Download or read book Paleoreconstruction of Particulate Organic Carbon Inputs to the High Arctic Colville River Delta Beaufort Sea Alaska written by Kathryn Schreiner and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High Arctic permafrosted soils represent a massive sink in the global carbon cycle, accounting for twice as much carbon as what is currently stored as carbon dioxide in the atmosphere. However, with current warming trends this sink is in danger of thawing and potentially releasing large amounts of carbon as both carbon dioxide and methane into the atmosphere. It is difficult to make predictions about the future of this sink without knowing how it has reacted to past temperature and climate changes. This dissertation summarizes the results of the first study to look at long term, fine scale organic carbon delivery by the high-Arctic Colville River into Simpson̕ s Lagoon in the near-shore Beaufort Sea. Modern delivery of organic carbon to the Lagoon was determined to come from a variety of sources through the use of a three end-member mixing model and sediment biomarker concentrations. These sources include the Colville River in the western area of the Lagoon near the river mouth, marine sources in areas of the Lagoon without protective barrier islands, and coastal erosional sources and the Mackenzie River in the eastern area of the Lagoon. Downcore organic carbon delivery was measured on two cores in the Lagoon, one taken near the mouth of the Colville River (spans about 1800 years of history) and one taken on the eastern end of the Lagoon (spans about 600 years of history). Bulk organic parameters and biomarkers were measured in both cores and analyzed with Principle Component Analysis to determine long-term trends in organic carbon delivery. It was shown that at various times in the past, highly degraded organic carbon inputs of what is likely soil and peat carbon were delivered to the Lagoon. At other times, inputs of fresher, non-degraded, terrestrially-derived organic carbon inputs of what are likely higher amounts of plant and vegetative material was delivered to the Lagoon. Inputs of degraded soil carbon were also shown to correspond to higher temperatures on the North Slope of Alaska, likely indicating that warmer temperatures lead to a thawing of permafrost and in turn organic carbon mobilization to the coastal Beaufort Sea. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149229

Download or read book Reconstruction of a High resolution Late Holocene Arctic Paleoclimate Record from Colville River Delta Sediments written by and published by . This book was released on 2013 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was partially supported by the Sandia National Laboratories, 'Laboratory Directed Research and Development' (LDRD) fellowship program in conjunction with Texas A & M University (TAMU). The research described herein is the work of Kathryn M. Schreiner ('Katie') and her advisor, Thomas S. Bianchi and represents a concise description of Katie's dissertation that was submitted to the TAMU Office of Graduate Studies in May 2013 in partial fulfillment of her doctorate of philosophy degree. High Arctic permafrost soils contain a massive amount of organic carbon, accounting for twice as much carbon as what is currently stored as carbon dioxide in the atmosphere. However, with current warming trends this sink is in danger of thawing and potentially releasing large amounts of carbon as both carbon dioxide and methane into the atmosphere. It is difficult to make predictions about the future of this sink without knowing how it has reacted to past temperature and climate changes. This project investigated long term, fine scale particulate organic carbon (POC) delivery by the high-Arctic Colville River into Simpson's Lagoon in the near-shore Beaufort Sea. Modern POC was determined to be a mixture of three sources (riverine soils, coastal erosion, and marine). Downcore POC measurements were performed in a core close to the Colville River output and a core close to intense coastal erosion. Inputs of the three major sources were found to vary throughout the last two millennia, and in the Colville River core covary significantly with Alaskan temperature reconstructions.

Download or read book Distribution of Dissolved and Particulate Organic Carbon in Alaskan Polar Sub polar and Estuarine Waters written by Theodore C. Loder and published by . This book was released on 1971 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral thesis. Reports on the distribution and significance of particulate and dissolved organic carbon in six areas of Alaskan waters - Southeast Alaska, Cook Inlet, Kodiak Island shelf, southeast Bering Sea - Unimak Pass, Bering Strait - Chukchi Sea, and the Arctic Ocean. It was found that the values cannot be easily predicted from nutrient and hydrographic data, and must be determined specifically when needed.

Download or read book Lability of Dissolved Organic Carbon in Arctic Rivers on the North Slope of Alaska written by Breton B. Frazer and published by . This book was released on 2007 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rivers are an important pathway of organic carbon-mobilization in the arctic, and their influence is projected to grow as precipitation and soil temperatures increase in response to highlatitude warming. This study addresses the bioactivity of arctic riverine dissolved organic carbon (DOC) in three North Slope Alaskan rivers: the Kuparuk, the Colville, and the Sagavanirktok. While lability experiments have previously been conducted during late summer discharge on arctic rivers, none have analyzed the early hydrograph spring-melt peak DOC. During the summer of 2006, water samples were taken from significant periods of the hydrograph (upswing, peak, downswing, and quasi-stable summer) of the three rivers for DOC lability experiments. DOC from spring melt discharge proved to be highly labile and therefore dynamically different from summer DOC. Over a three-month sample incubation period, these samples lost up to 40 and 33 percent of their DOC (with and without added nutrients, respectively) while samples taken later in summer lost merely 9 and 5 percent. As spring melt contributes half of the total annual discharge and DOC flux of winter-freezing rivers, a significant portion of annual arctic DOC is labile and is therefore a large input of bioactive organic DOC to the Arctic Ocean carbon cycle.

Download or read book Submarine Permafrost On The Alaskan Continental Shelf written by Michael E. Vigdorchik and published by Routledge. This book was released on 2019-09-05 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the second in a series on arctic and alpine environments produced by Dr. Michael Vigdorchik at the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder. The first carried the title Arctic Pleistocene History and the Development of Submarine Permafrost. The complicated Arctic Basin development during the Pleistocene has been described in that book, including the paleoenvironmental problems posed by the isolation of the Arctic Basin during the Ice Ages. This sequel concerns the identification and estimation of the potential hazards posed by the arctic environment to petroleum exploration and development on the Alaskan continental shelf.

Download or read book Reconstructing Late Holocene Artctic Climate Change Using High Resolution Sediment Records from Simpson Lagoon Alaska and the Colville River Alluvial Valley written by Andrea Jo Miller Hanna and published by . This book was released on 2015 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arctic nearshore environments proximal to large rivers, like Simpson Lagoon, Alaska, potentially contain high-resolution sediment archives that can be utilized to reconstruct paleoclimate variability over the late Holocene. The ongoing, rapid environmental changes recently observed in the Arctic highlight the need for high-resolution records of pre-industrial climate change in this climatically sensitive region; such records are fundamental for understanding recent anthropogenic changes in the context of natural variability. This dissertation utilizes a suite of geochemical and sedimentological proxies in combination with age-constrained, shallow acoustic reflection data to demonstrate that these underutilized coastal sediment archives are capable of generating high-resolution paleoclimate records on par with other terrestrial climate archives (i.e. lake sediments, ice cores, tree rings) and provides the first ~1650-year long record of climate variability from the inner shelf of the Alaskan Beaufort Sea. An analysis of sedimentation patterns within Simpson Lagoon using CHIRP seismic data and radioisotope geochronology reveals that sediment infilling in Simpson Lagoon began ~3500 y BP, creating a primary depocenter with mm y−1 sediment accumulation in western Simpson Lagoon. The interbedded sediments suggest that major sediment reworking from ice processes, a common occurrence in Arctic shelf environments, does not disrupt the sediment archive contained within the lagoon. Quantitative reconstructions of surface air temperature are obtained using the brGDGT-derived MBT'/CBT paleothermometer. A comprehensive study of lagoon and river sediments and catchment soils demonstrate that brGDGTs are primarily soil-derived, and yield reconstructed temperatures consistent with instrumental summer temperature observations from Alaska's North Slope. Temperature reconstructions from Simpson Lagoon also show similarities with regional and pan-Arctic climate records over the last few millennia, with evidence of temperature departures correlative with noted climate events (i.e., Little Ice Age, Medieval Climate Anomaly). In addition, temporal variability in sediment sourcing to the lagoon, determined using a multi-proxy approach (i.e., granulometry, elemental analysis, clay mineralogy), broadly corresponds with temperature fluctuations, indicating relative increases in fluvial sediment discharge during colder intervals and decreased river discharge/increased coastal erosion during warmer periods. This paleoclimate variability may be driven by variations in solar output and/or shifts in the regional ocean-atmosphere circulation patterns (e.g., the Aleutian Low).

Download or read book Pliocene and Pleistocene Fossils from the Arctic Coast of Alaska and the Auriferous Beaches of Nome Norton Sound Alaska written by William Healey Dall and published by . This book was released on 1920 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluxes of Soil Organic Carbon from Eroding Permafrost Coasts Canadian Beaufort Sea written by Nicole J. Couture and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Oxford Handbook of the Prehistoric Arctic written by T. Max Friesen and published by Oxford University Press. This book was released on 2016-08-05 with total page 1001 pages. Available in PDF, EPUB and Kindle. Book excerpt: The North American Arctic was one of the last regions on Earth to be settled by humans, due to its extreme climate, limited range of resources, and remoteness from populated areas. Despite these factors, it holds a complex and lengthy history relating to Inuit, Iñupiat, Inuvialuit, Yup'ik and Aleut peoples and their ancestors. The artifacts, dwellings, and food remains of these ancient peoples are remarkably well-preserved due to cold temperatures and permafrost, allowing archaeologists to reconstruct their lifeways with great accuracy. Furthermore, the combination of modern Elders' traditional knowledge with the region's high resolution ethnographic record allows past peoples' lives to be reconstructed to a level simply not possible elsewhere. Combined, these factors yield an archaeological record of global significance--the Arctic provides ideal case studies relating to issues as diverse as the impacts of climate change on human societies, the complex process of interaction between indigenous peoples and Europeans, and the dynamic relationships between environment, economy, social organization, and ideology in hunter-gatherer societies. In the The Oxford Handbook of the Prehistoric Arctic, each arctic cultural tradition is described in detail, with up-to-date coverage of recent interpretations of all aspects of their lifeways. Additional chapters cover broad themes applicable to the full range of arctic cultures, such as trade, stone tool technology, ancient DNA research, and the relationship between archaeology and modern arctic communities. The resulting volume, written by the region's leading researchers, contains by far the most comprehensive coverage of arctic archaeology ever assembled.

Download or read book The Distribution Transport and Cycling of Dissolved and Particulate Organic Carbon in the Potomac and Anacostia Rivers in the Greater Washington Area written by Michael A. Champ and published by . This book was released on 1979 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved and Particulate Organic Carbon in Some Colorado Waters with References written by and published by . This book was released on 1971 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particulate Organic Carbon Variability in the Subarctic Pacific Based on Transmissometer Data written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Total Organic Carbon and Rock eval Pyrolysis Data of Cutting from the Following Alaska Northslope Wells written by Alaska Geologic Materials Center and published by . This book was released on 2000 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Paleoenvironmental Analyses of an Organic Deposit from an Erosional Landscape Remnant Arctic Coastal Plain of Alaska written by and published by . This book was released on 2005 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dominant landscape process on the Arctic Coastal Plain of northern Alaska is the formation and drainage of thaw lakes. Lakes and drained thaw lake basins account for approximately 75% of the modern surface expression of the Barrow Peninsula. The thaw lake cycle usually obliterates lacustrine or peat sediments from previous cycles which could otherwise be used for paleoecological reconstruction of long-term landscape and vegetation changes. Several possible erosional remnants of a former topographic surface that predates the formation of the thaw lakes have been tentatively identified. These remnants are characterized by a higher elevation, a thick organic layer with very high ground ice content in the upper permafrost, and a plant community somewhat atypical of the region. Ten soil cores were collected from one site, and one core was intensively sampled for soil organic carbon content, pollen analysis, and 14C dating. The lowest level of the organic sediments represents the earliest phase of plant growth and dates to ca. 9000 cal BP. Palynological evidence indicates the presence of mesic shrub tundra (including sedge, birch, willow, and heath vegetation); and microfossil indicators point to wetter eutrophic conditions during this period. Carbon accumulation was rapid due to high net primary productivity in a relatively nutrient-rich environment. These results are interpreted as the local response to ameliorating climate during the early Holocene. The middle Holocene portion of the record contains an unconformity, indicating that between 8200 and 4200 cal BP sediments were eroded from the site, presumably in response to wind activity during a drier period centered around 4500 cal BP. The modern vegetation community of the erosional remnant was established after 4200 cal BP, and peat growth resumed. During the late Holocene, carbon accumulation rates were greatly reduced in response to the combined effects of declining productivity associated with climatic cooling, and increased nutrient stress as paludification and permafrost aggradation sequestered mineral nutrients.

Download or read book Biomarker and Carbon Isotope Constraints 13C 14C delta 13 C Delta 14 C on Sources and Cycling of Particulate Organic Matter Discharged by Large Siberian Rivers Draining Permafrost Areas written by Maria Winterfeld and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Primary Productivity and Biogeochemical Carbon Cycling in the Beaufort and Chukchi Seas Arctic Ocean written by Molly Alyse Palmer and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Arctic Ocean has undergone unprecedented changes in sea ice extent and thickness in recent years, including record-setting sea ice minimums in 2007 and 2012. These changes are predicted to affect Arctic marine primary productivity (the photosynthetic fixation of carbon dioxide by tiny algae called phytoplankton) because the timing and intensity of the summer phytoplankton bloom are strongly controlled by the dynamics of sea ice and water column stabilization. Satellite-based estimates indicate that primary production in ice-free waters has increased dramatically over the last few decades as a result of the increases in open water and length of the growing season associated with the thinning ice cover. In addition, climate models predict that the Arctic will experience greater and more rapid warming than other areas of the planet over the next century, suggesting that these changes may become even more prevalent in the future. The thinning sea ice has already had a dramatic impact on regional biogeochemistry: in 2011, we observed one of the most massive phytoplankton blooms ever recorded under the sea ice in the Chukchi Sea, an area traditionally thought of as too dark and too cold for massive blooms to occur. In the Chukchi, melt-ponds on the ice surface have proliferated to an extent that, in combination with the thinning ice cover, light penetration through the ice to surface waters is now sufficient for net photosynthesis to occur. The bloom we witnessed in 2011 extended for over 100 km into the> 1 m thick ice pack, and was characterized by extraordinarily high diatom biomass and rates of production. These changes represent a marked shift in our conception of Arctic marine ecosystems and have potential global-scale implications due to feedbacks relating to sea ice albedo, global atmospheric and ocean circulation patterns, and natural greenhouse gas exchanges between the atmosphere and ocean. Chapter 1 presents an overall introduction to the Arctic and discusses the causes and consequences of this changing seasonal cycle of productivity. Chapter 2 presents results from field work performed in the Beaufort Sea in the summer of 2008 exploring the spatial and temporal variability of phytoplankton photosynthesis in the ice-associated region of the flaw-lead polynya (area of perennially open water that rings the Arctic Ocean between land-fast ice and the central Arctic ice pack; it can be used somewhat as an analog for future open-water and ice-edged based productivity). Continuing with this theme of exploring primary productivity and biogeochemical cycles in the changing Arctic, Chapter 3 details the results from photophysiological experiments performed during the summer of 2010-2011 that highlight the unique features allowing Arctic phytoplankton to reach high levels of biomass in the extreme environment under the ice. In Chapter 4, I present data from recent 1-D modeling efforts that utilize the light and nutrient-controlled responses of phytoplankton growing under the ice to explore the consequences and implications of this shifting bloom cycle on regional biogeochemical processes.

Download or read book Reconciling particulate organic carbon flux and sediment community oxygen consumption in the deep North Pacific written by K.L. Smith and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: