A free and user-friendly software protocol for the quantification of microfauna swimming behavior.

Characterizing swimming behavior can provide a holistic assessment of the health, physiology and ecology of microfaunal species when done in conjunction with measuring other biological parameters. However, tracking and quantifying microfauna swimming behavior using existing automated tools is often difficult due to the animals' small size or transparency, or because of the high cost, expertise, or labor needed for the analysis. To address these issues, we created a cost-effective, user-friendly protocol for behavior analysis that employs the free software packages HitFilm and ToxTrac along with the R package 'trajr' and used the method to quantify the behavior of rotifers. This protocol can be used for other microfaunal species for which investigators may face similar issues in obtaining measurements of swimming behavior.

Potential impacts of environmental bacteria on the microbiota of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle eggs and their hatching success.

Sea turtle hatching success can be affected by many variables, including pathogenic microbes, but it is unclear which microbes are most impactful and how they are transmitted into the eggs. This study characterized and compared the bacterial communities from the (i) cloaca of nesting sea turtles (ii) sand within and surrounding the nests; and (iii) hatched and unhatched eggshells from loggerhead (Caretta caretta) and green (Chelonia mydas) turtles. High throughput sequencing of bacterial 16S ribosomal RNA gene V4 region amplicons was performed on samples collected from 27 total nests in Fort Lauderdale and Hillsboro beaches in southeast Florida, United States. Significant differences were identified between hatched and unhatched egg microbiota with the differences caused predominately by Pseudomonas spp., found in higher abundances in unhatched eggs (19.29% relative abundance) than hatched eggs (1.10% relative abundance). Microbiota similarities indicate that the nest sand environment, particularly nest distance from dunes, played a larger role than the nesting mother's cloaca in influencing hatched and unhatched egg microbiota. Pathogenic bacteria potentially derive from mixed-mode transmission or additional sources not included in this study as suggested by the high proportion (24%-48%) of unhatched egg microbiota derived from unknown sources. Nonetheless, the results suggest Pseudomonas as a candidate pathogen or opportunistic colonizer associated with sea turtle egg-hatching failure.