The gills, adjacent buccopharyngeal epithelium, and skin of the swamp eel Synbranchus marmoratus (Bloch) function for both aerial and aquatic respiration. Aquatic cutaneous O2 uptake occurs continuously at rates that, while dependent upon aquatic 2 tension (PwOO2), are in direct proportion to body surface area. Branchial aquatic O2 uptake takes place during intermittent ventilation which occurs in proportion to body mass. Because of reductions in the body surface area to volume ratio that occur with growth, cutaneous oxygen uptake comprises a larger percentage of the total oxygen uptake of small fish and, to compensate, large fish ventilate more. The mass exponent for total rate of oxygen uptake (Voo2) (0.894 ± 0.145) is within the range predicted from the contributions of cutaneous Voo2 (mass exponent 0.651 ± 0.167) and the number of minutes each hour that branchial ventilation occurs (0.378 ± 0.105). Hyperoxia increases cutaneous VOO2 and reduces branchial ventilation. Total Voo2 was also reduced in hyperoxia and calculations relating this to the reduction in ventilation time yield ventilatory cost estimates that increase with body size and that are high compared to those of other fish when the large component of cutaneous respiration in this species is considered. Large ventilatory costs reflect gill and branchial apparatus specialization for aerial respiration. Accessory cutaneous respiration and intermittent aquatic ventilation reduce these costs, and intermittent gill use in aquatic breathing, which is the exact analogue of the pattern for branchial respiratory use during air breathing, seems to optimize aquatic O2 uptake with minimal ventilatory cost.
In the field: an interview with Harald Wolf
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In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
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Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
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After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
Ecotourism affecting iguana glucose tolerance
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Ecotourists feeding grapes on skewers to north Bahamian rock iguanas may be doing the reptiles more harm than good as the sugar charged diet is giving the animals high blood sugar.
Evolution of metabolic plasticity
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In their Commentary, Frank Seebacher and Julian Beaman propose that metabolic plasticity originated in prebiotic protocells and that it was a pre-requisite for effective transfer of genetic material across generations – the hallmark of Darwinian evolution.
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