Volunteered Geographic Information: A Bicycling Enthusiast Perspective

Mapping technologies have made considerable strides in recent decades. Global positioning systems (GPS), remote sensing satellites, Web-based mapping services, and geographic information systems (GIS) have facilitated the collection, distribution, analysis, and ultimately interaction with geospatial information. In particular, portable GPS have altered how individuals participate in mapping. Individuals can use GPS to collect tracings of their personal interactions with the environment. These interactions can then be uploaded to one of many available Web-based mapping services. Once uploaded, the geospatial data can be mapped and shared among the broader community of users. Such volunteered geographic information (VGI) exemplifies the conceptualization of an individual collecting, mapping, and sharing personal geographic information. This paper focuses on challenges surrounding VGI. To help place these challenges in a broader context, specialized Web services and GPS technologies developed for the bicycling community will serve as examples of the current status and future prospects of VGI.     

Application of a fat staging technique to examine temporal and spatial variability in lipid content of southern Benguela sardine Sardinops sagax

A recently developed technique to estimate the lipid content of pelagic fish, using macroscopic visual assessment of their mesenteric fat, was applied to samples of southern Benguela sardine Sardinops sagax collected from commercial catches over the period 1996–2004. The data were analysed using general linear modelling, and temporal and spatial variably in lipid content was examined and compared with that of condition factor derived from length/mass relationships. Lipid content showed a clear seasonal cycle, being highest in May and lowest in August. This pattern was comparable with seasonal cycles in condition factor, although lipid content peaked 1–5 months later than did condition factor. A strong spatial effect was apparent in model results, with both lipid content and condition factor being highest in sardine from the South-East Coast. The correspondence in results from the fat staging technique, and those derived using condition-factor data for longer time-series, validate the new technique, and the higher level of resolution of the former compared with the latter argue for broader application of this technique.     

Life strategies,energetics and growth characteristics of Calanoides carinatus (Copepoda) in the Angola-Benguela frontal region

Rates of daily egg production, moulting and egg hatching success, as well as total lipid content and composition of Calanoides carinatus, were measured in the region of the southern Angola Curre nt SAC), the Angola-Benguela Front (ABF) and the coastal upwelling area of the northern Benguela Current (NBC) system during February–March 2002. There were distinct differences in the vertical distribution, growth characteristics, lipid content and composition of populations in the SAC/ABF and NBC regions, indicative of different physiological states. Whereas in the NBC, C. carinatus was actively growing in response to elevated chlorophyll a levels associated with coastal upwelling, it comprised deep-living C5 copepodids with very large wax ester reseves (c. 40–50% dry mass) and extremely low metabolism in the SAC/ABF, suggesting diapause. This study provides the first data on lipid composition (lipid classes, fatty acids and alcohols) of this copepod in the region; in particular, the diapausing C5 contained high-levels of long-chain, mono-unsaturated fatty acids (23% of all fatty acids) and alcohols (69% of all fatty alcohols) in addition to trophic markers of diatoms, viz. 16:1(n-7) and 20:5(n-3). Based on total lipidcontent, the maximum survival time of the diapausal component of C. carinatus was estimated to be 149–192 days, whereas active surface-dwelling C5s and females could not survive for more than 10 days without feeding.