Tracing the source and fate of biopolymers in seawater: application of an immunological technique

To investigate the complex degradation dynamics taking place in the water column, it is necessary to develop probes of high sensitivity and specificity that can identify the source and trace the fate of molecules in the dissolved and particulate pools using unconcentrated seawater. Here we present the application of an immunological probe to perform highly sensitive seawater analysis. We used exopolymers produced by the colonial bloom-forming alga, Phaeocystis (Prymnesiophyte), as a model to test the sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) in unconcentrated seawater samples. We tested the ELISA with seawater from the Ross Sea, Gulf of Alaska and the North Water Polynya. We show that ELISA can readily be applied to quantify the concentration of Phaeocystis exopolymers and study their spatial and temporal distribution. With appropriate immunological probes, the ELISA can provide a powerful and highly specific method with nanomolar sensitivity to identify, quantify and trace the dynamics of complex moieties found in seawater.