A new negative feedback mechanism for balancing Tibet uplift-driven CO2 drop: Evidence from Paleogene chemical weathering records in the northern Tibetan Plateau

2020 ◽  
Author(s):  
Xiaomin Fang ◽  
Albert Galy ◽  
Yibo Yang ◽  
Weilin Zhang ◽  
Chengcheng Ye ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Carbon Cycle ◽  
Negative Feedback ◽  
Feedback Mechanism ◽  
Global Temperature ◽  
Silicate Weathering ◽  
Negative Feedback Mechanism ◽  
Northern Tibetan Plateau ◽  
Organic Carbon Burial ◽  
Global Cooling

<p>The CO<sub>2</sub> degassing by plate tectonic process has long been thought to be balanced by weathering of silicate rocks on continents, keeping the Earth a relative stable global carbon cycle and temperature suitable for life creation, survival and evolution. The uplift of the Tibetan Plateau (TP) is hypothesized to enhance erosion and silicate weathering and organic carbon burial, thus cool the global temperature. However, the imbalance resulting from accelerated CO<sub>2</sub> consumption by uplift of the TP and a relatively stable CO<sub>2</sub> input from volcanic degassing during the Cenozoic should have depleted atmospheric CO<sub>2</sub> within a few million years; therefore, a negative feedback mechanism must have stabilised the carbon cycle. Here, we present the first almost complete Paleogene silicate weathering intensity (SWI) records from continental rocks in the northern TP, based on detailed volcanic ash and paleomagnetic dating of two continuous Cenozoic sections in the Xining and Qaidam Basin in NW China. They show that the Paleogene silicate weathering in this tectonically inactive area was modulated by global temperature. These findings suggest that Paleogene global cooling was also strongly influenced by the temperature feedback mechanism that regulated silicate weathering rates and hydrological cycles and maintained a nearly stable carbon cycle. It acted as a negative feedback through decreasing CO<sub>2</sub> consumption resulting from the lower SWI and the kinetic limitations in tectonically inactive areas that followed the global cooling. This means that the enhanced erosion and silicate weathering by the uplift of the south and central Tibetan Plateau, thus accelerated CO<sub>2</sub> consumption, must be compensated by reducing CO<sub>2</sub> consumption of the rest vast continents through their reduced silicate weathering from cooling.</p>

Paleogene global cooling–induced temperature feedback on chemical weathering, as recorded in the northern Tibetan Plateau

Geology ◽  
2019 ◽  
Vol 47 (10) ◽  
pp. 992-996 ◽  
Author(s):  
Xiaomin Fang ◽  
Albert Galy ◽  
Yibo Yang ◽  
Weilin Zhang ◽  
Chengcheng Ye ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Carbon Cycle ◽  
Negative Feedback ◽  
Feedback Mechanism ◽  
Silicate Weathering ◽  
Northern Tibetan Plateau ◽  
Co2 Consumption ◽  
Temperature Feedback ◽  
Organic Carbon Burial ◽  
Global Cooling

Abstract Plate-tectonic processes have long been thought to be the major cause of the Cenozoic global carbon cycle, and global cooling by uplift of the Tibetan Plateau through enhancing silicate weathering and organic carbon burial and/or by weathering of obducted ophiolites during the closure of the Neo-Tethys Ocean. However, the imbalance resulting from accelerated CO2 consumption and a relatively stable CO2 input from volcanic degassing during the Cenozoic should have depleted atmospheric CO2 within a few million years; therefore, a negative feedback mechanism must have stabilized the carbon cycle. Here, we present the first almost-complete Paleogene silicate weathering intensity (SWI) records from continental rocks in the northern Tibetan Plateau showing that silicate weathering in this tectonically inactive area was modulated by global temperature. These findings suggest that Paleogene global cooling was also strongly influenced by a temperature feedback mechanism, which regulated silicate weathering rates and hydrological cycles and maintained a nearly stable carbon cycle. It acted as a negative feedback by decreasing CO2 consumption resulting from the lower SWI and the kinetic limitations in tectonically inactive areas.

Activation of the Na+/K+-ATPase by insulin and glucose as a putative negative feedback mechanism in pancreatic beta-cells

2008 ◽  
Vol 457 (6) ◽  
pp. 1351-1360 ◽  
Author(s):  
M. Düfer ◽  
D. Haspel ◽  
P. Krippeit-Drews ◽  
L. Aguilar-Bryan ◽  
J. Bryan ◽  
...  
Keyword(s):  
Beta Cells ◽  
Negative Feedback ◽  
Pancreatic Beta Cells ◽  
Feedback Mechanism ◽  
Negative Feedback Mechanism

scholarly journals Negative feedback in ants: crowding results in less trail pheromone deposition

2013 ◽  
Vol 10 (81) ◽  
pp. 20121009 ◽  
Author(s):  
Tomer J. Czaczkes ◽  
Christoph Grüter ◽  
Francis L. W. Ratnieks
Keyword(s):  
Negative Feedback ◽  
Trail Pheromone ◽  
Distribution Networks ◽  
Feedback Mechanism ◽  
Lasius Niger ◽  
Feedback Signal ◽  
Control Mechanisms ◽  
Negative Feedback Mechanism ◽  
Self Organized ◽  
Fold Reduction

Crowding in human transport networks reduces efficiency. Efficiency can be increased by appropriate control mechanisms, which are often imposed externally. Ant colonies also have distribution networks to feeding sites outside the nest and can experience crowding. However, ants do not have external controllers or leaders. Here, we report a self-organized negative feedback mechanism, based on local information, which downregulates the production of recruitment signals in crowded parts of a network by Lasius niger ants. We controlled crowding by manipulating trail width and the number of ants on a trail, and observed a 5.6-fold reduction in the number of ants depositing trail pheromone from least to most crowded conditions. We also simulated crowding by placing glass beads covered in nest-mate cuticular hydrocarbons on the trail. After 10 bead encounters over 20 cm, forager ants were 45 per cent less likely to deposit pheromone. The mechanism of negative feedback reported here is unusual in that it acts by downregulating the production of a positive feedback signal, rather than by direct inhibition or the production of an inhibitory signal.

scholarly journals Significant recent warming over the northern Tibetan Plateau from ice core <i>δ</i><sup>18</sup>O records

2016 ◽  
Vol 12 (2) ◽  
pp. 201-211 ◽  
Author(s):  
W. An ◽  
S. Hou ◽  
W. Zhang ◽  
Y. Wang ◽  
Y. Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ice Core ◽  
Ice Cores ◽  
Global Temperature ◽  
Temperature History ◽  
Temperature Record ◽  
Northern Tibetan Plateau ◽  
Recent Warming ◽  
Warming Hiatus ◽  
Instrumental Records

Abstract. Stable oxygen isotopic records in ice cores provide valuable information about past temperature, especially for regions with scarce instrumental measurements. This paper presents the δ18O result of an ice core drilled to bedrock from Mt. Zangser Kangri (ZK), a remote area on the northern Tibetan Plateau (TP). We reconstructed the temperature series for 1951–2008 from the δ18O records. In addition, we combined the ZK δ18O records with those from three other ice cores in the northern TP (Muztagata, Puruogangri, and Geladaindong) to reconstruct a regional temperature history for the period 1951–2002 (RTNTP). The RTNTP showed significant warming at 0.51 ± 0.07 °C (10 yr)−1 since 1970, a higher rate than the trend of instrumental records of the northern TP (0.43 ± 0.08 °C (10 yr)−1) and the global temperature trend (0.27 ± 0.03°C (10 yr)−1) at the same time. In addition, the ZK temperature record, with extra length until 2008, seems to suggest that the rapid elevation-dependent warming continued for this region during the last decade, when the mean global temperature showed very little change. This could provide insights into the behavior of the recent warming hiatus at higher elevations, where instrumental climate records are lacking.

scholarly journals RGS4 is a negative feedback mechanism of Angiotensin II‐mediated aldosterone production in human adrenal cells

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Damian G Romero ◽  
Maria W Plonczynski ◽  
Licy L Yanes ◽  
Tanganika R Washington ◽  
Gina Covington ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Negative Feedback ◽  
Feedback Mechanism ◽  
Adrenal Cells ◽  
Negative Feedback Mechanism ◽  
Aldosterone Production

Intrinsic and extrinsic mechanisms contribute to maintain the JAK/STAT pathway aberrantly activated in T-type large granular lymphocyte leukemia

Blood ◽  
2013 ◽  
Vol 121 (19) ◽  
pp. 3843-3854 ◽  
Author(s):  
Antonella Teramo ◽  
Cristina Gattazzo ◽  
Francesca Passeri ◽  
Albana Lico ◽  
Giulia Tasca ◽  
...  
Keyword(s):  
Negative Feedback ◽  
Feedback Mechanism ◽  
Large Granular Lymphocyte ◽  
Large Granular Lymphocyte Leukemia ◽  
Negative Feedback Mechanism ◽  
Key Points ◽  
Stat Pathway

Key PointsIn T-LGLL, autologous LGL-depleted PBMCs release high levels of IL-6 contributing to the constitutive STAT3 activation in leukemic LGL. Leukemic LGLs show SOCS3 down-modulation, which is responsible for lack of the negative feedback mechanism controlling STAT3 activation.

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