Tom Frost

Methane in the southern North Sea: Low‐salinity inputs, estuarine removal, and atmospheric flux

Dissolved CH4was measured in coastal waters of the southern North Sea, in two adjacent U.K. estuaries with well-defined turbidity maxima (Humber and Tyne) and in their associated river catchments, during a series of campaigns covering the period 1993–1999. In general, samples from all three environments were significantly to highly CH4 enriched relative to atmospheric air. Observed river water concentrations, ∼ 33–152 nmol L−1 (940–4305% saturation) for the Humber river catchment and ∼ 3–62 nmol L−1 (86–1754% saturation) in the river Tyne, were within but toward the low end of the range of CH4 concentrations in river waters world wide. In sea waters from the outer Wash estuary (U.K. coast) and adjacent to the Dutch coast, CH4 was highly but nonlinearly correlated with salinity, consistent with strong CH4 removal from river and/or estuarine CH4 sources influencing these locations. In transects along the Humber and Tyne estuaries, CH4 was highly negatively nonconservative, confirming the estuarine removal hypothesis. For both estuaries, highest CH4 concentrations, ∼190–670 nmol L−1 (6000–21,000% saturation) in the Humber and ∼650 nmol L−1(21,800% saturation) in the Tyne, were observed at very low salinity in the vicinity of the turbidity maximum. Importantly, these concentrations greatly exceeded measured river water values, implying for both situations the existence of a large in situ CH4 supply associated with high turbidity. Time series measurements at two locations in the upper Tyne subsequently confirmed the strong correspondence of dissolved CH4 and turbidity in the vicinity of the turbidity maximum. CH4removal estimated for the Humber, Tyne, Wash, and Rhine-Scheldt estuaries was ∼ 90% of the low-salinity CH4 input. On the basis of this and river discharge data, −7.I×108 mol CH4 may be removed annually in estuaries bordering the southern North Sea. Of this, ∼6.6×108mol may be lost by air-sea exchange. This represents an additional atmospheric CH4 flux from the North Sea unaccounted for in previous work, which may have, consequently, underestimated this source by ∼50%. Upward scaling of this estimate based on the mean of reported river water CH4 concentrations implies a previously unaccounted for ∼6.3–24×109 mol (i.e., ∼ 0.1–0.4 × 1012 g) CH4 yr−1 which may be lost globally to gas exchange in estuaries, increasing previous such estimates by ∼8–50%. However, as it is based on data that exclude the possibility of elevated CH4 levels at estuarine turbidity maxima, even this revision is likely to be conservative. Detailed studies of CH4 distributions in major world estuaries would now be required in order to successfully reevaluate the CH4 budget of the coastal marine atmosphere.

Bacterioneuston control of air-water methane exchange determined with a laboratory gas exchange tank

[1] The apparent transfer velocities (k w ) of CH 4 , N 2 O, and SF 6 were determined for gas invasion and evasion in a closed laboratory exchange tank. Tank water (pure Milli-RO® water or artificial seawater prepared in Milli-RO®) and/or tank air gas compositions were adjusted, with monitoring of subsequent gas transfer by gas chromatography. Derived k w was converted to apparent k 600 , the value for CO 2 in freshwater at 20°C. For CH 4 , analytical constraints precluded estimating apparent k 600 based on tank air measurements. In some experiments we added strains of live methanotrophs. In others we added chemically deactivated methanotrophs, non-CH 4 oxidizers (Vibrio), or bacterially associated surfactants, as controls. For all individual controls, apparent k 600 estimated from CH 4 , N 2 O, or SF 6 was indistinguishable. However, invasive estimates always exceeded evasive estimates, implying some control of gas invasion by bubbles. Estimates of apparent k 600 differed significantly between methanotroph strains, possibly reflecting species-specific surfactant release. For individual strains during gas invasion, apparent k 600 estimated from CH 4 , N 2 O, or SF 6 was indistinguishable, whereas during gas evasion, k 600 -CH 4 was significantly higher than either k 600 -N 2 O or k 600 -SF 6 , which were identical. Hence evasive k 600 -CH 4 /k 600 -SF 6 was always significantly above unity, whereas invasive k 600 -CH 4 /k 600 -SF 6 was not significantly different from unity. Similarly, k 600 -CR 4 /k 600 -SF 6 for the controls and k 600 -N 2 O/k 600 -SF 6 for all experiments did not differ significantly from unity. Our results are consistent with active metabolic control of CH 4 exchange by added methanotrophs in the tank microlayer, giving enhancements of ∼12 ± 10% for k 600 -CH 4 . Hence reactive trace gas fluxes determined by conventional tracer methods at sea may be in error, prompting a need for detailed study of the role of the sea surface microlayer in gas exchange.

The dispositif between Foucault and Agamben

This article interrogates the specter of resistance in the writings of Giorgio Agamben and Michel Foucault, arguing they open up divergent ways of theorizing resistance to power. This article’s focus is on both philosophers’ use and interpretation of the dispositif, or apparatus, which controls and orders subjects, and which is the target for forms of resistance. Whereas for Foucault resistance is a practice existing as a transcendent possibility for any individual, Agamben reads such transcendent forms of resistance as ultimately reinforcing the control of the dispositif, arguing that only a turn to ontology and immanent politics can resistance be meaningful.

The hyper-hermeneutic gesture of a subtle revolution

Abstract Drawing upon the thought of Giorgio Agamben, this essay focuses upon the potential of a single act to change a political order. Agamben’s writings retain the possibility for a paradigmatic gesture that opens a space for a politics not founded on a form of belonging grounded in a particular property, such as national identity. To illustrate this event this essay turns to Agamben’s construction of whatever-being, which is constructed hyper-hermeneutically. This term is chosen deliberately. Whatever-being retains a hermeneutic structure, but is constructed through singular paradigmatic examples. These examples are evidence for whatever-being’s existence as a pure singularity, unable to be reduced to a particular quality. Such examples are gestures that allow future modes of belonging to separate themselves from oppressive foundations and dominating constructions of political existence, through revealing the possibility of a new way of being that does not require a revolutionary “zero hour” to be brought about.

Justice in Transition: On Territory, Restitution and History

Colonialism has had a huge impact upon the legal systems of countries around the world. The historical impact of the British Empire can still be felt today in countries as diverse as Australia and South Africa. This effect is explored in both these countries, both in its historical form of racial discrimination, as well as the modern consequences of this colonial past. This chapter will reflect on the Aboriginal land rights litigation in Australia , as well as the failed South African Apartheid litigation. By using these as examples, it aims to determine how certain conceptions of the Rule of Law and formal equality can lead to profound and ingrained legal discrimination against indigenous peoples.

Thinking relationality in Agamben and Levinas

Giorgio Agambens development of a messianic politics-to-come seeks to counter the law which is in force without significance, a law which creates bare life. Embodying this messianic politics, and a call for the laws fulfilment, is the figure of whatever-being, a form-of-life. This article contends that there is an important conceptual problem in respect of Agambens construction of such a form-of-life, namely the issue of relationality. The problem of relationality in Agamben is explored here through the comparative lens of relationality in Levinass thought. It is contended that Agambens messianic subject, his form-of-life, has a negative relation to its other, in contrast to Levinass more positive, subject forming view of relationality.