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Award Detail

Doing Business As Name:University of Hawaii
  • Brian N Popp
  • (808) 956-6206
  • Jeffrey C Drazen
Award Date:08/18/2010
Estimated Total Award Amount: $ 426,800
Funds Obligated to Date: $ 426,800
  • FY 2010=$426,800
Start Date:08/15/2010
End Date:07/31/2014
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: CAMEO 2009 - A novel tool for validating trophic position estimates in ecosystem-based fisheries models
Federal Award ID Number:1041329
DUNS ID:965088057
Parent DUNS ID:009438664

Awardee Location

Street:2440 Campus Road, Box 368
Awardee Cong. District:01

Primary Place of Performance

Organization Name:University of Hawaii
Street:2440 Campus Road, Box 368
Cong. District:01

Abstract at Time of Award

Evidence increasingly demonstrates that selective removal of marine life can induce restructuring of marine food webs. Trophic structure is the central component of mass balance models, widely used tools to evaluate fisheries in an ecosystem context. Food web structure is commonly determined by stomach contents or by bulk tissue stable isotope analyses, both of which are limited in terms of resolution and versatility. The investigators will refine a tool, Amino Acid Compound-Specific Isotopic Analyses (AA-CSIA), which can be broadly applicable for quantifying the time-integrated trophic position (TP) of consumers. Differences in source and trophic nitrogen isotopic composition for specific amino acids will provide an unambiguous and integrated measure of fractional trophic TP across multiple phyla, regardless of an animal's physiological condition or of the biogeochemical cycling at the base of the food web. AA-CSIA will allow testing of the efficacy of trophic position estimates derived from ecosystem-based models and promote the evolution of these models into decision-support tools. This project has three goals: 1. To validate the application of AA-CSIA across multiple marine phyla under differing physiological conditions. 2. To compare the application of AA-CSIA across systems with contrasting biogeochemical cycling regimes. 3. To develop the use of AA-CSIA TP estimates for validating trophic models of exploited ecosystems. The investigators will test and refine the approach using a combination of laboratory feeding experiments and field studies across regions with differing biogeochemical cycling regimes. They will determine the applicability of the AA-CSIA approach in a variety of marine organisms assessed in controlled studies. Subsequently, ecosystem components will be sampled from the eastern tropical Pacific, coastal California and the subtropical Pacific gyre. They will also test the effects of sample preservation on the isotopic composition of individual AA to determine whether the approach can be used on archived samples. This tool will allow testing of the efficacy of ecosystem-based models currently used to gain insight into the ecological effects of fisheries removals and improve the reliability of future models required to manage marine resources. In addition to the goal of developing AA-CSIA for use as a TP indicator, the information obtained through this project will provide important species-specific biological data on the feeding behavior of marine organisms that could have implications for their resilience to anthropogenic pressures and climate change. This project will have direct application to evaluating ecosystem effects of fisheries by providing an unbiased, integrated and independent approach to estimating trophic structure, and a method by which to validate existing ecosystem-based model outputs and predictions. In addition, the project will have outreach benefits through the involvement of graduate and undergraduate students, and exposure of younger students through K-12 programs. This research will contribute to the greater understanding of the biology of locally important fish species as well as globally important shrimp and endangered marine turtles.

Publications Produced as a Result of this Research

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O'Malley J. M., Drazen J. C., Popp B. N., Gier E. and Toonen R. J. "Spatial variability in growth and prey availability of lobsters in the northwestern Hawaiian Islands" Marine Ecology Progress Series, v.449, 2012, p.211-220. doi:10.3354/meps09533 

Hannides C. C. S., Popp B. N., Choy C. A., Drazen J. C. "Midwater zooplankton and suspended particle dynamics in the North Pacific substropical gyre: a stable isotope perspective" Limnology and Oceanography, v.58, 2013, p.1931. doi:10.4319/lo.2013.58.6.1931 

O'Malley J. M., Drazen J. C., Popp B. N., Gier E., Toonen R. J. "Spatial variability in growth and prey availability of lobsters n the northwestern Hawaiian Islands" Marine Ecology Progress Series, v.449, 2012, p.211. doi:doi: 10.3354/meps09533 

Vander Zanden H. B., Arthur K. E., Bolten A. B., Popp B. N. Lagueux C. J., Harrison E., Campbell C. L. and Bjorndal K. A. "Trophic ecology of a green turtle breeding population" Marine Ecology Progress Series, v.476, 2013, p.237-249. doi:10.3354/meps10185 

Dale J. J., Wallsgrove N. J., Popp B. N. and Holland K. "Foraging ecology and nursery habitat use of a benthic stringray from stomach content, bulk and amino acid stable isotope analysis" Marine Ecology Progress Series, v.433, 2011, p.221-236. doi:10.3354/meps09171 

Decima M., Landry M. R. and Popp B. N. "Environmental perturbation effects on baseline ?15N values and zooplankton trophic flexibility in the southern California Current Ecosystem" Limnology and Oceanography, v.58, 2013, p.624-634. doi:10.4319/lo.2013.58.2.0624 

Bradley C. J., Madigan D. J., Block B. A., Popp B. N. "Amino acid isotope incorporation and enrichment factors in Pacific bluefin tuna" PLoS ONE, v.9, 2014, p.e85818. doi:10.1371/journal.pone.0085818 

Madigan D. J., Litvin S. Y., Popp B. N., Carlisle A. B., Farwell C. J. and Block B. A. "Tissue turnover rates and isotopic trophic discrimination factors in the endothermic teleost, Pacific Bluefin tuna (Thunnus orientalis)" PLoS ONE, v.7, 2012, p.1-13. doi:10.1371/journal.pone.0049220 

Blum J. D., Popp B. N., Drazen J. C., Choy A. C., Johnson M. W. "Mercury isotope evidence for methylation below the mixed layer in the central North Pacific Ocean" Nature Geoscience, v.6, 2013, p.879. doi:10.1038/NGEO1918 

Seminoff J., Benson S. R., Arthur K. E., Tomoharu E., Dutton P. H., Tapilatu R. F. and Popp B. N. "Stable isotope tracking of endangered sea turtles: Validation with satellite telemetry and ?15N analysis of amino acids" PLoS ONE, v.7, 2012, p.1-11. doi:10.1371/journal.pone.0037403 

Choy C. A., Davison P. C., Drazen J. C., Flynn A., Gier E. J., Hoffman C, McClain-Counts J. P., Miller T. W., Popp B. N., Ross S. W. and Sutton T. T. "Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae) using amino acid nitrogen isotopic analyses" PLoS ONE, v.7, 2012, p.1-8. doi:10.1371/journal.pone.0050133 

Project Outcomes Report


This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Over exploitation of resources continues to be a major threat to the health of marine environments. Over 50% of fisheries are currently considered fully or over exploited, which could potentially alter the structure and stability of these food webs. Ecosystem-based models are essential tools to guide management efforts aimed at restoring or maintaining robust ecosystems and fisheries. The models emphasize the flow of matter through food webs and they use predator-prey relationships based on diet data, generally obtained from analysis of the stomach contents of organisms.  To date, however, there has been no reliable independent method to validate description of trophic structure in these models.  We have tested and applied a new stable isotopic approach that can efficiently provide trophic position estimates of marine consumers from zooplankton to fish and sharks, and in both natural and exploited ecosystems (Figure 1).

Compound-specific nitrogen isotope analysis of amino acids is a technique that avoids many of the short-comings of more traditional stable isotope analyses that are conducted on whole animals or on all the material in a tissue sample.  We examine the isotopic composition of individual amino acids, the building blocks of proteins.  In samples of consumer tissues, individual “source” amino acids such as phenylalanine appear to retain the isotopic composition of nitrogen sources or nutrients at the base of the food web, whereas nitrogen isotope values of “trophic” amino acids such as glutamic acid become substantially higher with each trophic transfer.  Trophic position is estimated from the difference between trophic and source amino acid isotopic compositions and the average shift in isotopic composition with each change in trophic level (Figure 1).  The key advantage of the amino acid isotopic technique is a predator sample alone is sufficient for estimating trophic position, making separate analysis of the isotopic composition of the phytoplankton at the base of the food web unnecessary.

The overarching goal of our research was to develop amino acid compound specific isotopic analysis as a tool that can provide a rapid and unbiased estimate of trophic position for a wide variety of marine organisms (Figure 2) and use this information to validate or correct output from trophic based ecosystem models.  To accomplish this goal, we performed a combination of targeted laboratory experiments with different organisms (shrimp, bluefin tuna, snappers and sharks) and field collections in contrasting marine ecosystems that support major fisheries.  The laboratory studies determined turnover rates of individual amino acids and the robustness of individual amino acid isotopic values in consumer tissues compared to their prey, under varying conditions of food intake and metabolic rate.  These results suggest that the new isotopic method can be applied to consumers regardless if they are young or old, well fed or starving.  The field component focused on organisms from marine environments with distinctly different and varying biogeochemical conditions to examine trophic position for a range of individual species from zooplankton to large fish (Figures 3 & 4).  Our results show that this new approach can be used to accurately estimate trophic position between locations despite differences in ocean biogeochemistry and in a way not possible with conventional isotope analysis.  Currently, our results are being compared to ecosystem model outputs and will assist fisheries managers.  In addition to our original goals, we discovered that the isotopic composition of amino acids can provide unique markers to trace...

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