BLOG HAS MOVED

This blog is now located at:

http://politicalecology.xyvy.info

Please update your browser settings.

Colonisation of fish and crabs of wave energy foundations and the effects of manufactured holes – A field experiment

Our field experiment examined the function of wave energy foundations as artificial reefs. In addition, potentials for enhancing the abundance of associated fish and crustaceans through manufactured holes of the foundations were also investigated. Assemblages of mobile organisms were examined by visual censuses in July and August 2007, 3 months after deployment of the foundations. Results generally show low densities of mobile organisms, but a significantly higher abundance of fish and crabs on the foundations compared to surrounding soft bottoms. Further, while fish numbers were not influenced by increased habitat complexity (holes), it had a significantly positive effect on quantities of edible crab (Cancer pagurus), on average leading to an almost five-fold increase in densities of this species. Densities of spiny starfish (Marthasterias glacialis) were negatively affected by the presence of holes, potentially due to increased predator abundance (e.g. C. pagurus). These results suggest a species-specific response to enhanced habitat complexity.

doi:10.1016/j.marenvres.2009.06.003   

Could There Be Another Origin For Fossil Fuels?

Hydrocarbons are generally thought to have a biological origin via the decomposition of ancient life over millions of years, hence the name ‘fossil fuels’. However, there is another theory that suggests hydrocarbons may also be created from non-biological (abiogenic) sources. Previous experiments have shown that abiogenic methane could exist in the Earth’s upper-mantle and theoretical models have predicted that this could then be converted to heavier hydrocarbons.Now, a team led by Alexander Goncharov at the Carnegie Institute of Washington in the US, say they have provided solid experimental data that support these predictions. ‘What we found, for the first time, is the transformation of methane to heavy hydrocarbons like propane or butane, under upper mantle conditions,’ says Goncharov.

From methane to liquid gold

Corn waste converted to nitrogen chemicals

Tijs Lammens, at Wageningen University, the Netherlands, and colleagues studied the conversion of glutamic acid to -aminobutyric acid (GABA) using a decarboxylase enzyme. Glutamic acid is a major component of the waste formed when grains, such as maize, are converted into bioethanol. Because glutamic acid contains nitrogen, it could be used to make nitrogen-containing industrial chemicals more cheaply than the energy intensive, fossil fuel- and ammonia-based routes usually used.

DOI: 10.1039/b913741f

Application of nanosilver surface modification to RO membrane and spacer for mitigating biofouling in seawater desalination

In the silver-coated spacer test, there was almost no multiplication of cells detected on the membrane during the whole testing period. Besides, the cells adhering to the membrane seemed to lose their activity quickly. According to the RO performance and microbial growth morphology, the nanosilver coating technology is valuable for use in biofouling control in seawater desalination.

doi:10.1016/j.watres.2009.06.002

Life cycle assessment study of a 4.2 kWp stand-alone photovoltaic system

The energetic and environmental life cycle assessment of a 4.2 kWp stand-alone photovoltaic system (SAPV) at the University of Murcia (south-east of Spain) is presented. PV modules and batteries are the energetically and environmentally most expensive elements. The energy pay-back time was found to be 9.08 years and the specific CO2 emissions was calculated as 131 g/kWh. The SAPV system has been environmentally compared with other supply options (diesel generator and Spanish grid) showing lower impacts in both cases. The results show the CO2-emission reduction potential of SAPV systems in southern European countries and point out the critical environmental issues in these systems.

doi:10.1016/j.solener.2009.03.012

Reproducing ten years of road ageing — Accelerated carbonation and leaching of EAF steel slag

Reuse of industrial aggregates is still hindered by concern for their long-term properties. This paper proposes a laboratory method for accelerated ageing of steel slag, to predict environmental and technical properties, starting from fresh slag. Ageing processes in a 10-year old asphalt road with steel slag of electric arc furnace (EAF) type in the subbase were identified by scanning electron microscopy (SEM) and leaching tests. Samples from the road centre and the pavement edge were compared with each other and with samples of fresh slag. It was found that slag from the pavement edge showed traces of carbonation and leaching processes, whereas the road centre material was nearly identical to fresh slag, in spite of an accessible particle structure.

doi:10.1016/j.scitotenv.2009.05.039

Follow

Get every new post delivered to your Inbox.