Tracing the Dynamics of Dissolved Organic Matter in Marine Systems Exposed to Natural and Experimental Perturbations PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Tracing the Dynamics of Dissolved Organic Matter in Marine Systems Exposed to Natural and Experimental Perturbations PDF full book. Access full book title Tracing the Dynamics of Dissolved Organic Matter in Marine Systems Exposed to Natural and Experimental Perturbations by Francisco Luis Aparicio Bernat. Download full books in PDF and EPUB format.
Author: Francisco Luis Aparicio Bernat
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author: Francisco Luis Aparicio Bernat
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author: Francisco Luis Aparicio Bernat
Publisher:
ISBN:
Category :
Languages : en
Pages : 184
Get Book Here
Book Description
In the coming decades, global warming will affect the biogeochemical cycles evolution, particularly the carbon cycle. In this context, it is necessary to gain knowledge on the Earth natural mechanisms to relieve the atmosphere of the greenhouse gases excess. The "biological pump" is one of the main mechanisms employed by the oceans to "sequester" the CO2 accumulated in the atmosphere. Thereby, the organic carbon produced by the biological activity is transferred from surface to deep waters where part of this pool is accumulated in the seafloor. Another mechanism involving the accumulation of carbon in the ocean, called the "microbial carbon pump" (MCP), has been described recently. It is composed by an intricate set of microbial processes that enable the formation of highly recalcitrant dissolved material and therefore facilitate the accumulation of carbon in the deep waters. The oceans store about 660 Pg C in the form of dissolved organic matter (DOM), a quantity comparable to the atmospheric CO2. Understanding the processes that control the dynamics, recycling and exportation of the DOM is crucial to evaluate the oceans capability to gather the excess of atmospheric CO2. On its course down throughout the water column, microorganisms degraded the DOM produced at the surface layers. Concentrations decrease from ̃90 μmol C L-1 down to 40-50 μmol C L-1, values homogeneously distributed in the deep oceans throughout the planet. The fact that below 1000 m and deeper the DOM is degraded at lower speed is still unknown, and the processes that can affect this DOM degradation have been studied in this thesis. In this regard, we performed experiments with deep Atlantic Ocean microbial communities. These communities were exposed to DOM of different quality. The results revealed that the presence of humic-like allocthonous compounds favored the generation of new humic-like compounds in situ. Consequently, we proved that the composition of the DOM that reach the deep ocean conditions its ease-to-degrade nature. In this thesis we also evaluated the effect of global change (acidification and eutrophication) on the quality of the DOM. With this purpose in mind, we developed mesocosms experiments in tanks of 200 L in which we enclosed coastal planktonic communities from the NW Mediterranean Sea. The planktonic populations were exposed to different treatments of pH and eutrophication (addition of inorganic nutrients). The results of these experiments demonstrated that low pH levels favored the increase of the planktonic organisms' growth rates, while the input of nutrients promoted the transformation to complex DOM. Finally, a monthly monitoring sampling of several biogeochemical variables was carried out at the Estartit Oceanographic Station (EOS). One of the principal aims consisted in identify the DOM sources and its inter-annual variability. The results revealed the importance of the winds in transporting oceanic DOM inputs to the system, which contrasted with previous results observed in nearby sampling stations (e.g. Blanes Bay, Bay of Banyuls-sur-mer), where the major DOM contributions were terrestrial inputs.
Author: Francisco Luis Aparicio-Bernat
Publisher:
ISBN:
Category :
Languages : en
Pages : 173
Get Book Here
Book Description
Author: Dennis A. Hansell
Publisher: Academic Press
ISBN: 0124071538
Category : Science
Languages : en
Pages : 712
Get Book Here
Book Description
Marine dissolved organic matter (DOM) is a complex mixture of molecules found throughout the world's oceans. It plays a key role in the export, distribution, and sequestration of carbon in the oceanic water column, posited to be a source of atmospheric climate regulation. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, focuses on the chemical constituents of DOM and its biogeochemical, biological, and ecological significance in the global ocean, and provides a single, unique source for the references, information, and informed judgments of the community of marine biogeochemists. Presented by some of the world's leading scientists, this revised edition reports on the major advances in this area and includes new chapters covering the role of DOM in ancient ocean carbon cycles, the long term stability of marine DOM, the biophysical dynamics of DOM, fluvial DOM qualities and fate, and the Mediterranean Sea. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, is an extremely useful resource that helps people interested in the largest pool of active carbon on the planet (DOC) get a firm grounding on the general paradigms and many of the relevant references on this topic. Features up-to-date knowledge of DOM, including five new chapters The only published work to synthesize recent research on dissolved organic carbon in the Mediterranean Sea Includes chapters that address inputs from freshwater terrestrial DOM
Author: N. Handa
Publisher: Springer Science & Business Media
ISBN: 9401713197
Category : Science
Languages : en
Pages : 561
Get Book Here
Book Description
Over the past decade the scientific activities of the Joint Global Ocean Flux Study (JGOFS), which focuses on the role of the oceans in controlling climate change via the transport and storage of greenhouse gases and organic matter, have led to an increased interest in the study of the biogeochemistry of organic matter. There is also a growing interest in global climate fluctuations. This, and the need for a precise assessment of the dynamics of carbon and other bio-elements, has led to a demand for an improved understanding of biogeochemical processes and the chemical characteristics of both particulate and dissolved organic matter in the ocean. A large amount of proxy data has been published describing the changes of the oceanic environment, but qualitative and quantitative estimates of the vertical flux of (proxy) organic compounds have not been well documented. There is thus an urgent need to pursue this line of study and, to this end, this book starts with several papers dealing with the primary production of organic matter in the upper ocean. Thereafter, the book goes on to follow the flux and characterization of particulate organic matter, discussed in relation to the primary production in the euphotic zone and resuspension in the deep waters, including the vertical flux of proxy organic compounds. It goes on to explain the decomposition and transformation of organic matter in the ocean environment due to photochemical and biological agents, and the reactivity of bulk and specific organic compounds, including the air-sea interaction of biogenic gases. The 22 papers in the book reflect the interests of JGOFS and will thus serve as a valuable reference source for future biogeochemical investigations of both bio-elements and organic matter in seawater, clarifying the role of the ocean in global climate change.
Author: K. Salonen
Publisher: Springer Science & Business Media
ISBN: 9401124744
Category : Science
Languages : en
Pages : 292
Get Book Here
Book Description
Concentrations of dissolved organic matter (DOM) in lakes are often an order of magnitude greater than concentrations of particulate organic matter; nevertheless, the biogeochemical analysis of DOM is described in only a few textbooks on limnology (most thoroughly by Wetzel). The orgins of dissolved organic substances are largely photosynthetic; DOM is either autochthonously synthesized by littoral and pelagic flora through secretions and autolysis of cellular contents, or allochthonously generated in terrestrial systems of the drainage basin, composing largely of humic substances refractory to rapid microbial degradation. The role of DOM in lacustrine ecosystems, as energy source and system regulator, however, is still poorly known. The aim of this book is: (1) to present state-of-the-art reviews of the role of dissolved autochthonous and allochthonous organic matter in pelagial and littoral zones; and (2) to focus attention on poorly understood but critical topics and hence to provide direction for future research activity.
Author: Christopher L. Osburn
Publisher: Frontiers Media SA
ISBN: 2889450813
Category :
Languages : en
Pages : 244
Get Book Here
Book Description
A substantial increase in the number of studies using the optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) as a proxy for its chemical properties in estuaries and the coastal and open ocean has occurred during the last decade. We are making progress on finding the actual chemical compounds or phenomena responsible for DOM’s optical properties. Ultrahigh resolution mass spectrometry, in particular, has made important progress in making the key connections between optics and chemistry. But serious questions remain and the last major special issue on DOM optics and chemistry occurred nearly 10 years ago. Controversies remain from the non-specific optical properties of DOM that are not linked to discrete sources, and sometimes provide conflicting information. The use of optics, which is relatively easier to employ in synoptic and high resolution sampling to determine chemistry, is a critical connection to make and can lead to major advances in our understanding of organic matter cycling in all aquatic ecosystems. The contentions and controversies raised by our poor understanding of the linkages between optics and chemistry of DOM are bottlenecks that need to be addressed and overcome.
Author: Jessica Wong
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
In aquatic ecosystems, dissolved organic matter (DOM) is an important source of detrital energy on which microorganisms rely. However, its dynamics are not well understood in an ecological context. By isolating watershed sources, the work reported in this thesis has attempted to characterize the seasonal patterns of DOM in the hyporheic zone of a temperate stream and to find the likely sources that contribute to this pool of organic carbon. Hyporheic DOM characteristics described by UV spectroscopy indicated temporal rather than spatial dependence. Excitation-emission matrices (EEMs) showed that hyporheic DOM was mainly comprised of fulvic- and humic-like fluorescence with small amounts of protein-like fluorescence. Increases in dissolved organic carbon (DOC) concentrations from birch litter isolates were greater than those from cedar litter in early autumn, but less in late autumn. Although streambed biofilm was not significant in increasing DOC concentrations, it was also a source of protein-like fluorescence.
Author: National Research Council
Publisher: National Academies Press
ISBN: 030916155X
Category : Science
Languages : en
Pages : 200
Get Book Here
Book Description
The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.
Author: Stuart Findlay
Publisher: Academic Press
ISBN: 0122563719
Category : Nature
Languages : en
Pages : 534
Get Book Here
Book Description
Overviews of the source, supply and variability of DOM, surveys of the processes that mediate inputs to microbial food webs, and syntheses consolidating research findings provide a comprehensive review of what is known of DOM in freshwater. This book will be important to anyone interested in understanding the fundamental factors associated with DOM that control aquatic ecosystems."--BOOK JACKET.
