31820115
Description
Flashcards by Sree Lakshmi, updated more than 1 year ago
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Created by Sree Lakshmi
about 3 years ago
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| Question | Answer |
| ABIOTIC FACTORS IN WATER | -PHYSICAL FACTORS -CHEMICAL FACTORS |
| PHYSICAL FACTORS | -DEPTH -TEMPERATURE -TURBIDITY -WAVE -LIGHT -SALINITY |
| DEPTH | -determines temp, circulation pattern of water, penetration of sunlight, photosynthetic activity -shallower than 1m-overheated in tropical summers -with 2m depth is compatible -determining the farm's fish producing capacity. |
| TEMPERATURE | -depends on climate, sunlight, depth -metabolic, physiological activities and life processes of aq. org. is influenced by water temp. -Eurythermal organisms: wide range of temperature tolerance e.g: Indian major carp: b/w 18.3-37.8 C -the oxygen content decreases as temp increases -the prior knowledge of max and min temp of water body -Tilapia can't-temp below 8.3oC -air breathing fishes -Anabas testudineus, Channa punctatus, Puctius ticto-temp b/w 39-41oC -deep lake in temperate regions has a gradual decrease in temp from surface to bottom-thermal stratification. -upper warmer zone is epilimnion- lower cooler zone is hypolimnion -in b/w intermediate zone- thermocline/ metalimnion, -upper and lower deffers chemically and biologically -a pond is said to be thermally stratified if the upper and lower temp is different -epilimnion-photosynthetic activity -hypolimnioin-acidic/neuttal zone, a biological desert-anaerobic org -thermocline-fish mortality-low dis. O2 |
| TURBIDITY | -suspended particles-silt,clay,plankton -restrict sunlight-absorb nutrients P, K, N -Indian major carps-high turbidity from 2000 and more -very high turbidity-harmful for fish &fish food org. |
| WAVE ACTION, EROSION AND SILTING | -caused by unprotected sides of fish and ponds -unfavourable to fish life -prevents water bed-destroy spawning bed-erosion-inc. turbidity -light penetration dec.-fish food prod. dec. -wave breakers prevents wave action-inc. fish prod. |
| LIGHT | -infl. primary prod. -light penetration-location of pond-shading-depth-turbidity -shading in culturing-controls algal blooms and submerged weeds |
| SALINITY | -amount of dissolved salt in water -expressed in ppt -fresh water-5ppt and below -sea water-30-35ppt -brackish water-5-35ppt -fish-wide range tolerance-euryhaline -narrow range tolerance-stenohaline |
| CHEMICAL FACTORS | -pH -ALKAILINITY -DISSOLVED OXYGEN -CARBON DIOXIDE -TOTAL HARDNESS -DISSOLVED NITROGEN &COMPOUNDS -PHOSPHOROUS -CALCIUM & MAGNESIUM -SODIUM &POTTASIUM -TRACE ELEMENTS -POLLUTANTS |
| pH | -neutral/slight alkaline-not acidic -not below 4.5 and above9 -acidic can cause: less growth rate-less appetite; high microbial infection; less CO2-less photo activity; removes lime from h2o-reduces growth of skeleton & scales |
| ALKAILINITY | -caused by CO3, HCO3, hydroxides of Ca, Mg, Na, K, Fe. -these + diss. CO2 = equilibrium system-imp. in ecology of envi. -calcareous water along with alkailinities more than 50 ppm-more productive |
| DISSOLVES OXYGEN | -receives O2 through: interaction with atmos. air, photosynthesis -vol. of O2 dissolved depends on: temp, partial pressure of O2, conc. of dissolved salts -diurnal fluctuation in diss. O2-min in morning-gradual inc. at noon-declines at night -below 3ppm diss. O2, asphyxia-maintains a fav. condition in varied fish fauna,5ppm diss. O2 required. |
| CARBON DIOXIDE | -CO2 receives from: atmosphere; respiration of plants & animals; inflowing ground water; decomposition of organic matter; water with Ca & Mg -CO2level below 10mg/l is tolerance -level of diss. CO2 in water depends on: respiration & photo; decomposition; respi. of fishes. -CO2 level can be high in system with large no. of fishes and slow water turnover -effect of high level of CO2-hypercapnia-dropping blood pH level-acidosis in fish body-reducing O2 carrying capacity of haemoglobin. |
| TOTAL HARDNESS | -total diss. Ca & Mg in water-expressed in its CaCO3 equivalent -hardness less than 11 ppm-requires liming- high production of fishes -hardness less than 5 ppm-slow growth, distress and eventual death of fish. |
| DISSOLVED NITROGEN AND ITS COMPOUNDS | -either derives from outside source or water body itself -nitroge. compounds produce from animal and plant tissue -most blue green algae-anabena cylindrica, nostoc muscorum secretes nitrogeneous comp. along with polypeptides, amides. amino acids. -the nitron cycle in water body- fixation of atm. nitrogen; ammonification of complex nitrogenous comp.; nitrification of ammonia; denitrification of nitrates |
| PHOSPHOROUS | -maintains pond fertility -occurs as 3 components-inorganic or solid phosphate phosphorous; soluble organic phosphorous; soluble particulate phosphorous occuring in detrit8us & planktons -source-rocks; leaching of soil during catchment of area by rain; liberates from dead org. by bacterial action -excess phosphorous in main water-sign of organic pollution |
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