Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fish story linked to climate cycle

15.06.2004


Old fish bones can tell scientists about more than what people used to eat. They can also provide clues to the climate in which those people lived. In the scientific journal Quaternary Research, a team led by three University of Maine scientists reports using fish bones from an archaeological site in Peru to describe the timing of Pacific Ocean climate cycles linked to El Nino.



The report provides new evidence for a theory stating that biological cycles in the world’s oceans reflect subtle changes in climate. Industrial scale fish harvesting can also affect fish populations and thus make it difficult to discern the relationship between fisheries and climate.

The UMaine research points to changes in fisheries that pre-date modern harvesting. Those changes are thus more likely to be climate related.


The paper is titled "Geoarchaeological evidence for multidecadal natural climatic variability and ancient Peruvian fisheries." Co-authors are: from UMaine, archaeologist Dan Sandweiss, Kirk Maasch of the Climate Change Institute, Fei Chai of the School of Marine Sciences; and from the University of Georgia, Fred Andrus and Elizabeth Reitz.

With data gleaned from excavations in the ancient village of Lo Demás just south of modern day Lima, the researchers reported that a shift from anchovy to sardine abundance occurred at about 1500 A.D. Evidence for a climate shift at about the same time is contained in annual snowfall rates recorded in Andean glacial ice cores. Those cores show that the warm phase of the El Nino Southern Oscillation climate cycle contributes to lower snow fall rates. A reduction in anchovies and an increase in sardines also occur in those phases.

Sandweiss and a different research team excavated the Lo Demás site in the early 1980s as part of his doctoral studies. "Lo Demás was a specialized fish processing site," says Sandweiss, lead author on the Quaternary Research paper.

Native people used the site to gut fish and hang them to dry. "Because of the dry climate, the bones are well preserved," he says. "We found the post holes and the drip lines in the soil above the racks where the fish were hung. The soil was still saturated with fish oil. There were 500-year-old pottery shards that still smelled like rotten fish," Sandweiss adds.

When he was working at Lo Demás, Sandweiss did not look to climate for an explanation of the shift from anchovy to sardine abundance. It wasn’t until other researchers in the last five years began reporting modern evidence for such a connection throughout the Pacific Ocean that he went back to the Lo Demás data.

"The rare combination of location, high density of fish bones, and good chronological control make this an excellent site to study Pacific Ocean climate change," he says.

Over the past century, sardines and anchovies have experienced boom and bust cycles that are almost mirror images of each other. When anchovies are abundant, sardines tend to be less abundant, and vice-versa.

Since each species has a different life cycle and requires different temperature and nutrient conditions, scientists have suggested that Pacific Ocean climate shifts back and forth between a "sardine regime" and an "anchovy regime." Each regime is marked by different temperature, circulation and nutrient patterns.

In an article published in the journal Science in 2003, a research team led by Francisco Chavez of the Monterrey Bay Aquarium Research Institute documented anchovy and sardine harvesting cycles over the past century in Japan, California and Peru. They linked these cycles to climate patterns such as El Nino, the periodic warming of the eastern Pacific that plays havoc with the weather.

The work by Sandweiss, et al. extends the El Nino connection back to about 500 years ago at the end of the Inca Empire in Peru. "This strongly suggests that variability in the fisheries had to be linked to the climate, that this was a climate issue rather than a fish harvesting issue," Sandweiss says.

Anchovies were far more common than sardines in much older Peruvian archaeological sites stretching back as far as 8,000 years ago, the report notes. Such findings are consistent with an El Nino frequency that was less frequent than what is occurring in modern times.

The anchovy-sardine rollercoaster is not the first biological cycle to be linked to climate. Scientists have found similar evidence in ancient corals, tree rings and mollusk shells. In previous reports published in the journal Science, Sandweiss and colleagues have linked changes in mollusk species and temple building activities to shifts in the frequency of El Nino.

Dan Sandweiss | EurekAlert!
Further information:
http://www.umaine.edu/

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>