Chapters in Books (Botany and Zoology)

Permanent URI for this collection


Recent Submissions

Now showing 1 - 2 of 2
  • Item
    Nutrient dynamics in the vicinity of the Prince Edward Islands
    (AFRICAN SUN MeDIA, 2008) Smith, Valdon R.; Froneman, P. William
    Nutrient concentrations in the open waters of the Polar Frontal Zone (PFZ) are highly variable, reflecting the region’s complex oceanographic regime. Surface concentrations of nitrate, silicate and phosphate range from 9.5 to 97.5, from 0.2 to 16.5 and from < 0.1 to 16.6 mmol m-3, respectively (Allanson et al. 1985; Duncombe Rae 1989; Ismail 1990; Balarin 2000). Changes in nutrient concentrations coincide with the intrusion of Antarctic surface water from the south and sub-Antarctic surface water from the north (Ansorge et al. 1999; Froneman et al. 1999). Mesoscale features such as far field eddies or the eddies generated by the interaction between the Antarctic Circumpolar Current (ACC) and the South-West Indian Ridge further contribute to the heterogeneity in nutrient concentrations within the surface waters of the PFZ (Ansorge & Lutjeharms 2002, 2003; Ansorge et al. 2004).
  • Item
    The Prince Edward Islands in a global context
    (AFRICAN SUN MeDIA, 2008) Chown, Steven L.; Froneman, P. William
    The history of the planet is one of change. Continental positions have moved, sea-levels have advanced and retreated, mountains have been formed and eroded, climates have varied from warm to cool and back again, and life has responded to and sometimes driven these processes, with species and higher taxa waxing and waning for the last several billion years (Stanley 1989; Behrensmeyer et al. 1992). More recently, humans have come to influence these changes. Our recent history has been one of significant effects on the abiotic environment, including elevation of atmospheric greenhouse gas concentrations, depletion of stratospheric ozone, and alterations to the global climate (Watson 2002; Domack et al. 2005). In turn, changing climates have had and continue to have profound effects on biodiversity, ranging from population and species loss (Pounds et al. 2006) to alterations in species distributions, changes in phenology, and shifts in ecological regimes (Walther et al. 2002; Parmesan & Yohe 2003; Root et al. 2003).