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2011 Annual Science Report

Massachusetts Institute of Technology Reporting  |  SEP 2010 – AUG 2011

Executive Summary

Our team’s primary focus this past year has been on evaluations of habitability. This work extends from the Earth’s past when complex life first appeared, to Mars and onwards to extrasolar planets.

Habitability of extrasolar planets
Using data from the Kepler mission and new ground-based detections, Lisa Kaltenegger and Dimitar Sasselov have identified potential and confirmed candidate planets that orbit within the Habitable Zone and could thus provide environments for basic and complex life to develop. They have also developed atmosphere models for extrasolar planetary environments for different geological cycles and varied environments that might permit the advent of complex life. The team modeled detectable spectral features that identify such planetary environments for future NASA missions like the James Webb Space Telescope.

Astrobiological Exploration of Mars
The Mars Science Laboratory (MSL) mission, due for launch on November 25th, 2011, has four primary science objectives that are aimed at detecting habitable environments in the vicinity of Gale Crater on Mars: assess the biological potential of at least one target environment by determining the nature and inventory of organic carbon compounds; characterize the geology of the landing region at all appropriate spatial scales by investigating the chemical, isotopic, and mineralogical composition of the surface and near-surface materials; investigate planetary processes of relevance to past habitability, including the role of water and carbon dioxide; and characterize the broad spectrum of surface radiation. Project scientist John Grotzinger and other MIT NAI team members have been contributing to numerous aspects of site selection, site evaluation and the optimal environments for biosignature formation and preservation.

Environments of early complex organisms
Understanding the rise of complex organisms, including animals, near the end of the Precambrian (p€) eon is one of the major problems in earth history. This rise to prominence begins overtly in the Ediacaran period around 580 million years ago and truly blossoms in the Cambrian Period about 530 million years ago. The radiation of complex life depended on new ecological interactions, including vertical tiering and predation, which in turn depended upon the continuing oxygenation of the world’s oceans. Our latest results suggest that predation by unicellular organisms (protists) likely originated very early in the Neoproterozoic, hundreds of millions of years before we see the first evidence of multicellularity.

A primary focus of MIT team members is to analyze the sedimentary record for molecular and isotopic signals that tell us about Neoproterozoic aquatic environments and the communities that inhabited them. The results of our studies suggest that marine anoxic and euxinic sedimentary environments were extensive and widespread and that redox gradients in Neoproterozoic oceans were likely steep. While this constrains the spatial distribution of early metazoa, along with their need for oxygen, it also provides clues about the potential use of redox chemistry by sessile multicellular organisms for harvesting energy prior to the advent of motility and predation. For example, several new collaborative studies arose out of our team’s 2009 field trip to Mistaken Point, Newfoundland. Sediments that now outcrop along the edge of the Avalon Peninsula were deposited in deep, slow-moving waters, at depths where light could not penetrate. Communities of fossil fronds preserved here reached up off the bottom, much like plants, but are thought to have lived by absorbing reduced compounds through their large surface area. In a study led by David Jacobs, vertical tiering in rangeomorphs communities is shown to create water flow regimes near to the sea bottom that break down diffusional limits and significantly enhance nutrient availability. Another study, led by Eric Sperling, suggests that the Mistaken Point rangeomorph Thectardis (Porifera?) utilized dissolved organic carbon in the Ediacaran ocean. These opportunities are only available to larger-sized organisms, and this size advantage is exclusive to multicellular eukaryotes – not to competing bacteria with their smaller cell-size, and minimal multicellularity. Thus rangeomorph communities, with advantages stemming from their multicellular form, represent an important step in the evolution of complex multicellular life. Other paleonotological studies conduced by our team propose specific mechanisms that enabled preservation of soft-bodied organisms.

Unicellular protists abound in the Neoproterozoic
One of the highlights of our team’s work was led by Tanja Bosak (MIT) working with Sare Pruss (Smith College), Francis Macdonald (Harvard U.) and Dan Lahr (U. Sao Paolo). They discovered fossils of microscopic eukaryotes in limestone and dolostone strata deposited between the two Neoproterozoic low-latitude glaciations (between ~ 716 and 635 million years ago). These fossils include amoeba-like organisms that incorporated mineral-rich particles from the environment into their shells, mineral-rich shells of the oldest putative foraminiferans, and thick flask-shaped organic envelopes of the first putative ciliates, representatives of a major group of modern eukaryotes. These fossils demonstrate a previously unrecognized record of body fossils during the ~ 70 million years between the two “Snowball Earth” episodes and document the increasing diversity of morphologically and compositionally modern eukaryotes before the rise of complex animals.

Molecular basis for complexity development
Molecular investigations have revealed the genes and the gene interactions that appear to be necessary for the advent of complex life, and what needs to be lost in order for complex life to become secondarily simplified. Together the fossil record and the molecular record indicate that evolving complex life involves both new genes and new ecologies within the context of permissive environmental circumstances. Meanwhile, at UC Berkeley, MIT team member Nicole King has compared animal genomes with genomes from their closest living relatives, the choanoflagellates to reconstruct the genome composition of the last common ancestor of animals.

Development of sensory systems
One of the defining features of animals is that many interact with the world through complex sensory structures (eyes, ears, antennas, etc.), which are coordinated by collections of neurons. While the nervous and sensory systems of animals are incredibly diverse, a growing body of evidence suggests that many of these systems are controlled by similar sets of genes. We are looking at early branching and understudied lineages of the animal family tree (using the jellyfish Aurelia and the worm Neanthes respectively) to see if these animals use similar genes during neurosensory development as the better-studied fruit fly and mouse. This research is critical for determining which structures are shared between animals because of common ancestry (known as homologous structures) and those that evolved independently in different lineages. Ultimately, such research informs how morphologically and behaviorally complex animals evolve.

Carbon cycling
The rock record late Neoproterozoic (540-800 Ma) appears to exhibit strong
perturbations to Earth’s carbon cycle. These have been typically interpreted as a signal for an unusually dynamic carbon cycle associated with the Neoproterozoic ventilation of the oceans. The so-called ‘Shuram Excursion’, which is also seen in the Wonoka, Doushantuo and Johnnie formations, is one of the most enigmatic of these perturbations with multiple competing hypotheses that include localized diagenetic effects, a global diagenetic ‘event’ to proposal that it reflects carbon cycle dynamics unique to the Neoproterozoic (Grotzinger et al., 2011). The project led by Daniel Rothman at MIT seeks an understanding of the mechanisms that drive such events and their biogeochemical significance. The dynamics of the Rothman-Hayes-Summons (2003) model are incompatible with the Fike-Grotzinger-Pratt-Summons (2006) interpretation of the Shuram excursion. The reason: the negative shift and its recovery almost surely take millions of years, and dynamical considerations require it to be no longer than tens of thousands of years. So far, the inception and duration of Shuram Excursion have eluded all efforts at dating and, hence, a satisfying resolution remains elusive.

The coincidence between the largest isotopic perturbations in the Neoproterozoic geological record to the carbon cycle, weathering and redox proxies, and climate suggest mechanistic links. Studies by Francis Macdonald, David Johnston and other team members have taken a new look at well-preserved geological sections in Mongolia and the Northwest Territories of Canada. Their results indicate that the extreme weathering of the continents in the aftermath of low-latitude glaciations delivered unprecedented amounts of radiogenic Sr and phosphorous to the oceans, stimulating productivity, burial, and the rise of free oxygen. Ongoing work focuses on better constraining the timing of these events with U/Pb geochronology and their relationship to the micropaleontological record of the diversification of eukaryotes.

Since the geological records of these perturbations are relatively rare and can be corrupted by the effects of thermal metamorphism we look to analogous transitional episodes, such as oceanic anoxic events (OAEs), during the Phanerozoic, and modern environments, to gain additional insights. For example, Ann Pearson (Harvard) and colleagues have looked at the role of eukaryotes vs. prokaryotes in Cretaceous Ocean Anoxic Events. Dominant eukaryotic export production during ocean anoxic events reflects the importance of recycled ammonium. They used measurements of the nitrogen isotopic composition of pigments to distinguish between different primary producers within surface ocean communities and are following up by searching for a mechanistic explanation for these N-isotopic fractionations.

The Permian-Triassic Mass Extinction provides another opportunity to examine the links between carbon cycle dynamics and the rise and fall of complex life. New and extensive high-precision U-Pb dating conducted in the Bowring Laboratory reveals that the extinction peak occurred just before 252.28 ± 0.08 Ma, following a decline of 2‰ in the δ13C of marine dissolved inorganic carbon over 90,000 years, and coincided with a δ13C excursion of -5‰ that is estimated to have lasted ≤20,000 years. The entire extinction interval was less than 200,000 years, and synchronous in marine and terrestrial realms. These results will soon appear in a major paper in Science Magazine.

Inverse carbon isotope patterns of lipids and kerogen are a characteristic of Neoproterozoic organic matter as well as organic matter deposited at OAE’s including the Permian-Triassic Mass Extinction. A new paper from the Pearson lab on carbon export production presents a model that suggests carbon isotopic signatures preserved in the Neoproterozoic could have been highly controlled by the relative ratio of eukaryotic to prokaryotic export production. They are currently using data from a set of water-column filtrates obtained from the Eastern Tropical North Pacific Ocean to test this model.

Metabolic networks
Members of the Segre’ group use systems biology approaches to study the complex network of metabolic reactions that allow microbial cells to survive and reproduce under varying environmental conditions. The resource allocation problem that underlies these fundamental processes changes dramatically when multiple cells can compete or cooperate with each other, for example through metabolic cross-feeding. Through mathematical models of microbial ecosystems and computer simulations of spatially structured cell populations, the Segre’ team are developing improved understanding of the environmental conditions and evolutionary processes that favor the emergence of multicellular organization.

Education and Public Outreach
EPO lead Phoebe Cohen has had a busy and successful year promoting and our aims and accomplishments to the broader community. Using NAI Central funds, Phoebe and other MIT team members collaborated with a MIT youth astronomy group consisting of four Boston public high school students and four recent BPS graduates to create the exhibit, which was displayed at MIT for 4 days and at the MIT Museum for 8 days. Approximately 1,000 people saw the exhibit during its run and parts of the exhibit will continue to be used throughout the year at other local outreach events.

A second major initiative is ‘Telling Your Story: Workshops to Promote Scientist-Teacher Partnerships’. The theme of these one-day workshops is to bring together local K-12 teachers and researchers to learn from each other – scientists learn how to best communicate their work to K-12 audiences, and teachers learn about cutting edge research. By the end of the workshop, partnerships are formed that result in classroom visits by scientists. We are running these workshops in partnership with other educators at MIT and Harvard as well as the Cambridge Science Festival. We have run two workshops in 2011 and will run another one or two in the coming year. MIT team members also played a big role in MIT’s 150th Anniversary Open House and in April’s week-long Cambridge Science Festival.

In partnership with the Encyclopedia of Life, we helped produce two podcasts on the Ediacaran fossils of Newfoundland and Australia. The Newfoundland podcast was picked up nationally by NPR’s All Things Considered. MIT Team members are contributing to a lecture and discussion series at the MIT Museum entitled ‘Life in the Universe’.

We continued our collaborative effort with the ASU team and Australian Centre for Astrobiology to develop a series of Virtual Field Trips. The first VFT on the Ediacaran of Australia is now in testing and revision, and we organized a major field trip to Hamelin Pool, Western Australia which included collecting media and content for a second VFT on stromatolites and the rise of oxygen on early earth.

Publications

  • Alegado, R. A., Grabenstatter, J. D., Zuzow, R., Morris, A., Huang, S. Y., Summons, R. E., & King, N. (2012). Algoriphagus machipongonensis sp. nov., co-isolated with a colonial choanoflagellate. INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 63(Pt 1), 163–168. doi:10.1099/ijs.0.038646-0

  • Arvidson, R. E., Ashley, J. W., Bell, J. F., Chojnacki, M., Cohen, J., Economou, T. E., … Wolff, M. J. (2011). Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater. Journal of Geophysical Research, 116. doi:10.1029/2010je003746

  • Bosak, T., Lahr, D. J. G., Pruss, S. B., MacDonald, F. A., Dalton, L., & Matys, E. (2011). Agglutinated tests in post-Sturtian cap carbonates of Namibia and Mongolia. Earth and Planetary Science Letters, 308(1-2), 29–40. doi:10.1016/j.epsl.2011.05.030

  • Bosak, T., Lahr, D. J. G., Pruss, S. B., MacDonald, F. A., Gooday, A. J., Dalton, L., & Matys, E. D. (2011). Possible early foraminiferans in post-Sturtian (716-635 Ma) cap carbonates. Geology, 40(1), 67–70. doi:10.1130/g32535.1

  • Bosak, T., MacDonald, F., Lahr, D., & Matys, E. (2011). Putative Cryogenian ciliates from Mongolia. Geology, 39(12), 1123–1126. doi:10.1130/g32384.1

  • Campbell, L. I., Rota-Stabelli, O., Edgecombe, G. D., Marchioro, T., Longhorn, S. J., Telford, M. J., … Pisani, D. (2011). MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda. Proceedings of the National Academy of Sciences, 108(38), 15920–15924. doi:10.1073/pnas.1105499108

  • Campo-Paysaa, F., Sémon, M., Cameron, R. A., Peterson, K. J., & Schubert, M. (2011). microRNA complements in deuterostomes: origin and evolution of microRNAs. Evolution & Development, 13(1), 15–27. doi:10.1111/j.1525-142×.2010.00452.x

  • Chakrabarti, R., Knoll, A. H., Jacobsen, S. B., & Fischer, W. W. (2012). Si isotope variability in Proterozoic cherts. Geochimica et Cosmochimica Acta, 91, 187–201. doi:10.1016/j.gca.2012.05.025

  • Close, H. G., Bovee, R., & Pearson, A. (2011). Inverse carbon isotope patterns of lipids and kerogen record heterogeneous primary biomass. Geobiology, 9(3), 250–265. doi:10.1111/j.1472-4669.2011.00273.x

  • Dahl, T. W., Canfield, D. E., Rosing, M. T., Frei, R. E., Gordon, G. W., Knoll, A. H., & Anbar, A. D. (2011). Molybdenum evidence for expansive sulfidic water masses in ~750Ma oceans. Earth and Planetary Science Letters, 311(3-4), 264–274. doi:10.1016/j.epsl.2011.09.016

  • Erwin, D. H. (2011). Evolutionary uniformitarianism. Developmental Biology, 357(1), 27–34. doi:10.1016/j.ydbio.2011.01.020

  • Erwin, D. H. (2011). Novelties That Change Carrying Capacity. J. Exp. Zool. (Mol. Dev. Evol.), 318(6), 460–465. doi:10.1002/jez.b.21429

  • Erwin, D. H., & Tweedt, S. (2011). Ecological drivers of the Ediacaran-Cambrian diversification of Metazoa. Evol Ecol, 26(2), 417–433. doi:10.1007/s10682-011-9505-7

  • Erwin, D. H., Laflamme, M., Tweedt, S. M., Sperling, E. A., Pisani, D., & Peterson, K. J. (2011). The Cambrian Conundrum: Early Divergence and Later Ecological Success in the Early History of Animals. Science, 334(6059), 1091–1097. doi:10.1126/science.1206375

  • Gill, B. C., Lyons, T. W., Young, S. A., Kump, L. R., Knoll, A. H., & Saltzman, M. R. (2011). Geochemical evidence for widespread euxinia in the Later Cambrian ocean. Nature, 469(7328), 80–83. doi:10.1038/nature09700

  • Grotzinger, J. P., Fike, D. A., & Fischer, W. W. (2011). Enigmatic origin of the largest-known carbon isotope excursion in Earth’s history. Nature Geosci, 4(5), 285–292. doi:10.1038/ngeo1138

  • Heimberg, A. M., Cowper-Sal{middle Dot}lari, R., Semon, M., Donoghue, P. C. J., & Peterson, K. J. (2010). microRNAs reveal the interrelationships of hagfish, lampreys, and gnathostomes and the nature of the ancestral vertebrate. Proceedings of the National Academy of Sciences, 107(45), 19379–19383. doi:10.1073/pnas.1010350107

  • Higgins, M. B., Robinson, R. S., Husson, J. M., Carter, S. J., & Pearson, A. (2012). Dominant eukaryotic export production during ocean anoxic events reflects the importance of recycled NH4+. Proceedings of the National Academy of Sciences, 109(7), 2269–2274. doi:10.1073/pnas.1104313109

  • Higgins, M. B., Wolfe-Simon, F., Robinson, R. S., Qin, Y., Saito, M. A., & Pearson, A. (2011). Paleoenvironmental implications of taxonomic variation among δ15N values of chloropigments. Geochimica et Cosmochimica Acta, 75(22), 7351–7363. doi:10.1016/j.gca.2011.04.024

  • Johnston, D. T., MacDonald, F. A., Gill, B. C., Hoffman, P. F., & Schrag, D. P. (2012). Uncovering the Neoproterozoic carbon cycle. Nature, 483(7389), 320–323. doi:10.1038/nature10854

  • Kaltenegger, L., & Sasselov, D. (2011). EXPLORING THE HABITABLE ZONE FOR KEPLER PLANETARY CANDIDATES. The Astrophysical Journal, 736(2), L25. doi:10.1088/2041-8205/736/2/l25

  • Kaltenegger, L., Segura, A., & Mohanty, S. (2011). MODEL SPECTRA OF THE FIRST POTENTIALLY HABITABLE SUPER-EARTH—Gl581d. The Astrophysical Journal, 733(1), 35. doi:10.1088/0004-637x/733/1/35

  • Klitgord, N., & Segrè, D. (2010). Environments that Induce Synthetic Microbial Ecosystems. PLoS Computational Biology, 6(11), e1001002. doi:10.1371/journal.pcbi.1001002

  • Klitgord, N., & Segrè, D. (2011). Ecosystems biology of microbial metabolism. Current Opinion in Biotechnology, 22(4), 541–546. doi:10.1016/j.copbio.2011.04.018

  • Knoll, A. H. (2011). The Multiple Origins of Complex Multicellularity. Annual Review of Earth and Planetary Sciences, 39(1), 217–239. doi:10.1146/annurev.earth.031208.100209

  • Laflamme, M., Flude, L. I., & Narbonne, G. M. (2012). Ecological Tiering and the Evolution of a Stem: The Oldest Stemmed Frond from the Ediacaran of Newfoundland, Canada. Journal of Paleontology, 86(2), 193–200. doi:10.1666/11-044.1

  • Laflamme, M., Schiffbauer, J. D., Narbonne, G. M., & Briggs, D. E. G. (2010). Microbial biofilms and the preservation of the Ediacara biota. Lethaia, 44(2), 203–213. doi:10.1111/j.1502-3931.2010.00235.x

  • Parfrey, L. W., Lahr, D. J. G., Knoll, A. H., & Katz, L. A. (2011). Estimating the timing of early eukaryotic diversification with multigene molecular clocks. Proceedings of the National Academy of Sciences, 108(33), 13624–13629. doi:10.1073/pnas.1110633108

  • Philippe, H., Brinkmann, H., Copley, R. R., Moroz, L. L., Nakano, H., Poustka, A. J., … Telford, M. J. (2011). Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature, 470(7333), 255–258. doi:10.1038/nature09676

  • Pisani, D., Feuda, R., Peterson, K. J., & Smith, A. B. (2012). Resolving phylogenetic signal from noise when divergence is rapid: A new look at the old problem of echinoderm class relationships. Molecular Phylogenetics and Evolution, 62(1), 27–34. doi:10.1016/j.ympev.2011.08.028

  • Pruss, S. B., Bosak, T., MacDonald, F. A., McLane, M., & Hoffman, P. F. (2010). Microbial facies in a Sturtian cap carbonate, the Rasthof Formation, Otavi Group, northern Namibia. Precambrian Research, 181(1-4), 187–198. doi:10.1016/j.precamres.2010.06.006

  • Ratti, S., Knoll, A. H., & Giordano, M. (2011). Did sulfate availability facilitate the evolutionary expansion of chlorophyll a+c phytoplankton in the oceans?. Geobiology, 9(4), 301–312. doi:10.1111/j.1472-4669.2011.00284.x

  • Schütte, M., Skupin, A., Segrè, D., & Ebenhöh, O. (2010). Modeling the complex dynamics of enzyme-pathway coevolution. Chaos: An Interdisciplinary Journal of Nonlinear Science, 20(4), 045115. doi:10.1063/1.3530440

  • Shen, S-Z., Crowley, J. L., Wang, Y., Bowring, S. A., Erwin, D. H., Sadler, P. M., … Jin, Y-G. (2011). Calibrating the End-Permian Mass Extinction. Science, 334(6061), 1367–1372. doi:10.1126/science.1213454

  • Sim, M. S., Bosak, T., & Ono, S. (2011). Large Sulfur Isotope Fractionation Does Not Require Disproportionation. Science, 333(6038), 74–77. doi:10.1126/science.1205103

  • Sim, M. S., Ono, S., Donovan, K., Templer, S. P., & Bosak, T. (2011). Effect of electron donors on the fractionation of sulfur isotopes by a marine Desulfovibrio sp.. Geochimica et Cosmochimica Acta, 75(15), 4244–4259. doi:10.1016/j.gca.2011.05.021

  • Sperling, E. A., Peterson, K. J., & Laflamme, M. (2010). Rangeomorphs, Thectardis (Porifera?) and dissolved organic carbon in the Ediacaran oceans. Geobiology, 9(1), 24–33. doi:10.1111/j.1472-4669.2010.00259.x

  • Sperling, E. A., Pisani, D., & Peterson, K. J. (2011). Molecular paleobiological insights into the origin of the Brachiopoda. Evolution & Development, 13(3), 290–303. doi:10.1111/j.1525-142×.2011.00480.x

  • Summons, R. E., Amend, J. P., Bish, D., Buick, R., Cody, G. D., Des Marais, D. J., … Sumner, D. Y. (2011). Preservation of Martian Organic and Environmental Records: Final Report of the Mars Biosignature Working Group. Astrobiology, 11(2), 157–181. doi:10.1089/ast.2010.0506

  • Tosca, N. J., Johnston, D. T., Mushegian, A., Rothman, D. H., Summons, R. E., & Knoll, A. H. (2010). Clay mineralogy, organic carbon burial, and redox evolution in Proterozoic oceans. Geochimica et Cosmochimica Acta, 74(5), 1579–1592. doi:10.1016/j.gca.2009.12.001

  • Waldbauer, J. R., Newman, D. K., & Summons, R. E. (2011). Microaerobic steroid biosynthesis and the molecular fossil record of Archean life. Proceedings of the National Academy of Sciences, 108(33), 13409–13414. doi:10.1073/pnas.1104160108

  • Winchell, C. J., Valencia, J. E., & Jacobs, D. K. (2010). Expression of Distal-less, dachshund, and optomotor blind in Neanthes arenaceodentata (Annelida, Nereididae) does not support homology of appendage-forming mechanisms across the Bilateria. Dev Genes Evol, 220(9-10), 275–295. doi:10.1007/s00427-010-0346-0

  • Bush, A.M., Bambach, R.K. & Erwin, D.H.  (2011).  Ecospace utilization during the Ediacaran radiation and the Cambrian Eco-plosion.  In: LaFlamme, M., Schiffbauer, J. & Dornbos, S. (Eds.).  Quantifying the Evolution of Early Life.  Vol. Topics in Geobiology.  Springer.
  • Close, H.G., Wakeham, S.G. & Pearson, A.  (2011, In Preparation).  Microbial contributions to export production in the ETNP.
  • Creveling, J., Johnston, D.T. & Knoll, A.H.  (2011).  Geochemical controls on phosphatization taphonomy in the Middle Cambrian.  Geological Society of America, 43(5): 53.
  • Darroch, S., Laflamme, M., Schiffbauer, J.D. & Briggs, D.E.G.  (Accepted).  Experimental Formation of a Microbial Death Mask.  Palaios.
  • Dornbos, S.Q., Clapham, M.E., Fraiser, M.L. & Laflamme, M.  (In Press).  Lessons from the Fossil Record: The Ediacaran Radiation, the Cambrian Radiation, and the End-Permian Mass Extinction [Book Chapter].  Marine Biodiversity Futures and Ecosystem Functioning frameworks, methodologies and integration.
  • Erwin, D.H. & Valentine, J.W.  (In Presss).  The Cambrian Explosion: The Construction of Animal Biodiversity.  Ben Roberts.
  • Erwin, D.H.  (2011).  A Paleontologist looks at history.  Cliodynamics, 2: 27-39.
  • Ghisalberti, M., Jacobs, D.K., Gold, D.A., Laflamme, M., Clapham, M.E., Narbonne, G., Johnston, D.T. & Summons, R.  (2011).  Canopy Flow Models Identify A Scaling Advantage For Large Size In The Mistaken Point Rangeomorphs, The Worlds Oldest Community Of Multicellular Eukaryotes.  Geological Society of America Annual Meeting.  Minneapolis MN.
  • Gill, B., Knoll, A.H. & Johnston, D.T.  (2011).  Investigating geochemistry of the Wheeler Formation of Utah, USA: Insights into the redox environment of Burgess Shale-type fossil preservation.  Geological Society of America, 43(5): 53.
  • Grotzinger, J.P. & Milliken, R.E.  (2011, In Press).  The Sedimentary Rock Record of Mars: Distribution, Origins, and Global Stratigraphy.  In: Grotzinger, J.P.a.M. & R., E. (Eds.).  Sedimentary Geology of Mars.  SEPM Special Publication.
  • Hallmann, C., Kelly, A.E., Gupta, S.N. & Summons, R.E.  (2011).  Reconstructing Deep-Time Biology with Molecular Fossils.  In: Laflamme, M., Schiffbauer, J.D., Dornbos & , S.Q. (Eds.).  Quantifying the Evolution of Early Life, Topics in Geobiology.  Vol. 36.  Springer Netherlands.
  • Kaltenegger, L., Udry, S. & Pepe, F.A.  Habitable Planet around.  A&AL subm.
  • Knoll, A.H. & Fischer, W.W.  (2011).  Knoll, A.H. and W.W. Fischer.  In: J.P. Knoll, A.H.a.W.W.F. (Eds.).  Ocean Acidification.  Oxford University Press.
  • Knoll, A.H. & Konhauser, D.E.C.a.K.  (2011, In Press).  Essentials of Geobiology.  In: Knoll, A.H. & Konhauser, D.E.C.a.K. (Eds.).  Cambridge MA: Wiley-Blackwell.
  • Laflamme, M. & Casey, M.M.  Morphometrics in the study of Ediacaran fossil shapes.  In: Laflamme, M., Schiffbauer, J.D., Dornbos & Springer’s, S.Q. (Eds.).  Quantifying the Evolution of Early Life: Numerical and Technological Approaches to the Evaluation of Fossils and Ancient Ecosystems.  Vol. 36.
  • Laflamme, M., Schiffbauer, J.D. & Narbonne, G.M.  (In Press).  Deep-Water Microbially Induced Sedimentary Structures (MISS) in Deep Time: The Ediacaran Fossil Ivesheadia in Microbial Mats in Sandy Deposits (Archean Era to Today).  In: Noffke and Henry Chafetz, N.K. (Eds.).  SEPM Special Publication.
  • Pruss, S., Clemente, H. & Laflamme, M.  (Accepted).  Early (Series 2) Cambrian archaeocyathid reefs as a locus for skeletal carbonate production: New insights from the Forteau Formation, southern Labrador.  Lethaia.
  • Summons, R.E.  (2012).  The Great Oxidation Event [Book Chapter].  Science Year 2012.  Chicago: World Book Inc.
  • Winchell, C.J. & Jacobs, D.K.  (In Preparation).  Expression of the LIM homeobox genes apterous and lim1 during post-embryonic development in the nereidid polychaete Neanthes arenaceodentata.  Evolution & Development.
  • Yang, E.C., Boo, S.M., Bhattacharya, D., Saunders, G.W., Knoll, A.H., Fredericq, S. & Yoon, H.S.  (2011, Submitted).  Divergence time estimates and evolution of major lineages in the florideophyte red algae.  PLoS One.