attributed them to the oxidation of mangrove

Fig TN-2: Stationwise variations in the average sediment Total nitrogen (%). A stationwise comparison (Fig. TN-2) revealed high which gradually reduced towards the sea. Corroborati total nitrogen at the riverine end ng with the observation of Nair et al. (1983) for Asthamudi estuary, who attributed high organic carbon as the reason fo1 high riverine total nitrogen. In the present study to positive correlation with silt (r =0.1839) and sedimen tal nitrogen showed a significant t organic carbon (r =0.5847). The other significant correlations were with water parameters pH (r =0.1950), dissolved oxygen (r = -0.2666), PO4-P (r = 0.5212), Si03-Si (r = 0.6255) and with sediment parameters pH (r =0.3383) & available phosphorus (r =0.3194).

Table P-1: Review of phytoplankton study around the world.

Table P-2: Monthly variations in total Phytoplankton number (cells x 10°/1) during high tide.

Table P-3: Monthly variations in total Phytoplankton number (cells x 10°/1) during low tide. comparable only to Pamlico river estuary (Hobbie, 1971).

Table P-4 : Review of phytoplankton densities from different water bodies.

Fig. P-1 : Monthly variations in phytoplankton (no x 10°/l)during high tide and low tide. receives domestic and industrial effluents in large quantities and showed similar trend as

Table P-6: Simple correlation coefficients of dominant phytoplankton with water parameters. phytoplankton and the total phytoplankton are presented in Table P-6.

during high tide. A stationwise comparison (Fig P-2) revealed in general higher density and species number at the upstream riverine end than the downstream seaward end during low tide, which could be due to higher sewage pollution in the upstream region providing high amount of nutrients for phytoplankton growth. The density during high tide showed an increasing trend from station 1 to 6 and thereafter declined up to station 12. During high tide probably the phytoplankton from the downstream stretches probably get pushed upstream, thus increasing their number at these stations. Whereas at the downstream stations large quantity of neritic water has a diluting effect, thus giving a different trend a ey el es fone stations large quantity of neritic water has a diluting effect, thus giving a different trend

Table P- 7: Diversity indices for phytoplankton during high tide and low tide. correlation with salinity corroborating with the above view.

Fig P- 3: Comparison of phytoplankton number

Table Z-1 : Monthly variations in total Zooplankton number (no/m3) and biomass (ml/m3). Table Z-2 : Review of Zooplankton density and biomass average values.

Table Z-3 Stationwise occurrence and distribution of zooplankton (no/m3).

stations can be attributed to the high saline regime where the zooplankton flourish (Rao et increasing trend towards the sea (Fig Z-2). This increasing diversity at the seaward compared to the seaward end, but the number of dominant species (N 1 & N 2) showe

Table Z-4: Correlation coefficients of zooplankton with environmental parameters.

Fig Z-2 : Stationwise variations in the total number (N 0), dominant number (N 1)

and most dominant (N 2) number of zooplankton. Fig Z-3 : Monthly variations in the density of zooplankton (no/m3).

Hence a correlative study on zooplankton distribution, their intensity and seasonal

Fig Z-4 : Comparison of stationwise diversity (H’ & A) indices and Eveness (E 5) index. indicated increasing diversity and evenness indices towards the seaward zone 5. episodic pulses in their abundance. The diversity indices in the present study (Fig Z-4) reduce the species diversity and increase population sizes of tolerant species causinc¢

cogent reasoning with respect to the tropical estuaries pertains to the lack of stability.

Fig Z-6 : Comparison of the present zooplankton density (no/m3) with the past available data obtain fish yield, corroborating with the concern raised by Varshney et al. (1982-83). Summary.

Table Mp-1 : Monthly variations in the microphytobenthic number (no/cm2) at different stations. Table Mp-2: Stationwise distribution of different microphytobenthos (no/cm2) investigation.

Fig Mp-1: Stationwise variations in the microphytobenthos no/cm2. heterotrophic uptake of organic material might be of significance in interface processes nitrogen uptake associated with all microalgae, nitrogen fixation by cyanobacteria and presence of these other taxa suggests that in addition to the production, oxygen flux anc

In shallow aquatic ecosystems, a variety of physical, chemical and biological factors may regulate the standing stock of microphytobenthos, hence according to Cahoon et al.

Table Mp-3: Simple correlation coefficients of microphytobenthos with environmental parameters abundant evidence of their importance in the marine food chain suggests that microalgae

Table Me-1: Monthly variations in the abundance of meiobenthos at different stations (no/m7) intertidal mudflats of the upstream region of Thane creek. The present study is the first account of the meiobenthos from the intertidal region of the entire stretch of Thane creek. vere recorded at station 5 and station 9 respectively in December while the maximum

Table Me-2: Monthly variations in the biomass of meiobenthos at different stations (gm/m? wet wt.).

Table Me-3 : Review of meiofauna from different water bodies

Fig.Me-1: Stationwise variations in the annual average meiobenthic abundance (no/m’) and biomass (gm/m?

Fig.Me-2: Monthly variations in the annual average meiobenthic abundance (no/m’) and biomass (gm/m?)

Table Me-4: Stationwise variations in the annual average occurrence (no/m’) of different meiobenthic groups. Nematoda

Table Me-5: Monthly variations in the Nematode density (no/m7) at different stations. Foraminifera Benthic foraminifera are heterotrophic, amoeboid protozoa, characterized by the presence of granulo reticulose pseudopodia and a test (shell) with one or more chambers (Moodley et al., 2000) Foraminifera are prevalent members of the benthic meiofauna (Y ingst, 1978). T hey are widespread and have colonized a wide range of habitats since their first appearance in the Cambrian. Because of the fossilization potential of foraminifera, most of the studies have been carried by geologist, leading to a vast literature on shel taxonomy and broad-scale distribution patterns (Boltovskoy & Wright, 1976; Murray, 1991). In recent years, foraminifera have been increasingly found to be dominant members of benthic communities in both shallow and deep sea environment (Widbom, 1988; Alongi, 1992; Moodley et al., 2000). According to Moodley & Hess (1992

Table Me-6: Monthly variations in the foraminiferan density (no/m’) at different stations

Table Me-7: Monthly variations in the Oligochaete density (no/m?) at different stations

Table Me-8: Monthly variations in the Polychaete density (no/m’) at different stations

Table Me-9 : Simple correlation coefficients of meiobenthos with environmental parameters.

action at station 12. the higher sewage load at stations 1 to 5 & 9 and disturbance caused by stronger wave

Fig.Me-4: Stationwise variations in the richness indices Margalefs’ (R 1) and Menhinick (R 2)

Fig. Me-5: Stationwise variations in the diversity indices

The abundance biomass curve (ABC curve) as suggested by Warwick (1986) is a simp lution. As explained in Chapter I (Fig I -1) when the abundanc mM roups of idakovic ethod of detecting po and biomass curves a abundance curve it indicates healthy conditions. While the opposite condition revea ross pollution and when the curves are placed close to each other and ev Thane creek eiofauna. versity of it suggests re placed wide apart, with t. moderate pollution. The ABC reveals moderate pollution in t (1983) pollu tion plays a major role in con he biomass curve lying over th curve plotted for the meiobenthi he creek (Fig Me-7). According t en intersect Oo Oo OD S C O trolling density and distribution of He further added that sewage tends to increase density and decrease the meiofauna, which corroborates with the present study.

A comparison of the present data with the past available data from the shallow region of Thane creek is shown in figure Me-8 which reveals that the meiofaunal density has reduced by 10 %. This reduction can be attributed to the excess organic pollution in the shallow region. This according to Warwick (1981) can be ascribed to the response ot! meiofauna to pollution much before it becomes obvious visually. Varshney et al. (1984 also reported low meiofaunal density at the creek station off Versova in comparison tc he offshore region and attributed it to greater pollution stress with which corroborates he present observation. the offshore region and attributed it to greater pollution stress with which corroborates

document the intertidal fauna of the entire 26 km stretch of Thane creek. While the remaining studies dealt with the subtidal fauna, making it necessary to

Table Ma-1a: Stationwise variations in the monthly macrofaunal density (no/m2).

Table Ma-1b: Stationwise variations in the monthly macrofaunal biomass (gm/m2).

Table Ma-2 : Review of macrofaunal density (no/m2) and biomass (gm/m2 wet wt.).

Fig Ma-2: Stationwise variations in the annual average abundance (no/m2) and biomass (gm/m2). seaward end. Similar trend was reported from Vashishti estuary, Narmada estuary, Kali

reducing the production in general.

Table Ma 2 a: Stationwise occurrence of different macrofaunal organisms (no/m2). et al., 1986).

Table Ma 2 a: Stationwise occurrence of different macrofaunal organisms (gm/m2 wet wt.).

Table Ma-3a: Stationwise variations in the total polychaete density (no/m2). Table Ma-3b: Stationwise variations in the total polychaete biomass (gm/m2 wet wt.).

"ig. Ma.-5b: Stationwise variations in the total macrobenthos and polychaete biomass (gm/m2). Fig. Ma.-5a: Stationwise variations in the total macrobentho: and polychaete density (no/m2). Fig. Ma.-5b: Stationwise variations in the total macrobenthos Fig. Ma.-5a: Stationwise variations in the total macrobenthos and polychaete biomass (gm/m2). and polychaete density (no/m2).

Fig Ma-7b: Monthly variations in the density (no/m2) and biomass (gm/m2) of polychaete Nereis glandicincta. Fig Ma-7a: Stationwise variations in the density (no/m2) Fig Ma-7b: Monthly variations in the density (no/m2) and biomass (gm/m2) of polychaete Nereis glandicincta. and biomass (gm/m2) of polychaete Nereis glandicincta.

that help them in surviving and increasing their number.

sensitive to extreme temperatures. Fig Ma-10a: Stationwise variations in the density (no/m2) mainly in pre-monsoon (Fig Ma-10b) which was probably its breeding season. Its lower Fig Ma-10b: Monthly variations in the density (no/m2) and biomass (gm/m2) of polychaete D endronereis heteropoda

Table Ma-4a: Station wise variations in the total bivalve density (no/m2). Table Ma-4b: Station wise variations in the total bivalve biomass (gm/m2 shell free wet wt.)

Fig Ma- 11a: Station wise variations in the total macrobenthos and bivalve biomass(gm/m2). Fig Ma- 11a: Station wise variations in the total Fig Ma- 11a: Station wise variations in the total

macrobenthos and bivalve biomass(gm/m2).

Fig Ma- 13a: Stationwise variations in the density (no/m2) and biomass (gm/m2) of bivalve Cardium asiaticum. “ig Ma- 13b: Monthly variations in the density (no/m2) an biomass (gm/m2) of bivalve Cardium asiaticum Fig Ma- 13b: Monthly variations in the density (no/m2) and Fig Ma- 13a: Stationwise variations in the density (no/m2) biomass (gm/m2) of bivalve Cardium asiaticum and biomass (gm/m2) of bivalve Cardium asiaticum.

Fig Ma- 15a: Stationwise variations in the density (no/m2) and biomass (gm/m2) of bivalve Katelysia marmorata. Fig Ma- 15b: Monthly variations in the density (no/m2) an biomass (gm/m2) of bivalve Katelysia marmorata. ig Ma- 15b: Monthly variations in the density (no/m2) and Fig Ma- 15a: Stationwise variations in the density (no/m2) occurred from station 7 to 12 throughout the year except monsoon (Fig.Ma -15). biomass (gm/m2) of bivalve Katelysia marmorata.

Fig Ma- 16b: Monthly variations in the density (no/m2) and Fig Ma- 16b: Monthly variations in the density (no/m2) and biomass (gm/m2) of bivalve Brachyodontes karachiensis

lam was abundant in the post monsoon season

Table Ma-5a: Stationwise variations in the total gastropod density (no/m2). Table Ma-5b: Stationwise variations in the total gastropod biomass (gm/m2 shell free wet wt.).

Fig. Ma.-18b: Stationwise variations in the total gastropod Fig. Ma.-18a: Stationwise variations in the total gastropod

Govindan et al. (1976), observed uneven distribution of gastropods in Thane creek while Mukherji (1993) reported the gastropods to be opportunistic, making erratic appearance only under favourable conditions. During the present study a total of 24 gastropod species were recorded (Table Ma-2a &b). However only 6 species were dominant in terms of abundance viz., Stenothyra deltae (av. 3256 no/m2 & 5.234gm/m2), Littorina vernuculatum (av.1221no/m2 & 1.321gm/m2), Stenothyra minima (av. 1059.58 no/m2 & 1.748 gm/m2), Assiminea brevicula (av. 567.6no/m2 & 1.35 gm/m2), Cerethidea cingulata (av.166.53 no/m2 & 47.68 gm/m2) and Thiara spp. (av. 90.69 no/m2 & 0.08 gm/m2) of these only 3 species were observed throughout the creek i.e., Stenothyra deltae, Stenothyra minima and Assiminea breviculla. The gastropods that significantly

Table Ma- 6a: Stationwise variations in the total insect larval density (no/m2). Insects Larvae

Table Ma- 6b: Stationwise variations in the total insect larval biomass (gm/m2).

extreme tolerance as it survived for 15 days in 10 % formalin solution. Fig. Ma.-20b: Monthly variations in the total insect larval Fig. Ma.-20a: Stationwise variations in the total insect larval probably proliferated at these stations. Among the 4 larvae, a maggot type larva showed

Fig Ma-7a: Stationwise variations in the oligochaete density (no/m2). Fig Ma-7b: Stationwise variations in the oligochaete biomass (gm/m2).

Table Ma- 8a: Stationwise variations in the total crustacean density (no/m2).

Fig. Ma.-21a: Stationwise variations in the density (no/m2) and biomass (gm/m2) of the crab Illyoplax gangetica. Fig. Ma.-21b: Monthly variations in the density (no/m2) and Fig. Ma.-21a: Stationwise variations in the density (no/m2)

Table Ma-9a: Stationwise variations in the total sea anemone density (no/m2) Table Ma-9b: Stationwise variations in the total sea anemone biomass (gm/m2) Sea anemones number, which can be held true for Thane creek also.

Month wise trend (Fig. Ma-22 b) showed fluctuations throughout the year. Fig. Ma.-22a: Stationwise variations in the density (no/m2) end at stations 1, 3 & 6. whereas in the lower stretches larger anemones were dominant anemones was not uniform. High abundance of small anemones was observed on riverine biomass (gm/m2) of the Sea anemones.

Table Ma-10a: Simple correlation coefficients of dominant macrofaunal species with the water parameters.

Table Ma-10b: Simple correlation coefficients of dominant macrofaunal species with the soil parameters, plankton & benthos.

& R 2 were not concurrent with actual pollution status of the station. Fig. Ma-23: Stationwise variations in the total number of species (N 0), number of dominant species (N1) and number of most dominant species (N 2). Fig. Ma-23: Stationwise variations in the total number of species (N 0), number of dominant species (N1) near sewage reach (station 5) R 1 was low & R 2 was high. Thus the fluctuations in R !

Fig. Ma-24: Station wise variations in the richness indices Margalefs’ (R 1) and Menhinick (R 2).

Fig. Ma-27: The ABC curves using the entire data of the present study Ma.-27 to 40). All the plots indicate stressful conditions in the creek.

Fig. Ma-29: TheABC curve for Station 1.

Table B-1: List of birds observed from the intertidal mudflats of the Thane creek. creek can be attributed to excess pollution and anthropogenic activities. ynset of monsoon. The reason for the absence of flamingoes in the upper stretches of the

Metabolic index

Table Pr-1: The Stationwise variations in benthic metabolic index for Thane creek. The station wise and monthwise metabolic indices & the ratios for Thane creek are shown in Table Pr-1 & 2.

Table Pr-2: The Monthly variations in benthic metabolic index for Thane creek. with the findings in the earlier chapters.

Annual production estimates. Table Pr.3: Station wise annual production estimates (gm/m2 wet wt.)and percentage contribution of macrofauna and meiofauna.

estimates calculated for Thane creek are presented in Table Pr-3. from which it is evident

Table Pe-1: Pollution limits for water and soil parameters. (Mainly creeks and estuaries or coastal environments. Sopepod index, Lampshed’s K-dominance curve, Warwick’s ABC curve, etc. But for é 10n-biologist these indices would seem to be equally difficult as the statistical anc viological indices. Hence in the present dissertation the author aims at evolving a simple -ollution Evaluator Index for assessing the health of an ecosystem. The tool is based or he standard pollution limits of aquatic ecosystem for different water & soil parameters, suggested by various researchers (Table Pe-1). Pollution Evaluator Index for assessing the health of an ecosystem. The tool is based o1 biological indices. Hence in the present dissertation the author aims at evolving a simple The procedure for calculating the index is as follows:

Table Pe-3.:Stationwise averages of various parameters and the corresponding calculation of the Pollution Evaluator Index (PED) fear was later confirmed by Athalye (1988) when he suspected stressed environmenta

Table Pe-4: Comparison of the past data of Thane creek using the pollution evaluator index Evaluation of other indices using PEI. result would be of help in arriving at a correct and unbiased conclusion.

Table Pe-5: Simple correlations of the pollution evaluator index with the statistical indices calculated for benthos.

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