Skip to main content
eScholarship
Open Access Publications from the University of California

The Role of Oxygen in Determining Upper Thermal Limits in Lottia digitalis under Air Exposure and Submersion.

  • Author(s): Bjelde, Brittany E
  • Miller, Nathan A
  • Stillman, Jonathon H
  • Todgham, Anne E
  • et al.

Published Web Location

https://doi.org/10.1086/682220
Abstract

Oxygen limitation of aerobic metabolism is hypothesized to drive organismal thermal tolerance limits. Differences in oxygen availability in air and water may underlie observed differences in upper thermal tolerance of intertidal limpets if oxygen is limiting in submerged environments. We explored how cardiac performance (heart rate, breakpoint temperature [BPT], flat-line temperature [FLT], and temperature sensitivity) was affected by hyperoxia and hypoxia in the finger limpet, Lottia digitalis, under air exposure and submersion. Upper thermal tolerance limits were unchanged by increasing availability of oxygen, although air-exposed limpets were able to maintain cardiac function to higher temperatures than submerged limpets. Maximum heart rate did not increase with greater partial pressure of oxygen (Po2), suggesting that tissue Po2 levels are likely maximized during normoxia. Hypoxia reduced breakpoint BPTs and FLTs in air-exposed and submerged limpets and accentuated the difference in BPTs between the two groups through greater reductions in BPT in submerged limpets. Differences in respiratory structures and the degree to which thermal limits are already maximized may play significant roles in determining how oxygen availability influences upper temperature tolerance.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
Current View