Diatoms and other siliceous indicators track the ontogeny of a bofedal (wetland) ecosystem in the Peruvian Andes

Botany ◽  
2021 ◽  
Author(s):  
Connor King ◽  
Neal Michelutti ◽  
Carsten Meyer-Jacob ◽  
Richard Bindler ◽  
Pedro Tapia ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Ice Core ◽  
Water System ◽  
Open Water ◽  
Ice Age ◽  
Peruvian Andes ◽  
Peat Core ◽  
The Andes ◽  
Recent Warming ◽  
The Many

Recent warming in the Andes is affecting the region’s water resources including glaciers and lakes, which supply water to tens of millions of people downstream. High altitude wetlands, known locally as bofedales, are an understudied Andean ecosystem despite their key role in carbon sequestration, maintaining biodiversity, and regulating water flow. Here, we analyze subfossil diatom assemblages and other siliceous bioindicators preserved in a peat core collected from a bofedal in Peru’s Cordillera Vilcanota. Basal radiocarbon ages show the bofedal likely formed during a wet period of the Little Ice Age (1520-1680 CE), as inferred from nearby ice core data. The subfossil diatom record is marked by several dynamic assemblage shifts documenting a hydrosere succession from an open-water system to mature peatland. The diatoms appear to be responding largely to changes in hydrology that occur within the natural development of the bofedal, but also to pH and possibly nutrient enrichment from grazing animals. The rapid peat accretion recorded post-1950 at this site is consistent with recent peat growth rates elsewhere in the Andes. Given the many threats to Peruvian bofedales including climate change, overgrazing, peat extraction, and mining, these baseline data will be critical to assessing future change in these important ecosystems.

Ice-Core Pollen Record of Climatic Changes in the Central Andes during the last 400 yr

2005 ◽  
Vol 64 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Kam-biu Liu ◽  
Carl A. Reese ◽  
Lonnie G. Thompson
Keyword(s):  
Little Ice Age ◽  
Ice Core ◽  
Climatic Changes ◽  
Ice Age ◽  
Striking Similarity ◽  
Pollen Record ◽  
Dry Period ◽  
Proxy Records ◽  
Ice Cap ◽  
Ice Accumulation

AbstractThis paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases�"a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. During the dry period xerophytic shrubs expanded to replace puna grasses on the Altiplano, as suggested by a dramatic drop in the Poaceae/Asteraceae (P/A) pollen ratio. The environment around Sajama was probably similar to the desert-like shrublands of the Southern Bolivian Highlands and western Andean slopes today. The striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano.

scholarly journals Little Ice Age (Neoglacial) Paleoenvironmental Conditions At Siple Station, Antarctica

1990 ◽  
Vol 14 ◽  
pp. 199-204 ◽  
Author(s):  
Ellen Mosley-Thompson ◽  
Lonnie G. Thompson ◽  
Pieter M. Grootes ◽  
N. Gundestrup
Keyword(s):  
Little Ice Age ◽  
Regional Differences ◽  
Meteorological Data ◽  
Ice Core ◽  
Observational Evidence ◽  
Ice Age ◽  
Temperature Pattern ◽  
South Pole ◽  
Atmospheric Conditions ◽  
Spatially Distributed

The 550-year records of δ18O and dust concentrations from Siple Station, Antarctica suggest warmer and less dusty atmospheric conditions from 1600 to 1830 A.D. which encompasses much of the northern hemisphere Little Ice Age (LIA). Dust and δ18O data from South Pole Station indicate that the opposite conditions (e.g. cooler and more dusty) were prevalent there during the LIA. Meteorological data from 1945–85 show that the LIA temperature opposition between Amundsen-Scott and Siple, inferred from δ18O, is consistent with the present spatial distribution of surface temperature. There is some observational evidence suggesting that under present conditions stronger zonal westerlies produce a temperature pattern similar to that of the LIA. These regional differences demonstrate that a suite of spatially distributed, high resolution ice-core records will be necessary to characterize the LIA in Antarctica

Characterization of the Medieval Climate Anomaly, Little Ice Age and recent warming in northern Lapland

2017 ◽  
Vol 37 ◽  
pp. 1257-1266 ◽  
Author(s):  
Tomi P. Luoto ◽  
E. Henriikka Kivilä ◽  
Marttiina V. Rantala ◽  
Liisa Nevalainen
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
Climate Anomaly ◽  
Recent Warming

scholarly journals Tree-ring radiocarbon reveals reduced solar activity during Younger Dryas cooling

2020 ◽  
Author(s):  
Adam Sookdeo ◽  
Bernd Kromer ◽  
Florian Adolphi ◽  
Jürg Beer ◽  
Nicolas Brehm ◽  
...  
Keyword(s):  
Solar Activity ◽  
Tree Ring ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Core ◽  
Younger Dryas ◽  
Ice Age ◽  
The North ◽  
Long Duration ◽  
Clear Sign

<p>The Younger Dryas stadial (YD) was a return to glacial-like conditions in the North Atlantic region that interrupted deglacial warming around 12900 cal BP (before 1950 AD). Terrestrial and marine records suggest this event was initiated by the interruption of deep-water formation arising from North American freshwater runoff, but the causes of the millennia-long duration remain unclear. To investigate the solar activity, a possible YD driver, we exploit the cosmic production signals of tree-ring radiocarbon (<sup>14</sup>C) and ice-core beryllium-10 (<sup>10</sup>Be). Here we present the highest temporally resolved dataset of <sup>14</sup>C measurements (n = 1558) derived from European tree rings that have been accurately extended back to 14226 cal BP (±8, 2-σ), allowing precise alignment of ice-core records across this period. We identify a substantial increase in <sup>14</sup>C and <sup>10</sup>Be production starting at 12780 cal BP is comparable in magnitude to the historic Little Ice Age, being a clear sign of grand solar minima. We hypothesize the timing of the grand solar minima provides a significant amplifying factor leading to the harsh sustained glacial-like conditions seen in the YD.</p>

Pattern and Forcing of Northern Hemisphere Glacier Variations During the Last Millennium

1986 ◽  
Vol 26 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Stephen C. Porter
Keyword(s):  
Northern Hemisphere ◽  
Little Ice Age ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Phase Lag ◽  
Mountain Glacier ◽  
Radiocarbon Dates ◽  
Glacier Fluctuations ◽  
Decadal Scale

Time series depicting mountain glacier fluctuations in the Alps display generally similar patterns over the last two centuries, as do chronologies of glacier variations for the same interval from elsewhere in the Northern Hemisphere. Episodes of glacier advance consistently are associated with intervals of high average volcanic aerosol production, as inferred from acidity variations in a Greenland ice core. Advances occur whenever acidity levels rise sharply from background values to reach concentrations ≥1.2 μequiv H+/kg above background. A phase lag of about 10–15 yr, equivalent to reported response lags of Alpine glacier termini, separates the beginning of acidity increases from the beginning of subsequent ice advances. A similar relationship, but based on limited and less-reliable historical data and on lichenometric ages, is found for the preceding 2 centuries. Calibrated radiocarbon dates related to advances of non-calving and non-surging glaciers during the earlier part of the Little Ice Age display a comparable consistent pattern. An interval of reduced acidity values between about 1090 and 1230 A.D. correlates with a time of inferred glacier contraction during the Medieval Optimum. The observed close relation between Noothern Hemisphere glacier fluctuations and variations in Greenland ice-core acidity suggests that sulfur-rich aerosols generated by volcanic eruptions are a primary forcing mechanism of glacier fluctuations, and therefore of climate, on a decadal scale. The amount of surface cooling attributable to individual large eruptions or to episodes of eruptions is simlar to the probable average temperature reduction during culminations of Little Ice Age alacier advances (ca. 0.5°–1.2°C), as inferred from depression of equilibrium-line altitudes.

Little Ice Age Evidence from a South-Central North American Ice Core, U.S.A.

1996 ◽  
Vol 28 (1) ◽  
pp. 35 ◽  
Author(s):  
D. L. Naftz ◽  
R. W. Klusman ◽  
R. L. Michel ◽  
P. F. Schuster ◽  
M. M. Reddy ◽  
...  
Keyword(s):  
North American ◽  
Little Ice Age ◽  
Ice Core ◽  
Ice Age ◽  
South Central

scholarly journals Estimating South Cascade Glacier (Washington, U.S.A.) mass balance from a distant radiosonde and comparison with Blue Glacier

2001 ◽  
Vol 47 (159) ◽  
pp. 579-588 ◽  
Author(s):  
L. A. Rasmussen ◽  
H. Conway
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Little Ice Age ◽  
Ice Age ◽  
The Past ◽  
Recent Warming ◽  
Flux Model ◽  
Present Area

AbstractA simple flux model using twice-daily measurements of wind, humidity and temperature from standard upper-air levels in a distant radiosonde estimated winter balance of South Cascade Glacier, Washington, U.S.A., over 1959–98 with error 0.24 m w.e. Correlation between net and winter balance is strong; the model estimates net balance with error 0.53 m w.e. Over the past 40 years, average net balance of South Cascade Glacier has been strongly negative (−0.46 m w.e.), and it has been shrinking steadily. In comparison, 200 km west-southwest at Blue Glacier, the average balance has been less negative (−0.13 m w.e); that glacier has undergone little change over the 40 years. Balance histories of the two glaciers are positively correlated (r = +0.54), and South Cascade has been more out of balance than Blue, presumably because it is still adjusting to climate change since the Little Ice Age. Recent warming and drying has made the net balance of both glaciers strongly negative since 1976 (−0.84 m w.e. at South Cascade, −0.56 m w.e. at Blue). If South Cascade Glacier were in balance with the 1986–98 climate, it would be about one-quarter of its present area.

scholarly journals Large changes in biomass burning over the last millennium inferred from paleoatmospheric ethane in polar ice cores

2018 ◽  
Vol 115 (49) ◽  
pp. 12413-12418 ◽  
Author(s):  
Melinda R. Nicewonger ◽  
Murat Aydin ◽  
Michael J. Prather ◽  
Eric S. Saltzman
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Little Ice Age ◽  
Ice Core ◽  
Stable Carbon Isotope ◽  
Ice Cores ◽  
Ice Age ◽  
Climate Forcing ◽  
Medieval Period ◽  
Highly Sensitive

Biomass burning drives changes in greenhouse gases, climate-forcing aerosols, and global atmospheric chemistry. There is controversy about the magnitude and timing of changes in biomass burning emissions on millennial time scales from preindustrial to present and about the relative importance of climate change and human activities as the underlying cause. Biomass burning is one of two notable sources of ethane in the preindustrial atmosphere. Here, we present ice core ethane measurements from Antarctica and Greenland that contain information about changes in biomass burning emissions since 1000 CE (Common Era). The biomass burning emissions of ethane during the Medieval Period (1000–1500 CE) were higher than present day and declined sharply to a minimum during the cooler Little Ice Age (1600–1800 CE). Assuming that preindustrial atmospheric reactivity and transport were the same as in the modern atmosphere, we estimate that biomass burning emissions decreased by 30 to 45% from the Medieval Period to the Little Ice Age. The timing and magnitude of this decline in biomass burning emissions is consistent with that inferred from ice core methane stable carbon isotope ratios but inconsistent with histories based on sedimentary charcoal and ice core carbon monoxide measurements. This study demonstrates that biomass burning emissions have exceeded modern levels in the past and may be highly sensitive to changes in climate.

Climatic Fluctuations in Northern Patagonia during the Last 1000 Years as Inferred from Tree-Ring Records

1990 ◽  
Vol 34 (3) ◽  
pp. 346-360 ◽  
Author(s):  
Ricardo Villalba
Keyword(s):  
Tree Ring ◽  
Little Ice Age ◽  
Ice Age ◽  
Dry Period ◽  
Climatic Fluctuations ◽  
Northern Patagonia ◽  
The Andes ◽  
Weather Stations ◽  
Fitzroya Cupressoides

AbstractMillennium-old alerce trees (Fitzroya cupressoides (Mol.) Johnst.) have been used to develop a 1120-year reconstruction of the summer temperature departures for the Andes of northern Patagonia in Argentina. Four main climatic episodes can be distinguished in this proxy paleoclimatic record. The first, a cold and moist interval from A.D. 900 to 1070, was followed by a warm-dry period from A.D. 1080 to 1250 correlative with the Medieval warm epoch of Europe. Afterward, a long, cold-moist period followed from A.D. 1270 to 1670, peaking around A.D. 1340 and 1650. These cold maxima are contemporaneous with two principal Little Ice Age events registered in the Northern Hemisphere. Warmer conditions then resumed between A.D. 1720 and 1790. These episodes are supported by glaciological and palynological data in Patagonia. Following a cold period in the early 1800s, tree-ring indices have oscillated around the long-term mean, except for a warmer period from A.D. 1850 to 1890. Correlations between the Rio Alerce reconstruction and the regional weather stations indicate that the tree-ring variations are correlated with a homogeneous summer weather pattern covering Patagonia east of the Andes from 38° to 50°S.

Sign in / Sign up

Export Citation Format

Share Document