The response of calcareous nannoplankton to sea surface variability at Ceara Rise during the early Pleistocene glacial-interglacial cycles

2019 ◽  
Vol 138 (1) ◽  
pp. 1-14
Author(s):  
Alessandro Incarbona ◽  
Enrico Di Stefano ◽  
Patrizia Maiorano ◽  
Maria Marino ◽  
Nicola Pelosi
Keyword(s):  
Sea Surface ◽  
Early Pleistocene ◽  
Calcareous Nannoplankton ◽  
Surface Variability ◽  
Ceara Rise

scholarly journals Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling

2013 ◽  
Vol 10 (3) ◽  
pp. 5535-5554
Author(s):  
J. Etourneau ◽  
R. S. Robinson ◽  
P. Martinez ◽  
R. Schneider
Keyword(s):  
Nutrient Supply ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Early Pleistocene ◽  
High Latitudes ◽  
Export Production ◽  
Eastern Equatorial Pacific ◽  
Nutrient Consumption ◽  
High Nutrient ◽  
High Nutrient Supply

Abstract. The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (δ15N) and alkenone-derived sea surface temperature (SST) values. This ~ 0.6 million years long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.

scholarly journals Late Pliocene Cordilleran Ice Sheet development with warm northeast Pacific sea surface temperatures

2020 ◽  
Vol 16 (1) ◽  
pp. 299-313 ◽  
Author(s):  
Maria Luisa Sánchez-Montes ◽  
Erin L. McClymont ◽  
Jeremy M. Lloyd ◽  
Juliane Müller ◽  
Ellen A. Cowan ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ice Sheet ◽  
Gulf Of Alaska ◽  
Sea Surface ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Subarctic Pacific ◽  
Cordilleran Ice Sheet ◽  
Forcing Mechanisms ◽  
Atmospheric Co2 Concentrations

Abstract. The initiation and evolution of the Cordilleran Ice Sheet are relatively poorly constrained. International Ocean Discovery Program (IODP) Expedition 341 recovered marine sediments at Site U1417 in the Gulf of Alaska (GOA). Here we present alkenone-derived sea surface temperature (SST) analyses alongside ice-rafted debris (IRD), terrigenous, and marine organic matter inputs to the GOA through the late Pliocene and early Pleistocene. The first IRD contribution from tidewater glaciers in southwest Alaska is recorded at 2.9 Ma, indicating that the Cordilleran Ice Sheet extent increased in the late Pliocene. A higher occurrence of IRD and higher sedimentation rates in the GOA during the early Pleistocene, at 2.5 Ma, occur in synchrony with SSTs warming on the order of 1 ∘C relative to the Pliocene. All records show a high degree of variability in the early Pleistocene, indicating highly efficient ocean–climate–ice interactions through warm SST–ocean evaporation–orographic precipitation–ice growth mechanisms. A climatic shift towards ocean circulation in the subarctic Pacific similar to the pattern observed during negative Pacific Decadal Oscillation (PDO) conditions today occurs with the development of more extensive Cordilleran glaciation and may have played a role through increased moisture supply to the subarctic Pacific. The drop in atmospheric CO2 concentrations since 2.8 Ma is suggested as one of the main forcing mechanisms driving the Cordilleran glaciation.

Investigations of the Tasman Sea by satellite altimetry

1984 ◽  
Vol 35 (6) ◽  
pp. 619 ◽  
Author(s):  
R Coleman
Keyword(s):  
Spatial Distribution ◽  
Satellite Data ◽  
Satellite Altimetry ◽  
Sea Surface ◽  
Altimeter Data ◽  
Winter Period ◽  
East Australian Current ◽  
Tasman Sea ◽  
Topographic Influence ◽  
Surface Variability

Altimeter data obtained over a period of 3.6 years (from April 1975 to November 1978) and over the winter period July-September 1978 from the GEOS-3 and SEASAT satellites were used to study the spatial distribution of mesoscale sea-surface variability in the Tasman Sea. Satellite data generally agreed with existing hydrographic measurements. Patterns of higher sea-surface variability were shown to be associated with the East Australian Current and eddy areas. Though the Tasman Front is known to be present at certain times of the year, it is concluded that it is not a permanent feature across the Tasman Sea. Low variability levels in the mid-Tasman Sea are seemingly dictated by the Lord Howe Rise, thus suggesting some sort of topographic influence.

scholarly journals Diurnal internal tides detected in the Adriatic

2006 ◽  
Vol 24 (11) ◽  
pp. 2773-2780 ◽  
Author(s):  
H. Mihanović ◽  
M. Orlić ◽  
Z. Pasarić
Keyword(s):  
Sea Level ◽  
Temperature Data ◽  
Internal Tides ◽  
Sea Surface ◽  
Sea Level Changes ◽  
Temperature Oscillations ◽  
Sea Level Oscillations ◽  
Wind Measurements ◽  
Diurnal Wind ◽  
Surface Variability

Abstract. Strong diurnal oscillations, documented by temperature data that were collected along a submarine cliff on the Lastovo Island (southern Adriatic), are studied and compared with sea level and wind measurements at Dubrovnik and Komiža (island of Vis). Three thermistors were deployed at the depths of 15, 22 and 36 m between March 2001 and March 2002. Pronounced diurnal temperature oscillations were detected at 15 and 22 m during the stratified season. The correlation between the sea surface and thermocline displacements was highest in June 2001, when diurnal wind changes were not significant, while diurnal sea level oscillations achieved annual maxima. Thermocline oscillations were in phase with sea level changes. The range of diurnal sea surface variability was close to 19 cm, while the range of corresponding thermocline variability was about 5.4 m. The findings summarize the outcome of the first dedicated study of internal tides in the Adriatic.

scholarly journals The Use of MTM-SVD Technique to Explore the Joint Spatiotemporal Modes of Wind and Sea Surface Variability in the North Indian Ocean during 1993–2005

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Thaned Rojsiraphisal ◽  
Balaji Rajagopalan ◽  
Lakshmi Kantha
Keyword(s):  
Indian Ocean ◽  
Ocean Model ◽  
North Indian Ocean ◽  
Sea Surface ◽  
Ocean Climate ◽  
Modes Of Variability ◽  
The North ◽  
Monsoon Variability ◽  
Value Decomposition ◽  
Surface Variability

Sea surface height (SSH) and sea surface temperature (SST) in the North Indian Ocean are affected predominantly by the seasonally reversing monsoons and in turn feed back on monsoon variability. In this study, a set of data generated from a data-assimilative ocean model is used to examine coherent spatiotemporal modes of variability of winds and surface parameters using a frequency domain technique, Multiple Taper Method with Singular Value Decomposition (MTM-SVD). The analysis shows significant variability at annual and semiannual frequencies in these fields individually and jointly. The joint variability of winds and SSH is significant at interannual (2-3 years) timescale related to the ENSO mode—with a “/dipole/” like spatial pattern. Joint variability with SST showed similar but somewhat weaker behavior. Winds appear to be the driver of variability in both SSH and SST at these frequency bands. This offers prospects for long-lead projections of the North Indian Ocean climate.

scholarly journals Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling

2013 ◽  
Vol 10 (8) ◽  
pp. 5663-5670 ◽  
Author(s):  
J. Etourneau ◽  
R. S. Robinson ◽  
P. Martinez ◽  
R. Schneider
Keyword(s):  
Nutrient Supply ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Early Pleistocene ◽  
High Latitudes ◽  
Export Production ◽  
Eastern Equatorial Pacific ◽  
Nutrient Consumption ◽  
High Nutrient ◽  
High Nutrient Supply

Abstract. The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene–Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (δ15N) and alkenone-derived sea surface temperature (SST) values. This ∼0.6 million year long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.

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