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.

Evidence for the accelerations of sea level on multi-decade and century timescales.

Abstract: A modification in the rate of change of sea level (i.e. an ‘acceleration’ or ‘nonlinear trend’) is an important climate-related signal, which requires confirmation and explanation. In this study, the evidence for accelerations in regional and global average sea level on timescales of several decades and longer is reviewed by inter-comparison of the recent findings of different researchers and by inspection of original tide gauge records. Most sea-level data originate from Europe and North America, and both the sets display evidence for a positive acceleration, or ‘inflexion’, around 1920–1930 and a negative one around 1960. These inflexions are the main contributors to reported accelerations since the late 19th century, and to decelerations during the mid- to late 20th century. However, these characteristic features are not always found in records from other parts of the world. Although some aspects of the sea-level time series are consistent with changes in rates of globally averaged temperature changes, volcanic eruptions and natural climate variability, modelling undertaken so far has been unable to describe these features adequately. This emphasizes the need for a major enhancement of the sea-level data set, especially for those parts of the world without long tide gauge records, in order to obtain greater insight into the spatial dependence of accelerations. A number of complementary methods must be employed, of which salt marsh techniques offer the possibility of obtaining time series similar to those that would have been obtained from coastal tide gauges. Copyright © 2008 Royal Meteorological Society

Cyanobacterial poisoning in livestock, wild mammals and birds--an overview.

Abstract: Poisoning of livestock by toxic cyanobacteria was first reported in the 19th century, and throughout the 20th century cyanobacteria–related poisonings of livestock and wildlife in all continents have been described. Some mass mortality events involving unrelated fauna in prehistoric times have also been attributed to cyanotoxin poisoning; if correct, this serves as a reminder that toxic cyanobacteria blooms predate anthropogenic manipulation of the environment, though there is probably general agreement that human intervention has led to increases in the frequency and extent of cyanobacteria blooms. Many of the early reports of cyanobacteria poisoning were anecdotal and circumstantial, albeit with good descriptions of the appearance and behaviour of cyanobacteria blooms that preceded or coincided with illness and death in exposed animals. Early necropsy findings of hepatotoxicity were subsequently confirmed by experimental investigations. More recent reports supplement clinical and post–mortem findings with investigative chemistry techniques to identify cyanotoxins in stomach contents and tissue fluids.

Numerical Modeling of Gravity Wave Generation by Deep Tropical Convection

Abstract: Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep convection over the Tiwi Islands, Australia. The numerical calculations presented explicitly resolve both the mesoscale convective cloud cluster and the gravity waves generated. As the convective clouds evolve, they excite gravity waves, which are prominent features of the model solutions in both the troposphere and stratosphere. The source location is variable in time and space but is related to the development of individual convective cells. The largest amplitude gravity waves are generated when the cloud tops reach the upper troposphere. A new analysis technique is introduced in which the nonlinear terms in the governing equations are taken as the forcing for linear gravity waves. The analysis shows that in the present calculation, neither the shear nor the diabatic heating are the dominant forcing terms. Instead, the wave source is most easily understood when viewed in a frame of reference moving with the wind at the level of neutral buoyancy, whereupon the source may be described as a vertically oriented, oscillating convective updraft. This description is consistent with the properties of the modeled stratospheric waves.

Southern Ocean phytoplankton in a changing climate

Abstract: Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.