Heather M. Stoll

Dept de Geologia Universidad de Oviedo

Arias de Velasco s/n 33005 Oviedo Asturias Spain

hstoll@geol.uniovi.es +34 985 10 2867 (phone)


Research Projects

Teaching and Outreach Resources



Research News

In Nature (August 29, 2013)

Bolton, C. and Stoll, H.M. (2013) Late Miocene threshold response of marine algae to carbon dioxide limitation.  Nature 500:558-562.

Coccolithophores are unique in that they use carbon for both photosynthesis and calcification.  We develop a new inverse model of carbon allocation in the cell, driven by the isotopic composition of carbon in the calcite and organic matter, and show that when carbon dioxide levels are low, coccolithophorids in culture reallocate HCO3- from photosynthesis to calcification.  This provides the first evidence that competition between photosynthesis and calcification is widespread and occurs in several different species. 

This adaptation arose in the latest Miocene in response to the crossing of a critical threshold in dissolved CO2 in the ocean, which we infer to result from  decreasing atmospheric CO2.  Such a decrease is consistent with widespread evidence for cooling over that time interval.

News and Views comment byPancost and Badger, and Reinfelder


Research Projects

Marine productivity and the carbon cycle

Algal evolution

Past hydrological changes recorded in stalagmites

Algal evolution ERC Project PACE

If current trends continue, over the next few centuries atmospheric CO2 from will likely to reach levels last seen tens of millions of years ago.    Evidence suggests that modern calcifying algae and diatoms employ a range of carbon acquisition strategies (such as active carbon concentrating mechanisms) according to their cell geometry and the pH and carbon speciation of the seawater in which they live.  However, we have observed that calcifying algae from 60 million years ago apparently had a single or less diverse array of carbon acquisition strategies.  The project will identify and calibrate novel geochemical fossil indicators for adaptation and evolution in carbon acquisition strategies in eukaryotic algae, and apply these indicators to establish the magnitude, rate, and timing of changes in carbon acquisition strategies by algae in response to past changes in the carbon cycle and atmospheric CO2 over the past 60 million years.  Funding source is ERC- EC VII Plan Marco.  See PACE project website for recent results.

Marine productivity and the carbon cycle

I have worked on developing new indicators for productivity variations from the chemistry of calcite coccoliths produced by marine coccolithophorid algae.  I have used laboratory cultures and sediment trap time series for verification, and applied these indicators to study past productivity variations in the Quaternary Arabian Sea and Bay of Bengal and over the Paleocene-Eocene Thermal Maximum.  As part of this work, we developed a new method for picking individual coccoliths with a micromanipulator, and mounting them for trace element analysis via ion probe (SIMS) in collaboration with Nobu Shimizu at Woods Hole Oceanographic Institute.  Funding sources U.S. NSF and Petroleum Research Fund.


Past Hydrological Changes Recorded in Stalagmites

We are working to reconstruct past changes in hydrological balance (P-E) and precipitation dynamics (moisture source) in NW Spain, from orbital timescales to multidecadal variations over the last few millennia.  This region is sensitive to NAO influence and potential orbital excitation of climate modes.  We are also working to ascertain if the frequency of extreme precipitation events leading to floods can be reconstructed from stalagmites.  Dripwater monitoring, with a device we designed, has been conducted in various caves since 2003 and synoptic scale rainwater isotope monitoring since 2006. This project is in collaboration with geomorphology group at Oviedo (Montse Jimenez, Maria Jose Dominguez), dating expertise at U. Minnesota (R. Larry Edwards, Hai Chang), and others (Ana Moreno, Steve Burns, Ricardo Trigo, Ana Mendez).  Principal funding is from Spanish Ministry of Science and Asturias government regional science ministry.

See the I-STAL download and information page for a model to attain quantitative interpretations of changes in dripwater flow rate using stalagmite trace element measurements.


Experience and Awards

PhD, Princeton University, 1998

Gretchen Bletchschmidt Award, GSA, 1996

NATO-NSF Postdoctoral Fellowship, 1998-2000

EGU Outstanding Young Scientist Award, 2006

DuPont Young Professor Award, 2008

ERC Starting Investigator Award, 2009

Teaching Experience:

Williams College: (tenure awarded): The Carbon Cycle, Climate Changes, Environmental Geology, Introduction to Environmental Science

Univ. of Oviedo: Masters courses in Climate Change, Marine Biogeochemical Cycles and Paleoceanography, Undergraduate course in Geochemistry

Supervision of PhD research

Co-supervision of PhD Mascha Dedert (Vrije Univ. Amsterdam, defended May 2012). The calcareous nannoplankton response to hyperthermals reconstructed from Late Paleocene and Early Eocene deep sea sediments.

Director of two current PhD students:

Luz Maria Mejia-Ramirez, Indicators of Algal Adaptation to CO2 in Diatom Geochemistry (University of Oviedo)

Saul Gonzalez-Lemos, Records of Past Floods in Cave Deposits (University of Oviedo)

Supervision of Masters theses

·         Gemma Pirla Casasayas, 2011, Study of the climate of Asturias in the penultimate glacial period using speleothems from the Vallina Cave, Porrua

·         Saul Gonzalez Lemos, 2012, Paleoflood reconstruction from caves in Asturias.

·         Luz Maria Mejia Ramirez, 2010, Paleoproductivity record in the Atlantic Sector of the Southern Ocean north of the subtropical front during the last glacial cycle.

·         Catarina Dinis Cavaleiro, 2011Paleo-productivity changes in the Mid Atlantic (IODP site U1313) during Marine Isotope Stages 10 nd 12 based on nannofossil Sr/Ca data.

·         Ursula Garcia-Carpintero Morell, 2011.  CO2 and Primary Production in the Ocean.



In review

Published Peer-Reviewed Articles(see also Researcher ID  G-9066-2012)

Bolton, C. and Stoll, H.M. (2013) Late Miocene threshold response of marine algae to carbon dioxide limitation.  Nature 500:558-562.

Isensee, K., Erez, J., and Stoll, H.M.Detection of a variable intracellular acid-labile carbon pool in Thalassiosira weissflogii (Heterokontophyta) and Emiliania huxleyi (Haptophyta) in response to changes in the seawater carbon system, Physiologia Plantarum, in press.

Mejía, L.M.*, Isensee, K., Méndez-Vicente, A.Pisonero, J. , Shimizu, N., Gonzalez, C., Monteleone, B., and Stoll, H.M..   , B content and Si quotas from cultured diatoms (Thalassiosira pseudonanaand Thalassiosira weissflogii): relationship to seawater pH and diatom carbon acquisition.  Geochimica et Cosmochimica Acta, in press.

Stoll, H.M., Moreno, A.,  Mendez-Vicente, A., Gonzalez-Lemos,S. Jimenez-Sanchez, M., Dominguez-Cuesta; M.J., Edwards, R. L. ,  Cheng,H. and  Wang, X. Growth rates of speleothems in NW Iberian Peninsula over the last two glacial cycles and relationship with climate.  Quaternary Research, 2013.

Bolton, C.T., Stoll, H.M., Mendez-Vicente, A., 2012. Vital effects in coccolith calcite: Cenozoic climate-pCO(2) drove the diversity of carbon acquisition strategies in coccolithophores? Paleoceanography 27.

Stoll, H., 2012. OCEAN SCIENCE Ancient burial at sea. Nature 488, 596-597.

Villa, E.; Stoll, H; Farias. P.; Adrados, L; Edwards, R. L; Cheng, H.Age and siginificance of the quaternary cemented deposits of the Duje Valley (Picos de Europa, Northern Spain).Quaternary Research, 2012.

Stoll, H.M.; Muller, W.; Prieto, M.I-STAL, a model for interpretation of Mg/Ca, Sr/Ca and Ba/Ca variations in speleothems and its forward and inverse application on seasonal to millennial scales.Geochemistry Geophysics Geosystems.13,2012.

Stoll, H. M., G. Langer, N. Shimizu and K. Kanamaru: B/Ca ratios in coccoliths and relationship to calcification vesicle pH and dissolved inorganic carbon, Geochimica et Cosmochimica Acta 80, 143, 2012.

S. Blanco-Ameijeiras, M. Lebrato, H. M. Stoll, M. D. Iglesias-Rodriguez, A. Méndez-Vicente, S. Sett, M. N. Müller, A. Oschlies, K. G. Schulz. Removal of organic magnesium in coccolithophore calcite. Geochimica et Cosmochimica Acta, Volume 89, 226-239, 2012.

Dedert, M.´12, Stoll, H.M., Kroon, D., Shimizu, N., Kanamaru, K., Ziveri, P., 2012. Productivity response of calcareous nannoplankton to Eocene Thermal Maximum 2 (ETM2). Climate of the Past 8, 977-993.

Fortes, F.J., Vadillo, I., Stoll, H., Jimenez-Sanchez, M., Moreno, A., Laserna, J.J., 2012. Spatial distribution of paleoclimatic proxies in stalagmite slabs using laser-induced breakdown spectroscopy. Journal of Analytical Atomic Spectrometry 27, 868-873.

Rudzka, D., McDermott, F., Baldini, L.M., Fleitmann, D., Moreno, A. and Stoll,H. A coupled 13C-radiocarbon investigation of cave and soil processes recorded by three European speleothems during the Late Glacial and early Holocene. Quaternary Science Reviews, 2011.

Stoll, H.M. Ion Partitioning and trace element proxies in foraminifera and coccoliths, in Prieto, M., and Stoll, H. Eds. Ion Partitioning in Ambient-Temperature Aqueous Systems. European Mineralogical Union, 2010.

Moreno, A., Stoll, H., Jimenez-Sanchez, M., Cacho, I., Valero-Garces, B., Ito, E., and Edwards, R.L. A speleothem record of glacial rapid climatic changes from Northern Iberian Peninsula, Global and Planetary Change, 2010.

Gibbs, S., Stoll, H.M., Bown, P., and Bralower, T. Surface water saturation state and carbonate production across the Paleocene-Eocene Thermal Maximum.  Earth and Planetary Science Letters, 2010.

Auliaherliaty, L.** Stoll, H.M., Ziveri, P. et al. Coccolith Sr/Ca ratios in Eastern Mediterranean: production vs. export processes.  Marine Micropaleontology 73, 196-206, 2009.

Stoll, H.M. and Shimizu, N. Micro-picking of nannofossils in preparation for analysis by secondary ion mass spectrometry.  Nature Protocols, 2009.

Moreno, A., Valero-Garces, B., Jimenez-Sanchez, M., Dominguez, M.J., Mata, P., Navas, A., Gonzalez-Samperiz, P., Stoll, H., Farias, P., Morellon, M., Corella, J., Rico, M. The last deglaciation in the Picos de Europa National Park (Cantabrian Mountains, Northern Spain).  Journal of Quaternary Science, 2009.

Langer, G., Nehrke, G., Thoms, S., Stoll, H.  Ba partitioning in coccoliths of Emiliania huxleyiGeochimica et Cosmochimica Acta, 2009.

Stoll, H.M., Shimizu, N., Ziveri, P., and Archer, D. Coccolithophore Productivity Response to Greenhouse Event of the Paleocene-Eocene Thermal Maximum, Earth and Planetary Science Letters,258, p. 192-206, 2007.

Stoll, H.M., Vance, D. and Arevalos, A.’05 Nd isotope records from Bay of Bengal constrain effect of Northern Hemisphere cooling on ITCZ movement. Earth and Planetary Science Letters 255, 213-228, 2007.

Stoll, H.M., Ziveri, P., Shimizu, N., Conte, M., and Theroux, S’05. Relationship between coccolith Sr/Ca ratios and coccolithophore production and export in the Arabian Sea and Sargasso Sea, Deep Sea Research II 54, p. 581-600. (Special Issue on Role of Marine Organic Carbon and Calcite Fluxes in Driving Global Climate Change, Past and Future), 2007.  

Ziveri, P., DeBernardi, B., Baumann, K., Stoll, H.M., and Mortyn, P.G. Sinking of coccolith carbonate and potential contribution to organic carbon ballasting in the deep ocean. Deep Sea Research II 54, p. 659-675. (Special Issue on Role of Marine Organic Carbon and Calcite Fluxes in Driving Global Climate Change, Past and Future), 2007.

Stoll, H.M., Arevalos, A.’05, Burke, A.’06, Ziveri, P., Mortyn, P.G., Shimizu, N. and Unger, D.  Seasonal Cycle of Coccolithophorid and Biogenic Carbonate Productivity in Bay of Bengal Sediment Traps.  Deep Sea Research II 54,  (Special Issue on Role of Marine Organic Carbon and Calcite Fluxes in Driving Global Climate Change, Past and Future), 2007. 

Stoll, H.M., Shimizu, N., Arevalos, A.’05,  Matell  N.’06, Banasiak,A.’08, and Zeren, S. ‘05Insights on Coccolith Chemistry from a New Ion Probe Method for Analysis of Individually Picked Coccoliths. Geochemistry Geophysics Geosystems, 8, Q06020, doi:10.1029/2006GC001546, 2007.

Stoll, H.M. Climate Change: The Arctic tells its story (News and Views).  Nature, 441, 579-581.

Stoll, H.M. Limited range of interspecific vital effects in coccolith stable isotopic records during the Paleocene-Eocene Thermal Maximum.  Paleoceanography, doi 10/1029PA2004001046, 2005

Stoll, H.M. Response to comment onCoccolith Sr/Ca records of productivity during the Paleocene-Eocene Thermal Maximum from the Weddell Sea”. Paleoceanography,  v.19 doi 10.1029/2003PA000971, 2004. 

Stoll, H.M. and Bains, S.Coccolith Sr/Ca records of productivity during the Paleocene-Eocene Thermal Maximum from the Weddell Sea Paleoceanography, v. 18 doi 10.1029/2002PA000875,  2003.

Ziveri, P*., Stoll, H.M*., Probert I. , Klaas, C., Geisen, M.,  Young J., and Ganssen, G. Stable Isotope Vital Effects in Coccolith Calcite. Earth and Planetary Science Letters 210, p. 137-149, 2003. (authors marked with asterisk contributed equally to this work as noted in the article)

Stoll, H.M., Ziveri, P., Geisen, M., Probert, I., and Young, J.R.  Potential and limitations of Sr/Ca ratios in coccolith carbonate: new perspectives from cultures and monospecific samples from sediments.  Phil. Trans. Roy. Soc. of Lond. A 360, 719-747, 2002.

Stoll, H.M., Rosenthal, Y., and Falkowski, P.   "Climate proxies from Sr/Ca of coccolith calcite: calibrations from continuous culture of Emiliania huxleyi."  Geochimica et Cosmochimica Acta, 66, 927-936, 2002. 

Stoll, H.M. and Ziveri, P. Separation of mono-specific and restricted coccolith assemblages from sediments using differential settling velocity Marine Micropaleontology, 46, 209-221, 2002. 

Stoll, H.M, Ruiz-Encinar, J., Garcia-Alonso, J.I., Rosenthal, Y.Klaas, C., and Probert, I.  A first look at paleotemperature prospects from Mg in coccolith carbonate: cleaning techniques and culture measurements. Geochemistry, Geophysics, Geosystems, 2001.

Stoll, H.M, Klaas, C., Probert, I. P.,Ruiz-Encinar, J., Garcia-Alonso, J.I.Calcification rate and temperature effects on Sr partitioning in coccoliths of multiple species of coccolithophorids in culture.  Global and Planetary Change 34, 153-171, 2002.

Stoll, H.M. and Schrag, D.P.  Sr/Ca variations in Cretaceous carbonates: relation to productivity and sea level changes.  Palaeogeography, Palaeoclimatology, Palaeoecology 168, 311-336, 2001.

Stoll, H. M., and D.P. Schrag, Coccolith Sr/Ca as a new indicator of coccolithophorid calcification and growth rate.   Geochemistry Geophysics Geosystems, 1, 1-24, 2000.

Stoll, H. M.  and D. P. Schrag. High resolution stable isotope records from the Upper Cretaceous of Italy and Spain: Glacial episodes in a greenhouse planet? GSA Bulletin, 112, 308-319, 2000.

Stoll, H. M., D. P. Schrag, and S. C. Clemens, Are seawater Sr/Ca variations preserved in Quaternary foraminifera? Geochimica et Cosmochimica Acta, 63, 3535-3547, 1999.    

Stoll, H. M.  and D. P. Schrag,  Effect of Quaternary sea level cycles on the Sr budget of the ocean.  Geochimica et Cosmochimica Acta, 62, 1107-1118, 1998.

Karabinos, P., S.D. Samson, J.C. Hepburn, and H. M. Stoll. Taconian orogeny in the New England Appalachians: Collision between Laurentia and the Shelburne Falls Arc. Geology, 26, 215-218, 1998.

Stoll, H. M. and D. P. Schrag,  Evidence for Glacial Control of Rapid Sea Level Changes in the Early Cretaceous.  Science, 272, 1771-1774, 1996.

Books and Book Chapters

Prieto, M., and Stoll, H. Eds. Ion Partitioning in Ambient-Temperature Aqueous Systems. European Mineralogical Union, 2010.

Stoll, H.M. Ion Partitioning and trace element proxies in foraminifera and coccoliths, in Prieto, M., and Stoll, H. Eds. Ion Partitioning in Ambient-Temperature Aqueous Systems. European Mineralogical Union, 2010.

Stoll, H.M. and Ziveri, P.  Coccolithophore-based geochemical proxies in Thierstein, H. and Young, J. Eds. Coccolithophores: From Molecular Processes to Global Impact. Springer Verlag, 2004.

Other education publications

Karabinos, P., H. M. Stoll, and W. T. Fox.  Attracting Students to Science through Field Exercises in Introductory Geology Courses. Journal of Geological Education , 40, 302-305, 1992.

In review

Mendez-Vicente, Ana, Hernandez Sanchez, Maria Teresa, Gonzalez Lemos, Saul, Mejia-Ramirez Luz Maria, Isensee, Kirsten, Stoll, Heather M.  NanoEA-IRMS determination of δ13C of diatom frustule-bound organic matter, and its relationship with δ13C of total cellular organic matter and total lipid fraction.  Paleoceanography, in review.

Diaz, Silvia, Ruiz Encinar, Jorge, Isensee, Kirsten, and Stoll, Heather.  Determination of B/Ca ratios in very low B carbonates with 11B/46Ca measurements on triple quadrupole ICP-MS.  Journal of Analytical Atomic Spectroscopy, in prep.

Dedert, M.*, Stoll, H.M., Kars, S., Young, J.R., Shimizu, N., Kroon, D., Lourens, L., and Ziveri, P.,.  Temporally variable diagenetic overgrowth on deep-sea nannofossil carbonates across Palaeogene hyperthermals and implications for isotopic analyses. Marine Micropaleontolog, in review.

Martinez-Pillado, V., Aranburu, A., Arsuaga, J.L., Ruiz-Zapata, B., Gil-Garcia, M.J., Stoll, H.M., Yusta, I., Iriarte, E., and Carretero, J.M. Upper Pleistocene and Holocene palaeoenvironmental records in Cueva Mayor karst (Atapuerca, Spain) from different proxies: Speleothem crystal fabrics, Palynology and Archaeology, Journal of Quaternary Science, submitted and under review.