scholarly journals Mercury isotopes identify near-surface marine mercury in deep-sea trench biota

2020 ◽  
Vol 117 (47) ◽  
pp. 29292-29298 ◽  
Author(s):  
Joel D. Blum ◽  
Jeffrey C. Drazen ◽  
Marcus W. Johnson ◽  
Brian N. Popp ◽  
Laura C. Motta ◽  
...  
Keyword(s):  
Deep Sea ◽  
Methyl Mercury ◽  
Photochemical Degradation ◽  
Central Pacific ◽  
Mariana Trench ◽  
Near Surface ◽  
Average Value ◽  
Central Pacific Ocean ◽  
Mercury In Fish ◽  
Mass Dependent

Mercury isotopic compositions of amphipods and snailfish from deep-sea trenches reveal information on the sources and transformations of mercury in the deep oceans. Evidence for methyl-mercury subjected to photochemical degradation in the photic zone is provided by odd-mass independent isotope values (Δ199Hg) in amphipods from the Kermadec Trench, which average 1.57‰ (±0.14,n= 12, SD), and amphipods from the Mariana Trench, which average 1.49‰ (±0.28,n= 13). These values are close to the average value of 1.48‰ (±0.34,n= 10) for methyl-mercury in fish that feed at ∼500-m depth in the central Pacific Ocean. Evidence for variable contributions of mercury from rainfall is provided by even-mass independent isotope values (Δ200Hg) in amphipods that average 0.03‰ (±0.02,n= 12) for the Kermadec and 0.07‰ (±0.01,n= 13) for the Mariana Trench compared to the rainfall average of 0.13 (±0.05,n= 8) in the central Pacific. Mass-dependent isotope values (δ202Hg) are elevated in amphipods from the Kermadec Trench (0.91 ±0.22‰,n= 12) compared to the Mariana Trench (0.26 ±0.23‰,n= 13), suggesting a higher level of microbial demethylation of the methyl-mercury pool before incorporation into the base of the foodweb. Our study suggests that mercury in the marine foodweb at ∼500 m, which is predominantly anthropogenic, is transported to deep-sea trenches primarily in carrion, and then incorporated into hadal (6,000-11,000-m) food webs. Anthropogenic Hg added to the surface ocean is, therefore, expected to be rapidly transported to the deepest reaches of the oceans.

scholarly journals Primary Production in the Water Column as Major Structuring Element of the Biogeographical Distribution and Function of Archaea in Deep-Sea Sediments of the Central Pacific Ocean

Archaea ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Franziska Wemheuer ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Marion Pohlner ◽  
Julius Degenhardt ◽  
Bert Engelen ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Deep Sea ◽  
Archaeal Community ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Deep Sea Sediments ◽  
And Function ◽  
Functional Profiles ◽  
Archaeal Communities

Information on environmental conditions shaping archaeal communities thriving at the seafloor of the central Pacific Ocean is limited. The present study was conducted to investigate the diversity, composition, and function of both entire and potentially active archaeal communities within Pacific deep-sea sediments. For this purpose, sediment samples were taken along the 180° meridian of the central Pacific Ocean. Community composition and diversity were assessed by Illumina tag sequencing targeting archaeal 16S rRNA genes and transcripts. Archaeal communities were dominated by CandidatusNitrosopumilus(Thaumarchaeota) and other members of theNitrosopumilaceae(Thaumarchaeota), but higher relative abundances of the Marine Group II (Euryarchaeota) were observed in the active compared to the entire archaeal community. The composition of the entire and the active archaeal communities was strongly linked to primary production (chlorophyll content), explaining more than 40% of the variance. Furthermore, we found a strong correlation of the entire archaeal community composition to latitude and silicic acid content, while the active community was significantly correlated with primary production and ferric oxide content. We predicted functional profiles from 16S rRNA data to assess archaeal community functions. Latitude was significantly correlated with functional profiles of the entire community, whereas those of the active community were significantly correlated with nitrate and chlorophyll content. The results of the present study provide first insights into benthic archaeal communities in the Pacific Ocean and environmental conditions shaping their diversity, distribution, and function. Additionally, they might serve as a template for further studies investigating archaea colonizing deep-sea sediments.

scholarly journals New species of Eurythenes from hadal depths of the Mariana Trench, Pacific Ocean (Crustacea: Amphipoda)

Zootaxa ◽  
2020 ◽  
Vol 4748 (1) ◽  
pp. 163-181 ◽  
Author(s):  
JOHANNA N. J. WESTON ◽  
PRISCILLA CARRILLO-BARRAGAN ◽  
THOMAS D. LINLEY ◽  
WILLIAM D. K. REID ◽  
ALAN J. JAMIESON
Keyword(s):  
Pacific Ocean ◽  
Morphological Characteristics ◽  
Anthropogenic Pollution ◽  
Ocean Basin ◽  
Northwest Pacific ◽  
Central Pacific ◽  
Bathymetric Range ◽  
Northwest Pacific Ocean ◽  
Mariana Trench ◽  
Central Pacific Ocean

Eurythenes S. I. Smith in Scudder, 1882 are one of the largest scavenging deep-sea amphipods (max. 154 mm) and are found in every ocean across an extensive bathymetric range from the shallow polar waters to hadal depths. Recent systematic studies of the genus have illuminated a cryptic species complex and highlighted the benefits of using a combination of morphological and molecular identification approaches. In this study, we present the ninth species, Eurythenes plasticus sp. nov., which was recovered using baited traps between the depths 6010 and 6949 m in the Mariana Trench (Northwest Pacific Ocean) in 2014. This new Eurythenes species was found to have distinct morphological characteristics and be a well-supported clade based on sequence variation at two mitochondrial regions (16S rDNA and COI). While this species is new to science and lives in the remote hadal zone, it is not exempt from the impacts of anthropogenic pollution. Indeed, one individual was found to have a microplastic fibre, 83.74% similar to polyethylene terephthalate (PET), in its hindgut. As this species has a bathymetric range spanning from abyssal to hadal depths in the Central Pacific Ocean basin, it offers further insights into the biogeography of Eurythenes. 

scholarly journals Large Asian dust layers continuously reached North America in April 2010

2011 ◽  
Vol 11 (14) ◽  
pp. 7333-7341 ◽  
Author(s):  
I. Uno ◽  
K. Eguchi ◽  
K. Yumimoto ◽  
Z. Liu ◽  
Y. Hara ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
North America ◽  
Asian Dust ◽  
Northwestern China ◽  
Central Pacific ◽  
Pressure System ◽  
Near Surface ◽  
Dust Transport ◽  
Aerosol Model ◽  
Central Pacific Ocean

Abstract. The NASA space-borne Mie-lidar system CALIPSO/CALIOP revealed that multiple large Asian dust layers with a horizontal scale of 2000–3000 km reached North America, occupying the full troposphere, in April 2010. This kind of dust layer transport has not been reported before. Our analysis of CALIOP data and global aerosol model results revealed that frequent dust emissions occurred in northwestern China because of stronger-than-average near-surface winds, and that strong stable westerly winds carried the Asian dust from northwestern China to the central Pacific Ocean. A negative pressure anomaly was located in the eastern Pacific Ocean, and the main dust transport path was split into two branches: a northern path and a southern path over North America. Northern-path dust was trapped and stagnant for a longer time than southern path dust and finally subsided under a high-pressure system. Dust along the southern path reached the central US. These complex conditions resulted in a multi-layered structure of dust over North America.

scholarly journals Neanthes goodayi sp. nov. (Annelida, Nereididae), a remarkable new annelid species living inside deep-sea polymetallic nodules

2021 ◽  
Vol 760 ◽  
pp. 160-185
Author(s):  
Regan Drennan ◽  
Helena Wiklund ◽  
Muriel Rabone ◽  
Magdalena N. Georgieva ◽  
Thomas G. Dahlgren ◽  
...  
Keyword(s):  
Deep Sea ◽  
Mineral Exploration ◽  
Large Animal ◽  
Central Pacific ◽  
Suitable Candidate ◽  
Central Pacific Ocean ◽  
Polymetallic Nodules ◽  
Potential Indicator ◽  
Seabed Mining ◽  
A New Species

A new species of abyssal Neanthes Kinberg, 1865, N. goodayi sp. nov., is described from the Clarion-Clipperton Zone in the central Pacific Ocean, a region targeted for seabed mineral exploration for polymetallic nodules. It is a relatively large animal found living inside polymetallic nodules and in xenophyophores (giant Foraminifera) growing on nodules, highlighting the importance of the mineral resource itself as a distinct microhabitat. Neanthes goodayi sp. nov. can be distinguished from its congeners primarily by its distinctive, enlarged anterior pair of eyes in addition to characters of the head, pharynx and parapodia. Widespread, abundant, and easily recognisable, N. goodayi sp. nov. is also considered to be a suitable candidate as a potential indicator taxon for future monitoring of the impacts of seabed mining.

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