scholarly journals The Geochemistry of Pāua as a Potential Proxy for Past and Present Environmental Change

2021 ◽  
Author(s):  
◽  
Ramona Mahia White
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
High Resolution ◽  
Temporal Resolution ◽  
Environmental Conditions ◽  
Winter Season ◽  
High Temporal Resolution ◽  
Nacreous Layer ◽  
Prismatic Layer ◽  
Icp Ms

<p>Nearshore New Zealand mollusca (shellfish) have the potential to be important archives of environmental conditions and change. Ambient ocean chemistry can be incorporated into the calcium carbonate (CaCO3) shell during the life span of the mollusc providing a high resolution temporal record of the chemical and physical changes of the environments the mollusc lived in. Previous studies on foraminifera and coral have shown that the substitution of magnesium or strontium for calcium (Mg, Sr/Ca) during the formation of the CaCO3 shell is directly correlated with ocean temperatures. Other divalent cations (e.g., Sr2+, Ba2+, Pb2+) can also provide information on ambient salinity, primary productivity or nutrient levels, and local anthropogenic pollution. This study uses new geochemical techniques that have been developed to measure the trace element chemistry of CaCO3 mollusc shells at high temporal resolution, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in order to calibrate shell chemistry with environmental conditions. This study is the first to explore the use of the geochemistry of Haliotis iris as a potential proxy for (paleo-) environmental conditions. Pāua (Haliotis iris) were collected from six different localities around New Zealand and the Chatham Islands as well as a cultured environment (OceaNZ Blue Ltd). The shells were sectioned following the axis of maximum growth exposing both CaCO3 layers; the prismatic (predominantly calcite) and nacreous (aragonite) layers. The shells were analysed by LA-ICP-MS at 25 μm spot sizes through a high temporal transect of both layers. Observed differences in the element/Ca ratios between the prismatic and nacreous layer reflect the differing crystallinity of each layer. High temporal resolution Mg/Ca ratio data of the prismatic layer of the samples which grew in a cultured environment were compared with temperature and growth data supplied by OceaNZ Blue Ltd. The results showed that temperature was not the primary control on the uptake of Mg within the shells and that influences from biological factors including increased growth rate were also evident. Sr/Ca ratios show a weak inverse relationship with increased growth rate assumed. These results, however, are not reproducible within samples collected from the wild, showing that external factors (high wave energy, diet, predation, lack of food) place metabolic stress on the pāua. The monitoring of other element/Ca including Ba/Ca, Al/Ca, Pb/Ca and Zn/Ca ratios have the potential to provide information into the past frequency of storm events that deliver sediment into the oceans and remobilise other sediments and changing levels of environmental pollution. This is reflected through increased Al/Ca, Pb/Ca and Zn/Ca ratios during the winter season in a number of samples (n = 3) gained from the high resolution analysis of the prismatic layers. Overall, element/Ca ratios are difficult to correlate environmental conditions in samples from the wild as there are many different parameters influencing the uptake of element/Ca ratios with the shells of pāua. Uncertainties lie with a lack of understanding of the biological controls influencing pāua during biomineralisation including the transportation of the elements within organism to the extrapallial fluid to be biomineralised, ontogeny, and the rate and regularity of biomineralisation of shell material.</p>

scholarly journals The Geochemistry of Pāua as a Potential Proxy for Past and Present Environmental Change

2021 ◽  
Author(s):  
◽  
Ramona Mahia White
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
High Resolution ◽  
Temporal Resolution ◽  
Environmental Conditions ◽  
Winter Season ◽  
High Temporal Resolution ◽  
Nacreous Layer ◽  
Prismatic Layer ◽  
Icp Ms

<p>Nearshore New Zealand mollusca (shellfish) have the potential to be important archives of environmental conditions and change. Ambient ocean chemistry can be incorporated into the calcium carbonate (CaCO3) shell during the life span of the mollusc providing a high resolution temporal record of the chemical and physical changes of the environments the mollusc lived in. Previous studies on foraminifera and coral have shown that the substitution of magnesium or strontium for calcium (Mg, Sr/Ca) during the formation of the CaCO3 shell is directly correlated with ocean temperatures. Other divalent cations (e.g., Sr2+, Ba2+, Pb2+) can also provide information on ambient salinity, primary productivity or nutrient levels, and local anthropogenic pollution. This study uses new geochemical techniques that have been developed to measure the trace element chemistry of CaCO3 mollusc shells at high temporal resolution, using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in order to calibrate shell chemistry with environmental conditions. This study is the first to explore the use of the geochemistry of Haliotis iris as a potential proxy for (paleo-) environmental conditions. Pāua (Haliotis iris) were collected from six different localities around New Zealand and the Chatham Islands as well as a cultured environment (OceaNZ Blue Ltd). The shells were sectioned following the axis of maximum growth exposing both CaCO3 layers; the prismatic (predominantly calcite) and nacreous (aragonite) layers. The shells were analysed by LA-ICP-MS at 25 μm spot sizes through a high temporal transect of both layers. Observed differences in the element/Ca ratios between the prismatic and nacreous layer reflect the differing crystallinity of each layer. High temporal resolution Mg/Ca ratio data of the prismatic layer of the samples which grew in a cultured environment were compared with temperature and growth data supplied by OceaNZ Blue Ltd. The results showed that temperature was not the primary control on the uptake of Mg within the shells and that influences from biological factors including increased growth rate were also evident. Sr/Ca ratios show a weak inverse relationship with increased growth rate assumed. These results, however, are not reproducible within samples collected from the wild, showing that external factors (high wave energy, diet, predation, lack of food) place metabolic stress on the pāua. The monitoring of other element/Ca including Ba/Ca, Al/Ca, Pb/Ca and Zn/Ca ratios have the potential to provide information into the past frequency of storm events that deliver sediment into the oceans and remobilise other sediments and changing levels of environmental pollution. This is reflected through increased Al/Ca, Pb/Ca and Zn/Ca ratios during the winter season in a number of samples (n = 3) gained from the high resolution analysis of the prismatic layers. Overall, element/Ca ratios are difficult to correlate environmental conditions in samples from the wild as there are many different parameters influencing the uptake of element/Ca ratios with the shells of pāua. Uncertainties lie with a lack of understanding of the biological controls influencing pāua during biomineralisation including the transportation of the elements within organism to the extrapallial fluid to be biomineralised, ontogeny, and the rate and regularity of biomineralisation of shell material.</p>

Boron isotope analysis of coral skeletons by laser ablation MC-ICP-MS: new insights into calcification and environmental reconstruction at high temporal resolution

2020 ◽  
Author(s):  
Gavin L. Foster ◽  
Thomas B. Chalk ◽  
Christopher D. Standish
Keyword(s):  
Laser Ablation ◽  
Trace Element ◽  
Temporal Resolution ◽  
Isotope Analysis ◽  
Coral Skeleton ◽  
Boron Isotope ◽  
High Temporal Resolution ◽  
Carbonate System ◽  
Seawater Ph ◽  
Icp Ms

&lt;p&gt;Despite being some of the largest bio-constructions on the planet, coral reefs are made by many millions of cm- to mm-sized polyps of Scleractinian corals. Calcification occurs in a micron sized space sandwiched between the coral animal and the existing skeleton, known as the extra cellular medium (ECM). The coral animal has a tight control on the carbonate system in this space through deploying enzymatic pumps (e.g. Ca-ATPase) and secreting acidic-rich proteins. Tracking the state of the carbonate system in the ECM is therefore key to forming a mechanistic understanding of how environmental change, such as ocean acidification, influences skeletal formation and ultimately the growth and resilience of these important ecosystems.&lt;/p&gt;&lt;p&gt;Traditional means to examine ECM composition is through the use of micro-electrodes. While these approaches have revealed many key insights they are, by their nature, invasive.&amp;#160; They also only provide snap shots of information for corals grown in the laboratory. The boron isotopic composition of the coral skeleton and its boron content (expressed as B/Ca ratio) have recently emerged as a viable alternative approach to fully characterise the carbonate system in the ECM.&amp;#160; However, most studies employ bulk sampling techniques which require averaging across both structural elements of the coral skeleton and many months to years of growth. Laser ablation MC-ICP-MS approaches are now available as an alternative sampling protocol (e.g. Standish et al. 2019), and along with B/Ca (and other trace element) measurements this not only allows a reconstruction of the full carbonate system of the ECM from an analysis of the skeleton of any coral (cultured or wild) at unprecedented spatial and temporal resolution, but it also allows an examination of the influence of the carbonate system in the ECM on trace element incorporation.&amp;#160;&lt;/p&gt;&lt;p&gt;Here we present boron isotope and trace element analyses of several tropical, reef-building, corals to examine the nature and magnitude of fine scale variation in ECM composition.&amp;#160; By studying corals from locations where external seawater is well known we also gain insights into trace element incorporation and whether external seawater pH can be accurately reconstructed from the boron-based proxies at weekly (or better) resolution.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Standish, C.D., Chalk, T.B., Babila, T.L., Milton, J.A., Palmer, M.R., Foster, G.L. (2019) The effect of matrix interferences in situ boron isotope analysis by laser ablation MC-ICP-MS, Rapid Communications in Mass Spectrometry 33: 959&amp;#8211;968 https://doi.org/10.1002/rcm.8432&lt;/p&gt;

scholarly journals The impact of GPS and high-resolution radiosonde nudging on the simulation of heavy precipitation during HyMeX IOP6

2021 ◽  
Author(s):  
Alberto Caldas-Alvarez ◽  
Samiro Khodayar ◽  
Peter Knippertz
Keyword(s):  
High Resolution ◽  
Temporal Resolution ◽  
Hydrological Cycle ◽  
Weather Prediction ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Small Scale ◽  
High Temporal Resolution ◽  
The Impact

Abstract. Heavy precipitation is one of the most devastating weather extremes in the western Mediterranean region. Our capacity to prevent negative impacts from such extreme events requires advancements in numerical weather prediction, data assimilation and new observation techniques. In this paper we investigate the impact of two state-of-the-art data sets with very high resolution, Global Positioning System-Zenith Total Delays (GPS-ZTD) with a 10 min temporal resolution and radiosondes with ~700 levels, on the representation of convective precipitation in nudging experiments. Specifically, we investigate whether the high temporal resolution, quality, and coverage of GPS-ZTDs can outweigh their lack of vertical information or if radiosonde profiles are more valuable despite their scarce coverage and low temporal resolution (24 h to 6 h). The study focuses on the Intensive Observation Period 6 (IOP6) of the Hydrological Cycle in the Mediterranean eXperiment (HyMeX; 24 September 2012). This event is selected due to its severity (100 mm/12 h), the availability of observations for nudging and validation, and the large observation impact found in preliminary sensitivity experiments. We systematically compare simulations performed with the COnsortium for Small scale MOdelling (COSMO) model assimilating GPS, high- and low vertical resolution radiosoundings in model resolutions of 7 km, 2.8 km and 500 m. The results show that the additional GPS and radiosonde observations cannot compensate errors in the model dynamics and physics. In this regard the reference COSMO runs have an atmospheric moisture wet bias prior to precipitation onset but a negative bias in rainfall, indicative of deficiencies in the numerics and physics, unable to convert the moisture excess into sufficient precipitation. Nudging GPS and high-resolution soundings corrects atmospheric humidity, but even further reduces total precipitation. This case study also demonstrates the potential impact of individual observations in highly unstable environments. We show that assimilating a low-resolution sounding from Nimes (southern France) while precipitation is taking place induces a 40 % increase in precipitation during the subsequent three hours. This precipitation increase is brought about by the moistening of the 700  hPa level (7.5 g kg−1) upstream of the main precipitating systems, reducing the entrainment of dry air above the boundary layer. The moist layer was missed by GPS observations and high-resolution soundings alike, pointing to the importance of profile information and timing. However, assimilating GPS was beneficial for simulating the temporal evolution of precipitation. Finally, regarding the scale dependency, no resolution is particularly sensitive to a specific observation type, however the 2.8 km run has overall better scores, possibly as this is the optimally tuned operational version of COSMO. In follow-up experiments the Icosahedral Nonhydrostatic Model (ICON) will be investigated for this case study to assert whether its numerical and physics updates, compared to its predecessor COSMO, are able to improve the quality of the simulations.

scholarly journals Rapid Lipolytic Oscillations in Ex-Vivo Adipose Tissue Explants Revealed Through Microfluidic Droplet Sampling at High Temporal Resolution

2019 ◽  
Author(s):  
Juan Hu ◽  
xiangpeng li ◽  
Robert L. Judd ◽  
Christopher Easley
Keyword(s):  
Adipose Tissue ◽  
High Resolution ◽  
Temporal Resolution ◽  
Ex Vivo ◽  
Analytical Framework ◽  
Tissue Level ◽  
Droplet Microfluidics ◽  
Biological Information ◽  
High Temporal Resolution ◽  
Tissue Explants

Our understanding of adipose tissue biology has steadily evolved. While structural and energy storage functionalities have been in the forefront, a key endocrine role for adipocytes was revealed only over the last few decades. In contrast to the wealth of information on dynamic function of other endocrine tissues, few studies have focused on dynamic adipose tissue function or on tool development toward that end. Here, we apply our unique droplet-based microfluidic devices to culture, perfuse, and sample secretions from primary murine epididymal white adipose tissue (eWAT), and from predifferentiated clusters of 3T3-L1 adipocytes. Through automated control, oil-segmented aqueous droplets (~2.6 nL) were sampled from tissue or cells at 3.5-second temporal resolution, with integrated enzyme assays enabling real-time quantification of glycerol (down to 1.9 fmol droplet<sup>-1</sup>). This high resolution revealed previously unreported oscillations in secreted glycerol at frequencies of 0.2 to 2.0 min<sup>-1</sup> (~30-300 s periods) present in the primary tissue but not in clustered cells. Low-level bursts (~50 fmol) released in basal conditions were contrasted with larger bursts (~300 fmol) during stimulation. Further, both fold changes and burst magnitudes were decreased in eWAT of aged and obese mice. These results, combined with immunostaining and photobleaching analyses, suggest that gap-junctional coupling or nerve cell innervation within the intact ex-vivo tissue explants play important roles in this apparent tissue-level, lipolytic synchronization. High-resolution, quantitative sampling by droplet microfluidics thus permitted unique biological information to be observed, giving an analytical framework poised for future studies of dynamic oscillatory function of adipose and other tissues.

scholarly journals Analysis of Finnish blue mussel (Mytilus edulis L.) shell: Biomineral ultrastructure, organic-rich interfacial matrix and mechanical behavior

2019 ◽  
Author(s):  
Pezhman Mohammadi ◽  
Wolfgang Wagermaier ◽  
Merja Penttila ◽  
Markus B. Linder
Keyword(s):  
Mechanical Properties ◽  
High Resolution ◽  
Mytilus Edulis ◽  
Blue Mussel ◽  
Protein Analysis ◽  
Nacreous Layer ◽  
X Ray Diffraction ◽  
Prismatic Layer ◽  
Microscopy Imaging ◽  
X Ray

AbstractStudying various marine biomineralized ultrastructures reveals the appearance of common architectural designs and building blocks in materials with fascinating mechanical properties that match perfectly to their biological tasks. Advanced mechanical properties of biological materials are attributed to evolutionary optimized molecular architectures and structural hierarchy. One example which has not yet been structurally investigated in great detail is the shell of Mytilus edulis L. (Finnish blue mussel) found in the archipelago of SW-Finland. Through a combination of various state-of-the-art techniques such as high-resolution electron microscopy imaging, Fourier-transformed infrared spectroscopy, powder X-ray diffraction, synchrotron wide-angle X-ray diffraction, nanoindentation and protein analysis, both the inorganic mineralized components as well as the organic-rich matrix were extensively characterized. We found very similar ultra-architecture across the shell of M. edulis L. as compared to the widely studied and closely related M. edulis. However, we also found interesting differences, for instance in the thickness and degree of orientation of the mineralized layers indicating dissimilar properties and related alterations in the biomineralization processes. Our results show that the shell of M. edulis L. has a gradient of mechanical properties, with the increase in the stiffness and the hardness from anterior to the posterior region of the shell. The shell is made from distinct and recognizable mineralized layers each varying in thickness and microstructural features. At posterior regions of the shell, moving from dorsal to ventral side, these layers are an oblique prismatic layer, a prismatic layer and a nacreous layer, in which the oblique prismatic layer is found to be the main and thickest mineralized layer of the shell. Probing the calcified rods in the oblique prismatic layer using high resolution SEM imaging revealed opening of channels with a diameters of 40-50 nm and lengths up to a micrometer extending through the rods. The chitin and protein have been found to be the main component of the organic-rich interfacial matrix as expected. Protein analysis showed two abundant proteins with sizes around 100 kD and 45 kD which likely not only regulates biomineralization and adhesion of the crystals but also governing the intrinsic-extrinsic toughening in the shell. Overall, this detailed analysis provides new structural insights into biomineralization of marine shells in general.

scholarly journals Sr-isotope analysis of speleothems by LA-MC-ICP-MS: High temporal resolution and fast data acquisition

2017 ◽  
Vol 468 ◽  
pp. 63-74 ◽  
Author(s):  
Michael Weber ◽  
Jasper A. Wassenburg ◽  
Klaus Peter Jochum ◽  
Sebastian F.M. Breitenbach ◽  
Jessica Oster ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Temporal Resolution ◽  
Isotope Analysis ◽  
High Temporal Resolution ◽  
Sr Isotope ◽  
Fast Data Acquisition ◽  
Icp Ms

High spatial and temporal resolution land surface temperature for the Antarctic Dry Valleys

2020 ◽  
Author(s):  
Maite Lezama Valdes ◽  
Marwan Katurji ◽  
Hanna Meyer
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
Land Surface Temperature ◽  
Land Surface ◽  
High Temporal Resolution ◽  
Dry Valleys ◽  
Model Complex ◽  
The Antarctic

&lt;p&gt;Anthropogenic Climate Change is expected to take a toll on the Antarctic environment and its biodiversity, which is concentrated on the continent&amp;#8217;s few ice-free areas, such as the McMurdo Dry Valleys (MDV). To model the current terrestrial habitat distribution and predict possible climate induced changes, high spatial and temporal resolution abiotic variables, especially land surface temperature (LST) and soil moisture are needed, but are currently unavailable.&lt;/p&gt;&lt;p&gt;The aim of this project is to fill this gap and create a high resolution LST dataset of the Antarctic Dry Valleys. This variable is acquired in a high temporal resolution (sub-daily) by the MODIS sensor aboard Terra and Aqua satellites. However, as LST varies greatly in space, the spatial resolution provided by this data source (1000 m) is too low to give a meaningful impression of LST and to study biodiversity patterns. Therefore, we use data from Landsat and ASTER sensors as a reference to downscale MODIS LST to a spatial resolution of 30 m. 7 year&amp;#8217;s worth of satellite data as well as terrain-derived auxiliary variables went into the development of the model, which predicts 30 m LST for the Antarctic Dry Valleys.&amp;#160;&lt;/p&gt;&lt;p&gt;To model complex relations between terrain, radiation, land cover and LST, machine learning models are used. Multiple algorithms (Random Forest, NN, SVM, Gradient Boosting) are compared to find the best approach for predicting high resolution LST based on MODIS data.&amp;#160;Using the best performing model, a daily dataset is created that provides LST for the Antarctic Dry Valleys from 2002 on.&lt;/p&gt;

scholarly journals High-resolution alkenone palaeobarometry indicates relatively stable p CO 2 during the Pliocene (3.3–2.8 Ma)

2013 ◽  
Vol 371 (2001) ◽  
pp. 20130094 ◽  
Author(s):  
Marcus P. S. Badger ◽  
Daniela N. Schmidt ◽  
Andreas Mackensen ◽  
Richard D. Pancost
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Temporal Resolution ◽  
Sea Surface ◽  
High Temporal Resolution ◽  
Ocean Drilling Program ◽  
Ocean Drilling ◽  
Temperature Reconstructions ◽  
Sensitivity Studies

Temperature reconstructions indicate that the Pliocene was approximately 3 ° C warmer globally than today, and several recent reconstructions of Pliocene atmospheric CO 2 indicate that it was above pre-industrial levels and similar to those likely to be seen this century. However, many of these reconstructions have been of relatively low temporal resolution, meaning that these records may have failed to capture variations associated with the 41 kyr glacial–interglacial cycles thought to have operated in the Pliocene. Here we present a new, high temporal resolution alkenone carbon isotope-based record of p CO 2 spanning 3.3–2.8 Ma from Ocean Drilling Program Site 999. Our record is of high enough resolution (approx. 19 kyr) to resolve glacial–interglacial changes beyond the intrinsic uncertainty of the proxy method. The record suggests that Pliocene CO 2 levels were relatively stable, exhibiting variation less than 55 ppm. We perform sensitivity studies to investigate the possible effect of changing sea surface temperature (SST), which highlights the importance of accurate and precise SST reconstructions for alkenone palaeobarometry, but demonstrate that these uncertainties do not affect our conclusions of relatively stable p CO 2 levels during this interval.

scholarly journals Dimensional characterization of gold nanorods by combining millisecond and microsecond temporal resolution single particle ICP-MS measurements

2017 ◽  
Vol 32 (12) ◽  
pp. 2455-2462 ◽  
Author(s):  
Ildikó Kálomista ◽  
Albert Kéri ◽  
Ditta Ungor ◽  
Edit Csapó ◽  
Imre Dékány ◽  
...  
Keyword(s):  
Dimensional Analysis ◽  
Temporal Resolution ◽  
Gold Nanorods ◽  
Single Particle ◽  
High Temporal Resolution ◽  
Icp Ms ◽  
Resolution Single

By combining normal and high temporal resolution spICP-MS measurements, the accurate dimensional analysis of nanorods is possible.

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