Delphine Lannuzel

Delphine Lannuzel
University of Tasmania · Institute for Marine and Antarctic Studies (IMAS)

PhD in marine chemistry

About

90
Publications
19,616
Reads
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4,080
Citations
Citations since 2016
36 Research Items
2613 Citations
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20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400

Publications

Publications (90)
Article
Full-text available
The discovery that melting sea ice can fertilize iron (Fe)-depleted polar waters has recently fostered trace metal research efforts in sea ice. The aim of this review is to summarize and synthesize the current understanding of Fe biogeochemistry in sea ice. To do so, we compiled available data on particulate, dissolved, and total dissolvable Fe (PF...
Article
Polynyas represent regions of enhanced primary production because of the low, or absent, sea-ice cover coupled with the proximity of nutrient sources. However, studies throughout the Southern Ocean suggest elevated primary production does not necessarily result in increased carbon export. Three coastal polynyas in East Antarctica and an off-shelf r...
Article
Full-text available
The availability of iron (Fe) to marine microbial communities is enhanced through complexation by ligands. In Fe limited environments, measuring the distribution and identifying the likely sources of ligands is therefore central to understanding the drivers of marine productivity. Antarctic coastal marine environments support highly productive ecos...
Technical Report
Full-text available
The Southern Ocean plays a central role in the Earth System by connecting the Earth’s ocean basins, and it is a crucial link between the deep ocean, surface ocean and atmosphere. Hence, the ongoing changes in the Southern Ocean impact global climate, rates of sea level rise, biogeochemical cycles and ecological systems. Yet, understanding of the ca...
Preprint
Full-text available
Antarctic sea ice is a seasonal source of iron (Fe) to the Southern Ocean (SO), where surface waters Fe levels are otherwise generally low. The effectiveness of Fe released from melting sea ice does not only depends on the magnitude of the supply, but also on the biological Fe demand. Here, we hypothesize that Fe uptake rates by sea-ice algae and u...
Article
Full-text available
Iron (Fe) has been shown to limit growth of marine phytoplankton in the Southern Ocean, regulating phytoplankton productivity and species composition, yet does not seem to limit primary productivity in Antarctic sea ice. Little is known, however, about the potential impact of other metals in controlling sea-ice algae growth. Here, we report on the...
Article
Full-text available
Despite widespread iron (Fe) limitation in the Southern Ocean, intense phytoplankton blooms are observed around productive coastal regions such as the Mertz Polynya (off George V Land and Adelie Land, East Antarctica; 140–155°E). Sources of Fe across coastal East Antarctica vary, with limited data available for late summer months. We investigated t...
Article
It is widely accepted that iron (Fe)-binding organic ligands play a crucial role in Fe distribution in the marine environment and thus in Fe biogeochemistry. Although Competitive Ligand Equilibration – Adsorptive Cathodic Stripping Voltammetry (CLE-AdCSV) is a well-established technique to investigate Fe chemical speciation in marine samples, sever...
Article
Full-text available
A rigorous synthesis of the sea-ice ecosystem and linked ecosystem services highlights that the sea-ice ecosystem supports all 4 ecosystem service categories, that sea-ice ecosystems meet the criteria for ecologically or biologically significant marine areas, that global emissions driving climate change are directly linked to the demise of sea-ice...
Article
Full-text available
A paradox is commonly observed in productive sea ice in which an accumulation in the macro-nutrients nitrate and phosphate coincides with an accumulation of autotrophic biomass. This paradox requires a new conceptual understanding of the biogeochemical processes operating in sea ice. In this study, we investigate this paradox using three time serie...
Article
Full-text available
Antarctic sea ice can incorporate high levels of iron (Fe) during its formation and has been suggested as an important source of this essential micronutrient to Southern Ocean surface waters during the melt season. Over the last decade, a limited number of studies have quantified the Fe pool in Antarctic sea ice, with a focus on late winter and spr...
Article
Full-text available
Polynyas are subject to variability in winds and ocean circulation and are important sites of ecological productivity. In February 2010, the B09B iceberg collided with the Mertz Glacier Tongue (MGT), calving a 78 × 40‐km giant iceberg which modified the icescape and primary productivity of the Mertz polynya. In this study, we use satellite ocean co...
Article
Full-text available
The Arctic sea-ice-scape is rapidly transforming. Increasing light penetration will initiate earlier seasonal primary production. This earlier growing season may be accompanied by an increase in ice algae and phytoplankton biomass, augmenting the emission of dimethylsulfide and capture of carbon dioxide. Secondary production may also increase on th...
Article
We incubated Fe-limited seawater with sea-ice sections to evaluate which forms of iron (Fe) released from melting sea ice can favor phytoplankton growth. Biological availability (bioavailability) was approximated by fractionating Fe into soluble (<1000 kDa), colloidal (1000 kDa–0.2 μm), and labile particulate (>0.2 μm) sizes. Results show that phyt...
Article
Full-text available
Antarctic sea ice is an important temporal reservoir of iron which can boost primary production in the marginal ice zone during the seasonal melt. While studies have reported that Antarctic fast ice bears high concentrations of iron due to the proximity to coastal sources, less clear are the biogeochemical changes this iron pool undergoes during la...
Article
Full-text available
We use field observations from late spring and a one‐dimensional sea‐ice model to explore a high nutrient, high chlorophyll system in Antarctic land‐fast ice. Lack of variability in chlorophyll a concentration and organic carbon content over the 17‐day sampling period suggests a balance between macronutrient sources and biological uptake. Nitrate,...
Article
Full-text available
In the Southern Ocean, polynyas exhibit enhanced rates of primary productivity and represent large seasonal sinks for atmospheric CO2. Three contrasting east Antarctic polynyas were visited in late December-early January 2017: the Dalton, Mertz and Ninnis polynyas. In the Mertz and Ninnis polynyas, phytoplankton biomass (average of 322 and 354 mg C...
Article
A seawater preconcentration system (seaFAST) with offline sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS) detection was critically evaluated for ultra-low trace elemental analysis of Southern Ocean samples over a four-year period (2015-2018). The commercially available system employs two Nobias PA1 resin columns for buffer cle...
Article
Historical sea ice core chlorophyll-a (Chla) data are used to describe the seasonal, regional, and vertical distribution of ice algal biomass in Antarctic landfast sea ice. The analyses are based on the Antarctic Fast Ice Algae Chlorophyll-a data set, a compilation of currently available sea ice Chla data from landfast sea ice cores collected at ci...
Article
Adélie Land Bottom Water (ALBW), a variety of Antarctic Bottom Water formed off the Adélie Land coast of East Antarctica, ventilates the abyssal layers of the Australian sector of the Southern Ocean as well as the eastern Indian and Pacific Oceans. We present the first dissolved neodymium (Nd) isotope and concentration measurements for ALBW. The su...
Article
Abstract Since Antarctic sea ice covers an area larger than the Antarctic continent itself, the discovery that it can fertilize the Southern Ocean with iron (Fe) has fostered a new breadth of research in recent years. In order to test the hypothesis that Fe-binding organic ligands control the distribution of dissolved iron (DFe) in Antarctic pack i...
Article
Full-text available
This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to underst...
Article
Primary productivity in large areas of the Southern Ocean is limited by the availability of a key micronutrient—iron (Fe). Recently it has been suggested that marine animals could play an important role in recycling Fe through their diet and subsequent defecation, however there is no information on the relative bioavailability of faecal Fe for upta...
Article
Full-text available
Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and...
Article
Full-text available
Antarctic pack ice is inhabited by a diverse and active microbial community reliant on nutrients for growth. Seeking patterns and overlooked processes, we performed a large-scale compilation of macro-nutrient data (hereafter termed nutrients) in Antarctic pack ice (306 ice-cores collected from 19 research cruises). Dissolved inorganic nitrogen and...
Article
Full-text available
This study reports concentrations of iron (Fe) and organic matter in young Antarctic pack ice and during its initial growth stages in situ. Although the importance of sea ice as an Fe reservoir for oceanic waters of the Southern Ocean has been clearly established, the processes leading to the enrichment of Fe in sea ice have yet to be investigated...
Article
Full-text available
The Antarctic continental shelf supports a high level of marine primary productivity and is a globally important carbon dioxide (CO2) sink through the photosynthetic fixation of CO2 via the biological pump. Sustaining such high productivity requires a large supply of the essential micronutrient iron (Fe); however, the pathways for Fe delivery to th...
Article
Antarctic krill may play a significant role in the Southern Ocean iron cycle. However, understanding the control on iron budgets by Antarctic krill is hampered by the large range in the reported iron concentration of krill. The aim of this study was to investigate the causes of the large range of iron concentrations in krill reported in the literat...
Article
Full-text available
Numerical models can be a powerful tool helping to understand the role biogeochemical processes play in local and global systems and how this role may be altered in a changing climate. With respect to sea-ice biogeochemical models, our knowledge is severely limited by our poor confidence in numerical model parameterisations representing those proce...
Article
Dissolved Fe (dFe) concentrations were measured in the upper 1300 m of the water column in the vicinity of the Kerguelen Islands as part of the second KErguelen Ocean Plateau compared Study (KEOPS2). Concentrations ranged from 0.06 nmol L−1 in offshore, Southern Ocean waters to 3.82 nmol L−1 within Hillsborough Bay, on the north-eastern coast of th...
Article
Full-text available
Dissolved Fe (dFe) concentrations were measured in the upper 1300 m of the water column in the vicinity of the Kerguelen Islands as part of the second KErguelen Ocean Plateau compared Study (KEOPS2). Concentrations ranged from 0.06 nmol L −1 in offshore, Southern Ocean waters to 3.82 nmol L −1 within Hillsborough Bay, on the northeastern coast of t...
Article
Full-text available
The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical...
Article
Full-text available
Over the past two decades, with recognition that the ocean’s sea-ice cover is neither insensitive to climate change nor a barrier to light and matter, research in sea-ice biogeochemistry has accelerated significantly, bringing together a multi-disciplinary community from a variety of fields. This disciplinary diversity has contributed a wide range...
Article
Full-text available
Our study quantified the spatial and temporal distribution of Fe and ancillary biogeochemical parameters at six stations visited during an interdisciplinary Australian Antarctic marine science voyage (SIPEX-2) within the East Antarctic first-year pack ice zone during September-October 2012. Unlike previous studies in the area, the sea ice Chlorophy...
Article
Full-text available
The availability of micronutrients is a key factor that affects primary productivity in High Nutrient Low Chlorophyll (HNLC) regions of the Southern Ocean. Nutrient supply is governed by a range of physical, chemical and biological processes, and there are significant feedbacks within the ecosystem. It has been suggested that baleen whales form a c...
Article
Full-text available
We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines encased in the ice change from a CO2 large over-saturation, relative to the atmosphere, to a marked under-saturation while the underlying oceanic water...
Article
Full-text available
Trace metals are fundamental components of various biochemical reactions for phytoplankton. They serve as micronutrients and therefore play a key role in marine biogeochemical cycles. International programs such as GEOTRACES require fast, sensitive and reliable methods for the simultaneous analysis of multiple trace elements in seawater. This paper...
Article
Melting sea ice represents a large seasonal source of iron (Fe) for planktonic growth in the marginal ice zone, but no data currently show how accessible this Fe is for biological uptake. We investigated the size fractionation in East Antarctic fast ice of Fe, manganese (Mn) and aluminium (Al) in the soluble (< 100 kDa), colloidal (100 kDa-0.2 μm),...
Article
Observations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas exchanges at the sea ice interface through an often permeable sea ice cover; and (iii) tight physical, biological and chemical interactions betwee...
Article
Full-text available
Although algal growth in the iron-deficient Southern Ocean surface waters is generally low, there is considerable evidence that winter sea ice contains high amounts of iron and organic matter leading to ice-edge blooms during austral spring. We used field observations and ship-based microcosm experiments to study the effect of the seeding by sea ic...
Article
Full-text available
This study demonstrates that pygmy blue whale faeces stimulates the photosynthetic performance and growth of three marine phytoplankton species, Dunaliella tertiolecta, Chaetoceros pendulus and Phaeocystis antarctica. Photosynthetic and growth parameters were compared at four time-points over a 21 day experi-ment with 6 different treatments: a posi...
Article
Trace metal micronutrients regulate primary production in oceanic surface waters, particularly those characterised as 'high nutrient, low chlorophyll', such as the Subantarctic Zone (SAZ). Our goal was to evaluate the distribution and biogeochemistry of Cd, Co, Cu, Ni and Zn in the upper 1000 m of this zone to the south of Australia during the SAZ-...
Article
Full-text available
Sea ice core chlorophyll a data are used to describe the seasonal, regional and vertical distribution of algal biomass in Southern Ocean pack ice. The Antarctic Sea Ice Processes and Climate – Biology (ASPeCt – Bio) circumpolar dataset consists of 1300 ice cores collected during 32 cruises over a period of 25 years. The analyses show that integrate...
Article
Full-text available
In large parts of the Southern Ocean, primary production is limited due to shortage of iron (Fe). We measured vertical Fe profiles in the western Weddell Sea, Weddell-Scotia Confluence, and Antarctic Circumpolar Current (ACC), showing that Fe is derived from benthic Fe diffusion and sediment resuspension in areas characterized by high turbulence du...
Data
In large parts of the Southern Ocean, primary production is limited due to shortage of iron (Fe). We measured vertical Fe profiles in the western Weddell Sea, Weddell-Scotia Confluence, and Antarctic Circumpolar Current (ACC), showing that Fe is derived from benthic Fe diffusion and sediment resuspension in areas characterized by high turbulence du...
Article
This paper presents iron (Fe) profiles in the upper 1000 m from nine short-term (transect) stations and three long-term (process) stations occupied in the Australian sector of the Southern Ocean during the SAZ-Sense expedition in austral summer (January-February) 2007. Strong vertical and horizontal gradients in Fe concentrations were observed betw...
Article
A time series experiment was conducted in late austral spring (November-December 2009) in coastal fast ice, East Antarctica (66°13′07′′S, 110°39′02′′E). Iron (Fe) measurements were made in sea ice, snow, brines, and underlying seawater, together with meteorological, physical, and biogeochemical measurements to investigate the processes controlling...
Article
An investigation of coloured dissolved organic matter (CDOM) and its relationships to physical and biogeochemical parameters in Antarctic sea ice and oceanic water have indicated that ice melt may both alter the spectral characteristics of CDOM in Antarctic surface waters and serve as a likely source of fresh autochthonous CDOM and labile DOC. Samp...
Article
Iron is a fundamental nutrient limiting phytoplankton growth in vast regions of the Southern Ocean. Sea ice, which covers ∼80% of the Southern Ocean (south of 60°S) during maximum extent, can concentrate iron up to two orders of magnitude higher than in the underlying sea water. The fractionation of iron between the particulate and dissolved fracti...
Article
Samples were collected in East Antarctic sea ice in late winter/early austral spring 2007 to assess the distributions of Al, Cr, Mn, Cu, Zn, Mo. Cd and Ba. Total dissolved (<02 mu m) and particulate (>0.2 mu m) concentrations were measured by Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS) in snow, pack ice and fast ice. Partic...
Article
We present here the first mercury speciation study in the water column of the Southern Ocean, using a high-resolution south-to-north section (27 stations from 65.50°S to 44.00°S) with up to 15 depths (0–4440 m) between Antarctica and Tasmania (Australia) along the 140°E meridian. In addition, in order to explore the role of sea ice in Hg cycling, a...
Data
We present here the first mercury speciation study in the water column of the Southern Ocean, using a high-resolution south-to-north section (27 stations from 65.50°S to 44.00°S) with up to 15 depths (0-4440 m) between Antarctica and Tasmania (Australia) along the 140°E meridian. In addition, in order to explore the role of sea ice in Hg cycling, a...