The Role of Local Populations within a Landscape Context: Defining and Classifying Sources and Sinks

2006 ◽  
Vol 167 (6) ◽  
pp. 925 ◽  
Author(s):  
Runge ◽  
Runge ◽  
Nichols
Keyword(s):  
Landscape Context ◽  
Sources And Sinks ◽  
Local Populations

The Role of Local Populations within a Landscape Context: Defining and Classifying Sources and Sinks

2006 ◽  
Vol 167 (6) ◽  
pp. 925-938 ◽  
Author(s):  
Jonathan P. Runge ◽  
Michael C. Runge ◽  
James D. Nichols
Keyword(s):  
Landscape Context ◽  
Sources And Sinks ◽  
Local Populations

Quantifying sources and sinks of trace gases using space-borne measurements: current and future science

2008 ◽  
Vol 366 (1885) ◽  
pp. 4509-4528 ◽  
Author(s):  
Paul I Palmer
Keyword(s):  
Trace Gases ◽  
Lower Troposphere ◽  
Biological Interactions ◽  
Satellite Measurements ◽  
Sources And Sinks ◽  
The Past ◽  
Fundamental Understanding ◽  
Earth’S Climate ◽  
New Generation

We have been observing the Earth's upper atmosphere from space for several decades, but only over the past decade has the necessary technology begun to match our desire to observe surface air pollutants and climate-relevant trace gases in the lower troposphere, where we live and breathe. A new generation of Earth-observing satellites, capable of probing the lower troposphere, are already orbiting hundreds of kilometres above the Earth's surface with several more ready for launch or in the planning stages. Consequently, this is one of the most exciting times for the Earth system scientists who study the countless current-day physical, chemical and biological interactions between the Earth's land, ocean and atmosphere. First, I briefly review the theory behind measuring the atmosphere from space, and how these data can be used to infer surface sources and sinks of trace gases. I then present some of the science highlights associated with these data and how they can be used to improve fundamental understanding of the Earth's climate system. I conclude the paper by discussing the future role of satellite measurements of tropospheric trace gases in mitigating surface air pollution and carbon trading.

scholarly journals The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle

2017 ◽  
Author(s):  
Didier Paillard
Keyword(s):  
Carbon Cycle ◽  
Ice Core ◽  
Climate Science ◽  
Atmospheric Concentration ◽  
Sources And Sinks ◽  
Climatic Evolution ◽  
Astronomical Forcing ◽  
The Antarctic ◽  
Simple Dynamical Model

Abstract. Since the discovery of ice ages in the XIXth century, a central question of climate science has been to understand the respective role of the astronomical forcing and of greenhouse gases, in particular changes in the atmospheric concentration of carbon dioxide. Glacial-interglacial cycles have been shown to be paced by the astronomy with a dominant periodicity of 100 ka over the last million years, and a periodicity of 41 ka between roughly 1 and 3 million years before present (MyrBP). But the role and dynamics of the carbon cycle over the last 4 million years remain poorly understood. In particular, the transition into the Pleistocene about 2.8 MyrBP or the transition towards larger glaciations about 0.8 MyrBP (sometimes refered as the mid-pleistocene transition, or MPT) are not easily explained as direct consequences of the astronomical forcing. Some recent atmospheric CO2 reconstructions suggest slightly higher pCO2 levels before 1 MyrBP and a slow decrease over the last few million years (Bartoli et al., 2011; Seki et al., 2010). But the dynamics and the climatic role of the carbon cycle during the Plio-Pleistocene period remain unclear. Interestingly, the d13C marine records provide some critical information on the evolution of sources and sinks of carbon. In particular, a clear 400-kyr oscillation has been found at many different time periods and appears to be a robust feature of the carbon cycle throughout at least the last 100 Myr (eg. Paillard and Donnadieu, 2014). This oscillation is also visible over the last 4 Myr but its relationship with the eccentricity appears less obvious, with the occurrence of longer cycles at the end of the record, and a periodicity which therefore appears shifted towards 500-kyr (cf. Wang et al., 2004). In the following we present a simple dynamical model that provides an explanation for these carbon cycle variations, and how they relate to the climatic evolution over the last 4 Myr. It also gives an explanation for the lowest pCO2 values observed in the Antarctic ice core around 600–700 kyrBP. More generally, the model predicts a two-step decrease in pCO2 levels associated with the 2.4 Myr modulation of the eccentricity forcing. These two steps occur respectively at the Plio-Pleistocene transition and at the MPT, which strongly suggests that these transitions are astronomicaly forced through the dynamics of the carbon cycle.

scholarly journals Field theory approach in kinetic reaction: Role of random sources and sinks

2011 ◽  
Vol 169 (1) ◽  
pp. 1489-1498 ◽  
Author(s):  
M. Hnatich ◽  
J. Honkonen ◽  
T. Lučivjanský
Keyword(s):  
Field Theory ◽  
Theory Approach ◽  
Kinetic Reaction ◽  
Sources And Sinks

Key Role of Equilibrium HONO Concentration over the Soil 

2021 ◽  
Author(s):  
Fengxia Bao ◽  
Hang Su ◽  
Uwe Kuhn ◽  
Yafang Cheng
Keyword(s):  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Nitrous Acid ◽  
Measurement Method ◽  
Oxidative Capacity ◽  
Sources And Sinks ◽  
Dynamic Chamber ◽  
Open Question ◽  
Actinic Radiation

<p>Nitrous acid (HONO) is an important component of the nitrogen cycle. HONO can also be rapidly photolyzed by actinic radiation to form hydroxyl radicals (OH) and exerts a primary influence on the oxidative capacity of the atmosphere. The sources and sinks of HONO, however, are not fully understood. Soil nitrite, produced via nitrification or denitrification, is an important source for the atmospheric HONO production. [HONO]*, the equilibrium gas phase HONO concentration over the soil, has been suggested as key to understanding the environmental effects of soil fluxes of HONO (Su et al., 2011). But if and how [HONO]* may exist and vary remains an open question. In this project, a measurement method using a dynamic chamber has been developed to derive [HONO]* and the atmospheric soil fluxes of HONO can accordingly be quantified. We demonstrate the existence of [HONO]* and determine its variation in the course of soil drying processes. We show that when [HONO]* is higher than the atmospheric HONO concentration, HONO will be released from soil; otherwise, HONO will be deposited on soil. This work advances the understanding of soil HONO emissions, and the evaluation of its impact on the atmospheric oxidizing capacity and the nitrogen cycling.</p>

scholarly journals Possible molecular genetic mechanisms of resistance in populations of the Colorado potato beetle

2020 ◽  
Vol 18 ◽  
pp. 00004
Author(s):  
Galina Benkovskaya
Keyword(s):  
Insecticide Resistance ◽  
Colorado Potato Beetle ◽  
Molecular Genetic ◽  
Membrane Channels ◽  
Mechanisms Of Resistance ◽  
Local Populations ◽  
Genetic Base ◽  
Potato Beetle ◽  
Genetic Mechanisms

Expansion of the Colorado potato beetle (CPB) in the Eurasia is continuing. At the same time, there is an increase in the level of insecticide resistance in populations of CPB in Russia. Regular detection of individuals resistant to diagnostic doses of insecticides during the last 10 years shows an increase of their prevalence in local populations in Bashkortostan. Genetic base of insecticide resistance in the Colorado potato beetle populations contains both mutations in the genes of target receptors or membrane channels, as well as changes in expression of these and many other genes. Role of the diapause proteins capable to bind xenobiotics and withdraw them from metabolism is discussed.

scholarly journals The Plio-Pleistocene climatic evolution as a consequence of orbital forcing on the carbon cycle

2017 ◽  
Vol 13 (9) ◽  
pp. 1259-1267 ◽  
Author(s):  
Didier Paillard
Keyword(s):  
Carbon Cycle ◽  
Ice Core ◽  
Climate Science ◽  
Atmospheric Concentration ◽  
Sources And Sinks ◽  
Climatic Evolution ◽  
Astronomical Forcing ◽  
The 19Th Century ◽  
The Antarctic

Abstract. Since the discovery of ice ages in the 19th century, a central question of climate science has been to understand the respective role of the astronomical forcing and of greenhouse gases, in particular changes in the atmospheric concentration of carbon dioxide. Glacial–interglacial cycles have been shown to be paced by the astronomy with a dominant periodicity of 100 ka over the last million years, and a periodicity of 41 ka between roughly 1 and 3 million years before present (Myr BP). But the role and dynamics of the carbon cycle over the last 4 million years remain poorly understood. In particular, the transition into the Pleistocene about 2.8 Myr BP or the transition towards larger glaciations about 0.8 Myr BP (sometimes referred to as the mid-Pleistocene transition, or MPT) are not easily explained as direct consequences of the astronomical forcing. Some recent atmospheric CO2 reconstructions suggest slightly higher pCO2 levels before 1 Myr BP and a slow decrease over the last few million years (Bartoli et al., 2011; Seki et al., 2010). But the dynamics and the climatic role of the carbon cycle during the Plio-Pleistocene period remain unclear. Interestingly, the δ13C marine records provide some critical information on the evolution of sources and sinks of carbon. In particular, a clear 400 kyr oscillation has been found at many different time periods and appears to be a robust feature of the carbon cycle throughout at least the last 100 Myr (e.g. Paillard and Donnadieu, 2014). This oscillation is also visible over the last 4 Myr but its relationship with the eccentricity appears less obvious, with the occurrence of longer cycles at the end of the record, and a periodicity which therefore appears shifted towards 500 kyr (see Wang et al., 2004). In the following we present a simple dynamical model that provides an explanation for these carbon cycle variations, and how they relate to the climatic evolution over the last 4 Myr. It also gives an explanation for the lowest pCO2 values observed in the Antarctic ice core around 600–700 kyr BP. More generally, the model predicts a two-step decrease in pCO2 levels associated with the 2.4 Myr modulation of the eccentricity forcing. These two steps occur respectively at the Plio-Pleistocene transition and at the MPT, which strongly suggests that these transitions are astronomically forced through the dynamics of the carbon cycle.

Growth, nitrogen fixation, respiration, and a nitrogen budget for cultures of a cosmopolitan diazotrophic endosymbiont (Teredinibacter turnerae) of shipworms

2013 ◽  
Vol 94 (1) ◽  
pp. 177-185 ◽  
Author(s):  
Rachel E.A. Horak ◽  
Joseph P. Montoya
Keyword(s):  
Gill Tissue ◽  
N Budget ◽  
Respiration Activity ◽  
Total N ◽  
Sources And Sinks ◽  
N Incorporation ◽  
Microaerobic Conditions ◽  
Rates Of Growth ◽  
Wood Boring

Wood-boring bivalves (Bivalvia, family Teredinidae), also known as shipworms, host dinitrogen-fixing and cellulolytic symbiotic bacteria in gill bacteriocytes, which may be a necessary adaptation to a wooden diet. Although oxygen (O2) inhibits nitrogenase in other species, symbionts are able to fix nitrogen (N) within the gill tissue and provide newly fixed N to the host shipworm. The recent direct evidence of new N incorporation into the host tissue indicates that there are potentially complex nutrient cycles in this symbiosis and uninvestigated controls upon these cycles.To elucidate the mechanisms of this unique N2-fixing symbiosis and determine whether symbionts can excrete newly fixed N, we measured rates of growth, N2-fixation, respiration, and inorganic N content for the cultivated symbiontTeredinibacter turnerae(γ-proteobacteria, strain T7901) under a range of headspace O2conditions. In all conditions, headspace O2did not affect maximum specific N2-fixation and respiration activity, but did influence the rate and timing of growth. These results are consistent with the development of microaerobic conditions through an oxygen gradient in the culture medium, which facilitates N2-fixation and growth. The medium accumulated a small amount of NH4+, which represented 0.5–2.5% of the total N fixed by the culture. We constructed a simple N budget forT. turneraeto assess the role of the major known N sources and sinks. The N budget was not closed, indicating that new N is allocated to currently unidentified sinks, which may include excreted dissolved organic nitrogen.

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