Abrupt (or millennial or suborbital) climatic variability: Heinrich events/stadials

2022 ◽  
pp. 181-187
Author(s):  
Samuel Toucanne ◽  
Filipa Naughton ◽  
Teresa Rodrigues ◽  
Natalia Vázquez-Riveiros ◽  
María Fernanda Sánchez Goñi
2000 ◽  
Vol 54 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Marı́a Fernanda Sánchez Goñi ◽  
Jean-Louis Turon ◽  
Frédérique Eynaud ◽  
Sandra Gendreau

Pollen, foraminifer, dinocyst, and coarse lithic high-resolution analyses and δ18O measurements have been carried out for the last-glacial section of marine core MD95-2042 located near the southwestern margin of the Iberian Peninsula. The pollen data indicate a high frequency of vegetational changes on the adjacent continent during this period, suggesting a climatic variability very similar to that of the Dansgaard-Oeschger cycles recorded by the Greenland ice cores. The detailed direct correlation of the terrestrial and marine proxy data from core MD95-2042 indicates a three-phase pattern of Heinrich events in land and ocean environments. The first and last phases of the H5 and H4 events are characterized by a mild and humid climate in southwestern Europe, probably associated with the European origin of the ice-rafted detritus. The middle phase exhibits a cold and dry climate in Iberia linked with the maximum input of ice-rafted detritus. This phase seems to correspond with the Laurentide ice-sheet surges. Between the Heinrich events, several cold and dry periods on land are correlated with stades of the Dansgaard-Oeschger cycles. The impact of the Dansgaard-Oeschger stades in southwestern Europe seems to be preferentially connected to the cold winter air masses reaching this mid-latitude region.


2009 ◽  
Vol 71 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Anne-Laure Daniau ◽  
Maria Fernanda Sánchez Goñi ◽  
Josette Duprat

AbstractHigh resolution multiproxy analysis (microcharcoal, pollen, organic carbon, Neogloboquadrina pachyderma (s), ice rafted debris) of the deep-sea record MD04-2845 (Bay of Biscay) provides new insights for understanding mechanisms of fire regime variability of the last glacial period in western France. Fire regime of western France closely follows Dansgaard–Oeschger climatic variability and presents the same pattern than that of southwestern Iberia, namely low fire regime associated with open vegetation during stadials including Heinrich events, and high fire regime associated with open forest during interstadials. This supports a regional climatic control on fire regime for western Europe through fuel availability for the last glacial period. Additionally, each of Heinrich events 6, 5 and 4 is characterised by three episodes of fire regime, with a high regime bracketed by lower fire regime episodes, related to vegetational succession and complex environmental condition changes.


2021 ◽  
pp. 1-16
Author(s):  
Hartmut Heinrich ◽  
Christoph Schmidt ◽  
Florian Ziemen ◽  
Uwe Mikolajewicz ◽  
Christopher-Bastian Roettig

Abstract New IRSL ages of eolianites close to Muñique (Lanzarote) demonstrate the influence of millennial scale climatic variability on the sedimentary dynamics on the Canary Islands during the last glacial cycle. The repetitive succession of interstadial and stadial climatic conditions formed multiple sequences of eolian deposits, each in general comprising three depositional types. DepoType 1 and DepoType 2 consist mainly of marine biogenic carbonate detritus with small amounts of dust from the Sahara representing interstadial conditions. DepoType 2 compared to DepoType 1 is characterized by larger amounts of land snails and calcified brood cells. A DepoType 3 rich in dust from African subtropical/tropical Latisols terminates a sequence. IRSL dating on DepoType 3 type deposits clearly shows that these were deposited during Heinrich Events under stadial conditions. The stadial cooling of the North Atlantic Ocean caused a southern shift of climate zones that culminated during Heinrich Events when the arctic climate reaches its most southerly extent. As a consequence, atmospheric changes led to massive dust supply from the then-dry Sahel. The increase in dust and precipitation from the dry DepoTypes 1 to the more humid DepoTypes 3 originates from a modified atmospheric dynamic during a millennial cycle.


2019 ◽  
Vol 56 (2) ◽  
pp. 51
Author(s):  
A. N. Sharov ◽  
V. N. Nikulina ◽  
A. A. Maximov ◽  

2018 ◽  
Vol 48 (4) ◽  
pp. 420-428
Author(s):  
Johana Juliet Caballero Vanegas ◽  
Karen Bibiana Mejía Zambrano ◽  
Lizeth Manuela Avellaneda-Torres

ABSTRACT Understanding the impacts of agricultural practices on soil quality indicators, such as enzymatic activities, is of great importance, in order to advance in their diagnosis and sustainable management. This study aimed to evaluate the effect of ecological and conventional agricultural managements on enzymatic activities of a soil under coffee agroecosystems. The enzymatic activities were associated with the biogeochemical cycles of nitrogen (urease and protease), phosphorus (acid and alkaline phosphatase) and carbon (β-glucosidase), during the rainy and dry seasons. Physical-chemical soil proprieties were also assessed and related to resilience scores linked to the climatic variability reported for the areas under study. The activities of urease, alkaline and acid phosphatase and ß-glucosidase were statistically higher in ecological agroecosystems than in conventional ones. This may be attributed to the greater application of organic waste in the ecological environment, as well as to the absence of pesticides and synthetic fertilizers, which allow better conditions for the microbial activity. The resilience scores to the climate variability that showed the highest correlations with the assessed enzymatic activities were: the farmers' knowledge on soil microorganisms, non-use of pesticides and synthetic fertilizers and non-dependence on external supplies. It was concluded that the enzymatic activities are modified by the management systems, being specifically favored by the ecological management. This agroecosystem, in the long term, ensures an efficient use of the soil resources, with a lower degradation and contamination.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Agata Keller ◽  
Somsubhra Chattopadhyay ◽  
Mikołaj Piniewski

Abstract Background Flow variability is considered a fundamental factor affecting riverine biota. Any alterations to flow regime can influence freshwater organisms, and this process is expected to change with the projected climate change. This systematic map, therefore, aims at investigating the impacts of natural (resulting from climatic variability), anthropogenic (resulting from direct human pressure), and climate change-induced flow variability on fish and macroinvertebrates of temperate floodplain rivers in Central and Western Europe. Particular focus will be placed on the effects of extreme low and high discharges. These rare events are known to regulate population size and taxonomic diversity. Methods All studies investigating the effects of flow variability on metrics concerning freshwater fish and macroinvertebrates will be considered in the map, particularly metrics such as: abundance, density, diversity, growth, migration, recruitment, reproduction, survival, or their substitutes, such as biomonitoring indices. Relevant flow variability will reflect (1) anthropogenic causes: dams, reservoirs, hydroelectric facilities, locks, levees, water abstraction, water diversion, land-use changes, road culverts; (2) natural causes: floods, droughts, seasonal changes; or (3) climate change. Geographically, the map will cover the ecoregion of Central and Western Europe, focusing on its major habitat type, namely “temperate floodplain rivers and wetlands”. The review will employ search engines and specialist websites, and cover primary and grey literature. No date, language, or document type restrictions will be applied in the search strategy. We expect the results to be primarily in English, although evidence (meeting all eligibility criteria) from other languages within the study area will also be included. We will also contact relevant stakeholders and announce an open call for additional information. Eligibility screening will be conducted at two levels: title and abstract, and full text. From eligible studies the following information will be extracted: the cause of flow variability, location, type of study, outcomes, etc. A searchable database containing extracted data will be developed and provided as supplementary material to the map report. The final narrative will describe the quantity and key characteristics of the available evidence, and identify knowledge gaps and knowledge clusters, i.e. subtopics sufficiently covered by existing studies allowing full systematic review and meta-analysis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. García-Cervigón ◽  
Pedro F. Quintana-Ascencio ◽  
Adrián Escudero ◽  
Merari E. Ferrer-Cervantes ◽  
Ana M. Sánchez ◽  
...  

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.


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