In this unique study in Australia scientists have shown that Glyphosate (Roundup) primarily in GM agriculture, is particularly resistant to biodegradation in sea water, and could therefore be a major contributor to the decline of marine coral reef systems such as the Great Barrier Reef.
Glyphosate persistence in seawater
Philip Mercurio, Florita Flores, Jochen F. Mueller, Steve Carter, Andrew P. Negri
Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard “simulation” flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25 °C in low-light was 47 days, extending to 267 days in the dark at 25 °C and 315 days in the dark at 31 °C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.