Nitrous oxide emissions from the Arabian Sea | …

In Paleocene oceans, sharks filled the empty niches left by aquatic reptiles, but it took coral reefs ten million years to begin to recover, . As Africa and India moved northward, the shrank, and in the late Paleocene and early Eocene, one of the last Tethyan anoxic events laid down Middle East oil, and the last Paleocene climate event is called the (“PETM”). The PETM has been the focus of a great deal of recent research because of its parallels to today’s industrial era, when carbon dioxide and other greenhouse gases are massively vented to the atmosphere, causing a warming atmosphere and acidifying oceans. The seafloor communities suffered a mass extinction and the PETM’s causes are uncertain, but the when the global ocean warmed sufficiently is a prominent hypothesis. Scientists also look to the usual suspects of volcanism, changes in oceanic circulation, and a bolide impact.


a “hot spot” for nitrous oxide (N 2 O) emissions to the ..

Nitrous oxide emissions from the Arabian Sea: a synthesis.

This essay has presented Earth’s many changing faces during its journey. Earth had molten beginnings, was , and may have . Later, and and . Earth experienced swings from to conditions as atmospheric gases dramatically changed, continents moved, and vast and of complex life played out on land and sea. But the changes happened over timescales of millions and billions of years, not hundreds. No climate scientist will deny that carbon dioxide traps infrared radiation and warms Earth’s atmosphere. The vented enough carbon dioxide into the atmosphere to create 200 million years of Greenhouse Earth conditions, when reptiles ruled Earth. Volcanism waned and around 150-to-100 mya. By 35 mya, and the Antarctic ice sheet began forming. Every paleoclimate study I have seen places greenhouse gas (and primarily carbon dioxide) concentrations as the primary determinant of global surface temperatures, after the Sun's radiation, but the Sun's output is considered to have been exceptionally stable and has risen slowly over the eons. , usually by accentuating the carbon dioxide with a positive feedback effect that may have reached runaway conditions at times.

key factors on emissions of nitrous oxide in ..

In recent years, Neogene temperatures have been the focus of intensive research. What appears to be the proximate cause of elevated temperatures was a dramatic change in global ocean currents. The final closing of the , the isolation of Antarctica, the creation of , and the opening and closing of land bridges, such as in the Bering Sea and ultimately the land bridge between North and South America, created dramatic changes in ocean currents and global climate. One result was fluctuating . Its production declined beginning about 24 mya, and its weakness lasted until about 14 mya. Consequently, Earth’s oceans were not stratified as they are today, and warm water extended far lower into the oceans than it does today. Also, it reduced the temperature gradient between the equator and poles, which drives global currents: the greater the differential, the more vigorous the currents. It was still an Icehouse Earth, but the “mid-Miocene climatic optimum” was relatively warm. The past three million years are the coldest that Earth has seen since the that ended 260 mya, but this . While the steadily declining carbon dioxide levels of the past 150-100 million years is the ultimate cause of this Icehouse Earth phase, relatively short-term and regional fluctuations have had their proximate causes rooted in other geophysical, geochemical, and celestial dynamics.

Nitrous oxide emissions from
Our estimate of nitrous oxide emissions from the Peruvian coast surpasses values from similar, ..

et al: Nitrous oxide emissions from the Arabian Sea: ..

Environmental context. Nitrous oxide and methane are atmospheric trace gases and, because they are strong greenhouse gases, they contribute significantly to the ongoing global warming of the Earth’s atmosphere. Despite the well established fact that the world’s oceans release nitrous oxide and methane to the atmosphere, the oceanic emission estimates of both gases are only poorly quantified. The MEMENTO (MarinE MethanE and NiTrous Oxide) database initiative is proposed as an effective way by which existing nitrous oxide and methane measurements can be used to reduce the uncertainty of the oceanic emissions estimates by establishing a global database.

21/09/2012 · Variabilities in the fluxes and annual emissions of nitrous oxide ..

Distribution and air–sea exchange of nitrous oxide in …

Some scientists have warned that by the year 2200, at the current rate of greenhouse gas emissionsfrom human activities, the atmospheric levels of carbon dioxide, methane, and nitrous oxidewill be at the same levels associated with mass-extinction events in the Earth'spast.[8] The Earth's long-term future
The future of the Earth is linked to the fate of the Sun.

Distribution and air–sea exchange of nitrous oxide in the coastal Bay of ..

oceanic nitrous oxide emissions ..

We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N2O) to estimate the concentration of biologically produced N2O and N2O production rates in the ocean on a global scale. Our approach to estimate the N2O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N2O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N2O are not taken into account in our study. The largest amount of subsurface N2O is produced in the upper 500 m of the water column. The estimated global annual subsurface N2O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr−1. This is in agreement with estimates of the global N2O emissions to the atmosphere and indicates that a N2O source in the mixed layer is unlikely. The potential future development of the oceanic N2O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed.