NITRATE-NITROGEN FLUX AND UTILIZATION IN A STREAM ECOSYSTEM DURING LOW SUMMER FLOWS

Analysis of nitrate transport in the downstream reaches of Duffin Creek, Ontario, revealed an average daily loss of 45 kg nitrate-N during low summer flows. The nitrate loss represents 50 per cent of the average daily input of total nitrogen and 75 per cent of the nitrate input received by these channel reaches. Nitrate uptake by benthic algae appears to account for a small portion of the NO₃^- removal. Laboratory experiments suggest that most of the nitrate disappearance from the river reaches is caused by bacterial denitrification and nitrate reduction in stream sediments.
L'analyse du transport de nitrate dans l'étendue en aval de Duffin Creek, Ontario, a révélé une perte journalière moyenne de 45 kg de nitrate-N durant l'écoulement affaibli des flots du ruisseau en été. Cette perte de nitrate représente 50 pourcent de la moyenne journalière du total d'azote fourni et 75 pourcent du nitrate reçu par l'étendue de ce canal. Les algues agrostides ne semblent être responsable que d'une faible partie de ladisparition du NO₃^-. Des experiences en laboratoire suggèrent que presque toute la disparition du nitrate dans la riviere est causée par la dénitrification bactérienne et la réduction d'azote dans les sédiments du cours d'eau.     

“Spreading the Wealth”: Justice Tom C. Clark's Wide‐ranging Efforts to Open the Doors of the Law Clerk Ranks

Associate Justice Tom C. Clark retired from the Supreme Court at the conclusion of its 1966 term to avoid even the appearance of impropriety when his son, Ramsey, became the U.S. Attorney General. “I believe it would be best for me to retire,” Clark wrote one well‐wisher, “Litigants have enough problems without having a father‐son psychology to face. And while there is no actual conflict the potential is there and the appearance of justice is as important and effective as the real thing.” ¹ Clark had served on the Court eighteen years, and he began his retirement with a three‐month, state‐sponsored goodwill trip around the world, which was cut short when he contracted hepatitis in Thailand.     

Britain and the British Antarctic Territory in the wider geopolitics of the Antarctic and the Southern Ocean

Britain's contemporary and future relationship with the British Antarctic Territory and the wider region is the subject matter of this article. In the aftermath of the ill‐fated plans for a merger of British Antarctic Survey (BAS) and the National Oceanography Centre, it is timely to ask how the UK projects influence and secures its scientific, resource and strategic interests. The contemporary Antarctic is increasingly characterized by tension over resource management and conservation politics as Antarctic Treaty parties disagree, both in private and public, over the purpose of legal instruments and the regulation of activities such as fishing and marine conservation. While we do not predict the collapse of the Antarctic Treaty System (ATS), our analysis suggests that the effectiveness and legitimacy of the ATS is increasingly under challenge. The United Kingdom's position as a claimant state and original signatory to the Antarctic Treaty is complicated by the presence of counter‐claimants (Argentina and Chile) and a wider preoccupation with other overseas territories, such as South Georgia and South Sandwich Islands and the Falkland Islands. Polar science, carried out by BAS and other British agents, remains critical not only for maintaining the UK's ‘soft power’ but also increasingly for cementing a ‘strategic presence’ in the Antarctic. The article ends with a cautionary note: scientific excellence is no longer sufficient to guarantee geopolitical/strategic interests and there is growing evidence that claimant and non‐claimant states alike are no longer regarding Antarctica as an area that will remain free of intensifying and diversifying resource exploitation.     

Ghettos in Canada's cities? Racial segregation,ethnic enclaves and poverty concentration in Canadian urban areas

Recent literature suggests a growing relationship between the clustering of certain visible minority groups in urban neighbourhoods and the spatial concentration of poverty in Canadian cities, raising the spectre of ghettoization. This paper examines whether urban ghettos along the U.S. model are forming in Canadian cities, using census data for 1991 and 2001 and borrowing a neighbourhood classification system specifically designed for comparing neighbourhoods in other countries to the U.S. situation. Ecological analysis is then performed in order to compare the importance of minority concentration, neighbourhood classification and housing stock attributes in improving our understanding of the spatial patterning of low-income populations in Canadian cities in 2001. The findings suggest that ghettoization along U.S. lines is not a factor in Canadian cities and that a high degree of racial concentration is not necessarily associated with greater neighbourhood poverty. On the other hand, the concentration of apartment housing, of visible minorities in general, and of a high level of racial diversity in particular, do help in accounting for the neighbourhood patterning of low income. We suggest that these findings result as much from growing income inequality within as between each visible minority group. This increases the odds of poor visible minorities of each group ending up in the lowest-cost, least-desirable neighbourhoods from which they cannot afford to escape (including social housing in the inner suburbs). By contrast, wealthier members of minority groups are more mobile and able to self-select into higher-status 'ethnic communities'. This research thus reinforces pleas for a more nuanced interpretation of segregation, ghettoization and neighbourhood dynamics.     

NITRATE-NITROGEN FLUX AND UTILIZATION IN A STREAM ECOSYSTEM DURING LOW SUMMER FLOWS

Analysis of nitrate transport in the downstream reaches of Duffin Creek, Ontario, revealed an average daily loss of 45 kg nitrate-N during low summer flows. The nitrate loss represents 50 per cent of the average daily input of total nitrogen and 75 per cent of the nitrate input received by these channel reaches. Nitrate uptake by benthic algae appears to account for a small portion of the NO₃^- removal. Laboratory experiments suggest that most of the nitrate disappearance from the river reaches is caused by bacterial denitrification and nitrate reduction in stream sediments. L'analyse du transport de nitrate dans l'étendue en aval de Duffin Creek, Ontario, a révélé une perte journalière moyenne de 45 kg de nitrate-N durant l'écoulement affaibli des flots du ruisseau en été. Cette perte de nitrate représente 50 pourcent de la moyenne journalière du total d'azote fourni et 75 pourcent du nitrate reçu par l'étendue de ce canal. Les algues agrostides ne semblent être responsable que d'une faible partie de ladisparition du NO₃^-. Des experiences en laboratoire suggèrent que presque toute la disparition du nitrate dans la riviere est causée par la dénitrification bactérienne et la réduction d'azote dans les sédiments du cours d'eau.