scholarly journals Conditions and mechanism for the formation of iron-rich Montmorillonite in deep sea sediments (Costa Rica margin): Coupling high resolution mineralogical characterization and geochemical modeling

2011 ◽  
Vol 75 (6) ◽  
pp. 1397-1410 ◽  
Author(s):  
D. Charpentier ◽  
M.D. Buatier ◽  
E. Jacquot ◽  
A. Gaudin ◽  
C.G. Wheat
Keyword(s):  
Costa Rica ◽  
High Resolution ◽  
Deep Sea ◽  
Geochemical Modeling ◽  
Mineralogical Characterization ◽  
Deep Sea Sediments ◽  
Costa Rica Margin

scholarly journals Graphic correlation of deep sea and shallow marine deposits from the Central American Isthmus region: implications for Late Neogene paleoclimatology

1992 ◽  
Vol 6 ◽  
pp. 88-88
Author(s):  
Harry J. Dowsett
Keyword(s):  
Costa Rica ◽  
High Resolution ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Sea Surface ◽  
Central American ◽  
Major Barrier ◽  
Late Neogene ◽  
The Caribbean ◽  
Central American Isthmus

The stratigraphic record in Panama and Costa Rica preserves the biologic and climatic changes associated with the formation of a major barrier to marine migration and ocean circulation. Creating a high resolution temporal framework within which stratigraphic sections found on the Isthmus can be interpreted is fundamental to our understanding the history and importance of these units.The Isthmus contains rich marine macro- and microfaunas and floras on both the Pacific and Atlantic margins. Planktic foraminifers and calcareous nannofossils are common and often well preserved. Preliminary analysis of these fossils reveals a rich sedimentary record spanning the Late Miocene to Pleistocene. Multivariate statistical analyses of these assemblages provide environmental estimates. Unfortunately, traditional methods of biostratigraphy are limited in their ability to create a high resolution temporal framework for the region. For example, a majority of deposits analyzed can be placed in planktic foraminiferal zone N19 (early Pliocene). In order to answer paleobiologic and paleoclimatic questions one requires more precise correlations between sections and some indication of duration of sedimentation represented by various sections.In an attempt to overcome the shortcomings of traditional biostratigraphic methods, the Graphic Correlation method has been applied to selected sequences on the Central American Isthmus. Graphic correlation (GC) is a procedure by which two sequences can be compared and correlated using a wide variety of stratigraphic information simultaneously. A GC model of late Neogene planktic foraminifer, calcareous nannofossil, and paleomagnetic reversal events has been produced through compositing of more than 26 deep sea cores and ocean margin sequences. Following routine GC procedures the positions of all fossil first and last occurrences from a number of sections on the Caribbean and Pacific sides of the Central American Isthmus (Panama and Costa Rica) have been recorded. These sections have been correlated to the GC model and hence, to each other, providing a temporal framework for the Isthmus units.Selected sections were then correlated to other sequences such as near-by deep sea cores which have been analyzed for sea surface temperature and salinity to gain a better understanding of the overall paleoceanographic development of the region between 5 and 2 Ma. For example, correlation of units on the Caribbean side of the Isthmus with DSDP Site 502 indicates little to no change in sea surface temperatures during the entire time the Isthmus was reaching closure. Mid-to-high latitude sites exhibit amplification of warming with increasing latitude. The shoaling Isthmus, while having negligible effects on tropical marine temperatures, was responsible for increased meridional heat transport which resulted in a North Atlantic warming about 3 Ma. A general model for paleoceanographic changes during the time of closure will be discussed.

Characterization of deep sea sediments from the continental margin off Costa Rica

2016 ◽  
Vol 111 ◽  
pp. 13-21
Author(s):  
Joo Yong Lee ◽  
Gil Young Kim ◽  
Changho Lee ◽  
Jong-Sub Lee
Keyword(s):  
Costa Rica ◽  
Continental Margin ◽  
Deep Sea ◽  
Deep Sea Sediments

scholarly journals Helarchaeota and co-occurring sulfate-reducing bacteria in subseafloor sediments from the Costa Rica Margin

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Rui Zhao ◽  
Jennifer F. Biddle
Keyword(s):  
Costa Rica ◽  
Metabolic Pathways ◽  
Phylogenetic Analyses ◽  
Sulfate Reducing Bacteria ◽  
Sulfate Reducing ◽  
Hydrocarbon Emission ◽  
Costa Rica Margin ◽  
Reducing Bacteria ◽  
Electron Transfers ◽  
Deep Sediments

AbstractDeep sediments host many archaeal lineages, including the Asgard superphylum which contains lineages predicted to require syntrophic partnerships. Our knowledge about sedimentary archaeal diversity and their metabolic pathways and syntrophic partners is still very limited. We present here new genomes of Helarchaeota and the co-occurring sulfate-reducing bacteria (SRB) recovered from organic-rich sediments off Costa Rica Margin. Phylogenetic analyses revealed three new metagenome-assembled genomes (MAGs) affiliating with Helarchaeota, each of which has three variants of the methyl-CoM reductase-like (MCR-like) complex that may enable them to oxidize short-chain alkanes anaerobically. These Helarchaeota have no multi-heme cytochromes but have Group 3b and Group 3c [NiFe] hydrogenases, and formate dehydrogenase, and therefore have the capacity to transfer the reducing equivalents (in the forms of hydrogen and formate) generated from alkane oxidation to external partners. We also recovered five MAGs of SRB affiliated with the class of Desulfobacteria, two of which showed relative abundances (represented by genome coverages) positively correlated with those of the three Helarchaeota. Genome analysis suggested that these SRB bacteria have the capacity of H2 and formate utilization and could facilitate electron transfers from other organisms by means of these reduced substances. Their co-occurrence and metabolic features suggest that Helarchaeota may metabolize synergistically with some SRB, and together exert an important influence on the carbon cycle by mitigating the hydrocarbon emission from sediments to the overlying ocean.

scholarly journals Mechanism and Influencing Factors of REY Enrichment in Deep-Sea Sediments

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 196
Author(s):  
Jiangbo Ren ◽  
Yan Liu ◽  
Fenlian Wang ◽  
Gaowen He ◽  
Xiguang Deng ◽  
...  
Keyword(s):  
Deep Sea ◽  
Research Progress ◽  
Bottom Current ◽  
Knowledge Map ◽  
P2o5 Content ◽  
Deep Sea Sediments ◽  
Potential Resource ◽  
And Migration ◽  
Adsorption Desorption ◽  
Sediment Interface

Deep-sea sediments with high contents of rare-earth elements and yttrium (REY) are expected to serve as a potential resource for REY, which have recently been proved to be mainly contributed by phosphate component. Studies have shown that the carriers of REY in deep-sea sediments include aluminosilicate, Fe-Mn oxyhydroxides, and phosphate components. The ∑REY of the phosphate component is 1–2 orders of magnitude higher than those of the other two carriers, expressed as ∑REY = 0.001 × [Al2O3] − 0.002 × [MnO] + 0.056 × [P2O5] − 32. The sediment P2O5 content of 1.5% explains 89.1% of the total variance of the sediment ∑REY content. According to global data, P has a stronger positive correlation with ∑REY compared with Mn, Fe, Al, etc.; 45.5% of samples have a P2O5 content of less than 0.25%, and ∑REY of not higher than 400 ppm. The ∑REY of the phosphate component reaches n × 104 ppm, much higher than that of marine phosphorites and lower than that of REY-phosphate minerals, which are called REY-rich phosphates in this study. The results of microscopic observation and separation by grain size indicate that the REY-rich phosphate component is mainly composed of bioapatite. When ∑REY > 2000 ppm, the average CaO/P2O5 ratio of the samples is 1.55, indicating that the phosphate composition is between carbonate fluoroapatite and hydroxyfluorapatite. According to a knowledge map of sediment elements, the phosphate component is mainly composed of P, Ca, Sr, REY, Sc, U, and Th, and its chemical composition is relatively stable. The phosphate component has a negative Ce anomaly and positive Y anomaly, and a REY pattern similar to that of marine phosphorites and seawater. After the early diagenesis process (biogeochemistry, adsorption, desorption, transformation, and migration), the REY enrichment in the phosphate component is completed near the seawater/sediment interface. In the process of REY enrichment, the precipitation and enrichment of P is critical. According to current research progress, the REY enrichment is the result of comprehensive factors, including low sedimentation rate, high ∑REY of the bottom seawater, a non-carbonate depositional environment, oxidation conditions, and certain bottom current conditions.

The degradation activities for three seaweed polysaccharides of Shewanella sp. WPAGA9 isolated from deep‐sea sediments

2021 ◽  
Author(s):  
Dingquan Wang ◽  
Jianxin Wang ◽  
Runying Zeng ◽  
Jie Wu ◽  
Shijia V. Michael ◽  
...  
Keyword(s):  
Deep Sea ◽  
Deep Sea Sediments
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