Fred Andrus

Fred Andrus



  • PhD, Geology, The University of Georgia, 2000
  • MA, Anthropology, The University of Georgia, 1995
  • BA, Anthropology, The University of Georgia, 1990

Research Areas

  • Paleontology, Paleoclimatology, and Paleoecology


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 a 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.

clam valve
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 Ni√Īo/Southern Oscillation (ENSO). This was part of an 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
Thin section in transmitted light showing fine-scale growth increments in a Rangia cuneata valve.
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 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 oysters from Chesapeake Bay.
Heather collecting oysters from the 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.

Hillary collecting rhodoliths along the Pacific coast of Panama
Hillary collecting rhodoliths along the Pacific coast of Panama

Robin Cobb (MS Marine Science 2014) and I are studying the geochemistry of deepwater 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 the following links:

Investigating the Charleston Bump (NOAA)

Estuary to the Abyss: Exploring Along the Latitude 31-30 Transect (NOAA)

Exploring Deep Sea Coral (NOAA)

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.
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 the 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 the 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, a 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. Learn more about her MS research.

Christine collecting butter clams in Kodiak Island, Alaska
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.

Selected Publications

Selected publications of the past 10 years. Highlighted text links to complete articles through institutional repositories. * Denotes student author.