Changing marine productivity off northern Chile during the past 19 000 years: a multivariable approach

2004 ◽  
Vol 19 (4) ◽  
pp. 347-360 ◽  
Author(s):  
M. Mohtadi ◽  
O. E. Romero ◽  
D. Hebbeln
1999 ◽  
Vol 51 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Terry L. Jones ◽  
Douglas J. Kennett

AbstractMussel shells from central California coastal archaeological sites record changes in sea surface temperatures in the past 2000 years. Water temperatures, inferred from oxygen isotopes in the shells, were about 1°C cooler than present and stable between 2000 and 700 yr ago. Between about 700 and 500 yr ago, seasonal variation was greater than present, with extremes above and below historic levels. Water temperatures were 2–3°C cooler than today 500–300 yr ago. The interval of variable sea temperatures 700–500 yr ago partially coincided with an interval of drought throughout central California. A coincident disruption in human settlement along the coast suggests movements of people related to declining water sources. Quantities of fish bone in central coast middens dating to this same period are high relative to other periods, and the remains of northern anchovies, a species sensitive to changing oceanographic conditions, are also abundant. The continued use of local fisheries suggests that changes in settlement and diet were influenced more by drought than by a decrease in marine productivity, as fish provided a staple during an interval of low terrestrial productivity.


Author(s):  
Wilmar Salo ◽  
William C. Auferheide ◽  
Michael Madden ◽  
John Streitz ◽  
Jane Buikstra ◽  
...  

Ancient DNA methodology was applied to extract and amplify a segment of kinetoplast DNA of Trypanosoma cruzi in soft tissue specimens from about 300 spontaneously mummified human bodies from the Atacama Desert in northern Chile and southern Peru. A DNA probe was then employed to hybridize with the amplicon. Results indicate that about 41% of the population in that geographic area were infected with the trypanosome over the past 9000 years. The epidemiological implications of these findings are discussed. It is also emphasized that this and several other paleoepidemiological studies in progress have established that population-study cohorts of mummies now can generate statistically valid paleoepidemiological investigations capable of testing hypotheses. These reflect the maturation of the academic discipline of the scientific study of mummies.


2020 ◽  
Vol 27 (2) ◽  
pp. 225-228
Author(s):  
Diego Alonso García-Olaechea ◽  
César Lauraro Chávez-Villavicencio ◽  
Jorge Juan Novoa-Cova

Breeding colonies of Storm-petrels (family Hydrobatidae) are poorly known and can be difficult to find because they typically nest on islands in crevices and burrows inside caves. In the past decade, some breeding locations of the Wedge-rumped Storm-petrel (Hydrobates tethys kelsalli) have been reported on islands off central Peru and northern Chile. Here we report the northernmost breeding colony of this subspecies from Isla Foca, northern of Peru. In April 2006 we found 28 nests, of which 46% had chicks and 54% had eggs. Nests consisted of small holes in the rock with no nest material used for construction. Nesting season coincided with that of other reproductive zones found on the Peruvian coast. These results contribute to the knowledge of the distribution of reproductive colonies of this subspecies on the Peruvian coast.


2013 ◽  
Vol 9 (3) ◽  
pp. 1345-1373 ◽  
Author(s):  
J.-R. Riethdorf ◽  
D. Nürnberg ◽  
L. Max ◽  
R. Tiedemann ◽  
S. A. Gorbarenko ◽  
...  

Abstract. We used piston cores recovered in the western Bering Sea to reconstruct millennial-scale changes in marine productivity and terrigenous matter supply over the past ~180 kyr. Based on a geochemical multi-proxy approach, our results indicate closely interacting processes controlling marine productivity and terrigenous matter supply comparable to the situation in the Okhotsk Sea. Overall, terrigenous inputs were high, whereas export production was low. Minor increases in marine productivity occurred during intervals of Marine Isotope Stage 5 and interstadials, but pronounced maxima were recorded during interglacials and Termination I. The terrigenous material is suggested to be derived from continental sources on the eastern Bering Sea shelf and to be subsequently transported via sea ice, which is likely to drive changes in surface productivity, terrigenous inputs, and upper-ocean stratification. From our results we propose glacial, deglacial, and interglacial scenarios for environmental change in the Bering Sea. These changes seem to be primarily controlled by insolation and sea-level forcing which affect the strength of atmospheric pressure systems and sea-ice growth. The opening history of the Bering Strait is considered to have had an additional impact. High-resolution core logging data (color b*, XRF scans) strongly correspond to the Dansgaard–Oeschger climate variability registered in the NGRIP ice core and support an atmospheric coupling mechanism of Northern Hemisphere climates.


2020 ◽  
Vol 26 (12) ◽  
pp. 6767-6786 ◽  
Author(s):  
Audrey Limoges ◽  
Kaarina Weckström ◽  
Sofia Ribeiro ◽  
Eleanor Georgiadis ◽  
Katrine E. Hansen ◽  
...  

2012 ◽  
Vol 8 (6) ◽  
pp. 6135-6198 ◽  
Author(s):  
J.-R. Riethdorf ◽  
D. Nürnberg ◽  
L. Max ◽  
R. Tiedemann ◽  
S. A. Gorbarenko ◽  
...  

Abstract. We used piston cores recovered in the western Bering Sea to reconstruct millennial-scale changes in marine productivity and terrigenous matter supply over the past ~180 kyr. Based on a geochemical multi-proxy approach our results indicate closely interacting processes controlling marine productivity and terrigenous matter supply comparable to the situation in the Okhotsk Sea. Overall, terrigenous inputs were high, whereas primary production was low. Minor increases in marine productivity occurred during warm intervals of stage 5 and interstadials, but pronounced maxima were recorded during interglacials and Termination I. Seasonal sea-ice is suggested to act as the dominant transport agent for terrigenous material. From our results we propose glacial, deglacial, and interglacial scenarios for environmental change in the Bering Sea. These changes seem to be primarily controlled by insolation and sea-level forcing which affect the strength of atmospheric pressure systems and sea-ice growth. The opening history of the Bering Strait and the Aleutian passes is considered to have had an additional impact. Sea-ice dynamics are thought to drive changes in surface productivity, terrigenous inputs, and upper-ocean stratification. High-resolution core logging data (color b*, XRF scans) strongly correspond to the Dansgaard–Oeschger climate variability registered in the NGRIP ice core and support an atmospheric coupling mechanism of Northern Hemisphere climates.


2016 ◽  
Vol 85 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Matthieu Carré ◽  
Donald Jackson ◽  
Antonio Maldonado ◽  
Brian M. Chase ◽  
Julian P. Sachs

The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air–sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air–sea carbon flux in this region.


1991 ◽  
Vol 2 (3) ◽  
pp. 260-268 ◽  
Author(s):  
Larry W. Cartmell ◽  
Arthur C. Aufderheide ◽  
Angela Springfield ◽  
Cheryl Weems ◽  
Bernardo Arriaza

Coca-leaf chewing results in absorption of part of its cocaine content. Following absorption, cocaine and/or its stable metabolic product benzoylecgonine (BZE) may enter the chewer's hair follicles and subsequently be incorporated into the hair shafts. This article reports that a recently developed radioimmunoassay is capable of detecting BZE in hair samples from ancient, spontaneously mummified human remains. Results are provided from tests on hair samples of 163 individuals, representatives of populations from seven different cultures living at coastal and low valley sites in northern Chile during the past 4,000 years. These indicate that coca-leaf-chewing practices began in this area about 2,000 years ago. The practice seems to have been common in several subsequent cultural groups. In one of these—Maitas Chiribaya—the majority of both adult men and women indulged in this practice. Coca-leaf-chewing women probably transferred BZE to their fetuses and nursing infants.


2015 ◽  
Vol 11 (A29A) ◽  
pp. 115-117
Author(s):  
R. Chris Smith ◽  
Pedro Sanhueza ◽  
Malcolm G. Smith

AbstractThe AURA Observatory site in northern Chile, which includes Cerro Tololo and Cerro Pachon, has been operational for over 50 years now, facing a variety of challenges to its long-term future. The site now hosts over 20 operational telescopes, ranging from small projects with 0.4m telescopes to the Blanco 4m, the SOAR 4.1m, and the 8m Gemini-South telescopes. In addition, we have recently begun the construction of the Large Synoptic Survey Telescope (LSST) on the summit of Cerro Pachon. We summarize our efforts over the past 20-30 years to highlight the importance of site protection through education and public outreach as well as through more recent promotion of IDA certifications in the region and support for the World Heritage initiatives described by others in this conference.


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