scholarly journals Early Paleogene variations in the calcite compensation depth: new constraints using old boreholes across Ninetyeast Ridge in the Indian Ocean

2014 ◽  
Vol 10 (4) ◽  
pp. 3163-3221
Author(s):  
B. S. Slotnick ◽  
V. Lauretano ◽  
J. Backman ◽  
G. R. Dickens ◽  
A. Sluijs ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Carbon Isotope ◽  
Deep Sea ◽  
Carbonate Content ◽  
Early Eocene ◽  
Ninetyeast Ridge ◽  
Scientific Drilling ◽  
Compensation Depth ◽  
The Indian Ocean ◽  
Early Paleogene

Abstract. Major variations in global carbon cycling occurred between 62 and 48 Ma. To better constrain the cause and magnitude of these changes, the community needs early Paleogene carbon isotope and carbonate accumulation records from widely separated deep-sea sediment sections, especially including the Indian Ocean. With the potential for renewed scientific drilling in the Indian Ocean, we examine lithologic, nannofossil assemblage, carbon isotope, and carbonate content records for late Paleocene – early Eocene sediment recovered at three existing sites spanning Ninetyeast Ridge: Deep Sea Drilling Project (DSDP) Sites 213 (deep, east), 214 (shallow, central), and 215 (deep, west). The sediment sections are not ideal, because they were recovered in single holes using rotary coring methods. Site 214 was very shallow during the late Paleocene, when it received significant amounts of neritic carbonate. The δ13C records at Sites 213 and 215 are similar to those generated at several locations in the Atlantic and Pacific. The prominent high in δ13C across the Paleocene carbon isotope maximum (PCIM) occurs at Site 215, and the prominent low in δ13C across the early Eocene Climatic Optimum (EECO) occurs at both Site 213 and Site 215. The Paleocene–Eocene thermal maximum (PETM) and the K/X event are found at Site 213 but not at Site 215, presumably because of coring gaps. Carbonate content at both Sites 213 and 215 drops to < 5% shortly after the first occurrence of Discoaster lodoensis and the early Eocene rise in δ13C (~ 52 Ma). This reflects a rapid shoaling of the calcite compensation depth (CCD), and likely a major decrease in the net flux of 13C-depleted carbon to the ocean. Our work further constrains knowledge of the early Paleogene CCD, but more importantly suggests that excellent early Paleogene carbonate accumulation records might be recovered from the central Indian Ocean with future scientific drilling.

scholarly journals Early Paleogene variations in the calcite compensation depth: new constraints using old borehole sediments from across Ninetyeast Ridge, central Indian Ocean

2015 ◽  
Vol 11 (3) ◽  
pp. 473-493 ◽  
Author(s):  
B. S. Slotnick ◽  
V. Lauretano ◽  
J. Backman ◽  
G. R. Dickens ◽  
A. Sluijs ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Carbon Isotope ◽  
Carbonate Content ◽  
Early Eocene ◽  
Ninetyeast Ridge ◽  
Scientific Drilling ◽  
Central Indian Ocean ◽  
Compensation Depth ◽  
The Indian Ocean ◽  
Early Paleogene

Abstract. Major variations in global carbon cycling occurred between 62 and 48 Ma, and these very likely related to changes in the total carbon inventory of the ocean-atmosphere system. Based on carbon cycle theory, variations in the mass of the ocean carbon should be reflected in contemporaneous global ocean carbonate accumulation on the seafloor and, thereby, the depth of the calcite compensation depth (CCD). To better constrain the cause and magnitude of these changes, the community needs early Paleogene carbon isotope and carbonate accumulation records from widely separated deep-sea sediment sections, especially including the Indian Ocean. Several CCD reconstructions for this time interval have been generated using scientific drill sites in the Atlantic and Pacific oceans; however, corresponding information from the Indian Ocean has been extremely limited. To assess the depth of the CCD and the potential for renewed scientific drilling of Paleogene sequences in the Indian Ocean, we examine lithologic, nannofossil, carbon isotope, and carbonate content records for late Paleocene – early Eocene sediments recovered at three sites spanning Ninetyeast Ridge: Deep Sea Drilling Project (DSDP) Sites 213 (deep, east), 214 (shallow, central), and 215 (deep, west). The disturbed, discontinuous sediment sections are not ideal, because they were recovered in single holes using rotary coring methods, but remain the best Paleogene sediments available from the central Indian Ocean. The δ13C records at Sites 213 and 215 are similar to those generated at several locations in the Atlantic and Pacific, including the prominent high in δ13C across the Paleocene carbon isotope maximum (PCIM) at Site 215, and the prominent low in δ13C across the early Eocene Climatic Optimum (EECO) at both Site 213 and Site 215. The Paleocene-Eocene thermal maximum (PETM) and the K/X event are found at Site 213 but not at Site 215, presumably because of coring gaps. Carbonate content at both Sites 213 and 215 drops to <5% shortly after the first occurrence of Discoaster lodoensis and the early Eocene rise in δ13C (~52 Ma). This reflects a rapid shoaling of the CCD, and likely a major decrease in the net flux of 13C-depleted carbon to the ocean. Our results support ideas that major changes in net fluxes of organic carbon to and from the exogenic carbon cycle occurred during the early Paleogene. Moreover, we conclude that excellent early Paleogene carbonate accumulation records might be recovered from the central Indian Ocean with future scientific drilling.

scholarly journals Pararhodobacter marinus sp. nov., isolated from deep-sea water of the Indian Ocean

2019 ◽  
Vol 69 (4) ◽  
pp. 932-936 ◽  
Author(s):  
Qiliang Lai ◽  
Xiupian Liu ◽  
Jun Yuan ◽  
Shuchen Xie ◽  
Zongze Shao
Keyword(s):  
Indian Ocean ◽  
Deep Sea ◽  
Type Species ◽  
Sea Water ◽  
Rrna Gene ◽  
Chromosomal Dna ◽  
Content Type ◽  
Deep Sea Water ◽  
Link Type ◽  
The Indian Ocean

A taxonomic study was carried out on strain CIC4N-9T, which was isolated from deep-sea water of the Indian Ocean. The bacterium was Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and non-motile. Growth was observed at salinities of 0–9% and at temperatures of 4–41 °C. The isolate was able to degrade gelatin but not aesculin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CIC4N-9T belonged to the genus Pararhodobacter , with the highest sequence similarity to the only recognized species, Pararhodobacter aggregans D1-19T (96.9 %). The average nucleotide identity and estimated DNA–DNA hybridization values between strain CIC4N-9T and P. aggregans D1-19T were 80.4 and 23.0 %, respectively. The principal fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0, C18 : 1ω7c 11-methyl, C18 : 0 and C17 : 0. The G+C content of the chromosomal DNA was 66.8 mol%. The sole respiratory quinone was determined to be Q-10. Phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, two unknown phospholipids, four unknown aminolipids and one unknown polar lipid were present. The combined genotypic and phenotypic data show that strain CIC4N-9T represents a novel species within the genus Pararhodobacter , for which the name Pararhodobacter marinus sp. nov. is proposed. The type strain is CIC4N-9T (=MCCC 1A01225T=KCTC 52336T).

New genera, species and occurrence records of Goniasteridae (Asteroidea; Echinodermata) from the Indian Ocean

Zootaxa ◽  
2018 ◽  
Vol 4539 (1) ◽  
pp. 1 ◽  
Author(s):  
CHRISTOPHER L. MAH
Keyword(s):  
Indian Ocean ◽  
Deep Sea ◽  
Western Indian Ocean ◽  
Gut Contents ◽  
New Genera ◽  
Late 20Th Century ◽  
The North ◽  
Marine Habitats ◽  
The Indian Ocean ◽  
Occurrence Records

Modern goniasterids are the most numerous of living asteroids in terms of described genera and species and they have important ecological roles from shallow to deep-water marine habitats. Recent MNHN expeditions and historical collections in the USNM have resulted in the discovery of 18 new species, three new genera and multiple new occurrence records from the western Indian Ocean region including Madagascar, Glorioso and Mayotte islands, Walters Shoal, South Africa, and Somalia. This report provides the first significant contribution to knowledge of deep-sea Asteroidea from the Indian Ocean since the late 20th Century. Several deep-sea species, previously known from the North Pacific are now reported from the western Indian Ocean. Gut contents from Stellaster and Ogmaster indicate deposit feeding. Feeding modes of this and other deep-sea species are discussed. Comments are made on fossil members of included taxa. A checklist of Indian Ocean Goniasteridae is also included.

Micro-forms of hay-silica glass and of volcanic glass

1968 ◽  
Vol 36 (283) ◽  
pp. 1012-1023 ◽  
Author(s):  
George Baker
Keyword(s):  
Indian Ocean ◽  
Deep Sea ◽  
Silica Glass ◽  
Volcanic Glass ◽  
Volcanic Eruptions ◽  
North West ◽  
South West ◽  
Deep Sea Sediments ◽  
The Indian Ocean ◽  
Lava Fountains

SummaryIn view of recently reported microtektites in deep-sea sediments north-west, south-west, and south of Australia, attention is drawn to the occurrence of minute forms of hay-silica glass among the products of incineration of opal-bearing vegetation in haystacks, and to the minute forms of volcanic glass ejected in lava fountains. These terrestrial micro-forms of glass have properties within the range of those for the fossil glassy bodies named ‘microtektites’. It is possible that the fusion of opal contained in silica-accumulator plants during fierce, prehistoric forest, bush, and grass fires in Australia generated micro-forms of glass that became readily airborne and drifted away in up-currents. Carried by the south-east Trades, they would ultimately descend over the Wharton Basin in the Indian Ocean. Strong to violent northerlies and north-easterlies (Brickfielder Winds) would carry them over the ocean south and south-west of Australia. Thus they could contribute to the deposits of bodies of glass regarded as microtektites in deep-sea sediments. Many microbodies of glass in the Wharton Basin could have had their origin in the Javanese volcanic eruptions.

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