USAP-DC

Beginning with the earliest expeditions to the poles, scientists have noted that many polar taxa grow to unusually large body sizes, a phenomenon now known as 'polar gigantism.' Although scientists have been interested in polar giants for many years, many questions still remain about the biology of this significant form of polar diversity. This award from the Antarctic Organisms and Ecosystems program within the Polar Sciences Division at the National Science Foundation will investigate the respiratory and biomechanical mechanisms underlying polar gigantism in Antarctic pycnogonids (commonly known as sea spiders). The project will use a series of manipulative experiments to investigate the effects of temperature and oxygen availability on respiratory capacity and biomechanical strength, and will compare Antarctic sea spiders to related species from temperate and tropical regions. The research will provide insight into the ability of polar giants to withstand the warming polar ocean temperatures associated with climate change.

The prevailing hypothesis to explain the evolution of gigantism invokes shifts in respiratory relationships in extremely cold ocean waters: in the cold, oxygen is more plentiful while at the same time metabolic rates are very low. Together these effects alleviate constraints on oxygen supply that restrict organisms living in warmer waters. Respiratory capacity must evolve in the context of adaptive tradeoffs, so for organisms including pycnogonids there must be tradeoffs between respiratory capacity and resistance to biomechanical stresses. The investigators will test a novel hypothesis that respiratory challenges are not associated with particular body sizes, and will answer the following questions: What are the dynamics of oxygen transport and consumption in Antarctic pycnogonids; how do structural features related to oxygen diffusion trade off with requirements for body support and locomotion; how does body size influence vulnerability to environmental hypoxia and to temperature-oxygen interactions; and does the cold-driven high oxygen availability in the Antarctic raise the limit on body size by reducing trade-offs between diffusivity and structural integrity? The research will explore the effects of increased ocean temperatures upon organisms that have different body sizes. In addition, it will provide training for graduate and undergraduate students affiliated with universities in EPSCOR states.

Person	Role
Moran, Amy	Investigator
Woods, H. Arthur	Co-Investigator

Antarctic Organisms and Ecosystems

Award # 1341476

USAP-1341476_1

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Physiological and biochemical measurements on Pycnogonida from McMurdo Sound	None	exist
USAP-DC	Cuticle morphology and oxygen gradients of Antarctic sea spiders	None	exist
USAP-DC	Size scaling of oxygen physiology and metabolic rate of Antarctic sea spiders	None	exist
USAP-DC	Physiological, biomechanical, and locomotory data on Antarctic sea spiders fouled and unfouled with epibionts	None	exist

1. Lane, S. J., Tobalske, B. W., Moran, A. L., Shishido, C. M., & Woods, H. A. (2018). Costs of epibionts on Antarctic sea spiders. Marine Biology, 165(8). (doi:10.1007/s00227-018-3389-9)
2. Moran, A. L., Woods, H. A., Shishido, C. M., Lane, S. J., & Tobalske, B. W. (2018). Predatory behavior of giant Antarctic sea spiders (Colossendeis) in nearshore environments. Invertebrate Biology, 137(2), 116–123. (doi:10.1111/ivb.12210)
3. Shishido, C. M., Woods, H. A., Lane, S. J., Toh, M. W. A., Tobalske, B. W., & Moran, A. L. (2019). Polar gigantism and the oxygen–temperature hypothesis: a test of upper thermal limits to body size in Antarctic pycnogonids. Proceedings of the Royal Society B: Biological Sciences, 286(1900), 20190124. (doi:10.1098/rspb.2019.0124)
4. Woods, H. A., & Moran, A. L. (2020). Reconsidering the Oxygen–Temperature Hypothesis of Polar Gigantism: Successes, Failures, and Nuance. Integrative and Comparative Biology. (doi:10.1093/icb/icaa088)
5. Woods, H. A., Moran, A. L., Tobalske, B. W., Lane, S. J., & Shishido, C. L. (2016). Temperature‐Oxygen Interactions and the Evolution of Giant Antarctic Sea Spiders. The FASEB Journal, 30(S1). (doi:10.1096/fasebj.30.1_supplement.1230.1)
6. Moran, A. L., Harasewych, M. G., Miller, B. A., Woods, H. A., Tobalske, B. W., & Marko, P. B. (2019). Extraordinarily long development of the Antarctic gastropod Antarctodomus thielei (Neogastropoda: Buccinoidea). Journal of Molluscan Studies, 85(3), 319–326. (doi:10.1093/mollus/eyz015)
7. Lane, S. J., Shishido, C. M., Moran, A. L., Tobalske, B. W., Arango, C. P., & Woods, H. A. (2017). Upper limits to body size imposed by respiratory–structural trade-offs in Antarctic pycnogonids. Proceedings of the Royal Society B: Biological Sciences, 284(1865), 20171779. (doi:10.1098/rspb.2017.1779)