EFFECT OF ANTHROPOGENIC ACTIVITIES ON THE LIMNOLOGY OF TWO WETLAND ECOSYSTEMS IN AND AROUND RAICHUR,

NORTH, KARNATAKA. INDIA

MALKANNA, RAVINDRAPAUL

Asst. Prof. in Zoology. Prof. in Zoology.L.V.D.College.Raichur. Gulbarga UNiversity.Gulbarga.

584103. KARNATAKA. 585106. KARNATAKemail: malkanna_g@yahoo.co.in : ravindrapaul@gmail.com.

• Wetlands constitute very important habitats which support a vast diversity of organisms.

• They are often described as the ‘kidneys’ of the landscape as they filter sediments and nutrients from the surface waters.

• They support a wide variety of life forms through extensive food webs and inhabitant biodiversity, they are often referred to as ‘biological supermarkets’ (Mitsch &Gosselink, 1993.).

• The present investigation was undertaken to make an assessment of anthropogenic activities and their impact on the physico-chemical and biological parameters by comparison of results (Table-1&2) of the two wetlands – Aam Talab and Samunder Talabwhich are located in Raichur.

• They are situated apart in two different localities wherein the degrees of anthropogenic activities vary quite significantly.

• Anthropogenic activities have varying degrees ofadverse impact on the limnological parameters suchas color, pH, alkalinity, hardness, chloride content,phosphate-phosphorous, nitrate-nitrogen and thebiological parameters viz. primary productivity,secondary productivity and zooplanktonpopulation.

• Results of limnological and biological parameters ofboth the wetlands indicate that Aam talab is greatlyaffected by various anthropogenic activities thanwhen compared with Sumunder talab.

• Raichur is a district head quarter in north Karnataka. It is found between 15o-10’ to 16o-50’ latitude; 75o-80’ to 75o-50’ longitude with an altitude of 347 m above M.S.L. The two wetlands selected for the present study are located within a perimeter of about 10 km in and around Raichur town.

• Materials & Methods: The physicochemical parameters of the two wetlands have been studied to analyze the variations in water quality. The field studies include the site selection, water sampling, frequency and preservation of samples. All the physical and chemical parameters were recorded and their analysis was carried out following standard methodology (APHA, AWWA, WCPF, 2006).

• Some of the major anthropogenic

• 1) Washing, bathing, swimming and other recreational activities;

• 2) Garbage disposal, 3) urbanization and encroachment.

• 4) Discharge from domestic sewage and slaughter house; 5) Extensive inland water fishing.

• 6) cattle grazing and sheep rearing; 7) Irrigational agricultural practices; 8) Brick industries,

• 9) Construction of roads, bund, temples, mosque etc. 10) Pig yard, poultry farm and stable on the bank of wetlands.

• 11) Cremation ground on the bank of wetland. 12) Other direct human activities.

• In the present study annual fluctuation of atmospheric temperature was in the range of 15.4 +/- 10C to 28.5 +/- 0.50C, while, the annual fluctuation of water temperature was from 18.5 +/- 10C to 28.5 +/-0.50C.

• Observations of other parameters v.i.z. TS, TSS & TDS showed their increased presence in Aam talab in comparison with Samundar talabwhich is indicative of the fact that anthropogenic activities cause such a change (Table-1&2 for total solids).

• The concentration of dissolved oxygen in Aam talab during 2005-06 varied between 0.6 mg/L during July to 9.8mg/L during January 2006-07; However, dissolved oxygen levels were quite high in 2006-07 with a low of 8.2mg/L to a high of 12.3mg/L.

• Dissolved oxygen in samundar talab was observed to be uniformly distributed with a low of 5.9 mg/L to a high of 11.0 mg/L during 05-06

• Free carbon dioxide content of Aam talab was found to be nil for most part of the year 2005-06 and similar observations were made during the year 2006-07.

• Free carbon dioxide concentration in samundar talab ranged between 2.2-to- 39.8 mg/L during 2005-06, while ,the same for 2006-07 was found to be nil.

• The chloride concentrations in Aam talab in 2005-06 was found to be from 268.6- 1363.2 mg/L and 440.00 -708.5 mg/L and the same in samundartalab varied between 39.56 – 119.9 mg/L in 2005-06 and 81.15-342.6 mg/L in 2006-07.

• In Aam talab the phosphorus concentration varied between 0.875- 1.765 mg/l during 2005-06 and 1.470- 2.17 mg/L in the year 2006-07. In Samundar talab water phosphorus fluctuated from 1.96- 2.88 mg/L in 2005-06 and 1.32 – 2.44mg/L in 2006-07.

• The concentration of nitrogen in Aam taalab water was found ranging from 430.00 – 710.00 mg/l in 2005-06 and 37.25 – 535.00 mg/L in 2006-07 higher concentration was noticed in February March. The concentration of the same in Samundar talsb varied from 68.47 – 119.9 mg/l in 2005-06; 81.15 – 242.0 mg/L in 2006-07 with a maximum of 242.0 mg /l in January 2006

• In the present study results of biochemical oxygen demand were found fluctuating from 220.0-358.75 mg/L at Aam talab; while it

ranged between 70.0- 270.0 mg/L in Samunder talab.• GPP was in the range of 0.076 – 2.68 mg/l in Aam talab while, it was

in the range of 0.315 – 1.573 mg/L in Samunder talab.

• The observations pertaining to quantitative studies of plankton which is presently denoted as wet weight (Table-1&2) revealed that Aamtalab contained more planktor than Samunder talab.

• zooplankton belonging to eleven genera have been recorded and fourteen species belonging to eleven genera were spotted in Aamtalab. and six species belonging to six genera were found in Samundar talab. These observations reveal that the zooplankton population diversity and number was found to be less in Samundartalab.

• Anthropogenic activities:

The findings of the present research work can be summarized:

• It is clear from these observations that the atmospheric temperature has direct impact over the water temperature. Similar such observations were made by Young(1975), Sehagal(1980), Jayanthi (1994), Mc Comick (1996); Hondz(1980),Stefan et al 9 1993a, 1993b & 1996); Zingade (1981),Hegade et al (1984) on the different water bodies studied by them.

• Comparative study reveals that light penetration was found increasing from Aamtalab, to Samundar talab. This could be attributed due to the decreased indirect effects of the anthropogenic activities such as trampling, fishing, direct discharge of waste water and recreation etc can contribute to the fact that can enhance turbidity.

• The comparative account of total solids, from Aam talab to Samundar talab was being found relative and proportional to the degree and extent of anthropogenic activities, on these wetlands.

• It is the general understanding that alkalinity of water is due to the dissolved in-organic solutes. The leaching of inorganic solutes into water through land drainage is the cause for water pollution.

• It is discernible that quantity of sewage water drainage in to wetland and other factors like human activities including washing of clothes, chlorination of drinking water and also disturbances created by cattle activity could be the major contributors of chlorides to the wetland water

• In the light of the increasing urbanization and human interference in all parts of the wetland environment, level of chloride concentrations in wetland water acts as a fairly important parameters in the assessment of the status of the concerned water body.

• direct release of untreated sewage, open eroding, washing, bathing and cattle activity (indirect human activity) are the main causes for the increased levels of degradable organic matter, which was estimated as BOD and found to be in the higher range in the present investigation.

• The overall observation of plankter wet weight did not vary much from season to season and first annual cycle to the second annual cycle from the Table-1&2 and it is clear that variations in plankter wet weight and almost similar trend was observed in the Aam talab with slight deviation in Samundar talab which could be due to temporary dryness of the tank. However, it is interesting to note that the greater percentage of sewage which also contributes considerable amount of organic matter and silt perhaps be the major cause for the higher values of dry weight of planktons which are the second step, in the food chain of wetland ecosystem.(Hence dry weight is not considered in Table-1&2).

Impacts of urbanization on aquatic resources

• The total impervious surface area (i.e., the urban/suburban land area covered with buildings, concrete, asphalt, and other “hard,” or impervious, surfaces) is a very important indicator or measure of the negative impact of land use changes on aquatic systems.

• There is growing documentation throughout the country that land use practices, and the associated creation of increased impervious surfaces, negatively impact aquatic ecosystems and cause increased frequency and magnitude of flooding and bank erosion.

• Even relatively small changes in wetland regimes can significantly impact wetland ecosystems by increased erosion and degradation of habitat for fish and fish food organisms.

• It is discernable that, among the various kinds of anthropogenic activities, release of untreated domestic and agricultural sewage water could be the major cause for the all time higher values of various chemical, biological factors and also could be the cause for physical characteristics such as water colour, odour, suspended solids etc.

Impacts of irrigational agricultural practices:

• Direct loss of wetlands due to draining and conversion to agricultural land.• Indirect loss of wetlands area due to water withdrawal for irrigation.• Loss of wetland area and function due to loss of water storage.• Loss of seasonal wetlands due to changed hydrologic cycle from water

storage.• Loss of wetland functions due to salinization, sediment deposition, erosion,

eutrophication.• Pollution from use of pesticides and other chemicals; used in these so called

modern irrigational practices• Impact of other anthropogenic activities:• Some of the less significant anthropogenic activities such as brick industries

especially clay brick industries of small scale may add to the water withdrawal and also contribute in leaching of nitrate and phosphates through natural land drainage during rain water impoundments.

• The nutrient loading into the wet land is also attributed to some of the anthropogenic activities such as pig yard, poultry farm, stable and cattle activities in the watershed areas of these wetlands

• It is discernable that city garbage affecting the water quality such as odour, colour, and acts as land fills in the watershed area.

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