A5055384192- Marine and coastal ecosystems
- Avian ecology and behavior
- Marine and fisheries research
- Marine Biology and Ecology Research
- Wildlife Ecology and Conservation
- Oceanographic and Atmospheric Processes
- Fish Ecology and Management Studies
- Marine animal studies overview
- Marine Bivalve and Aquaculture Studies
- Black Holes and Theoretical Physics
- Isotope Analysis in Ecology
- Underwater Acoustics Research
- Evolutionary Game Theory and Cooperation
- Aquatic Ecosystems and Phytoplankton Dynamics
- Ichthyology and Marine Biology
- Geology and Paleoclimatology Research
- Atmospheric and Environmental Gas Dynamics
- Animal Ecology and Behavior Studies
- Algebraic structures and combinatorial models
- Evolution and Genetic Dynamics
- Bird parasitology and diseases
- Animal Behavior and Reproduction
- Coastal wetland ecosystem dynamics
- Microbial Community Ecology and Physiology
- Mathematical and Theoretical Epidemiology and Ecology Models
University of Newcastle Australia
2025
Dragonfly Data Science (New Zealand)
2008-2020
National Institute of Water and Atmospheric Research
1998-2010
University of Cambridge
1989-1993
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,...
In the children's game of rock-scissors-paper, players each choose one three strategies. A rock beats a pair scissors, scissors beat sheet paper and rock, so strategies form competitive cycle. Although cycles in ability appear to be reasonably rare among terrestrial plants, they are common marine sessile organisms have been reported other contexts. Here we consider system with species loop show that this simple ecology exhibits two counter-intuitive phenomena. First, is least expected...
Abstract The identification of geographic areas where the densities animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map distribution species, and methods used usually biased towards adults, neglecting other life‐history stages even though they represent substantial proportion total population. Here we develop methodological framework for estimating population‐level density...
Dispersion of the tracer sulphur hexafluoride (SF 6 ) during Southern Ocean Iron Enrichment Experiment (SOIREE) provided an estimate vertical exchange at base surface mixed layer (60 m) 61°S 140°E. Budget analysis confirmed that SF patch was well constrained by mapping, with decline in total showing good agreement predicted from wind speed parameterizations. Two approaches were used to calculate mean effective diffusivity Kz diapycnal transfer , complementary error function and second‐moment...
An internal tide on the NE shelf of New Zealand was observed with a combination moored temperature loggers and current meters vertical profiling microstructure probe. Internal energy flux across edge calculated to be ∼400 W m −1 , considerable variability driven by passage storm through region. Energy associated significantly greater than barotropic or inertial shear. Dissipation from loss between two moorings estimated 15±10 mW −2 . The eddy diffusivity (4 ± 3) × 10 −4 2 s observations...
Global variations of stirring in the surface ocean are quantified using finite‐time Lyapunov exponents (FTLEs) calculated from currents derived satellite altimetry. It is shown that highly non‐uniform, and probability distribution functions (PDFs) FTLEs broad, asymmetric, have long high‐stretch tails. The characteristics PDFs vary with mesoscale activity integration time: There larger values broader regions high strain rates eddy kinetic energy (EKE), e.g., western boundary Antarctic...
The horizontal stirring properties of the flow in a region East Australian Current are calculated. A surface velocity field derived from remotely sensed data, using maximum cross correlation method, is integrated to derive distribution finite-time Lyapunov exponents. For studied (between latitudes 36 degrees S and 41 longitudes 150 E 156 E) mean exponent during 1997 estimated be lambda( infinity )=4x10(-7) s(-1). This close agreement with few other measurements rates ocean which available....
Abstract Stirring in the Tasman Sea is examined using surface geostrophic currents derived from satellite altimeter measurements. Calculations of distribution finite-time Lyapunov exponents (FTLEs) indicate that stirring this region not uniform and stretching rates over 15 days vary less than 0.02 day−1 to 0.3 day−1. These variations occur at both small (∼10 km) large (∼1000 scales cases are linked dynamical features flow. The small-scale related characteristics coherent vortex structures,...
The effects of physical processes on the distribution, speciation, and sources/sinks for Fe in a high‐nutrient low‐chlorophyll (HNLC) region were assessed during FeCycle, mesoscale SF 6 tracer release February 2003 (austral summer) to SE New Zealand. Physical mixing prevalent FeCycle with rapid patch growth (strain rate γ = 0.17–0.20 d −1 ) from circular shape (50 km 2 into long filament ∼400 by day 10. Slippage between layers saw patch‐head overlying noninfused waters while tail was capped...
The predominantly low-chlorophyll conditions of the Southern Ocean are punctuated by regions elevated phytoplankton biomass, including a bloom in Antarctic Circumpolar Current (ACC) that extends for 1000 km downstream Kerguelen-Heard islands. Summer-time studies have demonstrated iron from islands and intervening shallow plateau (300-600 m) fuels localized production. Whether this supply, or alternatively brought to surface enhanced mixing ACC eddies, drives more extensive has not been...