Limnology of rock pools in the river Chenab at Dhoomi, Akhnoor, in Jammu region of the Union Territory of Jammu and Kashmir

Abstract

Small and temporary freshwater rock pools, compared to lakes, ponds and rivers, have received a very little scientific attention in India. For the present limnological study, six rock pools in the river Chenab at Dhoomi, Akhnoor, were analysed seven times for water quality and fauna during 17-01-2011 to 26-01-2011 and have been described. Among various water parameters depth (6-11 cm), transparency (6-11 cm) and turbidity (1.4-6.88 NTU) recorded a decrease after high record on first observation. Salinity remained constant (0.1 ppt) on all the seven observations. Dissolved oxygen (DO) observed maximum (12.81 mg/l) record on 19-01-2011 and minimum (9.99 mg/l) on 26-01-2011. Chloride (Cl?) was minimum (2.73 mg/l) on 17-01-2011 and 18-01-2011 and maximum (6.81 mg/l) on 24-01-2011. Conductivity (75.50 – 178.8 µS cm?¹), total dissolved solids (TDS) (40.13 – 85.5 mg/l), Biological oxygen demand (BOD) (2.5 – 6.63 mg/l), pH (8.26 – 9.12), carbonate ( CO3-2) (2.31 – 22.84 mg/l), bicarbonate (HCO3-) (29.83 – 71.29 mg/l), calcium (Ca+2) (9.45 – 29.50 mg/l), magnesium (Mg+2) (2.24 – 5.38 mg/l), total hardness (TH) (35.34 – 95.80 mg/l) and sodium (Na+) (0.44 – 1.05 mg/l) showed highest record on last observation. Potassium (K+) (0.60 – 1.70 mg/l) was minimum on 18-01-2011 and maximum on 24-01-2011. Nitrate (NO3?) (0.084-0.373 mg/l), phosphate (PO4³? ) (0.043 – 0.140 mg/l), silicate (SiO4-4) (1.28 – 3.95 mg/l) and sulphate (SO4-2) (4.89 – 7.84 mg/l) observed an irregular pulse. Fauna in these rock pools was represented by zooplankton (passive dispersers) belonging to Protozoa (27 species), Rotifera (3 species), gemmules of Porifera (2 species) and Turbellaria (1 species) only. Zooplanktonic maximum qualitative record was observed on 6th observation and quantitative on 7th observation. In the absence of any earlier study on freshwater rock pools in the Himalayan rivers, present work shall be of great help for future workers.