Field testing of an AML oceanographic cabled ultraviolet anti-biofouling system in an estuarine setting

An AML Oceanographic cabled ultraviolet (CUV) light was tested for effectiveness at preventing biofouling in an estuarine setting. The CUV was deployed twice at the US Geological Survey Pearl River site 02492620 at Stennis Space Center, Mississippi. One six week field deployment was during winter conditions (November 12th 2015 to January 5th 2016) and the other during summer conditions (June 8th to July 25th 2016). During each deployment two EXO multi-parameter sondes with identical sensors were deployed side by side. Sondes deployed were an EXO2 with the CUV attached and an EXO1 control unit without a CUV. A Third EXO sonde that is maintained by the USGS Hydrologic Instrumentation Facility at the Pearl River site was used as the reference. Photographs taken weekly showed the sonde protected by the CUV was noticeably cleaner than the control unit. Although the configuration of the attached sensors resulted in shadowing and growth in the shaded areas, those areas exposed to the direct UV showed little biofouling. During summer conditions, data from the sonde with the CUV showed better agreement with the reference EXO sonde for pH, turbidity, and specific conductance once biofouling had begun to accumulate on the control sonde. During winter conditions, data from the sonde with the CUV showed better agreement with the reference sonde for turbidity than the sonde without the CUV.

I. Introduction

Researchers in both fresh and marine environments continue to struggle with biofouling prevention. Biofouling makes it difficult to ensure high quality data collection throughout a deployment. Biofouling increases the number of visits required to maintain continuous water quality monitoring sites and limits the length of accurate data collection in autonomous deployments. Two of the more commonly used biofouling prevention techniques are the use of environmentally hazardous chemicals or reactive coatings that are effective for a limited time [1]. Mechanical wipers can be unreliable and ineffective on complex geometries.