Response of a marine sediment microbial community exposed to 2,4-dichlorophenoxyacetic acid

• Published in: Microbial ecology Vol. 35; no. 1; pp. 72 - 82
• Main Authors: Hogan, M.E. (University of California Santa Cruz, Santa Cruz, CA.), Ward, B.B
• Format: Journal Article
• Language: English
• Published: New York, NY Springer-Verlag New York Inc 01.01.1998; Springer
• Subjects: 2,4-D; Acclimatization; Animal, plant and microbial ecology; Applied ecology; AQUATIC COMMUNITIES; Biofilms; Biological and medical sciences; Bottles; COMMUNAUTE AQUATIQUE; COMUNIDADES ACUATICAS; Diffusion coefficient; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Marine; Marine and brackish environment; MARINE AREAS; MICROBIAL ACTIVITIES; MICROORGANISME; MICROORGANISMOS; MICROORGANISMS; Particulate matter; Productivity; REGION MARINE; Sea water; Sedimentary soils; Sediments; Xenobiotics; ZONAS MARINAS; Biodegradation; Microorganism growth; Marine sediments; Ecotoxicology; 2,4-D; Herbicide; Biological productivity; Marine environment; Pollutant; Bacteria; Water pollution; Phytohormone; Microbial community; Population density; Adaptation
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s002489900061

Acclimation of a marine sediment microbial community to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was examined by comparing its ability to metabolize 2,4-D before and after exposure to the herbicide. The experimental treatments (control: 2-week exposure, seawater only; test: 2-week exposure, seawater plus 100 ppm 2,4-D) took place under simulated in situ conditions, in an incubation chamber, which maintained the physical and chemical gradient structure of the sediment community. The surface of the sediment was exposed to recirculating seawater on a tidal cycle. 2,4-D (100 ppm) was added to the seawater so that its availability to the sediment microbes mimicked the natural situation. Before and after treatment, bacterial abundance, productivity, and transformation of 2,4-D were determined. After 2 weeks, bacterial populations were similar in the 2,4-D treatment and the initial sediment sample, but higher in the seawater-only treatment. Bacterial productivity was higher in both 2-week treatments, compared to productivity measured before treatment, but rates were the same in 2,4-D and seawater treatments. In contrast, 2,4-D transformation rates increased 28% in the 2-week 100-ppm 2,4-D treatment, compared to the average of the seawater control and the initial sample. This increased transformation rate indicates that the sediment community acclimated to the selective pressure of 2,4-D treatment by increasing its ability to utilize this compound as a substrate