Humic substances influence sodium metabolism in the freshwater crustacean Daphnia magna

Chris N. Glover, Eric F. Pane, Chris M. Wood

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Humic substances are ubiquitous components of natural waters with important roles in alleviating metal toxicity to aquatic organisms. Recent literature reports suggest that humic substances may also exert direct influences on biota. This study investigated the influence of two commercially available humic substances on sodium metabolism in Daphnia magna, a hyperregulating freshwater crustacean. Environmentally realistic levels of Suwannee River natural organic matter (SRN) and Aldrich humic acid (AHA) significantly enhanced sodium transport. This effect was described as an uncompetitive stimulation of sodium influx, as characterised by an increased maximal sodium transport rate (J max), accompanied by a decreased uptake affinity (increased K m). SRN exposure also significantly promoted the unidirectional loss of sodium from the daphnids to the water, an effect not observed in the presence of AHA. A 24-h preexposure to AHA before influx measurement had no effect on AHA-induced stimulation of sodium influx. Conversely, 24-h preexposure to SRN resulted in influx values that returned to control (humic-free) levels. Whole-body sodium levels reduced by SRN exposure were also restored to control levels following 24-h SRN preexposure. The significance and potential mechanisms of these actions are discussed, and the toxicological implications of these findings are assessed.

Original languageEnglish
Pages (from-to)405-416
Number of pages12
JournalPhysiological and Biochemical Zoology
Volume78
Issue number3
DOIs
StatePublished - May 1 2005

Fingerprint

Daphnia
Humic Substances
Daphnia magna
humic substances
Fresh Water
Metabolism
Crustacea
Sodium
sodium
metabolism
humic acids
Aquatic organisms
Biota
Aquatic Organisms
Water
Level control
aquatic organisms
Rivers
Biological materials
Toxicology

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Physiology
  • Physiology (medical)

Cite this

Humic substances influence sodium metabolism in the freshwater crustacean Daphnia magna. / Glover, Chris N.; Pane, Eric F.; Wood, Chris M.

In: Physiological and Biochemical Zoology, Vol. 78, No. 3, 01.05.2005, p. 405-416.

Research output: Contribution to journalArticle

Glover, Chris N. ; Pane, Eric F. ; Wood, Chris M. / Humic substances influence sodium metabolism in the freshwater crustacean Daphnia magna. In: Physiological and Biochemical Zoology. 2005 ; Vol. 78, No. 3. pp. 405-416.
@article{92bbd6a299764dc8ae45cdde727761ec,
title = "Humic substances influence sodium metabolism in the freshwater crustacean Daphnia magna",
abstract = "Humic substances are ubiquitous components of natural waters with important roles in alleviating metal toxicity to aquatic organisms. Recent literature reports suggest that humic substances may also exert direct influences on biota. This study investigated the influence of two commercially available humic substances on sodium metabolism in Daphnia magna, a hyperregulating freshwater crustacean. Environmentally realistic levels of Suwannee River natural organic matter (SRN) and Aldrich humic acid (AHA) significantly enhanced sodium transport. This effect was described as an uncompetitive stimulation of sodium influx, as characterised by an increased maximal sodium transport rate (J max), accompanied by a decreased uptake affinity (increased K m). SRN exposure also significantly promoted the unidirectional loss of sodium from the daphnids to the water, an effect not observed in the presence of AHA. A 24-h preexposure to AHA before influx measurement had no effect on AHA-induced stimulation of sodium influx. Conversely, 24-h preexposure to SRN resulted in influx values that returned to control (humic-free) levels. Whole-body sodium levels reduced by SRN exposure were also restored to control levels following 24-h SRN preexposure. The significance and potential mechanisms of these actions are discussed, and the toxicological implications of these findings are assessed.",
author = "Glover, {Chris N.} and Pane, {Eric F.} and Wood, {Chris M.}",
year = "2005",
month = "5",
day = "1",
doi = "10.1086/430036",
language = "English",
volume = "78",
pages = "405--416",
journal = "Physiological and Biochemical Zoology",
issn = "1522-2152",
publisher = "University of Chicago",
number = "3",

}

TY - JOUR

T1 - Humic substances influence sodium metabolism in the freshwater crustacean Daphnia magna

AU - Glover, Chris N.

AU - Pane, Eric F.

AU - Wood, Chris M.

PY - 2005/5/1

Y1 - 2005/5/1

N2 - Humic substances are ubiquitous components of natural waters with important roles in alleviating metal toxicity to aquatic organisms. Recent literature reports suggest that humic substances may also exert direct influences on biota. This study investigated the influence of two commercially available humic substances on sodium metabolism in Daphnia magna, a hyperregulating freshwater crustacean. Environmentally realistic levels of Suwannee River natural organic matter (SRN) and Aldrich humic acid (AHA) significantly enhanced sodium transport. This effect was described as an uncompetitive stimulation of sodium influx, as characterised by an increased maximal sodium transport rate (J max), accompanied by a decreased uptake affinity (increased K m). SRN exposure also significantly promoted the unidirectional loss of sodium from the daphnids to the water, an effect not observed in the presence of AHA. A 24-h preexposure to AHA before influx measurement had no effect on AHA-induced stimulation of sodium influx. Conversely, 24-h preexposure to SRN resulted in influx values that returned to control (humic-free) levels. Whole-body sodium levels reduced by SRN exposure were also restored to control levels following 24-h SRN preexposure. The significance and potential mechanisms of these actions are discussed, and the toxicological implications of these findings are assessed.

AB - Humic substances are ubiquitous components of natural waters with important roles in alleviating metal toxicity to aquatic organisms. Recent literature reports suggest that humic substances may also exert direct influences on biota. This study investigated the influence of two commercially available humic substances on sodium metabolism in Daphnia magna, a hyperregulating freshwater crustacean. Environmentally realistic levels of Suwannee River natural organic matter (SRN) and Aldrich humic acid (AHA) significantly enhanced sodium transport. This effect was described as an uncompetitive stimulation of sodium influx, as characterised by an increased maximal sodium transport rate (J max), accompanied by a decreased uptake affinity (increased K m). SRN exposure also significantly promoted the unidirectional loss of sodium from the daphnids to the water, an effect not observed in the presence of AHA. A 24-h preexposure to AHA before influx measurement had no effect on AHA-induced stimulation of sodium influx. Conversely, 24-h preexposure to SRN resulted in influx values that returned to control (humic-free) levels. Whole-body sodium levels reduced by SRN exposure were also restored to control levels following 24-h SRN preexposure. The significance and potential mechanisms of these actions are discussed, and the toxicological implications of these findings are assessed.

UR - http://www.scopus.com/inward/record.url?scp=15944397515&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=15944397515&partnerID=8YFLogxK

U2 - 10.1086/430036

DO - 10.1086/430036

M3 - Article

C2 - 15887087

AN - SCOPUS:15944397515

VL - 78

SP - 405

EP - 416

JO - Physiological and Biochemical Zoology

JF - Physiological and Biochemical Zoology

SN - 1522-2152

IS - 3

ER -