The great Sumatra-Andaman earthquake of 26 December 2004

The two largest earthquakes of the past 40 years ruptured a 1600-kilometer-long portion of the fault boundary between the Indo-Australian and southeastern Eurasian plates on 26 December 2004 [seismic moment magnitude (Mw) = 9.1 to 9.3] and 28 March 2005 (Mw = 8.6). The first event generated a tsunami that caused more than 283,000 deaths. Fault slip of up to 15 meters occurred near Banda Aceh, Sumatra, but to the north, along the Nicobar and Andaman Islands, rapid slip was much smaller. Tsunami and geodetic observations indicate that additional slow slip occurred in the north over a time scale of 50 minutes or longer.     

Simulation of subduction zone seismicity by dehydration of serpentine

We measured acoustic emission energy during antigorite dehydration in a multianvil press from 1.5 to 8.5 gigapascals and 300 degrees to 900 degrees C. There was a strong acoustic emission signal on dehydration, and analysis of recovered samples revealed brittle deformation features associated with high pore-fluid pressures. These results demonstrate that intermediate depth (50 to 200 kilometers) seismicity can be generated by dehydration reactions in the subducting slab.     

Laboratory simulation of volcano seismicity

The physical processes generating seismicity within volcanic edifices are highly complex and not fully understood. We report results from a laboratory experiment in which basalt from Mount Etna volcano (Italy) was deformed and fractured. The experiment was monitored with an array of transducers around the sample to permit full-waveform capture, location, and analysis of microseismic events. Rapid post-failure decompression of the water-filled pore volume and damage zone triggered many low-frequency events, analogous to volcanic long-period seismicity. The low frequencies were associated with pore fluid decompression and were located in the damage zone in the fractured sample; these events exhibited a weak component of shear (double-couple) slip, consistent with fluid-driven events occurring beneath active volcanoes.     

Is the decline of freshwater mussel populations in a regulated coastal river in south‐eastern Australia linked with human modification of habitat?

• 1. The Hawkesbury‐Nepean River provides potable water for 5 million people living in the Sydney basin, and water for agricultural and horticultural production that meets most of Sydney's daily needs for fresh food. Anecdotal evidence indicated that numbers of freshwater mussels have seriously declined in much of the river over recent decades.
• 2. A field survey revealed the presence of populations of three species of mussels, Hyridella depressa, Hyridella australis and Velesunio ambiguus in the river. Higher density mussel populations were most common in catchment areas with little human modification to the channel bed or adjacent vegetation communities.
• 3. Levels of disturbance of riparian vegetation and, to a lesser degree, land use, were identified as being strongly associated with the absence of mussels from some reaches.
• 4. Catchment geomorphology was also shown to be relevant to the abundance, population structure and suite of mussel species present in different geomorphic reaches of the river. Absence of mussels was noted from areas where they had been recorded in previous studies. These results demonstrate that mussel species are under threat in the catchment.
• 5. As filter feeders with the ability to remove excess nutrients and bioaccumulate toxic substances, freshwater mussels play an important role in natural remediation processes in freshwater systems.
• 6. The decline in mussel populations in the Hawkesbury‐Nepean River highlights concerns for the overall health of the river system, and supports the need to identify the subsidiary impacts of physical habitat modification in developing both riverine and riparian management strategies.

Copyright © 2006 John Wiley & Sons, Ltd.     

Brandt's cormorant diet (1994–2012) indicates the importance of fall ocean conditions for northern anchovy in central California

Effective ecosystem‐based management requires a comprehensive understanding of the functional links in the system. In many marine systems, forage species constitute a critical link between primary production and upper trophic level marine predators. As top predators, seabirds can be indicators of the forage species they consume and the ocean processes that influence these populations. We analyzed the diet and breeding success for the years 1994, 2003, 2005, and 2007–2012 of the Brandt's cormorant (Phalacrocorax penicillatus), a piscivorous diving seabird, breeding in central California, to evaluate the extent to which cormorant diet composition relates to prey availability, and how diet composition relates to breeding success and ocean conditions. Cormorant diet was primarily composed of young‐of‐the‐year (YOY) northern anchovy (Engraulis mordax), YOY rockfish (Sebastes spp.), and several species of small flatfish (order Pleuronectiformes). YOY rockfish consumption was positively related to their abundance as measured in a late spring pelagic midwater trawl survey. Northern anchovy appeared to be the most important prey as its consumption was positively related to cormorant breeding success. More northern anchovy were consumed in years where warm‐water conditions prevailed in the fall season before cormorant breeding. Thus, warm ocean conditions in the fall appear to be an important contributing factor in producing a strong year‐class of northern anchovy in central California and consequently a strong‐year class of Brandt's cormorant on the Farallon Islands.     

Ultrasonographic and laboratory screening in clinically normal mature golden retriever dogs

Wellness and pre-anesthetic screening of blood and urine of geriatric companion animals are routinely recommended. In addition, there are occasional references to the use of imaging in clinically normal geriatric patients. However, the utility of wellness testing is not known, and there is limited information regarding the value of pre-anesthetic testing. Wellness testing, including complete blood cell count, biochemical profile, urinalysis, and abdominal ultrasound, was performed on 53 clinically normal, mature golden retriever dogs. Laboratory analysis revealed abnormalities in 54.7% (29/53) of the dogs. Abdominal ultrasound screening demonstrated abnormalities in 64.2% (34/53) of the dogs. As only a small number of dogs had follow-up diagnostic testing available, the significance of these abnormalities is unknown. Further study involving a larger cohort of animals and analysis of follow-up data is necessary to determine the utility of laboratory and imaging studies in clinically normal geriatric patients.