Fred Andrus

Associate Professor|Department Chair

  • fandrus@ua.edu
  • (205) 348-5177
  • 2003 Bevill


BA, Anthropology, The University of Georgia, 1990

MA, Anthropology, The University of Georgia, 1995

PhD, Geology, The University of Georgia, 2000

Post-Doctoral, Savannah River Ecology Laboratory

Research Interests

My research focuses on developing and applying new proxies relevant to reconstructing paleoclimate variation, often in the Pleistocene and Holocene. Methodologically, I focus on isotopic and elemental archives derived from microsampling accretionary carbonate skeletons. This sampling includes mollusk valves, corals, and fish otoliths. I have particular interest in reconstructing how climate influences organisms, including humans, especially as related to paleoecology.  This approach often necessitates the investigation of the life history of organisms that may act as paleoclimate indicators and the use of archaeological remains as a source of paleoenvironmental data.



Micromilling a clam valve for geochemical analysis.


Current Research Projects

Radiocarbon upwelling proxies:
I have been pursing upwelling-related research in coastal Peru and Chile for a number of years with several students and colleagues. Most recently Miguel Etayo (Ph.D. 2010), Christie Jones (MS 2010), and I measured radiocarbon profiles in various species of mollusks from the coast of Peru to better understand past and present upwelling and radiocarbon reservoir effects associated with El Niño/Southern Oscillation (ENSO). This was part of a NSF funded project in collaboration with colleagues at the University of Maine and the University of Arizona. We are grateful to a large number of Peruvian archaeologists who are providing critical collaboration on this project. Several journal papers resulted from this work and more are being prepared for submission now.

Near Chanquillo Peru

Miguel Etayo and colleagues hiking to Chanquillo, Peru.

Mollusk growth and biomineralization:
My students and I study the biomineralization processes and sclerochronology of several
mollusk species. For example, Jiexin Wei (MS 2014) investigated the utility of geochmical records measured in Peruvian Semele corrugata valves to determine season of capture and climate change. We are also working on:

Crassostrea virginica
Mercenaria spp.
Pachychilus spp. – jute snails
Choromytilus chorus
Aulacomya ater 
Atlantic, Pacific, and Gulf of Mexico Donax spp.
Rangia cuneata
Trachycardium procerum
Protothaca asperima

Thins tip crop

Thin section in transmitted light showing fine-scale growth increments in a Rangia cuneata valve.

Molluscan nitrogen isotopes:
Jestina Hansen (MS 2011) and I worked with a colleagues at Dauphin Island Sea Lab (DISL)  to assess if nitrogen isotopes preserved in mollusks can give insight into past coastal and marine nitrogen variability. Jestina  focused on comparing different extraction methods. Heather Black (MS 2014) investigated the impacts of diagenesis on mollusk nitrogen isotope records and measuring prehistoric N variation in ancient and modern oyster shells from the Chesapeake Bay area to assess anthropogenic nitrogen inputs over time. Taylor Payne, a current MS student, is conducting a similar study in the Charleston, SC harbor area.

Heather collecting Chesapeake oysters

Heather collecting oysters from Chesapeake Bay.

Tropical gastropod proxy development:

Kelley Rich (Ph.D. candidate) is examining the paleoclimatological utility of geochemical records contained in Central American gastropods (Pachychilus spp. – also called jute snails). These snails are common in Maya sites and Kelley hopes that their shell geochemistry may give insight into past rainfall patterns and season of capture.

She is monitoring streams in Belize, sampling wild snail shells, and growing snails under controlled conditions in our lab.


Kelley and Christie working in the sample preparation lab.

Coralline algae:

Hillary Sletten, (Ph.D. 2016) conducted several projects focused on developing and applying novel climate/environment proxies in coralline algae. She was awarded a fellowship to conduct research in Panama through the Smithsonian Tropical Research Institute where she collected rhodoliths and performed controlled mesocosm experiments. Additionally, she is analyzed geochemical profiles in encrusting algae from Greenland.

Rhodolith collecting

Hillary collecting rhodoliths along the Pacific coast of Panama.

Robin Cobb (MS Marine Science 2014) and I are studying the geochemistry of deep water Stylasterid (e.g. Stylaster erubescens) corals to assess growth and biomineralization patterns. This research is funded in part by NOAA and we are collaborating with colleagues at NOAA and several universities. Descriptions of the cruises to the Charleston Bump and Blake Plateau can be found at:




We are also studying the geochemistry of the shallow water Stylaser roseus from the Caribbean in collaboration with colleagues from UA Biological Sciences.


Robin steering the ROV on a research cruise.

Midden Geoarchaeology:
I am working with colleagues in many regions of North and South America using mollusk geochemistry, biogeography, and related techniques to study shell middens. Our goals are often to assess past human subsistence strategies, season of occupation and resource use, site formation processes, and other questions relating to archaeology.  I am presently conducting NSF-funded research into seasonality of subsistence practices along the northern Coast of the Gulf of Mexico with colleagues from UGA and USA. I am doing similar analyses from the Graveline Site, Mississippi excavated by colleagues here at UA. I have long-standing collaborative projects in the Georgia Bight investigating how midden sclerochronology can give insight into season of occupation, past subsistence strategies, site formation processes, and central place foraging models. Jiexin Wie (MS, 2014) analyzed Semele spp. valves from Peru to assess their utility as seasonality proxies. Additionally Oindrila Das, postdoctoral researcher in our laboratory, investigated the precision with which one can measure past season of capture in some common midden taxa. Most recently Ph.D. student Christine Bassett (MS, 2016) is analyzing modern and ancient butter clam shells from the west coast of Canada and Alaska. Her MS research is profiled here.

Christine collecting butter clams on Kodiak Island

Christine collecting butter clams in Kodiak Island, Alaska

Other Projects:
I am working on several other issues that do not fit neatly in the above categories. Some examples include geochemical variation in Cretaceous clams from the Mississippi Embayment, fish migration patterns measured in otolith geochemistry, and sediment core proxies from estuarine and lacustrine environments in the Northern Gulf of Mexico. I have also begun exploring some projects in coastal China and recently traveled to visit Ocean University.

Research Group Members

Aislyn Galford, Marine Science/Geology BS student

Christine Bassett, Ph.D. student

Representative Publications

Black*, H. D., Andrus, C. F. T., Lambert, W. J, Rick, T., and Gillikin, D. P., 2017. δ15N values  in Crassostrea virginica shells provides earliest direct evidence for nitrogen loading to Chesapeake Bay. Scientific Reports. 7: 44241; doi: 10.1038/srep44241.

Sletten*, H. R., Andrus, C. F. T., Guzman, H. and Halfar, J., 2017. Re-evaluation of using rhodolith growth patterns for paleoenvironmental reconstruction: An example from the Gulf of Panama. Palaeogeography, Palaeoclimatology, Palaeoecology. 465: 264–277.

Darrow, E. S., Carmichael, R. H., Andrus, C. F. T, and Jackson, E. H., 2017. From middens to modern estuaries, oyster shells sequester source-specific nitrogen. Geochimica et Cosmochimica Acta. 202: 39–56.

Waselkov, G. A., Andrus, C. F. T, and Plumb, G. E.,eds. 2016. A State of Knowledge of the Natural, Cultural, and Economic Resources of the Greater Mobile-Tensaw River Area. Natural Resources Report NPS/NRSS/BRD/NRR 2016/1243. Biological Resources Division, National Park Service, Fort Collins, CO. pp.240.

Plumb, G. E., Waselkov, G. A., Andrus, C. F. T., and Finch B., 2016. A greater Mobile-Tensaw area: connections and consequences. In Waselkov, G. A., Andrus, C. F. T, and Plumb, G. E., eds. A State of Knowledge of the Natural, Cultural, and Economic Resources of the Greater Mobile-Tensaw River Area. Natural Resources Report NPS/NRSS/BRD/NRR 2016/1243. Biological Resources Division, National Park Service, Fort Collins, CO. p. 185-193.

Gagnon, C. M., Andrus, C. F. T., Ida, J., and Richardson, N. 2015, Local water source variation and experimental chicha de maíze brewing: implications for interpreting human hydroxyapatite δ18O values in the Andes. Journal of Archaeological Science: Reports. 4: 174–181.

Thompson, V. D., Pluckhahn, T. J., Das, O. and Andrus, C. F. T. 2015, Assessing village life and monument construction (cal. AD 65-1070) along the Central Gulf Coast of Florida through stable isotope geochemistry. Journal of Archaeological Science: Reports. 4: 111–123.

Blitz, J, H., Andrus, C. F. T., and Downs, L. 2014, Sclerochronological measures of seasonality at a Late Woodland mound on the Mississippi Gulf Coast. American Antiquity 79: 697-711.

Etayo-Cadavid*, M. F., Andrus, C. F. T., Jones, K. B., Hodgins, G. W. L., Sandweiss, D. H. Uceda-Castillo, S., and Quilter, J. 2013. Marine radiocarbon reservoir age variation in Donax obesulus shells from Northern Peru: Late Holocene evidence for extended El Niño. Geology 41: 599–602.

Pérez-Huerta, A. Etayo-Cadavid, M. F., Andrus, C. F. T., Jeffries, T. E., Watkins, C., Street, S. C., and Sandweiss, D. S. 2013 El Niño impact on mollusk biomineralization – Implications for trace element proxy reconstructions and the paleo-archeological record. PLoS ONE 8: e54274.

Andrus C. F. T. 2012. Isotope sclerochronology in southeastern US archaeology to estimate season of capture. in Reitz, E. J, Quitmyer, I. R., and Thomas, D. H. eds. Seasonality and Human Mobility Along the Georgia Bight. American Museum of Natural History Anthropological Papers 97: 123-133 (invited).

Andrus C. F. T. 2011. Shell midden sclerochronology. Quaternary Science Reviews 30: 2892-2905 (invited).

Andrus, C. F. T., and Thompson, V. D. 2011. Determining the habitats of mollusk collection at the Sapelo Island Shell Ring complex, USA using oxygen isotope sclerochronology: Journal of Archaeological Science 39: 215-228.

Thompson, V. D. and Andrus, C. F. T., 2011, Evaluating mobility, monumentality, and feasting at the Sapelo Island Shell Ring Complex: American Antiquity 76: 315-343.

Jones, K..B., Hodgins, G.W.L., Etayo-Cadavid*, M. F., Andrus, C. F. T., and Sandweiss, D. H., 2010, Centuries of marine radiocarbon reservoir age variation within archaeological Mesodesma donacium shells from southern Peru: Radiocarbon 52: 1207-1214.

Jones, Kevin.B., Hodgins, Gregory W.L., Andrus, C. Fred T., and Etayo-Cadavid*, Miguel F., 2010. Interpreting molluscan marine reservoir ages in a variable-upwelling environment: Palaios.25: 126-131. DOI: 10.2110/palo.2009.p09-050r.

Jones, Kevin. B., Hodgins, Gregory W.L., Etayo-Cadavid*, Miguel F., and Andrus, C. Fred T., 2009. Upwelling signals in radiocarbon from early 20th century Peruvian bay scallop (Argopecten purpuratus) shells: Quaternary Research 72: 452-456. DOI: 10.1016/j.yqres. 2009.07.008.

Romanek Christopher S., Beard, Brian L., Anbar, Ariel D. and Andrus, C. Fred T., 2009. Non traditional stable isotopes in the environmental sciences, in Aelion, C. M., Hohener, P., Hunkeler, D.,  and Aravena, R. eds., Environmental isotopes in bioremediation and microbial degradation processes. Boca Raton, FL , CRC Press, pp. 383-433.

Andrus, C. Fred T., and Rich*, Kelley W. 2008. A preliminary assessment of oxygen isotope fractionation and growth increment periodicity in the estuarine clam Rangia cuneataGeo-Marine Letters. DOI: 10.1007/s00367-008-0109-3.

Reitz, Elizabeth J., Andrus, C. Fred T., and Sandweiss, Daniel H. 2008. Ancient fisheries and marine ecology of coastal Peru. In Human Impacts on Ancient Marine Ecosystems. edited by Torben C. Rick and Jon M. Erlandson, University of California Press. pp. 125-145.

Andrus, C. Fred T. and Crowe, Douglas E., 2008. Isotope analysis as a means for determining season of capture for Mercenaria. In Native American Landscapes of St Catherine’s Island, Georgia. edited by David Hurst Thomas. American Museum of Natural History, Anthropological Papers, 88: 498-518.

Andrus, C. Fred T., Sandweiss, Daniel. H. and Reitz, Elizabeth J. 2008. Climate change and archaeology: The Holocene history of El Niño on the coast of Peru. In Case Studies in Environmental Archaeology, (Second Edition). edited by Elizabeth J. Reitz, C. Margaret Scarry, and Sylvia J. Scudder. Plenum Press, New York. pp. 143-157.

Jones, Kevin B., Hodgins, Gregory W. L., Dettman, David L., Andrus, C. Fred T., Nelson, April, and Etayo-Cadavid*, Miguel F. 2007. Seasonal variations in Peruvian marine reservoir age from pre-bomb Argopecten purpuratus shell carbonate. Radiocarbon 49: 877-888.

Sandweiss, Daniel H., Maasch, Kirk A., Andrus, C. Fred T., Reitz, Elizabeth J., Riedinger-Whitmore, Melanie, Richardson, James B., and Rollins, Harold B. 2007 Mid Holocene Climate and Culture Change in Coastal Peru. In Climate Change and Cultural Dynamics: A Global Perspective on Mid-Holocene Transitions. Edited by David G.Anderson, Kirk A. Maasch, and Daniel H. Sandweiss, Academic/Elsevier Press. pp. 25-50.

Andrus, C. Fred T., Hodgins, Gregory W. L., Sandweiss, Daniel H., and Crowe, Douglas E. 2005 Molluscan radiocarbon as a proxy for El Niño-related upwelling variation in Peru. In Isotopic and Elemental Tracers of Late Quaternary Climate Change, edited by Donna Surge and German Mora. Geological Society of America Special Paper 395: 13-19.

Jones, Douglas S., Quitmyer, Irvy R., and Andrus, C. Fred T. 2005. Oxygen isotopic evidence for greater seasonality in Holocene shells of Donax variabilis from Florida. Palaeogeography, Palaeoclimatology, Palaeoecology. 228: 96-108.

Quitmyer, Irvy R., Jones, Douglas S. and Andrus, C. Fred T. 2005 Seasonal shell growth and oxygen isotopes (δ18O) in the variable coquina clam, Donax variabilis Say, 1822: A modern analogue to determine the season of resource procurement during the Late Archaic Period of coastal northeast Florida, USA. In Archaeomalacology: Molluscs in Former Environments of Human Behavior. Proceedings of the Archaeomalacology Symposium of the 9th International Council for Zooarchaeology. edited by Daniella Bar-Yosef Mayer. Oxbow Press, Oxford, UK. pp.18-28

Sandweiss, Daniel H., Maasch, Kirk A., Chai, Fei., Andrus, C. Fred T., and Reitz, Elizabeth J. 2004. Geoarchaeological evidence for fish regime shift linked to multidecadal Pacific climate change. Quaternary Research 61: 330-334.

Jones, Douglas S., Quitmyer, Irvy R., and Andrus, C. Fred T. 2004 Seasonal shell growth and longevity in Donax variabilis from northeastern Florida: Evidence from oxygen isotopes. Journal of Shellfish Research 23(3): 707-714.

Andrus, C. Fred T. and Crowe, Douglas E. 2002. Alteration of otolith aragonite: Effects of prehistoric cooking methods on otolith chemistry. Journal of Archaeological Science. 29: 291-299.

Andrus, C. Fred T., Crowe, Douglas E., Sandweiss, Daniel H., Reitz, Elizabeth J., and Romanek, Christopher S. 2002. Otolith d18O record of mid-Holocene sea surface temperature in Peru. Science 295: 1508-1511.

Andrus, C. Fred T., Crowe, Douglas E. and Romanek, Christopher. S. 2002. Oxygen isotope record of the 1997-1998 El Niño in Peruvian sea catfish (Galeichthys peruvianus) otoliths. Paleoceanography 17(5): 1053-1060 – doi:10.1029/2001PA000652.

Andrus, C. Fred T. and Crowe, Douglas E. 2000. Geochemical analysis of Crassostrea virginica as a method to determine season of capture. Journal of Archaeological Science 27: 33-42

Weinand, Daniel C., Andrus, C. Fred T., and Crook, Morgan. R. 2000. The identification of cownose ray (Rhinoptera bonasus) as a seasonal indicator species and implications for coastal Mississippian subsistence modeling. Southeastern Archaeology 19: 156-162

*denotes student