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Spectrometers

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  • The current data set contains spectral atmospheric measurements from: - Multi-Angle Differential Optical Absorption Spectrometer (MAX-DOAS) - built in-house at NIWA Lauder by Dr Karin Kreher, Mr Paul Johnston and Mr Alan Thomas. Instrument description and setup details: MAX-DOAS Instrument Description: The MAX-DOAS instrument consists of a Czerny-Turner type ISA HR320 flat-field spectrograph with a focal length of 320 mm and an aperture ratio of F/4. The array detector is a Hamamatsu C7042 detector head with S7032-1007 sensor chip. The chip is back-thinned, allowing light to enter from the rear of the silicon substrate, which substantially increases the quantum efficiency over the whole spectral range, especially in the UV region (less than 400 nm). The sensitivity in the UV is important in order to obtain a good signal-to-noise ratio for BrO measurements. The detector signal is then passed to the computer via a 16-bit analogue to digital converter card. The detector is cooled to -20oC using a Peltier cooler to minimise the dark current noise caused by thermally excited electrons. The entrance optics consisted of an angled telescope mirror that reflects the measured light down through a focusing lens onto the entrance of a quartz fibre optic bundle leading into the spectrograph. The field of view of the telescope is ~0.5o. A webcam, also housed close to the entrance optics, records images of the sky in the spectrometer viewing direction at one minute intervals. These images are included in the dataset. Instrument Setup: The spectrometer was scanning wavelength regions in the UV-Vis region with a variable resolution spread over the pixel array CCD. Spectra were taken at multiple viewing angles (1,2,3,4,6,8,15,30,90o) in the open water and (-5,1,2,4,6,8,15,30,90o) in the ice (5th October - left ice) above the horizon. 90o is used as the reference viewing angle. Scattered sunlight was fed into the spectrometer using an optical fibre whose input was placed at the focal point of a lens receiving light from the rotating mirror which was setup to automatically adjust for the roll of the ship to maintain its viewing angle. The data is processed using 2 wavelength fitting regions as follows: M region: 323-348 nm in the UV retrieving: XS1=NO2 x 1e16, XS2=O3 x 1e19, XS6=O4x1e42, XS7=BrOx1e14, XS11 HCHOx1e16, XS12=slope O3 (to improve fit of O3 due to air mass changes with wavelength). And S region (visible) 416-443 nm, retrieving XS1=NO2 x 1e16, XS6=H2O x 1e22, XS7=O4x1e42, XS11=IOx1e14 The entrance optics of the tracker were cleaned daily using kimwipes. The dataset contains the following files: - FPS files, which are binary files generated by in-house software written by The National Institute of Water and Atmosphere (NIWA). - A MAX-DOAS log file, in text format - A MAX-DOAS error file, in text format - A configuration file, in text format

  • The Southern Ocean is one the most significant regions on earth for regulating the build up of anthropogenic CO2 in the atmosphere, and the capacity for carbon uptake in the region could be altered by climate change. The project aims to establish a time series of anthropogenic carbon accumulation. The work will be used to identify processes regulating the CO2 uptake and to test models that predict future uptake. These data were collected on the VMS voyage of the Aurora Australis in the 2010-2011 field season. Data include pH, carbon dioxide, alkalinity and spectrometer data.

  • Owing to the fact that the principal investigator died before data were able to be archived, the only available data are in the form of the referenced paper, which is available as a PDF download to AAD staff only. From the referenced papers: Macquarie Island is an exposure above sea level of the Macquarie Ridge Complex, on the boundary between the Australian and Pacific plates south of New Zealand. Geodynamic reconstructions show that at ca. 12-9.5 Ma, oceanic crust of the Macquarie Island region was created at this plate boundary within a system of short spreading-ridge segments linked by large-offset transform faults. At this time, the spreading rate was slowing (less than 10 mm/yr half-spreading rate) and magmatism was waning. Probably before 5 Ma, and possibly before the extinct spreading ridge had subsided, the plate boundary became obliquely convergent, and crustal blocks were rotated, tilted, and uplifted along the ridge to form the island. Planation by marine erosion has exposed sections through the oceanic crust. The magmatism that built the oceanic crust produced melts similar in composition to the widespread normal to enriched mid-oceanic ridge basalt (N- to E-MORB) suite found in many spreading ridges, but the melts ranged beyond E-MORB to primitive, highly enriched, and silica-undersaturated compositions. These compositions form one end member of a continuum from MORB but seem not to have been derived from a MORB-source mantle, despite sharing a Pacific MORB isotopic signature. The survival of these primitive melts may be due to their origin in a slow-spreading system that must have been closing down as extension along the plate boundary gave way to transpression, putting a stop to the upwelling of asthenosphere and decompression melting. In a more energetic, faster-spreading system, mixing would have been more efficient, the presence of this end member could not easily have been inferred from its isotopic composition, and the igneous rocks would have resembled a typical N- to E-MORB suite. Macquarie Island may therefore provide a type example of magmatism at a very slow spreading ridge and a clue to the origins of E-MORB. Macquarie Island is an exposure above sea-level of part of the crest of the Macquarie Ridge. The ridge marks the Australia-Pacific plate boundary south of New Zealand, where the plate boundary has evolved progressively since Eocene times from an oceanic spreading system into a system of long transform faults linked by short spreading segments, and currently into a right-lateral strike-slip plate boundary. The rocks of Macquarie Island were formed during spreading at this plate boundary in Miocene times, and include intrusive rocks (mantle and cumulate periodites, gabbros, sheeted dolerite dyke complexes), volcanic rocks (N- to E-MORB pillow lavas, picrites, breccias, hyaloclastites), and associated sediments. A set of Macquarie Island basaltic glasses has been analysed by electron microphobe for major elements, S, Cl, and F; by Fourier transform infrared spectroscopy for H2O; by laser ablation-inductively coupled plasma mass spectrometry for trace elements; and by secondary ion mass spectrometry for Sr, Nd and Pb isotopes. Macquarie Island basaltic glasses are divided into two compositional groups according to their mg-number-K2O relationships. Near-primitive basaltic glasses (Group I) have the highest mg-number (63-69), and high Al2O3 and CaO contents at a given K2O content, and carry microphenocrysts of primitive olivine (Fo86-89.5). Their bulk compositions are used to calculate primary melt compositions in equilibrium with the most magnesian Macquarie Island olivines (Fo90.5). Fractionated, Group II, basaltic glasses are saturated with olivine + plagioclase + or - clinopyroxene, and have lower mg-number (57-67), and relatively low Al2O3 and CaO contents. Group I glasses define a seriate variation within the compositional spectrum of MORB, and extend the compositional range from N-MORB compositions to enriched compositions that represent a new primitive enriched MORB end-member. Compared with N-MORB, this new end-member is characterised by relatively low contents of MgO, FeO, SiO2 and CaO, coupled with high contents of Al2O3, TiO2, NaO2, P2O5, K2O and incompatible trace elements, and has the most radiogenic Sr and Pb regional isotope composition. These unusual melt compositions could have been generated by low-degree partial melting of an enriched mantle peridotite source, and were erupted without significant mixing with common -MORB magmas. The mantle in the Macquarie Island region must have been enriched and heterogenous on a very fine scale. We uggest that the mantle enrichment implicated in this study is more likely to be a regional signature that is shared by the Balleny Islands magmatism than directly related to the hypothetical Balleny plume itself.

  • Exopolysaccharide (EPS) is complex sugar made by many microbes in the Antarctic marine environment. This project seeks to understand the ecological role of microbial EPS in the Southern Ocean, where it is known to strongly influence primary production. We will investigate the chemical composition and structure of EPS obtained from Antarctic microbes, which will improve our knowledge of its ecological significance and biotechnological potential. Dataset includes the following: 1) Information on Exopolysaccharide-producing bacterial isolates, isolation sites, media used and growth conditions. 2) 16S rRNA gene sequence and fatty acid data of isolates for strain identification. 3) Exopolysaccharide chemistry data including EPS carbohydrate composition, organic acid composition, sulfate content, molecular weight. 4) Physiology of exopolysaccharide synthesis. Effects of temperature and other factors on EPS yield and glucose conversion efficiency. 5) Iron binding properties. The download file includes: 11 files File 1. Bacterial isolate 16S rRNA gene sequences obtained from Southern Ocean seawater or ice samples. The sequences are all deposited on the GenBank nucleotide (NCBI) database. Sequences are in FASTA format. File 2. Seawater and sea-ice sample information including sites samples, sample type. File 3. Data for exopolysaccharide (EPS)-producing bacteria isolated and subsequently selected for further studied. Information indicates special treatments used to obtain strains including plankton towing, filtration method, and enrichment. Identification to species level was determined by 16S rRNA gene sequence analysis. File 4. EPS-producing bacterial isolate fatty acid content determined using GC/MS procedures. File 5. Basic chemical data for EPS from Antarctic isolates including protein, sulfate, and sugar type relative content (determined by chemical procedures), molecular weight in kilodaltons and polydispersity (determined by gel-based molecular seiving). File 6 Monosaccharide unit composition determined by GC/MS of EPS from Antarctic isolates. File 7. Effect of temperature on culture viscosity and growth of EPS-producing bacterium Pseudoalteromonas sp. CAM025 as affected by temperature. File 8. Effect of temperature on EPS and cell yields and EPS synthesis efficiency (as indicated by glucose consumption) of EPS-producing bacterium Pseudoalteromonas sp. CAM025 as affected by temperature. File 9. Efficiency of copper and cadmium metal ion adsorption onto EPS from EPS-producing bacterium Pseudoalteromonas sp. CAM025. File 10. Phenotypic characteristics data for novel EPS-producing Antarctic strain CAM030. Represents type strain of Olleya marilimosa. File 11. Effect of temperature on chemical make up of EPS from EPS-producing bacterium Pseudoalteromonas sp. CAM025.