Terrigenous Signals in Sediments of the Low-Latitude Atlantic - Indications to Environmental Variations during the Late Quaternary: Part II: Lithogenic Matter

Zabel, Matthias; Wagner, Thomas; Menocal, Peter de

doi:10.1007/978-3-642-18917-3_16

Cited by 18 publications

(11 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Southern hemisphere variables are for December (insolation) and DJF (precipitation) in-phase response of the monsoon to orbital forcing, other studies have inferred a mix of orbital forcing and glacial forcing influences on the North African monsoon (deMenocal 2004). Zabel et al (2003) used a 240,000-year record of fluvial deposits from the Niger delta to infer that the African monsoon responded to orbital forcing at the precession period but with a phase lag of about 65°( 4,000 years) and to a precessional component of glacial forcing with a phase lag of about 180°(i.e., strongest monsoons with weakest glacial forcing). Yuan et al (2004) used a 160,000-year record of isotopic ratios from stalagmites in two caves in southern China to infer an in-phase relationship between the Asian monsoon and JJA insolation, particularly for the largest insolation excursions during the last interglacial (they note that the abruptness of onset or termination may be related to higher latitude forcing).…”

Section: North Africamentioning

confidence: 99%

Simulation of the evolutionary response of global summer monsoons to orbital forcing over the past 280,000 years

et al. 2007

View full text Add to dashboard Cite

We describe the evolutionary response of northern and southern hemisphere summer monsoons to orbital forcing over the past 280,000 years using a fully coupled general circulation ocean-atmosphere model in which the orbital forcing is accelerated by a factor of 100. We find a strong and positive response of northern (southern) summer monsoon precipitation to northern (southern) summer insolation forcing. On average, July (January) precipitation maxima and JJA (DJF) precipitation maxima have high coherence and are approximately in phase with June (December) insolation maxima, implying an average lag between forcing and response of about 30°o f phase at the precession period. The average lag increases to over 40°for 4-month precipitation averages, JJAS (DJFM). The phase varies from region to region. The average JJA (DJF) land temperature maxima also lag the June orbital forcing maxima by about 30°of phase, whereas ocean temperature maxima exhibit a lag of about 60°of phase at the precession period. Using generalized measures of the thermal and hydrologic processes that produce monsoons, we find that the summer monsoon precipitation indices for the six regions all fall within the phase limits of the process indices for the respective hemispheres. Selected observational studies from four of the six monsoon regions report approximate in-phase relations of summer monsoon proxies to summer insolation. However other observational studies report substantial phase lags of monsoon proxies and a strong component of forcing associated with glacial-age boundary conditions or other factors. An important next step will be to include glacial-age boundary condition forcing in long, transient paleoclimate simulations, along with orbital forcing.

show abstract

Section: North Africamentioning

confidence: 99%

Simulation of the evolutionary response of global summer monsoons to orbital forcing over the past 280,000 years

et al. 2007

View full text Add to dashboard Cite

show abstract

“…During the summer months, when the ITCZ is located near 10°N, the Sahel region is especially arid, allowing the Saharan Air Layer (SAL) to transport dust toward the tropical Atlantic Ocean and the Caribbean ( Fig. 2; Zabel et al, 2003). During winter, a smaller dust plume is carried into South America, and away from the Cariaco Basin, by the northeast trade winds (Fig.…”

Section: Eolian Inputsmentioning

confidence: 97%

“…It is assumed that most of the eolian material found in the Cariaco Basin originates in the Saharan desert (Fig. 2;Zabel et al, 2003). During the summer months, when the ITCZ is located near 10°N, the Sahel region is especially arid, allowing the Saharan Air Layer (SAL) to transport dust toward the tropical Atlantic Ocean and the Caribbean ( Fig.…”

Section: Eolian Inputsmentioning

confidence: 99%

See 1 more Smart Citation

Quantifying the seasonal variations in fluvial and eolian sources of terrigenous material to Cariaco Basin, Venezuela

Elmore

Thunell

Styles

et al. 2009

Journal of South American Earth Sciences

View full text Add to dashboard Cite

“…The circulation patterns of the Brazil Current and North Brazil Current in the South Atlantic (Soutelino et al 2013), sedimentation events on the coastal plain that caused fluctuations in the sea level during the Last Glacial Maximum at the beginning of the Holocene (Andrade et al 2003), and the effects of the Intertropical Convergence Zone at low latitudes (Zabel et al 2003) may all have influenced the distribution of the species in coastal environments, resulting in asynchrony in the process of population expansion in different geographic areas (Souza et al 2015). Regional and local oceanic circulation patterns (Teixeira et al 2013) may also play an important role in the dispersal of eggs, as well as the recruitment of larvae and juveniles (Nonaka et al 2000).…”

Section: Population Structuringmentioning

confidence: 99%

Mitochondrial DNA evidences reflect an incipient population structure in Atlantic goliath grouper (<em>Epinephelus itajara</em>, Epinephelidae) in Brazil

Damasceno¹,

Siccha-Ramírez²,

Morales³

et al. 2015

Sci. Mar.

View full text Add to dashboard Cite

Summary:The Atlantic goliath grouper is a critically endangered species that inhabits estuarine and reef environments and is threatened primarily by fishing activities and habitat destruction. Despite the urgent need for protection, its genetic conservation status remains unknown. The aim of the present study was to evaluate the gene flow among the populations of the species along the coast of Brazil based on the control region of the mitochondrial DNA. The results indicate low haplotype diversity (0.40-0.86) and very low nucleotide diversity (0.1-0.5%). They also show that the genetic diversity of the species varies considerably along the coast and that this finding may be especially important for the identification of priority areas for its conservation. The population analyses indicate a low but significant degree of genetic structuring (Φ ST =0.111), probably due to the occurrence of rare haplotypes at some locations, although the genetic differentiation between sites was not correlated with geographic distance (r=0.0501; p=0.7719), and the shared haplotypes indicate that gene flow occurs among all locations along the Brazilian coast. The results of the pairwise F ST indicate a high degree of genetic differentiation between locations. The incipient population structuring detected in the present study is not related systematically to the geological or physical features of the Brazilian coast. The complex interaction of fluctuations in sea level, marine currents, and the reproductive characteristics of the species hampers the identification of the specific role of each of these processes in the gene flow dynamics of the population units of the Atlantic goliath grouper. The low overall levels of genetic diversity, the pairwise F ST values and the significant population structuring among groups (Φ CT ) identified in the present study all reinforce the critically endangered status of the species and are inconsistent with the presence of a single, panmictic population of groupers on the Brazilian coast. The results of this study suggest that, though it may be incipient, the observed genetic structuring must be taken into account in order to prevent potential problems, such as outbreeding depression, in the management of wild stocks.Keywords: critically endangered species; gene flow; genetic diversity; marine fish; western Atlantic Ocean.Evidencias en el ADN mitocondrial reflejan una incipiente estructuración poblacional en el mero guasa del Atlántico (Epinephelus itajara, Epinephelidae) en Brasil Resumen: El mero guasa del Atlántico está críticamente en peligro, habita en ambientes estuarinos y arrecifes, los cuáles están amenazados principalmente por las actividades de pesca y la destrucción de su hábitat. A pesar de la necesidad urgente de protección, su estado de conservación genética aún es desconocido. El objetivo del presente estudio fue evaluar el flujo génico entre las poblaciones de esta especie a lo largo de la costa de Brasil analizando la variabilidad genética de la región control del ADN mitocondrial....

show abstract

Terrigenous Signals in Sediments of the Low-Latitude Atlantic - Indications to Environmental Variations during the Late Quaternary: Part II: Lithogenic Matter

Cited by 18 publications

References 91 publications

Simulation of the evolutionary response of global summer monsoons to orbital forcing over the past 280,000 years

Simulation of the evolutionary response of global summer monsoons to orbital forcing over the past 280,000 years

Quantifying the seasonal variations in fluvial and eolian sources of terrigenous material to Cariaco Basin, Venezuela

Mitochondrial DNA evidences reflect an incipient population structure in Atlantic goliath grouper (<em>Epinephelus itajara</em>, Epinephelidae) in Brazil

Contact Info

Product

Resources

About