scholarly journals New insights from XRF core scanning data into boreal lake ontogeny during the Eemian (Marine Isotope Stage 5e) at Sokli, northeast Finland

2017 ◽  
Vol 89 (1) ◽  
pp. 352-364 ◽  
Author(s):  
Malin E. Kylander ◽  
Anna Plikk ◽  
Johan Rydberg ◽  
Ludvig Löwemark ◽  
J. Sakari Salonen ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Base Cation ◽  
Marine Isotope Stage ◽  
Climate History ◽  
Air Temperatures ◽  
Xrf Core Scanning ◽  
Development Processes ◽  
Northeast Finland ◽  
Lake Ontogeny ◽  
Over Time

AbstractBiological proxies from the Sokli Eemian (Marine Isotope Stage 5e) paleolake sequence from northeast Finland have previously shown that, unlike many postglacial records from boreal sites, the lake becomes increasingly eutrophic over time. Here, principal components (PC) were extracted from a high resolution multi-element XRF core scanning dataset to describe minerogenic input from the wider catchment (PC1), the input of S, Fe, Mn, and Ca-rich detrital material from the surrounding Sokli Carbonatite Massif (PC2), and chemical weathering (PC3). Minerogenic inputs to the lake were elevated early in the record and during two abrupt cooling events when soils and vegetation in the catchment were poor. Chemical weathering in the catchment generally increased over time, coinciding with higher air temperatures, catchment productivity, and the presence of acidic conifer species. Abiotic edaphic processes play a key role in lake ontogeny at this site stemming from the base cation- and nutrient-rich bedrock, which supports lake alkalinity and productivity. The climate history at this site, and its integrated effects on the lake system, appear to override development processes and alters its long-term trajectory.

scholarly journals Multi-year particle fluxes in Kongsfjorden, Svalbard

2018 ◽  
Vol 15 (17) ◽  
pp. 5343-5363 ◽  
Author(s):  
Alessandra D'Angelo ◽  
Federico Giglio ◽  
Stefano Miserocchi ◽  
Anna Sanchez-Vidal ◽  
Stefano Aliani ◽  
...  
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Ocean Circulation ◽  
Progressive Increase ◽  
Physical Parameters ◽  
Air Temperatures ◽  
Inorganic Matter ◽  
Particle Fluxes ◽  
Particulate Fluxes ◽  
Over Time

Abstract. High-latitude regions are warming faster than other areas due to reduction of snow cover and sea ice loss and changes in atmospheric and ocean circulation. The combination of these processes, collectively known as polar amplification, provides an extraordinary opportunity to document the ongoing thermal destabilisation of the terrestrial cryosphere and the release of land-derived material into the aquatic environment. This study presents a 6-year time series (2010–2016) of physical parameters and particle fluxes collected by an oceanographic mooring in Kongsfjorden (Spitsbergen, Svalbard). In recent decades, Kongsfjorden has been experiencing rapid loss of sea ice coverage and retreat of local glaciers as a result of the progressive increase in ocean and air temperatures. The overarching goal of this study was to continuously monitor the inner fjord particle sinking and to understand to what extent the temporal evolution of particulate fluxes was linked to the progressive changes in both Atlantic and freshwater input. Our data show high peaks of settling particles during warm seasons, in terms of both organic and inorganic matter. The different sources of suspended particles were described as a mixing of glacier carbonate, glacier siliciclastic and autochthonous marine input. The glacier releasing sediments into the fjord was the predominant source, while the sediment input by rivers was reduced at the mooring site. Our time series showed that the seasonal sunlight exerted first-order control on the particulate fluxes in the inner fjord. The marine fraction peaked when the solar radiation was at a maximum in May–June while the land-derived fluxes exhibited a 1–2-month lag consistent with the maximum air temperature and glacier melting. The inter-annual time-weighted total mass fluxes varied by 2 orders of magnitude over time, with relatively higher values in 2011, 2013, and 2015. Our results suggest that the land-derived input will remarkably increase over time in a warming scenario. Further studies are therefore needed to understand the future response of the Kongsfjorden ecosystem alterations with respect to the enhanced release of glacier-derived material.

scholarly journals Managers Fail to Innovate and Academics Fail to Explain How

2018 ◽  
Vol 14 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Deborah Dougherty
Keyword(s):  
Emerging Economies ◽  
Climate Changes ◽  
Business Models ◽  
Business Processes ◽  
New Products ◽  
Grand Challenge ◽  
Social Changes ◽  
Development Processes ◽  
Investor Returns ◽  
Over Time

I am stunned by the failure of so many organizations to create the capability for generating streams of new products and services over time. Organizations capable of ongoing innovation can create more profits, more value, more employment, more growth, and more adaptability to transformations in technologies and markets (BCG study of investor returns). Generating streams of innovation is even more important now, especially for organizations in emerging economies, because industrial transformations and global grand challenges (Ferraro, Etzion, & Gehman, 2015) demand continuous innovations in products, programs, business processes, and strategies. For example, digitalization is transforming business models from vertical industrial silos such as consumer goods, materials, or financials to horizontal platforms that orchestrate networks, create technologies, and provide services (think Amazon, Alibaba). New markets and technologies emerge unpredictably but will produce major economic and social changes. Emerging economies more directly face grand challenge complexities of poverty, water scarcity, inequality, and climate changes. Innovations in emerging economy organizations are also very complex, since they often include innovations in sales, distribution, and business models along with rigorous product design and development processes.

Atmospheric deposition versus rock weathering in the control of streamwater chemistry in a tropical rain-forest catchment in Malaysian Borneo

2014 ◽  
Vol 30 (5) ◽  
pp. 481-492 ◽  
Author(s):  
Naoyuki Yamashita ◽  
Hiroyuki Sase ◽  
Ryo Kobayashi ◽  
Kok-Peng Leong ◽  
Jamil Mohd Hanapi ◽  
...  
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Chemical Weathering ◽  
Major Ions ◽  
Water Discharge ◽  
Base Cations ◽  
Base Cation ◽  
Ion Fluxes ◽  
Small Catchment ◽  
Streamwater Chemistry

Abstract:Uncertainty about the H+ buffering capacity in tropical rain forest limits our ability to predict the future effect of anthropogenic deposition on the streamwater chemistry. Export of major ions to the stream and the ion-fluxes via rainfall, throughfall, litter-leachate and soil-water pathways were observed to examine the source of streamwater nutrients in a small catchment in Sabah, Malaysia. The streamwater and the ion-fluxes were measured for 3.75 and 2 y, respectively, by collecting water twice a month and setting ion-exchange-resin columns. Streamwater pH ranged from 6.5 to 7.6 and was not sensitive to water discharge controlling base cations. The NO3−-N, Ca2+ and Mg2+ fluxes were low in atmospheric depositions (0.6, 0.5 and 0.3 kg ha−1 y−1, respectively) and markedly increased in the litter layer. The NO3−-N flux decreased drastically from subsoil (70 kg ha−1 y−1) to the stream (1.4 kg ha−1 y−1) whereas the Ca2+ and Mg2+ fluxes were not different between subsoil (38 and 18 kg ha−1 y−1) and stream (30 and 15 kg ha−1 y−1). Neutral pH in tropical streams was mainly due to the base cation leaching with deep chemical weathering in deeper strata, and a rapid decrease in NO3− leaching from the subsoil to the stream.

scholarly journals 494 PB 172 Use of Thin-Beam Load Cells as Pot Lysimeters in Greenhouse Studies

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 502b-502
Author(s):  
Mark V. Yelanich ◽  
James E. Faust ◽  
Royal D. Heins ◽  
John A Biernbaum
Keyword(s):  
Linear Function ◽  
Electrical Signal ◽  
Effect Of Temperature ◽  
Sensor Output ◽  
Mass Measurements ◽  
Thin Beam ◽  
Air Temperatures ◽  
Load Cells ◽  
Continuous Mass ◽  
Over Time

The measurement of evaporation and transpiration from container-grown crops is labor intensive and expensive if measurements are made by periodic weighing of the plants with electronic scales. Thin-beam load cells (LCL-816G, Omega Engineering) measured with a datalogger provides a method of making continuous mass measurements over time. Four load cells were tested to determine the feasibility for use in greenhouse studies. The sensors were calibrated to an electronic scale at a range of air temperatures. The electrical signal (μV) was a linear function of mass from 0 to 816 g. The change in mass per change in electrical signal (i.e. the slope) was the same for all four load cells (1.26 g ·μV-1), however the absolute electrical signal (the intercept) was unique for each sensor (-246 to + 101 g). The effect of temperature on sensor output was unique for each sensor in terms of both the magnitude and direction of change. A two-point calibration of mass performed at a range of temperatures is required to properly use thin-beam load cells to continuously measure evapotranspiration of container-grown crops.

High Andean Soil Landscapes Shaped by Interactions between Geomorphology, Vegetation, and Hydrology

2020 ◽  
Author(s):  
Veerle Vanacker ◽  
Armando Molina ◽  
Santiago Zhiminaicela ◽  
Marife Corre ◽  
Edzo Veldkamp
Keyword(s):  
Chemical Weathering ◽  
Soil Surface ◽  
Terrestrial Ecosystems ◽  
Base Cation ◽  
Parent Material ◽  
Subsurface Water ◽  
Native Forest ◽  
Good Opportunity ◽  
Vegetation Communities ◽  
Environmental Controls

<p>Physical and chemical weathering processes fulfil a crucial function in the biogeochemistry of terrestrial ecosystems. Rock‐derived weathering products provide essential plant nutrients, and regulate the chemical composition of soil, surface, and groundwater. The rate and extent of chemical weathering are influenced by the combined effects of climate, parent material, topography, and vegetation, and ultimately determine the mineral composition and element ratios of soil material. Understanding the spatial variation of rock‐derived weathering products across heterogeneous landscapes not only relies on knowledge of the environmental controls but also of their interactions.</p><p>High Andean tropical ecosystems provide a good opportunity to study the association between chemical weathering, local topography and vegetation patterns: the climate, parent material and soil age can be held constant at the landscape scale, while the vegetation and slope morphology can vary greatly from the hilltops to the valley bottoms. In this study, we selected 10 soil toposequences on andesitic flows: 5 under tussock grasses, 3 under cushion forming plants and 2 under native forest. A marginally significant increase in base cation depletion is observed along topographic gradients that can be associated with physical transport of weathered soil particles downslope or subsurface water fluxes. Beyond the hillslope-scale topographic control on chemical weathering extent, we observed highly significant differences in chemical weathering extent between vegetation communities with total mass losses in forest soils being respectively 19% and 22% higher than in grasslands and cushion forming plants. Although biotic factors can play a role in creating the observed patterns in soil development, the vegetation communities can also hint to the existence of hillslope micro-topography and subsurface hydrological patterns that are challenging to map in the field.</p>

Soil temperatures and stability of ice-cemented ground in the McMurdo Dry Valleys, Antarctica

1998 ◽  
Vol 10 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Christopher P. McKay ◽  
Michael T. Mellon ◽  
E. Imre Friedmann
Keyword(s):  
Water Vapour ◽  
Temperature Measurements ◽  
Dry Valleys ◽  
Frost Point ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Net Flux ◽  
The Mean ◽  
Long Timescales ◽  
Over Time

Year-round temperature measurements at 1600 m elevation during 1994 in the Asgard Range Antarctica, indicate that the mean annual frost point of the ice-cemented ground, 25 cm below the surface, is −21.7 ± 0.2°C and the mean annual frost point of the atmosphere is −27.5 ± 1.0°C. The corresponding mean annual temperatures are −24.9°C and −23.3°C. These results imply that there is a net flux of water vapour from the ice to the atmosphere resulting in a recession of the ice-cemented ground by about 0.4–0.6 mm yr1. The level of the ice-cemented permafrost is about 12 cm below the level of dry permafrost. The summer air temperatures would have to increase about 7°C for thawing temperatures to just reach the top of the subsurface ice. Either subsurface ice at this location is evaporating over time or there are sporadic processes that recharge the ice and maintain equilibrium over long timescales.

scholarly journals Riparian zone controls on base cation concentrations in boreal streams

2013 ◽  
Vol 10 (1) ◽  
pp. 739-785 ◽  
Author(s):  
J. L. J. Ledesma ◽  
T. Grabs ◽  
M. N. Futter ◽  
K. H. Bishop ◽  
H. Laudon ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Riparian Zone ◽  
Stream Water ◽  
Temporal Stability ◽  
Base Cation ◽  
Forest Harvesting ◽  
Riparian Zones ◽  
Negative Consequences ◽  
Integration Model ◽  
Groundwater Levels

Abstract. Forest riparian zones are a major in control of surface water quality. Base cation (BC) concentrations, fluxes, and cycling in the riparian zone merit attention because of increasing concern of negative consequences for re-acidification of surface waters from future climate and forest harvesting scenarios. We present a two-year study of BC and silica (Si) flow-weighted concentrations from 13 riparian zones and 14 streams in a boreal catchment in northern Sweden. The Riparian Flow-Concentration Integration Model (RIM) was used to estimate riparian zone flow-weighted concentrations and tested to predict the stream flow-weighted concentrations. Spatial variation in BC and Si concentrations as well as in flow-weighted concentrations was related to differences in Quaternary deposits, with the largest contribution from lower lying silty sediments and the lowest contribution from wetland areas higher up in the catchment. Temporal stability in the concentrations of most elements, a remarkably stable Mg / Ca ratio in the soil water and a homogeneous mineralogy suggest that the stable patterns found in the riparian zones are a result of distinct mineralogical upslope groundwater signals integrating the chemical signals of biological and chemical weathering. Stream water Mg / Ca ratio indicates that the signal is subsequently maintained in the streams. RIM gave good predictions of Ca, Mg, and Na flow-weighted concentrations in headwater streams. The difficulty in modelling K and Si suggests a stronger biogeochemical influence on these elements. The observed chemical dilution effect with flow in the streams was related to variation in groundwater levels and element concentration profiles in the riparian zones. This study provides a first step toward specific investigations of the vulnerability of riparian zones to changes induced by forest management or climate change, with focus on BC or other compounds.

Effect of environmental temperature on body temperature and metabolic heat production in a heterothermic rodent,Spermophilus tereticaudus

2002 ◽  
Vol 205 (14) ◽  
pp. 2099-2105 ◽  
Author(s):  
K. Mark Wooden ◽  
Glenn E. Walsberg
Keyword(s):  
Body Temperature ◽  
Ground Squirrel ◽  
Environmental Temperature ◽  
Body Temperatures ◽  
Metabolic Heat ◽  
Thermoneutral Zone ◽  
Air Temperatures ◽  
The Mean ◽  
Maximum Body ◽  
Over Time

SUMMARYThis study quantifies the thermoregulatory ability and energetics of a mammal, the round-tailed ground squirrel Spermophilus tereticaudus,that can relax thermoregulatory limits without becoming inactive. We measured body temperature and metabolic rate in animals exposed for short periods (1 h)to air temperatures ranging from 10 to 45 °C and for long periods (8 h) to air temperatures ranging from 10 to 30 °C. Within 45 min of exposure to air temperatures ranging from 10 to 45 °C, the mean body temperatures of alert and responsive animals ranged from 32.1 °C(Tair=10 °C) to 40.4 °C(Tair=45 °C). This thermolability provided significant energetic savings below the thermoneutral zone, ranging from 0.63 W (18 %) at 10 °C to 0.43 W (43 %) at 30 °C. When exposed for 8 h to air temperatures between 10 and 30 °C, animals varied their body temperature significantly over time. At all air temperatures, the lowest body temperature(maintained for at least 1 h) was 31.2 °C. The highest body temperatures(maintained for at least 1 h) were 33.6 °C at 10 °C, 35.3 °C at 20°C and 36.3 °C at 30 °C. The energetic savings realized by maintaining the minimum rather than the maximum body temperature was 0.80 W(25 %) at 10 °C, 0.71 W (33 %) at 20 °C and 0.40 W (47 %) at 30°C. This study demonstrates in several ways the ability of this species to adjust energy expenditure through heterothermy.

scholarly journals Exploring the climatic impact of the continental vegetation on the Mezosoic atmospheric CO<sub>2</sub> and climate history

2009 ◽  
Vol 5 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Y. Donnadieu ◽  
Y. Goddéris ◽  
N. Bouttes
Keyword(s):  
Chemical Weathering ◽  
Water Cycle ◽  
Atmospheric Co2 ◽  
Explicit Calculation ◽  
Climatic Impact ◽  
Climate History ◽  
Albedo Change ◽  
Climatic History ◽  
The Impact

Abstract. In this contribution, we continue our exploration of the factors defining the Mesozoic climatic history. We improve the Earth system model GEOCLIM designed for long term climate and geochemical reconstructions by adding the explicit calculation of the biome dynamics using the LPJ model. The coupled GEOCLIM-LPJ model thus allows the simultaneous calculation of the climate with a 2-D spatial resolution, the coeval atmospheric CO2, and the continental biome distribution. We found that accounting for the climatic role of the continental vegetation dynamics (albedo change, water cycle and surface roughness modulations) strongly affects the reconstructed geological climate. Indeed the calculated partial pressure of atmospheric CO2 over the Mesozoic is twice the value calculated when assuming a uniform constant vegetation. This increase in CO2 is triggered by a global cooling of the continents, itself triggered by a general increase in continental albedo owing to the development of desertic surfaces. This cooling reduces the CO2 consumption through silicate weathering, and hence results in a compensating increase in the atmospheric CO2 pressure. This study demonstrates that the impact of land plants on climate and hence on atmospheric CO2 is as important as their geochemical effect through the enhancement of chemical weathering of the continental surface. Our GEOCLIM-LPJ simulations also define a climatic baseline for the Mesozoic, around which exceptionally cool and warm events can be identified.

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