scholarly journals An analysis of the sessile, structure-forming invertebrates living on California oil and gas platforms

2019 ◽  
Vol 95 (4) ◽  
pp. 583-596
Author(s):  
Milton S Love ◽  
Mary M Nishimoto ◽  
Linda Snook ◽  
Li Kui
Keyword(s):  
Southern California ◽  
Oil And Gas ◽  
Narrow Range ◽  
Depth Range ◽  
Lophelia Pertusa ◽  
The Family ◽  
Species Groups ◽  
Invertebrate Assemblages

Using video transects of oil and gas platform crossbeams off central and southern California, we characterized the structure-forming invertebrates (with a height of at least 20 cm) found around 23 oil and gas platforms at depths between 20 and 363 m. We observed 20,357 individual invertebrates, comprising 19,800 Cnidaria and 557 Porifera of at least 15 species or species groups. Metridium farcimen (Brandt, 1835) was by far the most commonly observed cnidarian, forming 97.6% of all invertebrates catalogued. The alcyonacean, Leptogorgia chilensis (Verrill, 1868), and the scleractinian, Lophelia pertusa (Linnaeus, 1758), were the most commonly observed corals. White vase sponges (most or all in the family Aphrocallistidae) were the most abundant of the sponges (comprising 38.4% observed). We also documented a variety of unidentified foliose, barrel, and other various-shaped sponges. The height of these invertebrates ranged from 20 to 80 cm. Taxa displayed a variety of depth patterns. Some, such as M. farcimen, unidentified white vase sponges, and L. pertusa, were found throughout most or all of the survey depth range, while others (notably the gorgonians L. chilensis, Placogorgia spp., and Acanthogorgia spp.) were found over a relatively narrow range. Invertebrate assemblages tended to be similar among many platforms reflecting species similarities over a broad range of platform depths. Based on these relationships, it is apparent that the assemblages of structure-forming invertebrates varied by depth rather than geography.

Feeding Habits of Alepocephalus Rostratus (Pisces: Alepocephalidae) in the Western Mediterranean Sea

1998 ◽  
Vol 78 (4) ◽  
pp. 1295-1306 ◽  
Author(s):  
M. Carrassón ◽  
J. Matallanas
Keyword(s):  
Mediterranean Sea ◽  
Prey Item ◽  
Narrow Range ◽  
Feeding Habits ◽  
Western Mediterranean ◽  
Western Mediterranean Sea ◽  
The Family ◽  
Different Seasons ◽  
Scarcity Of Resources ◽  
Important Fish

The present study examines the feeding habits of Alepocephalus rostratus, the only species of the family Alepocephalidae in the Mediterranean Sea and the second most important fish species, in terms of biomass, inhabiting the deep slope of the Catalan Sea. Samples were obtained at depths between 1000–2250 m. Diet was analysed for two different size-classes (immature and mature specimens) at three different bathymetric strata during two different seasons. The feeding habits of A. rostratus included a narrow range of mobile macroplanktonic organisms (e.g. Pyrosoma atlanticum and Chelophyes appendiculata) and some material of benthic origin. Pyrosoma atlanticum was the preferred prey item in spring at 1000–1425 m, being very scarce in summer at the same depth as a consequence of its scarcity in the environment during this season. There were some ontogenic differences in the diet of A. rostratus at 1425–2250 m. Adults ingested more and larger prey than juvenile specimens. The scarcity of resources below 1200–1400 m fostered a more diversified diet, as well as passive predation of sedimented material.

Two new species of stalked crinoids from the northeastern Pacific in the genera Gephyrocrinus and Ptilocrinus (Echinodermata, Crinoidea, Hyocrinidae). Effects of ontogeny and variability on hyocrinid taxonomy

Zootaxa ◽  
2011 ◽  
Vol 2825 (1) ◽  
pp. 1 ◽  
Author(s):  
MICHEL ROUX ◽  
PHILIP LAMBERT
Keyword(s):  
British Columbia ◽  
New Species ◽  
Single Species ◽  
Depth Range ◽  
Evolutionary Trend ◽  
Exceptional Collection ◽  
The Family ◽  
Two New Species ◽  
Northeastern Pacific ◽  
Stalked Crinoids

Two new species of deep-sea stalked crinoids belonging to the family Hyocrinidae were collected in the northeastern Pacific. The descriptions contain detailed information on character variations and ontogeny. The five specimens of Gephyrocrinus messingi n. sp. lived at depths ranging from 1,777 m to 2,110 m off British Columbia and California. This new species is the first record of the genus Gephyrocrinus in the Pacific Ocean, which was previously known from only a single species, G. grimaldii, from the northeastern Atlantic at the same depth range. The two species illustrate opposing phenotypes within the same genus. Fifty-eight specimens of the second new species, Ptilocrinus clarki n. sp., were dredged off British Columbia close to the type-locality of P. pinnatus, the type species of the genus Ptilocrinus, but at shallower depths ranging from 1,178 to 1,986 m. This exceptional collection provides significant data on intraspecific variation in the main morphological characters, especially arm pattern. The ontogeny of stalk articulations and the main traits of adoral plate differentiation are described in detail. A complementary investigation on P. pinnatus was conducted using specimens collected by the “Albatross” expedition at a depth of 2,906 m. Despite similarities in external morphology, tegmen and cover plates, the two ptilocrinid species display significant differences in pinnule architecture, aboral cup and stalk articulations. From comparison with Gephyrocrinus messingi n. sp. and Ptilocrinus clarki n. sp., G. grimaldii and P. pinnatus are interpreted as the result of heterochronic development by paedomorphy after ecological or geographic isolation. Pinnule architecture in the two new species suggests first steps in an evolutionary trend toward a rigid box which protects gonad inflation in the proximal part of the pinnule. These new data on Ptilocrinus and Gephyrocrinus create problems in the current taxonomy of the family Hyocrinidae. The main derived characters, especially in pinnule and arm pattern, are used to propose new hypotheses for hyocrinid phylogeny.

scholarly journals Phylogenetic partitioning of the third-largest vertebrate genus in the world, Cyrtodactylus Gray, 1827 (Reptilia; Squamata; Gekkonidae) and its relevance to taxonomy and conservation

2021 ◽  
Vol 71 ◽  
pp. 101-154 ◽  
Author(s):  
L. Lee Grismer ◽  
Perry L. Wood, Jr. ◽  
Nikolay A. Poyarkov ◽  
Minh D. Le ◽  
Fred Kraus ◽  
...  
Keyword(s):  
Conservation Management ◽  
Narrow Range ◽  
Small Islands ◽  
Rate Data ◽  
Ecological Studies ◽  
The Third ◽  
True Number ◽  
The World ◽  
Species Groups ◽  
Mitochondrial Phylogeny

The gekkonid genus Cyrtodactylus is the third most speciose vertebrate genus in the world, containing well over 300 species that collectively range from South Asia to Melanesia across some of the most diverse landscapes and imperiled habitats on the planet. A genus-wide phylogeny of the group has never been presented because researchers working on different groups were using different genetic markers to construct phylogenies that could not be integrated. We present here Maximum likelihood and Bayesian inference mitochondrial and mito-nuclear phylogenies incorporating of 310 species that include dozens of species that had never been included in a genus-wide analysis. Based on the mitochondrial phylogeny, we partition Cyrtodactylus into 31 well-supported monophyletic species groups which, if used as recommended herein, will increase the information content of future integrative taxonomic analyses that continue to add new species to this genus at an ever-increasing annual rate. Data presented here reiterate the outcome of several previous studies indicating that Cyrtodactylus comprises an unprecedented number of narrow-range endemics restricted to single mountain tops, small islands, or karst formations that still remain unprotected. This phylogeny can provide a platform for various comparative ecological studies that can be integrated with conservation management programs across the broad diversity of landscapes and habitats occupied by this genus. Additionally, these data indicate that the true number of Cyrtodactylus remains substantially underrepresented.

scholarly journals Exceptional new fossil of Siphonophrentis gigantea

2018 ◽  
Author(s):  
Christian R McCall
Keyword(s):  
Cold Water ◽  
Lophelia Pertusa ◽  
Stony Corals ◽  
Rugose Corals ◽  
Sea Bed ◽  
The Family ◽  
Water Coral

Rugose Corals, often referred to as Horn Coral, are an extinct order of stony corals in the phylum Cnidaria. They lived from the Ordivician period to the end of the Permian period, and can be found worldwide. A new fossil of Siphonophrentis gigantea, a species of Rugosa in the family Streptelasmatidae, has been recovered from the Devonian strata of the Lucas Formation. The fossil gives clues towards the paleobiology of Siphonophrentis, revealing it to have likely anchored itself to the sea bed in the ocean depths. Siphonophrentis gigantea likely had no relationship with Zooxanthellae, a kind of Dinoflagellate that gives modern extant coral their colour and allows them to photosynthesize. These single celled organisms appear to be absent in Siphonophrentis, and it instead received nutrients from a rich amount of biological debris that fell into its habitat. Further comparisons can be made between Siphonophrentis and the extant, cold-water coral Lophelia pertusa.

scholarly journals A Comparison of Fishes and Invertebrates Living in the Vicinity of Energized and Unenergized Submarine Power Cables and Natural Sea Floor off Southern California, USA

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Milton S. Love ◽  
Mary M. Nishimoto ◽  
Linda Snook ◽  
Donna M. Schroeder ◽  
Ann Scarborough Bull
Keyword(s):  
Southern California ◽  
Statistical Difference ◽  
Fish Assemblages ◽  
Natural Habitat ◽  
Habitat Type ◽  
Aquatic Organisms ◽  
Power Cables ◽  
Sea Floor ◽  
Total Fish ◽  
Species Groups

Increasing reliance on deep-water renewable energy has increased concerns about the effects of the electromagnetic fields (EMFs) generated by submarine power cables on aquatic organisms. Off southern California, we conducted surveys of marine organisms living around energized and unenergized submarine power cables and nearby sea floor during 2012–2014 at depths between 76 and 213 m. In general, EMFs declined to background levels about one meter from the cable. We found no statistical difference in species composition between the fish assemblages along the energized and unenergized cables. The natural habitat community statistically differed from both energized and unenergized cable communities. Within species (or species groups), we found no differences in densities between energized and unenergized cables. Total fish densities were significantly higher around the cables than over the natural habitat. We found that invertebrate communities were structured by habitat type and depth and, similar to the fishes, there was no statistical difference between the energized and unenergized cables. Individually, the densities of four invertebrate species or species groups (Metridium farcimen, Luidia spp., unidentified black Crinoidea, and Urticina spp.) differed between energized and unenergized cables, but this difference was not significant across all depth strata. The invertebrate community inhabiting the natural habitat strongly differed from the energized and unenergized cable community exhibiting the fewest species and individuals.

scholarly journals Fish densities associated with structural elements of oil and gas platforms in southern California

2019 ◽  
Vol 95 (4) ◽  
pp. 639-656 ◽  
Author(s):  
Erin L Meyer-Gutbrod ◽  
Li Kui ◽  
Mary M Nishimoto ◽  
Milton S Love ◽  
Donna M Schroeder ◽  
...  
Keyword(s):  
Habitat Use ◽  
Southern California ◽  
Oil And Gas ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Artificial Reef ◽  
Offshore Structures ◽  
Structural Elements ◽  
Structural Element ◽  
Young Of The Year

There are thousands of offshore oil and gas platforms worldwide that will eventually become obsolete, and one popular decommissioning alternative is the "rigs to reefs" conversion that designates all or a portion of the underwater infrastructure as an artificial reef, thereby reducing the burden of infrastructure removal. The unique architecture of each platform may influence the size and structure of the associated fish assemblage if different structural elements form distinct habitats for fishes. Using scuba survey data from 11 southern California platforms from 1995 to 2000, we examined fish assemblages associated with structural elements of the structure, including the major horizontal crossbeams outside of the jacket, vertical jacket legs, and horizontal crossbeams that span the jacket interior. Patterns of habitat association were examined among three depth zones: shallow (<16.8 m), midwater (16.8–26 m), and deep (>26 m); and between two life stages: young- of-the-year and non-young-of-the-year. Fish densities tended to be greatest along horizontal beams spanning the jacket interior, relative to either horizontal or vertical beams along the jacket exterior, indicating that the position of the habitat within the overall structure is an important characteristic affecting fish habitat use. Fish densities were also higher in transects centered directly over a vertical or horizontal beam relative to transects that did not contain a structural element. These results contribute to the understanding of fish habitat use on existing artificial reefs, and can inform platform decommissioning decisions as well as the design of new offshore structures intended to increase fish production.

Systematics of reptile-associated scale mites of the genus Pterygosoma (Acariformes: Pterygosomatidae) derived from external morphology

Zootaxa ◽  
2019 ◽  
Vol 4603 (3) ◽  
pp. 401
Author(s):  
MONIKA FAJFER
Keyword(s):  
North Africa ◽  
New Genus ◽  
Arabian Peninsula ◽  
Morphological Characters ◽  
Mite Species ◽  
South American ◽  
The Family ◽  
Outgroup Species ◽  
Tree Lizards ◽  
Species Groups

The phylogeny of the mite genus Pterygosoma Peters, 1849 (Acariformes: Pterygosomatidae), permanent parasites of lizards of the families Agamidae, Gerrhosauridae and Liolaemidae (Reptilia: Squamata), was inferred with maximum parsimony, successive weighting and implied weighting approaches based on 182 characters of 48 ingroup and 12 outgroup species. All undertaken analyses questioned the monophyly of the genus. Based on this research, Pterygosoma includes 56 mite species associated with agamas from Africa and Asia (Sauria: Agamidae). Within the genus seven natural species groups were found: mutabilis, inermis, melanum, caucasica, fimbriata, singularis and foliosetis; 13 species of the genus were not assigned to any of the groups due to their unique morphological characters. For the ligare group of the subgenus Pterygosoma s. str. (7 species) associated with the South American tree lizards from the family Liolaemidae, a new genus, Neopterygosoma gen. nov., is established. The subgenus Gerrhosaurobia Lawrence, 1959 (3 species) associated with the African plated lizards of the family Gerrhosauridae is elevated to the genus rank. Diagnoses for the three genera are presented. Historical associations are reconstructed by fitting the obtained mite tree into the host topology on the family level. Results of coevolutionary analysis highlight the coincidence of both trees. The studies suggest that the ancestor of the genus Pterygosoma switched from the hosts of Gerrhosaurobia i.e. from the plated lizards (Gerrhosauridae) to the agamas (Agamidae), and the genus Pterygosoma has its biogeographic origin in North Africa, and colonized Asia via the Arabian Peninsula, which is congruent with the historical biogeography of its hosts.

Wave Propagation Versus Transient Ground Displacement as a Credible Hazard to Buried Oil and Gas Pipelines

2000 ◽  
Author(s):  
Douglas G. Honegger
Keyword(s):  
Wave Propagation ◽  
Southern California ◽  
Oil And Gas ◽  
Ground Deformation ◽  
Gas Pipeline ◽  
Tensile Failure ◽  
Northridge Earthquake ◽  
Research Activity ◽  
Research Project ◽  
Permanent Ground Deformation

In 1997, a research project was initiated by Southern California Gas Company, Pacific Gas and Electric Company, with support from Tokyo Gas, Osaka Gas, and Toho Gas, to investigate the cause of natural gas pipeline damage during the 1994 Northridge earthquake. As part of this research activity, extensive field and laboratory investigations were performed on a 1925 gas pipeline that suffered several girth weld failures in Potrero Canyon, a remote and unpopulated area just north of the Santa Susana Mountains. The pipeline is operated by the Southern California Gas Company, one of the principle sponsors of the gas utility research project. The investigations into the performance of the pipeline were largely prompted by questions regarding the cause of pipeline damage. Although ground cracking and sand boils were observed in Potrero Canyon following the Northridge earthquake, there were no clear signs of permanent ground deformation near the locations of pipeline damage. Pipeline damage, consisting predominantly of girth weld tensile failure and two instances of buckling of the pipe wall, indicated that significant relative pipe-soil deformation might have occurred. Field investigations were unable to identify surface evidence of permanent ground deformation near the locations of pipeline damage and attention focused on the possibility that the damage could have been caused by wave propagation. This focus was based on the assertions of past researchers that pipelines with poor-quality oxyacetylene girth welds are susceptible to damage from wave propagation. The detailed investigation of The pipeline has concluded that wave propagation was not a significant factor in the pipeline damage and raises questions regarding wave propagation effects as a causative mechanism for pipeline damage in past earthquakes. A simple analytical model of the transient ground deformation that may have occurred in the vicinity of the pipeline damage was found to provide insight into the cause of the ground cracking observed at the margins of Potrero Canyon, approximate magnitudes of differential ground displacements that may have occurred during the earthquake, and the reasons for the spatial distribution of pipeline damage. This model is proposed as the basis for identifying locations where similar earthquake effects can be identified in future hazard assessment studies.

Taxonomic review of the genus Meleonoma Meyrick (Lepidoptera: Autostichidae), with a checklist of all the described species

Zootaxa ◽  
2020 ◽  
Vol 4763 (3) ◽  
pp. 371-393 ◽  
Author(s):  
SHUXIA WANG ◽  
XIAOJU ZHU ◽  
BAIXUE ZHAO ◽  
XIAOFEI YANG
Keyword(s):  
Morphological Study ◽  
Molecular Data ◽  
Species Group ◽  
Diagnostic Characters ◽  
Taxonomic Review ◽  
The Family ◽  
Species Groups

Meleonoma Meyrick, 1914 is treated as a genus of the family Autostichidae based on the recent study. Fifty species are transferred from the genus Cryptolechia to Meleonoma, and eight Meleonoma species groups are proposed for the taxonomic convenience based on both molecular data and morphological study. Eight species groups include: the malacobyrsa group, the segregnatha group, the annulignatha group, the fasciptera group, the jigongshanica group, the dentivalvata group, the facialis group, and the acutiuscula group. Diagnostic characters and representative illustrations of each species group are provided. A discussion on the proposed species groups is given, and a checklist of all the 88 described Meleonoma species is provided. 

Triaina, a new genus in the Janirellidae Menzies, 1956 (Crustacea: Isopoda: Asellota), with two new species from south-eastern Australia, and a new diagnosis for the family

Zootaxa ◽  
2009 ◽  
Vol 1980 (1) ◽  
pp. 1-15 ◽  
Author(s):  
JEAN JUST
Keyword(s):  
New Species ◽  
New Genus ◽  
Depth Range ◽  
Diverse Range ◽  
South Eastern ◽  
Eastern Australia ◽  
The Family ◽  
Two New Species ◽  
New Diagnosis ◽  
South Eastern Australia

The varying concepts of Janirellidae Menzies, 1956 are outlined, including its rejection by several authors. The view of Wilson and Wägele of Janirellidae being a valid family comprising Janirella Bonnier, 1896 and presumably Dactylostylis Richardson, 1911 (= Spinianirella Menzies, 1962) is accepted. Diagnoses of the Janirellidae subsequent to Menzies’ original one were based on the inclusion of a diverse range of genera now recognised as not belonging in that family. A new diagnosis of Janirellidae is presented based on the inclusion of Janirella, Dactylostylis, and a new genus Triaina with two new species, T. isodonte and T. makridonte, from south-eastern Australia. The latter species represents the shallowest record (80 m) of the otherwise predominantly deep-water family. All species in the family are listed in an appendix, with area of type locality and depth range.

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