A5012816010- Magnetism in coordination complexes
- X-ray Spectroscopy and Fluorescence Analysis
- Hydrocarbon exploration and reservoir analysis
- Iron oxide chemistry and applications
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Marine Biology and Ecology Research
- Geochemistry and Geologic Mapping
- Arctic and Antarctic ice dynamics
- Polar Research and Ecology
- Microbial Community Ecology and Physiology
- Marine and environmental studies
- Geochemistry and Elemental Analysis
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Heavy metals in environment
- Mercury impact and mitigation studies
- Paleontology and Stratigraphy of Fossils
- RNA modifications and cancer
- Bauxite Residue and Utilization
- X-ray Diffraction in Crystallography
- Geomagnetism and Paleomagnetism Studies
- Radioactivity and Radon Measurements
- Radioactive contamination and transfer
University of Southampton
2019-2025
National Oceanography Centre
2020-2025
University of Edinburgh
2007-2018
Rutgers, The State University of New Jersey
2017-2018
University of British Columbia
2008-2010
We investigated the effects of copper (Cu) and iron (Fe) availability on growth rates, cellular Cu content, steady‐state uptake rates eight species centric diatoms (coastal oceanic strains). Whereas Fe had a significant effect both costal diatoms, an interaction between was only observed for diatoms. Determination : carbon (C) quotas using radiotracers 67 14 C revealed that under Cu‐sufficient conditions elevated :C ratios relative to coastal strains, regardless availability. Two (one one...
Iron (Fe) is an essential micronutrient for phytoplankton, and scarce in many regions including the open Southern Ocean. The western Antarctic Peninsula (WAP), important source region of Fe to wider Ocean, also fastest warming Hemisphere. relative importance glacial versus marine sources currently poorly constrained, hindering projections how changing oceanic circulation, productivity, dynamics may affect balance this region. Dissolved total dissolvable concentrations were measured...
Nutrient supply, uptake and cycling underpin high primary productivity over the continental shelf of west Antarctic Peninsula (WAP). Here we use a suite biogeochemical isotopic data collected five years in northern Marguerite Bay to examine these macronutrient dynamics their controlling biological physical processes WAP coastal ocean. We show pronounced nutrient drawdown summer months by production which drives net seasonal nitrate 1.83 mol N m-2 yr-1, equivalent carbon 146 g C yr-1. High...
Palmer Deep (PD) is one of several regional hotspots biological productivity along the inner shelf West Antarctic Peninsula. The proximity to shelf-crossing deep troughs has led ‘canyon hypothesis’, which proposes that circumpolar water flowing shoreward canyons upwelled on shelf, carrying nutrients including iron (Fe) surface waters, maintaining phytoplankton blooms. We present here full-depth profiles dissolved and particulate Fe manganese (Mn) from eight stations around PD, sampled in...
Abstract. A high resolution time-series analysis of stable carbon isotopic signatures in particulate organic (δ13CPOC) and associated biogeochemical parameters sea ice surface waters provides an insight into the factors affecting δ13CPOC coastal western Antarctic Peninsula environment. The study covers two austral summer seasons Ryder Bay, northern Marguerite Bay between 2004 2006. shift diatom species composition during 2005/06 bloom to near-complete biomass dominance Proboscia inermis is...
Oceanographic changes adjacent to Antarctica have global climatic and ecological impacts. However, this is the most challenging place in world obtain marine data due its remoteness inhospitable nature, especially winter. Here, we present more than 2000 Conductivity-Temperature-Depth (CTD) profiles associated water sample collected with (almost uniquely) full year-round coverage from British Antarctic Survey Rothera Research Station at west Peninsula. Sampling conducted a small boat or sled,...
Abstract The benthic flux of nutrients underpins marine food webs, influences conditions for life in the oceans, and contributes to climatic feedback. Estimates these fluxes' contributions macro‐ micronutrient cycles are, however, highly variable, generating significant uncertainty biogeochemical models. Traditional methodologies have potentially limitations, geochemically framed studies, there is a notable omission from macrofaunal activity. 224 Ra/ 228 Th disequilibrium cutting‐edge...
Ocean mixing around Antarctica exerts key influences on glacier dynamics and ice shelf retreats, sea ice, marine productivity, thus affecting global level climate. The conventional paradigm is that this dominated by winds, tides, buoyancy forcing. Direct observations from the Antarctic Peninsula demonstrate calving triggers internal tsunamis, breaking of which drives vigorous mixing. Being widespread frequent, these tsunamis are at least comparable to much more important than in driving...
We investigated copper (Cu) acquisition mechanisms and uptake kinetics of the marine diatoms Thalassiosira oceanica Hasle, an oceanic strain, pseudonana Hasle et Heimdal, a coastal grown under replete limiting iron (Fe) Cu availabilities. The Cu‐uptake these two followed classical Michaelis–Menten kinetics. Biphasic as function concentration were observed, suggesting presence both high‐ low‐affinity Cu‐transport systems. half‐saturation constants ( K m ) maximum rates V max high‐affinity...
Abstract Anthropogenic activities have resulted in enhanced lead (Pb) emissions to the environment over past century, mainly through combustion of leaded gasoline. Here we present first combined dissolved (DPb), labile (LpPb), and particulate (PPb) Pb data set from Northeast Atlantic (Celtic Sea) since phasing out gasoline Europe. Concentrations DPb surface waters decreased by fourfold last four decades. We demonstrate that anthropogenic is transported Mediterranean Sea long distances...
Abstract The speciation of iron (Fe) reaching the ocean, for instance in wind‐blown dust and coastal sediments, impacts its bioavailability to phytoplankton impact on atmospheric carbon dioxide (CO 2 ) climate. For Southern Ocean, primary Fe(II) silicates that are physically weathered from bedrock highly bioavailable compared more chemically weathered, Fe(III)‐rich species, suggesting weathering source regions Fe supply. However, this phenomenon has not been studied other important...
Abstract In the western Antarctic Peninsula region, micronutrient injection facilitates strong plankton blooms that support productive food webs, unlike large areas of low-productivity Southern Ocean. We use naturally occurring radioisotopes radium to constrain rates chemical fluxes into Ryder Bay (a small coastal embayment in northern Marguerite Bay), and hence evaluate possible sources sediment-derived micronutrients estimate sediment-ocean mixing rates. present first coupled, short-lived...
Abstract Our study followed the seasonal cycling of soluble (SFe), colloidal (CFe), dissolved (DFe), total dissolvable (TDFe), labile particulate (LPFe), and (TPFe) iron in Celtic Sea (NE Atlantic Ocean). Preferential uptake SFe occurred during spring bloom, preceding removal CFe. Uptake export Fe coupled with a reduction vertical exchange, led to deplete surface waters (<0.2 nM DFe; 0.11 LPFe, 0.45 TDFe, 1.84 TPFe) summer stratification. Below thermocline, DFe concentrations increased...
Abstract Glaciers and ice sheets are experiencing rapid warming under current climatic change there is increasing evidence that glacial meltwaters provide key dissolved dissolvable amorphous nutrients to downstream ecosystems. However, large debate exists around the fate of these within complex heterogenous fjord environments, where biogeochemical cycling still often poorly understood. We combine silicon (Si) concentration data with isotopic compositions better understand export in two...
We present a new method to determine 226 Ra in aqueous environmental samples, based on the rate of ingrowth 222 Rn from Ra, using radium delayed coincidence counter (RaDeCC). use same instrument setup that is used for determination 223 and 224 Ra. In contrast methods published earlier, approach does not require modification counting equipment, separately or waiting radioactive equilibrium. show calibration works as low 10 dpm (0.166 Bq) per sample, up more than 1000 (16.7 Bq). Although...
At the West Antarctic Peninsula (WAP), continued atmospheric and oceanic warming is causing significant physical biogeochemical changes to glaciers marine environment. We compare sediment sources drivers of macronutrient distributions at two bays along WAP during austral summer 2020, using radioactive radium stable oxygen isotopes trace sedimentary influences quantify different freshwater inputs. In Ryder Bay, where Sheldon Glacier marine-terminating, activities sediment-water interface...