title: Behavioural thermoregulation in Daphnia carinata from different depths of a natural water body: influence of environmental oxygen levels and temperature.
abstract: The influence of environmental parameters (water temperature and dissolved oxygen content) on the haemoglobin content of a naturally occurring population of Daphnia carinata was studied in a population resident in an intermittently flowing, shallow body of water. It was found that the Hb content of the animals was influenced by a combination of both the water temperature and dissolved oxygen profiles of the water body. In Summer, stratification, as indicated by sampling at three depths, constrained thermoregulatory behaviour; Hb-poor animals from the upper levels of the water column chose a lower temperature in hypoxia than their Hb-rich counterparts from greater depth. In Winter, the water column was mixed and remained moderately hypoxic at all times. Due to the low temperature of the water, Hb-contents in winter were much lower than those found in Summer. Overall, it was found that thermoregulatory behaviour in D. carinata is dependent upon Hb-content, which is strongly influenced by the animals' environment.
authors.affiliation: Department of Zoology, La Trobe University, Melbourne 3086, Australia.
authors.forename: P R
authors.initials: PR
authors.lastname: Wiggins
authors.forename: P B
authors.initials: PB
authors.lastname: Frappell
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D003621:Daphnia / Q000502:physiology*; D017753:Ecosystem; D005618:Fresh Water / Q000737:chemistry; D006454:Hemoglobins / Q000378:metabolism; D000860:Hypoxia / Q000503:physiopathology; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D012621:Seasons; D013696:Temperature
chemical_list: D006454:Hemoglobins; D010100:Oxygen