Matching Items (105)
ContributorsWebster, Preston T. (Author) / Riordan, Nathaniel A. (Author) / Gogineni, Chaturvedi (Author) / Liu, Shi (Author) / Lu, Jing (Author) / Zhao, Xin-Hao (Author) / Smith, David J. (Author) / Zhang, Yong-Hang (Author) / Johnson, Shane R. (Author)
Created2014
Description
Nitrogen (N) and/or phosphorus (P) availability can limit growth of primary producers across most of the world's aquatic and terrestrial ecosystems. These constraints are commonly overcome in agriculture by applying fertilizers to improve yields. However, excessive anthropogenic N and P inputs impact natural environments and have far-reaching ecological and evolutionary consequences, from individual species up to entire ecosystems. The extent to which global N and P cycles have been perturbed over the past century can be seen as a global fertilization experiment with significant redistribution of nutrients across different ecosystems. Here we explore the effects of N and P availability on stoichiometry and genomic traits of organisms, which, in turn, can influence: (i) plant and animal abundances; (ii) trophic interactions and population dynamics; and (iii) ecosystem dynamics and productivity of agricultural crops. We articulate research priorities for a deeper understanding of how bioavailable N and P move through the environment and exert their ultimate impacts on biodiversity and ecosystem services.
ContributorsGuignard, Maite S. (Author) / Leitch, Andrew R. (Author) / Acquisti, Claudia (Author) / Eizaguirre, Christophe (Author) / Elser, James (Author) / Hessen, Dag O. (Author) / Jeyasingh, Punidan D. (Author) / Neiman, Maurine (Author) / Richardson, Alan E. (Author) / Soltis, Pamela S. (Author) / Soltis, Douglas E. (Author) / Stevens, Carly J. (Author) / Trimmer, Mark (Author) / Weider, Lawrence J. (Author) / Woodward, Guy (Author) / Leitch, Ilia J. (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor)
Created2017-07-06
Description
The growth rate hypothesis predicts that organisms with higher maximum growth rates will also have higher body percent phosphorus (P) due to the increased demand for ribosomal RNA production needed to sustain rapid growth. However, this hypothesis was formulated for invertebrates growing at the same temperature. Within a biologically relevant temperature range, increased temperatures can lead to more rapid growth, suggesting that organisms in warmer environments might also contain more P per gram of dry mass. However, since higher growth rates at higher temperature can be supported by more rapid protein synthesis per ribosome rather than increased ribosome investment, increasing temperature might not lead to a positive relationship between growth and percent P. We tested the growth rate hypothesis by examining two genera of Neotropical stream grazers, the leptophlebiid mayfly Thraulodes and the bufonid toad tadpole Rhinella. We measured the body percent P of field-collected Thraulodes as well as the stoichiometry of periphyton resources in six Panamanian streams over an elevational gradient spanning approximately 1,100 m and 7°C in mean annual temperature. We also measured Thraulodes growth rates using in situ growth chambers in two of these streams. Finally, we conducted temperature manipulation experiments with both Thraulodes and Rhinella at the highest and lowest elevation sites and measured differences in percent P and growth rates. Thraulodes body percent P increased with temperature across the six streams, and average specific growth rate was higher in the warmer lowland stream. In the temperature manipulation experiments, both taxa exhibited higher growth rate and body percent P in the lowland experiments regardless of experimental temperature, but growth rate and body percent P of individuals were not correlated. Although we found that Thraulodes from warmer streams grew more rapidly and had higher body percent P, our experimental results suggest that the growth rate hypothesis does not apply across temperatures. Instead, our results indicate that factors other than temperature drive variation in organismal percent P among sites.
ContributorsMoody, Eric (Author) / Rugenski, Amanda (Author) / Sabo, John (Author) / Turner, Benjamin L. (Author) / Elser, James (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2017-04-18
Description
For many species, migration evolves to allow organisms to access better resources. However, the proximate factors that trigger these developmental changes, and how and why these vary across species, remain poorly understood. One prominent hypothesis is that poor-quality food promotes development of migratory phenotypes and this has been clearly shown for some polyphenic insects. In other animals, particularly long-distance bird migrants, it is clear that high-quality food is required to prepare animals for a successful migration. We tested the effect of diet quality on the flight behaviour and morphology of the Mongolian locust, Oedaleus asiaticus. Locusts reared at high population density and fed low-N grass (performance-enhancing for this species) had enhanced migratory morphology relative to locusts fed high-N grass. Furthermore, locusts fed synthetic diets with an optimal 1 : 2 protein : carbohydrate ratio flew for longer times than locusts fed diets with lower or higher protein : carbohydrate ratios. In contrast to the hypothesis that performance-degrading food should enhance migration, our results support the more nuanced hypothesis that high-quality diets promote development of migratory characteristics when migration is physiologically challenging.
ContributorsCease, Arianne (Author) / Harrison, Jon (Author) / Hao, Shuguang (Author) / Niren, Danielle (Author) / Zhang, Guangming (Author) / Kang, Le (Author) / Elser, James (Author) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor)
Created2017-06-07
ContributorsBeaudoin, M. (Author) / Johnson, Shane R. (Author) / Boonzaayer, Martin D. (Author) / Zhang, Yong-Hang (Author) / Johs, B. (Author)
Created1999
ContributorsJohnson, Shane R. (Author) / Grassi, E. (Author) / Beaudoin, M. (Author) / Boonzaayer, Martin D. (Author) / Tsakalis, K. S. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsBraun, W. (Author) / Möller, H. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsDowd, P. (Author) / Braun, W. (Author) / Smith, David J. (Author) / Ryu, C. M. (Author) / Guo, C.-Z. (Author) / Chen, S.-L. (Author) / Koelle, U. (Author) / Johnson, Shane R. (Author) / Zhang, Yong-Hang (Author)
Created1999
ContributorsJohnson, Shane R. (Author) / Dowd, P. (Author) / Braun, W. (Author) / Koelle, U. (Author) / Ryu, C. M. (Author) / Beaudoin, M. (Author) / Guo, C.-Z. (Author) / Zhang, Yong-Hang (Author)
Created2000
ContributorsBeaudoin, M. (Author) / Grassi, E. (Author) / Johnson, Shane R. (Author) / Ramaswamy, K. (Author) / Tsakalis, K. (Author) / Alford, T. L. (Author) / Zhang, Yong-Hang (Author)
Created2000