scholarly journals FAME (v1.0): a simple module to simulate the effect of planktonic foraminifer species-specific habitat on their oxygen isotopic content

2017 ◽  
Author(s):  
Didier M. Roche ◽  
Claire Waelbroeck ◽  
Brett Metcalfe ◽  
Thibaut Caley
Keyword(s):  
Data Model ◽  
Late Holocene ◽  
Simple Module ◽  
Climatic Conditions ◽  
Data Sets ◽  
Planktonic Foraminifer ◽  
Planktonic Foraminifers ◽  
Oxygen Isotopic ◽  
Species Specific ◽  
Almost All

Abstract. The oxygen-18 signal recorded in fossil planktonic foraminifer shells has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species generally yield distinct oxygen-18 signals, as a consequence of their specific living habitats in the water column and along the year. This complexity is usually not taken into account in data – model integration studies. To overcome this shortcoming, we developed the FAME (Foraminifers As Modeled Entities) module. The module predicts the presence or absence of commonly used planktonic foraminifers, and their oxygen-18 values. It is only forced by hydrographic data and uses a very limited number of parameters, almost all derived from culture experiments. FAME performance is evaluated using MARGO Late Holocene planktonic foraminifer calcite oxygen-18 and abundances data sets. The application of FAME to a simple cooling scenario demonstrates its utility to predict changes in planktonic foraminifer oxygen-18 in response to changing climatic conditions.

scholarly journals FAME (v1.0): a simple module to simulate the effect of planktonic foraminifer species-specific habitat on their oxygen isotopic content

2018 ◽  
Vol 11 (9) ◽  
pp. 3587-3603 ◽  
Author(s):  
Didier M. Roche ◽  
Claire Waelbroeck ◽  
Brett Metcalfe ◽  
Thibaut Caley
Keyword(s):  
Late Holocene ◽  
Simple Module ◽  
Climatic Conditions ◽  
Model Data ◽  
Planktonic Foraminifer ◽  
Planktonic Foraminifers ◽  
Oxygen Isotopic ◽  
Species Specific ◽  
Almost All ◽  
Multiproxy Approach

Abstract. The oxygen-18 to oxygen-16 ratio recorded in fossil planktonic foraminifer shells has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species generally yield distinct signals, as a consequence of their specific living habitats in the water column and along the year. This complexity is usually not taken into account in model–data integration studies. To overcome this shortcoming, we developed the Foraminifers As Modeled Entities (FAME) module. The module predicts the presence or absence of commonly used planktonic foraminifers and their oxygen-18 values. It is only forced by hydrographic data and uses a very limited number of parameters, almost all derived from culture experiments. FAME performance is evaluated using the Multiproxy Approach for the Reconstruction of the Glacial Ocean surface (MARGO) Late Holocene planktonic foraminifer calcite oxygen-18 and abundance datasets. The application of FAME to a simple cooling scenario demonstrates its utility to predict changes in planktonic foraminifer oxygen-18 to oxygen-16 ratio in response to changing climatic conditions.

scholarly journals Mid-to-late Holocene Temperature Evolution and Atmospheric Dynamics over Europe in Regional Model Simulations

2016 ◽  
Author(s):  
Emmanuele Russo ◽  
Ulrich Cubasch
Keyword(s):  
Late Holocene ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Climatic Conditions ◽  
Modes Of Variability ◽  
The North ◽  
Climate Reconstructions ◽  
The North Atlantic Oscillation ◽  
Almost All

Abstract. The improvement in resolution of climate models is always been mentioned as one of the most important factors when investigating past climatic conditions especially in order to evaluate and compare the results against proxy data. In this paper we present for the first time a set of high resolution simulations for different time slices of mid-to-late Holocene performed over Europe using a Regional Climate Model. Through a validation against a new pollen-based climate reconstructions dataset, covering almost all of Europe, we test the model performances for paleoclimatic applications and investigate the response of temperature to variations in the seasonal cycle of insolation, with the aim of clarifying earlier debated uncertainties, giving physically plausible interpretations of both the pollen data and the model results. The results reinforce previous findings showing that summertime temperatures were driven mainly by changes in insolation and that the model is too sensitive to such changes over Southern Europe, resulting in drier and warmer conditions. In winter, instead, the model does not reproduce correctly the same amplitude of changes, even if it captures the main pattern of the pollen dataset over most of the domain for the time periods under investigation. Through the analysis of variations in atmospheric circulation we suggest that, even though in some areas the discrepancies between the two datasets are most likely due to high pollen uncertanties, in general the model seems to underestimate the changes in the amplitude of the North Atlantic Oscillation, overestimating the contribution of secondary modes of variability

Fossil rodents in Mylodon Cave as indicators of late Pleistocene–Holocene environmental evolution in southern Chile

2021 ◽  
pp. 1-17
Author(s):  
Ulyses F.J. Pardiñas ◽  
Luis Borrero ◽  
Fabiana M. Martin ◽  
Mauricio Massone ◽  
Fernando J. Fernández
Keyword(s):  
Late Pleistocene ◽  
Small Mammal ◽  
Late Holocene ◽  
Environmental Changes ◽  
First Record ◽  
Climatic Conditions ◽  
Southern Chile ◽  
Environmental Evolution ◽  
Local Conditions ◽  
Almost All

Abstract We conducted the first taphonomic and paleoenvironmental study based on late Pleistocene–Holocene small mammal remains recovered from the famous Mylodon Cave (Cerro Benítez area, Última Esperanza, Chile). Most of the analyzed material came from the extensive excavations made by Earl Saxon in 1976. We also studied late Holocene small mammal samples of the neighboring rock shelter Dos Herraduras 1. Analyzed remains were mostly produced by owls, probably living inside the caves. In Mylodon Cave, the higher values of girdle bones are consistent with a windblown litter. We recorded nine species of rodents, seven cricetids, and two caviomorphs; almost all the identified taxa integrate recent local communities. Late Pleistocene–Holocene assemblages are characterized by the chinchilla rat Euneomys, indicating unforested areas around the caves under cold and moist climatic conditions. Middle Holocene amelioration is reflected by incremental rodent species richness, including the first record of taxa clearly associated with forest (e.g., Abrothrix lanosa). Late Holocene assemblages are markedly stable, indicating local conditions similar to the current (historical) environment. Quaternary rodents from Cerro Benítez area do not indicate abrupt environmental changes during middle–late Holocene, but a progressive trend towards forest increase.

scholarly journals Reproductive traits and floral visitors of Aechmea distichantha plants growing in different habitats of a South American xerophytic forest

Rodriguésia ◽  
2018 ◽  
Vol 69 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Rodrigo M. Freire ◽  
Ignacio M. Barberis ◽  
José L. Vesprini
Keyword(s):  
Reproductive Traits ◽  
Climatic Conditions ◽  
Similar Proportion ◽  
South American ◽  
The Sun ◽  
Carpenter Bee ◽  
Carpenter Bees ◽  
Vegetative Traits ◽  
Floral Visitors ◽  
Almost All

Abstract Aechmea distichantha, a widely-distributed facultative epiphytic bromeliad species, is present from rainforests to xerophytic forests. At its southernmost distribution (Humid Chaco) it grows in the understory and forest edges. This animal-pollinated bromeliad shows high phenotypic plasticity on its vegetative traits, but there is no information about plasticity on its reproductive traits. Infructescences from shade plants were heavier, had longer rachis, more spikelets, higher number of fruits/spikelet and higher number of seeds/fruit than those from sun plants, but they presented similar number of open flowers. The number of visitation events was similar in both habitats, but more flowers were visited in the sun than in the shade. Flowers were visited by seven species (six insects and one hummingbird). In the sun, the carpenter bee was the most frequent visitor and visited almost all flowers, whereas in the shade different species of visitors attained similar proportion of visits and number of visited flowers. Despite visitation events were similar in both habitats, plants growing in the shade set more seeds/fruit than plants growing in the sun. The higher proportion of visits accomplished by carpenter bees compared to hummingbirds is probably a consequence of the climatic conditions in the austral location of these populations.

scholarly journals Occurrence ofBordetellaInfection in Pigs in Northern India

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sandeep Kumar ◽  
Bhoj R. Singh ◽  
Monika Bhardwaj ◽  
Vidya Singh
Keyword(s):  
Plasmid Profile ◽  
Antigen Detection ◽  
Bordetella Bronchiseptica ◽  
Atrophic Rhinitis ◽  
Serum Samples ◽  
Northern India ◽  
Antimicrobial Sensitivity ◽  
Nasal Swabs ◽  
Species Specific ◽  
Almost All

Bordetella bronchisepticainfection causing atrophic rhinitis in pigs is reported from almost all countries. In the present study, occurrence ofBordetellainfection in apparently healthy pigs was determined in 392 pigs sampled to collect 358 serum samples and 316 nasal swabs from Northern India by conventional bacterioscopy, detection of antigen with multiplex polymerase chain reaction (mPCR), and detection of antibodies with microagglutination test (MAT) and enzyme linked immune-sorbent assay (ELISA).Bordetella bronchisepticacould be isolated from six (1.92%) nasal swabs. Although isolates varied significantly in their antimicrobial sensitivity, they had similar plasmid profile. The genus specific and species specific amplicons were detected from 8.2% and 4.4% nasal swabs using mPCR withalcgene (genus specific) andflagene andfim2 gene (species specific) primers, respectively. Observations revealed that there may be other bordetellae infecting pigs because about 50% of the samples positive using mPCR for genus specific amplicons failed to confirm presence ofB. bronchiseptica. Of the pig sera tested with MAT and ELISA forBordetellaantibodies, 67.6% and 86.3% samples, respectively, were positive. For antigen detection mPCR was more sensitive than conventional bacterioscopy while for detection of antibodies neither of the two tests (MAT and ELISA) had specificity in relation to antigen detection. Study indicated high prevalence of infection in swine herds in Northern India.

scholarly journals Global Tree Taper Modelling: A Review of Applications, Methods, Functions, and Their Parameters

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 913
Author(s):  
Serajis Salekin ◽  
Cristian Higuera Catalán ◽  
Daniel Boczniewicz ◽  
Darius Phiri ◽  
Justin Morgenroth ◽  
...  
Keyword(s):  
Measurement Techniques ◽  
Principal Component ◽  
Climatic Conditions ◽  
Modern Times ◽  
Taper Function ◽  
Complex Functions ◽  
Artificial Neural Network Ann ◽  
Species Specific ◽  
Simple Equations ◽  
Taper Equations

Taper functions are important tools for forest description, modelling, assessment, and management. A large number of studies have been conducted to develop and improve taper functions; however, few review studies have been dedicated to addressing their development and parameters. This review summarises the development of taper functions by considering their parameterisation, geographic and species-specific limitations, and applications. This study showed that there has been an increase in the number of studies of taper function and contemporary methods have been developed for the establishment of these functions. The reviewed studies also show that taper functions have been developed from simple equations in the early 1900s to complex functions in modern times. Early taper functions included polynomial, sigmoid, principal component analysis (PCA), and linear mixed functions, while contemporary machine learning (ML) approaches include artificial neural network (ANN) and random forest (RF). Further analysis of the published literature also shows that most of the studies of taper functions have been carried out in Europe and the Americas, meaning most taper equations are not specifically applicable to tropical tree species. Developing well-conditioned taper functions requires reducing the variation due to species, measurement techniques, and climatic conditions, among other factors. The information presented in this study is important for understanding and developing taper functions. Future studies can focus on developing better taper functions by incorporating emerging remote sensing and geospatial datasets, and using contemporary statistical approaches such as ANN and RF.

Tree line shifts, changing vegetation assemblages and permafrost dynamics on Galdhøpiggen (Jotunheimen, Norway) over the past ~4400 years

The Holocene ◽  
2021 ◽  
pp. 095968362110665
Author(s):  
Helen Hallang ◽  
Cynthia A Froyd ◽  
John F Hiemstra ◽  
Sietse O Los
Keyword(s):  
Scots Pine ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Tree Line ◽  
Peat Core ◽  
Modern Pollen ◽  
Modern Analogue ◽  
Downy Birch

An environmental reconstruction based on palynological evidence preserved in peat was carried out to examine late-Holocene alpine tree line dynamics in the context of past climatic changes on Galdhøpiggen (Jotunheimen, southern Norway). We analysed a peat core taken from a mire at the present-day tree line (1000 m a.s.l.), c. 450 m downslope from the lower limit of sporadic permafrost. We adopted a combination of commonly used indicators of species’ local presence to reconstruct past vegetation assemblages, such as the relative pollen abundance (%), pollen accumulation rate (PAR), and presence of indicator species. Additionally, fossil pollen from the peat sequence was compared to modern pollen from a surface moss polster to establish a modern analogue. The results were compared with studies covering the late-Holocene climatic changes in the area. The reconstruction demonstrates that a pine-dominated woodland reached above the present-day tree line at c. 4300 cal. yr BP, suggesting a warmer climate suitable for Scots pine ( Pinus sylvestris) growth at this altitude. Scots pine retreated to lower altitudes between c. 3400 and 1700 cal. yr BP, accompanied by the descent of the low-alpine shrub-dominated belt, in response to cooling climatic conditions. The colder period covered c. 1700–170 cal. yr BP, and an open downy birch ( Betula pubescens) woodland became widespread at 1000 m a.s.l., whilst pine remained sparse at this altitude. From c. 170 cal. yr BP onwards, warming allowed pine to re-establish its local presence alongside downy birch at 1000 m a.s.l.

The use of natural conditions of the high alpine province of Dagestan for reproduction of prospective varieties and hybrids of potato

2021 ◽  
pp. 34-37
Author(s):  
В.К. Сердеров ◽  
Д.В. Сердерова
Keyword(s):  
Field Experiments ◽  
Climatic Conditions ◽  
High Yield ◽  
Potato Varieties ◽  
Caspian Lowland ◽  
The Republic ◽  
High Yielding Varieties ◽  
Almost All ◽  
The Cost ◽  
Mountain Province

Большое значение в увеличении продуктивности картофеля имеет внедрение в производство перспективных высокоурожайных сортов и гибридов, приспособленных к местным природно-климатическим условиям возделывания, от чего зависят эффективность отрасли и себестоимость продукции. Цель работы – изучить влияние климатических условий на продуктивность и качественные показатели сортов и гибридов картофеля, а также использование ими благоприятных почвенно-климатических условий высокогорья Республики Дагестан, для размножения и внедрения в производство новых перспективных, высокоурожайных, приспособленных к условиям среды выращивания сортов картофеля с комплексом хозяйственно-ценных признаков. Объектом изучения послужили сорта картофеля раннего, среднераннего и среднего сроков созревания российской, белорусской и иностранной селекции. Полевые опыты закладывали в 2014–2017 годах на высоте 2000–2200 м, на землях горного опорного пункта «Курахский» Курахского района и на равнинной провинции (Прикаспийской низменности) на территории дачного массива «Наука» Махачкалинского района Республики Дагестан. Схема посадки – 70×30 см, повторность – четырехкратная. Технология выращивания картофеля – гребневая. При проведении полевых опытов использовали общепринятые методики. Практически все сорта картофеля, выращенные на равнинной провинции, сформировали высокий урожай в первый год и при дальнейшем размножении в результате развития вирусных болезней резко снизили свои продуктивные качества. Наиболее высокая урожайность в среднем за три года отмечена у сортов Жуковский ранний (20,8 т/га), Импала (20,5 т/га), Невский (17,8 т/га), Предгорный (16,9 т/га) и Удача (16,3 т/га). В свою очередь, горная провинция Дагестана характеризовалась благоприятными почвенно-климатическими условиями для возделывания как продовольственного картофеля, так и для организации первичного семеноводства на безвирусной основе и размножения перспективных сортов этой культуры. В среднем за годы исследований в горной провинции по урожайности выделились сорта Сильвана (37,4 т/га), Удача (37,6 т/га), Рокко (33,3 т/га), Импала (31,7 т/га), Жуковский ранний (29,0 т/га), Предгорный (27,7 т/га) и Примобелла (27,7 т/га), а также гибриды № 12.40/17 (43,1 т/га) и № 13.61/61 (38,8 т/га). The introduction of promising high-yielding varieties and hybrids adapted to the local natural and climatic conditions of cultivation is of great importance in increasing the productivity of potatoes, which determines the efficiency of the industry and the cost of production. The aim of the work is to study the influence of climatic conditions on the productivity and quality indicators of potato varieties and hybrids, as well as their use of favorable soil and climatic conditions in the highlands of the Republic of Dagestan, for breeding and introducing into production new promising, high-yielding, adapted to the growing environment of potato varieties with a complex of economically valuable characteristics. The object of the study was potato varieties of early, mid-early and medium maturation periods of Russian, Belarusian and foreign selection. Field experiments were conducted in 2014–2017 at an altitude of 2000–2200 m, on the lands of the mountain stronghold Kurakhsky of the Kukhar district and on the plain province (the Caspian lowland) on the territory of the suburban area Nauka of the Makhachkala district of the Republic of Dagestan. The landing scheme is 70×30 cm, the repeatability is four times. The technology of growing potatoes is combed. When conducting field experiments, generally accepted methods were used. Almost all potato varieties grown in the lowland province formed a high yield in the first year and, with further propagation, as a result of the development of viral diseases, sharply reduced their productive qualities. The highest yield on average for three years was observed in the varieties Zhukovskiy ranniy (20.8 t/ha), Impala (20.5 t/ha), Nevsky (17.8 t/ha), Predgornyy (16.9 t/ha) and Udacha (16.3 t/ha). In turn, the mountain province of Dagestan was characterized by favorable soil and climatic conditions for the cultivation of both food potatoes, and for the organization of primary seed production on a virus-free basis and the reproduction of promising varieties of this crop. On average, over the years of research in the mountain province, the varieties Silvana (37.4 t/ha), Udacha (37.6 t/ha), Rocco (33.3 t/ha), Impala (31.7 t/ha), Zhukovskiy ranniy (29.0 t/ha), Predgornyy (27.7 t/ha) and Primobella (27.7 t/ha), as well as hybrids No.12.40/17 (43.1 t/ha) and No.13.61/61 (38.8 t/ha) were distinguished by yield.

Human occupation strategies and related environmental-climate during the middle and late Holocene in central Pampas of Argentina

The Holocene ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 244-261 ◽  
Author(s):  
Pablo G Messineo ◽  
Marcela S Tonello ◽  
Silvina Stutz ◽  
Alfonsina Tripaldi ◽  
Nahuel Scheifler ◽  
...  
Keyword(s):  
Late Holocene ◽  
Specific Activity ◽  
Climatic Conditions ◽  
Hard Material ◽  
Human Occupation ◽  
Climate Conditions ◽  
Lithic Assemblage ◽  
Depositional Rate ◽  
Archeological Site ◽  
Middle And Late Holocene

The main objective of this work is to generate and integrate interpretations of human occupation strategies and inferences of the environmental-climatic conditions in the central Pampas during the middle and late Holocene. We present a novel archeological–geological–paleoecological analysis in the area of the Cabeza de Buey lake, placed in an aeolian landscape. During the middle Holocene, two events of human occupations were recognized at Laguna Cabeza de Buey 2 archeological site. Both events present a small amount of lithic materials, a low diversity of tools and activities developed with them (principally hard material), and the hunting and primary processing of artiodactyls. These evidences suggest a locus of specific activity associated with an ephemeral human settlement under climate conditions drier than present and the presence of small, brackish, and shallow water bodies. For the late late Holocene, the hunter-gatherer occupation has a higher depositional rate of lithic assemblage, stones with diverse origins, presence of pottery fragments, a great lithic tool diversity, knapping techniques, and activities developed with these tools (processing wood, bone, hide, non-woody plant, and soft material). These evidences reveal an occupation with a higher degree of recurrence represented by a locus of multiple activities associated with a more stable landscape, such as an environment of dunes fixed by grass vegetation, and the establishment of a permanent water body. The different environmental characteristics for the middle and late Holocene in this area promoted that human groups develop two different patterns of mobility, settlement and use of space.

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