scholarly journals Storm-triggered landslides in the Peruvian Andes and implications for topography, carbon cycles, and biodiversity

2016 ◽  
Vol 4 (1) ◽  
pp. 47-70 ◽  
Author(s):  
K. E. Clark ◽  
A. J. West ◽  
R. G. Hilton ◽  
G. P. Asner ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Amazon Basin ◽  
Low Frequency ◽  
Mountain Forest ◽  
Ecological Disturbance ◽  
Peruvian Andes ◽  
Landslide Occurrence ◽  
Carbon Cycles ◽  
Organic Carbon Flux ◽  
Frequency Relationship

Abstract. In this study, we assess the geomorphic role of a rare, large-magnitude landslide-triggering event and consider its effect on mountain forest ecosystems and the erosion of organic carbon in an Andean river catchment. Proximal triggers such as large rain storms are known to cause large numbers of landslides, but the relative effects of such low-frequency, high-magnitude events are not well known in the context of more regular, smaller events. We develop a 25-year duration, annual-resolution landslide inventory by mapping landslide occurrence in the Kosñipata Valley, Peru, from 1988 to 2012 using Landsat, QuickBird, and WorldView satellite images. Catchment-wide landslide rates were high, averaging 0.076 % yr−1 by area. As a result, landslides on average completely turn over hillslopes every  ∼  1320 years, although our data suggest that landslide occurrence varies spatially and temporally, such that turnover times are likely to be non-uniform. In total, landslides stripped 26 ± 4 tC km−2 yr−1 of organic carbon from soil (80 %) and vegetation (20 %) during the study period. A single rain storm in March 2010 accounted for 27 % of all landslide area observed during the 25-year study and accounted for 26 % of the landslide-associated organic carbon flux. An approximately linear magnitude–frequency relationship for annual landslide areas suggests that large storms contribute an equivalent landslide failure area to the sum of lower-frequency landslide events occurring over the same period. However, the spatial distribution of landslides associated with the 2010 storm is distinct. On the basis of precipitation statistics and landscape morphology, we hypothesise that focusing of storm-triggered landslide erosion at lower elevations in the Kosñipata catchment may be characteristic of longer-term patterns. These patterns may have implications for the source and composition of sediments and organic material supplied to river systems of the Amazon Basin, and, through focusing of regular ecological disturbance, for the species composition of forested ecosystems in the region.

scholarly journals Storm-triggered landslides in the Peruvian Andes and implications for topography, carbon cycles, and biodiversity

2015 ◽  
Vol 3 (3) ◽  
pp. 631-688 ◽  
Author(s):  
K. E. Clark ◽  
A. J. West ◽  
R. G. Hilton ◽  
G. P. Asner ◽  
C. A. Quesada ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Amazon Basin ◽  
Low Frequency ◽  
Mountain Forest ◽  
Ecological Disturbance ◽  
Peruvian Andes ◽  
Landslide Occurrence ◽  
Carbon Cycles ◽  
Landslide Event ◽  
Frequency Relationship

Abstract. In this study, we assess the geomorphic role of a rare, large-magnitude landslide event and consider the effect of this event on mountain forest ecosystems and the erosion of organic carbon in an Andean river catchment. Proximal triggers such as large rain storms are known to cause large numbers of landslides, but the relative effects of such low-frequency, high-magnitude events are not well known in the context of more regular, smaller events. We develop a 25 year duration, annual-resolution landslide inventory by mapping landslide occurrence in the Kosñipata Valley, Peru, from 1988 to 2012 using Landsat, Quickbird and Worldview satellite images. Catchment-wide landslide rates were high, at 0.076 % yr−1 by area, indicating landslides may completely turn over hillslopes every ~ 1320 years and strip 28 tC km−2 yr−1 of soil (73 %) and vegetation (27 %). A single rain storm in March 2010 accounted for 27 % of all landslide area observed during the 25 year study and removed 26 % of the organic carbon that was stripped from hillslopes by all landslides during the study. An approximately linear magnitude–frequency relationship for annual landslide areas suggests that large storms contribute an equivalent landslide failure area to the sum of smaller frequency landslides events occurring over the same period. However, the spatial distribution of landslides associated with the 2010 storm is distinct. On the basis of precipitation statistics and landscape morphology, we hypothesize that spatial focusing of storm-triggered landslide erosion at lower elevations in the Kosñipata catchment may be characteristic of longer-term patterns. These patterns may have implications for the source and composition of sediments and organic material supplied to river systems of the Amazon basin, and, through focusing of regular ecological disturbance, for the species composition of forested ecosystems in the region.

scholarly journals Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean

2009 ◽  
Vol 6 (1) ◽  
pp. 85-102 ◽  
Author(s):  
G. Fischer ◽  
G. Karakaş
Keyword(s):  
Organic Carbon ◽  
Atlantic Ocean ◽  
Sediment Trap ◽  
Carbon Flux ◽  
Coastal Upwelling ◽  
Production Systems ◽  
Deep Ocean ◽  
Biogeochemical Model ◽  
Carbonate Content ◽  
Organic Carbon Flux

Abstract. The flux of materials to the deep sea is dominated by larger, organic-rich particles with sinking rates varying between a few meters and several hundred meters per day. Mineral ballast may regulate the transfer of organic matter and other components by determining the sinking rates, e.g. via particle density. We calculated particle sinking rates from mass flux patterns and alkenone measurements applying the results of sediment trap experiments from the Atlantic Ocean. We have indication for higher particle sinking rates in carbonate-dominated production systems when considering both regional and seasonal data. During a summer coccolithophorid bloom in the Cape Blanc coastal upwelling off Mauritania, particle sinking rates reached almost 570 m per day, most probably due the fast sedimentation of densely packed zooplankton fecal pellets, which transport high amounts of organic carbon associated with coccoliths to the deep ocean despite rather low production. During the recurring winter-spring blooms off NW Africa and in opal-rich production systems of the Southern Ocean, sinking rates of larger particles, most probably diatom aggregates, showed a tendency to lower values. However, there is no straightforward relationship between carbonate content and particle sinking rates. This could be due to the unknown composition of carbonate and/or the influence of particle size and shape on sinking rates. It also remains noticeable that the highest sinking rates occurred in dust-rich ocean regions off NW Africa, but this issue deserves further detailed field and laboratory investigations. We obtained increasing sinking rates with depth. By using a seven-compartment biogeochemical model, it was shown that the deep ocean organic carbon flux at a mesotrophic sediment trap site off Cape Blanc can be captured fairly well using seasonal variable particle sinking rates. Our model provides a total organic carbon flux of 0.29 Tg per year down to 3000 m off the NW African upwelling region between 5 and 35° N. Simple parameterisations of remineralisation and sinking rates in such models, however, limit their capability in reproducing the flux variation in the water column.

scholarly journals Deforestation in Amazonia impacts riverine carbon dynamics

2016 ◽  
Vol 7 (4) ◽  
pp. 953-968 ◽  
Author(s):  
Fanny Langerwisch ◽  
Ariane Walz ◽  
Anja Rammig ◽  
Britta Tietjen ◽  
Kirsten Thonicke ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Atlantic Ocean ◽  
Amazon Basin ◽  
Inorganic Carbon ◽  
Carbon Dynamics ◽  
Model System ◽  
Atmospheric Co2 ◽  
Terrestrial Productivity

Abstract. Fluxes of organic and inorganic carbon within the Amazon basin are considerably controlled by annual flooding, which triggers the export of terrigenous organic material to the river and ultimately to the Atlantic Ocean. The amount of carbon imported to the river and the further conversion, transport and export of it depend on temperature, atmospheric CO2, terrestrial productivity and carbon storage, as well as discharge. Both terrestrial productivity and discharge are influenced by climate and land use change. The coupled LPJmL and RivCM model system (Langerwisch et al., 2016) has been applied to assess the combined impacts of climate and land use change on the Amazon riverine carbon dynamics. Vegetation dynamics (in LPJmL) as well as export and conversion of terrigenous carbon to and within the river (RivCM) are included. The model system has been applied for the years 1901 to 2099 under two deforestation scenarios and with climate forcing of three SRES emission scenarios, each for five climate models. We find that high deforestation (business-as-usual scenario) will strongly decrease (locally by up to 90 %) riverine particulate and dissolved organic carbon amount until the end of the current century. At the same time, increase in discharge leaves net carbon transport during the first decades of the century roughly unchanged only if a sufficient area is still forested. After 2050 the amount of transported carbon will decrease drastically. In contrast to that, increased temperature and atmospheric CO2 concentration determine the amount of riverine inorganic carbon stored in the Amazon basin. Higher atmospheric CO2 concentrations increase riverine inorganic carbon amount by up to 20 % (SRES A2). The changes in riverine carbon fluxes have direct effects on carbon export, either to the atmosphere via outgassing or to the Atlantic Ocean via discharge. The outgassed carbon will increase slightly in the Amazon basin, but can be regionally reduced by up to 60 % due to deforestation. The discharge of organic carbon to the ocean will be reduced by about 40 % under the most severe deforestation and climate change scenario. These changes would have local and regional consequences on the carbon balance and habitat characteristics in the Amazon basin itself as well as in the adjacent Atlantic Ocean.

Near-maximal voluntary hyperpnea and ventilatory muscle function

1984 ◽  
Vol 57 (6) ◽  
pp. 1742-1748 ◽  
Author(s):  
T. R. Bai ◽  
B. J. Rabinovitch ◽  
R. L. Pardy
Keyword(s):  
Muscle Function ◽  
Low Frequency ◽  
Normal Subjects ◽  
Pressure Time ◽  
Before And After ◽  
Expiratory Muscles ◽  
Four Levels ◽  
Frequency Relationship ◽  
Low Frequency Power ◽  
Relationship Of

Because of its potential relevance to heavy exercise we studied the ventilatory muscle function of five normal subjects before, during, and after shortterm near-maximal voluntary normocapnic hyperpnea. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made at four levels of ventilation: 76, 79, and 86% maximal voluntary ventilation (MVV) and at MVV. Measurements of pleural and abdominal pressures and diaphragm electromyogram (EMG) during hyperpnea and of maximum respiratory pressures before and after hyperpnea were made. The pressure-stimulation frequency relationship of the diaphragm obtained by unilateral transcutaneous phrenic nerve stimulation was studied in two subjects before and after hyperpnea. Decreases in maximal inspiratory (PImax) and transdiaphragmatic (Pdimax) strength were recorded posthyperpnea at 76 and 79% MVV. Decreases in the pressure-frequency curves of the diaphragm and the ratio of high-to-low frequency power of the diaphragm EMG occurred in association with decreases in Pdimax. Analysis of the pressure-time product (P X dt) for the inspiratory and expiratory muscles individually indicated the increasing contribution of expiratory muscle force to the attainment of higher levels of ventilation. Demonstrable ventilatory muscle fatigue may limit endurance at high levels of ventilation.

scholarly journals Climate impacts on tree growth in a Neotropical high mountain forest of the Peruvian Andes

2020 ◽  
Vol 13 (1) ◽  
pp. 194-201
Author(s):  
C Rodríguez-Morata ◽  
J Madrigal-González ◽  
M Stoffel ◽  
JA Ballesteros-Cánovas
Keyword(s):  
Tree Growth ◽  
Climate Impacts ◽  
Mountain Forest ◽  
High Mountain ◽  
Peruvian Andes

scholarly journals The Glaciochemistry of Snow-Pits from Quelccaya Ice Cap, Peru, 1982

1985 ◽  
Vol 7 ◽  
pp. 84-88 ◽  
Author(s):  
W. Berry Lyons ◽  
A. Paul Mayewski ◽  
Lonnie G. Thompson ◽  
Boyd Allen
Keyword(s):  
Amazon Basin ◽  
Atomic Absorption Spectrophotometry ◽  
High Elevation ◽  
Common Source ◽  
Gaseous Emissions ◽  
Polar Ice ◽  
Peruvian Andes ◽  
Reactive Iron ◽  
Ice Cap ◽  
Quelccaya Ice Cap

We present glaciochemical data from a pilot study of two snow-pits from Quelccaya ice cap, Peruvian Andes. These are the first samples to be analyzed from Quelccaya for nitrate and sulfate by ion chromatography (IC), for nitrate-plus-nitrite, reactive silicate and reactive iron by colorimetry, and for sodium by atomic absorption spectrophotometry. The 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations.Reactive iron, reactive silicate and sodium, and the profiles of >0.63μm microparticles from Thompson and others (1984) are coincident, suggesting that transport and deposition into this area of each species are controlled by similar processes. The common source is probably local, resulting from crustal weathering. In general, the reactive silicate values are lower than those observed in other alpine glacier ice. The highest sulfate and nitrate values were observed in the upper few centimeters of the snow-pit. Most of the sulfate concentrations were less than 3 μM and are similar to values obtained for fresh surface snows from Bolivia (Stallard and Edmond 1981). Since biological gaseous emissions are thought to be the major source of sulfur and nitrogen to the atmosphere over the Amazon basin, the sulfate and nitrate fluctuations may be due to seasonal biological input and/or seasonal shifts in wind direction bringing material to Quelccaya.With only one exception, the colorimetric nitrate-plus-nitrite data were higher than the IC nitrate data. Unfortunately, the IC analyses were conducted 81 d after the colorimetric analyses. The difference between the two data sets could be attributable to the following: (1) the colorimetric technique may yield erroneously high results as suggested for polar ice by Herron (1982), (2) the IC technique yields erroneously low results due, in part, to the possible exclusion of nitrite concentrations, and/or (3) nitrite was lost via biological removal during the 81 d period before the IC analyses. If the IC data are correct, the mean nitrate value is 0.4μΜ (n = 29). This value is similar to those reported from pre-industrial aged polar ice (Herron 1982). If the colorimetric mean value (1.1 μM) is correct, it is similar to colorimetrically determined values from other high-elevation alpine ice (Lyons and Mayewski 1983).

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