scholarly journals Changes of lake organic carbon sinks from closed basins since the Last Glacial Maximum and quantitative evaluation of human impacts

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yu Li ◽  
Xinzhong Zhang ◽  
Lingmei Xu ◽  
Yuxin Zhang ◽  
Wangting Ye ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Carbon Storage ◽  
Human Impacts ◽  
Carbon Sinks ◽  
Closed Basin ◽  
The Past ◽  
Closed Basins ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Background Closed basins occupy 21% of the world’s land area and can substantially affect global carbon budgets. Conventional understanding suggests that the terminal areas of closed basins collect water and carbon from throughout the entire basin, and changes in lake organic carbon sinks are indicative of basin-wide organic carbon storages. However, this hypothesis lacks regional and global validation. Here, we first validate the depositional process of organic carbon in a typical closed-basin region of northwest China using organic geochemical proxies of both soil and lake sediments. Then we estimate the organic carbon sinks and human impacts in extant closed-basin lakes since the Last Glacial Maximum (LGM). Results Results show that 80.56 Pg organic carbon is stored in extant closed-basin lakes mainly found in the northern mid-latitudes. Carbon accumulation rates vary from 17.54 g C m−2 yr−1 during modern times, 6.36 g C m−2 yr−1 during the mid-Holocene and 2.25 g C m−2 yr−1 during the LGM. Then, we evaluated the influence by human activities during the late Holocene (in the past three thousand years). The ratio of human impacts on lake organic carbon storage in above closed basins is estimated to be 22.79%, and human-induced soil organic carbon emissions in the past three thousand years amounted to 207 Pg. Conclusions While the magnitude of carbon storage is not comparable to those in peatland, vegetation and soil, lake organic carbon sinks from closed basins are significant to long-term terrestrial carbon budget and contain information of climate change and human impact from the whole basins. These observations improve our understanding of carbon sinks in closed basins at various time scales, and provide a basis for the future mitigation policies to global climate change.

scholarly journals Synergy of the westerly winds and monsoons in the lake evolution of global closed basins since the Last Glacial Maximum and implications for hydrological change in central Asia

2020 ◽  
Vol 16 (6) ◽  
pp. 2239-2254
Author(s):  
Yu Li ◽  
Yuxin Zhang
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Late Holocene ◽  
Westerly Winds ◽  
Low Latitudes ◽  
Closed Basins ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. The monsoon system and westerly circulation, to which climate change responds differently, are two important components of global atmospheric circulation interacting with each other in the middle to low latitudes. Relevant research on global millennial-scale climate change in monsoon and westerly regions is mostly devoted to multi-proxy analyses of lakes, stalagmites, ice cores, and marine and eolian sediments. Different responses from these proxies to long-term environmental change make understanding climate change patterns in monsoon and westerly regions difficult. Accordingly, we disaggregated global closed basins into areas governed by monsoon and westerly winds, unified paleoclimate indicators, and added lake models and paleoclimate simulations to emphatically track millennial-scale evolution characteristics and mechanisms of East Asian summer monsoon and westerly winds since the Last Glacial Maximum (LGM). Our results reveal that millennial-scale water balance change exhibits an obvious boundary between global monsoon and westerly regions in closed basins, particularly in the Northern Hemisphere. The effective moisture in most closed basins of the midlatitude Northern Hemisphere mainly exhibits a decreasing trend since the LGM, while that of the low latitudes shows an increasing trend. In the monsoon-dominated closed basins of Asia, a humid climate prevails in the early to mid-Holocene, and a relatively dry climate appears in the LGM and late Holocene. In the westerly-wind-dominated closed basins of Asia, the climate is characterized by a humid LGM and mid-Holocene (MH) compared with the dry early and late Holocene, which is likely to be connected to precipitation brought by the westerly circulation. This study provides insight into the long-term evolution and synergy of westerly winds and monsoon systems as well as a basis for the projection of future hydrological balance.

scholarly journals Synergy of the westerly winds and monsoons in lake evolution of global closed basins since the Last Glacial Maximum

2020 ◽  
Author(s):  
Yu Li ◽  
Yuxin Zhang
Keyword(s):  
Climate Change ◽  
Last Glacial Maximum ◽  
Northern Hemisphere ◽  
Westerly Winds ◽  
Low Latitudes ◽  
Closed Basins ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. Monsoon system and westerly circulation, to which climate change responds differently, are two important components of global atmospheric circulation, interacting with each other in the mid-to-low latitudes and having synergy effect to those regions. Relevant researches on global millennial-scale climate change in monsoon and westerlies regions are mostly devoted to multi-proxy analyses of lakes, stalagmites, ice cores, marine and eolian sediments. Different responses from these proxies to long-term environmental change make understanding climate change pattern in monsoonal and westerlies regions difficult. Accordingly, we disaggregated global closed basins into areas governed by monsoon and westerly winds and unified palaeoclimate indicators, as well as combined with the lake models and paleoclimate simulations for tracking millennial-scale evolution characteristics and mechanisms of global monsoon and westerly winds since the Last Glacial Maximum (LGM). Our results concluded that the effective moisture in most closed basins of the mid-latitudes Northern Hemisphere is mainly a trend on the decrease since the LGM, and of the low-latitudes is mainly a trend on the rise. Millennial-scale water balance change exhibits an obvious boundary between global westerlies and monsoon regions in closed basins, particularly in the Northern Hemisphere. In the monsoon dominated closed basins of the Northern Hemisphere, humid climate prevails in the early-mid Holocene and relative dry climate appears in the LGM and late Holocene. While in the westerly winds dominated closed basins of the Northern Hemisphere, climate is characterized by relative humid LGM and mid-Holocene (MH) compared with the dry early Holocene, which is likely to be connected with precipitation brought by the westerly circulation. This study provides insights into long-term evolution and synergy of monsoon and westerly wind systems and basis for projection of future hydrological balance in the low-to-mid latitudes.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

scholarly journals An Orchid in Retrograde: Climate-Driven Range Shift Patterns of Ophrys helenae in Greece

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 470
Author(s):  
Martha Charitonidou ◽  
Konstantinos Kougioumoutzis ◽  
John M. Halley
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Species Distribution Modelling ◽  
Range Shift ◽  
Last Interglacial ◽  
Distribution Modelling ◽  
Species Response ◽  
Northwestern Greece ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Climate change is regarded as one of the most important threats to plants. Already species around the globe are showing considerable latitudinal and altitudinal shifts. Helen’s bee orchid (Ophrys helenae), a Balkan endemic with a distribution center in northwestern Greece, is reported to be expanding east and southwards. Since this southeastern movement goes against the usual expectations, we investigated via Species Distribution Modelling, whether this pattern is consistent with projections based on the species’ response to climate change. We predicted the species’ future distribution based on three different climate models in two climate scenarios. We also explored the species’ potential distribution during the Last Interglacial and the Last Glacial Maximum. O. helenae is projected to shift mainly southeast and experience considerable area changes. The species is expected to become extinct in the core of its current distribution, but to establish a strong presence in the mid- and high-altitude areas of the Central Peloponnese, a region that could have provided shelter in previous climatic extremes.

Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest

2021 ◽  
pp. 1-11
Author(s):  
Jason A. Rech ◽  
Jeffrey S. Pigati ◽  
Kathleen B. Springer ◽  
Stephanie Bosch ◽  
Jeffrey C. Nekola ◽  
...  
Keyword(s):  
Climate Change ◽  
Oxygen Isotopic Composition ◽  
American Southwest ◽  
Quaternary Climate ◽  
San Pedro ◽  
Spatial Coverage ◽  
Oxygen Isotopic ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Terrestrial Gastropod

Abstract Recent studies have shown the oxygen isotopic composition (δ18O) of modern terrestrial gastropod shells is determined largely by the δ18O of precipitation. This implies that fossil shells could be used to reconstruct the δ18O of paleo-precipitation as long as the isotopic system, including the hydrologic pathways of the local watershed and the gastropod systematics, is well understood. In this study, we measured the δ18O values of 456 individual gastropod shells collected from paleowetland deposits in the San Pedro Valley, Arizona that range in age from ca. 29.1 to 9.8 ka. Isotopic differences of up to 2‰ were identified among the four taxa analyzed (Succineidae, Pupilla hebes, Gastrocopta tappaniana, and Vallonia gracilicosta), with Succineidae shells yielding the highest values and V. gracilicosta shells exhibiting the lowest values. We used these data to construct a composite isotopic record that incorporates these taxonomic offsets, and found shell δ18O values increased by ~4‰ between the last glacial maximum and early Holocene, which is similar to the magnitude, direction, and rate of isotopic change recorded by speleothems in the region. These results suggest the terrestrial gastropods analyzed here may be used as a proxy for past climate in a manner that is complementary to speleothems, but potentially with much greater spatial coverage.

Soil organic carbon storage by shaded and unshaded coffee systems and its implications for climate change mitigation in China

2021 ◽  
pp. 1-8
Author(s):  
Ziwei Xiao ◽  
Xuehui Bai ◽  
Mingzhu Zhao ◽  
Kai Luo ◽  
Hua Zhou ◽  
...  
Keyword(s):  
Climate Change ◽  
Linear Regression ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Multiple Linear Regression ◽  
Carbon Storage ◽  
Soil Ph ◽  
Soil Bulk Density ◽  
Soil N ◽  
And Storage

Abstract Shaded coffee systems can mitigate climate change by fixation of atmospheric carbon dioxide (CO2) in soil. Understanding soil organic carbon (SOC) storage and the factors influencing SOC in coffee plantations are necessary for the development of sound land management practices to prevent land degradation and minimize SOC losses. This study was conducted in the main coffee-growing regions of Yunnan; SOC concentrations and storage of shaded and unshaded coffee systems were assessed in the top 40 cm of soil. Relationships between SOC concentration and factors affecting SOC were analysed using multiple linear regression based on the forward and backward stepwise regression method. Factors analysed were soil bulk density (ρb), soil pH, total nitrogen of soil (N), mean annual temperature (MAT), mean annual moisture (MAM), mean annual precipitation (MAP) and elevations (E). Akaike's information criterion (AIC), coefficient of determination (R2), root mean square error (RMSE) and residual sum of squares (RSS) were used to describe the accuracy of multiple linear regression models. Results showed that mean SOC concentration and storage decreased significantly with depth under unshaded coffee systems. Mean SOC concentration and storage were higher in shaded than unshaded coffee systems at 20–40 cm depth. The correlations between SOC concentration and ρb, pH and N were significant. Evidence from the multiple linear regression model showed that soil bulk density (ρb), soil pH, total nitrogen of soil (N) and climatic variables had the greatest impact on soil carbon storage in the coffee system.

scholarly journals Mitochondrial Genome Diversity in the Central Siberian Plateau with Particular Reference to Prehistory of Northernmost Eurasia

2019 ◽  
Author(s):  
S. V. Dryomov ◽  
A. M. Nazhmidenova ◽  
E. B. Starikovskaya ◽  
S. A. Shalaurova ◽  
N. Rohland ◽  
...  
Keyword(s):  
Geographic Area ◽  
Mtdna Sequences ◽  
The Past ◽  
South Central ◽  
Sayan Region ◽  
History Of ◽  
Mitochondrial Genome Diversity ◽  
The Last Glacial Maximum ◽  
Complete Mtdna ◽  
The Last Glacial

AbstractThe Central Siberian Plateau was last geographic area in Eurasia to become habitable by modern humans after the Last Glacial Maximum (LGM). Through comprehensive mitochondrial DNA genomes retained in indigenous Siberian populations, the Ket, Tofalar, and Todzhi - we explored genetic links between the Yenisei-Sayan region and Northeast Eurasia over the last 10,000 years. Accordingly, we generated 218 new complete mtDNA sequences and placed them into compound phylogenies along with 7 newly obtained and 70 published ancient mt genomes. Our findings reflect the origins and expansion history of mtDNA lineages that evolved in South-Central Siberia, as well as multiple phases of connections between this region and distant parts of Eurasia. Our result illustrates the importance of jointly sampling modern and prehistoric specimens to fully measure the past genetic diversity and to reconstruct the process of peopling of the high latitudes of the Siberian subcontinent.

scholarly journals Carbon storage along altitudes in agrisilviculture system- Case study of Devprayag Block, Tehri District, Uttarakhand, India

2020 ◽  
Vol 7 (9) ◽  
pp. 29-38
Author(s):  
K.K. Vikrant ◽  
D.S. Chauhan ◽  
R.H. Rizvi
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Storage ◽  
Carbon Stock ◽  
Total Carbon ◽  
Total Biomass ◽  
Biomass Carbon ◽  
Total Carbon Stock ◽  
Crop Biomass

Climate change is one of the impending problems that have affected the productivity of agroecosystems which calls for urgent action. Carbon sequestration through agroforestry along altitude in mountainous regions is one of the options to contribute to global climate change mitigation. Three altitudes viz. lower (286-1200m), middle (1200-2000m), and upper (2000-2800m) have been selected in Tehri district. Ten Quadrates (10m × 10 m) were randomly selected from each altitude in agrisilviculture system. At every sampling point, one composite soil sample was taken at 30 cm soil depth for soil organic carbon analysis. For the purpose of woody biomass, Non destructive method and for crop biomass assessment destructive method was employed. Finally, aboveground biomass (AGB), belowground biomass carbon (BGB), Total tree Biomass (TTB), Crop biomass (CB), Total Biomass (TB), Total biomass carbon (TBC), soil organic carbon (SOC), and total carbon stock (TC) status were estimated and variables were compared using one-way analysis of variance (ANOVA).The result indicated that AGB, BGB, TTB, CB , TB, TBC, SOC, and TC varied significantly (p < 0.05) across the altitudes. Results showed that total carbon stock followed the order upper altitude ˃ middle altitudes ˃ lower altitude. The upper altitude (2000-2800 m) AGB, BGB,TTB, TBC,SOC, and TC stock was estimated as 2.11 Mg ha-1 , 0.52 Mg ha-1, 2.63 Mg ha-1, 2.633 Mg ha-1, 1.18 Mg ha-1 , 26.53 Mg ha-1, 38.48 Mg ha-1 respectively, and significantly higher than the other altitudes. It was concluded that agrisilviculture system hold a high potential for carbon storage at temperate zones. Quercus lucotrichophora, Grewia oppositifolia and Melia azadirach contributed maximum carbon storage which may greatly contribute to the climate resilient green economy strategy and their conservation should be promoted.

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