Freshwater ecosystems are being exposed to increasing salinisation, often because of pollution from road deicing salts, which is becoming more widely acknowledged. To address this issue, municipalities are turning towards the sodium salt alternatives of CaCl2and MgCl2, which are marketed as being safer for the environment. However, research into the actual safety of these salts on aquatic plants is lacking. We investigated the effects of the most common road salt (NaCl) and two alternatives (MgCl2and CaCl2) on the productivity of a common freshwater plant (i.e., We discovered that NaCl and CaCl2altered these measures of plant metabolism, but MgCl2had no effects. We also observed instances of acclimation (i.e. salt effects after 1 week that disappeared after 3 weeks) and lag effects (i.e. no salt effect after 1 week, but salt effects after 3 weeks). These impacts are likely to be the results of plant responses to salt at the cell and molecular levels, including short‐ and long‐term changes in photosynthetic pigments. Therefore, the plant responses were salt‐specific, with instances of plant acclimation and lag effects. This appears to be the first study of net primary productivity, respiration, and gross primary productivity in freshwater plants across a range of different salts, and it highlights how freshwater salinisation can have substantial effects on plant productivity. These effects will probably have an impact on the growth of macrophytes, which play key ecological roles in aquatic ecosystems.
Salt pollution is a threat to freshwater ecosystems. Anthropogenic salt inputs increase lake and stream salinity, and consequently change aquatic ecosystem structure and function. Elevated salt concentrations impact species directly not only through osmoregulatory stress, but also through community‐level feedbacks that change the flow of energy and materials through food webs. Here, we discuss the implications of road salt pollution on freshwater rivers and lakes and how “one size fits all” ecotoxicity thresholds may not adequately protect aquatic organisms.
This article is categorized under: Science of Water > Water Quality Water and Life > Nature of Freshwater Ecosystems Water and Life > Stresses and Pressures on Ecosystems
- NSF-PAR ID:
- 10386452
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- WIREs Water
- Volume:
- 10
- Issue:
- 2
- ISSN:
- 2049-1948
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Practitioner points Pollution from the increasing use of roadway deicers may have detrimental effects on the environment.
Of particular concern are the acute and cumulative risks that chloride salts pose to aquatic species.
Chloride salts are water‐soluble, very difficult to remove, highly mobile, and non‐degradable.
Deicers cause water stratification, change the chemicophysical properties of water, and affect aquatic species and human health.
Current guidelines may not be appropriate for environmental protection and need to be revised.
