Mr Evan Forbes1
1Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University, Townsville, Australia
Biography:
Evan is a Masters student in James Cook University's Master of Marine Biology program. Currently doing volunteer research with the Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER) into techniques for passsive sampling of environmental DNA. This is Evans debut into sicentific publications and presenting academic findings.
Abstract:
Environmental DNA surveys have become a crucial tool for ecologist, biosecurity monitoring, and citizen scientist due to its lower costs and the ease of data collection. In aquatic environments most studies are designed around either collecting and preserving water samples or active water filtration. Both of these methods work well but have shortcomings; filtering water in the field is often time consuming, while collecting water samples requires the transport and storage of large volumes of liquid. Here we propose leveraging the adsorptive properties of a layered double hydroxide (LDH) as a method of passively sampling eDNA that is compact, environmentally friendly, and easy to use. By treating aluminum foil with a solution of 0.1 M magnesium chloride and sodium bicarbonate we generated a Mg-Al LDH on the foil surface. The method was first trialled in an aquarium setting using invasive tilapia as a model organism, whereby 18 replicate LDH foils were exposed to aquarium water for 30-minute, 60-minute and 24-hour intervals, with 3 replicates and 1 control per treatment and 2 treatments per time interval. The DNA was extracted following either a standard commercially available DNA extraction kit or a modified procedure where samples were treated with a 1 M phosphate solution followed by DNA precipitation prior to extraction via the commercial kit. Tilapia eDNA was detected from all replicates of 5×3 cm LDH foil passive samplers with a 30-minute exposure time, with marginal gains in eDNA concentration up to 24-hour exposure. Samples treated with a phosphate solution were also demonstrated to yield significantly higher concentrations of eDNA, 8-16 times that of the non treated samples. Experiments testing a phosphate-sds preservative buffer for eDNA sample storage at high temperatures are currently underway.