Inhibition of phytoplankton photosynthesis by the WSF of used lubricating oil

The photosynthetic rates of five phytoplankton species were inhibited following treatment with the water-soluble fractions (WSF) of used lubricating oil. Exhaust oil from an outboard motor inhibited photosynthesis in three out of the five species tested which indicates a species specific response in the case of this form of oil pollution. Water-soluble fractions from Qatar crude had no inhibitory effect on any of the species tested but had a stimulatory effect on the photosynthetic rate of one species. Both oxygen evolution and carbon assimilation were inhibited by the water-soluble fraction of used lubricating oil. In four out of five species, used lubricating oil WSF caused a net oxygen consumption during the light phase rather than a net oxygen release. These data indicate that used lubricating oil water-soluble fractions are especially toxic to phytoplankton.     

Interactive Videos Enhance Learning about Socio-Ecological Systems

Two forms of interactive video were assessed in an online course focused on conservation. The hypothesis was that interactive video enhances student perceptions about learning and improves mental models of social-ecological systems. Results showed that students reported greater learning and attitudes toward the subject following interactive video. Moreover, metrics of network complexity applied to students' concept maps of socio-ecological systems increased longitudinally through the course highlighting greater awareness of socio-ecological linkages. We conclude that interactive video can increase awareness of interdisciplinary connections in socio-ecological systems and should be more widely employed in general education geography courses.     

Education in cartography: what is the status of young people’s map-reading skills?

Due to recent technological progress, maps have become more popular than ever before. This is especially true for young people, who interact with these technologies on a daily basis. Therefore, it is essential that these potential map users possess sufficient knowledge and skills to process the content of cartographic products. A user study was conducted during which pupils (aged 11–18 years) and geography students (>18 years) had to solve a number of cartography questions using topographic maps. The data were analyzed statistically, taking into account a number of potentially influencing factors (user characteristics) on the participants’ results: age, gender, youth club membership, knowledge about the area, among others. The results show a rising trend in the pupils’ scores with increasing age, which can be explained by education in cartography at school. Geography students perform much better, but no influence of any other user characteristics was detected. For pupils, knowledge about the area and gender might be considered as influencing factors. However, the detected influence of gender depends on the scoring system.     

Integrative multiplicity through suburban realities: exploring diversity through public spaces in Scarborough

Questions of “integration” are normatively assumed to promote particular ideals of the multicultural city and lead to a “settlement” culture that bodes well with the hegemonic majority. This paper, however, questions the concept from an alternative perspective – that is, it aims to explore how “integration” is imagined and understood by displaced migrants through the contextual specificities of multiple and peripheral “public spaces” – defined in this paper as the everyday practices of integrative multiplicity. Exploring these questions in Scarborough, a post-war primarily ethno-racialized suburb of Toronto, the unique experiences of migrants, many who have faced histories of trauma and violence suggest that the settlement experience is not devoid of anxiety and pain. Memories of places and communities left behind, sometimes never to be returned to, harness a longing and deeper need for home-making often spilling into the public realm. Understanding public space and its inherent conceptual and political complexity as defined, used, and valued by recent migrants, allows integration to be understood through the dynamics of power relations. The findings reveal how recent migrants not only understand and use the city but also how they reflect upon and envision the city-building process, through their own individual subjectivities of inclusion/place-making and exclusion/displacement. Through such complex spaces of encounter, civic engagement and grounded experiences, the participants frame Scarborough in multiple and metaphorical forms: from a City of Refuge and Peace; City of Memory, Desire, and Imagination; City of Multifariousness; to a City of Civic Engagement and Fluid Resistance. This stands in stark contrast from how the city is framed in dominant discourse and the unsettling debates on how to reform it.     

Hydrogen peroxide production rates in clean and polluted coastal marine waters of the Mediterranean, Red and Baltic Seas

The main aim of this study was to assess the hydrogen peroxide (HP) production rates (HPPR) related to anthropogenic pollution in coastal waters by laboratory and field experiments. HPPR's were assessed by simultaneous measurements of HP concentrations, cumulative solar UV irradiation and dissolved organic matter (DOM) fluorescence in the seawater samples at clean and polluted sites in the Mediterranean, Red and the Baltic Seas. The natural HP concentrations at all sites (8–100 nM) fall within the normal range recorded elsewhere, and follows a diurnal pattern. The polluted stations in the Mediterranean and Baltic Seas showed higher HPPR (3.2–16.6 nM m² W⁻¹ h⁻¹) than the clean stations, while in the Red Sea no significant differences were found because the station that was considered a priori polluted was actually rather clean (2–3 nM m² W⁻¹ h⁻¹). Laboratory experiments demonstrated that HPPR was positively linearly correlated to DOM fluorescence, however, this relationship was not found in the natural seawater samples examined in the field. The lack of relationship between HPPR and DOM in the field was attributed to enzymatic breakdown of HP as observed in dark decay experiments. HP dark decay rates were highest in polluted stations, probably due to larger bacterioplankton populations in these samples. Moreover, the HP dark decay rates were much lower in filtered than in non-filtered samples. Sun incubation of filtered (0.2 μm) seawater samples were performed to assess whether elimination of particles would yield higher HPPRs than in non-filtered samples. In the Baltic Sea (low UV irradiation) HPPR was higher in the filtered samples, while at sites with relatively high UV irradiation (Mediterranean and Red Seas), filtration of seawater did not stimulate HPPRs, probably due to UV-damage to planktonic microorganisms.     

A Parameterisation of the Effective Roughness Length over Inhomogeneous, Flat Terrain

A parameterisation ofthe effective roughness length is presented for an arbitrary givenroughness distribution z₀(x,y) over flat terrainat neutral stratification.Beyond pure averaging, it takes into account the spatial structure of the distribution, especially the influence of length scales, and inflow direction.To allow for interactions between different rough areas, Boussinesq-approximated equations with a turbulence closure of first order are considered and solved using perturbation theory.As a result, the logarithm of the effective roughness length isrepresented as a sum over the product of the Fourier transformation of log z₀ and a so-called dynamic function, which describesthe response of the flow field to a single wavelength of z₀.Although the numerical expenditure is larger than for simple averaging formulae,this method could be used by large-scale models to calculateeffective roughness lengths in every close-to-surface grid cell.     

Validation of ADEOS-II GLI ocean color products using in-situ observations

The Global Imager (GLI) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) made global observations from 2 April 2003 to 24 October 2003. In cooperation with several institutes and scientists, we obtained quality controlled match-ups between GLI products and in-situ data, 116 for chlorophyll-a concentration (CHLA), 249 for normalized water-leaving radiance (nLw) at 443 nm, and 201 for aerosol optical thickness at 865 nm (Tau_865) and Angstrom exponent between 520 and 865 nm (Angstrom). We evaluated the GLI ocean color products and investigated the causes of errors using the match-ups. The median absolute percentage differences (MedPD) between GLI and in-situ data were 14.1–35.7% for nLws at 380–565 nm, 52.5–74.8% nLws at 625–680 nm, 47.6% for Tau_865, 46.2% for Angstrom, and 46.6% for CHLA, values that are comparable to the ocean-color products of other sensors. We found that some errors in GLI products are correlated with observational conditions; nLw values were underestimated when nLw at 680 nm was high, CHLA was underestimated in absorptive aerosol conditions, and Tau_865 was overestimated in sunglint regions. The error correlations indicate that we need to improve the retrievals of the optical properties of absorptive aerosols and seawater and sea surface reflection for further applications, including coastal monitoring and the combined use of products from multiple sensors.     

When less is more: limits to international transfers under Article 6 of the Paris Agreement

International carbon markets can be an important tool in achieving countries’ mitigation targets under the Paris Agreement, but they are subject to a number of environmental integrity risks. An important risk is that some countries have mitigation targets that correspond to higher levels of emissions than independent projections of their likely emissions. If such ‘hot air’ can be transferred to other countries, it could increase aggregated emissions and create a perverse incentive for countries not to enhance the ambition of future mitigation targets. Limits to international transfers of mitigation outcomes have been proposed to address this risk. This article proposes a typology for such limits, explores key design options, and tests different types of limits in the context of 15 countries. Our analysis indicates that limits to international transfers could, if designed appropriately, prevent most of the hot air contained in current mitigation targets from being transferred, but also involve trade-offs between different policy objectives. Given the risks from international transfer of hot air and the uncertainty over whether other approaches will be effective in ensuring environmental integrity, we recommend that countries take a cautious approach and pursue a portfolio of approaches to ensure environmental integrity, in which case limits could provide for additional safeguards.

Key policy insights

• Limits to international transfers involve trade-offs between different policy objectives, in particular reducing the risk that countries transfer hot air and enabling participation in carbon markets.

• Under ‘relative’ limits a country may transfer mitigation outcomes to the extent that its actual emissions are below the limit. Relative limits derived from historical emissions data have significant limitations, and none of the tested approaches was found to be effective for all countries. Relative limits based on emission projections could be a more valid approach, although they are also technically and politically challenging.

• Under ‘absolute’ limits a country could only issue, transfer or acquire a certain amount of mitigation outcomes. Absolute limits set at sufficiently low levels could prevent countries from transferring large amounts of hot air, but are bluntly applicable to all countries, whether or not they have hot air.

     

Biostratigraphy of large benthic foraminifera from Hole U1468A (Maldives): a CT-scan taxonomic approach

Large benthic foraminifera are important components of tropical shallow water carbonates. Their structure, developed to host algal symbionts, can be extremely elaborate and presents stratigraphically-significant evolutionary patterns. Therefore their distribution is important in biostratigraphy, especially in the Indo-Pacific area. To provide a reliable age model for two intervals of IODP Hole U1468A from the Maldives Inner-Sea, large benthic foraminifera have been studied with computed tomography. This technique provided 3D models ideal for biometric-based identifications, allowing the upper interval to be placed in the late middle-Miocene and the lower interval in the late Oligocene.