Effects of glyphosate herbicide on the gastrointestinal microflora of Hawaiian green turtles (Chelonia mydas) Linnaeus. (February 2018)

• Record Type: Journal Article
• Authors: Kittle, Ronald P.; McDermid, Karla J.; Muehlstein, Lisa; Balazs, George H.
• Is Part Of: Marine pollution bulletin. Volume 127(2018)
• Page Start: 170
• Page End: 174
• Publication Date: 2018-02
• Subjects: Bacteria -- Digestion -- Glyphosate toxicity -- Green turtle -- Hawaii -- Microbial communities; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2017.11.030
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: In Hawaii, glyphosate-based herbicides frequently sprayed near shorelines may be affecting non-target marine species. Glyphosate inhibits aromatic amino acid biosynthesis (shikimate pathway), and is toxic to beneficial gut bacteria in cattle and chickens. Effects of glyphosate on gut bacteria in marine herbivorous turtles were assessed in vitro . When cultures of mixed bacterial communities from gastrointestinal tracts of freshly euthanized green turtles ( Chelonia mydas ), were exposed for 24 h to six glyphosate concentrations (plus deionized water control), bacterial density was significantly lower at glyphosate concentrations ≥ 2.2 × 10 − 4 g L − 1 (absorbance measured at 600 nm wavelength). Using a modified Kirby-Bauer disk diffusion assay, the growth of four bacterial isolates ( Pantoea, Proteus, Shigella, and Staphylococcus ) was significantly inhibited by glyphosate concentrations ≥ 1.76 × 10 − 3 g L − 1 . Reduced growth or lower survival of gut bacteria in green turtles exposed to glyphosate could have adverse effects on turtle digestion and overall health. Highlights: Bacteria isolated from green turtle GI tract were exposed to glyphosate in vitro . Bacterial density was significantly lower in glyphosate conc. ≥ 2.2 × 10 − 4 g L − 1 . Growth of 4 taxa was significantly inhibited by glyphosate conc. ≥ 1.76 × 10 − 3 g L − 1 . Growth of GI tract bacteria from marine green turtles is affected by glyphosate. Lower survival of gut bacteria could have adverse effects on green turtle digestion.