. A more accurate way to calculate power output from wind turbines based on fundamental Newtonian... more . A more accurate way to calculate power output from wind turbines based on fundamental Newtonian mechanics is proposed for testing. This contrasts with current methods regarded as governed by flows of kinetic energy through an area swept by rotating airfoils. Action mechanics measures torques caused by conservation of momentum of impulsive air streams on rotor surfaces at differing radii. We integrate the windward torque using inputs of rotor dimensions, the angle of incidence and strength of wind impulses on the blade surfaces. A reverse torque in the plane of rotation is estimated as radial impulses from the blade’s rotation. Net torque is converted to power by the angular velocity of the turbine rotors. A matter of concern is significant heat production by wind turbines, partly from leeward reactions but mainly from turbulent release of vortical energy. Use of wind farms as sources of renewable energy may need better practice, minimizing environmental impacts guided by this hypothesis.
A Reflectance Absorptance Transmittance (RAT) meter, developed for routine measurements of Abtλ n... more A Reflectance Absorptance Transmittance (RAT) meter, developed for routine measurements of Abtλ nm on leaves, was used to measure absorptance of algal films mounted on glass fibre filter disks for use in PAM (Pulse Amplitude Modulation) fluorometry. Absorptance readings (Abtλ nm) are essential to quantitate the photosynthetic electron transport rate from PAM data and are also helpful if algal disks are used in an IRGA (InfraRed Gas Analyzer). Measurements were made on Synechococcus R-2 (Cyanophyceae), Acaryochloris marina (Chlorobacteria), Chlorella vulgaris (Chlorophyceae), Chaetoceros sp. (Bacillariophyceae) and Isochrysis sp. (Haptophyta) in blue (445 nm), green (525 nm) and red (625 nm) light. Plots of Abtλ vs. Chl a (mg Chl a m-2) or Chl d for Acaryochloris (mg Chl d m-2) of the algae followed exponential saturation curves (Abt%λ = Abt%λ, ∞ (1-e-k×Chl)) usually reaching asymptotes in the blue light used by blue-diode PAM machines. Synechococcus, Chlorella, Chaetoceros and Isoch...
A novel method for calculating power output from wind turbines using Newtonian mechanics is propo... more A novel method for calculating power output from wind turbines using Newtonian mechanics is proposed. This contrasts with current methods based on interception rates by aerofoils of kinetic energy to estimate power output, governed by the Betz limit of propeller theory. Radial action [mrωrδφ =@, J.sec] generates torques from impulses from air molecules at differing radii on rotor surfaces, both windward and leeward. Dimensionally, torque is a rate of action [(mrωδφ)/δt, MLT, Nm]. Integration of the windward torque [Tw, Nm] is achieved numerically using inputs of rotor dimensions, the angle of incidence (θ) of elastic wind impulse [δMv] on the blade surface, chord and blade lengths and the tip-speed ratio with wind speed. The rate of leeward or back torque [Tb , Nm] in the plane of rotation is estimated from radial impulses from the blade’s rotation on material particles, with magnitude varying with the square of the blade radius and its angular velocity. The net torque (Tw Tb) from ...
pH, salinity, temperature and some pCO2 data collected in Sydney Harbour at the Sydney Institute ... more pH, salinity, temperature and some pCO2 data collected in Sydney Harbour at the Sydney Institute of Marine Sciences facility at Chowder Bay. The pH data is derived from a fluorescence-based measuring technique. The dataset consists of two Microsoft Excel spreadsheets, each containing multiple worksheets. The first spreadsheet, titled Runcie et al. 2018 April2016 data.xlsx, contains data derived from experiments run at Chowder Bay, NSW, Australia, in April 2016. Measurements were taken from water pumped from approximately 1-2m depth to 2-3m above water level. Water was debubbled and run through a clear tube, fluorescence spots were installed on the inside of this tube for measuring pH and pCO2. Temperature was measured from water in the debubbler chamber prior to the measuring tubes. Flow through rates were high to minimise a temperature difference between measured water and the bulk seawater. The second spreadsheet, titled Runcie et al. 2018 December 2016 dataset.xlsx, contains data...
Highlights • We provide a strategic review of research gaps for Australian seagrass ecosystems • ... more Highlights • We provide a strategic review of research gaps for Australian seagrass ecosystems • Priorities areas were identified at a workshop of seagrass experts • Forty key knowledge gaps were identified across ten research fields • This review provides a platform for a coordinated approach to seagrass research and management
Australian researchers in marine biodiversity and ecosystem science have a disproportionally high... more Australian researchers in marine biodiversity and ecosystem science have a disproportionally high impact on global research as measured by their number of publications and their high profile leadership of international initiatives. At least 170 researchers from over 32 institutions contributed to this research which has a high uptake in government agencies and industries as this topic area is the basis from which the impact of human development is measured. Despite this, we know surprisingly little of our marine environment – only 5.2% of the seafloor in Australia's Commonwealth Marine Reserve network has been mapped to acceptable precision, and only about 10% of marine species has been identified. In order to improve and assess marine management initiatives in light of funding accountability, marine biodiversity and ecosystem research needs to be prioritized to fill the knowledge gaps that would have most impact on the diverse set of marine stakeholders. For example, monitoring...
Ocean acidification (OA) is predicted to alter benthic marine community structure and function, h... more Ocean acidification (OA) is predicted to alter benthic marine community structure and function, however, there is a paucity of field experiments in benthic soft sediment communities and ecosystems. Benthic diatoms are important components of Antarctic coastal ecosystems, however very little is known of how they will respond to ocean acidification. Ocean acidification conditions were maintained by incremental computer controlled addition of high fCo 2 seawater representing OA conditions predicted for the year 2100. Respiration chambers and PAM fluorescence techniques were used to investigate acute behavioural, photosynthetic and net production responses of benthic microalgae communities to oA in in-situ field experiments. We demonstrate how OA can modify behavioural ecology, which changes photo-physiology and net production of benthic microalgae. Ocean acidification treatments significantly altered behavioural ecology, which in turn altered photophysiology. The ecological trends presented here have the potential to manifest into significant ecological change over longer time periods.
Electrical conductivity (salinity), temperature and fluorescence-based measurements of pH were em... more Electrical conductivity (salinity), temperature and fluorescence-based measurements of pH were employed to examine diel fluctuations in seawater carbonate chemistry of surface waters in Sydney Harbour over two multiple-day 10 periods. The fluorescence-based technique provided a useful time-series for pH. Alkalinity with pH and temperature were used to calculate the degree of aragonite and calcite saturation (Ca and Ar respectively). Alkalinity was determined from an alkalinity-salinity relationship. Variation in pH over minute-to hour-long periods was distinguishable from background variability. Diel variability in pH, ara and cal showed a clear pattern that appeared to correlate with both salinity and temperature. Drift due to photodegradation of the fluorophore was minimised by reducing exposure to ambient light. Ca 15 and Ar fluctuated approximately on a daily cycle. The net result of changes in pH, salinity and temperature combined to influence seawater carbonate chemistry. The fluorescence-based pH monitoring technique is simple, provides good resolution and is unaffected by moving parts or leaching of solutions over time. The use of optics is pressure insensitive, making this approach to ocean acidification monitoring well suited to deepwater applications.
Here we present the results of a multiple organizational level analysis conceived to identify acc... more Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between...
The quantum yield of photosystem II (φ II , also termed ΔF /F m ' or F v /F m in light-or darkacc... more The quantum yield of photosystem II (φ II , also termed ΔF /F m ' or F v /F m in light-or darkacclimated plants, respectively) of the tropical seagrass Halophila stipulacea was measured in situ using modulated fluorescence techniques over diel periods at a range of depths. Photosynthetic electron transport rates (ETRs), as derived from φ II values at specific ambient photosynthetically available radiation (PAR) irradiances, increased in direct proportion to increasing irradiance in the morning and, at shallow sites (7 to 10 m), reached saturating rates and then declined in the afternoon with lower PAR-specific ETRs. On the other hand, plants at 32 to 33 m showed no saturation even at midday, and the percentage reduction in PAR-specific afternoon ETRs was less than that of the shallower plants. The use of an automated shutter in the measuring device enabled non-photochemical quenching due to down-regulation and basal intrinsic non-radiative decay to be distinguished. While midday values of down-regulation were lower in deeper water, basal intrinsic non-radioactive decay remained fairly constant at 30 to 40% at all depths, with more variation in shallow waters. The maximal φ II (i.e. F v /F m ) reached similar values at midnight regardless of depth. H. stipulacea acclimates to the widely varying irradiances across this depth gradient by regularly modulating down-regulationbased non-photochemical quenching processes, while dissipating a large proportion of light energy through intrinsic decay regardless of depth.
Direct comparisons between photosynthetic O 2 evolution rate and electron transport rate (ETR) we... more Direct comparisons between photosynthetic O 2 evolution rate and electron transport rate (ETR) were made in situ over 24 h using the benthic macroalga Ulva lactuca (Chlorophyta), growing and measured at a depth of 1.8 m, where the midday irradiance rose to 400-600 µmol photons m −2 s −1 . O 2 exchange was measured with a 5-chamber data-logging apparatus and ETR with a submersible pulse amplitude modulated (PAM) fluorometer (Diving-PAM). Steady-state quantum yield ((F m −F t )/F m ) decreased from 0.7 during the morning to 0.45 at midday, followed by some recovery in the late afternoon. At low to medium irradiances (0-300 µmol photons m −2 s −1 ), there was a significant correlation between O 2 evolution and ETR, but at higher irradiances, ETR continued to increase steadily, while O 2 evolution tended towards an asymptote. However at high irradiance levels (600-1200 µmol photons m −2 s −1 ) ETR was significantly lowered. Two methods of measuring ETR, based on either diel ambient light levels and fluorescence yields or rapid light curves, gave similar results at low to moderate irradiance levels. Nutrient enrichment (increases in [NO 3 − ], [NH 4 + ] and [HPO 4 2− ] of 5-to 15-fold over ambient concentrations) resulted in an increase, within hours, in photosynthetic rates measured by both ETR and O 2 evolution techniques. At low irradiances, approximately 6.5 to 8.2 electrons passed through PS II during the evolution of one molecule of O 2 , i.e., up to twice the theoretical minimum number of four. However, in nutrient-enriched treatments this ratio dropped to 5.1. The results indicate that PAM fluorescence can be used as a good indication of the photosynthetic rate only at low to medium irradiances.
... The primary column was 15m0.32mmi.d. x0.25mm DBI701 (J and W Scientific) with hydrogen at 41 ... more ... The primary column was 15m0.32mmi.d. x0.25mm DBI701 (J and W Scientific) with hydrogen at 41 369 N m 2 as the carrier gas. ... et al., 1983 Subramanian et al., 1983 Subramanian et al., 1983 De Kock and Boshoff, 1987 De Kock and Boshoff, 1987 E1 Nabawi et al., 1987 El ...
. A more accurate way to calculate power output from wind turbines based on fundamental Newtonian... more . A more accurate way to calculate power output from wind turbines based on fundamental Newtonian mechanics is proposed for testing. This contrasts with current methods regarded as governed by flows of kinetic energy through an area swept by rotating airfoils. Action mechanics measures torques caused by conservation of momentum of impulsive air streams on rotor surfaces at differing radii. We integrate the windward torque using inputs of rotor dimensions, the angle of incidence and strength of wind impulses on the blade surfaces. A reverse torque in the plane of rotation is estimated as radial impulses from the blade’s rotation. Net torque is converted to power by the angular velocity of the turbine rotors. A matter of concern is significant heat production by wind turbines, partly from leeward reactions but mainly from turbulent release of vortical energy. Use of wind farms as sources of renewable energy may need better practice, minimizing environmental impacts guided by this hypothesis.
A Reflectance Absorptance Transmittance (RAT) meter, developed for routine measurements of Abtλ n... more A Reflectance Absorptance Transmittance (RAT) meter, developed for routine measurements of Abtλ nm on leaves, was used to measure absorptance of algal films mounted on glass fibre filter disks for use in PAM (Pulse Amplitude Modulation) fluorometry. Absorptance readings (Abtλ nm) are essential to quantitate the photosynthetic electron transport rate from PAM data and are also helpful if algal disks are used in an IRGA (InfraRed Gas Analyzer). Measurements were made on Synechococcus R-2 (Cyanophyceae), Acaryochloris marina (Chlorobacteria), Chlorella vulgaris (Chlorophyceae), Chaetoceros sp. (Bacillariophyceae) and Isochrysis sp. (Haptophyta) in blue (445 nm), green (525 nm) and red (625 nm) light. Plots of Abtλ vs. Chl a (mg Chl a m-2) or Chl d for Acaryochloris (mg Chl d m-2) of the algae followed exponential saturation curves (Abt%λ = Abt%λ, ∞ (1-e-k×Chl)) usually reaching asymptotes in the blue light used by blue-diode PAM machines. Synechococcus, Chlorella, Chaetoceros and Isoch...
A novel method for calculating power output from wind turbines using Newtonian mechanics is propo... more A novel method for calculating power output from wind turbines using Newtonian mechanics is proposed. This contrasts with current methods based on interception rates by aerofoils of kinetic energy to estimate power output, governed by the Betz limit of propeller theory. Radial action [mrωrδφ =@, J.sec] generates torques from impulses from air molecules at differing radii on rotor surfaces, both windward and leeward. Dimensionally, torque is a rate of action [(mrωδφ)/δt, MLT, Nm]. Integration of the windward torque [Tw, Nm] is achieved numerically using inputs of rotor dimensions, the angle of incidence (θ) of elastic wind impulse [δMv] on the blade surface, chord and blade lengths and the tip-speed ratio with wind speed. The rate of leeward or back torque [Tb , Nm] in the plane of rotation is estimated from radial impulses from the blade’s rotation on material particles, with magnitude varying with the square of the blade radius and its angular velocity. The net torque (Tw Tb) from ...
pH, salinity, temperature and some pCO2 data collected in Sydney Harbour at the Sydney Institute ... more pH, salinity, temperature and some pCO2 data collected in Sydney Harbour at the Sydney Institute of Marine Sciences facility at Chowder Bay. The pH data is derived from a fluorescence-based measuring technique. The dataset consists of two Microsoft Excel spreadsheets, each containing multiple worksheets. The first spreadsheet, titled Runcie et al. 2018 April2016 data.xlsx, contains data derived from experiments run at Chowder Bay, NSW, Australia, in April 2016. Measurements were taken from water pumped from approximately 1-2m depth to 2-3m above water level. Water was debubbled and run through a clear tube, fluorescence spots were installed on the inside of this tube for measuring pH and pCO2. Temperature was measured from water in the debubbler chamber prior to the measuring tubes. Flow through rates were high to minimise a temperature difference between measured water and the bulk seawater. The second spreadsheet, titled Runcie et al. 2018 December 2016 dataset.xlsx, contains data...
Highlights • We provide a strategic review of research gaps for Australian seagrass ecosystems • ... more Highlights • We provide a strategic review of research gaps for Australian seagrass ecosystems • Priorities areas were identified at a workshop of seagrass experts • Forty key knowledge gaps were identified across ten research fields • This review provides a platform for a coordinated approach to seagrass research and management
Australian researchers in marine biodiversity and ecosystem science have a disproportionally high... more Australian researchers in marine biodiversity and ecosystem science have a disproportionally high impact on global research as measured by their number of publications and their high profile leadership of international initiatives. At least 170 researchers from over 32 institutions contributed to this research which has a high uptake in government agencies and industries as this topic area is the basis from which the impact of human development is measured. Despite this, we know surprisingly little of our marine environment – only 5.2% of the seafloor in Australia's Commonwealth Marine Reserve network has been mapped to acceptable precision, and only about 10% of marine species has been identified. In order to improve and assess marine management initiatives in light of funding accountability, marine biodiversity and ecosystem research needs to be prioritized to fill the knowledge gaps that would have most impact on the diverse set of marine stakeholders. For example, monitoring...
Ocean acidification (OA) is predicted to alter benthic marine community structure and function, h... more Ocean acidification (OA) is predicted to alter benthic marine community structure and function, however, there is a paucity of field experiments in benthic soft sediment communities and ecosystems. Benthic diatoms are important components of Antarctic coastal ecosystems, however very little is known of how they will respond to ocean acidification. Ocean acidification conditions were maintained by incremental computer controlled addition of high fCo 2 seawater representing OA conditions predicted for the year 2100. Respiration chambers and PAM fluorescence techniques were used to investigate acute behavioural, photosynthetic and net production responses of benthic microalgae communities to oA in in-situ field experiments. We demonstrate how OA can modify behavioural ecology, which changes photo-physiology and net production of benthic microalgae. Ocean acidification treatments significantly altered behavioural ecology, which in turn altered photophysiology. The ecological trends presented here have the potential to manifest into significant ecological change over longer time periods.
Electrical conductivity (salinity), temperature and fluorescence-based measurements of pH were em... more Electrical conductivity (salinity), temperature and fluorescence-based measurements of pH were employed to examine diel fluctuations in seawater carbonate chemistry of surface waters in Sydney Harbour over two multiple-day 10 periods. The fluorescence-based technique provided a useful time-series for pH. Alkalinity with pH and temperature were used to calculate the degree of aragonite and calcite saturation (Ca and Ar respectively). Alkalinity was determined from an alkalinity-salinity relationship. Variation in pH over minute-to hour-long periods was distinguishable from background variability. Diel variability in pH, ara and cal showed a clear pattern that appeared to correlate with both salinity and temperature. Drift due to photodegradation of the fluorophore was minimised by reducing exposure to ambient light. Ca 15 and Ar fluctuated approximately on a daily cycle. The net result of changes in pH, salinity and temperature combined to influence seawater carbonate chemistry. The fluorescence-based pH monitoring technique is simple, provides good resolution and is unaffected by moving parts or leaching of solutions over time. The use of optics is pressure insensitive, making this approach to ocean acidification monitoring well suited to deepwater applications.
Here we present the results of a multiple organizational level analysis conceived to identify acc... more Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between...
The quantum yield of photosystem II (φ II , also termed ΔF /F m ' or F v /F m in light-or darkacc... more The quantum yield of photosystem II (φ II , also termed ΔF /F m ' or F v /F m in light-or darkacclimated plants, respectively) of the tropical seagrass Halophila stipulacea was measured in situ using modulated fluorescence techniques over diel periods at a range of depths. Photosynthetic electron transport rates (ETRs), as derived from φ II values at specific ambient photosynthetically available radiation (PAR) irradiances, increased in direct proportion to increasing irradiance in the morning and, at shallow sites (7 to 10 m), reached saturating rates and then declined in the afternoon with lower PAR-specific ETRs. On the other hand, plants at 32 to 33 m showed no saturation even at midday, and the percentage reduction in PAR-specific afternoon ETRs was less than that of the shallower plants. The use of an automated shutter in the measuring device enabled non-photochemical quenching due to down-regulation and basal intrinsic non-radiative decay to be distinguished. While midday values of down-regulation were lower in deeper water, basal intrinsic non-radioactive decay remained fairly constant at 30 to 40% at all depths, with more variation in shallow waters. The maximal φ II (i.e. F v /F m ) reached similar values at midnight regardless of depth. H. stipulacea acclimates to the widely varying irradiances across this depth gradient by regularly modulating down-regulationbased non-photochemical quenching processes, while dissipating a large proportion of light energy through intrinsic decay regardless of depth.
Direct comparisons between photosynthetic O 2 evolution rate and electron transport rate (ETR) we... more Direct comparisons between photosynthetic O 2 evolution rate and electron transport rate (ETR) were made in situ over 24 h using the benthic macroalga Ulva lactuca (Chlorophyta), growing and measured at a depth of 1.8 m, where the midday irradiance rose to 400-600 µmol photons m −2 s −1 . O 2 exchange was measured with a 5-chamber data-logging apparatus and ETR with a submersible pulse amplitude modulated (PAM) fluorometer (Diving-PAM). Steady-state quantum yield ((F m −F t )/F m ) decreased from 0.7 during the morning to 0.45 at midday, followed by some recovery in the late afternoon. At low to medium irradiances (0-300 µmol photons m −2 s −1 ), there was a significant correlation between O 2 evolution and ETR, but at higher irradiances, ETR continued to increase steadily, while O 2 evolution tended towards an asymptote. However at high irradiance levels (600-1200 µmol photons m −2 s −1 ) ETR was significantly lowered. Two methods of measuring ETR, based on either diel ambient light levels and fluorescence yields or rapid light curves, gave similar results at low to moderate irradiance levels. Nutrient enrichment (increases in [NO 3 − ], [NH 4 + ] and [HPO 4 2− ] of 5-to 15-fold over ambient concentrations) resulted in an increase, within hours, in photosynthetic rates measured by both ETR and O 2 evolution techniques. At low irradiances, approximately 6.5 to 8.2 electrons passed through PS II during the evolution of one molecule of O 2 , i.e., up to twice the theoretical minimum number of four. However, in nutrient-enriched treatments this ratio dropped to 5.1. The results indicate that PAM fluorescence can be used as a good indication of the photosynthetic rate only at low to medium irradiances.
... The primary column was 15m0.32mmi.d. x0.25mm DBI701 (J and W Scientific) with hydrogen at 41 ... more ... The primary column was 15m0.32mmi.d. x0.25mm DBI701 (J and W Scientific) with hydrogen at 41 369 N m 2 as the carrier gas. ... et al., 1983 Subramanian et al., 1983 Subramanian et al., 1983 De Kock and Boshoff, 1987 De Kock and Boshoff, 1987 E1 Nabawi et al., 1987 El ...
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