Octocoral Mitochondrial Genomes Provide Insights into the Phylogenetic History of Gene Order Rearrangements, Order Reversals, and Cnidarian Phylogenetics

We use full mitochondrial genomes to test the robustness of the phylogeny of the Octocorallia, to determine the evolutionary pathway for the five known mitochondrial gene rearrangements in octocorals, and to test the suitability of using mitochondrial genomes for higher taxonomic-level phylogenetic reconstructions. Our phylogeny supports three major divisions within the Octocorallia and show that Paragorgiidae is paraphyletic, with Sibogagorgia forming a sister branch to the Coralliidae. Furthermore, Sibogagorgia cauliflora has what is presumed to be the ancestral gene order in octocorals, but the presence of a pair of inverted repeat sequences suggest that this gene order was not conserved but rather evolved back to this apparent ancestral state. Based on this we recommend the resurrection of the family Sibogagorgiidae to fix the paraphyly of the Paragorgiidae. This is the first study to show that in the Octocorallia, mitochondrial gene orders have evolved back to an ancestral state after going through a gene rearrangement, with at least one of the gene orders evolving independently in different lineages. A number of studies have used gene boundaries to determine the type of mitochondrial gene arrangement present. However, our findings suggest that this method known as gene junction screening may miss evolutionary reversals. Additionally, substitution saturation analysis demonstrates that while whole mitochondrial genomes can be used effectively for phylogenetic analyses within Octocorallia, their utility at higher taxonomic levels within Cnidaria is inadequate. Therefore for phylogenetic reconstruction at taxonomic levels higher than subclass within the Cnidaria, nuclear genes will be required, even when whole mitochondrial genomes are available

Reproductive morphology of three species of deep-water precious corals from the Hawaiian Archipelago : Gerardia Sp., Corallium secundum, and Corallium lauuense

Author Posting. © University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2007. This article is posted here by permission of University of Miami - Rosenstiel School of Marine and Atmospheric Science for personal use, not for redistribution. The definitive version was published in Bulletin of Marine Science 81 (2007): 533-542.Three species of deep-sea corals were collected from several locations in the Hawaiian Archipelago. These species have been called "precious corals" because of their extensive use in the jewelry industry. Two octocorals Corallium lauuense Bayer, 1956 (red coral) and Corallium secundum Dana, 1846 (pink coral), and a zoanthid, Gerardia sp. (gold coral) collected between August and November in 1998-2004, were all histologically analysed for reproductive tissues. All three species of precious corals appear to be gonochoric (both males and females of all species being identified—though with C. lauuense more reproductive polyps are needed to conclusively confirm this), with the two species of Corallium having reproductive material contained within siphonozooids rather than the main polyp (autozoid). Maximum oocyte sizes were: Gerardia sp. ∼300 μm, C. secundum ∼600 μm, and C. lauuense ∼660 μm. All three species are hypothesized to have spawned during the collection season. Gerardia was observed spawning during collection, and histological sections of the two Corallium species show areas where gametes appear to be missing. Gerardia sp. has a single cohort of gametes developing, which may suggest seasonal reproduction, and the two Corallium species show multiple sizes present in single individuals, suggesting a periodic or quasi-continuous reproductive periodicity.This project was supported by ship time grants from the Hawaii Undersea Research Laboratory and Hawaii SeaGrant as well as National Oceanic and Atmospheric Administration’s Office of Ocean Exploration Award No. NA03OAR4600108. A.R.B. received support from an EPA STAR graduate research fellowship and a Woods Hole Oceanographic Institution postdoctoral scholarship

Diversity of Zoanthids (Anthozoa: Hexacorallia) on Hawaiian Seamounts: Description of the Hawaiian Gold Coral and Additional Zoanthids

The Hawaiian gold coral has a history of exploitation from the deep slopes and seamounts of the Hawaiian Islands as one of the precious corals commercialised in the jewellery industry. Due to its peculiar characteristic of building a scleroproteic skeleton, this zoanthid has been referred as Gerardia sp. (a junior synonym of Savalia Nardo, 1844) but never formally described or examined by taxonomists despite its commercial interest. While collection of Hawaiian gold coral is now regulated, globally seamounts habitats are increasingly threatened by a variety of anthropogenic impacts. However, impact assessment studies and conservation measures cannot be taken without consistent knowledge of the biodiversity of such environments. Recently, multiple samples of octocoral-associated zoanthids were collected from the deep slopes of the islands and seamounts of the Hawaiian Archipelago. The molecular and morphological examination of these zoanthids revealed the presence of at least five different species including the gold coral. Among these only the gold coral appeared to create its own skeleton, two other species are simply using the octocoral as substrate, and the situation is not clear for the final two species. Phylogenetically, all these species appear related to zoanthids of the genus Savalia as well as to the octocoral-associated zoanthid Corallizoanthus tsukaharai, suggesting a common ancestor to all octocoral-associated zoanthids. The diversity of zoanthids described or observed during this study is comparable to levels of diversity found in shallow water tropical coral reefs. Such unexpected species diversity is symptomatic of the lack of biological exploration and taxonomic studies of the diversity of seamount hexacorals

Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century

Ongoing greenhouse gas emissions can modify climate processes and induce shifts in ocean temperature, pH, oxygen concentration, and productivity, which in turn could alter biological and social systems. Here, we provide a synoptic global assessment of the simultaneous changes in future ocean biogeochemical variables over marine biota and their broader implications for people. We analyzed modern Earth System Models forced by greenhouse gas concentration pathways until 2100 and showed that the entire world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. In contrast, only a small fraction of the world's ocean surface, mostly in polar regions, will experience increased oxygenation and productivity, while almost nowhere will there be ocean cooling or pH elevation. We compiled the global distribution of 32 marine habitats and biodiversity hotspots and found that they would all experience simultaneous exposure to changes in multiple biogeochemical variables. This superposition highlights the high risk for synergistic ecosystem responses, the suite of physiological adaptations needed to cope with future climate change, and the potential for reorganization of global biodiversity patterns. If co-occurring biogeochemical changes influence the delivery of ocean goods and services, then they could also have a considerable effect on human welfare. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by simultaneous changes in ocean biogeochemistry. These results highlight the high risk of degradation of marine ecosystems and associated human hardship expected in a future following current trends in anthropogenic greenhouse gas emissions

Observation of a high abundance aggregation of the deep-sea urchin Chaetodiadema pallidum A. Agassiz and H.L. Clark, 1907 on the Northwestern Hawaiian Island Mokumanamana

AUV images of deep-sea megafauna on the seamount Mokumanamana in the Northwestern Hawaiian Islands revealed a large aggregation of the diadematoid urchin Chaetodiadema pallidum. This species had not been previously recorded on this seamount, but was known from other locations in the Hawaiian Archipelago. A total of 11,360 individuals were counted by eye from 1,369 seafloor images along the 200, 250, and 300 m depth contours on the west side of Mokumanamana. To estimate the full population size, Inverse Distance Weighting and Empirical Bayesian Kriging interpolation calculated a total population size of between 139,552 and 144,063 individuals. These estimates are 1-2 orders of magnitude greater than any previous estimates of urchin aggregation abundances. Little biological data exists for this species; thus, it is difficult to know if this is a spawning aggregation, a feeding front, a type of "schooling" behavior, or some combination thereof, but a food source did seem to be present in the form of mesophotic green algal detritus

Depth distribution of <i>Narella</i> combination haplotypes sorted by minimum depth of occurrence.

<p>Combination haplotypes, as designated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045555#pone-0045555-t001" target="_blank">Table 1</a>, are given in the columns, along with the first three letters of the species name. 100 m depth bins are provided in the rows. Dark blue indicate an actual depth for a given haplotype, light blue indicates possible range for Haplotype 3 and is used to fill in the depth range for other columns. Numbers indicate number of individuals in a given depth range with that haplotype when the value is greater than 1. ? - indicates mean of possible range of depths for specimens for which depth was not recorded.</p

Summary statistics for each marker.

<p>Sequence length indicates final length of the alignment after the ends were trimmed and unalignable gaps were removed as outlined in the text. “Resolved” refers to the species for which all observed haplotypes for a species for the given marker were unique to that species. Distances are given as uncorrected “p” distances, with the number of base changes the distance values correspond to given in the subsequent line.</p

Geographic distribution of combination haplotypes found in Alaskan waters.

<p>A. Distribution for combination haplotypes that occur on Derickson Seamount. No combination haplotypes on Derickson were shared with the GOA Seamounts, overlap with Hawaii is shown. Satellite imagery: GoogleEarth. Date accessed: 05 Jan 2011. Co-ordinates: approx. 18–58°N, 168°E to 150°W. B. Geographic distribution of combination haplotypes found in the Gulf of Alaska. Numbers within a circle indicate number of individuals with that haplotype when greater than 1 for a feature. Satellite imagery: GoogleEarth. Date accessed: 05 Jan 2011. Co-ordinates: approx. 52° to 59°30<i>′</i>N, 153°50<i>′</i> to 143°20<i>′</i>W.</p

Collection information for the specimens used in this study.

<p>USNM# is the catalog number for the specimen at the Smithsonian Institution. Dive numbers are abbreviated by vehicle – AD- Alvin Dive, P5– Pisces 5, T – Tiburon, JD – Jason II Dive. Haplotypes for each marker are number coded, with each number indicating a unique sequence for a given marker. Variable positions among haplotypes of Narella for each marker are given in Supplemental <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045555#pone-0045555-t002" target="_blank">Table 2</a>.</p><p>‘– specimen depth not recorded, values given are for depth range for dive, or specimens collected before and after that individual.</p>*<p>indicates a specimens which was sequenced more than once, with identical sequences encountered every time.</p