Diver-operated manual suction pump sampler: a reliable method for sampling benthos on rock substrates

Although numerous methods have been developed for SCUBA diver-operated sampling, few are suitable for sampling complex physical substrates. Sites such as groundwater springs sometimes have narrow sections along with uneven vertical and horizontal rock substrates at various depths. Here we developed a SCUBA diver-operated suction pump sampling system, designed for the sampling of benthic material on morphologically complex substrates. The sampler was designed to be simple to use in an already gear-heavy operation. The device is attached to the diver, making it a suitable tool for work on vertical substrates, and can be operated by 1 person. We compared the macrozoobenthic sampling yield and usability of the suction pump sampler to a Surber sampler that was modified for use while diving. Samples taken with the suction pump sampler had an overall greater macrozoobenthic density and species richness than samples taken with the modified Surber sampler. Sampling was more efficient with the suction pump sampler, as sampling containers were easily replaced underwater, whereas the modified Surber needed to be transported to the surface and its sample fixed before the next sample could be taken. Various modifications of the suction pump sampler are possible, depending on the objective of the sampling process, and it can be constructed with inexpensive and readily available materials. The suction pump sampler presented here further allows researchers in the field of marine and freshwater ecology to accurately sample the benthic habitat, including habitats where physical complexity may previously have prevented sampling.