Center for BioComplexity News – Fall 2015

Sandra Milburn for PEI ・ High Meadows Environmental Institute

CBC Hosts Two Meetings

The Center for BioComplexity (CBC) recently hosted two meetings, the first of which was the annual meeting of the NSF-funded Coupled Natural-Human Systems Research Project (Social-Ecological Complexity and Adaptation in Marine Systems) Group, organized and chaired by James Watson (Stockholm Resilience Centre) and CBC director Simon A. Levin. Participants came to Princeton from New Zealand, Hawaii, Seattle, and Sweden on June 1st to discuss their work on social capital in marine systems, focusing on understanding how social networks emerge among fishers, and how this information can be used to promote self-organized sustainable collective-action agreements. They concentrated on synthesizing mathematical and computational modeling, with data drawn from interviews with fishermen.

Coupled Natural-Human Systems Research Project 2015 Annual Meeting Participants

CBC Research and Recent Publications

CBC scientists have been tackling a number of issues with profound short- and long-term consequences for society and the planet, for example, the global rise of antimicrobial consumption in both animals and humans. As Thomas Van Boeckel (former CBC postdoc, now a postdoctoral fellow at Zurich University and the Swiss Federal Institute of Technology) points out, antibiotics are one of the cornerstones of modern medicine; they have reduced the burden of common infectious diseases and become essential for many medical interventions as well as animal production. However, as a result of overconsumption, antibiotic-resistant pathogens have emerged and spread among humans and animals. Van Boeckel, with Simon A. Levin, Bryan Grenfell (Princeton), and Ramanan Laxminarayan (The Center for Disease Dynamics, Economics, and Policy, Washington DC) have set about quantifying the global growth in antimicrobial consumption in humans and animals.  In two recent studies published in the Lancet Infectious Diseases and PNAS respectively, they conclude that antimicrobial consumption in humans increased by 36% in humans from 2000-2010 and is expected to grow by as much as 67% in animals by 2030. While western countries currently have the highest rates of antimicrobial consumption, both studies identified fast-growing economies (BRICS: Brazil, Russia, India, China and South Africa) as the drivers of this unprecedented growth and antimicrobial consumption, raising concern regarding the growing antibiotic resistance threat in these regions.

Other CBC researchers have been examining the expansion of aquaculture production to meet the growing global seafood demand (half of the seafood we now consume comes from farms). Headed by Dane Klinger (CBC postdoc), in collaboration with Simon A. Levin and James Watson, the goal of this project is to understand the emerging role of offshore aquaculture, where fish are farmed in the open-ocean rather than on land. Through biophysical and economic modeling, Klinger and his colleagues are investigating how much the ocean could contribute to global food production as well as where offshore farms might be sited to minimize negative environmental impacts and conflicts with other ocean uses. Furthermore, they are attempting to characterize interactions between farmed and wild seafood (for example, do consumers discriminate between wild and farmed seafood) and how these interactions could lead to perverse incentives to overfish or operate polluting farms.

Still other CBC researchers, led by Ben Morin (CBC collaborating postdoc; Arizona State University) and in collaboration with Simon A. Levin and others, have been looking at private disease-risk mitigation effort as a function of the cost of mitigation and of the illness itself. According to these scientists, interventions that change this cost may be used to alter private risk mitigation decisions. In recent publications in the Journal of Theoretical Biology and Theoretical Ecology, Morin et al. model the potential for instruments that affect the cost of illness to alter private mitigation behavior in such a way as to yield net social benefits. Where the disease is not very infectious or the duration of illness is short, they show that it may be socially optimal to promote private mitigation effort by increasing the cost of illness. By contrast, where the disease is highly infectious or long-lasting, it may be optimal to discourage private mitigation by reducing the cost of disease. That is, under some circumstances, society would prefer shorter, more intense epidemics without avoidance costs in contrast with longer, less intense epidemics with avoidance costs.  There is a region in moderately-valued parameter space where the relationship is more complicated – moderately infectious disease with moderate infectious periods are co-dependently sensitive to changes in either. This implies that basic reproduction numbers are not sufficient to categorize which economic instrument is socially optimal.

New Faces at the CBC

Lastly, the CBC welcomes Helene Muller-Landau (see photo), staff scientist at the Smithsonian Tropical Research Institute in Panama, who is on sabbatical at Princeton for the 2015-16 academic year.  While at the CBC, she will work on improving modeling of tropical forest woody plant communities and ecosystems through a combination of model development, parameterization, and testing informed by quantitative analyses of large-scale empirical datasets.

Helene Muller Landau

Note: CBC research discussed in this article was supported by grants from the National Science Foundation; Princeton Institute for International and Regional Studies (PIIRS); Science and Technology Directorate, Department of Homeland Security; Princeton University, Grand Challenges Program; The National Institutes of Health; and Nordforsk.