A5049621044- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Geochemistry and Elemental Analysis
- Heavy metals in environment
- Mercury impact and mitigation studies
- Microbial Community Ecology and Physiology
- Environmental Toxicology and Ecotoxicology
- Electrochemical Analysis and Applications
- Geochemistry and Geologic Mapping
- Ocean Acidification Effects and Responses
- Oceanographic and Atmospheric Processes
- Protist diversity and phylogeny
- Maritime Transport Emissions and Efficiency
- Wastewater Treatment and Nitrogen Removal
- Marine Toxins and Detection Methods
- Cruise Tourism Development and Management
- Chromium effects and bioremediation
- Hydrocarbon exploration and reservoir analysis
- Iron oxide chemistry and applications
- Maritime Navigation and Safety
- Environmental DNA in Biodiversity Studies
- Methane Hydrates and Related Phenomena
- Aquatic Ecosystems and Phytoplankton Dynamics
- Ammonia Synthesis and Nitrogen Reduction
- Analytical chemistry methods development
University of Liverpool
2014-2024
Institut Universitaire Européen de la Mer
2018-2022
Laboratoire des Sciences de l'Environnement Marin
2017-2022
Université de Bretagne Occidentale
2019-2020
Centre National de la Recherche Scientifique
2019-2020
Institut de Recherche pour le Développement
2019-2020
Ifremer
2019-2020
Copper-binding humic substances (Cu–HS) in seawater were determined using a novel method based on cathodic stripping voltammetry (CSV). Cu–HS adsorb the mercury (Hg) surface and are quantified basis of reduction current for complexed Cu. Humic acid reference material (Suwannee River acid, HA) was used to calibrate voltammetric response HS. The determine concentration estuarine coastal seawater, giving very good agreement with HS by UV spectrophotometry. Optimised conditions include Cu 20–50...
We determined the concentration of iron- and copper-binding humic substances (Fe-HS Cu-HS) in estuarine waters along with concentrations copper-complexing ligands (LFe LCu). Suwannee River acid (SRHA) was used as a standard. The complex stability Fe salicylaldoxime (SA) calibrated for salinities between 4 35 fitted to linear equations enable speciation waters: K′Fe′SA = − 2.98 × 104 Sal + 4.60 106 log B′Fe′SA2 1.41 12.85. Cu-HS from Mersey estuary Liverpool bay less than overall ligand...
Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, calculated rate entrainment entire volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable that deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within have long been known potential impact global-scale cycles. More recently, new results from GEOTRACES revealed rich...
Copper distribution and speciation were determined at stations P4 P26 along Line P as part of a GEOTRACES Process Study in the Northeast Pacific, depths between 10 1400 m. Two ligand classes (L1 L2) detected both stations: stronger L1 pool with log K'Cu2+L1 15.0–16.5 weaker L2 K'Cu2+L2 11.6–13.6. The class bound on average 94% dCu, ratio dCu constant close to unity (1.15 = [L1]:[dCu]). concentrations total ligands exceeded those all depths, buffering Cu2+ ([Cu2+]) femtomolar levels (i.e. pCu...
Abstract Primary production by phytoplankton represents a major pathway whereby atmospheric CO 2 is sequestered in the ocean, but this requires iron, which scarce supply. As over 99% of iron complexed to organic ligands, increase solubility and microbial availability, understanding processes governing ligand dynamics fundamental importance. Ligands within humic-like substances have long been considered important for complexation, their role has never explained an oceanographically consistent...
Abstract Organic Cu-binding ligands have a fundamental influence on Cu distributions in the global ocean and they complex >99% of dissolved seawater. however, represent large diversity compounds with distinct sources, sinks chemical properties. This heterogeneity makes organic ligand pool difficult to study at scale. In this review, we provide an overview that compose marine Cu-ligand pool, their dominant sources sinks. We also summarize most common analytical methods measure water column...
The GEOTRACES program has greatly expanded measurements of dissolved trace metal concentrations across ocean basins, but to understand the behavior and cycling metals their impacts on primary productivity, we must chemical forms in which they are present environment. Organic ligands play a central role speciation marine environment, controlling reactivity bioavailability. Here, an overview contributions made understanding through advancing our knowledge distribution, sources, sinks...
Iron (Fe) is an essential micronutrient for phytoplankton growth, but its scarcity in seawater limits primary productivity across much of the ocean. Most dissolved Fe (DFe) complexed with Fe-binding organic ligands, a poorly constrained fraction matter (DOM), which increase residence time and impact bioavailability. Here, we present conditional concentration (L ) binding-strength (log <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"...
The concentrations of dissolved copper (Cud), copper-binding ligands, thiourea-type thiols and humic substances (HSCu) were measured in estuarine waters adjacent to Sapelo Island, Georgia, USA, on a monthly basis from April December 2014. Here we present the seasonal cycle speciation within estuary compare it development an annually occurring bloom Ammonia Oxidising Archaea (AOA), which require for many enzymes. Two types complexing ligands (L1 L2) found dominate with mean complex...
Abstract Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing ligand pool composition are poorly constrained, limiting our understanding controls on dissolved iron distributions. To address this, release and iron‐binding ligands during microbial remineralization sinking particles was investigated by deploying situ particle interceptor/incubator devices at subsurface sites Mediterranean Sea...
In the Western Tropical South Pacific (WTSP) Ocean, a hotspot of dinitrogen fixation has been identified. The survival diazotrophs depends, among others, on availability dissolved iron (DFe) largely originating, as recently revealed, from shallow hydrothermal sources located along Tonga-Kermadec arc that fertilize Lau Basin with this element. On opposite, these fluids, released directly close to photic layer, can introduce numerous trace metals at concentrations be toxic surface communities....
The high N 2 fixation rate observed in the Lau Basin of western tropical South Pacific Ocean (WTSP) is fueled by iron (Fe) released from shallow hydrothermal systems. Understanding Fe bioavailability crucial but controls on stability and inputs are still poorly understood. Here, we provide new data spatial vertical distribution soluble ubiquitous humic-like ligands (L FeHS ) their associated dissolved (DFe) WTSP, including samples near vents. Our show that L heterogenous with binding sites...
While hydrothermal vents are a recognized source of trace elements to the ocean inventory, contribution slow-spreading ridges remains poorly resolved. To address this, high-resolution dissolved (<0.45µm) iron (dFe) and manganese (dMn) samples were collected during GEOTRACES HERMINE GApr07 process study at Mid Atlantic Ridge. Samples nine stations, from TAG vent site 75 km south-southwest following neutrally buoyant plume. Concentrations dMn dFe ranged 71 ± 6 51 2 nmol kg-1 right above 0.43...
Abstract Variation in the microbial cycling of nutrients and carbon ocean is an emergent property complex planktonic communities. While recent findings have considerably expanded our understanding diversity distribution nitrogen (N 2 ) fixing marine diazotrophs, knowledge gaps remain regarding ecological interactions between diazotrophs other community members. Using quantitative 16S 18S V4 rDNA amplicon sequencing, we surveyed eukaryotic prokaryotic communities from samples collected August...
Iron (Fe) and manganese (Mn) are crucial micronutrients that limit oceanic primary productivity in the Southern Ocean. It has been recently suggested hydrothermal activity may be an important source of dissolved iron, yet, this contribution is still not fully understood only one active site reported on Southwest Indian Ridge (SWIR), south 40°S. Using a multi-proxy approach, study demonstrates occurrence venting SWIR near vicinity location 44°51.690 S, 36°10.460 E, which likely to low or...
Reduced sulfur species (RSS) are involved in essential biological and chemical processes, including metal complexation, yet little is known about their occurrence behaviour marine systems. Here, we present a quantitative qualitative data set of species-specific RSS open ocean samples collected during the GEOTRACES Tonga GPpr14 cruise. The cruise traversed differing biogeochemical provinces, from mesotrophic Melanesian waters North Fiji Basin, through hydrothermally active Lau eastward to...