Estuarine fish in the northern Gulf of Mexico are exposed annually to hypoxic conditions. In addition to hypoxia, fish located throughout the northern Gulf of Mexico were potentially exposed to oil released during the Deepwater Horizon incident. Therefore, the interaction between oil exposure and hypoxia is worth investigating. To examine this interaction, the authors exposed adult and larval sheepshead minnow (Cyprinodon variegatus) to crude or dispersed oil under both normoxic and hypoxic conditions. The authors examined total egg production, egg hatching success, and larval survival post hatch. The authors' results indicate that co-exposure to crude or dispersed oil and hypoxia resulted in a significant decrease in egg production, as well as a significant decrease in both egg hatch success and larval survival post hatch. The significant impact on reproductive success following crude or dispersed oil and hypoxia exposure indicates the importance of including environmental parameters such as hypoxia when evaluating the impact of an oil spill.
Extracting and identifying genetic material from environmental media (i.e. water and soil) presents a unique opportunity for researchers to assess biotic diversity and ecosystem health with increased speed and decreased cost as compared to traditional methods (e.g. trapping). The heterogeneity of soil mineralogy, spatial and temporal variations however present unique challenges to sampling and interpreting results. Specifically, fate/transport of genetic material in the terrestrial environment represents a substantial data gap. Here we investigate to what degree, benthic fauna transport genetic material through soil. Using the red worm (Eisenia fetida), we investigate how natural movement through artificial soil affect the transport of genetic material. All experiments were run in Frabill® Habitat® II worm systems with approximately 5 cm depth of artificial soil. We selected an “exotic” source of DNA not expected to be present in soil, zebrafish (Danio rerio) tissue. Experiment groups contained homogenized zebrafish tissue placed in a defined location combined with a varying number of worms (10, 30 or 50 worms per experimental group). Experimental groups comprised two controls and three treatment groups (representing different worm biomass) in triplicate. A total of 210 soil samples were randomly collected over the course of 15 days to investigate the degree of genetic transfer, and the rate of detection. Positive detections were identified in 14% - 38% of samples across treatment groups, with an overall detection rate of 25%. These findings highlight two important issues when utilizing environmental DNA for biologic assessments. First, benthic fauna are capable of redistributing genetic material through a soil matrix. Second, despite a defined sample container and abundance of worm biomass, as many as 86% of the samples were negative. This has substantial implications for researchers and managers who wish to interpret environmental DNA results from terrestrial systems. Studies such as these will aid in future study protocol design and sample collection methodology.
The Organisation for Economic Co‐operation and Development (OECD) test guideline 236 (fish embryo acute toxicity test; 2013) relies on 4 endpoints to describe exposure‐related effects (coagulation, lack of somite formation, tail‐bud detachment from the yolk sac, and the presence of a heartbeat). Danio rerio (zebrafish) embryos were used to investigate these endpoints along with a number of additional sublethal effects (cardiac dysfunction, pericardial edema, yolk sac edema, tail curvature, hatch success, pericardial edema area, craniofacial malformation, swim bladder development, fin development, and heart rate) following 5‐d exposures to 7 petroleum substances. The substances investigated included 2 crude oils, 3 gas oils, a diluted bitumen, and a petrochemical containing a mixture of branched alcohols. Biomimetic extraction–solid‐phase microextraction (BE–SPME) was used to quantify freely dissolved concentrations of test substances as the exposure metric. The results indicated that the most prevalent effects observed were pericardial and yolk sac edema, tail curvature, and lack of embryo viability. A BE–SPME threshold was determined to characterize sublethal morphological alterations that preceded embryo mortality. Our results aid in the understanding of aquatic hazards of petroleum substances to developing zebrafish beyond traditional OECD test guideline 236 endpoints and show the applicability of BE–SPME as a simple analytical tool that can be used to predict sublethal embryo toxicity. Environ Toxicol Chem 2019;38:1302–1312. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.