Differences in bathymetric distribution and diel (day-night) feeding activity were analyzed with a Kruskal-Wallis test [ 53].
Previous studies of the mat have revealed diel (day-night) metabolic variation in various community members, driving shifts in the concentration and fate of dissolved metabolites [ 5, 6, 10- 12].
We did two separate experiments in two south-eastern Australian estuaries to test the hypotheses that samples of fish and invertebrates taken using a demersal otter trawl would be affected by: (i) vertical net height (standard 0.8 m vs. high-rise 1.2 m) and tow duration (5 vs. 10 vs. 20 min); and (ii) diel period (day vs. night) and tow duration.
Separate models were constructed to represent two distinct phases of a diel cycle, day and night.
Real-time PCR showed that mRNAs of these circadian clock genes exhibited extremely weak diel oscillations at day 9 in the head of R. pedestris, and their expression levels under long- and short-day conditions were nearly identical.
Next, we observed that the female was exclusively (or almost exclusively) at the nest location for a complete diel cycle on the first day of incubation.
In tree swallows, the number of visits to a nest is an accurate measure of food delivered to nestlings [ 43]. Rose [ 44] found that the cumulative number of tree swallow parental feeding visits increased linearly over the day, indicating that diel variation in visit behavior is unlikely to affect our estimates of feeding rates.
Proportion of encounters relative to the (a) diel cycle (yellow: encounters during the day; dark blue: encounters during the night), (b) tidal cycle and (c) seasonal cycle at the three sampling sites for the whole period studied (2010 2016).
Diel measurements were conducted throughout the day (it took about 2 h to complete one round of gas sampling), starting at predawn and ending at nightfall, roughly every 4 to 6 h.
These differences in sunrise and sunset were not considered substantial, so full hours of the day were pooled in the diel analysis.
To maintain sampling consistency with respect to the diel cycle, cells were sampled at 14 00 every day.
