Nitrogen isotope evidence for expanded ocean suboxia in the early Cenozoic

Science ◽  
2019 ◽  
Vol 364 (6438) ◽  
pp. 386-389 ◽  
Author(s):  
Emma R. Kast ◽  
Daniel A. Stolper ◽  
Alexandra Auderset ◽  
John A. Higgins ◽  
Haojia Ren ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Nitrogen Isotope ◽  
Tethys Sea ◽  
The North ◽  
Continental Shelves ◽  
Global Cooling ◽  
Isotope Evidence ◽  
Depth Water ◽  
The North Pacific ◽  
Early Cenozoic

The million-year variability of the marine nitrogen cycle is poorly understood. Before 57 million years (Ma) ago, the 15N/14N ratio (δ15N) of foraminifera shell-bound organic matter from three sediment cores was high, indicating expanded water column suboxia and denitrification. Between 57 and 50 Ma ago, δ15N declined by 13 to 16 per mil in the North Pacific and by 3 to 8 per mil in the Atlantic. The decline preceded global cooling and appears to have coincided with the early stages of the Asia-India collision. Warm, salty intermediate-depth water forming along the Tethys Sea margins may have caused the expanded suboxia, ending with the collision. From 50 to 35 Ma ago, δ15N was lower than modern values, suggesting widespread sedimentary denitrification on broad continental shelves. δ15N rose at 35 Ma ago, as ice sheets grew, sea level fell, and continental shelves narrowed.

Sinking organic matter spreads the nitrogen isotope signal of pelagic denitrification in the North Pacific

2009 ◽  
Vol 36 (8) ◽  
Author(s):  
Daniel M. Sigman ◽  
Peter J. DiFiore ◽  
Mathis P. Hain ◽  
Curtis Deutsch ◽  
David M. Karl
Keyword(s):  
Organic Matter ◽  
North Pacific ◽  
Nitrogen Isotope ◽  
The North ◽  
The North Pacific

Deep‐Water Formation in the North Pacific During the Late Miocene Global Cooling

2021 ◽  
Vol 36 (2) ◽  
Author(s):  
Lina Zhai ◽  
Shiming Wan ◽  
Christophe Colin ◽  
Debo Zhao ◽  
Yuntao Ye ◽  
...  
Keyword(s):  
Deep Water ◽  
Late Miocene ◽  
North Pacific ◽  
Deep Water Formation ◽  
The North ◽  
Global Cooling ◽  
Water Formation ◽  
The North Pacific

Cephalopods as prey. III. Cetaceans

1996 ◽  
Vol 351 (1343) ◽  
pp. 1053-1065 ◽  
Keyword(s):  
Polar Regions ◽  
Oceanic Water ◽  
Cetacean Species ◽  
Commercial Fish ◽  
Cephalopod Species ◽  
The North ◽  
Continental Shelf Water ◽  
Continental Shelves ◽  
Regional Estimates ◽  
The North Pacific

Over 80 % of odontocete species and two balaen whale species include cephalopods in their diet regularly. In 28 odontocetes they comprise the main food. Predominently cephalopod-eating species are found in the Physeteridae, Ziphiidae, Phocaenidae and Delphinidae. By far the most important of the 28 families of cephalopods represented in the diet of cetaceans are the oceanic Ommastrephidae, Histioteuthidae and the Cranchiidae, with the neritic Loliginidae assuming most importance on the continental shelves. Onychoteuthidae and Gonatidae assume greater importance in polar regions and the North Pacific. The other 22 families form a reservoir from which various cetaceans eat opportunistically and as their sizes permit. There are probably less than 60 cephalopod species regularly in the diet of cetaceans. Species composition of the food varies regionally, seasonally and annually. Locally, the greatest difference is found between cetaceans that live in oceanic water and continental shelf water. There is a positive correlation between the size of the prey and both the size of pelagic feeding cetacean species and the growth stage within a species. This leads to some partitioning of the food and less competition. Broad estimates show that the biomass of oceanic cephalopods consumed annually by the largest odontocete, Physeter catodon , may be over twice the biomass of fish caught by man. Regional estimates show that consumption by cetaceans of little known cephalopod species may greatly exceed the local catches of commercial fish.

scholarly journals Quaternary radiolarian biostratigraphy in the subarctic northeastern Pacific (IODP Expedition 341 Site U1417) and synchroneity of bioevents across the North Pacific

2018 ◽  
Vol 37 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Kenji M. Matsuzaki ◽  
Noritoshi Suzuki
Keyword(s):  
North Pacific ◽  
Sediment Cores ◽  
Gulf Of Alaska ◽  
Northwestern Pacific ◽  
Time Interval ◽  
The North ◽  
Integrated Ocean Drilling Program ◽  
Northeastern Pacific ◽  
Radiolarian Biostratigraphy ◽  
The North Pacific

Abstract. Expedition 341 of the Integrated Ocean Drilling Program (IODP) retrieved sediment cores spanning the time interval between the Pleistocene and Miocene from the southern Gulf of Alaska. Onboard Pleistocene radiolarian biostratigraphy is hereby refined by increasing the sampling resolution. The 178 core samples from the upper 190 m CCSF-B (Composite Core Depth Scale F-B) of Site U1417 contained faunal elements similar to the northwestern Pacific; for example, the three biozones in the northwestern Pacific (i.e., Eucyrtidium matuyamai, Stylatractus universus and Botryostrobus aquilonaris) were also recognized in the Gulf of Alaska, spanning 1.80–1.13 Ma, 1.13–0.45 Ma, and the last 0.45 Myr, respectively. Based on the age model that we used in this study and the shipboard paleomagnetic reversal events, the first occurrences (FOs) of Amphimelissa setosa and Schizodiscus japonicus in the northeastern Pacific were preliminarily determined to be 1.48 and 1.30 Ma, respectively. The last occurrence (LO) of Eucyrtidium matuyamai and the FO of Lychnocanoma sakaii, both well-established bioevents in the northwestern Pacific, were dated at 0.80 and 1.13 Ma, respectively. The LO of E. matuyamai is a synchronous event at 1.05 ± 0.1 Ma in the North Pacific, while the FOs of A. setosa and S. japonicus at 1.48 and 1.30 Ma, respectively, are significantly older than what has been found elsewhere.

scholarly journals A database of paleoceanographic sediment cores from the North Pacific, 1951–2016

2017 ◽  
Author(s):  
Marisa Borreggine ◽  
Sarah E. Myhre ◽  
K. Allison S. Mislan ◽  
Curtis Deutsch ◽  
Catherine V. Davis
Keyword(s):  
North Pacific ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Model Development ◽  
Data Set ◽  
Sedimentary Sequences ◽  
The North ◽  
The Pacific ◽  
Age Model ◽  
The North Pacific

Abstract. We assessed sediment coring, data acquisition, and publications from the North Pacific (north of 30˚ N) from 1951–2016. There are 2134 sediment cores collected by American, French, Japanese, Russian, and international research vessels across the North Pacific (including the Pacific Subarctic Gyre, Alaskan Gyre, Japan Margin, and California Margin, 1391 cores), Sea of Okhotsk (271 cores), Bering Sea (123 cores), and Sea of Japan (349 cores) reported here. All existing metadata associated with these sediment cores are documented, including coring date, location, core number, cruise number, water depth, vessel metadata, and coring technology. North Pacific age models are based on isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithophysical proxies. Here, we evaluate the iterative generation of each published age model and provide documentation of each dating technique used, as well as sedimentation rates and age ranges. We categorized cores according to availability of a variety of proxy evidence, including biological (e.g. benthic and planktonic foraminifera assemblages), geochemical (e.g. heavy metal concentrations), isotopic (e.g. bulk sediment nitrogen and carbon isotopes), and stratigraphic (e.g. preserved laminations) proxies. This database is a unique resource to the paleoceanographic and paleoclimate communities, and provides cohesive accessibility to sedimentary sequences, age model development, and proxies. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.875998.

scholarly journals A database of paleoceanographic sediment cores from the North Pacific, 1951–2016

2017 ◽  
Vol 9 (2) ◽  
pp. 739-749 ◽  
Author(s):  
Marisa Borreggine ◽  
Sarah E. Myhre ◽  
K. Allison S. Mislan ◽  
Curtis Deutsch ◽  
Catherine V. Davis
Keyword(s):  
North Pacific ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Model Development ◽  
The Sea Of Japan ◽  
Data Set ◽  
Sedimentary Sequences ◽  
The North ◽  
Age Model ◽  
The North Pacific

Abstract. We assessed sediment coring, data acquisition, and publications from the North Pacific (north of 30° N) from 1951 to 2016. There are 2134 sediment cores collected by American, French, Japanese, Russian, and international research vessels across the North Pacific (including the Pacific subarctic gyre, Alaskan gyre, Japan margin, and California margin; 1391 cores), the Sea of Okhotsk (271 cores), the Bering Sea (123 cores), and the Sea of Japan (349 cores) reported here. All existing metadata associated with these sediment cores are documented here, including coring date, location, core number, cruise number, water depth, vessel metadata, and coring technology. North Pacific sediment core age models are built with isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithological proxies. Here, we evaluate the iterative generation of each published age model and provide comprehensive documentation of the dating techniques used, along with sedimentation rates and age ranges. We categorized cores according to the availability of a variety of proxy evidence, including biological (e.g., benthic and planktonic foraminifera assemblages), geochemical (e.g., major trace element concentrations), isotopic (e.g., bulk sediment nitrogen, oxygen, and carbon isotopes), and stratigraphic (e.g., preserved laminations) proxies. This database is a unique resource to the paleoceanographic and paleoclimate communities and provides cohesive accessibility to sedimentary sequences, age model development, and proxies. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.875998.

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