Pore Water Extraction Method
Pore water
in situ
Collection
A method for in situ collection of pore water in sandy
sediments
Coastal environments accounts for 50% of earth’s total carbon transfer to marine
sediment. The top part of the sediment column just below the sediment – water
interface experiences high chemical and biological reactions which influences the
carbon and other associated element cycle in the ocean. These reactions rapidly
changes the chemical composition of the sediment and pore water. Due to relatively
larger grain size of the sediment in some coastal environments, sediment mixes
quickly making collection of pore water extremely difficult. Here, we present a simple
method utilizing rhizon samplers to collect in situ pore water from coastal
environments from the Gulf of Aqaba, Red Sea. We conducted a tracer experiment
to assess the overlying water contamination and demonstrate the threshold amount
of sample to be collected. We present two case studies where we measured: (1) the
iron concentration of pore water and observed peaks wherever the sediment was red
in appearance and (2) the change in alkalinity and concentration of phosphate,
ammonium and nitrate with time for seagrass meadows. Each study demonstrates
the expected trend in geochemical signature changes in pore water and hence
independently validate the rhizon sampler method for collecting pore water from
marine sediments. Therefore, we suggest that at a nascent stage, the rhizon sampler
method demonstrates high potential for easy collection of pore water for various
geochemical studies.)
Saurav Dutta , Raoul Saar , Zach Lavie , Gal Vered, Gilad Antler.