On request from Dr Ritchie we have developed and trialled our new leaf absorptance meter, the “Blue-RAT”, where RAT stands for Reflectance, Absorptance and Transmittance. The Blue-RAT was specifically designed to monitor fluorescence of bacteriochlorophyll which absorbs mostly blue light. White-RAT and Red-RAT versions are also available. see http://aquation.com.au/products/blue-rat-absorptance-meter
Dr Ray Ritchie has kindly allowed us to post his calculators on our website – see the Tools section. They take the form of spreadsheets, be sure to enable macros after downloading the file. Enjoy!
Aquation Director Dr John Runcie and colleague Dr Martin Riddle from the Australian Antarctic Division on the 15July2011 published a paper “Runcie, J.W., Riddle, M.J. (2011) Distinguishing downregulation from other non-photochemical quenching of an Antarctic benthic macroalga using in situ fluorometry”. European Journal of Phycology 46(3). 171-180, doi:10.1080/09670262.2011.584635.
The paper describes how automated dark-acclimation and measurement of photosynthetic organisms throughout the day can provide information describing both the extent and types of stress encountered over a 24 h period. The technique is useful in distinguishing natural stress (e.g. high light) from other forms of stress including anthropogenic pollution. Data collected for the paper was collected at Casey, one of Australia’s continental Antarctic Research Stations.
The quantum yield of chlorophyll a fluorescence of an Antarctic macroalga, Iridaea cordata, was measured in situ using logging fluorometers with an automated dark-acclimation capability throughout several diel periods. Application of far-red light and dark acclimation enabled the automated determination of photochemical quenching and non-photochemical quenching parameters that have until recently been restricted to manual measurement in terrestrial and shallow water environments. Our results show that non-photochemical quenching processes in Iridaea thalli that have been exposed to moderately high irradiances during the day, take all night to relax. We also show that, for algae exposed to relatively high light during the day, around 30–40% of total excitation flux is allocated to basal intrinsic non-radiative decay processes, with the remainder allocated to downregulation or photochemistry. The ability to evaluate the allocation of energy to these fundamentally different non-photochemical quenching processes has direct applications in assessing algal responses to both natural and anthropogenic stress. With this technology we open the door to a far more detailed examination of the regulation and kinetics of in situ photosynthesis and associated non-photochemical processes.
A PDF of the paper is available from the author on request: john.runcie “at” aquation.com.au
I have updated a lot of the website content including more images and a movie. The attached product files are next. So have a look around and come back again. If you need more information about any of our products or services, just send me an email: info@aquation.com.au. John
Aquation offers a range of specialist monitoring equipment for water, plant health and environmental testing applications. We can also custom design and build specialist scientific equipment.
Aquation comprises the experience and knowledge of a team of qualified and experienced water-quality management scientists.
We aim to provide optimal solutions for water quality monitoring problems by offering both a standard line of monitoring products and the option of developing a custom built system tailored for your specific requirements.
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