D. Frew results 22
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Motivation Arbuscular mycorrhizal (AM) fungi are central to plant nutrient acquisition, soil carbon dynamics, and ecosystem resilience. Yet, their biogeography remains incompletely characterised, particularly across underrepresented regions. Australia, with its characteristic ecological conditions, continental scale, and long‐standing evolutionary trajectories, has been notably undersampled. This gap hinders our ability to mak...
Biophysical predictors of spatial variation in abundance and population dynamics of an invasive decapodNARA Subscribed
Population dynamics of invasive species and their impacts on native communities vary substantially geographically and in different environmental contexts. Therefore, effective management of invasive species requires understanding how habitat characteristics, anthropogenic effects, or other perturbations can influence their abundance and impacts on native communities at multiple spatial and temporal scales. This is particularly...
Prolonging survival in good health is a fundamental societal goal. However, the leading determinants of disability-free survival in healthy older people have not been well established. Data from ASPREE, a bi-national placebo-controlled trial of aspirin with 4.7 years median follow-up, was analysed. At enrolment, participants were healthy and without prior cardiovascular events, dementia or persistent physical disability. Disab...
δ 56 Fe in seabird guano reveals extensive recycling of iron in the Southern Ocean ecosystemNARA Subscribed
Availability of iron limits productivity in the Southern Ocean where vast regions of high‐nitrogen low‐chlorophyll conditions are punctuated by hotspots of production surrounding the subAntarctic islands. Here, we compare patterns in accumulation of iron, as indicated by [Fe] and Fe : C (from Wing et al. ), with proxies for uptake of iron within food webs, as indicated by Fe : Al and δ 56 Fe within the subAntarctic Auckland Is...
In laboratory experiments we examined the interplay of light and iron availability on the intracellular iron concentrations, specific growth rates, and photosynthetic physiology of Southern (S.) Ocean diatoms ( Eucampia antarctica and Proboscia inermis ) and the haptophyte Phaeocystis antarctica . Intracellular iron concentrations and iron : carbon (Fe : C) molar ratios increased with decreasing irradiance in temperate coastal...
Sea ice microbial production supports Ross Sea benthic communities: influence of a small but stable subsidyNARA Subscribed
Diversity in guilds of primary producers enhances temporal stability in provision of organic matter to consumers. In the Antarctic ecosystem, where temporal variability in phytoplankton production is high, sea ice contains a diatom and microbial community (SIMCO) that represents a pool of organic matter that is seasonally more consistent, although of relatively small magnitude. The fate of organic material produced by SIMCO in...
We report results of laboratory studies examining the effect of low levels of iron (Fe) availability on the intracellular Fe concentrations and specific growth rates in Southern Ocean diatoms ( Fragilariopsis kerguelensis , Eucampia antarctica , Proboscia inermis , and Thalassiosira antarctica ) and Phaeocystis antarctica . All species grew on Fe complexed to the siderophore desferrioxamine B (DFB). Concentrations of DFB up to...
On Conch Reef, Florida Keys, USA, we examine relationships between temperature variability measured with a unique, high‐resolution sensor network, and the abundance of benthic reef organisms and carbon, nitrogen and oxygen stable isotopic composition of two abundant macroalgal species. Visualization of spatial temperature anomalies mapped onto measured reef bathymetry reveals episodic thermal patchiness and persistent thermal...
We examined nitrogen (N) uptake in seven grassland streams lying in catchments along a gradient (0–84%) of agricultural land use in New Zealand using a stable isotope ( 15 N) addition of NH 4 + to quantify whole‐stream uptake rates and uptake by specific compartments within the streams. Whole‐stream uptake of NH 4 + ranged from 1.2 mmol N m −2 min −1 to 7.9 mmol N m −2 min −1 and showed no evidence of strong saturation of upta...
Patterns in the δ13C and δ15N signature of Ulva pertusa: Interaction between physical gradients and nutrient source poolsNARA Subscribed
Field surveys and laboratory experiments were used to investigate the influence of the physical environment on variability in δ 13 C and δ 15 N signatures of Ulva pertusa , an abundant macroalgae inhabiting the low salinity layer (LSL) of Doubtful Sound, a New Zealand fjord. Field surveys revealed significant spatial variability in δ 13 C (‐18% to ‐12%) and δ 15 N (0% to 6%). δ 13 C was enriched at high irradiance sites and de...
Macroinvertebrate diet in intertidal seagrass and sandflat communities: A study using C, N, and S stable isotopesNARA Subscribed
Most seagrass community food‐web studies using stable isotopes have been carried out in subtidal habitats during one sampling event. We used C, N, and S stable isotopes to characterise the diet of the dominant macroinvertebrates found in intertidal Zostera capricorni and sandflat communities of southern New Zealand in late summer and winter. The range of ä 13 C and ä 34 S values for Z. capricorni was wide (>5‰), which highligh...
SMART-1 after lunar capture: First results and perspectivesNARA Subscribed
Iron uptake and physiological response of phytoplankton during a mesoscale Southern Ocean iron enrichmentNARA Subscribed
Iron supply is thought to regulate primary production in high nitrate, low chlorophyll (HNLC) regions of the sea in both the past and the present. A critical aspect of this relationship is acquisition of iron (Fe) by phytoplankton, which occurs through a complex series of extracellular reactions that are influenced by Fe chemistry and speciation. During the first in situ mesoscale Fe‐enrichment experiment in the Southern Ocean...
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