A5017572605- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Ocean Acidification Effects and Responses
- Oceanographic and Atmospheric Processes
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Microbial Community Ecology and Physiology
- Marine Bivalve and Aquaculture Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Atmospheric Ozone and Climate
- Odor and Emission Control Technologies
- Air Quality Monitoring and Forecasting
- Geology and Paleoclimatology Research
- Soil and Water Nutrient Dynamics
- Atmospheric aerosols and clouds
- Hydrocarbon exploration and reservoir analysis
- Marine and fisheries research
- Groundwater and Isotope Geochemistry
- Climate variability and models
- Geochemistry and Elemental Analysis
- Polar Research and Ecology
- Oil Spill Detection and Mitigation
- Aeolian processes and effects
University of Otago
2016-2025
National Institute of Water and Atmospheric Research
2016-2025
Crown Research Institutes
2024
University of Tasmania
2023
Qatar University
2015
Plymouth Marine Laboratory
2000-2011
United States Geological Survey
2008
Old Dominion University
2008
Newcastle University
2008
University of East Anglia
2007
Measurements of air‐sea gas exchange rates are reported from two deliberate tracer experiments in the southern North Sea during February 1992 and 1993. A conservative tracer, spores bacterium Bacillus globigii var. Niger , was used for first time an situ experiment. This nonvolatile is to correct dispersive dilution volatile tracers allows three estimations transfer velocity same period. The estimation power dependence on molecular diffusivity marine environment reported. impact bubbles...
Comparison of eight iron experiments shows that maximum Chl a , the DIC removal, and overall DIC/Fe efficiency all scale inversely with depth wind mixed layer (WML) defining light environment. Moreover, lateral patch dilution, sea surface irradiance, temperature, grazing play additional roles. The Southern Ocean were most influenced by very deep WMLs. In contrast, conditions favorable during SEEDS SERIES as well IronEx‐2. two extreme experiments, EisenEx SEEDS, can be linked via bottle...
A patch of sulfur hexafluoride was released in May 1992 the eastern North Atlantic on an isopycnal surface near 300 m depth and surveyed over a period 30 months as it dispersed across along surfaces. The diapycnal eddy diffusivity K estimated for first 6 0.12±0.02 cm 2 /s, while subsequent 24 0.17±0.02 /s. vertical tracer distribution remained very close to Gaussian full months, root mean square (rms) dispersion grew from 5 50 m. Lateral measured several scales. growth rms width streaks less...
The SOLAS Air‐Sea Gas Exchange (SAGE) Experiment was conducted in the western Pacific sector of Southern Ocean. During SAGE, gas transfer velocities were determined using 3 He/SF 6 dual tracer technique, and results obtained at higher wind speeds (16.0 m s −1 ) than previous open ocean experiments. clearly reveal a quadratic relationship between speed velocity rather recently proposed cubic relationship. A new parameterization is proposed, which consistent with from coastal lower speeds....
Phosphate addition to surface waters of the ultraoligotrophic, phosphorus-starved eastern Mediterranean in a Lagrangian experiment caused unexpected ecosystem responses. The system exhibited decline chlorophyll and an increase bacterial production copepod egg abundance. Although nitrogen phosphorus colimitation hindered phytoplankton growth, phosphorous may have been transferred through microbial food web copepods via two, not mutually exclusive, pathways: (i) bypass compartment by uptake...
Carbon sequestration is defined as the secure storage of carbon‐containing molecules for >100 years, and in context carbon dioxide removal climate mitigation, origin this CO 2 from atmosphere. On land, trees globally sequester substantial amounts woody biomass, an analogous role seaweeds ocean has been suggested. The purposeful expansion natural seaweed beds aquaculture systems, including into open (ocean afforestation), proposed a method increasing use trading offset schemes. However, to...
An improved knowledge of iron biogeochemistry is needed to better understand key controls on the functioning high‐nitrate low‐chlorophyll (HNLC) oceanic regions. Iron budgets for HNLC waters have been constructed using data from disparate sources ranging laboratory algal cultures ocean physics. In summer 2003 we conducted FeCycle, a 10‐day mesoscale tracer release in SE New Zealand, and measured concurrently all (with exception aerosol deposition) to, sinks from, rates recycling within,...
Abstract In the vast Low Nutrient Low‐Chlorophyll (LNLC) Ocean, vertical nutrient supply from subsurface to sunlit surface waters is low, and atmospheric contribution of nutrients may be one order magnitude greater over short timescales. The turnover time Fe N (<1 month for nitrate) further supports deposition being an important source in LNLC regions. Yet, extent which inputs are impacting biological activity modifying carbon balance oligotrophic environments has not been constrained....
Abstract. The aerosol-driven radiative effects on marine low-level cloud represent a large uncertainty in climate simulations, particular over the Southern Ocean, which is also an important region for sea spray aerosol production. Observations of organic enrichment and resulting impact water uptake remote Hemisphere are scarce, therefore under-represented existing parameterisations. Surface Ocean Aerosol Production (SOAP) voyage was 23 d sampled three phytoplankton blooms highly productive...
1. Abstract Nitrous oxide (N2O) is an important atmospheric trace gas involved in tropospheric warming and stratospheric ozone depletion. Estimates of the global ocean contribution to N2O emissions average 21 % (range: 10 53 %). Ongoing environmental changes such as warming, deoxygenation acidification are affecting oceanic cycling atmosphere. International activities over last decades aimed at improving estimates emissions, including (i) MarinE MethanE NiTrous Oxide database (MEMENTO) for...
During the 13 day Southern Ocean Iron RE‐lease Experiment (SOIREE), dissolved iron concentrations decreased rapidly following each of three iron‐enrichments, but remained high (>1 nM, up to 80% as Fe II ) after fourth and final enrichment on 8. The former trend was mainly due dilution (spreading iron‐fertilized waters) particle scavenging. latter may only be explained by a joint production‐maintenance mechanism; photoreduction is candidate process able produce sufficiently , such levels...
We initiated and mapped a diatom bloom in the northeast subarctic Pacific by concurrently adding dissolved iron tracer sulfur hexafluoride to mesoscale patch of high-nitrate, low-chlorophyll waters. The was dominated pennate diatoms monitored for 25 d, which sufficiently long observe evolution termination most decline phase. Fast repetition–rate fluorometry indicated that were iron-replete until day 12, followed 4–5-d transition limitation. This period characterized relatively high rates...