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 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.

Cooling and freshening of the eastern equatorial Pacific over the last 2000 years

2020 ◽  
Author(s):  
Gerald Rustic ◽  
Athanasios Koutavas ◽  
Thomas Marchitto
Keyword(s):  
Stable Isotope ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Ice Age ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Eastern Equatorial Pacific

<p>Sea surface temperatures in the eastern equatorial Pacific exert powerful influence on the climate beyond the tropics through strong atmosphere-ocean coupling. Records of eastern Pacific sea surface temperatures are of vital importance for identifying the linkages between short-term climate variability and long-term climate trends. Here we reconstruct eastern equatorial Pacific sea surface temperature and salinity from paired trace metal and stable isotope analyses in foraminifera from a sediment core near the Galápagos Islands. Sea surface temperatures are correlated with reconstructed Northern and Southern hemisphere temperature records suggesting a common origin. We propose that this temperature signal originates in the extra-tropics and is transmitted to the eastern Pacific surface via its source waters. We find exceptions to this cooling during the Little Ice Age and during the last century, where notable sea surface temperature increases are observed. We calculate δ<sup>18</sup>O<sub>sw </sub>from paired stable isotope and trace element analyses and derive salinity, which reveals a significant trend toward fresher surface waters in the eastern equatorial Pacific. The overall trend toward cooler and fresher sea surface conditions is consistent with longer-term trends from both the Eastern and Western Pacific.</p>

Low soil temperature reduces the positive effects of high nutrient supply on the growth and biomass of white birch seedlings in ambient and elevated carbon dioxide concentrations

Botany ◽  
2009 ◽  
Vol 87 (10) ◽  
pp. 905-912 ◽  
Author(s):  
Titus Fondo Ambebe ◽  
Qing-Lai Dang ◽  
Jacob Marfo
Keyword(s):  
Carbon Dioxide ◽  
Soil Temperature ◽  
Nutrient Supply ◽  
Interactive Effects ◽  
Mass Ratio ◽  
White Birch ◽  
Stem Biomass ◽  
Leaf Mass Ratio ◽  
High Nutrient ◽  
High Nutrient Supply

To investigate the interactive effects of soil temperature (Tsoil) and nutrient supply on the responses of growth and biomass of white birch ( Betula papyrifera Marsh.) to atmospheric carbon dioxide concentration ([CO2]), seedlings were grown under two [CO2] (360 and 720 µmol·mol–1), three Tsoil (5, 15, and 25 °C initially, increased to 7, 17, and 27 °C one month later), and three nutrient regimes (Low: N–P–K = 4:1.8:3.3 mg·L–1; Intermediate: N–P–K = 80:35:66 mg·L–1; and High: N–P–K = 160:70:132 mg·L–1) for 4 months. Low Tsoil reduced leaf and total biomass at high nutrient supply and root biomass at intermediate and high nutrient supply. There were significant three-factor interactive effects on root collar diameter (RCD), stem biomass, and leaf mass ratio. Low Tsoil reduced RCD at high nutrient supply and stem biomass at intermediate and high nutrient supply in elevated [CO2] while intermediate and high Tsoil enhanced them. Values of leaf mass ratio were lowest at low Tsoil and low nutrient supply in elevated [CO2]. The effect of Tsoil was generally insignificant at low nutrient supply, but the responses of growth and biomass remained significantly higher under high than low nutrient supply at all Tsoil.

scholarly journals Export production fluctuations in the eastern equatorial Pacific during the Pliocene‐Pleistocene: Reconstruction using barite accumulation rates

2015 ◽  
Vol 30 (11) ◽  
pp. 1455-1469 ◽  
Author(s):  
Zhongwu Ma ◽  
Ana Christina Ravelo ◽  
Zhonghui Liu ◽  
Liping Zhou ◽  
Adina Paytan
Keyword(s):  
Equatorial Pacific ◽  
Accumulation Rates ◽  
Export Production ◽  
Eastern Equatorial Pacific
Sign in / Sign up

Export Citation Format

Share Document