Linking Coniacian–Santonian (OAE3) Black-Shale Deposition to African Climate Variability: A Reference Section from the Eastern Tropical Atlantic at Orbital Time Scales (Odp Site 959, Off Ivory Coast and Ghana)

Author(s):  
BRITTA BECKMANN ◽  
THOMAS WAGNER ◽  
PETER HOFMANN
2016 ◽  
Vol 404 ◽  
pp. 208-209
Author(s):  
M.H. Simon ◽  
M. Ziegler ◽  
I.R. Hall ◽  
S. Barker ◽  
C. Stringer

2021 ◽  
Author(s):  
Phong V. V. Le ◽  
Hai V. Pham ◽  
Luyen K. Bui ◽  
Anh N. Tran ◽  
Chien V. Pham ◽  
...  

Abstract Groundwater is a critical component of water resources and has become the primary water supply for agricultural and domestic uses in the Vietnamese Mekong Delta (VMD). Widespread groundwater level declines have occurred in the VMD over recent decades, reflecting that extraction rates exceed aquifer recharge in the region. However, the impacts of climate variability on groundwater system dynamics in the VMD remain poorly understood. Here, we explore recent changes in groundwater levels in shallow and deep aquifers from observed wells in the VMD and investigate their relations to the annual precipitation variability and El Niño–Southern Oscillation (ENSO). We show that groundwater level responds to changes in annual precipitation at time scales of approximately 1 year. Moreover, shallow (deep) groundwater in the VMD appears to correlate with the ENSO over intra-annual (inter-annual) time scales. Our findings reveal a critical linkage between groundwater level changes and climate variability, suggesting the need to develop an understanding of the impacts of climate variability across time scales on water resources in the VMD.


2019 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Michael Iannicelli

Even though the author already incorporated the citation of Sinninghe-Damste & Schouten (2006) into the text of the paper, the author regrets having failed to include their full citation within the Reference Section of my above paper which is: Sinninghe-Damste, J. S. & Schouton, S. (2006). Biological markers for anoxia in the photic zone of the water column. In, Volkman, J. K. (ed.), Marine Organic Matter: Biomarkers, Isotopes and DNA, (pp. 127 – 163). The Handbook of Environmental Chemistry, vol. 2N. Springer: Berlin and Heidelberg. https://doi.org/10.1007/698_2_005 The author also needs to paraphrase a statement made in the last three lines of the 2nd paragraph on page 40 where it reads as: “Thus, we may conclude here that paleo-upfreezing of any conodont-element(s) originally buried in the pre-lithified, light-colored shale occurred in order to account for their presence in black shale”. Instead, in lieu of that statement, it should read as “At this point in time of the study, we may tentatively conclude here while completely concluding later in the study, that conodont-elements originally existing in the underlying, pre-lithified, light-colored shale, had to paleo-upfreeze vertically upward into pre-lithified, black shale sediment in order to account for their presence in lithified black shale”.


2021 ◽  
Author(s):  
Emilia Sanchez ◽  
Marta Martin Rey ◽  
Roland Seferian ◽  
Yeray Santana-Falcon

<p>The interannual climate variability in the Tropical Atlantic is mainly controlled by two air-sea coupled modes denoted as Meridional Mode (MM) and Equatorial Mode (EM). The MM, peaking in boreal spring, is characterized by an anomalous Sea Surface Temperature (SST) interhemispheric gradient associated with anomalous surface cross-equatorial winds blowing to the warmer hemisphere.  On the other hand, the positive phase of the EM exhibits an anomalous warming in the equatorial band and along the African coast, related to a weakening of the climatological trade winds. Both interannual modes illustrate significant SST and surface wind changes in the eastern boundary upwelling systems (EBUS) of the tropical Atlantic: the Senegal-Mauritanian and Angola-Benguela. The EBUS are characterized by wind-induced coastal upwelling of deep cold waters rich in nutrients supporting high primary productivity and an abundance of food resources. Hence, the physical or climate characteristics associated with the MM and EM may have a potential effect on marine organisms and ecosystems. The goal of this study is to understand the links between the main modes of tropical Atlantic variability and biogeochemical (BGC) variables such as oxygen, net primary production and ph. These are known to be the main drivers for marine ecosystems. Firstly we study the influence of MM and AM on the EBUS and how these links are represented by the coupled ESM CNRM-ESM2.1 against observations. Second, we use the ESM to investigate the links between the SST anomalies associated to MM and EM and the main BGC stressors mentioned above. For this purpose, a set of numerical experiments performed with CMIP6 climate models are used. This work is supported by the H2020 TRIATLAS project, whose main goal is to understand and evaluate the future evolution of living marine resources in the Atlantic Ocean.</p>


Author(s):  
Michael Schulz ◽  
Wolfgang H. Berger ◽  
Michael Baillie ◽  
Jürg Luterbacher ◽  
Jens Meincke ◽  
...  

2001 ◽  
Vol 14 (5) ◽  
pp. 638-655 ◽  
Author(s):  
Richard Seager ◽  
Yochanan Kushnir ◽  
Ping Chang ◽  
Naomi Naik ◽  
Jennifer Miller ◽  
...  

2018 ◽  
Vol 99 (11) ◽  
pp. 2341-2359 ◽  
Author(s):  
M. J. Roberts ◽  
P. L. Vidale ◽  
C. Senior ◽  
H. T. Hewitt ◽  
C. Bates ◽  
...  

AbstractThe time scales of the Paris Climate Agreement indicate urgent action is required on climate policies over the next few decades, in order to avoid the worst risks posed by climate change. On these relatively short time scales the combined effect of climate variability and change are both key drivers of extreme events, with decadal time scales also important for infrastructure planning. Hence, in order to assess climate risk on such time scales, we require climate models to be able to represent key aspects of both internally driven climate variability and the response to changing forcings. In this paper we argue that we now have the modeling capability to address these requirements—specifically with global models having horizontal resolutions considerably enhanced from those typically used in previous Intergovernmental Panel on Climate Change (IPCC) and Coupled Model Intercomparison Project (CMIP) exercises. The improved representation of weather and climate processes in such models underpins our enhanced confidence in predictions and projections, as well as providing improved forcing to regional models, which are better able to represent local-scale extremes (such as convective precipitation). We choose the global water cycle as an illustrative example because it is governed by a chain of processes for which there is growing evidence of the benefits of higher resolution. At the same time it comprises key processes involved in many of the expected future climate extremes (e.g., flooding, drought, tropical and midlatitude storms).


2004 ◽  
Vol 61 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Robert K. Booth ◽  
Stephen T. Jackson ◽  
Catherine E.D. Gray

We investigated the developmental and hydrological history of a Sphagnum-dominated, kettle peatland in Upper Michigan using testate amoebae, plant macrofossils, and pollen. Our primary objective was to determine if the paleohydrological record of the peatland represents a record of past climate variability at subcentennial to millennial time scales. To assess the role of millennial-scale climate variability on peatland paleohydrology, we compared the timing of peatland and upland vegetation changes. To investigate the role of higher-frequency climate variability on peatland paleohydrology, we used testate amoebae to reconstruct a high-resolution, hydrologic history of the peatland for the past 5100 years, and compared this record to other regional records of paleoclimate and vegetation. Comparisons revealed coherent patterns of hydrological, vegetational, and climatic changes, suggesting that peatland paleohydrology responded to climate variability at millennial to sub-centennial time scales. Although ombrotrophic peatlands have been the focus of most high-resolution peatland paleoclimate research, paleohydrological records from Sphagnum-dominated, closed-basin peatlands record high-frequency and low-magnitude climatic changes and thus represent a significant source of unexplored paleoclimate data.


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