FAQ Topic

How to deal with fouling (marine growth)?

Bio-fouling is a potential problem but one that can typically be overcome.

In certain environments organisms such as barnacles and algae can start growing on the SediMeter. The photos show what can happen in the perhaps worst possible case, a shallow nutrient-rich tropical sea just off Miami.

Fortunately, even in this extreme case the lowest 10 cm or so remained clean. It is apparent that the leaves and sand grains that got swirled around by the waves prevented the organisms from getting a foothold.

Day 0: At 6 m depth in 27 ºC with no anti-fouling treatment. Off Cape Florida outside Miami. Past beach replenishment projects, and nutrients from land, probably contribute to poor visibility.	Day 24: Algae and barnacles cover everything except the lower part of the sensor.
Day 24: Close-up of the sensor. Enough backscatter detectors are still visible for it to continue measuring the bottom level. No biofouling occurred on the sensor inside, only on the outer holder tube.	2 m depth, same area, day 9: This sensor also escaped biofouling in the lowest section. The photo was taken on a relatively calm day, and still sand grains swirl around the sensor with every wave. It appears this kept it from biofouling.

Bio-fouling is not a problem in all places or at all times. For instance, several months of deployment under the ice in a temperate lake, at 2 m depth, produced no bio-fouling whatsoever. The same for 2 summer weeks at 21 m depth in the southern Baltic Sea. For fouling of benthic fauna to occur, there must be an event of larvae settling. In some waters this only happens once per season, but in tropical waters it happens often. For fouling of algae and slime (which depend on photosynthesis) to occur, there must be sufficient light.

Does your application require a clean sensor for a prolonged time? If fouling is a potential problem, one solution is regular cleaning in connection with routine inspections. If routine cleaning is cost-prohibitive, and you need a significant number of instruments, we have a few solutions that can be operationalized in a reasonable time. Contact us for a discussion.