Peleoclimate and Geobiology Research Group

Publications

FOR ELECTRONIC REPRINT REQUESTS, PLEASE SEND AN E-MAIL TO jochen.halfar@utoronto.ca

* Denotes student or postdoc of Halfar group

Williams, B., *Chan, P.,Halfar, J., K. Hargan, Adey, W. (accepted) Arctic crustose coralline alga resilient to environmental change, Limnology and Oceanography

Rasher, D.B., Steneck, R.S.,Halfar, J., Kroeker, K.J., Ries, J.B., Chan, P.T.W., Fietzke, J., Kamenos, N.A., Konar, B.H., Lefcheck, J.S., Norley, C.J., Weitzman, B.P., and Westfield, I.T., Estes, J.A., (2020), Keystone predators govern the pathway and pace of climate impacts in a subarctic marine ecosystem, Science, 369, 1351-1354

*Chan, P.,Halfar, J., Lebednik P.A., Norley C.J.D., Holdsworth D.W. (2020) Recent density decline in wild-collected subarctic crustose coralline algae reveals climate change signature, Geology,v. 48, p. 226 - 230, https://doi.org/10.1130/G46804.1

*Rahman, A.,Halfar, J.,Adey, W.H., Nash, M., Paulo, C., Dittrich, M. (2019) The role of chitin-rich skeletal organic matrix on the crystallization of calcium carbonate in the crustose coralline alga Leptophytum foecundum, Nature Scientific Reports, v. 9, 11869, doi.org/10.1038/s41598-019-47785-2

Hetzinger, S.,Halfar, J.,Zajacz, Z., Wisshak, M. (2019) Early start of 20th century Arctic sea ice decline recorded in Svalbard coralline algae, Geology, 47 (10): 963-967, 10.1130/G46507.1

Moffa-Sánchez, P., Moreno-Chamarro, E., Reynolds, D.J., Ortega, P., Cunningham, L., Swingedouw, D., Amrhein, D.E., Halfar, J., Jonkers, L., Jungclaus, J.H., Perner, K., Wanamaker, A., and Yeager, S. (2019) Variability in the northern North Atlantic and Arctic oceans across the last two millennia: A review, Palaeoceanography, Paleoclimatology, v. 34, 1399-1436, 10.1029/2018PA003508.

*Humphreys, A.F.,Halfar, J., Ingle, J.C., Reymond, C.E., Westphal, H.; Riegl, B. (2019) Shallow water benthic foraminifera of the Galapagos Archipelago: Ecologically sensitive carbonate producers in an atypical tropical oceanographic setting, Journal of Foraminiferal Researchv. 49, no. 1, p. 48-65

*Williams, S., Adey, W., Halfar, J., Kronz, A., Gagnon, P., Belanger, D., Nash, M. (2018) Effects of light and temperature on Mg uptake, growth, and calcification in the proxy climate archive Clathromorphum compactum, Biogeosciences15, 5745-5759

*Humphreys, A.F., Halfar, J., Ingle, J.C., Manzello, D., Reymond, C.E., Westphal, H.; Riegl, B. (2018) Seawater temperature, pH, and nutrients influence character, distribution, and low abundance of shallow water benthic foraminifera in the Galápagos, PLoS ONE13(9): e0202746

*Williams, S., Halfar, J., Zack, T., Hetzinger, S., Blicher, M., Juul-Pedersen, T., Kronz, A., Noël, B., Van den Broeke, M., Van de Berg, W. (2018) Coralline algae archive Fjord surface water temperatures in Southwest Greenland, Journal of Geophysical Research - Biogeosciences, 123, 8, 10p. 10.1029/2018JG004385

Light, T., Williams, B.,Halfar, J.,*Hou, A., Zajacz, Z., Tsay, S., Adey, W. (2018) Advancing Mg/Ca analysis of coralline algae as a climate proxy by assessing LA-ICP-OES sampling and coupled Mg/Ca - ?18O analysis, Geochemistry, Geophysics, Geosystems10.1029/2018GC007504,

Anhaeuser, T., *Hook, B.,Halfar, J.,Greule, M., F., Keppler, F. (2018) Early Eocene cold period and polar amplification - Insights from ?²H values of lignin methoxyl groups of mummified wood, Palaeogeography, Palaeoclimatology, Palaeoecology, v. 505, p. 326-336,

*Hou, A., Halfar, J.,Adey, W., Wortmann, U., Zajaczc, Z., Tsayc, S., Williams, B., Chan, P. (2018) Long-lived coralline alga records multidecadal variability in Labrador Sea carbon isotopes, Chemical Geology, https://doi.org/10.1016/j.chemgeo.2018.02.026, Impact Factor: 3.3

*Williams, S., Halfar, J.,Zack, T., Hetzinger, S., Blicher, M., Juul-Pedersen, T. (2018) Comparison of climate signals obtained from encrusting and free-living coralline algae. Chemical Geology, 476, p. 418-428, https://doi.org/10.1016/j.chemgeo.2017.11.03, Impact Factor: 3.3

Hetzinger, S., Halfar, J., Kronz, A., Simon, K., Adey, W., Steneck, R.S. (2018) Reproducibility of Clathromorphum compactum coralline algal Mg/Ca ratios and comparison to high-resolution sea surface temperature data, Geochimica et Cosmochimica Acta, v. 220, 96-109, https://doi.org/10.1016/j.gca.2017.09.044 Impact Factor: 4.3

*Chan, P.,Halfar, J., Norley, C., Pollmann, S., Adey, W., Holdsworth, D. (2017) Micro-computed tomography: Applications for high-resolution skeletal density and calcification rate determinations. An example using annually-resolved crustose coralline algae, Geochemistry, Geophysics, Geosystems, 18, doi:10.1002/2017GC006966. Impact Factor: 3.2.

Sletten, H.R., Gillikin D.,Halfar, J.,Andrus, F.C., Guzman, H., (2017) Skeletal growth controls on Mg/Ca and P/Ca ratios in tropical Eastern Pacific rhodoliths (coralline red algae),Chemical Geology, 465, p. 1-10, doi: 10.1016/j.chemgeo.2017.05.010

*Chan, P., Halfar, J., Adey, W., Hetzinger, S., Zack, T., G.W.K. Moore, U.G. Wortmann, B. Williams, A. Hou (2017) Multicentennial record of North Atlantic primary productivity and sea-ice variability archived in coralline algal Ba/Ca, Nature Communications, 10.1038/NCOMMS15543

*Williams, B., Halfar, J., DeLong, K.L., Smith, E., Steneck, R.S., Lebednik, P., Jacob, D., Fietzke, J., Moore, G.W.K. (2017) North Pacific 20th century decadal-scale variability is unique for the past 350 years, Geophysical Research Letters,10.1002/2017GL073138

Moore, G.W.K., Halfar, J., *Majeed, H., Adey, W., Kronz, A. (2017) Amplification of the Atlantic Multidecadal Oscillation associated with the onset of the industrial-era warming, Scientific Reports, 7:40861, DOI: 10.1038/srep40861

Sletten, H.R., Andrus, F.T., Guzman, H., Halfar, J. (2016) Re-evaluation of using rhodolith growth patterns for paleoenvironmental reconstruction: An example from the Gulf of Panama. Palaeogeography, Palaeoclimatology, Palaeoecology, http://dx.doi.org/10.1016/j.palaeo.2016.10.03851

Ng, J., Williams, B., Thompson, D., Mayne, C., Halfar, J.., Edinger, E., Johnson, K. (2016) Assessing multi-site ?18O-climate calibrations of the coralline alga Clathromorphum across the high-latitude Northern Hemisphere, Geochimica et Cosmochimica Acta, v. 194, 279-290, http://dx.doi.org/10.1016/j.gca.2016.08.023

*Humphreys, A.F., Halfar, J., Rivera, F., Manzello, D., Reymond, C.E., Westphal, H., Riegl, B. (2016) Variable ENSO influence on biofacies dynamics of Eastern Pacific shallow water carbonate systems, Geology, doi:10.1130/G37745

Joergensbye, H. I. O., Halfar, J. (2016) First overview of coralline red algal crusts and rhodolith beds (Corallinales, Rhodophyta) and their ecological importance in Greenland, Polar Biology, 10.1007/s00300-016-1975-1

Reymond, C.E., Zihrul, K.-S., Halfar, J., Riegl , B., *Humphreys, A., Westphal, H. (2016) Heterozoan carbonates from the equatorial rocky reefs of the Galapagos Archipelago, Sedimentology DOI: 10.1111/sed.12244

Mallela, J., Hetzinger, S., Halfar, J. (2015) Thermal stress markers in Colpophyllia natans provide an archive of site-specific bleaching event, Coral Reefs, DOI 10.1007/s00338-015-1350-7.

*Hook, B.A., Halfar, J., Gedalof, Z., Bollmann, J., *Rahman, Md.A., Reyes, J., Schulze, D. (2015) Extraction of alpha-cellulose from mummified wood for stable isotopic analysis, Chemical Geology, v. 405, 19-27

*Bougeois, L., *Williams, B., Halfar, J., Konar, B., Adey, W., Kronz, A., Wortmann, U. (2015) Does the coralline alga Leptophytum foecundum (Kjellman) capture paleoenvironmental variability in the Arctic Ocean? Arctic, Antarctic, and Alpine Research, 47, 2, 167-179, DOI: http://dx.doi.org/10.1657/AAAR0014-061

Adey, W., Halfar, J., *Humphreys, A., Suskiewicz, T., Belanger, D., Gagnon, P., Fox, M. (2015) Subarctic rhodolith beds promote longevity of crustose coralline algal buildups and their climate archiving potential, Palaios, 30, 281-293, DOI: http://dx.doi.org/10.2110/palo.2014.075

Fietzke, J., Ragazzola, F., Halfar, J., Dietze, H., Foster, L., Hansteen, T., Eisenhauer, A., Steneck, R.S. (2015) Boron isotope images reveal seasonal cycle and long-term trend in sea water pH, Proceedings National Academy of Sciences, www.pnas.org/cgi/doi/10.1073/pnas.1419216112

* Hook, B.A., Halfar, J., Gedalof, Z., Bollmann, J., and Schulze, D. (2015) Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic, v. 12, 5899 - 5914, Biogeosciences doi:10.5194/bg-12-5899-2015

*Rahman, A., Halfar, J. (2014) First evidence of chitin in calcified coralline algae: new insights into the algal calcification process, Scientific Reports (Nature), 4 : 6162 | DOI: 10.1038/srep06162

*Williams B.,Halfar, J., DeLong, K.L., *Hetzinger, S., Steneck, R.S., and Jacob D.E., (2014) Multi-specimen and multi-site calibration of Aleutian coralline algal Mg/Ca to sea surface temperature, http://dx.doi.org/10.1016/j.gca.2014.04.006 Geochimica et Cosmochimica Acta

Halfar, J., Adey, W.H., Kronz, A., *Hetzinger, S., Edinger, E., Fitzhugh, W. (2013) Arctic sea-ice decline archived by multicentury annual-resolution record from crustose coralline algal proxy, Proceedings National Academy of Sciences, www.pnas.org/cgi/doi/10.1073/pnas.1313775110

Highlighted in Nature: Climate sciences: Crusty alga uncovers sea-ice loss. (2013) 503(7477): 440

Adey, W.H, Halfar, J., *Williams, B. (2013) The coralline genus Clathromorphum Foslie emend. Adey: Biological, physiological, and ecological factors controlling carbonate production in an Arctic-Subarctic climate archive. Smithsonian Contributions to the Marine Sciences (Smithsonian Institution Scholarly Press, Washington, DC), vol 40, 1-48. DOWNLOAD ARTICLE HERE

*Hook, B.A., Halfar, J., Gedalof, Z., Bollmann, J., 2013, Controlled breaking of mummified wood for use in paleoenvironmental analysis, Tree-Ring Research, vol 69 (2), 87-92.(INCLUDING INSIDE COVER)

Halfar, J., Riegl, B., 2013, From coral framework to rhodolith bed: sedimentary footprint of the 1982/83 ENSO in the Galápagos, Coral Reefs, vol 32, 985, DOI 10.1007/s00338-013-1058-5.

*Hetzinger S., Halfar J., Zack T., Mecking J., Kunz, B., Jacob D., Adey, W.H., 2013, Coralline algal Barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability , Scientific Reports (Nature), 3, 1761, doi: 10.1038/srep01761.

*Rahman, M.A., Halfar, J., Shinjo, R. 2013, X-Ray Diffraction as a promising tool to characterize soft coral skeletons, Advances in Materials Physics and Chemistry, 2013, 3, 120-125, doi:10.4236/ampc.2013.31A015

*Hetzinger, S., Halfar J., Mecking, J. V., Keenlyside N. S., Kronz A., Steneck R. S., Adey W. H., Lebednik, P. A., 2012, First proxy evidence linking decadal North Pacific and Atlantic climate, Climate Dynamics, 39 (6), 1447-1455.

Halfar, J., *Eisele, M., Riegl, B., *Hetzinger, S., Godinez-Orta, L., 2012, Modern rhodolith-dominated carbonates at Punta Chivato, Mexico. Geodiversitas. 34 (1): 99-113. http://dx.doi.org/10.5252/g2012n1a6.

Halfar, J., *Williams, B, *Hetzinger, S., Steneck, R.S., Lebednik, P., *Winsborough, C., *Omar, A., *Chan, P., Wanamaker, A., 2011, 225 years of Bering Sea climate and ecosystem dynamics archived by coralline algae, Geology, v. 39, 6, 579-582, doi:10.1130/G31996

*Chan, P., Halfar, J., *Hetzinger, S., *Williams, B., Steneck, R.S., Zack, T., Kunz, B., Jacob, D., 2011, Freshening of the Alaska Coastal Current recorded by coralline algal Ba/Ca ratios, Journal of Geophysical Research – Biogeosciences 116, G01032, doi:10.1029/2010JG001548

Wanamaker, A.D. Jr., *Hetzinger, S., Halfar, J., 2011, Reconstructing mid- to high-latitude marine climate and ocean variability using bivalves, coralline algae, and marine sediments from the Northern Hemisphere, Palaeogeography, Palaeoclimatology, Palaeoecology, 302, 1-9, doi:10.1016/j.palaeo.2010.12.024

Halfar, J., *Hetzinger, S., Zack T., Adey, W., *Gamboa, G., Kunz, B., W*illiams, B., Jacob D., 2011, Coralline red algal growth-increment widths archive North Atlantic climate variability. Palaeogeography, Palaeoclimatology, Palaeoecology, 302, 71-80, doi:10.1016/j.palaeo.2010.04.009

*Hetzinger, S., Halfar, J., Zack, T., Jacob, D., Kunz, B., *Gamboa, G., Kronz, A., Adey, W., Lebednik, P., Steneck, R., 2011. High-resolution analysis of trace elements from the North Atlantic and North Pacific in encrusting coralline algae by laser ablation ICP-MS. Palaeogeography, Palaeoclimatology, Palaeoecology, 302, 81-94 doi:10.1016/j.palaeo.2010.06.004

*Williams, B., Halfar, J, Steneck, R.S., Wortmann, U.G., *Hetzinger, S., Adey, W., Lebednik, P., Joachimski, M., 2011, Twentieth century d13C variability in surface water dissolved inorganic carbon recorded by coralline algae in the northern North Pacific Ocean and the Bering Sea, Biogeosciences, 8, 165-174. doi:10.5194/bg-8-165-2011

*Gamboa, G., Halfar, J., *Hetzinger, S., Adey, W., Zack, T., Kunz, B., Jacob D.E., 2010, Mg/Ca ratios in coralline algae as proxies for NW Atlantic temperature variations. Journal of Geophysical Research – Oceans, 115, C12044, doi:10.1029/2010JC006262

*Hetzinger, S., Pfeiffer, M., Dullo, W.C., Garbe-Schönberg, D., Halfar, J., 2010, Rapid 20th century warming in the Caribbean and impact of remote forcing on climate in the northern tropical Atlantic as recorded in a Guadeloupe coral. Palaeogeography, Palaeoclimatology, Palaeoecology, 296, 1-2, 111-124

Westphal, H., Halfar, J., Freiwald, A., 2010, Non-coralgal carbonates in subtropical to tropical settings in the present and in the past. International Journal of Earth Sciences, 99, S153-S169

*Hetzinger, S., Halfar, J., Kronz, A., Steneck, R., Adey, W., Lebednik, P., Schöne, B.R., 2009, High-resolution Mg/Ca ratios in a coralline red algae as a proxy for Bering Sea temperature variations. Palaios, v. 24, 406-412.

Halfar, J., Steneck, R., Joachimski, M., Kronz, A., Wanamaker, A.D. Jr., 2008, Coralline red algae as high-resolution climate recorders, Geology, v. 36, 6, 463-466

Halfar, J., Fujita, R., 2007, Danger of deep-sea mining - Plans for deep-sea mining could pose a serious threat to marine ecosystems, Science, 316, 987.

Halfar, J., Steneck, R., Schöne, B., Moore, G.W.K., Joachimski, M., Kronz, A., Fietzke, J., Estes, J., 2007, Coralline alga reveals first marine record of subarctic North Pacific climate change, Geophysical Research Letters,34, L07702, doi:10.1029/2006GL028811. (Selected as EDITOR’s HIGHLIGHT).

Fuentes-Yaco, C., Valdez-Holguín, J.E., Devred, E., Platt T., Sathyendranath, S., Halfar, J., Godinez Orta, L., Borges, J.M., 2007, Teledección del impacto del Huracán Ignacio (2003) en el Pacífico Tropical Oriental. In: B. Hernández de la Torre, G. Gaxiola Castro (Eds.): Carbono en Ecosistemas Acuáticos de México, Instituto Nacional de Ecología and CICESE, México.

Riegl, B., Halfar, J., Purkis, S.J., Godinez-Orta, L., 2007, Sedimentary facies of the eastern Pacific’s northernmost reef-like setting (Cabo Pulmo, Mexico): geophysical and remote-sensing based mapping, Marine Geology, v. 236, 61-77.

Fuentes-Yaco, C., Valdez-Holguín, J.E., Devred, E., Platt T., Sathyendranath, S., Halfar, J., Godinez Orta, L., Borges, J.M., 2006, Biological impact of Hurricane Ignacio (2003) in the Eastern Pacific Ocean as observed through MODIS data. In: Robert J. Frouin, V.K. Agarwa, H. Kawamura, S. Nayak, D. Pan (Eds.): Remote Sensing of the Marine Environment. Proceedings of International Society for Optical Engineering, v. 6406, 640612, 10 p.

*Hetzinger, S., Halfar, J., Riegl, B., Godinez-Orta, L., 2006, Sedimentology and acoustic mapping of modern rhodolith beds on a non-tropical carbonate shelf (Gulf of California, Mexico). Journal of Sedimentary Research, v. 76, 670-682.

Halfar, J., Godinez-Orta, L., Mutti, M., Valdez-Holguin, J.E., Borges, J.M., 2006, Carbonates calibrated against oceanographic parameters along a latitudinal transect in the Gulf of California, Mexico. Sedimentology, v. 53, 297-320.

Halfar, J., *Strasser, M., Riegl, B., Godinez-Orta, L., 2006, Oceanography, acoustic mapping and sedimentology of a bryomol carbonate factory in the northern Gulf of California, Mexico. In: Pedley, P.M, Carannante, G. (Eds.): Cool-Water Carbonates: Depositional Systems and Palaeoenvironmental Controls. Geological Society of London Special Publications, v. 255, 197-215.

Halfar, J., Godinez-Orta, L., Riegl, B., Valdez-Holguin, J.E., Borges, J.M., 2005, Living on the edge: High-latitude Porites carbonate production under warm temperate eutrophic conditions. Coral Reefs, v. 24, p. 582-592.

Halfar, J., Mutti, M., 2005, Global dominance of coralline red-algal facies: A response to Miocene oceanographic events. Geology, v. 33, no. 6, p. 481-484.

Halfar, J., Godinez-Orta, L., Mutti, M., Valdez-Holguin, J, Borges, J., 2004, Nutrient and temperature controls on modern carbonate production: an example from the Gulf of California, Mexico. Geology, v. 32, no. 3, p. 213-216.

Halfar, J., Ingle, J.C., Godinez-Orta. L., 2004, Modern heterozoan mixed carbonate-siliciclastic sediments and environments of the southwestern Gulf of California, Mexico. Sedimentary Geology, v. 165, p. 93-115.

Halfar, J., Ingle, J.C., 2003, Modern warm-temperate and subtropical shallow water benthic foraminifera of the southern Gulf of California, Mexico. Journal of Foraminiferal Research, v. 33, no. 4, p. 309-329.

Halfar, J., Fujita, R. M., 2002, Precautionary management of deep-sea mining. Marine Policy, v. 26, 2, p. 103-106.

Halfar, J., Godinez-Orta, L., Goodfriend, G.A., Mucciarone, D.A, Ingle, J. C., Holden, P., 2001, Holocene-Pleistocene carbonate sedimentation and tectonic history of the La Paz area, Baja California Sur, Mexico. Sedimentary Geology, v. 144, 1-2, p. 149-177

Halfar, J., Zack, T., Kronz, A., Zachos, J., 2000, Geochemical signals of rhodoliths (coralline red algae)- a new biogenic archive. Journal of Geophysical Research, v. 105 , No. C9 , p. 22,107-22,116

Halfar, J, Godinez-Orta, L, Ingle, J. C., 2000, Microfacies analysis of Recent carbonate environments in the southern Gulf of California, Mexico- a model for warm-temperate to subtropical carbonate formation. Palaios, v. 15, p. 323-342.

Goodfriend, G.A., Halfar, J., Godinez-Orta, L., 2000, Chronostratigraphy of sediments in the southern Gulf of California, based on amino acid racemization analysis of mollusks and rhodoliths. In: Goodfriend, G.A., Collins, M.J., Fogel, M.L., Macko, S A., and Wehmiller, J.F. (Eds.), Perspectives in Amino Acid and Protein Geochemistry, Oxford Univ. Press, New York, pp. 320-330.

Halfar, J., Riegel, W., Walther, H., 1998, Facies architecture and sedimentology of fluvial deposits: A Paleogene example from the Weisselster Basin, Germany. Sedimentology, v. 3, p.1-17.

Halfar, J. and Riegel, W., 1995, Faziesarchitektur and Sedimentologie eines paläogenen fluviatilen Systems im Tagebau Schleenhain, Leipzig; Abhandlungen des Staatlichen Museums für Mineralogie und Geologie zu Dresden, v. 41, p. 53-72.

Editor:

Halfar, J.; Nava-Sanchez, E. (guest editors of special issue), 2001, Sedimentation and Tectonics Along a Rift Basin Margin: The Gulf of California. Sedimentary Geology, v. 144, 1-2.

Hetzinger, S., Wanamaker, A., Halfar, J. (guest editors of special issue), 2011, Reconstructing mid- to high-latitude climate and ocean variability from high-resolution biogenic archives. Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 302, issues 1–2

Others:

M. Wisshak, A. Bartholomä, L. Beuck, J. Büscher, A. Form, A. Freiwald, J. Halfar, S., Hetzinger, B. van Heugten, K. Hissmann, P. Holler, N. Meyer, H. Neumann, J. Raddatz, A. Rüggeberg, S. Teichert, A. Wehrmann (2016) Habitat characteristics and carbonate cycling of macrophyte-supported polar carbonate factories (Svalbard) MARIA S. MERIAN-Reports, Cruise No. MSM55, June 11 – June 29, 2016, Reykjavik (Iceland) – Longyearbyen (Svalbard), Deutsche Forschungsgemeinschaft

Halfar, J., Adey, W.H., Kronz, A., Hetzinger, S., Edinger, E., Fitzhugh, W. (2014) Arctic sea-ice decline archived by multicentury annual-resolution record from crustose coralline algal proxy, ICE Bulletin, International Glaciological Society, V. 154, p. 22

Williams, B., Halfar, J., and Adey, W (2011) High latitude coralline algae record North Atlantic Ocean variability, Canadian Ocean Science Newsletter, 56:1-2.

Halfar, J., Fujita, R., 2000, Mining on the continental shelf- a poorly regulated environmental issue, Internal Report, Environmental Defense, Oakland, USA, 17p.

Halfar, J., Fujita, R., 2000. The Current Status of Deep-Sea Mining and its Environmental Consequences, Internal Report, Environmental Defense, Oakland, USA, 19p.

Conference Contributions:

Chan, P.T.W., Halfar, J., Sigman, D., Zajacz, Z., Schöne, B.R., Jansen, E. (2020) Variability in Primary Productivity associated with Arctic sea-ice melt in Crustose Coralline Algae, Goldschmidt Meeting, Honolulu Hawaii, 21-26 June, 2020 (online delivery)

Hetzinger, S., Halfar, J. Zajacz, Z., Möller, M., Wisshak, M. (2020) Late 20th century increase in northern Svalbard glacier-derived runoff tracked by coralline algal Ba/Ca ratios EGU Vienna, May 3 -8, 2020 (online delivery)

Rasher, D.B., Steneck, R.S., Halfar, J., Kroeker, K.J., Ries, J.B., Chan, P.T.W., Fietzke, J., Kamenos, N.A., Konar, B.H., Lefcheck, J.S., Norley, C.J., Weitzman, B.P., and Westfield, I.T., Estes, J.A. (2020) Keystone predators govern the pathway and pace of climate impacts on kelp forests of the Aleutian archipelago, Gordon Research Conference, Jan 26-31, Ventura, California, United States

Rasmusson, L.M., Halfar, J., Hall-Spencer, J.M., Linderholm, H.W., (2020) Exploring the potential of Arctic coralline algae as a paleosalinity proxy. Bristish Phycological Society, Plymouth, Jan 6-9.

Rahman, A., Halfar, J. (2019) Collagen of Extracellular Matrix from Marine Calcifiers and Its Medical Applications, The Japan-US Science Forum, Harvard University, Boston Nov. 2nd 2019

Halfar, J., *Leclerc, N., *Van der Linden, A., Moore, G.W.K. , *Shana, S., Tsay, S., Zajacz, Z. (2019) Record of Arctic Oscillation driven sea ice variability in Lancaster Sound, Canadian Arctic, using the long-lived coralline alga Clathromorphum compactum, GSA Annual Meeting, Phoenix, USA, September 2019

*Leclerc, N., Zulian, M., Halfar, J., Hetzinger, S. (2019) Intra- and inter-observer reliability of coralline red alga Clathromorphum compactum as a sea ice cover proxy, GSA Annual Meeting, Phoenix, USA, September 2019

*Zulian, M., Fietzke, J., Halfar, J., Schöne, B.R. (2019) Seasonality in marine archives: implications of high-resolution data for assessing ecosystem resilience, GSA Annual Meeting, Phoenix, USA, September 2019

*Chan, P., Halfar, J., Adey, W.H., Lebednik, P., Rasher, D., Steneck, R., Norley, C., Pollman, S., Holdsworth, D.H (2019) Recent skeletal density decline in wild-collected Subarctic crustose coralline algae reveals climate change signature13th International Congress of Paleoceanography, Sydney, Australia, September 2019

Hetzinger, S., Halfar, J., Zajacz, Z., Wisshak, M. (2019) Early start of 20th century Arctic sea ice decline recorded in Svalbard coralline algae, 13th International Congress of Paleoceanography, Sydney, Australia, September 2019

*Chan, P., Halfar, J., Adey, W.H., Lebednik, P., Rasher, D., Steneck, R., Norley, C., Pollman, S., Holdsworth, D.H. (2019) Declining skeletal density in Subarctic crustose coralline algae, 5th International Sclerochronology Conference, June 16-21, Split, Croatia

*Zulian, M., Fietzke, J., Halfar, J. (2019) Are coralline red algae tougher than we thought - Industrial era pH seasonality and long-term trends in the Canadian Arctic Archipelago, 5th International Sclerochronology Conference, June 16-21, Split, Croatia

Rasmusson, L.M., Halfar, J., Hall-Spencer, J.M., Linderholm, H.W., (2019) Exploring the potential of Arctic coralline algae as a paleosalinity proxy. 5th International Sclerochronology Conference, June 16-21, Split, Croatia

Halfar, J., *Van der Linden, A., Moore, G.W.K. , *Shana, S., Tsay, S., Zajacz, Z. (2019) Reconstruction of Arctic Oscillation driven sea ice variability in Lancaster Sound, Canadian Arctic, using the long-lived coralline alga Clathromorphum compactum, 5th International Sclerochronology Conference, June 16-21, Split, Croatia

*Zulian, M., Fietzke, J., Halfar, J., 2019, Reconstructing Industrial era Arctic Ocean pH and Carbon System Dynamics with Clathromorphum compactum, Polar and High Altitude Environments Workshop, University of Toronto at Mississauga, May 6-7

*Leclerc, N., Halfar, J., * Zulian, M., Schöne, B., 2019, Coralline red algae respond to main drivers of Arctic climate: NAO/AO and increasing warming, Polar and High Altitude Environments Workshop, University of Toronto at Mississauga, May 6-7

Williams B., Chan, P., Ries, J., Westfield, I., Halfar J., Adey W.H (2018) Impact of changing environmental conditions on a high-latitude coralline algae climate proxy archive, AGU Fall Meeting 2018

Hetzinger, S., Halfar, J, Zajacz, Z., Wisshak, M. (2018) 200 years of northern Svalbard sea ice history recorded in encrusting coralline algae, AGU Fall Meeting

Williams, B., Adey, W., Halfar, J. (2018) Advancements in reconstructing high-latitude environmental change from the skeletons of crustose coralline algae, AGU Fall Meeting

*Leclerc, N, Halfar, J., Van der Linden, A., Hetzinger, S., Yin, Y. and Zajacz, Z. (2018) Testing the suitability of the coralline alga Clathromorphum compactum as a proxy for past sea ice cover in the arctic, GSA Annual Meeting, Indianapolis, USA

*Williams, S., Halfar, J., Nash, M., Kronz, A., Zajacz, Z. and Adey, W. (2018) A comparison of techniques for analysis of Mg/Ca ratios in the high-latitude coralline algal proxy climate archive Clathromorphum, GSA Annual Meeting, Indianapolis, USA

Williams, B., Williams, S., Anagnostou, E., Ries, J., Halfar, J., Rasher, D., Westfield, I., Adey, W. (2018) Refining the Mg/Ca-temperature proxy in crustose coralline algae: a case study in the genus Clathromorphum, Goldschmidt Conference, Boston, USA

Halfar, J., Shana, S., Moore, G.W.K., Tsay, S., Zajacz, Z. (2018) Reconstructing Sea Ice Cover in Lancaster Sound, Canadian Arctic Archipelago, using the long-lived coralline alga Clathromorphum compactum, European Geosciences Union, Annual Meeting, Vienna, Austria

Williams, S., Halfar, J., Adey, W., Kronz, A., Gagnon, P., Bélanger, D., Nash, M. (2018) Effects of light and temperature on Mg uptake in the coralline algal climate proxy archive Clathromorphum compactum, European Geosciences Union, Annual Meeting, Vienna, Austria

Williams, B., Chan, P., Halfar, J., Bimstead, D., Adey, W. (2018) Sclerochronological response of encrusting coralline algae to seawater variability. AGU Ocean Sciences Meeting, Portland, Oregon

Hetzinger, S., Halfar, J., Kronz, A., Simon, K., Adey, W., Steneck, R.S. (2017) Reproducibility of Clathromorphum compactum coralline algal Mg/Ca ratios and comparison to high-resolution sea surface temperature data, GeoBremen, Bremen, Germany, Sept 24-29

Williams, B., Halfar, J., Light, T., Hou, A., Zajacz, Z., Tsay, S. (2017) Comparison of Three Analytical Techniques to Measure Mg/Ca Values in High-Latitude Encrusting Coralline Algae, Goldschmidt Conference, Paris, France, Aug 13-18

*Chan, P., Halfar, J., Norley, C., Pollmann, S., Adey, W., Holdsworth, D. (2017) Micro-computed tomography: Applications for high-resolution skeletal density determinations. An example using annually-resolved crustose coralline algae. Ecosystem Studies of Subarctic and Arctic Seas Open Science Meeting, Tromsoe, Norway, June 11-15

*Chan, P., Halfar, J., Adey, W., Hetzinger, S., Zack, T., G.W.K. Moore, U.G. Wortmann, B. Williams, *A. Hou (2017) Multicentennial Record of Labrador Sea Primary Productivity and Sea-Ice Variability Archived in Coralline Algal Ba/Ca. Ecosystem Studies of Subarctic and Arctic Seas Open Science Meeting, Tromsoe, Norway, June 11-15

*Williams, S., Halfar, J., Zack, T., Hetzinger, S., Blicher, M., Juul Pedersen, T., Kronz, A. (2017) Comparing climate signals obtained from encrusting and free-living Southwest Greenland coralline algae, Geological Association of Canada Annual Meeting, Kingston, Ontario, Canada, May 15-20th

*Shana, S., Halfar, J., (2017) Reconstructing arctic sea ice cover from long-lived coralline algae, 16th annual Advances in Earth Sciences Research Conference, London, Ontario, Canada

*Delgado-Brand, M., Halfar, J. (2017) Regional distribution and spatial patterns of recent shallow-water benthic foraminifera from Punta Chivato, Gulf of California, Mexico, 16th annual Advances in Earth Sciences Research Conference, London, Ontario, Canada

*Pereira, C., Halfar, J. (2017) Benthic Foraminifera Assemblages from Isla San Jose, Gulf of California, Mexico, 16th annual Advances in Earth Sciences Research Conference, London, Ontario, Canada

Moore, G.W.K., Halfar, J., *Majeed, H., Adey, W., Kronz, A. (2017) Amplification of the Atlantic Multidecadal Oscillation at the end of the Little Ice Age, European Geophysical Union Annual Meeting, Vienna, Austria.

*Hou, A., ; Halfar, J., Adey, W., Wortmann, U., Williams, B., Chan, P. (2017) Coralline Algal Skeletal ?13C as a Multicentury Recorder of Carbon Dynamics in the Subarctic North Atlantic, European Geophysical Union Annual Meeting, Vienna, Austria.

*Chan, P., Halfar, J., Adey, W., Hetzinger, S., Zack, T., G.W.K. Moore, U.G. Wortmann, B. Williams, *A. Hou (2017) Multicentennial Record of Labrador Sea Primary Productivity and Sea-Ice Variability Archived in Coralline Algal Ba/Ca, European Geophysical Union Annual Meeting, Vienna, Austria.

Anhäuser, T., *Hook, B., Halfar, J., Greule, M, Keppler, F. (2017) Polar amplification of the early Eocene indicated by delta2H values of lignin methoxyl groups of mummified wood, European Geophysical Union Annual Meeting, Vienna, Austria

Moore, G.W.K., Halfar, J., *Majeed, H., Adey, W., Kronz, A. (2016) Amplification of the Atlantic Multidecadal Oscillation at the end of the Little Ice Age , American Geophysical Union, Fall Meeting 2016, San Francisco

*Humphreys, A.F., Halfar, J., Rivera, F., Manzello, D., Reymond, C.,Westphal, H., Riegl, B. (2016) El Niño–Southern Oscillation influence on biofacies dynamics of the shallow-water carbonate systems of the Galápagos Archipelago, Geological Society of America Annual Meeting, Colorado, USA, Sept 25-28th.

Nash, M., Adey, W., Halfar, J. (2016) Understanding cellular-scale controls on Mg uptake in crustose coralline algae, 4th International Sclerochronology Conference, Portland, Maine.

Hetzinger, S., Halfar, J., Kronz, A., Simon, K., Adey, W., Steneck, R. (2016) Reproducibility of Clathromorphum compactum coralline algal Mg/Ca ratios and calibration to high-resolution sea surface temperature data, 4th International Sclerochronology Conference, Portland, Maine.

*Williams, S., Halfar, J., Zack, T., Hetzinger, S., Blicher, M., Juul Pedersen, T., Kronz, A. (2016) Comparing climate signals obtained from encrusting and free-living Southwest Greenland coralline algae, 4th International Sclerochronology Conference, Portland, Maine.

*Chan, P., Halfar, J., Adey. W.., Lebednik, P., Steneck., R., Norley, C., Holdsworth, D. (2016) Recent decline in skeletal density and calcification rates of subarctic crustose coralline algae, 4th International Sclerochronology Conference, Portland, Maine.

KEYNOTE Halfar, J. (2016), Coralline Algal Proxy Development: Problems and Opportunities, 4th International Sclerochronology Conference, Portland, Maine.

Chan, P.*, Halfar, J., Adey, W., Hetzinger, S., Zack, T., Moore, K. (2016) Multicentennial Record of North Atlantic Primary Productivity and Sea-Ice Variability Archived in Coralline Algal Ba/Ca, American Geophysical Union, Ocean Science Meeting, New Orleans, USA

Williams, S.*, Halfar, J., Zack, T., Blicher, M., Pedersen, T., Kronz, A. (2016) Reconstructing sea surface temperature in Southwest Greenland using long-lived coralline algal buildups, American Geophysical Union, Ocean Science Meeting, New Orleans, USA

Williams, B., Halfar, J., DeLong, K., Smith, E., Steneck, R., Lebednik, P., Jacob, D., Fietze, J., Moore, K, (2015) Multi-centennial reconstruction of Aleutian climate from coralline algae, American Geophysical Union, Fall Meeting, San Francisco, USA

*Williams, S., Halfar, Zack, T., Blicher, T., Pederson, T. J., Kronz., A. (2015) Reconstructing sea surface temperature in Southwest Greenland using long-lived coralline algal buildups. Ilulissat Climate Days 2015, Ilulissat, Greenland.

*Chan, P., Halfar, J., Adey, W., Zack, T. (2014) Multi-centennial record of North Atlantic freshwater variability since the Little Ice Age archived in coralline algal Ba/Ca, American Geophysical Union Fall Meeting, San Francisco, Dec 14-19th.

Ng, J., Williams, B., Thompson, D.,Halfar, J. (2014) Developing a Forward Model of Encrusting Coralline Algae, American Geophysical Union Fall Meeting, San Francisco, Dec 14-19th.

Suskiewicz T.S., Adey W.,Halfar, J., Johnson L., Gagnon P., & MacGregor K. (2014) The Marine Environment over centuries past: using multi-century crustose corallines as biological temperature loggers throughout the N. Atlantic, Arctic Change, 8-12.12.14, Ottawa, Canada.

Sletten, H.R, Andrus, F., Gillikin, D.,Halfar, J. (2014) Preliminary growth and trace elemental characterization of rhodoliths (Lithothamnion sp.) from the Gulf of Panama, Panama, Geological Society of America Annual Meeting, Vancouver, Canada, Oct 26-29.

Halfar, J., *Chan, P., Lebednik, P., Norley, C., Holdsworth, D. Ocean Acidification: Centennial Calcification Rate Records from Subarctic Coralline Algae, Geologische Vereinigung Annual Meeting, Frankfurt, Germany, 22-24.9.2014

*Hook, B., Halfar, J., Gedalof, Z., Schulze, D. (2014) Paleocene/Eocene kimberlite-hosted mummified wood from the Canadian Arctic reveals multidecadal climate variability, Geologische Vereinigung Annual Meeting, Frankfurt, Germany, 22-24.9.2014

*Humphreys, A., Halfar, J., , Riegl, B., Reymond, C., Westphal, H., Rivera, F. (2014) Contrasting carbonate sediment facies in the Galápagos Islands – a result of oceanographic extremes, International Association of Sedimentologists Meeting, Geneva, Switzerland.

Halfar, J., Adey, W.H., Kronz, A., Hetzinger, S. (2014) Crustose coralline algae: A novel annual-resolution marine sea ice proxy, PAGES-Sea Ice Proxy Workshop 3, Bremerhaven, June 23-25, 2014.

Williams, B.*, Adey, W.H., Halfar, J. (2014) Seasonality in calcification, sclerochronology, and geochemistry in the encrusting coralline alga Clathromorphum compactum, Californian Goldschmidt Conference, Sacramento, California, June 2014.

Hetzinger, S., Halfar, J., Adey, W., Kronz, A., Zack, T. (2014) Crustose coralline algae as recorders of past climate and ocean variability, International joint workshop on coral reef environmental earth sciences, 24.-29.3.2014, Hokkaido University, Sapporo, Japan.

Chan, P., Halfar, J., Lebednik, P.A., Holdsworth, D., Norley, C. (2014) Centennial records of skeletal densities obtained from crustose coralline algae demonstrate decline in recent decades with no effect on calcification rates. American Geophysical Union, Ocean Science Meeting, Honolulu, February 2014.

Fietzke, J., Ragazzola, F., Halfar, J., Dietze, H., Foster, L.C. (2014) Imaging of boron isotopes via LA-MC-ICPMS for pH reconstruction in crustose coralline red algae on seasonal to centennial timescales. American Geophysical Union, Ocean Science Meeting, Honolulu, February 2014.

Hook, B., J. Halfar, Z. Gedalof, J. Bollmann, M.A. Rahman, J., Reyes, and D. Schulze. 2014. Stable isotope paleoclimatology of the Early Eocene using mummified wood from the Canadian Arctic. 9th International Conference on Dendrochronology. 13-17 January 2014. Melbourne, Australia.

Hook, B., J. Halfar, Z. Gedalof, J. Bollmann, M.A. Rahman, J., Reyes, and D. Schulze. 2014. Modified Brendel-cellulose extraction method for use with kimberlite-hosted mummified wood. 9th International Conference on Dendrochronology. 13-17 January 2014. Melbourne, Australia.

Halfar, J., Adey, W.H., Hetzinger, S. (2013) Coralline reconstructions of sea-ice cover and North Atlantic Oscillation, Palaeoweather Workshop, Mainz, Germany, Oct 10-11.

Fietzke, J., Ragazzola, F., Halfar, J., Dietze, H., Foster, L.C., Hansteen, T.H., Eisenhauer, A., Steneck, R.S. (2013) Isotope imaging via LA-MC-ICPMS: a ?11B study in marine carbonates, 22rd Goldschmidt Geochemistry Conference, Firenze, Italy, August 2013

Hook, B., Halfar, J., Bollmann, J., Gedalof, Z. (2013) Paleoclimatology of Early Paleogene Mummified Wood from the Canadian Arctic, Second American Dendrochronology Conference, Tucson, Arizona, May 2013.

Hetzinger S., Halfar J., Zack T., Mecking J., Kunz, B., Jacob D., Adey, W.H. (2013) Coralline algal Barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability, 3rd Int. Sclerochronology Conference, Bangor, Wales, May 2013.

Williams B., Halfar J., DeLong K., Hetzinger S., Steneck R.S., and Jacob D.E. (2012) Development of subarctic coralline algae as proxy archives: a Mg/Ca replication and calibration study, American Geophysical Union, Fall Meeting, San Francisco, USA, December 2012.

Halfar, J., Adey, W., Hetzinger, S., Williams, B., Steneck, R. (2012) Mid- and High-latitude coralline algal buildups and their use as paleoenvironmental archives, International Association of Sedimentologists Annual Meeting, Schladming, Austria. September 2012, KEYNOTE

Mecking, J.V., Hetzinger, S., Keenlyside, N. S., Halfar J. (2012) Marine proxy and model links between the extra-tropical North Pacific and North Atlantic on decadal timescales. Climate Change in High Latitudes, Bjerkness Centre 10-Years Anniversary Conference, Bergen, Norway, September 2012.

Chan, P., Halfar, J., Williams, B., Adey, W.H., Lebednik, P.A., Steneck, R.S. (2012) Interdecadal variability in coralline algal calcification rates in response to the Pacific Decadal Oscillation, 34th International Geological Congress, Australia, August 2012.

Ragazzola, F., Fietzke, J., Halfar, J., Dietze, H., Foster, L.C., Hansteen, T.H., Eisenhauser, A., 2012, Coralline algae as pH-recorders on seasonal to centennial timescales, Third International Symposium on the Ocean in a High-CO2 World, Monterey, California, Sep. 2012.

Fietzke, J., Ragazzola, F., Halfar, J., Dietze, H., Foster, L.C., Hansteen, T.H., Eisenhauser, A., 2012, Coralline algae as pH-recorders on seasonal to centennial timescales, 22nd Goldschmidt Geochemistry Conference, Montreal, Canada, June 2012.

Adey, W., Halfar, J., Williams, B., 2012, Biological and ecological factors controlling carbonate build-ups and producing a precision Arctic/Subarctic marine climate archive: the calcified alga Clathromorphum compactum, Geological Association of Canada Annual Meeting, St. Johns, Newfoundland, May 2012.

Halfar, J., Chan, P., Adey, W., Hetzinger, S., Williams, B., Steneck, R., Lebednik, P., 2012, Century-scale variability of Coralline Algal Calcification Rates in the North Pacific and North Atlantic, Geological Association of Canada Annual Meeting, St. Johns, Newfoundland, May 2012.

Halfar, J. (2012) Coralline algal calcification rates and geochemistry under different temperature and carbonate saturation conditions, Galapagos - natural laboratory for the study of climate and anthropogenic forcing, Workshop, Bremen, Germany, May 2012.

Halfar, J., Chan, P., Adey, W., Hetzinger, S., Williams, B., Steneck, R., Lebednik, P., 2012, Century-scale variability of Coralline Algal Calcification Rates in the North Pacific and North Atlantic, European Geophysical Union, Annual Meeting, Vienna, Austria, 20 April 2012.

Chan, P., Halfar, J., Williams, B., Adey, W.H., Lebednik, P.A., Steneck, R.S. (2012) Interdecadal Variability in Coralline Algal Calcification Rates in Response to the Pacific Decadal Oscillation, ICES, Mallorca, April 2012.

Williams, B., Halfar, J., Hetzinger, S., Adey, W.H., Steneck, R.S., Lebednik, P.A., Chan, P. (2012) Variable controls on subarctic coralline algal growth, American Geophysical Union, Ocean Science Meeting, Feb 2012.

Williams, B., Halfar, J., Hetzinger, S., Lebednik P.A., Steneck, R.S., Adey W.H., Fietzke J., Jacob, D. (2011) 350 years of Aleutian Island arc paleoceaographic change extracted from the skeletons of subarctic coralline algae, American Geophysical Union Fall Meeting, Dec 2011, San Francisco.

Mecking J. V. , Hetzinger S., Halfar, J., Keenlyside, N. S., Kronz, A.. Steneck R. S., Adey W. H., Lebednik P. A. (2011) Marine proxy evidence linking decadal North Pacific and Atlantic climate, American Geophysical Union Fall Meeting, Dec 2011, San Francisco.

Hook, B., Halfar, J., Bollmann, J., Gedalof, Z., and Schulze, D. (2011) Paleoclimatology of the Early Paleogene using Kimberlite-Hosted Mummified Wood from the Canadian Arctic, American Geophysical Union Fall Meeting, Dec 2011, San Francisco.

Hook, B., Halfar, J., Bollmann, J., Gedalof, Z., Walker, J., and Schulze, D. (2011) Paleoclimatology of the Early Paleogene using Stable Isotopes of Kimberlite-hosted Mummified Wood. ASITA: Advances in Stable Isotope Techniques and Applications. Queen's University, Kingston, ON, CA. June 12 - 15, 2011.

Boucher E., Halfar, J., Williams, B., Hetzinger, S., Steneck, R.S., Adey, W. (2011) Changes in coralline algal calcification as a possible indicator of sub-arctic ocean acidification. Advances in Earth Science Research Conference, Carleton University, Ottawa, Canada, March 25-27, 2011.

Keenlyside N., Hand, R., Tseng, W.-J., Hetzinger, S., Mecking, J., Halfar, J. (2010), Preliminary results: ECHAM5 T213 (50km), Simulation over mid-latitude SST fronts, JSPS-DFG workshop, Sapporo, Japan, 18-19.10.2010

Keenlyside N., Hetzinger, S., Mecking, J., Halfar, J. (2010) Are North Pacific and Atlantic multi-decadal variability related? Joint IFM-GEOMAR IO RAS – IAP RAS Workshop, 29.04.2010

Williams, B., Halfar, J, Hetzinger S., Steneck, R.S., Adey, W., Lebednik, P., Barth, M., 2010, Mg/Ca in coralline algae record 300 years of sea surface temperatures in the Bering Sea, 10th International Conference on Paleoceanography, Aug. 29-Sep. 3

Mallela, J., Kulfan C.M., *Hetzinger, S., Halfar, J. Dullo, C., Macrander, A., Grove, C., Zinke J., 2010,Tobago brain coral provides a long-term archive of south American river runoff, tropical climate variability and shifts in coral growth, Australian Coral Reef Society Annual Conference, Coffs Harbour, Australia, Sept. 10-12

Halfar, J., * Williams, B., *Hetzinger, S, Steneck, R., Adey, W.,, 2010, Skeletal density trends in coralline algae suggest ocean acidification impacts in the North Pacific and North Atlantic, 2nd International Sclerochronology Conference, Mainz, Germany, July 25-30

*Chan, P., Halfar, J., *Hetzinger, S., Steneck, R., Zack, T., Jacob, D., 2010, Is the Alaska Coastal Current becoming less saline? An example using coralline algal Ba/Ca ratios, 2nd International Sclerochronology Conference, Mainz, Germany, July 25-30

*Hetzinger, S., Kulfan C.M., Mallela, J., Halfar, J. Dullo, C., Macrander, A., Grove, C., Zinke J., 2010, Tobago coral record as a high-resolution archive of Amazon and Orinoco River outflow and tropical climate variability, 2nd International Sclerochronology Conference, Mainz, Germany, July 25-30

*Hetzinger, S., Halfar, J, Keenlyside, N., Mecking J., Kronz A., Steneck, R., Adey, W,. Lebednik, P.A., 2010, A link between North Pacific and North Atlantic climate on multidecadal time scales - new insights from coralline algae, 2nd International Sclerochronology Conference, Mainz, Germany, July 25-30.

*Chan, P., Halfar, J., *Hetzinger, S., Steneck, R., Zack, T., B. Kunz, D. Jacob, 2010,. Coralline red algae as recorders of past temperature and salinity variability of the Alaska Coastal Current, 2010 AGU Ocean Science Meeting, Portland, Oregon, Feb. 17-21.

*Chan, P., Halfar, J., *Hetzinger, S., Steneck, R., Zack, T., B. Kunz, D. Jacob, 2010,. Coralline red algae as recorders of past temperature and salinity variability of the Alaska Coastal Current, 2010 Alaska Marine Science Symposium, Anchorage, Alaska, Jan. 18-22.

Halfar, J., *Hetzinger, S. , Kronz, A., Steneck, R., Adey, A., and Lebednik, P., 2009, High-resolution Mg/Ca ratios in a coralline red alga as a proxy for Bering Sea temperature variations and teleconnections, Geological Society of America Annual Meeting, 18-21 October, 2009, Portland, USA.

*Chan, P., Halfar, J., *Hetzinger, S., Steneck, R., Zack, T., 2009, Coralline red algae records past temperature variability in the Alaska Coastal Current, PAGES, 3rd Open Science Meeting, 8-11 July, 2009, Corvallis, USA.

Halfar, J., *Hetzinger, S., Zack, T., Simon, K., Kronz, A., Robert S. Steneck, R., Adey, W., Lebednik, P., Schöne, B., Fietzke J., 2009, High-resolution analysis of trace elements in encrusting coralline red algae by laser ablation ICP-MS, International Fossil Algal Association - 6th Regional Symposium – Milan, Italy, June 30-July 5th.

Halfar, J., *Eisele, M., Riegl, B., *Hetzinger, S., Godinez-Orta, L., 2009, Acoustic mapping of rhodolith-dominated carbonates at Punta Chivato, Mexico, International Fossil Algal Association - 6th Regional Symposium – Milan, Italy, June 30-July 5th.

*Tripp Quezada, A.; Halfar, J.; Godínez, L., Borges Souza, J., 2009 (extended abstract), Biodiversity of Molluscs associated with a nontropical carbonate shelf in Punta Chivato, Gulf of California. 42nd Western Society of Malacologists Annual Meeting. Fullerton, California, June 23-27, pages 78-83.

Halfar, J., *Hetzinger, S., Zack, T., Simon, K., Kronz, A., Robert S. Steneck, R., Adey, W., Lebednik, P., Schöne, B., Fietzke J., 2009, High-resolution analysis of trace elements in encrusting coralline red algae by laser ablation ICP-MS, Goldschmidt, Davos, Switzerland, June 21-26, 2009

*Gamboa, G., J. Halfar, T. Zack, S., *Hetzinger, W. Adey, 2009, Mg/Ca ratios in coralline red algae as temperature proxies for reconstructing Labrador Current variability, American Geophysical Union, Spring Meeting, Toronto, Canada, 24th – 27th May 2009.

*Hetzinger, S., J. Halfar , T. Zack , B. Kunz, K., Simon, A. Kronz, W. Adey, P. A. Lebednik, R.S. Steneck, B.R. Schöne, 2009, High-resolution analysis of trace elements in encrusting coralline red algae by laser ablation ICP-MS, American Geophysical Union, Spring Meeting, Toronto, Canada, 24th – 27th May 2009.

Halfar, J., *Hetzinger, S. , Kronz, A., Steneck, R., Adey, A., and Lebednik, P., 2009, High-Resolution Mg/Ca Ratios in a Coralline Red Alga as a Proxy for Bering Sea Temperature Variations and Teleconnections, American Geophysical Union, Spring Meeting, Toronto, Canada, 24th – 27th May 2009.

Halfar, J., *C. Winsborough, *A. Omar, *S. Hetzinger, R.S. Steneck, P. A.Lebednik, 2009, Do coralline red algal growth increment widths archive paleoenvironmental information? European Geophysical Union, Annual Meeting, Vienna, Austria, 20 April 2009.

*Hetzinger, S., J. Halfar , T. Zack , K. Simon, A. Kronz, W. Adey, P. A. Lebednik, R.S. Steneck, B.R. Schöne, 2009, High-resolution analysis of trace elements in encrusting coralline red algae by laser ablation ICP-MS, European Geophysical Union, Annual Meeting, Vienna, Austria, 20 April 2009.

*Walker, J. J., J. Halfar, D. Schulze, Z. Gedalof, G. W. K. Moore, 2009, High-resolution reconstruction of Arctic paleoclimate derived from 53 million year old kimberlite-hosted Metasequoia wood, European Geophysical Union, Annual Meeting, Vienna, Austria, 20 April 2009.

*Gamboa, G. J. Halfar, T. Zack, *S. Hetzinger, W. Adey, 2009, Mg/Ca ratios in coralline red algae as temperature proxies for reconstructing Labrador Current variability, European Geophysical Union, Annual Meeting, Vienna, Austria, 20 April 2009.

*Tripp Quezada, A.; Halfar, J.; Godínez, L., Borges Souza, J., 2009. Biodiversidad de moluscos de fondos blandos asociados a sedimentos de carbonatos modernos en Bahía de Los Ángeles, Golfo de California. I Simposio de Ecología y Conservación S.O.S. NATURA. Santiago de Cuba. 6 - 10 de Abril, 2009.

*Tripp Quezada, A.; Halfar, J.; Godínez, L., Borges Souza, J., 2008, Biodiversity of Mollusks associated with a non-tropical carbonate shelf in the Gulf of California, 41st Annual Meeting, Western Society of Malacologists, Menlo Park, California, USA, June 5-8th 2008.

*Tripp Quezada, A.; Halfar, J.; Godínez, L., Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos en el arrecife de Cabo Pulmo, Golfo de California, Mexico, III Congreso Brasileiro de Oceanografia, Fortaleza, Brasil, 20-24 May, 2008.

*Hetzinger, S.; Halfar, J.; Kronz, A.; Steneck, R.; Adey, W.; Lebednik, P.A.; Schoene, B.R., 2008, High-resolution Mg/Ca ratios in crustose coralline red algae from the subarctic North Pacific – a record of past climate variability, European Geophysical Union, Annual Meeting, Vienna, Austria, 18 April 2008.

*Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos modernos en el Golfo de California, 1er. Congreso sobre la evolución geológica y ecológica del noroeste de

*Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos en el arrecife de Cabo Pulmo, Golfo de California, V Taller Internacional CONyMA, Havanna, Cuba, 3-7 March 2008

Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Biodiversity of Mollusks associated with a non-tropical carbonate shelf in the Gulf of California, 41st Annual Meeting, Western Society of Malacologists, Menlo Park, California, USA, June 5-8th 2008.

Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos en el arrecife de Cabo Pulmo, Golfo de California, Mexico, III Congreso Brasileiro de Oceanografia, Fortaleza, Brasil, 20-24 May, 2008.

Hetzinger, S.; Halfar, J.; Kronz, A.; Steneck, R.; Adey, W.; Lebednik, P.A.; Schoene, B.R., 2008, High-resolution Mg/Ca ratios in crustose coralline red algae from the subarctic North Pacific - a record of past climate variability, European Geophysical Union, Annual Meeting, Vienna, Austria, 18 April 2008.

Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos modernos en el Golfo de California, 1er. Congreso sobre la evolución geológica y ecológica del noroeste de Mexico, 21-23 of April 2008. Hermosillo Sonora, México

Tripp Quezada, A.; Halfar, J.; Godínez, Lucio, Borges Souza, J., 2008, Comunidades de moluscos asociados a ambientes de carbonatos en el arrecife de Cabo Pulmo, Golfo de California, V Taller Internacional CONyMA, Havanna, Cuba, 3-7 March 2008

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2007, Biodiversity of Molluscs Associated to a Nontropical Carbonate Shelf in San José Island, Gulf of California, 40th Annual Meeting Western Society of Malacologists, La Paz, Mexico, July 25-28 2007.

Halfar, J., Steneck, R., Moore, G.W.K., Röhl, J., Schöne, B., Fietzke, J., and Estes, J. 2007, Annual growth rates of coralline red algae reveal North Pacific-Bering Sea climate change and teleconnection patterns, 1st International Sclerochronology Conference, Florida, July 17-21, 2007.

Halfar, J., Steneck, R., Schöne, B., Moore, G. W. K., Joachimski, M., Kronz, A., Fietzke, J., and Estes J., 2007, Coralline alga reveals first marine record of subarctic North Pacific climate change, European Geophysical Union, Annual Meeting, Vienna, Austria, April 2007.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2007, Biodiversidad de Moluscos de Fondos Blandos Asociados a Ambientes de Carbonatos Modernos en Bahía de Los Angeles, Golfo de California; México. 5th Symposium Internacional sobre el Mar de Cortez, Sonora, Mexico, April 24-27, 2007.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2007,Biodiversidad de moluscos de fondos blandos asociados a ambientes de carbonatos modernos en Bahía de Los Ángeles, Golfo de California; México, XII Congreso Latinoamericano de Ciencias del Mar, Florianópolis, Brasil, April 15-19, 2007

Mutti, M., Halfar, J., 2007, Carbonate systems along temperature and nutrient gradients: theory and case studies, First International Workshop on the COREF Project, Okinawa, Japan, January 2007.

Fuentes-Yaco, C.; J. E. Valdez-Holguín; T. Platt; S. Sathyendranath; J. Halfar; L. Godinez Orta, J. M. Borges; E. Devred, 2006, Biological impact of Hurricane Ignacio (2003) in the Eastern Pacific Ocean as observed through MODIS data, Asia-Pacific Remote Sensing Conference, International Society for Optical Engineering, Nov. 13-17th, 2006, GOA, India.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2006, Biodiversidad de Moluscos de Fondos Blandos Asociados a Ambientes de Carbonatos Modernos en Bahía de Los Angeles, Golfo de California; México. Marcuba 2006, 7th Congress on Marine Sciences, Havanna, Cuba, Dec. 4-8th, 2006.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2006, Biodiversidad de Moluscos de Fondos Blandos del Arrecife de Cabo Pulmo, Golfo de California, México. Marcuba 2006, 7th Congress on Marine Sciences, Havanna, Cuba, Dec. 4-8th, 2006.

Halfar, J., Riegl, B., Godinez, L., Pelz, K., 2006, Sedimentary facies and geophysical mapping of the eastern Pacific’s northernmost reef-like setting (Cabo Pulmo, Mexico), Sediment 2006, Göttingen.

Halfar, J., Steneck, R., Joachimski, M., Kronz, A., Estes, J., 2006, An 85-year stable oxygen isotope record derived from a North Pacific coralline red alga, American Geophysical Union, Ocean Science Meeting, Honolulu, February 2006.

Steneck, R.S., Estes, J.A., Halfar, J., 2005, Sea Otters, Trophic cascades and Seward’s folly: Over two centuries of phase-shifts, regime shifts and the Little Ice Age in the Aleutians witnessed by a coralline alga, Benthic Ecology Meeting, April 2005, USA.

Halfar, J., Mutti, M., 2005, Global dominance of coralline red-algal facies: A response to Miocene oceanographic events. Carbonate Systems during the Oligocene-Miocene climatic transition, workshop, Universität Potsdam, Germany, February 2005.

Halfar, J., 2005, Coralline red algae as high-resolution paleoclimate archives- a monitoring and calibration study. 1st Japanese-German Frontiers of Science Symposium, Mainz, Germany.

Halfar, J., Nava-Sanchez E., Molina-Cruz A., 2004, Redeposited Shallow Water Non-Tropical Carbonates in the Southern Gulf of California, Mexico. 32nd International Geological Congress, Firenze, Italy.

Mutti, M., Halfar J., Knoerich A., John C., 2004, Carbonate Systems along Temperature And Nutrient Gradients: Modern and Miocene Examples. 32nd International Geological Congress, Firenze, Italy.

Strasser, M., Halfar, J., Riegl, B., Godinez-Orta, L., 2004, Acoustic mapping and sedimentology of bryomol carbonates in the Gulf of California, Mexico. Sediment 2004, Aachen, Germany, 2.-5. June.

Valdez-Holguín, J.E., Halfar, J., Godinez Orta, L., Hinojosa Larios, J.A., Borges, J.M., 2004, Variación latitudinal de clorofila a en la costa occidental del Golfo de California. Gulf of California Conference, Tucson, Arizona, June 2004.

Valdez-Holguín, J.E., Halfar, J. Godinez Orta, L., Gutierrez de Velasco, G., Borges, 2004, Effects of Hurricane Ignacio (August 2003) on near surface chlorophyll concentrations and water temperature at Cabo Pulmo, Baja California Sur, México. Gulf of California Conference, Tucson, Arizona, June 2004.

Halfar, J, Riegl, B., Godinez, L., 2004, Acoustic Mapping and Sediment Composition of the Northernmost East Pacific Coral Reef at Cabo Pulmo, Mexico, AGU Ocean Science Meeting, Portland, Oregon, January 2004.

Halfar, J., Kronz, A., Steneck., R., Carriquiry, J., Godinez, L., Iglesias, R., Joachimski, M. (invited speaker), 2004, Field monitoring and geochemical analysis of paleoclimate signals of tropical to cold-temperate coralline red algae, AGU Ocean Science Meeting, Portland, Oregon, January 2004.

Godínez-Orta, L., Gutiérrez de Velasco, G., Halfar, J., Valdez-Holguín, J.E., Borges, J.M., 2003, Water temperature variability along the west coast of the Gulf of California, AGU Fall Meeting, San Francisco, December 2003, p. 1235.

Halfar, J., Godinez-Orta, L., Mutti, M., Valdez-Holguin, J, Borges, J., 2003, Modern non-tropical carbonates calibrated against nutrients and temperature, Geological Society of America Annual Meeting, Seattle, Washington, Nov. 2003, p. 84.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2003, Variación de las comunidades y del crecimiento de moluscos asociados a ambientes de carbonatos modernos a través de un transecto de la zona templada a la subtropical del Golfo de California, México, X Congreso Latinoamericano sobre Ciencias del Mar, Costa Rica, Sept. 2003.

Halfar, J., Godinez-Orta, L., Valdez-Holguin, J., Borges, J., Mutti, M., 2003, Modern non-tropical carbonates calibrated against nutrients and temperature: an example from the Gulf of California, Mexico, Sediment 2003, Terra Nostra, v. 3/03, June 2003, p. 29.

Godínez-Orta, L., Gutiérrez de Velasco, G., Halfar, J., Valdez-Holguín, J.E., Borges, J.M, 2003, Variabilidad de la temperatura a lo largo de la costa oeste del Golfo de California, III Simposium Internacional sobre el Mar de Cortés, 6.- 9.5.2003, La Paz, Mexico.

Tripp-Quezada, A., Halfar, J., Godinez-Orta, L., Borges, J.M., 2003, Community variations and growth of mollusks in modern carbonate environments along a transect from the temperate to the subtropical realm: the Gulf of California, Mexico, III Simposium Internacional sobre el Mar de Cortés, 6.- 9.5.2003, La Paz, Mexico.

Godinez-Orta, L. Halfar, J., Valdez-Holguin, J.E., Borges, J.M, Gutiérrez-Velasco, G., 2003, Non-tropical carbonates calibrated against nutrients and temperature: an example from the Gulf of California, Mexico, III Simposium Internacional sobre el Mar de Cortés, 6.-9.5.2003, La Paz, Mexico.

Valdez-Holguín, J.E., Halfar, J., Godinez Orta, L., Hinojosa Larios, J.A., Borges, J.M., 2003, Variación latitudinal de clorofila a en la costa occidental del Golfo de California, III Simposium Internacional sobre el Mar de Cortés, 6.-9.5.2003, La Paz, Mexico.

Halfar, J., Ingle, J.C. Jr., 2002, Modern warm-temperate to subtropical shallow water benthic foraminiferal faunas of the Southern Gulf of California, Mexico, Sediment 2002, Darmstadt, Germany, Schriftenreihe Deutsche Geol. Ges., 17, p. 80.

Halfar, J., Ingle, J.C. Jr., Godinez-Orta, L., Goodfriend, G.A., 2001, Rhodolith dominated warm-temperate to subtropical carbonates of the southern Gulf of California, Mexico, International Association of Sedimentologists, 21st meeting of Sedimentology, Davos, Switzerland, p. 186.

Halfar, J., Mutti, M., Godinez-Orta, L., 2001, Controls on modern production and accumulation of non-tropical carbonate sediments along a transect from the temperate to subtropical realm: the Gulf of California, Mexico, International Association of Sedimentologists, 21st meeting of Sedimentology, Davos, Switzerland, p. 190.

Halfar, J., Mutti, M., Godinez-Orta, L., 2001, Transitional non-tropical carbonate environments of the Gulf of California, Mexico, 2001 Margins Meeting, Kiel, Germany, p. 79-80.

Halfar, J., Goodfriend, G., Ingle, J. C. Jr., Godinez-Orta, L., 2001, Holocene shallow water carbonate accumulation in a warm-temperate to subtropical regime: the southern Gulf of California, Mexico: 6.6.-8.6.2001, Sediment 2001, Jena, Germany, Schrift. Deutsch. Geol. Ges., v. 13, p. 44.

Mutti, M., Halfar, J., 2001, Carbonates from the Gulf of California, Mexico: A calibration of carbonate facies to margin paleoceanography. 10-12.5.2001, Aplacon-Meeting, Joint European Ocean Drilling Initiative, Lisbon, Portugal, p. 100-101.

Halfar, J., Godinez-Orta, L., Goodfriend, G., Mucciaroni, D. A., Ingle, J. C. Jr., 2000, Recent-Pleistocene warm-temperate carbonate environments of the southern Gulf of California, Mexico. 17. Geowiss. Lateinamerika-Symposium, 11.-13. Okt., Stuttgart, Germany, Profil, Bd. 18, p. 48.

Halfar, J., Godinez-Orta, L., Ingle, J.C. Jr., 2000, Ambientes Carbonatados Recientes En La Bahía De La Paz, Baja California Sur, México, XII Congreso Nacional de Oceanografía, Huatulco, Oaxaca, 22-26 mayo del 2000, p. 42.

Halfar, J., Godinez-Orta, L., Goodfriend, G., Mucciaroni, D. A., Ingle, J. C. Jr., 2000, Sedimentacion de Carbonatos Pleistocenicos-Holocenicos y Historia Tectonica del Area de La Paz, Baja California Sur, Mexico. V Reunion Int. Sobre Geologia de la Peninsula de Baja Calif. Sur, 25.4- 1.5., Loreto, Mexico, p. 32-33

Halfar, J., Zack, T., Kronz, A., Zachos, J., 1998, Palaeoenvironmental signals and growth rates of rhodoliths- a geochemical approach, Goldschmidt Conference Toulouse 1998, Mineralogical Magazine, Vol. 62A, part 2, p.559-560.

Goodfriend, G. A., Halfar, J., 1998, Application of Amino Acid Racemization to Detailed Chronostratigraphic Analysis of Holocene Sedimentary Sequences; Perspectives in Amino Acid and Protein Geochemistry, Washington, D.C., p.41.

Halfar, J., 1997, Recent Peritidal Carbonate Environments of the La Paz Area, Baja California Sur, Mexico: A Model for Subtropical Carbonate Deposition; AAPG Bulletin, Vol. 81, No. 10, p. 1775.

Halfar, J., Ingle, J.C., Jr. and Cruz-Orozco, R., Godinez-Orta, L., 1996, Modern Carbonate Sediments and Environments of the La Paz Region, Baja California Sur, Mexico; AAPG Annual Meeting, San Diego, p.58-59.

Halfar, J., 1995, Facies Architecture and Sedimentology of Fluvial Deposits: A Paleogene Example from the Weisselster Basin, Germany; AAPG Annual Meeting, Houston, p. 37.

Halfar, J., Ingle, J.C., and Cruz-Orozco, R., 1995, Mixed carbonate-siliciclastic sediments and environments of the La Paz region, Baja California Sur, Mexico; Third Intern. Meeting on Geology of the Baja California Peninsula, La Paz, Mexico, p. 80.

Halfar, J., Fink, I., Riegel, W., Walther, H., 1995, Faziesarchitektur und Floreninhalt eines paläogenen fluviatilen Systems im Tagebau Schleenhain bei Leipzig; 123. Jahrestagung des APP, Dresden, p. 8-9.


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