An improved device with an affinity membrane to collect depth specific contamination free water for environmental assessment.

The prime requirement for marine water studies is a competent sampling device that can collect water samples perfectly without any contamination to avoid false analysis. The present study demonstrates the design and operation of a cost-effective novel water sampler, which collects contamination-free water from any desired depths of seawater. The sampler is also fitted with polyvinylidene fluoride (PVDF) membranes with improved property for concentration of diversified bacteria. To test the efficiency of the designed sampler under field conditions, the differential depth water sampler (DDWS) was deployed at two coastal sampling stations to collect water samples from various depths. The collected water across the water column was then analyzed for bacterial diversity (culturable and functional bacterial diversity), various environmental parameters (pH, TDS, turbidity, density, salinity, inorganic phosphate, BOD, DO, COD, and total nitrogen), zoo, and phytoplankton to confirm the efficacy of the DDWS. The sampler-appended membrane could concentrate diversified bacteria from different seawater depths. Further, the bacterial diversity study, environmental parameters, and zoo and phytoplankton study showed a marked variance across different depths. The results thus obtained supported that the newly designed DDWS could successfully sample contamination-free water from various depths in seawater. The invented water sampler is easy to construct and operate, and the collected contamination-free water volume (3.5 L) suffices the requirement for the analyses of major water parameters entailed for different marine environmental studies.