All posts by cfunk

Archaeology, Marine Biology

Food Web Model for Vega Bay, Kiska Island

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Authors: Caroline Funk and Spencer A. Wood | February 20, 2015

Our team marine biologist, Dr. Spencer Wood, is building food webs as part of his research on marine communities. Spencer spent the 2014 field season in the intertidal zones near prehistoric Aleut village sites. His gear and clothes weighed more than he did; most days he went out into the rocky reefs wearing five or six layers of long underwear, fuzzies, and raingear – topped by warm hats and a PFD. He recorded the presence of species and counted them using formal data-collection procedures. Spencer also collected small tissue samples from some of the species, for isotope analysis in Dr. Nicole Misarti’s lab (see our previous post “Intertidal Foodweb Analysis” and the Wig-L-Bug video coming soon).

Spencer in the intertidal zone.
Dr. Wood sampling the intertidal zone below the 1,200 year old KIS-050 village midden. Image by B. Hoffman 2014.

Back in his office in Seattle, Spencer digitized his field data and combined them with information from an existing database of the known trophic relationships between species – who eats whom in the ocean. By melding observational data from the field with other information on the characteristics of the species that he observed, Spencer is able to create interesting depictions of the ecological communities that show how species are linked together into food webs around ancient village sites.

The Vega Bay Food Web Model

Wood2014_VegaBayFoodWebModel-01

The image here is a visual representation of the food web of the modern Vega Bay intertidal zone. It depicts the species (or taxonomic groups) present, their prey and predators, and the number of relationships among them. The image shows a network of predator-prey interactions. The size of the circle, called the node, indicates the number of links that any given taxon has with other taxa. A large diameter node indicates many connections. Lines curving clockwise from one node to another depict a predator eating its prey. Lines that curve counterclockwise indicate prey are being eaten by a predator.

Look at Bacilariophyta (diatoms) and Detritus (material from dead organisms) in the food web. These nodes are large, which means that they are linked to many other taxa. But, the links to them curve counterclockwise, which means that are being consumed by organisms like zooplankton (Copepods), snails (Littorina), and chitons (Mopalia). Gulls (the Larus node just right of center) have links that curve in both directions, showing that gulls are both a predator and a prey, depending on who they encounter.

Today people do not inhabit the region, so they are absent from the modern food web diagram. In the past, however, prehistoric Aleuts ate a wide variety of plants and animals from the intertidal zone and would be represented in a prehistoric food web as a large node with links to many different prey.

What Can We Learn From Food Webs?

Food webs are useful for understanding and predicting how changes will impact ecological systems. Fish and wildlife managers, for example, use them to estimate potential impacts of fishing and hunting and to set quotas. Other scientists use them to predict how changing temperatures will impact ecosystems. Our team is using the new food webs for Vega Bay and other sites in the Rat Islands to understand whether marine communities function differently today than they did thousands of years ago. Our team is also using information from our archaeological studies to construct food web depictions of ancient intertidal communities, from time periods when people lived in the Rat Islands. Including humans in these large, data-rich food web models allows us to better understand people’s relationships with other species in the marine environment. Soon, we’ll begin including other types of interactions into our networks, beyond just links between predators and their prey. We want to know more about the “non-trophic” roles of people, as culturally motivated resource collectors and members of the ecological community, and how they have impacted and been impacted by the dynamic environment over millennia.

Archaeology, Fairbanks Lab Research, Paleobotany, UAF Lab Research, University of Alaska

Peat Cores on Kiska Island

Author: C. Funk | University at Buffalo

Nancy Bigelow, our project specialist in pollen and plant macrofossils, took several peat cores and column samples from the area around our Summer 2014 camp – which happened to be situated near a newly described prehistoric Aleut village site (KIS-050). Her cores will give us a dated sequence of plant macrofossils (which come from the local area) and pollen (which may be wind-borne from a much broader area). Plants are sensitive to environmental changes like the amount of precipitation, temperature, windiness, soil chemistry, or amount of sunlight – and the impacts of human activities near them or interventions in their lifecycle.

Dr. Bigelow’s cores are the first from Kiska Island and her work will introduce entirely new information about the prehistoric environment shared by Aleuts, plants, and animals. Her research will combine with the archaeology team’s data to help us frame new questions about Aleut plant use and landscape manipulation. As the field images below show, processing a core is labor intensive, from the extraction process to lab sampling and analysis. Results from the processing of the first core should be ready this spring.

 

 

University at Buffalo Lab Research

The radiocarbon samples are off to the lab.

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Author: C. Funk | University at Buffalo | November 28, 2014

Fourteen little foil packets of charcoal, burned grass, and charred wood have headed off to the W.M. Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory. They’ll compete with Black Friday online shopping packages for space in the UPS plane, but I packed them tightly in a strong little box.

Samples 2

Once they arrive at the Keck CCAMS lab, Dr. John Southon will prepare the samples for analysis. They’ll go into the accelerator where they’ll be ionized and become negatively charged carbon atoms. Then, they’ll be accelerated to become positively charged atoms shooting along a path specific to carbon atoms. Carbon isotope 12, 13, and 14 atoms will deflect from the carbon path at different angles and they’ll be counted as they pass detectors in the accelerator. The counts will provide Dr. Southon with a ratio of stable and unstable carbon isotopes – and because unstable carbon 14 decays at a known rate from a known proportion in organic material he can tell me how old the carbon samples are.

Our job in the archaeology lab will be to associate the dated carbon samples with the rest of the materials. Everything hinges on how responsibly we make these associations. The archaeological materials will be considered older, younger, or more or less the same age as the dated materials depending positioning in the excavation. Similarly dated plant materials from the pollen cores taken in the surrounding landscape will tie developments in the environment to cultural events. Our prehistoric food web models will be based on the dates we assign to archaeological faunal materials according to their proximity to dated carbon samples. And, defining the long-term history of Aleut use of southern Kiska Island relies on the dates for all of the large and small sites we located during the summer’s field work.

We sent seven samples from KIS-050, a newly recorded prehistoric Aleut village site that we mapped and intensively tested during the Summer 2014 season. We are dating materials from a series of middens and house floors. The hope is that we have a strong temporal sequence and that all of the excavated materials can be placed in time ranges of hundreds of years.

Samples1

I sent seven samples from several other newly recorded Aleut village sites and smaller occupations that we located during the archaeological survey. We’ll know when these places were used at least one time in the past, but we won’t know for how long they were used by Aleuts, or for what. The dates from the smaller shovel tests we excavated on survey give us a broad idea of how intensively Aleuts used the whole area over hundreds of years.

These fourteen hard won little packets of charred material separate us from the old days of Aleutian archaeology, when everything was known simply as before, and nothing could be tracked over the lifetimes of individuals and families living in an ever-changing world.

Marine Biology, UAF Lab Research

Intertidal Food Web Analysis

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Author: Nicole Misarti | UAF | October 30, 2014

Courtney Sessum and Kelsey Saylor begin the process of dissecting intertidal samples in the UAF wet lab. Once they have been cleaned, dissected, freeze dried and powdered the samples will be run through an IRMS for nitrogen and carbon isotope analysis at the Alaska Stable Isotope Facility at UAF.

UAF Lab

Birds, University at Buffalo Lab Research, Zooarchaeology

Bird bones in the lab at Buffalo

Author: C. Funk | University at Buffalo | October 9, 2014

We’re working here in the Rat Islands research lab at University at Buffalo. It’s a Thursday afternoon – outside it’s windy and sunny, a perfect fall day. In here the lights are shining brightly on Ariel, Bobbi, and me. Bobbi is cataloging bone tools and I’ll talk to her about that a bit next week.

Ariel sorting bird bones.Today I’m interested in what Ariel is doing.

Ariel is a second year graduate student here in the department. She is planning to specialize in monumentality and colonialism in Europe for her dissertation research. She happens to have a skill set in bird osteology and that’s why she’s here with us.

“What are you doing over there?” I ask her. She rolls her eyes at me a little bit because I can clearly see what she is doing, “sorting a sample bag of bird bones into elements,” she says. After a moment she says, “I think this is just one bird, part of the thoracic area and the wings. The vertebrae are articulating and the tarsometatarsi are paired.” We do a quick check in the bird book and it seems to be a small cormorant. Our comparative osteological collection will arrive from the Burke Museum in Seattle next week. We’ll identify the bird then.

Ariel with a mostly intact bird skeleton.Bobbi and Ariel and I are talking about excavation sampling strategies and their impacts on which elements were collected and on the patterns of bone presence we’ll use to talk about Aleut resource exploitation, processing, and discard strategies. Ariel says that she thinks she is seeing more humerii and ulnae in general – those are the bones in the bird wing. But some samples have a higher concentration of leg elements. “Mostly,” Ariel looks up at me from her study of the bones on the table, “mostly we seem to have more wings than butts.” Bobbi looks interested at this. “Maybe they were making a lot of bird butt hats. In the field, Debbie said Aleuts made duck butt hats for babies. They cut the legs off and sewed the thighs so the feathered legs stuck up like feathery little ears.” We talk about wearing bird butt hats for a bit before we settle back into work.

I ask Ariel if she has worked with birds at other sites. She has. She worked on the Pompeii Archaeological Research Project: Porta Stabia. But she worked with flotation samples there, so the specimens were small and fragmented. She says that the Rats materials are larger, that there are more whole elements, and that the preservation of this collection is excellent.

“Why birds?” I ask Ariel. “Because another researcher asked me what I’d like to look at. I picked birds because I don’t want to do fish and it turns out birds aren’t studied often. People think they are difficult but they are actually easy to identify to family. There’s a lot of room for research.”

Ariel and Bobbi working.I’ve stopped bothering Bobbi and Ariel and they are working away. I can hear the bones shuffling around on the table in front of Ariel, and the keyboard clattering while Bobbi enters artifact catalog data on the lab computer.