Linked Life Data

11809782

Source:http://linkedlifedata.com/resource/pubmed/id/11809782

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 23
pubmed:dateCreated
2002-1-25
pubmed:abstractText
Heart rate and dive behaviour were monitored in double-crested cormorants (Phalacrocorax auritus) during shallow (1 m) and deep diving (12 m), after breathing different gas mixtures, to investigate the role of depth and the accompanying changes in blood gas levels in cardiac and behavioural control during voluntary diving. Pre-dive heart rate in both shallow- and deep-diving birds was approximately three times the resting heart rate (137.9+/-17.5 beats min(-1); mean +/- S.D., N=5), falling abruptly upon submersion to around 200-250 beats min(-1). During shallow diving, the initial reduction in heart rate was followed by a secondary, more gradual decline, to around the resting level. In contrast, during deep diving, heart rate stabilised at 200-250 beats min(-1). In dives of similar duration, mean dive heart rate was significantly lower during shallow diving (163.2+/-14.0 beats min(-1)) than during deep diving (216.4+/-7.7 beats min(-1)), but in both cases was significantly above the resting value. The difference in cardiac response is probably due to an increase in arterial oxygen tension (Pa(O(2))) during the descent phase of deep dives (compression hyperoxia). Exposure to a hyperoxic gas mixture before shallow diving significantly increased mean dive heart rate, while exposure to a hypoxic gas mixture in both the shallow and deep dive tanks significantly reduced mean dive heart rate. In contrast, breathing hypercapnic gas before diving had no significant effect on dive heart rate. We suggest that the cardiac response to voluntary diving in double-crested cormorants is strongly influenced by changes in blood oxygen levels throughout the dive. Dive duration was unaffected by alterations in inspired gas composition, but surface interval duration decreased during hyperoxic gas exposure and increased during hypoxic gas exposure. The most efficient dive pattern (highest dive/pause ratio) was observed after hyperoxic exposure. Our study suggests that blood oxygen level is a powerful stimulus that facilitates the cardiac and behavioural adjustments during foraging that are important components of a strategy allowing double-crested cormorants to maximise the time spent under water and, hence, potential foraging time.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-0949
pubmed:author
pubmed:issnType
Print
pubmed:volume
204
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4081-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
The effects of depth on the cardiac and behavioural responses of double-crested cormorants (Phalacrocorax auritus) during voluntary diving.
pubmed:affiliation
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4. manfred.enstipp@c-strasbourg.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't