The uptake of silica during the spring bloom in the North East Atlantic Ocean

A full understanding of the biogeochemical cycling of silica in the North Atlantic is hampered by a lack of estimates of silica uptake by phytoplankton. We applied the ${}^{32}\text{Si}$ radiotracer incubation technique to determine silica uptake rates at 10 sites during the UK-(Natural Environment Research Council) Faroes-Iceland-Scotland hydrographic and environmental survey (FISHES) cruise in the Northeast Atlantic, May 2001. Column silica uptake rates ranged between 6 and 166 mmol Si $\text{m}^{-2}\ \text{d}^{-1}$; this data set was integrated with concurrent hydrographic, chemical, and primary productivity data to explain these changes in silica uptake in terms of the progress of the spring bloom. In order to interpret data covering a relatively large spatial and temporal scale, we used mean photic zone silica concentration as a proxy time-series measure of diatom bloom progression. Both absolute and specific silica uptake rates were highest at dissolved silica concentrations >2 mmol $\text{L}^{-1}$. Si and C uptake were vertically decoupled at those stations where surface silica was strongly depleted. Absolute primary productivity was not strongly correlated with dissolved silica concentrations, owing to either exhaustion of silica at diatom-dominated stations or to dominance of the community by other phytoplankton. Silica uptake as a function of increased substrate concentration was linear up to 25 $\mu \text{mol}\ \text{L}^{-1}$; we consider some possible reasons for the nonhyperbolic response.

'Saig in Machai Fothúaid': On the Application and Extent of ‘the Macha’ in North-west Armagh

The seventh-century Patrician documents in the Book of Armagh, and other early sources such as Bethu Phátraic, contain references to the toponym Macha, which has been identified by the Dictionary of the Irish Language with either the ecclesiastical centre of Ard Macha or the ‘royal seat’ of Emain Macha. This article examines the evidence for the name in the sources and illustrates that Macha applies primarily to the plain in which both Ard Macha and Emain Macha are located. It is to be identified with Mag Macha ‘the plain of Macha’, familiar to us from the Dindshenchus, and further evidence of the organic potential of a given toponym is witnessed in later sources where the plain is referred to as Mag/Machaire na hE(a)mna ‘the plain of Emain’ and Machaire Aird/Arda Macha ‘the plain of Armagh’. The extent of Macha is difficult to establish with certainty, but it seems very likely that it stretched north to the River Blackwater as well as south towards Slíab Fúait.

Super suburbia: developing resilience by closing resource cycles in North Belfast

Sustainability can be described as having three interlinked strands, known as the ‘trias energetica’, without which resilience is difficult to achieve. These strands are environmental, social and economic: and if taken as indicators, the suburbs of North Belfast are very poorly performing indeed. Places such as Ligoneal and Glen Cairn have poor housing stock energetically, and also little economic activity. This paper describes propositional work completed by Queens University and Belfast City Council as part of the UK’s Technology Strategy Board’s Future Cities Programme, which aimed to develop new synergies in these neighbourhoods by the insertion of closed cycle economies.

By utilising a research by design methodology, the paper develops a process-based and phased design to develop a new emergent form to these neighbourhoods, one in which new productive systems are embedded into the city, at a small-scales. These include a peak-load hydro-electric project in Ligoneal; a productive landscape in Glen Cairn and a city-wide energy refurbishment utilising neighbourhood waste streams.

These designs allow for a roadmap for development to be created that could change the modus operandi of an area over a relatively short period of time, and show that even modest investments of productive technologies at a local scale could fundamentally change the form and the economic and environmental operation of the city in the future, and create a new resilient city, one that can be less externally dependent and more socially just.