13 research outputs found
Observations of severe hypoxia and offshore displacement of cape hake over the Namibian shelf in 1994
In 1994, persistent and pronounced hypoxic conditions developed off the coast of central and northern Namibia, with oxygen level
Annual changes in serum calcium and inorganic phosphate levels and correlation with gonadal status of a freshwater murrel, Channa punctatus (Bloch)
Adult Channa punctatus murrels of both sexes (60-80 g) were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month) throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960) and Fiske and Subbarow (1925), respectively. Gonads were fixed to judge the state of maturation of the fish. Males exhibited no change in serum calcium levels throughout the year in correlation with testicular maturation. However, serum phosphate levels exhibited a rise in correlation with the increased gonadosomatic index. Females showed marked seasonal changes in serum calcium and phosphate levels which were associated with ovarian maturation (vitellogenesis)
The Capricorn Eddy: A prominent driver of the ecology and future of the southern Great Barrier Reef
This study focuses on a mesoscale eddy feature, the 'Capricorn Eddy', that typically forms within an indentation of the continental shelf in the southern GBR system. Satellite data at moderate resolution (1 km) are used to examine relevant mesoscale and sub-mesoscale sea surface dynamics. Available in situ measurements and model data are used to validate the satellite observations and to specify the nature of the processes occurring within the water column itself. The characteristic features are identified and physical theory employed to develop an understanding of associated processes. In particular, the effect of the eddy in raising cooler, nutrient-enriched oceanic subsurface water and transporting it to the reef zone, and eventually into the lagoon, is shown. This study demonstrates that the linkages between large-scale oceanography and the meso- and sub-mesoscale patterns are crucial to determining biologic responses on the scale of reef communities and may be key to understanding climate change impacts at the relevant spatial scales. © 2010 The Author(s)