Patterns And Controls On Methane And Carbon Dioxide Fluxes On The Arctic Coastal Plain Alaska PDF Download
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Author | : Donatella Zona |
Publisher | : |
Total Pages | : 198 |
Release | : 2009 |
Genre | : Atmospheric carbon dioxide |
ISBN | : |
Download Patterns and Controls on Methane and Carbon Dioxide Fluxes on the Arctic Coastal Plain, Alaska Book in PDF, ePub and Kindle
My research focuses on the patterns and controls of CO2 and CH4 fluxes in vegetated drained lake basins on the Arctic Coastal Plain in northern Alaska. These land features account for the majority of the landscape in the Arctic Coastal Plain, but have never been systematically investigated with respect to their impact on trace gas fluxes in the global carbon budget. In the first part of my research I focused on the impacts of water table change on CO2 and CH4 fluxes in a vegetated drained lake basin, where the water table was manipulated. I showed that the water table drop below the surface may not decrease CH4 emissions if a simultaneous increase in thaw depth increases the soil volume available for methanogenesis. On the other hand, an increase in water table above the surface could increase the diffusive resistance to CH4 release and decrease its emission. The impact of water table increase on CO2 was also surprising. Contrary to the common prediction, I demonstrated that increasing the water table level can increase CO2 injection into the atmosphere. This CO2 loss from the ecosystem is likely due to an increase in respiration, for the increase soil volume in the flood area, and decrease in light at the level of the photosynthetic organs. In the last part of my research, I study the carbon dynamics of a number of vegetated drained lake basins, which drained from 50 to 2000 years ago, in the Arctic Coastal Plain. I characterized 12 vegetated drained lake basins in terms of net ecosystem exchange (NEE), ecosystem respiration (ER) and gross primary production (GPP), and investigated the seasonal patterns and environmental controls on CO2 fluxes. The comparison of the seasonal CO2 fluxes in vegetated drained lake basins of different age allowed me to test the validity of the traditional view that net primary production decreases with ecosystem maturity . I showed that ecosystems thousands of years old (i.e. old vegetated drained lake basins are still a CO2 sink in the global carbon budget.
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Total Pages | : 9 |
Release | : 2015 |
Genre | : |
ISBN | : |
Download Seasonal and Intra-annual Controls on CO2 Flux in Arctic Alaska Book in PDF, ePub and Kindle
In order to advance the understanding of the patterns and controls on the carbon budget in the Arctic region, San Diego State University has maintained eddy covariance flux towers at three sites in Arctic Alaska, starting in 1997.
Author | : Walter C. Oechel |
Publisher | : |
Total Pages | : 31 |
Release | : 1994* |
Genre | : Atmospheric carbon dioxide |
ISBN | : |
Download The Pattern Of, and the Controls on , Net CO2 Flux Along a Latitudinal Transect on the North Slope of Alaska Book in PDF, ePub and Kindle
Author | : |
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Total Pages | : |
Release | : 2002 |
Genre | : |
ISBN | : |
Download Patterns and Controls of Temporal Variation in CO2 Sequestration and Loss in Arctic Ecosystems Book in PDF, ePub and Kindle
Determine seasonal and interannual patterns of net ecosystem CO2 flux from wet coastal and moist tussock tundra.
Author | : Sivakiruthika Natchimuthu |
Publisher | : Linköping University Electronic Press |
Total Pages | : 56 |
Release | : 2016-09-05 |
Genre | : |
ISBN | : 917685812X |
Download Freshwater methane and carbon dioxide fluxes Book in PDF, ePub and Kindle
Freshwater bodies such as lakes and streams release the greenhouse gases methane (CH4) and carbon dioxide (CO2) into the atmosphere. Global freshwater CH4 and CO2 emissions have been estimated to be of a similar magnitude to the global land or ocean carbon sink, and are thus significant components of global carbon budgets. However, the data supporting global estimates frequently lacks information regarding spatial and temporal variability and are thus highly inaccurate. In this thesis, detailed studies of the spatio-temporal variability of CH4 and CO2 fluxes were conducted in the open water areas of lakes and streams within a whole catchment in Sweden. One aim was also to evaluate the importance of spatio-temporal variability in lake and stream fluxes when making whole catchment aquatic or large scale assessments. Apart from the expected large spatio-temporal variability in lake fluxes, interactions between spatial and temporal variability in CH4 fluxes were found. Shallow lakes and shallow areas of lakes were observed to emit more CH4 as compared to their deeper counterparts. This spatial variability interacted with the temporal variability driven by an exponential temperature response of the fluxes, which meant that shallow waters were more sensitive to warming than deeper ones. Such interactions may be important for climate feedbacks. Surface water CO2 in lakes showed significant spatio-temporal variability and, when considering variability in both space and time, CO2 fluxes were largely controlled by concentrations, rather than gas transfer velocities. Stream fluxes were also highly variable in space and time and in particular, stream CH4 fluxes were surprisingly large and more variable than CO2 fluxes. Fluxes were large from stream areas with steep slopes and periods of high discharge which occupied a small fraction of the total stream area and the total measurement period, respectively, and a failure to account for these spatially distinct or episodic high fluxes could lead to underestimates. The total aquatic fluxes from the whole catchment were estimated by combining the measurements in open waters of lakes and streams. Using our data, recommendations on improved study designs for representative measurements in lakes and streams were provided for future studies. Thus, this thesis presents findings relating to flux regulation in lakes and streams, and urges forthcoming studies to better consider spatio-temporal variability so as to achieve unbiased large-scale estimates.
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Total Pages | : |
Release | : 1994 |
Genre | : Community life |
ISBN | : |
Download Newcomers' Guide Collection Book in PDF, ePub and Kindle
Issues of the Newcomers' Guide Kalamazoo-Battle Creek, published in September by the Valentine Group, Kalamazoo, Michigan, 1994-2008.
Author | : |
Publisher | : |
Total Pages | : 60 |
Release | : 1993 |
Genre | : Arctic Regions |
ISBN | : |
Download Arctic System Science Book in PDF, ePub and Kindle
Author | : Arthur H. Lachenbruch |
Publisher | : Geological Society of America |
Total Pages | : 81 |
Release | : 1962 |
Genre | : Frozen ground |
ISBN | : 0813720702 |
Download Mechanics of Thermal Contraction Cracks and Ice-Wedge Polygons in Permafrost Book in PDF, ePub and Kindle
Author | : Zhiliang Zhu |
Publisher | : Geological Survey Reston |
Total Pages | : |
Release | : 2016-08-01 |
Genre | : |
ISBN | : 9781411340381 |
Download Baseline and Projected Future Carbon Storage and Greenhouse-Gas Fluxes in Ecosystems of Alaska Book in PDF, ePub and Kindle
Author | : Branimir Trifunovic |
Publisher | : |
Total Pages | : 47 |
Release | : 2020 |
Genre | : |
ISBN | : 9781392818831 |
Download Carbon Dioxide and Methane Emissions from a Temperate Salt Marsh Tidal Creek Book in PDF, ePub and Kindle
Coastal salt marshes store large amounts of carbon but the magnitude and patterns of greenhouse gas (GHGs; including CO2 and CH4) fluxes are unclear. Information about GHG fluxes from these ecosystems mainly comes from studies of sediments or at the ecosystem-scale (using eddy covariance), but fluxes from tidal creeks are currently unknown. We measured GHG concentrations in water, water quality, meteorology, sediment CO2 efflux, ecosystem-scale GHG fluxes, and plant phenology; all at half-hour time-steps over one year. Manual creek GHG flux measurements were used to parameterize a model of water-to-atmosphere GHG fluxes. The creek was a source of GHGs to the atmosphere where tidal patterns rather than water temperature controlled diel variability. Dissolved oxygen and wind speed were inversely correlated with creek CH4 efflux. Despite lacking a seasonal pattern, creek CO2 efflux was correlated with drivers such as turbidity across phenological phases. Overall, night-time creek CO2 efflux (3.6 ℗ł 0.63 ℗æmol/m2/s) was over two times higher than night-time marsh sediment CO2 efflux (1.5 ℗ł 1.23 ℗æmol/m2/s). Creek CH4 efflux (17.5 ℗ł 6.9 nmol/m2/s) was four times lower than ecosystem-scale CH4 fluxes (68.1 ℗ł 52.3 nmol/m2/s) across the year. These results suggest that salt marsh tidal creeks are potential hotspots for CO2 emissions and (because they are supersaturated with CH4; up to >6000 ℗æmol/mol) could contribute to lateral transport of CH4 to the coastal ocean. This study provides insights for modelling GHG efflux from tidal creeks and suggests that changes in tide stage overshadows water temperature in determining magnitudes of fluxes.