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Clague D.A.,Monterey Bay Aquarium Research Institute | Braga J.C.,University of Granada | Bassi D.,University of Ferrara | Fullagar P.D.,University of North Carolina at Chapel Hill | And 2 more authors.
Journal of Biogeography | Year: 2010

Aim: To determine if Kōko Seamount submerged below sea level before Kure Island and Pearl and Hermes Reef formed, resulting in a period in which there were no extant islands. A period with no islands would eliminate prior terrestrial and shallow marine biotas that could migrate from island to island and require a restart of colonization from distant shores to populate the younger islands of the Hawaiian volcanic chain. Location: Emperor Seamount Chain, north-central Pacific Ocean. Methods: We estimate subsidence rates for Kōko Seamount using ages determined from fossil large foraminifera and Sr-isotopes, and maximum depths using palaeodepth estimates based on coralline algae. These data are combined with palaeolatitude changes as the Pacific Plate moved northwards, sea level variations, and sea surface temperature variations at the seamount through time to reconstruct the time and causes of submergence. Results: Rounded carbonate clasts include three facies: zooxanthelate corals, bioclastic packstones to rudstones, and rhodolith floatstones. Two rudstones contain relatively deep-water, coralline algal rhodoliths and large foraminifera indicative of Aquitanian (20.4-20 Ma) and Burdigalian (20-16 Ma) stages of the Early Miocene, consistent with Sr-isotope ages of algae and one sample of large foraminifera. Corals grew on Kōko Seamount from c. 50 to 27.1 ± 0.4 Ma, the youngest Sr-isotope age of a coral sample. These shallow, warm-water coral reefs came under increasing stress as the volcano subsided at 0.012 ± 0.003 mm yr-1, and migrated northwards, and as global climate cooled. The summit submerged and shallow coral reef growth ceased before 29 Ma, probably around 33 Ma. The volcano continued its slow subsidence, and deep-water carbonates accumulated until they too were unable to keep pace, dying out at c. 16 Ma. Main conclusions: The final submergence of the summit of Kōko Seamount by about 33 Ma confirms that biota on older Hawaiian-Emperor Islands could not have migrated from island to island along the entire chain to eventually colonize the present Hawaiian Islands. There was a period between at least 33 and 29 Ma in which no islands existed, and distant colonization had to repopulate the younger portion of the Hawaiian chain, which began to emerge between about 29 and 23 Ma. © 2009 Blackwell Publishing Ltd.


Tager D.,University of Queensland | Webster J.M.,University of Sydney | Potts D.C.,University of California at Santa Cruz | Renema W.,Nationaal Natuurhistorisch Museum | And 3 more authors.
Ecology | Year: 2010

Reef ecosystems built during successive periods of Pleistocene sea level rise have shown remarkable persistence in coral community structure, but little is known of the ecological characteristics of reef communities during periods of low sea stands or sea level falls. We sampled the relative species abundance of coral, benthic foraminifera, and calcareous red algae communities from eight submerged coral reefs in the Huon Gulf, Papua New Guinea, which formed during successive sea level fall and lowstand periods over the past -416 kyr. We found that dissimilarity in coral species composition increased significantly with increasing time between reef-building events. However, neither coral diversity nor the taxonomic composition of benthic foraminifera and calcareous red algae assemblages varied significantly over time. The taxonomie composition of coral communities from lowstand reefs was significantly different from that of highstand reefs previously reported from the nearby Huon Peninsula. We interpret the community composition and temporal dynamics of lowstand reefs as a result of shifting energy regimes in the Huon Gulf, and differences between low and highstand reefs as a result of differences in the interaction between biotic and environmental factors between the Huon Gulf and Huon Peninsula. Regardless of the exact processes driving these trends, our study represents the first glimpse into the ecological dynamics of coral reefs during low sea level stands when climatic conditions for reef growth were much different and less optimal than during previously studied highstand periods. © 2010 by the Ecological Society of America.


Faichney I.D.E.,James Cook University | Webster J.M.,James Cook University | Webster J.M.,University of Sydney | Clague D.A.,Monterey Bay Aquarium Research Institute | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2011

The submarine reef terraces (L1-L12) of the Maui Nui Complex (MNC-the islands of Lanai, Molokai, Maui and Kahoolawe) in Hawaii provide a unique opportunity to investigate the impact of climate and sea level change on coral reef growth by examining changes in reef development through the Mid-Pleistocene Transition (900-800. ka). We present an analysis of the biological and sedimentary composition of the reefs that builds directly on recently published chronological and morphological data. We define nine distinct limestone facies and place them in a spatial and stratigraphic context within 12 reef terraces using ROV and submersible observations. These include oolitic, two coral reef, two coralline algal nodule, algal crust, hemi-pelagic mud, bioclastic and peloidal mud facies. These facies characterise environments from high energy shallow water coral reef crests to low energy non-reefal deep-water settings. Combining the bottom observations and sedimentary facies data, we report a shift in the observed sedimentary facies across the submerged reefs of the MNC from dominant shallow coral reef facies on the deep reefs to coralline algae dominated exposed outcrop morphology on the shallower reefs. We argue that this shift is a reflection of the change in period and amplitude of glacioeustatic sea level cycles (41. kyr and 60-70. m to 100. kyr and 120. m) during the Mid-Pleistocene Transition (MPT, ~. 800. ka), coupled with a slowing in the subsidence rate of the complex. The growth of stratigraphically thick coral reef units on the deep Pre-MPT reefs was due to the rapid subsidence of the substrate and the shorter, smaller amplitude sea level cycles allowing re-occupation and coral growth on successive cycle low-stands. Longer, larger amplitude sea level cycles after the MPT combined with greater vertical stability at this time produced conditions conducive to deep-water coralline algae growth which veneered the shallower terraces. Additionally, we compare reef development both within the MNC, and between the MNC and Hawaii. Finally we suggest that climatic forcings such as sea-surface temperature and oceanographic currents may also have influenced the distribution of coral species within the sample suite, e.g., the disappearance of the Acropora genus from the Maui Nui Complex in the Middle Pleistocene. © 2010 Elsevier B.V.


Wei S.-J.,Zhejiang University | Wei S.-J.,Beijing Academy of Agriculture and Forestry Sciences | Shi M.,Zhejiang University | Sharkey M.J.,University of Kentucky | And 2 more authors.
BMC Genomics | Year: 2010

Background: Animal mitochondrial genomes are potential models for molecular evolution and markers for phylogenetic and population studies. Previous research has shown interesting features in hymenopteran mitochondrial genomes. Here, we conducted a comparative study of mitochondrial genomes of the family Braconidae, one of the largest families of Hymenoptera, and assessed the utility of mitochondrial genomic data for phylogenetic inference at three different hierarchical levels, i.e., Braconidae, Hymenoptera, and Holometabola.Results: Seven mitochondrial genomes from seven subfamilies of Braconidae were sequenced. Three of the four sequenced A+T-rich regions are shown to be inverted. Furthermore, all species showed reversal of strand asymmetry, suggesting that inversion of the A+T-rich region might be a synapomorphy of the Braconidae. Gene rearrangement events occurred in all braconid species, but gene rearrangement rates were not taxonomically correlated. Most rearranged genes were tRNAs, except those of Cotesia vestalis, in which 13 protein-coding genes and 14 tRNA genes changed positions or/and directions through three kinds of gene rearrangement events. Remote inversion is posited to be the result of two independent recombination events. Evolutionary rates were lower in species of the cyclostome group than those of noncyclostomes. Phylogenetic analyses based on complete mitochondrial genomes and secondary structure of rrnS supported a sister-group relationship between Aphidiinae and cyclostomes. Many well accepted relationships within Hymenoptera, such as paraphyly of Symphyta and Evaniomorpha, a sister-group relationship between Orussoidea and Apocrita, and monophyly of Proctotrupomorpha, Ichneumonoidea and Aculeata were robustly confirmed. New hypotheses, such as a sister-group relationship between Evanioidea and Aculeata, were generated. Among holometabolous insects, Hymenoptera was shown to be the sister to all other orders. Mecoptera was recovered as the sister-group of Diptera. Neuropterida (Neuroptera + Megaloptera), and a sister-group relationship with (Diptera + Mecoptera) were supported across all analyses.Conclusions: Our comparative studies indicate that mitochondrial genomes are a useful phylogenetic tool at the ordinal level within Holometabola, at the superfamily within Hymenoptera and at the subfamily level within Braconidae. Variation at all of these hierarchical levels suggests that the utility of mitochondrial genomes is likely to be a valuable tool for systematics in other groups of arthropods. © 2010 Wei et al; licensee BioMed Central Ltd.


Wei S.-J.,Zhejiang University | Wei S.-J.,Beijing Academy of Agriculture and Forestry Sciences | Shi M.,Zhejiang University | Chen X.-X.,Zhejiang University | And 4 more authors.
PLoS ONE | Year: 2010

Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and replication orientation/gene direction. The results show that the sign of GC skew on entire mitochondrial genomes is reversed in all species of three distantly related families of insects, Philopteridae (Phthiraptera), Aleyrodidae (Hemiptera) and Braconidae (Hymenoptera); the replication-related elements in the A+T-rich regions of these species are inverted, confirming that reversal of strand asymmetry (GC skew) was caused by inversion of replication origin; and finally, the sign of GC skew value is associated with replication orientation but not with gene direction, while that of AT skew value varies with gene direction, replication and codon positions used in analyses. These findings show that deaminations during replication and other mutations contribute more than selection on amino acid sequences to strand compositions of G and C, and that the replication process has a stronger affect on A and T content than does transcription. Our results may contribute to genome-wide studies of replication and transcription mechanisms. © 2010 Wei et al.


Hearty P.J.,University of North Carolina at Wilmington | Webster J.M.,University of Sydney | Clague D.A.,Moss Landing Marine Laboratories | Kaufman D.S.,Northern Arizona University | And 3 more authors.
Marine Geology | Year: 2010

We describe the first recorded occurrence of oolite in the main Hawaiian Islands. Well-cemented oolite was recovered at several locations at - 140 to - 150 m depth south of Lana'i. The ooids contain foraminiferal, skeletal, and peloidal nuclei, coated by thin to moderately thick (20-50% of ooid radius) tangential cortices, and are cemented by fibrous aragonite needles. The extent of amino acid racemization (AAR) analysed on 127 ooid grains and 55 pristine foraminifera in the same deposits confirm that the particles formed during a brief interval estimated at 1900 yr duration. A single, large benthic foraminiferan (Amphisorus sp.) intermixed with the ooid grains yielded a calibrated 14C age of 12.2 ± 0.3 ka. In contrast, a series of progressive leaches on two splits of ooid grains yielded a sequence of 14C ages ranging from ∼ 27 ka for the nuclei to < 15 ka from the outermost cortices, similar to recently reported results of deeply submerged ooids from the Great Barrier Reef (GBR), Australia. In contrast, a similar leach experiment using AAR showed no evidence for this 12,000-year range of apparent ages within the ooids. Based on modern analogues, individual ooids are unlikely to have formed continuously during 12 ka of deep submergence without leaving evidence of corrosion or bioerosion. At this time, we have no definitive explanation for the range 14C leach ages, and further research is needed. However, assuming that the age of the ooids lies between the 14C ages of the youngest cortex (14.9 ka) and the Amphisorus (12.2 ka), then eustatic sea-level history records suggest two intervals of slowing sea-level history rise that could accommodate ooid formation. These occurred immediately preceding MWP1A (∼ 15 ka) and MWP1B (∼ 12.5 ka). In the area of the oolite deposit, there is no terrace or hardground morphology that coincides with a - 100 m sea stand preceding MWP1A. Thus, we suggest that conditions required for ooid formation converged when a flat carbonate hardground in the broad Au'au Channel was initially flooded with energetic shallow water as sea level rose to and slowed at - 60 to - 55 m during the onset of the Younger Dryas (YD) interval around 12.7 ka. Ooid formation ensued for a short period (∼ 1900 yr) and then abruptly ceased; most reasonably as a result of a 7.5 m deepening of the sea during MWP1B around 11.5 ka. The oolitic sediments were subsequently transported longshore and offshore to southern Lana'i. © 2009 Elsevier B.V. All rights reserved.


Zhang N.-X.,Ocean University of China | Tang X.-L.,Ocean University of China | Van Ofwegen L.,Nationaal Natuurhistorisch Museum | Xue L.,Ocean University of China | And 3 more authors.
Chemistry and Biodiversity | Year: 2015

Four new polyhydroxylated steroids, 1-4, and the racemic form of cyclopentenone 9, together with four known steroids, 5-8, one known cyclopentenone derivative, 10, and one known butenolide derivative, 11, were isolated from the soft coral Sinularia acuta collected from Weizhou Island of Guangxi Province, P. R. China. Their structures were elucidated on the basis of spectroscopic analyses and by comparison of the corresponding data with those previously reported. The cytotoxicities of the isolates 1-11 in vitro against the selected tumor cell lines HL-60, HeLa, and K562 were evaluated. Compounds 2 and 5 showed potent cytotoxicities against HL-60 cell lines with IC50 values of 7.3 and 9.9 μM, respectively. Compounds 5 and 6 showed moderate activities against K562 cell lines with IC50 values of 10.9 and 11.7 μM, respectively, while compounds 1, 2, and 6 showed weak activities against HeLa cell lines with respective IC50 values of 44.8, 27.1, and 18.2 μM. This is the first report on chemical and bioactivity research of S. acuta. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.


Agis J.A.,University of Vigo | Vervoort W.,Nationaal Natuurhistorisch Museum | Ramil F.,University of Vigo
Zoosystema | Year: 2014

This publication is the third in a series of accounts on large collections of Plumularioidea McCrady, 1859 (Cnidaria, Hydrozoa, Hydroidolina) obtained during several French expeditions to the Philippines region, Vanuatu, New Caledonia, Fiji, and the Marquesas Islands. Additional material from Mozambique was also examined and is discussed. A total of 17 species, belonging to the families Kirchenpaueriidae Stechow, 1921 (two species) and Plumulariidae McCrady, 1859 (15 species), are scrutinized and illustrated in the present report. Three new species of the genus Plumularia Lamarck, 1816 are described (Plumularia bathyale n. sp., Plumularia contraria n. sp., Plumularia pseudocontraria n. sp.). The name Plumularia milsteinae n. nom., is proposed for Plumularia spiralis Milstein 1976, a permanently invalid junior homonym of Plumularia spiralis Billard, 1911. Polyplumaria kossowskae (Billard, 1911) is recorded for the first time since its original description. Two species of Plumularia are identified only to the genus level. Type materials of Plumularia habereri Stechow, 1909 and Dentitheca hertwigi Stechow, 1909, and the syntypes of all varieties of Plumularia habereri described by Billard (1913), have also been examined. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.


Snijders N.,Nationaal Natuurhistorisch Museum | Fransen C.H.J.M.,Nationaal Natuurhistorisch Museum
Zootaxa | Year: 2010

During a study of the associated fauna of gorgonians and black corals on the reefs of Curaçao (Netherlands Antilles, Caribbean Sea) by the first author, a new species of Pseudopontonides Heard, 1986: P. plumosus sp. nov. was discovered, which is here described and figured. Copyright © 2010 Magnolia Press.

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