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Dr. Travis Meador

Archived Page

This web page has not been updated since the former colleague left MARUM.

What it is that I do here: an elevator conversation

Firstly, can you appreciate the importance of plant life for the planet? ...Over centuries we have learned the relative importance and cultivation practices of many plant species: for crops, medicine, decoration, architecture, etc. Perhaps most importantly, plants on land and in the ocean are a natural sustenance that take carbon from the atmosphere, turn it into living biomass, and produce the oxygen that we breathe.

EQUALLY IMPORTANT as carbon assimilation by photosynthesis, is the removal of organic carbon via degradation of living biomass. Humans have also learned to benefit from this natural process; examples include composting, treating wastewater, and even brewing!

WE HAVE ONLY BEGUN to explore the many varieties of carbon degradation mechanisms on Earth. I am currently researching these and other capabilities of micro-organisms in marine sediments...

RESEARCH INTERESTS

  • Organic Geochemistry
  • Molecular Microbiology
  • Biogeochemical Cycles
Curriculum Vitae 2015 (765.8 kB)

EDUCATION & EMPLOYMENT

2016-presentResearch AssociateUniversity of Bremen, MARUM Center for Marine Environmental SciencesBremen, Germany
2010 - 2015Postdoctoral InvestigatorUniversity of Bremen, MARUM Center for Marine Environmental SciencesBremen, Germany
2008-2010Postdoctoral InvestigatorWoods Hole Oceanographic InstitutionWoods Hole, MA, USA
2008Postdoctoral InvestigatorUniversity of the AegeanMytilini, Greece
2001-2008Ph.D. OceanographyUniveristy of California, San Diego, Scripps Institution of OceanographyLa Jolla, CA, USA
1997-2001B.S. Marine SciencesUniversity of South CarolinaColumbia, SC, USA

CURRENT PROJECTS

Planktonic Archaeal Phosphorus Affinity & Apportionment (PAPAA)

I am leading a project to assess the role of archaeal nitrifiers in the marine phosphorus cycle by (i) quantifying the uptake and partitioning of P and directly comparing these values to that of pelagic bacteria, and (ii) by employing novel isolation and chemical characterization techniques to identify individual P-containing macromolecules.

Biogeochemical Networks of the Deep Biosphere

The generation of large OTUs, geochemistry, lipidomic datasets has allowed for scientists to explore the relationship and potential drivers of microbial life below the seafloor. Using multi-variate analysis techniques, I am coordinating the results and efforts of a team of scientists to identify diagnostic trends in the distribution of microbes and their cell membrane biomarkers.

Funded by the Deutsche Forschungsgemeinschaft

Funded by the European Research Council

COMPLETED PROJECTS

Global Lipid Survey: White Oak River estuary, NC, USA

This estuary has been shown to harbor large communities of the obscure Miscellaneous Crenarchaea Group. In October 2010, together with scientists at the Univeristy of North Carolina - Chapel Hill and a MARUM postdoc stationed at this campus (C. Lazar), we collected estuarine sediment cores to explore the distribution of MCG and its intact polar lipid signatures, as well as the geochemical anomolies that give rise to their dominance of the archaeal community. In addition, we are working with microbiologists at the University of Regensburg to establish the first laboratory culture of MCG.

Associate researchers: Dr. Andreas Teske (UNC), Dr. Casandre Lazar (UNC), Dr. Howard Mendlovitz (UNC), Dr. Emma Gagen (Univ. Regensburg), Nadine Goldenstein (Univ. Bremen), Gina Kuippers (Univ. Bremen)

The archaeal lipidome in estuarine sediment dominated by members of the Miscellaneous Crenarchaeotal Group

Dynamics of IPLs in Archaea cultures

To investigate the significance of intact polar lipid head group and core lipid compositions, we are working together with Dr. Emma Gagen and a team of researchers at University of Regensburg who manipulate the culture conditions of selected Archaea. These experiments identify changes in IPL composition in response to cellular metabolic activity.

Associate researchers: Prof. Dr. Michael Thomm (Univ. Regensburg), Dr. Emma Gagen (Univ. Regensburg), Nadine Goldenstein (Univ. Bremen), Gina Kuippers (Univ. Bremen)

 

 

 

 

Thermococcus kodakarensis modulates its polar membrane lipids and elemental composition according to growth stage and phosphate availability

Stable Isotope Probing (SIP)

We assess production of sedimentary Bacteria and Archaea by measuring the uptake of 13C and deuterium stable isotope labels into lipid biomarkers during controlled anoxic incubations. Corresponding measurements of geochemical and nucleic acid biomarkers provide enormous potential to investigate the activity of the uncultured organisms in a variety of environments. Our current experiments have focused on the Miscelaneous Crenarchaeota, who are enriched in the White Oak River sediments, bacterial communities in tidal flat sediments, and branched GDGT producing organisms in peat.

Associate researchers: Gina Kuippers (Univ. Manchester), Weichao Wu (MARUM, Univ. Bremen) Dr. Martin Könneke (MARUM, Univ. Bremen), Dr. Cassandre Lazar (UNC), Dr. Andreas Teske (UNC), Dr. Arnaud Huguet (CNRS, Paris France)

Push coring the White Oak River

Fermenters at Uni-Regensburg

Preparing incubations in the anoxic chamber

ONGOING RESEARCH THEMES

courtesy of Oliver Chrystossek (www.olive-r.eu)
Dissolved organic matter (DOM) is a black box of organic molecules in both the logistical sense, that we vaguely understand how it cycles but do not know the underlying mechanisms that control this cycling, and in the aeronautical sense, that DOM records the molecular “conversations” of events that have transpired. Indeed, DOM is often depicted as a central component in marine food webs, having important ties to all domains of life and the global C cycle; however, the processes that control its distributions and fluxes remain poorly defined and further investigation of its composition and reactivity is necessary to resolve environmental phenomena and anthropogenic forcings.

PUBLICATIONS

* co-first author contribution
** publication with student
  1. Meador T.B., Goldenstein N.I., Gogou A., Herut B., Psarra S., Tsagaraki T.M. and Hinrichs K-U., (2017) Planktonic Lipidome Responses to Aeolian Dust Input in Low-Biomass Oligotrophic Marine Mesocosms. Frontiers in Marine Science 4(113). doi: 10.3389/fmars.2017.00113
  2. Huguet, A.*, Meador, T.B.*, Laggoun-Défarge, F., Könneke, M., Derenne, S., Hinrichs, K-U., (2017) Production rates of bacterial tetraether lipids and fatty acids in peatland under varying oxygen concentrations. Geochimica et Cosmochimica Acta 203, 103-116. doi: 10.1016/j.gca.2017.01.012
  3. B. Herut, E.Rahav, T. M. Tsagaraki, A. Giannakourou, A. Tsiola, S. Psarra, A. Lagaria,N. Papageorgiou, N. Mihalopoulos, C.N. Theodosi, E. Stathopoulou, M. Scoullos,M.D. Krom, A. Stockdale, Z. Shi,I. Berman-Frank, T.B. Meador, T. Tanaka, C. Shun-Yan, K. Violaki, G. Cui, H. Liu, P. Pitta, (2016) The potential impact of Saharan dust and polluted aerosols on microbial populations in the East Mediterranean Sea, an overview of a mesocosm experimental approach. Frontiers in Marine Science 3,226. doi: 10.3389/fmars.2016.00226
  4. Yoshinaga, M.Y., Gagen, E.J., Wörmer, L., Broda N.K., Meador, T.B., Wendt, J., Thomm, M., Hinrichs, K-U., (2015) Methanothermobacter thermautotrophicus modulates its membrane lipids in response to hydrogen and nutrient variability. Frontiers in Microbiology, doi: 10.3389/fmicb.2015.00005
  5. Meador, T.B., Bowles, M., Lazar, C., Zhu, C., Teske, A., Hinrichs, K-U., (2015) The archaeal lipidome in estuarine sediment dominated by members of the Miscellaneous Crenarchaeotal Group. Environmental Microbiology, doi: 10.1111/1462-2920.12716
  6. Lazar, C.S., Biddle, J.F., Meador, T.B., Blair, N., Hinrichs, K-U., Teske, A.P., (2015) Environmental controls on intragroup diversity of the uncultured benthic archaea of the Miscellaneous Crenarchaeotal Group lineage naturally enriched in anoxic sediments of the White Oak River Estuary (North Carolina, USA). Environmental Microbiology, doi: 10.1111/1462-2920.12659
  7. Meador, T.B. and L.I. Aluwihare, (2014) Biological production in the Amazon River plume imparts compositional changes to ultrafiltered dissolved organic matter. Global Biogeochemical Cycles, doi: 10.1002/2013GB004778
  8. Meador, T.B., Gagen, E.J., Loscar, M.E.**, Goldhammer, T., Yoshinaga, M.Y., Wendt, J., Zabel, M., Thomm, M., Hinrichs, K-U., (2014) Thermococcus kodakarensis modulates its polar membrane lipids and elemental composition according to growth stage and phosphate availability. Frontiers in Microbiology, 5, 10. doi: 10.3389/fmicb.2014.00010
  9. Meador, T.B., Zhu, C., Elling, F., Könneke, M., Hinrichs, K-U., (2014) Identification of isoprenoidal glycosidic glycerol dibiphytanol diethers and indications for their biosynthetic origin. Organic Geochemistry, 69, 70-75. doi: 10.1016/j.orggeochem.2014.02.00
  10. Zhu, C., Meador, T.B., Dummann, W., Hinrichs, K-U., (2014) Identification of unusual butanetriol dialkyl glycerol tetraether and pentanetriol dialkyl glycerol tetraether lipids in marine sediments. Rapid Communications in Mass Spectrometry 28, 332-338. doi: 10.1002/rcm.6792
  11. Zhu, R.*, Lin, Y.-S., Lipp, J.S., Meador, T.B., and Hinrichs, K.-U., (2014) Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment. Biogeosciences 11, 4869-4880. doi:10.5194/bg-11-4869-2014
  12. Gagen, E. J., Huber, H., Meador, T., Hinrichs, K.-U., Thomm, M., (2013) Novel Cultivation-Based Approach To Understanding the Miscellaneous Crenarchaeotic Group (MCG) Archaea from Sedimentary Ecosystems. Applied and Environmental Microbiology, 79, 6400-6406. doi: 10.1128/aem.02153-13
  13. Jones, V., Meador, T.B., Gogou, A., Migon, C., Penkman, K.E.H., Collins, M.J., Repeta, D.J., (2013) Characterisation and dynamics of dissolved organic matter in the Northwestern Mediterranean Sea. Progress in Oceanography. doi: 10.1016/j.pocean.2013.06.007
  14. Meador, T.B.; Gogou, A.; Spyres, G.; Herndl, G.J.; Krasakopoulou, E.; Psarra, S.; Yokokawa, T.; De Corte, D.; Zervakis, V.; Repeta, D., (2010) Biogeochemical relationships between ultrafiltered dissolved organic matter and picoplankton activity in the Eastern Mediterranean Sea. Deep Sea Research II 57, 1460-1477. doi: 10.1016/j.dsr2.2010.02.015
  15. Frangoulis, C.; Psarra, S.; Zervakis, V.; Meador, T. ; Mara, P.; Gogou, A.; et al., (2010) Connecting plankton food web functioning and biogeochemical cycles in the Mediterranean area affected by the Black Sea water inflow. Journal of Plankton Research 32, 1203-1216. doi: 10.1093/plankt/fbq010
  16. Aluwihare, L.I. and T.B. Meador, (2008) Chemical composition of marine dissolved organic nitrogen. In Nitrogen in the Marine Environment, 2nd Edition, edited by Capone, D.G.; Bronk, D.A.; Mulholland, M.R.; Carpenter, E.J., Elsevier, San Diego. doi: 10.1016/B978-0-12-372522-6.00003-7
  17. Meador, T.B.; Aluwihare, L.I.; and Mahaffey, C., (2007) Isotopic heterogeneity and cycling of components of the dissolved organic nitrogen pool in the oligotrophic ocean. Limnology and Oceanography 52(3), 934-947. doi: 10.4319/lo.2007.52.3.0934