Environmental Assessment of Tropical Lentic Ecosystem with Special Reference to Surface Water Quality and Phytoplankton Diversity

For the present study, two tropical lentic ecosystems (ponds) were selected (January to April, 2014) to draw out the relationship between surface water quality and phytoplankton diversity in Central Gujarat, India. The status of water pollution was determined as per CPCB (Central Pollution Control Pollution Board) and GPCB (Gujarat Pollution Control Board) standards. To determine the degree of pollution, following surface water quality parameters were analyzed: Temperature (T), pH, Dissolved Oxygen (DO), Total Solids (TS), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Free CO2, Phenolphthalein Alkalinity (PA), Total Alkalinity (TA), Carbonates (CB), Bicarbonates (BC), Total Hardness (TH), Calcium (Ca), Magnesium (Mg), Chloride (Cl), Salinity (SL), Sulphate (SO4), Phosphate (PO4), Nitrate (NO3), Chromium (Cr), and Iron (Fe). Based on the findings, the studied ponds were categorized as Polluted (PP) & Non-Polluted (NP). Almost all the surface water quality parameters were found within the prescribed limits in NP, whereas most of them were observed beyond the permissible limits in PP. In PP, Correlation Coefficient Matrix (r) revealed the strong positive correlation between PA and TA with CB, TSS and TS with Mg, Mg with Cl, Cl with SL, pH, CB, Ca and SO4 with PO4, TS, TDS, BC, SL and PO4 with NO3, T and DO with Cr, and NO3 with Fe. While in NP, strong positive association was observed in following parameters (pH with PA, PA and TA with CB, TSS and TS with Mg, Mg with Cl, Cl with SL, CB, Ca and SO4 with PO4, TS, TDS, BC, SL and PO4 with NO3, T and DO with Cr, and NO3 with Fe). In case of phytoplankton, more number of families (8) was documented in PP with 11 species (4: Abundant, 7: Common), while in NP only four (4) families were reported with 10 species (6: Abundant, 4: Common). This may be due to blooming of pollution indicator species of phytoplankton exclusively represented by families such as Euglenophyceae (EG), Nostocaceae (NS), Zygnematophyceae (ZG), and Ulvophyceae (UL) in waters of PP. On the other hand, members of families such as Chlorophyceae (CP), Bacillariophyceae (BP), Cyanophyceae (CP), and Florideophyceae (FL) were occurred in both PP and NP. In PP, Correlation Coefficient Matrix (r) revealed the strong positive correlation between CP with pH, CP with PO4, Fl with Cl, ZG with PA and CB, and UL with NO3, whereas, BP, EP and NS exhibited no any correlation with none of the water quality parameters. On the other hand, in case of NP CP showed strong positive correlation with SL, CP with pH, and FL with Cl. Contrastingly, here also BP did not exhibit any correlation with none of the water quality parameters. As a part of conservation and management strategies, central water treatment plant should be installed in PP to eliminate the pollution indicator species of phytoplankton to revive the affluent status of water body for enduring sustainability of a tropical lentic ecosystem of Central Gujarat, India