Dr. Luz Maria Mejia Ramirez

Research interest

Reliable predictions of the Earth System’s response to different climate forcing highly depends on the accuracy with which we are able to reconstruct trends and absolute values of temperature and CO₂. None of the existing proxies are flawless, and our incomplete understanding of the their controlling mechanisms, many of which are physiologically and/or ecologically-controlled, is likely to introduce significant uncertainties in absolute values and trends of reconstructions. My main research interest is in better understanding these mechanisms, and the development of new proxies, so as to improve reconstructions of past climate. Only when we fully understand the paleo-instruments we are using, will we be able to ascertain that our reconstructions are accurate enough for modelling studies to apply for future climate predictions.

Qualifications

Publications

Zhang, H., C. Liu, L.M. Mejía, H. Stoll (2021), Accelerate coccolith size separation via repeated centrifugation. Biogeosciences 18, 1909-1916, doi: doi.org/10.5194/bg-18-1909-2021.

Zhang, H., S. Blanco-Ameijeiras, B.M. Hopkinson, S.M. Bernasconi, L.M. Mejía, C. Liu, H. Stoll (2021), An isotope label method for empirical detection of carbonic anhydrase in the calcification pathway of the coccolithophores Emilinia huxleyi, Geochimica et Cosmochimica Acta 292, 79-93, doi: doi.org/10.1016/j.gca.2020.09.008.

Stoll, H.M., J. Guitian, I. Hernandez-Almeida, L.M. Mejía, S. Phelps, P. Polissar, Y. Rosenthal, H. Zhang, P. Ziveri (2019), Upregulation of phytoplankton carbon concentrating mechanisms during low CO2 glacial periods and implications for the phytoplankton pCO2 proxy. Quaternary Science Reviews 208, 1-20, doi: doi.org/10.1016/j.quascirev.2019.01.012.

Mejía, L.M., B. Revels (2018). Climate change effects on Colombian biodiversity (chapter 11), in Colombia: Doctoral excursion. Earth Sciences Department, ETH Zürich, 43-47, doi: 10.3929/ethz-b-000327761.

Mejía, L.M., A. Paytan, A. Eisenhauer, F. Böhm, A. Kolevica, C. Bolton, A. Méndez-Vicente, L. Abrevaya, K. Isensee, and H.M. Stoll (2018), Controls over d^44/40Ca and Sr/Ca variations in coccoliths: new perspectives from laboratory cultures and cellular models. EPSL 481, 48-60, doi: doi.org/10.1016/j.epsl.2017.10.013.

Shephard, G.E., S. Wiers, E. Bazhenova, L.F. Pérez, L.M. Mejía, C. Johansson, M. Jakobsson, and M. O’Regan (2018), A North Pole thermal anomaly? Evidence from new and existing heat flow measurements from the central Arctic Ocean. J. of Geodynamics, Arctic Special Issue 118, 166-181, doi: 10.1016/j.jog.2018.01.017. 

Mejía, L.M., A. Méndez-Vicente, L. Abrevaya, K. Lawrence, C. Ladlow, C. Bolton, I. Cacho, and H.M. Stoll (2017), A diatom record of CO₂ decline since the late Miocene. EPSL 439, 18-33, doi: doi.org/10.1016/j.epsl.2017.08.034. 

Mejía, L.M., P. Ziveri, M. Cagnetti, C. Bolton, R. Zahn, G. Marino, G. Martínez-Méndez, and H.M. Stoll (2014), Effects of midlatitude westerlies on the paleoproductivity at the Agulhas Bank slope during the penultimate glacial cycle: Evidence from coccolith Sr/Ca ratios, Paleoceanography 29 (7), 697-714, doi:10.1002/2013PA002589. 

Mejía, L.M., K. Isensee, A. Méndez-Vicente, J. Pisonero, N. Shimizu, C. González, B. Monteleone, and H.M. Stoll (2013), B content and Si/C ratios from cultured diatoms (Thalassiosira pseudonana and Thalassiosira weissflogii): Relationship to seawater pH and diatom carbon acquisition, Geochimica et Cosmochimica Acta 123, 322-337, doi: 10.1016/j.gca.2013.06.011.