Physical fracttonatton pre‐treatment of the organic matter dissolved in marine pore waters

Abstract

The organic matter dissolved in pore waters is complex and difficult to study directly. The coupling of tangential ultrafiltration (cut‐off 1000) and gel permeation chromatography (Sephadex G15) with sea water as eluent proved more efficient than existing procedures to fractionate the natural dissolved organic matter (DOM). An effective fractionation was achieved, and fractions with similar retention times were observed in very different samples. Our experimental‐conditions simplified the characterisation of this dissolved organic matter, with no extraction, chemical treatment, or preconcentration step on a resin. They also facilitate investigations which were difficult to carry out directly on pore waters. To illustrate this, the complexing ability versus copper of the obtained fractions was shown to correlate significantly with the total amino‐acids concentration (r = 0.64, p = 0.01).