Cooperative Research Centre

About: Cooperative Research Centre is a based out in . It is known for research contribution in the topics: Population & Sea ice. The organization has 7633 authors who have published 8607 publications receiving 429721 citations.

River regulation and fish communities in the Murray-Darling River system, Australia

Abstract: Fish communities from four catchments in the Murray—Darling river system were analysed in relation to climate, hydrology and river regulation. Using the annual proportional flow deviation as a measure of river regulation, the Paroo River catchment was assessed as unregulated, the Darling River catchment as mildly regulated and the Murrumbidgee River and River Murray catchments as highly regulated. A total of 11010 fish, representing nine native and three alien species, was caught during high and low flow seasons in the four catchments. Native species, such as golden perch Macquaria ambigua (Percichthyidae), bony herring Nematalosa erebi (Clupeidae) and spangled perch Leiopotherapon unicolor (Teraponidae), dominated fish communities in the Paroo and Darling catchments, but alien species, mostly carp, Cyprinus carpio (Cyprinidae), were also abundant. Both native and alien species were more abundant in these catchments after flooding, but there was little change in species composition between high and low flow seasons at the catchment level. Carp dominated communities in the Murray and Murrumbidgee catchments. There was a significant trend for reduced species diversity in increasingly regulated catchments. River regulation may alter the relative abundance of native and alien fish by desynchronizing environmental cycles and the reproductive cycles of native species. Ordination of species abundances showed discrete fish communities that reflect the geographical separation between catchments. Differences between communities are related to opportunities for dispersal, the environmental tolerances of dominant species and the modifying effects of river regulation. Fish communities in lakes exhibited less seasonal variation than riverine communities within the same catchment, indicating the greater seasonal stability of lakes compared with regulated and unregulated river reaches. Management of fish resources needs to include catchment-specific strategies within current State and basin-wide management programmes.

Understanding variability in winegrape production systems 2. Within vineyard variation in quality over several vintages

Abstract: Spatial variability in various indices of wine grape quality was studied over several vintages in blocks planted to Cabernet Sauvignon and Ruby Cabernet in the Coonawarra (1999-2002) and Sunraysia (2000-2002) regions of Australia. At both sites, intra-annual variation was marked whilst intra-annual variation was much greater for some indices (e.g. concentration of total phenolics) than others (e.g. Baume). The magnitude of intra-annual variation was readily identified in terms of the 'spread', defined as the difference between the maximum and minimum values, expressed as a % of the median value. Typical values of the spread were 20% for Baume, but could be as high as 117% for phenolics, and better indicated the extent of variation facing the winemaker than the coefficient of variation (CV; typically 3% for Baume and l4% for phenolics). For all attributes, variation in any given year showed marked spatial structure, with the patterns of variation being broadly consistent for each attribute in each year of the study, and with many attributes following similar patterns. The results therefore strongly support the idea of zonal vineyard management. However, fruit quality zone identification is dependent on a large sampling effort. Therefore, given the current availability of yield monitors, the finding that between-zone differences in quality indices were generally significant (P < 0.05) for zones identified on the basis ob yield alone, and, in the absence ob an on-the-go sensing capability, it is suggested that zonal management should proceed on the basis of zones ob characteristic yield productivity. Based on the present work, it is suggested that development ob an on-the-go fruit quality sensing technology would enable the wine industry co maximise its opportunity to gain benefit from differential vineyard management such as selective harvesting. Indeed, the results ob this work suggest that in the absence ob zonal management, preferably supported by on-the-go quality sensing, winemaker demands for delivery of uniform parcels of fruit are unlikely to be satisfied.

Old radiocarbon ages in the southwest Pacific Ocean during the last glacial period and deglaciation

Abstract: Marine radiocarbon (14C) dates are widely used for dating oceanic events and as tracers of ocean circulation, essential components for understanding ocean-climate interactions. Past ocean ventilation rates have been determined by the difference between radiocarbon ages of deep-water and surface-water reservoirs, but the apparent age of surface waters (currently approximately 400 years in the tropics and approximately 1,200 years in Antarctic waters) might not be constant through time, as has been assumed in radiocarbon chronologies and palaeoclimate studies. Here we present independent estimates of surface-water and deep-water reservoir ages in the New Zealand region since the last glacial period, using volcanic ejecta (tephras) deposited in both marine and terrestrial sediments as stratigraphic markers. Compared to present-day values, surface-reservoir ages from 11,900 14C years ago were twice as large (800 years) and during glacial times were five times as large (2,000 years), contradicting the assumption of constant surface age. Furthermore, the ages of glacial deep-water reservoirs were much older (3,000-5,000 years). The increase in surface-to-deep water age differences in the glacial Southern Ocean suggests that there was decreased ocean ventilation during this period.

Biological responses to the press and pulse of climate trends and extreme events

Abstract: The interaction of gradual climate trends and extreme weather events since the turn of the century has triggered complex and, in some cases, catastrophic ecological responses around the world. We illustrate this using Australian examples within a press–pulse framework. Despite the Australian biota being adapted to high natural climate variability, recent combinations of climatic presses and pulses have led to population collapses, loss of relictual communities and shifts into novel ecosystems. These changes have been sudden and unpredictable, and may represent permanent transitions to new ecosystem states without adaptive management interventions. The press–pulse framework helps illuminate biological responses to climate change, grounds debate about suitable management interventions and highlights possible consequences of (non-) intervention.

Speech Perception as a Function of Electrical Stimulation Rate: Using the Nucleus 24 Cochlear Implant System

Abstract: This is a publisher’s version of an article published in Ear and Hearing 2000. This version is reproduced with permission of Lippincott Wilkins & Williams.