scholarly journals Multiple melt source origin of the Line Islands (Pacific Ocean)

Geology ◽  
2021 ◽  
Author(s):  
Robert Pockalny ◽  
Ginger Barth ◽  
Barry Eakins ◽  
Katherine A. Kelley ◽  
Christina Wertman
Keyword(s):  
Pacific Ocean ◽  
Source Region ◽  
Central Pacific ◽  
Age Progression ◽  
Central Pacific Ocean ◽  
Volcanic Chain ◽  
History Of ◽  
Tectonic Reconstructions ◽  
Seamount Chain ◽  
Line Islands

The Line Islands volcanic chain in the central Pacific Ocean exhibits many characteristics of a hotspot-generated seamount chain; however, the lack of a predictable age progression has stymied previous models for the origin of this feature. We combined plate-tectonic reconstructions with seamount age dates and available geochemistry to develop a new model that involves multiple melt regions and multiple melt delivery styles to explain the spatial and temporal history of the Line Islands system. Our model identifies a new melt source region (Larson melt region at ~17°S, ~125°W) that contributed to the formation of the Line Islands, as well as the Mid-Pacific Mountains and possibly the Pukapuka Ridge.

scholarly journals Understanding large-scale, long-term larval connectivity patterns: The case of the Northern Line Islands in the Central Pacific Ocean

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0182681
Author(s):  
Lorenzo Mari ◽  
Luca Bonaventura ◽  
Andrea Storto ◽  
Paco Melià ◽  
Marino Gatto ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Large Scale ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Larval Connectivity ◽  
Connectivity Patterns ◽  
Line Islands

scholarly journals Johnston Atoll: Reef Fish Hybrid Zone between Hawaii and the Equatorial Pacific

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 83
Author(s):  
Phillip S. Lobel ◽  
Lisa K. Lobel ◽  
John E. Randall
Keyword(s):  
Pacific Ocean ◽  
Reef Fish ◽  
Local Population ◽  
Fish Population ◽  
Equatorial Pacific ◽  
Ocean Current ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Wide Range ◽  
Line Islands

Johnston Atoll is isolated in the Central Pacific Ocean (16°45′ N 169°31′ W) about 1287 km (800 miles) southwest of Honolulu, Hawaii and 1440 km (900 miles) north of the equatorial Line Islands, Kiribati. The labrid species, Thalassoma lutescens, has a wide range of distribution in the equatorial Pacific. The related species, Thalassoma duperrey, is endemic to the Hawaiian Islands. The pelagic larvae of both species dispersed to Johnston Atoll, where we found a mix of adult phenotypes representing a range of hybridization events over generations. A hybrid acanthurid was also documented. In addition, the arrival and colonization of two pomacentrid (damselfish) species to the atoll was observed in 1999. These pomacentrid sister-species, Abudefduf abdominalis and A. vaigiensis, have become established populations with subsequent hybridization. The biogeography of the Johnston Atoll coral reef fish population shows some degree of local population retention. It is also evident that this biogeographic isolation is periodically compromised by large ocean current oscillations in the equatorial and central Pacific Ocean that bring larval fishes from either Hawaii or the Line Islands, and may distribute Johnston Atoll originating larvae elsewhere as well. The reef fauna and oceanography of this atoll provides the circumstances for improving scientific insight into marine fish speciation and island biogeography.

scholarly journals The Recent Carbonate Sediments of Palmyra Atoll, Northern Line Islands, Central Pacific Ocean

2021 ◽  
Author(s):  
◽  
Oscar Clark
Keyword(s):  
Pacific Ocean ◽  
Carbonate Sediments ◽  
Central Pacific ◽  
Outer Reef ◽  
Central Pacific Ocean ◽  
Fine Material ◽  
The Pacific ◽  
Red Algal ◽  
Recent Sediments ◽  
Line Islands

<p>Palmyra Atoll is an isolated carbonate reef system located approximately 1600 km south of Hawaii in the northern Line Islands, central Pacific Ocean. Sediment samples from the lagoons and tidal zones were analyzed for grainsize and composition, and the results used to compile detailed maps and interpret the environments and lithofacies present. A distinct grainsize distribution was observed forming concentric bands ranging from coarse gravel rubble on the outer reef through to finer material in the interior of the atoll in the deep lagoons, where peloidal muds prevail. Five lithologic facies have been identified and typical sediments are poorly sorted and near-symmetrical in their grainsize distribution. On average, sediments are medium sand. A distinct chlorozoan assemblage was observed with coral and calcareous red algal fragments forming half of the sediment, with varying amounts of molluscs, Halimeda and foraminifera being the lesser major constituents. Lagoonal and tidal sediments showed little variation in composition between locations and lacked clear compositional zonation, characteristic of other larger atolls of the Pacific. Palmyra Atoll is unique in that it has had little human intervention for the last sixty years and as a result uninhibited natural processes are occurring. It is also unique in that it displays relatively deep for its size (<55 m), steep-sided compartmentalized lagoons that have abundant fine material (upward of 70% silt or finer), a feature not commonly observed at other Pacific atolls. This fine material has been identified as a peloidal mud and its mode and rate of deposition may be partly controlled by the abundant zooplankton in the lagoons. Recent sediments of Palmyra Atoll are almost entirely carbonate, originating from reef organisms inhabiting the atoll. The only other material is small amounts of siliceous sponge skeletons.</p>

scholarly journals The Recent Carbonate Sediments of Palmyra Atoll, Northern Line Islands, Central Pacific Ocean

2021 ◽  
Author(s):  
◽  
Oscar Clark
Keyword(s):  
Pacific Ocean ◽  
Carbonate Sediments ◽  
Central Pacific ◽  
Outer Reef ◽  
Central Pacific Ocean ◽  
Fine Material ◽  
The Pacific ◽  
Red Algal ◽  
Recent Sediments ◽  
Line Islands

<p>Palmyra Atoll is an isolated carbonate reef system located approximately 1600 km south of Hawaii in the northern Line Islands, central Pacific Ocean. Sediment samples from the lagoons and tidal zones were analyzed for grainsize and composition, and the results used to compile detailed maps and interpret the environments and lithofacies present. A distinct grainsize distribution was observed forming concentric bands ranging from coarse gravel rubble on the outer reef through to finer material in the interior of the atoll in the deep lagoons, where peloidal muds prevail. Five lithologic facies have been identified and typical sediments are poorly sorted and near-symmetrical in their grainsize distribution. On average, sediments are medium sand. A distinct chlorozoan assemblage was observed with coral and calcareous red algal fragments forming half of the sediment, with varying amounts of molluscs, Halimeda and foraminifera being the lesser major constituents. Lagoonal and tidal sediments showed little variation in composition between locations and lacked clear compositional zonation, characteristic of other larger atolls of the Pacific. Palmyra Atoll is unique in that it has had little human intervention for the last sixty years and as a result uninhibited natural processes are occurring. It is also unique in that it displays relatively deep for its size (<55 m), steep-sided compartmentalized lagoons that have abundant fine material (upward of 70% silt or finer), a feature not commonly observed at other Pacific atolls. This fine material has been identified as a peloidal mud and its mode and rate of deposition may be partly controlled by the abundant zooplankton in the lagoons. Recent sediments of Palmyra Atoll are almost entirely carbonate, originating from reef organisms inhabiting the atoll. The only other material is small amounts of siliceous sponge skeletons.</p>

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.

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