Brovkin, V.

Reick, C.

van Bodegom, P.

English

MPG.PuRe

European biospheric network takes off

Brovkin, V. 

Eos, Vol. 91, No. 17, 27 April 2010The huge amount of recently acquired information about the functioning of the terrestrial biosphere and the ever increas-ing spatial resolution of Earth system mod-els call for a new level of integrating efforts among biosphere modelers, developers of ecological theory, and data- gathering com-munities. Responding to this call, a new European network, Terrestrial Biosphere in the Earth System ( TERRABITES), held its opening symposium in Germany. The meeting was organized jointly with another recently founded European net-work, Advancing the Integrated Monitoring of Trace Gas Exchange Between Biosphere and Atmosphere (ABBA). Almost 100 scientific contributions covered the latest advances in modeling ecophysiological and biogeochemi-cal processes; analyses of model constraints set by measurements of water and carbon dioxide (CO2) fluxes, including carbon iso-topes; and new perspectives in using remote sensing data for evaluation of global terres-trial biosphere models. Several presentations underlined chal-lenges in using the growing amount of ground- based ecological observations for better quantification of vegetation processes on different scales. A key talk introduced the TRY database, which currently contains more than 2.4 million plant trait records with a focus on 47 key traits such as leaf nitro-gen content and litter decomposition rates. Subsequent presentations demonstrated how accounting for trait variability within plant functional types affects the behavior of dynamic global vegetation models and forest gap models. Other presenters took a more radical approach and showed how optimality analysis could predict trait values for a given set of environmental conditions and how trait values could be applied to pre-dicting plant functional types. Implementing fire occurrences into global biosphere and Earth system mod-els is another challenging task. Recent results from the Spread and Intensity of Fire ( SPITFIRE) model suggest that changes in wood usage for fuel by humans could alter the future trend in fire- related CO2 emis-sons. Another modeling study found a weak upward trend in twentieth- century fire emis-sions, in contrast to previous inventory- based estimates that suggested a stronger increase in emissions. Comparison of model results with recent satellite- based products on burned area not only identified regions for model improvement but also stressed remarkable differences among various satel-lite products. Presentations of the remote sensing com-munity, organized by specialists from the European Space Agency, focused on the challenge of providing the global model-ing community with reliable data. An over-view talk highlighted recent advances in shifts in Earth system feedbacks, helping researchers to project global changes and anticipate their effects on society.AcknowledgmentWe thank Ariel Mack for the graphic design of Figure 1. Support was provided by the Biosphere 2 Philecology Foundation, U.S. Department of Agriculture, U.S. National Sci-ence Foundation GK-12, Science Founda-tion Arizona, U.S. Geological Survey (USGS) Global Change Program (Western Moun-tain Initiative), U.S. Department of Ener-gy’s National Institute for Climate Change Research, Office of Science (Biological and Environmental Research), and Los Alamos National Laboratory/Laboratory Directed Research and Development (LANL/LDRD). ReferencesAdams, H. D., et al. (2009a), Temperature sensitiv-ity of drought- induced tree mortality portends increased regional die- off under global- change- type drought, Proc. Natl. Acad. Sci. U. S. A., 106(17), 7063–7066, doi:10.1073/pnas.0901438106.Adams, H. D., et al. (2009b), Reply to Sala: Tempera-ture sensitivity in drought- induced tree mortality hastens the need to further resolve a physiologi-cal model of death, Proc. Natl. Acad. Sci. U. S. A., 106(26), E69, doi:10.1073/pnas.0905282106.Adams, H. D., et al. (2009c), Reply to Leuzinger et al.: Drought- induced tree mortality temperature sensi-tivity requires pressing forward with best available science, Proc. Natl. Acad. Sci. U. S. A., 106(38), E107, doi:10.1073/pnas.0909227106.Allen, C. D., and D. D. Breshears (1998), Drought- induced shift of a forest- woodland ecotone: Rapid landscape response to climate variation, Proc. Natl. Acad. Sci. U. S. A., 95(25), 14,839–14,842, doi:10.1073/ pnas.95.25.14839.Allen, C. D., et al. (2010), A global overview of drought and heat- induced tree mortality reveals emerging climate change risks for forests, For. Ecol. Manage., 259(4), 660–684, doi:10.1016/ j .foreco.2009.09.001.Berg, E. E., J. D. Henry, C. L. Fastie, A. D. De Volder, and S. M. Matsuoka (2006), Spruce beetle out-breaks on the Kenai Peninsula, Alaska, and Kluane National Park and Reserve, Yukon Terri-tory: Relationship to summer temperatures and regional differences in disturbance regimes, For. Ecol. Manage., 227(3), 219–232, doi:10.1016/ j .foreco.2006.02.038.Bonan, G. B. (2008), Forests and climate change: Forcings, feedbacks, and the climate benefits of forests, Science, 320(5882), 1444–1449, doi:10.1126/science.1155121.Breshears, D. D., et al. (2005), Regional vegetation die- off in response to global- change- type drought, Proc. Natl. Acad. Sci. U. S. A., 102(42), 15,144–15,148, doi:10.1073/pnas.0505734102.Chapin, F. S., J. T. Randerson, A. D. McGuire, J. A. Foley, and C. B. Field (2008), Changing feedbacks in the climate- biosphere system, Front. Ecol. Envi-ron., 6(6), 313–320, doi:10.1890/ 080005.Kelly, A. E., and M. L. Goulden (2008), Rapid shifts in plant distribution with recent climate change, Proc. Natl. Acad. Sci. U. S. A., 105(33), 11,823–11,826, doi:10.1073/pnas.0802891105.Kurz, W. A., G. Stinson, G. J. Rampley, C. C. Dymond, and E. T. Neilson (2008a), Risk of natural distur-bances makes future contribution of Canada’s forests to the global carbon cycle highly uncertain, Proc. Natl. Acad. Sci. U. S. A., 105(5), 1551–1555, doi:10.1073/pnas.0708133105.Kurz, W. A., et al. (2008b), Mountain pine beetle and forest carbon feedback to climate change, Nature, 452(7190), 987–990, doi:10.1038/ nature06777.Leuzinger, S., C. Bigler, A. Wolf, and C. Korner (2009), Poor methodology for predicting large- scale tree die- off, Proc. Natl. Acad. Sci. U. S. A., 106(38), E106, doi:10.1073/pnas.0908053106.Malhi, Y., et al. (2009), Exploring the likelihood and mechanism of a climate- change induced dieback of the Amazon rainforest, Proc. Natl. Acad. Sci. U. S. A., 106(49), 20,610–20,615, doi:10.1073/ pnas.0804619106.McDowell, N., et al. (2008), Mechanisms of plant survival and mortality during drought: Why do some plants survive while others succumb to drought?, New Phytol., 178(4), 719–739, doi:10.1111/  j.1469- 8137.2008.02436.x.Phillips, O. L., S. L. Lewis, T. R. Baker, K. J. Chao, and N. Higuchi (2008), The changing Amazon for-est, Philos. Trans. R. Soc. B, 363(1498), 1819–1827, doi:10.1098/ rstb.2007.0033.Phillips, O. L., et al. (2009), Drought sensitivity of the Amazon rainforest, Science, 323(5919), 1344–1347, doi:10.1126/science.1164033.Raffa, K. F., et al. (2008), Cross- scale drivers of natu-ral disturbances prone to anthropogenic ampli-fication: The dynamics of bark beetle eruptions, BioScience, 58(6), 501–517, doi:10.1641/B580607.Rotenberg, E., and D. Yakir (2010), Contribution of semi- arid forests to the climate system, Science, 327(5964), 451–454, doi:10.1126/ science.1179998.Sala, A. (2009), Lack of direct evidence for the carbon- starvation hypothesis to explain drought- induced mortality in trees, Proc. Natl. Acad. Sci. U. S. A., 106(26), E68, doi:10.1073/pnas.0904580106.Sala, A., F. Piper, and G. Hoch (2010), Physiological mechanisms of drought- induced tree mortality are far from being resolved, New Phytol., 186(2), 274–281, doi:10.1111/j.1469-8137.2009.03167.x.van Mantgem, P. J., et al. (2009), Widespread increase of tree mortality rates in the western Unit-ed States, Science, 323(5913), 521–524, doi:10.1126/science.1165000.Author InformationHenry D. Adams, Alison K. Macalady, and David D. Breshears, University of Arizona, Tucson;  E-mail:  henry@ email . arizona . edu; Craig D. Allen, USGS, Los Alamos, N. M.; Nathan L. Stephenson, USGS, Three Rivers, Calif.; Scott R. Saleska and Travis E. Hux-man, University of Arizona, Tucson; and Nathan G. McDowell, LANL, Los Alamos, N. M.MEETINGSEuropean Biospheric Network Takes OffOpening Symposium of the TERRABITES Network; Hamburg, Germany, 9–11 February 2010PAGE 155Eos, Vol. 91, No. 17, 27 April 2010Substantial uncertainty exists in projec-tions of future sea level rise, due primarily to a lack of understanding about ice sheet dynamics. Paleo Constraints on Sea Level Rise ( PALSEA) is a working group of the Past Global Changes ( PAGES) project and the International Marine Global Change Studies ( IMAGES) program that aims to extract infor-mation about ice sheet response to tempera-ture change by examining the history of sea level over the Quaternary (spanning the past ~2.5 million years). In particular,  PALSEA focuses on the past 800,000 years, particu-larly interglacial periods, with a range of temperatures bracketing the modern.PALSEA recently held a workshop at Woods Hole Oceanographic Institution (WHOI). Funded by  IMAGES,  PAGES, and WHOI’s Ocean and Climate Change Insti-tute, the workshop focused on challenges in  uranium- thorium ( U-Th) coral dating. The meeting also included a public outreach event, “Where land and sea meet: Managing shoreline change over the next 100 years,” funded by WHOI’s Morss Colloquium.Discussion at the workshop encom-passed three themes. The first theme covered technical issues in  U-Th mass spec-trometry. As new developments in mass spectrometry continue to improve analyti-cal precision, ensuring comparability of ages reported by different labs becomes crucial. Ideally, all measurements should be traceable to the same set of reference standards. Unfortunately, internationally recognized standards are not currently available. The consensus at the  PALSEA workshop was that the time is ripe for the development of such standards, and a strategy for their production and distribu-tion is under way, drawing on the experi-ences of  EARTHTIME, an international ini-tiative aimed at integrating high- precision geochronology and quantitative chrono-stratigraphy (http:// www . earth -time .org).The meeting included an informal  U-Th dating interlab comparison involving 14 labs. Aliquots of mineral solutions (aragonite, ura-ninite) and powder (carbonate) were distrib-uted and measured. The insight gained from this exercise was very useful, and a more comprehensive intercomparison is being planned.Another theme covered was the open-system behavior of  U-series nuclides. The impact of  open- system behavior on age quality is well known, yet best prac-tices for sample screening and age cor-rection are still keenly debated.  PALSEA workshop participants considered these key points: (1) Multiple replicates are cru-cial for establishing the uncertainty associ-ated with sample heterogeneity; (2) strati-graphic consistency is useful for evaluating ages, and publications should include more stratigraphic detail; and (3) uniform initial 234U/238U criteria should be adopted for qual-ity assurance and correction methods.The third theme discussed was the devel-opment of a Quaternary sea level database. Relative sea level histories permit the recon-struction of former ice sheets, a fundamen-tal boundary condition for modeling past climate.  PALSEA suggests the following ice sheet guidelines for the Paleo climate Mod-elling Intercomparison Project (PMIP): (1) Alternative ice sheet boundary condi-tions, generated by independent glacial iso-static adjustment (GIA) models, must be considered. (2) An existing database (see A. S. Dyke et al., Quat. Sci. Rev., 21, 9–31, 2002) that uses evidence of ice sheet extent should be used. (3) GIA models use differ-ent relative sea level databases, many with inconsistent or outdated reconstructions. To address this problem,  PALSEA will develop an  open- access,  quality- controlled, and  self-  consistent database of relative sea level for use in isostatic models.—W. G. Thompson, WHOI, Woods Hole, Mass.;  E-mail:  wthompson@ whoi .edu; and M. B. Andersen, University of Bristol, Bristol, UKmultisensor and multiangular techniques that, together with the latest improvements in accurate modeling of radiative proper-ties of vegetation, allow for the retrieval of a broad range of vegetation properties at the leaf, canopy, and stand levels. Other pre-sentations stressed the importance of data assimilation techniques to include observa-tional data into Earth system models.The TERRABITES and ABBA networks, funded by the intergovernmental frame-work for European Cooperation in Sci-ence and Technology (COST), plan to con-tinue to organize symposia and workshops for the next 4 years. Scientists from North America as well as other parts of the globe are welcome to take part in these meetings to ensure international cooperation. More information is available at the network Web sites http:// www . terrabites .net and http:// www . ileaps .org/ multisites/ cost0804.—VicTor BroVkin and chrisTiAn reick, Max Planck Institute for Meteorology, Hamburg, Ger-many; E-mail: victor . brovkin@ zmaw .de; and peTer VAn BodeGom, Vrije Universiteit Amsterdam, Amsterdam, NetherlandsFacilitating Progress on the Quaternary History of Sea Level ChangeUnderstanding Future Sea Level Rise:  The Challenges of Dating Past Interglacials; Woods Hole, Massachusetts, 20–25 September 2009PAGE 155

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European biospheric network takes off

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