76 results match your criteria: "School of Earth and Sustainability[Affiliation]"

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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  • An amendment to the original paper has been released.
  • This amendment includes updates or corrections to the initial content.
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An extensive new multi-proxy database of paleo-temperature time series (Temperature 12k) enables a more robust analysis of global mean surface temperature (GMST) and associated uncertainties than was previously available. We applied five different statistical methods to reconstruct the GMST of the past 12,000 years (Holocene). Each method used different approaches to averaging the globally distributed time series and to characterizing various sources of uncertainty, including proxy temperature, chronology and methodological choices.

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  • Forests can play a significant role in reducing climate change impacts and offering additional benefits to society, but they face increasing climate-related threats like fire and drought that may weaken their ability to absorb carbon.
  • Recent scientific advancements in understanding forest physiology and ecology are enhancing our ability to evaluate these risks to forest stability.
  • Improved risk assessment can guide policymakers in utilizing forests more effectively as natural solutions for climate change.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Despite the importance of seed dispersal as a driving process behind plant community assembly, our understanding of the role of seed dispersal in plant population persistence and spread remains incomplete. As a result, our ability to predict the effects of global change on plant populations is hampered. We need to better understand the fundamental link between seed dispersal and population dynamics in order to make predictive generalizations across species and systems, to better understand plant community structure and function, and to make appropriate conservation and management responses related to seed dispersal.

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A comprehensive database of paleoclimate records is needed to place recent warming into the longer-term context of natural climate variability. We present a global compilation of quality-controlled, published, temperature-sensitive proxy records extending back 12,000 years through the Holocene. Data were compiled from 679 sites where time series cover at least 4000 years, are resolved at sub-millennial scale (median spacing of 400 years or finer) and have at least one age control point every 3000 years, with cut-off values slackened in data-sparse regions.

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Concentrations of dissolved uranium (U) and arsenic (As) above drinking water standards in unregulated water sources pose various human health risks. Although high natural background concentrations may occur in some environments (Runnells et al. 1992), anthropogenic contamination concerns are especially troublesome on the Navajo Nation (NN), where past U mining activity may have contaminated water supplies.

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  • The Younger Dryas boundary layer at Abu Hureyra, Syria, is around 12,800 years old and contains high levels of meltglass, nanodiamonds, microspherules, and charcoal, indicating significant geological events.
  • The composition of the meltglass shows a mix of local sediment and meteoritic material, with evidence pointing to extremely high temperatures (up to 2200°C) during its formation, ruling out common sources like fires or lightning.
  • The findings suggest that a cosmic event may have impacted the area, aligning with similar high-temperature evidence found at other sites globally, linked to events occurring around the same time.
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The future response of the Antarctic ice sheet to rising temperatures remains highly uncertain. A useful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which experienced warmer polar temperatures and higher global mean sea level (GMSL) (+6 to 9 m) relative to present day. LIG sea level cannot be fully explained by Greenland Ice Sheet melt (∼2 m), ocean thermal expansion, and melting mountain glaciers (∼1 m), suggesting substantial Antarctic mass loss was initiated by warming of Southern Ocean waters, resulting from a weakening Atlantic meridional overturning circulation in response to North Atlantic surface freshening.

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This study explores the relationships of AM fungal abundance and diversity with biotic (host plant, ungulate grazing) and abiotic (soil properties, precipitation) factors in the Serengeti National Park, Tanzania. Soil and root samples were collected from grazed and ungrazed plots at seven sites across steep soil fertility and precipitation gradients. AM fungal abundance in the soil was estimated from the density of spores and the concentration of a fatty acid biomarker.

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Plant diversity is critical to the functioning of ecosystems, potentially mediated in part by interactions with soil biota. Here, we characterised multiple groups of soil biota across a plant diversity gradient in a long-term experiment. We then subjected soil samples taken along this gradient to drought, freezing and a mechanical disturbance to test how plant diversity affects the responses of soil biota and growth of a focal plant to these disturbances.

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A large volcanic sulfate increase observed in ice core records around 1450 C.E. has been attributed in previous studies to a volcanic eruption from the submarine Kuwae caldera in Vanuatu.

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Consistent multi-decadal variability in global temperature reconstructions and simulations over the Common Era.

Nat Geosci

June 2019

PAGES International Project Office, Bern, Switzerland.

Article Synopsis
  • Multi-decadal surface temperature changes are influenced by both natural factors and human activities, making it important to identify their contributions for better climate sensitivity estimates.
  • The study presents 2,000-year-long global temperature reconstructions using various statistical methods that show consistent multi-decadal temperature fluctuations similar to modeled simulations.
  • The analysis indicates that volcanic aerosol forcing significantly affected pre-industrial temperature variability, while recent warming trends in the late 20th century stand out as particularly unusual compared to historical patterns.
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Variation in life-history strategies can affect metapopulation dynamics and consequently the composition and diversity of communities. However, data sets that allow for the full range of species turnover from colonization to extinction over relevant time periods are limited. The late Quaternary record provides unique opportunities to explore the traits that may have influenced interspecific variation in responses to past climate warming, in particular the rate at which species colonized newly suitable habitat or went locally extinct from degrading habitat.

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Parasites can shape the structure and function of ecosystems by influencing both the density and traits of their hosts. Such changes in ecosystems are particularly likely when the host is a predator that mediates the dynamics of trophic cascades. Here, we experimentally tested how parasite load of a small predatory fish, the threespine stickleback, can affect the occurrence and strength of trophic cascades and ecosystem functioning.

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  • Climate records show large fluctuations over longer timescales, raising questions about climate models' ability to replicate these changes.
  • The study finds that both simple and complex climate models can replicate observed climate behavior across various timescales, indicating that the ocean plays a key role in the system's long-term memory of climate factors.
  • While climate models generally capture global temperature trends well, there are still unresolved differences in regional predictions, particularly relating to the deep ocean's initial conditions.
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The latitudinal temperature gradient between the Equator and the poles influences atmospheric stability, the strength of the jet stream and extratropical cyclones. Recent global warming is weakening the annual surface gradient in the Northern Hemisphere by preferentially warming the high latitudes; however, the implications of these changes for mid-latitude climate remain uncertain. Here we show that a weaker latitudinal temperature gradient-that is, warming of the Arctic with respect to the Equator-during the early to middle part of the Holocene coincided with substantial decreases in mid-latitude net precipitation (precipitation minus evapotranspiration, at 30° N to 50° N).

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The ability to accurately predict ecosystem drought response and recovery is necessary to produce reliable forecasts of land carbon uptake and future climate. Using a suite of models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assessed modeled net primary productivity (NPP) response to, and recovery from, drought events against a benchmark derived from tree ring observations between 1948 and 2008 across forested regions of the US and Europe. We find short lag times (0-6 months) between climate anomalies and modeled NPP response.

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Translocation is used by managers to mitigate the negative impacts of development on species. Moving individuals to a new location is challenging, and many translocation attempts have failed. Robust, posttranslocation monitoring is therefore important for evaluating effects of translocation on target species.

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Cryptic pigmentation of prey is often thought to evolve in response to predator-mediated selection, but pigmentation traits can also be plastic, and change with respect to both abiotic and biotic environmental conditions. In such cases, identifying the presence of, and drivers of trait plasticity is useful for understanding the evolution of crypsis. Previous work suggests that cryptic pigmentation of freshwater isopods (Asellus aquaticus) has evolved in response to predation pressure by fish in habitats with varying macrophyte cover and coloration.

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Enhanced peak growth of global vegetation and its key mechanisms.

Nat Ecol Evol

December 2018

Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.

The annual peak growth of vegetation is critical in characterizing the capacity of terrestrial ecosystem productivity and shaping the seasonality of atmospheric CO concentrations. The recent greening of global lands suggests an increasing trend of terrestrial vegetation growth, but whether or not the peak growth has been globally enhanced still remains unclear. Here, we use two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in annual peak vegetation growth (that is, GPP and NDVI).

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Species faced with rapidly shifting environments must be able to move, adapt, or acclimate in order to survive. One mechanism to meet this challenge is phenotypic plasticity: altering phenotype in response to environmental change. Here, we investigated the magnitude, direction, and consequences of changes in two key phenology traits (fall bud set and spring bud flush) in a widespread riparian tree species, Populus fremontii.

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Island biogeography theory is one of the most influential paradigms in ecology. That island characteristics, including remoteness, can profoundly modulate biological diversity has been borne out by studies of animals and plants. By contrast, the processes influencing microbial diversity in island systems remain largely undetermined.

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Anaerobic microsites have an unaccounted role in soil carbon stabilization.

Nat Commun

November 2017

Earth System Science Department, Stanford University, Via Ortega 473, Stanford, CA, 94305, USA.

Soils represent the largest carbon reservoir within terrestrial ecosystems. The mechanisms controlling the amount of carbon stored and its feedback to the climate system, however, remain poorly resolved. Global carbon models assume that carbon cycling in upland soils is entirely driven by aerobic respiration; the impact of anaerobic microsites prevalent even within well-drained soils is missed within this conception.

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