scholarly journals The Search for Supernova-Produced Radionuclides in Terrestrial Deep-Sea Archives

2012 ◽  
Vol 29 (2) ◽  
pp. 109-114 ◽  
Author(s):  
J. Feige ◽  
A. Wallner ◽  
S. R. Winkler ◽  
S. Merchel ◽  
L. K. Fifield ◽  
...  
Keyword(s):  
Solar System ◽  
Marine Sediment ◽  
Deep Sea ◽  
Massive Stars ◽  
Sediment Cores ◽  
Deep Ocean ◽  
Transport Mechanisms ◽  
Supernova Shell ◽  
Process Element ◽  
Insight Into

AbstractAn enhanced concentration of 60Fe was found in a deep ocean crust in 2004 in a layer corresponding to an age of ∼2 Myr. The confirmation of this signal in terrestrial archives as supernova-induced and the detection of other supernova-produced radionuclides is of great interest. We have identified two suitable marine sediment cores from the South Australian Basin and estimated the intensity of a possible signal of the supernova-produced radionuclides 26Al, 53Mn, 60Fe, and the pure r-process element 244Pu in these cores. The finding of these radionuclides in a sediment core might allow us to improve the time resolution of the signal and thus to link the signal to a supernova event in the solar vicinity ∼2 Myr ago. Furthermore, it gives us an insight into nucleosynthesis scenarios in massive stars, condensation into dust grains and transport mechanisms from the supernova shell into the solar system.

scholarly journals Ocean and Terrestrial Response to a Pleistocene Warm Interglacial (MIS11) as Revealed by Pollen and Dinoflagellates from Marine Sediment Cores, South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Joseph Graham Prebble
Keyword(s):  
New Zealand ◽  
Marine Sediment ◽  
Deep Sea ◽  
Forest Type ◽  
Sediment Cores ◽  
Pollen Record ◽  
Sea Floor ◽  
Sw Pacific ◽  
Modern Process ◽  
Tasman Sea

<p>The response of the surface ocean and terrestrial climate in the New Zealand region to interglacial Marine Isotope Stage (MIS) 11 (423-380ka) is documented, using assemblages of fossilised marine algae (dinoflagellate cysts, or dinocysts) and spores/pollen from terrestrial plants, analysed from marine sediment cores. This work is underpinned by studies on the modern distribution of dinocysts, factors that influence their accumulation in marine sediment, and the use of dinocyst assemblages to quantify past sea surface temperature (SST). In the first of the modern-process studies, a dataset of modern sea-floor dinocyst assemblages from the Southern Hemisphere is collated, including new observations from the SW Pacific. Variations in the assemblages are related to environmental gradients. Cluster analysis reveals distinct biogeographic assemblage zones, individual taxa indicative of specific water masses are identified, while ordination of the databases indicates that the assemblages vary most with changes in SST. A second modern process study reports on the dinocyst assemblages from two time-incremental sediment traps (3 years of data) moored north and south of the Subtropical Front in the ocean east of New Zealand. This study provides observations of seasonal and inter-annual variability of dinocyst flux to the deep sea, which are used to identify possible biases in the sea-floor dinocyst assemblages. Observations from these first two studies are used in a systematic analysis of the strengths and weakness of using dinocyst assemblages to quantify SST in the SW Pacific. The best transfer function performance achieved was a root mean squared error of 1.47˚C, for an artificial neural network model, and the benefits in considering a range of model results are also established. Fossil records that document the oceanographic and terrestrial response to MIS11 are developed from two areas around New Zealand; (i) dinocysts assemblages are collected from the east Tasman Sea, from giant piston cores MD06-2987, -2988, and 2989, and (ii) dinocysts and pollen assemblages are analysed from Deep Sea Drilling Project (DSDP) Site 594, from the east of New Zealand. Dinocyst assemblages confirm that SST in the east Tasman Sea was ~2-3˚C warmer than the present during late MIS11 (415-400ka), while SSTs were slightly below modern levels during an early phase (428-415ka). Two assemblage – based productivity indices suggest that the elevated SSTs during MIS11 were accompanied by lower rates of primary productivity in the east Tasman Sea study area than the present. As in the east Tasman Sea, two distinct phases of MIS11 are recognised in both the dinocyst and pollen assemblages at DSDP 594. The dinocyst assemblages of late MIS11 are similar to, but qualitatively represent warmer waters than the Holocene. The succession of pollen assemblages during MIS12-11 is very similar to that observed during the previous two interglacials at this site (MIS1 and MIS5), with two notable variations: (i) the deglacial vegetation succession during MIS11 was prolonged, and (ii) the pollen assemblage representing the warmest forest type was also present for longer (ca. 15ky) than later interglacials. Changes in the pollen record during MIS11 at DSDP 594 correlate more closely to SST variations in the east Tasman Sea than to ocean variations at DSDP 594, suggesting that the eastern ocean had only limited influence on conditions on the adjacent landmass during MIS11.</p>

Variable response of North Atlantic deep-sea benthic ecosystems to industrial-era climate change

2021 ◽  
Author(s):  
Charlotte O'Brien ◽  
Peter Spooner ◽  
David Thornalley ◽  
Jack Wharton ◽  
Eirini Papachristopoulou ◽  
...  
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Deep Sea ◽  
Sediment Cores ◽  
Regional Scale ◽  
Deep Ocean ◽  
Variable Response ◽  
The Holocene ◽  
Surface Ocean ◽  
Benthic Ecosystems

&lt;p&gt;&lt;strong&gt;Traditionally, deep-sea ecosystems have been considered to be insulated from the effects of modern climate change. Yet, with the recognition of the importance of food supply from the surface ocean and deep-sea currents to sustaining these systems, the potential for rapid response of benthic systems to climate change is gaining increasing attention. North Atlantic benthic responses to past climate change have been well-documented using marine sediment cores on glacial-interglacial timescales, and ocean sediments have also begun to reveal that planktic species assemblages are already being influenced by global warming. However, very few ecological time-series exist for the deep ocean covering the Holocene-through-industrial era. Here, we use benthic and planktic foraminifera found in Northeast Atlantic (EN539-MC16-A/B and RAPID-17-5P), Northwest Atlantic (KNR158-4-10MC and KNR158-4-9GGC) and Labrador Sea (RAPID-35-25B and RAPID-35-14P) sediments to show that, in locations beneath areas of major North Atlantic surface water change, benthic ecosystems have also changed significantly over the industrial era relative to the Holocene. We find that the response of the benthos is dependent on changes in the surface ocean near to the study sites. Our work highlights the spatial heterogeneity of these benthic ecosystem changes and therefore the need for local-regional scale modelling and observations to better understand responses to deep-sea circulation changes and modern surface climate change.&amp;#160;&lt;/strong&gt;&lt;/p&gt;

scholarly journals Exceptional 20th Century Shifts in Deep-Sea Ecosystems Are Spatially Heterogeneous and Associated With Local Surface Ocean Variability

2021 ◽  
Vol 8 ◽  
Author(s):  
Charlotte L. O’Brien ◽  
Peter T. Spooner ◽  
Jack H. Wharton ◽  
Eirini Papachristopoulou ◽  
Nicolas Dutton ◽  
...  
Keyword(s):  
Climate Change ◽  
Deep Sea ◽  
Sediment Cores ◽  
Regional Scale ◽  
Deep Ocean ◽  
Small Scale ◽  
Surface Ocean ◽  
Spatial Coverage ◽  
Major Surface ◽  
Benthic Ecosystems

Traditionally, deep-sea ecosystems have been considered to be insulated from the effects of modern climate change, but with the recognition of the importance of food supply from the surface ocean and deep-sea currents to sustaining these systems, the potential for rapid response of benthic systems to climate change is gaining increasing attention. However, very few ecological time-series exist for the deep ocean covering the twentieth century. Benthic responses to past climate change have been well-documented using marine sediment cores on glacial-interglacial timescales, and ocean sediments have also begun to reveal that planktic species assemblages are already being influenced by global warming. Here, we use benthic foraminifera found in mid-latitude and subpolar North Atlantic sediment cores to show that, in locations beneath areas of major surface water change, benthic ecosystems have also changed significantly over the last ∼150 years. The maximum benthic response occurs in areas which have seen large changes in surface circulation, temperature, and/or productivity. We infer that the observed surface-deep ocean coupling is due to changes in the supply of organic matter exported from the surface ocean and delivered to the seafloor. The local-to-regional scale nature of these changes highlights that accurate projections of changes in deep-sea ecosystems will require (1) increased spatial coverage of deep-sea proxy records, and (2) models capable of adequately resolving these relatively small-scale oceanographic features.

Deep Sea Ostracodes and Climate Change

2003 ◽  
Vol 9 ◽  
pp. 247-264 ◽  
Author(s):  
Thomas M. Cronin ◽  
Gary S. Dwyer
Keyword(s):  
Climate Change ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Global Climate ◽  
Sediment Cores ◽  
Deep Ocean ◽  
Bottom Water Temperature ◽  
Shell Chemistry ◽  
Practical Guidelines ◽  
Deep Ocean Circulation

Ostracodes are bivalved Crustacea whose fossil shells constitute the most abundant and diverse metazoan group preserved in sediment cores from deep and intermediate ocean water depths. The ecology, zoogeography, and shell chemistry of many ostracode taxa makes them useful for paleoceanographic research on topics ranging from deep ocean circulation, bottom-water temperature, ecological response to global climate change and many others. However, the application of ostracodes to the study of climate change has been hampered by a number of factors, including the misconception that they are rare or absent in deep-sea sediments and the lack of taxonomic and zoogeographic data. In recent years studies from the Atlantic, Pacific, and Arctic Oceans show that ostracodes are abundant enough for quantitative assemblage analysis and that the geochemistry of their shells can be a valuable tool for paleotemperature reconstruction. This paper presents practical guidelines for using ostracodes in investigations of climate-driven ocean variability and the ecological and evolutionary impacts of these changes.

scholarly journals Microbiomes of hadal fishes contain similar taxa, obligate symbionts, and known piezophiles across trench habitats

2022 ◽  
Author(s):  
Jessica M Blanton ◽  
Logan M Peoples ◽  
Mackenzie E Gerringer ◽  
Caroline M Iacuniello ◽  
Natalya D Gallo ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Hydrostatic Pressure ◽  
Microbial Communities ◽  
Deep Sea ◽  
Deep Ocean ◽  
Amplicon Sequencing ◽  
Rrna Gene ◽  
Mariana Trench ◽  
Geographic Separation ◽  
Insight Into

Hadal snailfishes are the deepest-living fishes in the ocean, inhabiting trenches from depths of ~6,000 to 8,000 m. While the microbial communities in trench environments have begun to be characterized, the microbes associated with hadal megafauna remain relatively unknown. Here, we describe the gut microbiomes of two hadal snailfishes, Pseudoliparis swirei (Mariana Trench) and Notoliparis kermadecensis (Kermadec Trench) using 16S rRNA gene amplicon sequencing. We contextualize these microbiomes with comparisons to the abyssal macrourid Coryphaenoides yaquinae and the continental shelf-dwelling snailfish Careproctus melanurus. The microbial communities of the hadal snailfishes were distinct from their shallower counterparts and were dominated by the same sequences related to the Mycoplasmataceae and Desulfovibrionaceae. These shared taxa indicate that symbiont lineages may have remained similar to the ancestral symbiont since their geographic separation or that they are dispersed between geographically distant trenches and subsequently colonize specific hosts. The abyssal and hadal fishes contained sequences related to known, cultured piezophiles, microbes that grow optimally under high hydrostatic pressure, including Psychromonas, Moritella, and Shewanella. These taxa are adept at colonizing nutrient-rich environments present in the deep ocean, such as on particles and in the guts of hosts, and we hypothesize they could make a dietary contribution to deep-sea fishes by degrading chitin and producing fatty acids. We characterize the gut microbiota within some of the deepest fishes to provide new insight into the diversity and distribution of host-associated microbial taxa and the potential of these animals, and the microbes they harbor, for understanding adaptation to deep-sea habitats.

scholarly journals Ocean and Terrestrial Response to a Pleistocene Warm Interglacial (MIS11) as Revealed by Pollen and Dinoflagellates from Marine Sediment Cores, South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Joseph Graham Prebble
Keyword(s):  
New Zealand ◽  
Marine Sediment ◽  
Deep Sea ◽  
Forest Type ◽  
Sediment Cores ◽  
Pollen Record ◽  
Sea Floor ◽  
Sw Pacific ◽  
Modern Process ◽  
Tasman Sea

<p>The response of the surface ocean and terrestrial climate in the New Zealand region to interglacial Marine Isotope Stage (MIS) 11 (423-380ka) is documented, using assemblages of fossilised marine algae (dinoflagellate cysts, or dinocysts) and spores/pollen from terrestrial plants, analysed from marine sediment cores. This work is underpinned by studies on the modern distribution of dinocysts, factors that influence their accumulation in marine sediment, and the use of dinocyst assemblages to quantify past sea surface temperature (SST). In the first of the modern-process studies, a dataset of modern sea-floor dinocyst assemblages from the Southern Hemisphere is collated, including new observations from the SW Pacific. Variations in the assemblages are related to environmental gradients. Cluster analysis reveals distinct biogeographic assemblage zones, individual taxa indicative of specific water masses are identified, while ordination of the databases indicates that the assemblages vary most with changes in SST. A second modern process study reports on the dinocyst assemblages from two time-incremental sediment traps (3 years of data) moored north and south of the Subtropical Front in the ocean east of New Zealand. This study provides observations of seasonal and inter-annual variability of dinocyst flux to the deep sea, which are used to identify possible biases in the sea-floor dinocyst assemblages. Observations from these first two studies are used in a systematic analysis of the strengths and weakness of using dinocyst assemblages to quantify SST in the SW Pacific. The best transfer function performance achieved was a root mean squared error of 1.47˚C, for an artificial neural network model, and the benefits in considering a range of model results are also established. Fossil records that document the oceanographic and terrestrial response to MIS11 are developed from two areas around New Zealand; (i) dinocysts assemblages are collected from the east Tasman Sea, from giant piston cores MD06-2987, -2988, and 2989, and (ii) dinocysts and pollen assemblages are analysed from Deep Sea Drilling Project (DSDP) Site 594, from the east of New Zealand. Dinocyst assemblages confirm that SST in the east Tasman Sea was ~2-3˚C warmer than the present during late MIS11 (415-400ka), while SSTs were slightly below modern levels during an early phase (428-415ka). Two assemblage – based productivity indices suggest that the elevated SSTs during MIS11 were accompanied by lower rates of primary productivity in the east Tasman Sea study area than the present. As in the east Tasman Sea, two distinct phases of MIS11 are recognised in both the dinocyst and pollen assemblages at DSDP 594. The dinocyst assemblages of late MIS11 are similar to, but qualitatively represent warmer waters than the Holocene. The succession of pollen assemblages during MIS12-11 is very similar to that observed during the previous two interglacials at this site (MIS1 and MIS5), with two notable variations: (i) the deglacial vegetation succession during MIS11 was prolonged, and (ii) the pollen assemblage representing the warmest forest type was also present for longer (ca. 15ky) than later interglacials. Changes in the pollen record during MIS11 at DSDP 594 correlate more closely to SST variations in the east Tasman Sea than to ocean variations at DSDP 594, suggesting that the eastern ocean had only limited influence on conditions on the adjacent landmass during MIS11.</p>

scholarly journals Environmental DNA preserved in marine sediment for detecting jellyfish blooms after a tsunami

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mizuki Ogata ◽  
Reiji Masuda ◽  
Hiroya Harino ◽  
Masayuki K. Sakata ◽  
Makoto Hatakeyama ◽  
...  
Keyword(s):  
Marine Sediment ◽  
Oil Spills ◽  
Sediment Cores ◽  
Environmental Dna ◽  
Target Species ◽  
Tank Experiment ◽  
Polycyclic Aromatic ◽  
Flow Through ◽  
High Concentrations ◽  
One Year

AbstractEnvironmental DNA (eDNA) can be a powerful tool for detecting the distribution and abundance of target species. This study aimed to test the longevity of eDNA in marine sediment through a tank experiment and to use this information to reconstruct past faunal occurrence. In the tank experiment, juvenile jack mackerel (Trachurus japonicus) were kept in flow-through tanks with marine sediment for two weeks. Water and sediment samples from the tanks were collected after the removal of fish. In the field trial, sediment cores were collected in Moune Bay, northeast Japan, where unusual blooms of jellyfish (Aurelia sp.) occurred after a tsunami. The samples were analyzed by layers to detect the eDNA of jellyfish. The tank experiment revealed that after fish were removed, eDNA was not present in the water the next day, or subsequently, whereas eDNA was detectable in the sediment for 12 months. In the sediment core samples, jellyfish eDNA was detected at high concentrations above the layer with the highest content of polycyclic aromatic hydrocarbons, reflecting tsunami-induced oil spills. Thus, marine sediment eDNA preserves a record of target species for at least one year and can be used to reconstruct past faunal occurrence.

An Insight into the Polymeric Nanoparticles Applications in Diabetes Diagnosis and Treatment

2021 ◽  
Vol 21 ◽  
Author(s):  
Parisa Dehghani ◽  
Monireh Esameili Rad ◽  
Atefeh Zarepour ◽  
Ponnurengam Malliappan Sivakumar ◽  
Ali Zarrabi
Keyword(s):  
Polymeric Nanoparticles ◽  
Synthetic Polymers ◽  
Diagnostic Methods ◽  
Diagnosis And Treatment ◽  
Diabetes Diagnosis ◽  
Transport Mechanisms ◽  
Different Types ◽  
Treatment And Diagnosis ◽  
Insight Into

: Diabetes mellitus (DM) is a type of chronic metabolic disease that has affected millions of people worldwide and is known with a defect in the amount of insulin secretion, insulin functions, or both. This deficiency leads to an increase in the amounts of glucose, which could be accompanied by long-term damages to other organs such as eyes, kidneys, heart, and nervous system. Thus, introducing an appropriate approach for diagnosis and treatment of different types of DM is the aim of several researches. By the emergence of nanotechnology and its application in medicine, new approaches were presented for these purposes. The object of this review article is to introduce different types of polymeric nanoparticles (PNPs), as one of the most important classes of nanoparticles, for diabetic management. To achieve this goal, at first, some of the conventional therapeutic and diagnostic methods of DM will be reviewed. Then, different types of PNPs, in two forms of natural and synthetic polymers with different properties, as a new method for DM treatment and diagnosis will be introduced. In the next section, the transport mechanisms of these types of nano-carriers across the epithelium, via paracellular and transcellular pathways will be explained. Finally, the clinical use of PNPs in the treatment and diagnosis of DM will be summarized. Based on the results of this literature review, PNPs could be considered one of the most promising methods for DM management.

scholarly journals Remotely distinguishing and mapping endogenic water on the Moon

2017 ◽  
Vol 375 (2094) ◽  
pp. 20150391 ◽  
Author(s):  
Rachel L. Klima ◽  
Noah E. Petro
Keyword(s):  
Solar Wind ◽  
Spatial Distribution ◽  
Solar System ◽  
The Moon ◽  
Testing Hypotheses ◽  
Origin And Evolution ◽  
Lunar Interior ◽  
Geological Features ◽  
Insight Into

Water and/or hydroxyl detected remotely on the lunar surface originates from several sources: (i) comets and other exogenous debris; (ii) solar-wind implantation; (iii) the lunar interior. While each of these sources is interesting in its own right, distinguishing among them is critical for testing hypotheses for the origin and evolution of the Moon and our Solar System. Existing spacecraft observations are not of high enough spectral resolution to uniquely characterize the bonding energies of the hydroxyl molecules that have been detected. Nevertheless, the spatial distribution and associations of H, OH − or H 2 O with specific lunar lithologies provide some insight into the origin of lunar hydrous materials. The global distribution of OH − /H 2 O as detected using infrared spectroscopic measurements from orbit is here examined, with particular focus on regional geological features that exhibit OH − /H 2 O absorption band strengths that differ from their immediate surroundings. This article is part of the themed issue ‘The origin, history and role of water in the evolution of the inner Solar System’.

Sign in / Sign up

Export Citation Format

Share Document