scholarly journals Patterns of terrestrial plant carbon: late Mesozoic and Cenozoic

1992 ◽  
Vol 6 ◽  
pp. 225-225
Author(s):  
Jerry Olson ◽  
Garland R. Upchurch
Keyword(s):  
Global Scale ◽  
Late Eocene ◽  
Early Miocene ◽  
Strongly Correlated ◽  
Carbon Density ◽  
Terrestrial Plant ◽  
Late Mesozoic ◽  
Major Increase ◽  
Temperate Rainforests ◽  
Global Carbon

Variation in terrestrial productivity and biomass impacts evolution through linkages between productivity and biodiversity and through the types of resources available for consumption by herbivores. Geographic variation in terrestrial plant carbon is known on a global scale for extant biomes and is strongly correlated with precipitation, temperature, and the area of wetlands. Although estimates of extant terrestrial plant carbon density are still somewhat uncertain, the highest densities clearly occur in tropical and temperate rainforests, and the lowest occur in deserts, semideserts, and arctic/alpine tundra. Patterns of variation in ancient terrestrial plant carbon can be estimated through the correlation between biome/climate and carbon density, provided individual biomes show little change through time in primary productivity or density of plant carbon.Density of terrestrial plant carbon has been estimated on a global scale for the latest Cretaceous, late Paleocene/Eocene, middle-late Eocene, early Miocene, and Holocene/Recent using the biomal reconstructions of Wolfe (1984), Upchurch (this symposium), and others. Latest Cretaceous (Maastrichtian) estimates indicate a relatively low value of 700-800 gigatons, which may underestimate carbon due to the presence of extensive latest Cretaceous coastal wetlands. However, much of this figure is readliy explainable by extensive deserts in Asia and little evidence for areally extensive tropical rainforest.Major increase in terrestrial plant carbon occurred during the Paleocene/earliest Eocene in conjunction with a major areal increase in rainforest. During the early Miocene terrestrial global carbon was approximately 1200-1300 gigatons. This figure decreased by about half between the early Miocene and Holocene/Recent. The decrease in terrestrial carbon density resulted from a decrease in area of tropical and subtropical forests and increase in area of deserts, grasslands, and mediterranean woodlands/chapparal.

scholarly journals Late Eocene to early Miocene ice sheet dynamics and the global carbon cycle

2004 ◽  
Vol 19 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. H. Lear ◽  
Y. Rosenthal ◽  
H. K. Coxall ◽  
P. A. Wilson
Keyword(s):  
Carbon Cycle ◽  
Ice Sheet ◽  
Global Carbon Cycle ◽  
Late Eocene ◽  
Early Miocene ◽  
Ice Sheet Dynamics ◽  
Global Carbon

scholarly journals Evaluation of modeled global carbon dynamics: analysis based on global carbon flux and above-ground biomass data

2016 ◽  
Author(s):  
Bao-Lin Xue ◽  
Qinghua Guo ◽  
Tianyu Hu ◽  
Yongcai Wang ◽  
Shengli Tao ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Carbon Flux ◽  
Large Scale ◽  
Gross Primary Production ◽  
Carbon Dynamics ◽  
Global Scale ◽  
Above Ground Biomass ◽  
Carbon Cycles ◽  
Ground Biomass ◽  
Global Carbon

Abstract. Dynamic global vegetation models are useful tools for the simulation of carbon dynamics on regional and global scales. However, even the most validated models are usually hampered by the poor availability of global biomass data in the model validation, especially on regional/global scales. Here, taking the integrated biosphere simulator model (IBIS) as an example, we evaluated the modeled carbon dynamics, including gross primary production (GPP) and potential above-ground biomass (AGB), on the global scale. The IBIS model was constrained by both in situ GPP and plot-level AGB data collected from the literature. Independent validation showed that IBIS could reproduce GPP and evapotranspiration with acceptable accuracy at site and global levels. On the global scale, the IBIS-simulated total AGB was similar to those obtained in other studies. However, discrepancies were observed between the model-derived and observed spatial patterns of AGB for Amazonian forests. The differences among the AGB spatial patterns were mainly caused by the single-parameter set of the model used. This study showed that different meteorological inputs can also introduce substantial differences in AGB on the global scale. Further analysis showed that this difference is small compared with parameter-induced differences. The conclusions of our research highlight the necessity of considering the heterogeneity of key model physiological parameters in modeling global AGB. The research also shows that to simulate large-scale carbon dynamics, both carbon flux and AGB data are necessary to constrain the model. The main conclusions of our research will help to improve model simulations of global carbon cycles.

scholarly journals The Late Eocene-Early Miocene Unconformities of the NW Indian Intraplate Basins and Himalayan Foreland: A Record of Tectonics or Mantle Dynamics?

Tectonics ◽  
2018 ◽  
Vol 37 (10) ◽  
pp. 3970-3985 ◽  
Author(s):  
Yani Najman ◽  
Stuart D. Burley ◽  
Alex Copley ◽  
Michael J. Kelly ◽  
Kaushal Pander ◽  
...  
Keyword(s):  
Late Eocene ◽  
Early Miocene ◽  
Mantle Dynamics

Synchronous Eocene deformation recorded on either side of a major Miocene thrust bounding the Almyropotamos tectonic window in Evia, Greece

2021 ◽  
Author(s):  
Taylor Ducharme ◽  
Iwona Klonowska ◽  
David Schneider ◽  
Bernhard Grasemann ◽  
Kostantinos Soukis
Keyword(s):  
Regional Scale ◽  
Late Eocene ◽  
White Mica ◽  
Early Miocene ◽  
Lower Grade ◽  
Metamorphic History ◽  
Tectonic Window ◽  
Platform Carbonates ◽  
C 30 ◽  
Type 3

<p>Southern Evia in Greece exposes an inverted high pressure-low temperature (HP-LT) metamorphic sequence that has been loosely correlated with the Cycladic Blueschist Unit (CBU). On the island, the CBU is divided into the metavolcanic and ophiolitic Ochi Nappe and predominantly metacarbonate Styra Nappe. A lower-grade unit, the Almyropotamos Nappe, is exposed in the core of a N-S trending antiform and comprises Eocene platform carbonates overlain by metaflysch. The Almyropotamos Nappe occupies a tectonic window defined by the Evia Thrust, a brittle-ductile fault zone that emplaced the Ochi and Styra nappes atop the Almyropotamos Nappe. New multiple single-grain white mica total fusion <sup>40</sup>Ar/<sup>39</sup>Ar ages indicate that deformation occurred along the Evia Thrust at 25-23 Ma. White mica <sup>40</sup>Ar/<sup>39</sup>Ar data on either side of the tectonic window record Eocene dates between 40 and 32 Ma, consistent with previously published <sup>40</sup>Ar/<sup>39</sup>Ar dates and a single Rb-Sr age of c. 30 Ma. These ages broadly coincide with estimates for the timing of NE-directed thrusting of the Ochi Nappe over the Styra Nappe. Strain associated with thrusting localized as cylindrical folds in Styra marbles, with fold axes parallel to the stretching lineation and a clear strain gradient increasing toward the upper contact with the Ochi Nappe. The most prominent structures in the Ochi Nappe are a strong L-S fabric defined by acicular blue amphibole and type-3 refold structures with fold axes trending parallel to the NE-SW oriented stretching lineation. Whereas the Ochi Nappe and Styra Nappe locally preserve peak blueschist facies mineral assemblages, all three units commonly display evidence only for retrogressed initial HP-LT assemblages in the form of ferroglaucophane inclusions in albite porphyroblasts. Isochemical phase diagrams calculated in the Na<sub>2</sub>O-CaO-K<sub>2</sub>O-FeO-MgO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-H<sub>2</sub>O-TiO<sub>2</sub>±O<sub>2</sub> system support minimum peak metamorphic conditions of 12.5 ± 1.5 kbar and 465 ± 75 °C for an Ochi Nappe blueschist, and 6.0 ± 0.5 kbar and 315 ± 15 °C for an albite mica schist from the Evia Thrust. Peak P-T conditions for the Ochi Nappe support a metamorphic history more closely resembling that of the Lower Cycladic Blueschist Nappe, indicating that the entire section of the CBU exposed on Evia lies below the Trans-Cycladic Thrust. The Early Miocene ages from the Evia Thrust overlap with the proposed timing for the initiation of bivergent greenschist facies extension in the Cyclades. The remainder of the region, including high-strain corridors within individual nappes such as the Almyropotamos Thrust, uniformly records Eocene deformation ages. The similarity in <sup>40</sup>Ar/<sup>39</sup>Ar ages across the tectonic window contrasts with age relationships observed in similar tectonic packages on Lavrion, and suggests that regional scale deformation persisted until the Late Eocene before strain became localized in brittle-ductile corridors by the Early Miocene. </p>

scholarly journals Global signal of top-down control of terrestrial plant communities by herbivores

2018 ◽  
Vol 115 (24) ◽  
pp. 6237-6242 ◽  
Author(s):  
Shihong Jia ◽  
Xugao Wang ◽  
Zuoqiang Yuan ◽  
Fei Lin ◽  
Ji Ye ◽  
...  
Keyword(s):  
Plant Communities ◽  
Meta Analysis ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
Basic Site ◽  
Plant Interactions ◽  
Top Down ◽  
Plant Abundance ◽  
Terrestrial Plant ◽  
Positive Effects

The theory of “top-down” ecological regulation predicts that herbivory suppresses plant abundance, biomass, and survival but increases diversity through the disproportionate consumption of dominant species, which inhibits competitive exclusion. To date, these outcomes have been clear in aquatic ecosystems but not on land. We explicate this discrepancy using a meta-analysis of experimental results from 123 native animal exclusions in natural terrestrial ecosystems (623 pairwise comparisons). Consistent with top-down predictions, we found that herbivores significantly reduced plant abundance, biomass, survival, and reproduction (allP< 0.01) and increased species evenness but not richness (P= 0.06 andP= 0.59, respectively). However, when examining patterns in the strength of top-down effects, with few exceptions, we were unable to detect significantly different effect sizes among biomes, based on local site characteristics (climate or productivity) or study characteristics (study duration or exclosure size). The positive effects on diversity were only significant in studies excluding large animals or located in temperate grasslands. The results demonstrate that top-down regulation by herbivores is a pervasive process shaping terrestrial plant communities at the global scale, but its strength is highly site specific and not predicted by basic site conditions. We suggest that including herbivore densities as a covariate in future exclosure studies will facilitate the discovery of unresolved macroecology trends in the strength of herbivore–plant interactions.

scholarly journals Evaluation of spatial-temporal variation performance of ERA5 precipitation data in China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Donglai Jiao ◽  
Nannan Xu ◽  
Fan Yang ◽  
Ke Xu
Keyword(s):  
Observational Data ◽  
Correlation Coefficient ◽  
Global Scale ◽  
Precipitation Trend ◽  
Strongly Correlated ◽  
Precipitation Data ◽  
Weather Forecasts ◽  
Fifth Generation ◽  
Data Assessment ◽  
Long Time

AbstractERA5 is the latest fifth-generation reanalysis global atmosphere dataset from the European Centre for Medium-Range Weather Forecasts, replacing ERA-Interim as the next generation of representative satellite-observational data on the global scale. ERA5 data have been evaluated and applied in different regions, but the performances are inconsistent. Meanwhile, there are few precise evaluations of ERA5 precipitation data over long time series have been performed in Chinese mainland. This study evaluates the temporal-spatial performance of ERA5 precipitation data from 1979 to 2018 based on gridded-ground meteorological station observational data across China. The results showed that ERA5 data could capture the annual and seasonal patterns of observed precipitation in China well, with correlation coefficient values ranging from 0.796 to 0.945, but ERA5 slightly overestimated precipitation in the summer. Nonetheless, the results also showed that the accuracy of the precipitation products was strongly correlated with topographic distribution and climatic divisions. The performance of ERA5 shows spatial inherently across China that the highest correlation coefficient values locate in eastern, Northwestern and North China and the lowest biases locate in Southeast China. This study provides a reliable data assessment of the ERA5 data and precipitation trend analyses in China. The results provide accuracy references for the further use of precipitation satellite data for hydrological calculations and climate numerical simulations.

Peonza: new gastropod genus from the middle Tertiary of Patagonia and Chile

1994 ◽  
Vol 68 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Amalia M. Olivera ◽  
William J. Zinsmeister ◽  
S. Graciela Parma
Keyword(s):  
New Species ◽  
Temporal Distribution ◽  
Late Eocene ◽  
Tierra Del Fuego ◽  
Early Miocene ◽  
Late Oligocene ◽  
Southern Chile ◽  
Santa Cruz ◽  
Two New Species

A new Tertiary gastropod genus, Peonza n. gen., is described, along with two new species, P. torquata from southern Argentina and P. benjamina from southern Chile. These muricacean gastropods, of uncertain familial status, occur in the late Eocene San Julián Formation and in the late Oligocene to early Miocene? Monte León Formation, Santa Cruz Province, Argentina. They also were recorded in the (probably) Oligocene Magellanian beds in Tierra del Fuego, Argentina, and in early Miocene deposits of the Tres Montes region in the Chilean Canals. In spite of the small number of specimens, Peonza n. gen. seems to have had a wide geographic and temporal distribution.

scholarly journals Controls over aboveground forest carbon density on Barro Colorado Island, Panama

2011 ◽  
Vol 8 (6) ◽  
pp. 1615-1629 ◽  
Author(s):  
J. Mascaro ◽  
G. P. Asner ◽  
H. C. Muller-Landau ◽  
M. van Breugel ◽  
J. Hall ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Tropical Forests ◽  
Slope Angle ◽  
Global Carbon Cycle ◽  
Barro Colorado Island ◽  
Satellite Monitoring ◽  
Secondary Forests ◽  
Carbon Density ◽  
Site Factors ◽  
Global Carbon

Abstract. Despite the importance of tropical forests to the global carbon cycle, ecological controls over landscape-level variation in live aboveground carbon density (ACD) in tropical forests are poorly understood. Here, we conducted a spatially comprehensive analysis of ACD variation for a continental tropical forest – Barro Colorado Island, Panama (BCI) – and tested site factors that may control such variation. We mapped ACD over 1256 ha of BCI using airborne Light Detection and Ranging (LiDAR), which was well-correlated with ground-based measurements of ACD in Panamanian forests of various ages (r2 = 0.84, RMSE = 17 Mg C ha−1, P < 0.0001). We used multiple regression to examine controls over LiDAR-derived ACD, including slope angle, forest age, bedrock, and soil texture. Collectively, these variables explained 14 % of the variation in ACD at 30-m resolution, and explained 33 % at 100-m resolution. At all resolutions, slope (linked to underlying bedrock variation) was the strongest driving factor; standing carbon stocks were generally higher on steeper slopes. This result suggests that physiography may be more important in controlling ACD variation in Neotropical forests than currently thought. Although BCI has been largely undisturbed by humans for a century, past land-use over approximately half of the island still influences ACD variation, with younger forests (80–130 years old) averaging ~15 % less carbon storage than old-growth forests (>400 years old). If other regions of relatively old tropical secondary forests also store less carbon aboveground than primary forests, the effects on the global carbon cycle could be substantial and difficult to detect with traditional satellite monitoring.

Where are the proto-South China Sea slabs? SE Asia plate tectonic and mantle flow insights from TERRA global mantle convection models

2020 ◽  
Author(s):  
Yi-An Lin ◽  
Lorenzo Colli ◽  
Jonny Wu
Keyword(s):  
South China Sea ◽  
South China ◽  
Late Eocene ◽  
Early Miocene ◽  
Philippine Sea Plate ◽  
Plate Tectonic ◽  
China Sea ◽  
Se Asia ◽  
Plate Models ◽  
Geodynamic Models

&lt;p&gt;In this study we explored the contrasted plate tectonic reconstructions proposed for the proto-South China Sea and SE Asia. We implemented four different end-member plate models into global geodynamic models to test their predicted mantle structure against tomography. All models reproduced the Sunda slabs beneath Peninsular Malaysia, Sumatra and Java and the proto-South China Sea (PSCS) slabs beneath present Palawan, northern Borneo, and offshore Palawan; some models also predicted slabs under the southern South China Sea. PSCS slabs generated from double-sided PSCS subduction and earlier Borneo rotation generated a slightly better fit to tomography but pure southward PSCS subduction was also viable. A smaller Philippine Sea plate (PSP) with a short ~1000 km restored northern slab (i.e. Ryukyu slab) was clearly superior to a very long &gt;3000 km slab. Mantle flows generated from our geodynamic models suggest strong upwellings under Indochina during the late Eocene to Oligocene. Our models generated strong downwellings under the South China Sea in the late Cenozoic that did not support a deep-origin &amp;#8216;Hainan plume&amp;#8217;.&amp;#160;&lt;/p&gt;&lt;p&gt;The following plate models variants were assimilated in the geodynamic models: (1) southward vs. double-sided PSCS subduction; (2) early Borneo counterclockwise rotations during the Oligocene to Early Miocene vs. later rotations (mid- to Late Eocene and Early Miocene); (3) a smaller Philippine Sea plate restored with a shorter ~1000 km northern slab vs. a longer &gt;3000 km slab. This study assimilates four different plate models into the numerical model TERRA (Bunge et al., 1998). We digitally re-built in GPlates (Boyden et al., 2011) the implemented the plate models as a set of continuously closing plates in order to generate a global self-consistent velocity field to be assimilated into the convection models. The temperature fields were converted to seismic velocities assuming a Pyrolite composition and equilibrium mineralogy. We quantify the correlation between our geodynamic models and seismic tomography within SE Asia. For the tomography models S40RTS and LLNL-G3Dv-JPS we explicitly accounted for their finite resolution (Ritsema et al., 2011; Simmons et al. 2019).&lt;/p&gt;

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