Long-term fluvial archives in Hungary: response of the Danube and Tisza rivers to tectonic movements and climatic changes during the Quaternary: a review and new synthesis

2007 ◽  
Vol 26 (22-24) ◽  
pp. 2758-2782 ◽  
Author(s):  
Gyula Gábris ◽  
Annamária Nádor
Keyword(s):  
Climatic Changes ◽  
New Synthesis ◽  
Fluvial Archives ◽  
Tectonic Movements

A quantitative synthesis of Holocene vegetation change in Nigeria (Western Africa)

The Holocene ◽  
2021 ◽  
pp. 095968362110331
Author(s):  
Matthew Adesanya Adeleye ◽  
Simon Edward Connor ◽  
Simon Graeme Haberle
Keyword(s):  
Vegetation Change ◽  
Climatic Changes ◽  
The Holocene ◽  
Continental Scale ◽  
Western Africa ◽  
Chord Distance ◽  
Quantitative Synthesis ◽  
Climatic Regime ◽  
Pollen Records

Understanding long-term (centennial–millennial scale) ecosystem stability and dynamics are key to sustainable management and conservation of ecosystem processes under the currently changing climate. Fossil pollen records offer the possibility to investigate long-term changes in vegetation composition and diversity on regional and continental scales. Such studies have been conducted in temperate systems, but are underrepresented in the tropics, especially in Africa. This study attempts to synthesize pollen records from Nigeria (tropical western Africa) and nearby regions to quantitatively assess Holocene regional vegetation changes (turnover) and stability under different climatic regimes for the first time. We use the squared chord distance metric (SCD) to assess centennial-scale vegetation turnover in pollen records. Results suggest vegetation in most parts of Nigeria experienced low turnover under a wetter climatic regime (African Humid Period), especially between ~8000 and 5000 cal year BP. In contrast, vegetation turnover increased significantly under the drier climatic regime of the late-Holocene (between ~5000 cal year BP and present), reflecting the imp role of moisture changes in tropical west African vegetation dynamics during the Holocene. Our results are consistent with records of vegetation and climatic changes in other parts of Africa, suggesting the Holocene pattern of vegetation change in Nigeria is a reflection of continental-scale climatic changes.

scholarly journals Thermal structure and response to long-term climatic changes in Lake Qiandaohu, a deep subtropical reservoir in China

2014 ◽  
Vol 59 (4) ◽  
pp. 1193-1202 ◽  
Author(s):  
Yunlin Zhang ◽  
Zhixu Wu ◽  
Mingliang Liu ◽  
Jianbo He ◽  
Kun Shi ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Climatic Changes

scholarly journals Two decades of numerical modelling to understand long term fluvial archives: Advances and future perspectives

2017 ◽  
Vol 166 ◽  
pp. 177-187 ◽  
Author(s):  
A. Veldkamp ◽  
J.E.M. Baartman ◽  
T.J. Coulthard ◽  
D. Maddy ◽  
J.M. Schoorl ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Future Perspectives ◽  
Fluvial Archives

Stromal fibroblasts synthesize collagenase and stromelysin during long-term tissue remodeling

1993 ◽  
Vol 104 (4) ◽  
pp. 1001-1011
Author(s):  
M.T. Girard ◽  
M. Matsubara ◽  
C. Kublin ◽  
M.J. Tessier ◽  
C. Cintron ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Tissue Remodeling ◽  
Enzyme Synthesis ◽  
Stromal Fibroblasts ◽  
Repair Tissue ◽  
New Synthesis ◽  
Direct Support ◽  
Connective Tissue Remodeling ◽  
Specific Mrna

The process of connective tissue remodeling is an important mechanism contributing to tissue morphogenesis in development and homeostasis. Although it has long been known that remodeling tissues actively mediate collagenolysis, little is understood about the molecular mechanisms controlling this cell-regulated process. In this study, we examined the biosynthesis of collagenase and the related metalloproteinase, stromelysin, during remodeling of repair tissue deposited after mechanical injury to the rabbit cornea. Neither enzyme was synthesized by uninjured corneas; however, synthesis and secretion was detectable within one day after injury. Collagenase accumulated in its latent form while stromelysin appeared to be partially activated. Enzymes were synthesized by cells having a fibroblast phenotype. These cells were found within the stroma. New synthesis was correlated with accumulation of enzyme-specific mRNA. Highest levels of enzyme synthesis were observed in the repair tissue. However, stromal cells outside of the repairing area also synthesized both enzymes. The level of synthesis decreased in a gradient radiating from the repair tissue. Total synthetic levels in a given area of cornea were dependent on both the number of cells expressing enzyme and the rate of enzyme synthesis. Synthesis of collagenase was detected in repair tissue as long as nine months after injury. Our findings provide direct support for the hypothesis that new collagenase synthesis by cells in repair tissue is the first step in collagen degradation during long-term tissue remodeling.

scholarly journals Interannual and long-term changes in the trophic state of a multibasin lake: effects of morphology, climate, winter aeration, and beaver activity

2016 ◽  
Vol 73 (3) ◽  
pp. 445-460 ◽  
Author(s):  
Dale M. Robertson ◽  
William J. Rose ◽  
Paul C. Reneau
Keyword(s):  
Water Quality ◽  
Trophic State ◽  
Secchi Depth ◽  
Climatic Changes ◽  
Main Flow ◽  
Temperature And Precipitation ◽  
Air Temperatures ◽  
Long Term Changes ◽  
P Sources

Little St. Germain Lake (LSG), a relatively pristine multibasin lake in Wisconsin, USA, was examined to determine how morphologic (internal), climatic (external), anthropogenic (winter aeration), and natural (beaver activity) factors affect the trophic state (phosphorus, P; chlorophyll, CHL; and Secchi depth, SD) of each of its basins. Basins intercepting the main flow and external P sources had highest P and CHL and shallowest SD. Internal loading in shallow, polymictic basins caused P and CHL to increase and SD to decrease as summer progressed. Winter aeration used to eliminate winterkill increased summer internal P loading and decreased water quality, while reductions in upstream beaver impoundments had little effect on water quality. Variations in air temperature and precipitation affected each basin differently. Warmer air temperatures increased productivity throughout the lake and decreased clarity in less eutrophic basins. Increased precipitation increased P in the basins intercepting the main flow but had little effect on the isolated deep West Bay. These relations are used to project effects of future climatic changes on LSG and other temperate lakes.

scholarly journals Climatic-change implications from long-term (1823-1994) ice records for the Laurentian Great Lakes

1995 ◽  
Vol 21 ◽  
pp. 383-386 ◽  
Author(s):  
R.A. Assel ◽  
D.M. Robertson ◽  
M.H. Hoff ◽  
J.H. Selgeby
Keyword(s):  
Great Lakes ◽  
Climatic Changes ◽  
The Other ◽  
Laurentian Great Lakes ◽  
Great Lakes Region ◽  
Lake Mendota ◽  
Air Temperatures ◽  
The 1960S ◽  
Different Parts

Long-term ice records (1823-1994) from six sites in different parts of the Laurentian Great Lakes region were used to show the type and general timing of climatic changes throughout the region. The general timing of both freeze-up and ice loss varies and is driven by local air temperatures, adjacent water bodies and mixing, and site morphometry. Grand Traverse Bay and Buffalo Harbor represent deeper-water environments affected by mixing of off-shore waters; Chequamegon Bay, Menominee, Lake Mendota, and Toronto Harbor represent relatively shallow-water, protected environments. Freeze-up dates gradually became later and ice-loss dates gradually earlier from the start of records to the 1890s in both environments, marking the end of the “Little lce Age”. After this, freeze-up dates remained relatively constant, suggesting little change in early-winter air temperatures during the 20th century. Ice-loss dates at Grand Traverse Bay and Baffalo Harbor but not at the other sites became earlier during the 1940s and 1970s and became later during the 1960s. The global warming of the 1980s was marked by a trend toward earlier ice-loss dates in both environments.

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