scholarly journals The Southern Ocean diatom Pseudo-nitzschia subcurvata flourished better under simulated glacial than interglacial ocean conditions: Combined effects of CO2 and iron

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260649
Author(s):  
Anna Pagnone ◽  
Florian Koch ◽  
Franziska Pausch ◽  
Scarlett Trimborn
Keyword(s):  
Southern Ocean ◽  
Primary Productivity ◽  
Climatic Conditions ◽  
The Other ◽  
Combined Effects ◽  
Dust Deposition ◽  
Carbon Export ◽  
Negative Effect ◽  
Ocean Conditions ◽  
Fe Addition

The ‘Iron Hypothesis’ suggests a fertilization of the Southern Ocean by increased dust deposition in glacial times. This promoted high primary productivity and contributed to lower atmospheric pCO2. In this study, the diatom Pseudo-nitzschia subcurvata, known to form prominent blooms in the Southern Ocean, was grown under simulated glacial and interglacial climatic conditions to understand how iron (Fe) availability (no Fe or Fe addition) in conjunction with different pCO2 levels (190 and 290 μatm) influences growth, particulate organic carbon (POC) production and photophysiology. Under both glacial and interglacial conditions, the diatom grew with similar rates. In comparison, glacial conditions (190 μatm pCO2 and Fe input) favored POC production by P. subcurvata while under interglacial conditions (290 μatm pCO2 and Fe deficiency) POC production was reduced, indicating a negative effect caused by higher pCO2 and low Fe availability. Under interglacial conditions, the diatom had, however, thicker silica shells. Overall, our results show that the combination of higher Fe availability with low pCO2, present during the glacial ocean, was beneficial for the diatom P. subcurvata, thus contributing more to primary production during glacial compared to interglacial times. Under the interglacial ocean conditions, on the other hand, the diatom could have contributed to higher carbon export due to its higher degree of silicification.

scholarly journals Southern Ocean carbon export efficiency in relation to temperature and primary productivity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gaojing Fan ◽  
Zhengbing Han ◽  
Wentao Ma ◽  
Shuangling Chen ◽  
Fei Chai ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Primary Productivity ◽  
Carbon Export ◽  
Ocean Carbon

scholarly journals A circumpolar dust conveyor in the glacial Southern Ocean

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Torben Struve ◽  
Katharina Pahnke ◽  
Frank Lamy ◽  
Marc Wengler ◽  
Philipp Böning ◽  
...  
Keyword(s):  
South America ◽  
Southern Ocean ◽  
Net Primary Production ◽  
South Pacific ◽  
Dust Deposition ◽  
Carbon Export ◽  
Transport Pathways ◽  
Dust Transport ◽  
Glacial Periods ◽  
Central South

Abstract The increased flux of soluble iron (Fe) to the Fe-deficient Southern Ocean by atmospheric dust is considered to have stimulated the net primary production and carbon export, thus promoting atmospheric CO2 drawdown during glacial periods. Yet, little is known about the sources and transport pathways of Southern Hemisphere dust during the Last Glacial Maximum (LGM). Here we show that Central South America (~24‒32°S) contributed up to ~80% of the dust deposition in the South Pacific Subantarctic Zone via efficient circum-Antarctic dust transport during the LGM, whereas the Antarctic Zone was dominated by dust from Australia. This pattern is in contrast to the modern/Holocene pattern, when South Pacific dust fluxes are thought to be primarily supported by Australian sources. Our findings reveal that in the glacial Southern Ocean, Fe fertilization critically relies on the dynamic interaction of changes in dust-Fe sources in Central South America with the circumpolar westerly wind system.

scholarly journals The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones

2010 ◽  
Vol 7 (4) ◽  
pp. 5649-5674 ◽  
Author(s):  
N. Cassar ◽  
P. J. DiFiore ◽  
B. A. Barnett ◽  
M. L. Bender ◽  
A. R. Bowie ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Primary Productivity ◽  
Light Availability ◽  
Austral Summer ◽  
Carbon Export ◽  
Net Community Production ◽  
Independent Evidence ◽  
Frontal Zones ◽  
Mixed Layers ◽  
Community Production

Abstract. The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP) and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ) and the northern reaches of the Polar Frontal Zone (PFZ), we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense) study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. Both gross primary productivity (estimated from the oxygen triple isotope anomaly) and NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m), dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.

Use of Ornamental Trees in Dating of Abandoned Cemeteries on the Example of Thuja Occidentalis and Thuja Orientalis

2012 ◽  
Vol 1 (1) ◽  
pp. 45-50
Author(s):  
Magdalena Opała ◽  
Leszek Majgier
Keyword(s):  
Climatic Conditions ◽  
The Other ◽  
Lake District ◽  
Thuja Occidentalis ◽  
North Eastern ◽  
The 1960S ◽  
Thuja Orientalis ◽  
Ornamental Trees ◽  
Common Tree ◽  
Local Habitat

Abstract Due to the lack of maintenance, abandoned cemeteries are often incorporated into the landscape. In many cases the information about the age of the cemetery is unavailable. To find out the approximate time of the formation of the cemetery the information recorded in the annual tree and shrub rings can be used. One of the most common tree species, planted for ornamental and symbolic purposes on the cemeteries, are Thuja orientalis and Thuja occidentalis. Alien to the Polish flora, these species adapted well to the local habitat and climatic conditions. The paper presents an attempt to apply dendrochronological dating to determine the age of the abandoned cemeteries in the region of the Great Masurian Lakes, part of the Masurian Lake District (north-eastern Poland). The study included five abandoned cemeteries. In total, 15 cores were taken from the trees. After applying the standard dendrochronological method, local chronologies for the studied species were established. The research indicated that the oldest found specimens - over 70 yrs old - are Thuja occidentalis individuals growing at the Słabowo cemetery. At the other sites the specimens of both Thuja species date back to the 1960s and early 1970s. Compared to the historical information regarding the age and origin of the studied objects, thujas growing there are much younger than the age of the cemeteries foundation. The presented method proved to be very helpful in understanding the time of Thuja occidentalis and Thuja orientalis introduction at the investigated cemeteries.

Pengaruh Luka Iris Pada Tikus Dengan Paparan Hidrogen Peroxida 3% terhadap Epitelisasi dan Pembentukan Eksudat pada Permukaan Epitel Kulit.

2020 ◽  
Vol 17 (2) ◽  
pp. 172
Author(s):  
HARMAN AGUSAPUTRA ◽  
MARIA SUGENG ◽  
AYLY SOEKAMTO ◽  
ATIK WULANDARI
Keyword(s):  
Hydrogen Peroxide ◽  
Wound Healing ◽  
The Other ◽  
Delayed Wound Healing ◽  
Peroxide Group ◽  
Hemostatic Effect ◽  
Significant Difference ◽  
Negative Effect ◽  
Wound Healing Effect ◽  
Epithelial Growth

<p><strong>Abstract</strong></p><p><strong>Background:</strong> Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) as antiseptic has been used frequently to clean woundsin in hospitals and clinics. Hydrogen peroxide has the effectof strong oxidative that can kill pathogens. It can clean up debris and necrotic tissuesin wounds. Hydrogen peroxidealso has hemostatic effect that can help to stop bleeding. Besides antiseptic effects, hydrogen peroxide i s suspected of having negative effect in wound healing. Hydrogen peroxide presumably could cause delayed wound healing by exudate formation and delayed epithelial growth.</p><p><strong>Method</strong>: This study was conducted in the laboratory using 48 white mice that were divided into 2 groups. All the mice were purposely wounded. Afterwards in one group the wounds were clean up using hydrogen peroxide, while in the other group without hydrogen peroxide as control. The wounds of both groups were observed on day 1, day 3 and day 7. On day 1 and day 3, both groups did not show significant difference.</p><p><strong>R</strong><strong>esult</strong> : on day 7 showed that the wound healing in hydrogen peroxide group were delayed. Fifty percent of them had the formation of exudate and 62.5% of them showed delayed epithelial growth.</p><p><strong>Conclusion </strong>: This study could show hydrogen peroxide as wound antiseptic has delayed wound healing effect.</p><p><strong>Keyword</strong>: hydrogen peroxide, wound healing</p>

Carbon export associated with free-drifting icebergs in the Southern Ocean

2011 ◽  
Vol 58 (11-12) ◽  
pp. 1485-1496 ◽  
Author(s):  
K.L. Smith ◽  
A.D. Sherman ◽  
T.J. Shaw ◽  
A.E. Murray ◽  
M. Vernet ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Carbon Export

The Value of Information in the Hold-Up Problem

2004 ◽  
Vol 5 (2) ◽  
pp. 177-203 ◽  
Author(s):  
Thomas Pfeiffer
Keyword(s):  
Information System ◽  
Information Structure ◽  
Value Of Information ◽  
The Other ◽  
Information Control ◽  
Ceteris Paribus ◽  
Head Office ◽  
Specific Investments ◽  
Negative Effect ◽  
Central Management

Abstract In the literature, the information structure of the hold-up problem is typically assumed to be exogenous. In this paper, we introduce an additional stage at which the head office may grant individual divisions access to an information system before they undertake their specific investments. Although more information ceteris paribus enhances each divisions’ profits, more information can reduce divisions’ investments and destroy synergies for the other division that would have been generated by the investments. If this negative effect dominates, then information can be harmful for the entire company. Hence, information control can be a subtle force to deal with the hold-up problem to a certain extent. In this paper we analyze those conditions under which information is either harmful or beneficial for central management.

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

Treatment of frostbite in an open way (without dressings)

1937 ◽  
Vol 33 (1) ◽  
pp. 84-86
Author(s):  
V. A. Petrovykh
Keyword(s):  
Recovery Period ◽  
Climatic Conditions ◽  
The Other ◽  
Critical Approach ◽  
Tatar Strait ◽  
Other Hand ◽  
Number Of Patients ◽  
The One ◽  
Apparent Similarity ◽  
Methods Of Treatment

The harsh climatic conditions of the coast of the Tatar Strait make explainable the large number of patients with frostbite who passed under our supervision during the winter of 1935-36 and amounted to 2.8% (26 people) of the total contingent of inpatients. The variety of recommended methods for treating frostbite, on the one hand, and the relatively long recovery period for all of them, on the other hand, made us take a critical approach to the proposed methods of treatment. All currently existing methods are reduced to the treatment of frostbite areas with bandages; and on the locus morbi apply indifferent or slightly disinfecting ointments, or a similar property of a powder, or wipes moistened with slightly disinfecting solutions, for example, Sol. kalii hyperm. 1: 1000. The apparent similarity of the external manifestations of frostbite and burns inspired us with the idea of ​​conducting frostbite therapy in an "open way", which has long occupied a well-deserved place in the treatment of burns.

scholarly journals Sea-ice induced growth decline in Arctic shrubs

2017 ◽  
Vol 13 (8) ◽  
pp. 20170122 ◽  
Author(s):  
Mads Forchhammer
Keyword(s):  
Sea Ice ◽  
Ring Width ◽  
Plant Productivity ◽  
Climatic Conditions ◽  
Arctic Sea Ice ◽  
Annual Growth ◽  
The Arctic ◽  
Growth Time ◽  
Sea Ice Extent ◽  
Negative Effect

Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-ice. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-ice and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to Svalbard, an overall negative effect of the retreating June sea-ice extent was found on the annual growth. The negative effect of the retreating June sea-ice was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth.

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