Tropical flatback turtle (Natator depressus) embryos are resilient to the heat of climate change

Howard, Robert, Bell, Ian, and Pike, David A. (2015) Tropical flatback turtle (Natator depressus) embryos are resilient to the heat of climate change. Journal of Experimental Biology, 218 (20). pp. 3330-3335.

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Abstract

Climate change is threatening reproduction of many ectotherms by increasing nest temperatures, potentially making it more difficult for females to locate nest sites that provide suitable incubation regimes during embryonic development. Elevated nest temperatures could increase the incidence of embryonic mortality and/or maladaptive phenotypes. We investigated whether elevated nest temperatures reduce hatching success in tropical flatback turtles (Natator depressus) nesting in the Gulf of Carpentaria, Australia. Egg incubation treatments began at 29.5 degrees C and progressively increased in temperature throughout incubation, up to maxima of 31, 32, 33, 34 and 35 degrees C. Elevated nest temperatures did not reduce hatching success or hatchling body size relative to control temperatures (29.5 degrees C), but did speed up embryonic development. A combination of sudden exposure to high temperatures during the first 2 weeks of incubation (>36 degrees C for 48 h) and prolonged warming throughout incubation (from 29.5-35 degrees C) did not reduce hatching success. We also recorded an unusually high pivotal sex-determining temperature in this flatback turtle population relative to other sea turtle populations: an equal ratio of male and female hatchlings is produced at similar to 30.4 degrees C. This adaptation may allow some flatback turtle populations to continue producing large numbers of hatchlings of both sexes under the most extreme climate change scenarios. Some tropical populations of nesting flatbacks may possess important adaptations to high-temperature incubation environments, which are not found in more southerly temperate populations.

Item ID: 41950
Item Type: Article (Refereed Research - C1)
Keywords: embryonic development, hatching success, lethal thermal limits, marine turtle, metabolic heating, thermal mortality, thermal tolerance
ISSN: 1477-9145
Date Deposited: 08 Dec 2015 18:12
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 70%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060208 Terrestrial Ecology @ 30%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960301 Climate Change Adaptation Measures @ 70%
95 CULTURAL UNDERSTANDING > 9503 Heritage > 950302 Conserving Aboriginal and Torres Strait Islander Heritage @ 30%
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