Experiment 1: DNA Degradation
An DNA degradation experiment was conducted using C. sivickisi to
determine how quickly eDNA may degrade once the jellyfish is removed.
Decay to < 1% of the original eDNA concentration has been
found in some studies to take anywhere from 48 hr to 10 days (Thomsenet al. 2012; Pilliod et al. 2014); however, there have
been no such determinations for cubozoans. In this trial, C.
sivickisi medusae were collected at night off the coast of Magnetic
Island, North Queensland (24/09/2019). Once collected, a single adult
jellyfish (inter-pedalia distance 2-3 cm; n = 16) was placed in a 10 L
bucket (n = 16) filled with 7 L of artificial saltwater. After 12 h the
medusa was removed. Each bucket (n = 4) was sampled once so that all
samples were independent with the full 7 L of water being filtered
through 5 um nylon filters. The filtering of water (n = 4 buckets per
time) was undertaken on day 0, 3, 6 and 9 post the removal of jellyfish
to determine the concentration of eDNA remaining in the water column.
Filter papers were placed in sterilised 2 mL tubes containing 1 mL of
Longmire solution (Renshaw et al. 2015; Williams et al.2016) and stored at 4 oC for future extraction and
analysis.