Importance of Freeze鈥揟haw Events in Low Temperature Ecotoxicology of Cold Tolerant Enchytraeids

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• 作者：Ana L. Patr铆cio Silva ; Kirsten Enggrob ; Stine Slotsbo ; M贸nica J. B. Amorim ; Martin Holmstrup
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：August 19, 2014
• 年：2014
• 卷：48
• 期：16
• 页码：9790-9796
• 全文大小：301K
• ISSN：1520-5851

文摘

Due to global warming it is predicted that freeze鈥搕haw cycles will increase in Arctic and cold temperate regions. The effects of this variation becomes of particular ecological importance to freeze-tolerant species when it is combined with chemical pollutants. We compared the effect of control temperature (2 掳C), daily freeze鈥搕haw cycles (2 to 鈭? 掳C) and constant freezing (鈭? 掳C) temperatures on the cold-tolerance of oligochaete worms (Enchytraeus albidus) and tested how survival was influenced by pre-exposure to 4-nonylphenol (4-NP), a common nonionic detergent found in sewage sludge amended soils. Results showed that combined effect of 4-NP and daily freeze鈥搕haw cycles can cause higher mortality to worms as compared with sustained freezing or control temperature. Exposure to 4-NP caused a substantial depletion of glycogen reserves which is catabolized during freezing to produce cryoprotective concentrations of free glucose. Further, exposure to freeze鈥搕haw cycles resulted in higher concentrations of 4-NP in worm tissues as compared to constant freezing or control temperature (2 掳C). Thus, worms exposed to combined effect of freeze鈥搕haw cycles and 4-NP suffer higher consequences, with the toxic effect of the chemical potentiating the deleterious effects of freezing and thawing.