Dorothee Bakker is a research fellow at the School of Environmental Sciences at the University of East Anglia in Norwich, UK. Baerbel Langmannis is a senior scientist at the Institute of Geophysics of the University of Hamburg, Germany.
Introduction
The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Many of the gases described, such as sulfur gases and non-methane hydrocarbons, are important for marine boundary layer particle formation and cloud coverage (Chapter 4).
Sulphur and Related Gases
Reaction chamber experiments indicate that net SO2 yields are in the range of 0.7-0.8 at room temperature (Barnes et al.2006 and references therein). The laboratory study of NOx oxidation by Patroescu et al. 1999) showed an increase in SO2 yield at lower NOx levels.
Halocarbon Gases
Thus, while Ooki et al. 2010) reported increased CH3Cl concentrations associated with elevated chlorophyll-a in the NW. Cyanobacteria have been shown to be a source of bromocarbon in the Baltic Sea (Karlsson et al. 2008). 1.3.3): monohalogenated organic compounds such as methyl iodide (CH3I), ethyl iodide (C2H5I) and propyl iodide (1- and 2-C3H7I); reactive polyhalogenated compounds such as chloroiodomethane (CH2ICl), bromoiodomethane (CH2IBr) and diiodomethane (CH2I2); and I2 (Saiz-Lopez et al. 2012).
Non-Methane Hydrocarbons (NMHCs)(NMHCs)
The results of Mao et al. 2006) agree with the findings of Marandino et al. In addition, it is likely that there is a bacterial source of alkyl nitrates from nitrification/denitrification processes (Hughes et al. 2010). They have been used extensively as potentially specific tracers of terrestrial biomass burning (Singh et al. 2010).
Ozone
Concentrations above the marine boundary layer drop significantly as expected from an oceanic sink (de Gouw et al. 2003). However, due to the large surface area of the ocean, the world's oceans are estimated to account for ~1/3 of the global surface area. ozone (Ganzeveld et al.2009) This gradient in marine ozone uptake was also observed in the oceanic ozone flux literature review and modeling work (Ganzeveld et al.2009).
Nitric Oxide
The most fundamental finding of this research is that chemical reactants in the surface ocean are the main drivers of ozone uptake. These applications have shown that the reaction of ozone with organic compounds results in the formation of soluble oxygenated organics such as aldehydes, ketones, and acids (von Gunten 2003). The increase in ozone loading observed in the MBL implies that the rate of ozone input to the ocean has increased since pre-industrial times.
Ammonia and Amines
Typically, NH3 concentrations in the marine atmosphere are on the order of 0.1–10 nmol m3 (mid- to high ppt concentrations), but they can be orders of magnitude higher in polluted land environments (Johnson et al.2008; Dentener et al. .2006). However, transient biologically driven peaks in NH3 concentration in the surface oceans can drive emission events in regions where the flux may be typical in the ocean (Johnson et al.2007). A recent review identified >150 amine species that have been measured in the atmosphere or are known to be produced (Ge et al.2011).
Hydrogen
There is increasing atmospheric concentration data for the low molecular weight alkylamines (e.g. Mu¨ller et al.2009). For ammonia, the literature is contradictory, with some experimental and modeling studies suggesting that ammonia significantly improves the formation of ternary new particles from water and sulfuric acid (Coffman and Hegg1995; Korhonen et al.1999); However, recent research suggests that ammonia may play an important role in particle formation and growth (Kirkby et al.2011; Benson et al.2011).
Carbon Monoxide
Whatever the production processes, the measured supersaturations lead to a net flux of H2 from the oceans to the atmosphere, the estimates of which range from 3 to 6 Tg per year1, with an uncertainty in each estimate of 50% or more (Schmidt1974; Conrad and Seiler 1986). ; Novelli et al., 1999; Rhee et al., 2005). Based on simultaneous measurements of CO in seawater and the atmosphere over the Pacific Ocean, Bates et al. conclude that further work combining field measurements (in less documented areas) with new approaches to infer global fluxes will help improve the estimates of the marine CO source.
Concluding Remarks
Coffman DJ, Hegg DA (1995) A preliminary study of the effect of ammonia on particle nucleation in the marine boundary layer. Harrison JJ, Allen NDC, Bernath PF (2011a) Infrared absorption cross sections for acetone (propanone) in the 3μm region. Kaltsoyannis N, Plane JMC (2008) Quantum chemical calculations on a selection of iodine-containing species (IO, OIO, INO3, (IO)2, I2O3, I2O4and I2O5) of interest in the atmosphere.
Introduction
Most often, the transfer is described by various functional dependencies on the wind speed, but more detailed descriptions require additional information. For global flux estimates using inventories or remote sensing products, the accuracy of the transfer formulation as well as the accuracy of the wind field is critical. The accuracy of the various methods and the importance of measurement uncertainty for global flux estimates are further discussed.
Processes
Therefore, Ja¨hne et al. 1987) have argued that the slope of the waves is representative of the near-surface turbulence produced by wave breaking on the microscope. The wave direction may differ from the wind direction (Pettersson et al. 2010), depending on the geometry of the entrainment. A recent study (Wurl et al. 2011) showed that many of the world's oceans (subtropical, temperate and polar) are significantly covered by surfactants.
Process Models
This led to the application of Harriott's (1962) surface penetration model to detailed heat and mass flux data from Asher et al. The total transfer resistanceR is the sum of the transfer resistanceRwin the water and rain the air phase. From the knowledge of the Schmidt numbers of two types Sc1 and Sc2 and the transfer rate of one (k1), the transfer rate of the other (k2) can be easily calculated.
Measurement Techniques
Infrared measurements of the sea surface have been used to detect breaking waves (Jessup et al.1997a) and microscale breaking waves (Jessup et al.1997b). This version of the EC method is called Disjunct Eddy Covariance (DEC) and has been verified experimentally with the EC method (e.g. Rinne et al. 2008). This correction can be applied in post-processing or directly on the measured time series (Sahle´e et al. 2008).
Parameterization of Gas Exchange
NOAA-COARE
In the COARE gas transfer algorithm (COAREG), the flux of a trace gas on the atmospheric side of the interface is estimated as. For example, when considering fluxes of CO2 on a global scale, there is a limit on the transfer rate given the bomb 14C inventory of the ocean (eg Sweeney et al. 2007). Selection of an appropriate baud rate should be based on the requirements of the particular study.
Sea Ice
Therefore, the mode and potential magnitude of air-ice gas flows are controlled by the gas dynamics in the sea ice, rather than by the gas content of the underlying water. Under certain sea ice permeability conditions, assuming that CaCO3 precipitates in the early growth phase of the sea ice (Assur 1958; Marion et al. 2009), CO2 produced by CaCO3 precipitation is discharged to the underlying water along with brine. 2011) has recently produced a first preliminary estimate of the global significance of sea ice-related processes for atmospheric CO2 uptake.
Applications of Air-Sea Gas TransferTransfer
This is probably a consequence of the influential paper by Sarmiento et al. 1992) where the authors showed little sensitivity of anthropogenic CO2 uptake to different gas transfer rate formulations. For DMS and N2O, virtually all models have used Wanninkhof's (1992) gas transfer formulation to represent the air-sea flux of these gases (Le Clainche et al. 2010; Wanninkhof (1998) to scale the bubble-mediated flux by the cubic power of wind speed (Hamme and Severinghaus 2007; Ito et al. 2011), but other powers have also been used (Spitzer and Jenkins 1989).
Summary
Bock EJ, Hara T, Frew NM, McGillis WR (1999) Relationship between air-sea gas transfer and short wind waves. In: Garbe C, Handler RA, Ja¨hne B (eds) Transport at the air-sea interface – measurements, models and parameterizations. In: Garbe CS, Handler RA, Ja¨hne B (eds) Transport at the air-sea interface – measurements, models and parameterizations.
Introduction
Given its current tropospheric increase and continued decline in chlorofluorocarbon (CFC) emissions, N2O may soon replace CFCs as the fourth most important greenhouse gas after water vapor (H2O), CO2 and CH4 (Forster et al. 2007). Indeed, N2O is expected to become the dominant O3-reducing component during the twenty-first century (Ravishankara et al.2009). Variations in stratospheric N2O between 200 and 280 ppb over the past 650,000 years (Spahni et al. 2005) can be attributed to simultaneous natural changes in both terrestrial and oceanic sources (Sowers et al.
Surface Ocean Distribution and Air-Sea Exchange of CO 2and Air-Sea Exchange of CO2
Interestingly, however, Watson et al. 2009) derived similar air-sea CO2 fluxes for the North Atlantic Ocean (10–65N) using multiple linear regression. Outer estuaries (estuarine plumes) have a limited salinity range and salinities are typically below 34 (Frankignoulle et al. 1998). The assessment by Laruelle et al. 2010) is based on an estuary typology with four types (small deltas and small estuaries, tidal and inlet systems, lagoons, fjords and fja¨rds (sea bays that have been exposed to glacial accretion, in a rocky area of low topography). )).
Marine Distribution and Air-Sea Exchange of N 2 OExchange of N2O
During a period of eutrophication reversal from the mid-1980s onwards, in which river-borne nitrogen inputs continued to increase and phosphorus inputs decreased, primary production in the southern North Sea declined due to phosphorus limitation and the system was diverted back to the source of tropospheric CO2. However, the enzymes involved in the nitrifier-denitrification pathway differ from those involved in classical denitrification (section 3.3.2.1). This means that significant in situ production of N2O in the upper mixed layer is unlikely, as this layer tends to be well oxygenated.
Under the oxygen conditions present in more than 90% of the ocean, N2O is formed as a metabolic byproduct during nitrification, the stepwise oxidation of NH4+. Alternatively, N2O can be formed during the reduction of NO2 via nitric oxide (NO) to N2O, the so-called nitrification-denitrification pathway (Cantera . and Stein2007). This view has since been revised in light of recent work showing that AOA are the key organisms for oceanic nitrification (Wuchter et al and that AOA are able to produce large amounts of N2O (Santoro et al. 2011; Lo¨scher et al. et al. 2012).
Marine Distribution and Air-Sea Exchange of CH 4Exchange of CH4
Methanogenesis rates were estimated to be near maximal for ambient temperature (Nirmal Rajkumar et al.2008). 3.16 (a) Distribution of known and derived accumulations of methane hydrate; (b) estimated thickness of the gas hydrate stability zone (GHSZ) in seafloor sediments (adopted from Krey et al. The total CH4 emission from open ocean regions, where O2 depletion occurs in the water column, is quite small (0.3 Tg C year1) (Bates et al.1996b).
Impact of Global Change
The estimate of CH4 emissions from estuaries and manbo sites (Table 3.7) is compounded by uncertainties about ebullition rates. Importantly, although ebullition may account for more than 90 % of CH4 emissions at some locations (Ostrovsky2003; Barnes et al.2006; Nirmal Rajkumar et al.2008), it is excluded from routine air-sea emission estimates based on applied gas exchange ratios on dissolved gas gradients (Upstill-Goddard2006). Although some progress has been made to estimate the global area of estuarine water bodies (Du¨rr et al.2011), no robust estimate is currently available for the global intertidal area.
