Rising salinity from road deicing salts threatens the survival and reproduction of freshwater organisms. We conducted two experiments to address how
Ranaviruses are emerging pathogens that have caused mortality events in amphibians worldwide. Despite the negative effects of ranaviruses on amphibian populations, monitoring efforts are still lacking in many areas, including in the Prairie Pothole Region (PPR) of North America. Some PPR wetlands in Montana and North Dakota (USA) have been contaminated by energy-related saline wastewaters, and increased salinity has been linked to greater severity of ranavirus infections. In 2017, we tested tissues from larvae collected at 7 wetlands that ranged in salinity from 26 to 4103 mg Cl l-1. In 2019, we used environmental DNA (eDNA) to test for ranaviruses in 30 wetlands that ranged in salinity from 26 to 11754 mg Cl l-1. A previous study (2013-2014) found that ranavirus-infected amphibians were common across North Dakota, including in some wetlands near our study area. Overall, only 1 larva tested positive for ranavirus infection, and we did not detect ranavirus in any eDNA samples. There are several potential reasons why we found so little evidence of ranaviruses, including low larval sample sizes, mismatch between sampling and disease occurrence, larger pore size of our eDNA filters, temporal variation in outbreaks, low host abundance, or low occurrence or prevalence of ranaviruses in the wetlands we sampled. We suggest future monitoring efforts be conducted to better understand the occurrence and prevalence of ranaviruses within the PPR.
more » « less- Award ID(s):
- 1754474
- PAR ID:
- 10512346
- Publisher / Repository:
- Inter-Research
- Date Published:
- Journal Name:
- Diseases of Aquatic Organisms
- Volume:
- 147
- ISSN:
- 0177-5103
- Page Range / eLocation ID:
- 149 to 154
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Daphnia pulex survival and reproduction were affected by road salt concentration (control, 120, 640 and 1200 mg Cl−/L) crossed with three concentrations of water hardness (20, 97, 185 mg CaCO3/L).D. pulex survival was poor in our hard water treatment in both experiments (185 mg CaCO3/L), potentially indicating a low tolerance to hard water for the strain used in our experiments. With the remaining two hardness treatments (20 and 97 mg CaCO3/L), we found no evidence of an interactive effect between salt concentration and water hardness onD. pulex survival. In our population-level experiment,D. pulex survival was reduced by > 60% at 120 mg Cl−/L compared to the control. In the individual experiment, survival was similar between the control and 120 mg Cl−/L, but ≤ 40% of individuals survived in 640 and 1200 mg Cl−/L. For the surviving individuals across all treatments, the number of offspring produced per individual declined with increasing Cl−concentration and in hard water. Our results indicate that current Cl−thresholds may not protect some zooplankton and reduced food availability per capita may enhance the negative impacts of road salt. -
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3354/dao03640
