Articles

Published journal articles by MLML faculty, staff and students. Full text is included when copyright allows.


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A mass stranding of sperm whales in Oregon
A mass stranding of sperm whales in Oregon
A school of 41 sperm whales, Physeter macrocephalus, that stranded near the mouth of the Siuslaw River, Oregon (43°59’N, 124°08’W), on 16 June 1979 consisted of 13 males and 28 females. Their ages were estimated by assuming that each postnatal dentin layer represents one year. The males were all subadults, 9.3-11.5 m long and 14-21 yr old. The females were 9.3-11.4 m long, and 11 to about 58 yr old. Ten females were dissected; nine were sexually mature and three were carrying fetuses 2.64-4.62 m long. None of the 28 females was visibly lactating.
A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean
A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean
The seeding of an expanse of surface waters in the equatorial Pacific Ocean with low concentrations of dissolved iron triggered a massive phytoplankton bloom which consumed large quantities of carbon dioxide and nitrate that these microscopic plants cannot fully utilize under natural conditions. These and other observations provide unequivocal support for the hypothesis that phytoplankton growth in this oceanic region is limited by iron bioavailability., Cited By (since 1996):930, Oceanography
A millennial-scale record of Pb and Hg contamination in peatlands of the Sacramento–San Joaquin Delta of California, USA
A millennial-scale record of Pb and Hg contamination in peatlands of the Sacramento–San Joaquin Delta of California, USA
In this paper, we provide the first record of millennial patterns of Pb and Hg concentrations on the west coast of the United States. Peat cores were collected from two micro-tidal marshes in the Sacramento–San Joaquin Delta of California. Core samples were analyzed for Pb, Hg, and Ti concentrations and dated using radiocarbon and 210Pb. Pre-anthropogenic concentrations of Pb and Hg in peat ranged from 0.60 to 13.0 μg g− 1and from 6.9 to 71 ng g− 1, respectively. For much of the past 6000 + years, the Delta was free from anthropogenic pollution, however, beginning in ~ 1425 CE, Hg and Pb concentrations, Pb/Ti ratios, Pb enrichment factors (EFs), and HgEFs all increased. Pb isotope compositions of the peat suggest that this uptick was likely caused by smelting activities originating in Asia. The next increases in Pb and Hg contamination occurred during the California Gold Rush (beginning ~ 1850 CE), when concentrations reached their highest levels (74 μg g− 1 Pb, 990 ng g− 1 Hg; PbEF = 12 and HgEF = 28). Lead concentrations increased again beginning in the ~ 1920s with the incorporation of Pb additives in gasoline. The phase-out of lead additives in the late 1980s was reflected in changes in Pb isotope ratios and reductions in Pb concentrations in the surface layers of the peat. The rise and subsequent fall of Hg contamination was also tracked by the peat archive, with the highest Hg concentrations occurring just before 1963 CE and then decreasing during the post-1963 period. Overall, the results show that the Delta was a pristine region for most of its ~ 6700-year existence; however, since ~ 1425 CE, it has received Pb and Hg contamination from both global and regional sources.
A model for estimating cross-shore surface transport with application to the New Jersey Shelf
A model for estimating cross-shore surface transport with application to the New Jersey Shelf
A one-dimensional, steady state numerical model is developed for estimating cross-shore surface transport in shallow waters, where the water depth is comparable to boundary layer thickness. The model is used to solve a momentum equation which describes the cross-shore balance. To validate the model, acoustic Doppler current profiler (ADCP) current data collected during an experiment off the New Jersey shelf in the summer of 1996 are used to estimate the cross-shore surface transport during that period and then compared with model predictions based on the local wind. The success of the model in estimating the cross-shore surface transport leads to an improved version of the conventional upwelling index (i.e., the Bakun Index), particularly for coastal areas with wide and shallow shelves, such as the east coast of the United States. Finally, the model, because of its simplicity, is well suited for operational applications where computational resources may be limited. Copyright 2010 by the American Geophysical Union., Cited By (since 1996):2, Art. No.: C04017, Oceanography
A model of the iron cycle in the ocean
A model of the iron cycle in the ocean
The IRONEX II in situ fertilization experiment showed decisively that availability of iron limits the growth of phytoplankton in equatorial Pacific surface waters. High-nutrient low-chlorophyll (HNLC) surface waters, potentially iron limited, are also found in the North Pacific and the Southern Ocean. A model of seawater iron geochemistry has been incorporated into a global ocean circulation and carbon cycle model and tuned to match the observed ocean Fe distribution. The model reproduces the observed HNLC areas in the equatorial Pacific and Southern Ocean but predicts nutrient depletion in the North Pacific (a region of high dust fluxes from Asia). The model is based on the idea that the concentrations of organic iron-binding ligands in seawater control the subsurface Fe concentration and predicts that a majority (70-80%) of the global carbon export production can be sustained by upwelling of dissolved iron in seawater rather than by atmospheric deposition. The ocean iron cycle increases the efficiency of iron utilization in the biological pump, buffers new production against interannual fluctuations in iron deposition, and contributes several new intrinsic timescales to the ocean carbon cycle: several hundred years for the ocean iron concentration and perhaps several thousand for the concentration of ligand in the deep sea. Ocean recycling of Fe appears to play a major role in determining the strength of the biological pump in the ocean and the pCO2 of the atmosphere., Cited By (since 1996):117, Oceanography
A new lanternshark (Squaliformes: Etmopteridae: Etmopterus) from Southern Africa
A new lanternshark (Squaliformes: Etmopteridae: Etmopterus) from Southern Africa
A new species of lanternshark, Etmopterus sculptus (Squaliformes: Etmopteridae), is described from southern Africa. The new species closely resembles other members of the "Etmopterus lucifer" group, especially the western North Pacific E. brachyurus, in having linear rows of dermal denticles. The new species is fairly common along the upper continental slopes between Namibia and southern Mozambique at depths between 450 and 900 m. The new species can be distinguished from other members of the E. lucifer species complex by a combination of characteristics, including arrangement of flank and caudal markings, and shape, size, and arrangement of dermal denticles along the body. © 2011 by the American Society of Ichthyologists and Herpetologists., Export Date: 24 September 2013, CODEN: COPAA, Fish and Fisheries
A new legskate (Rajoidei: Genus Cruriraja) from Southern Africa
A new legskate (Rajoidei: Genus Cruriraja) from Southern Africa
A common legskate from southern Africa, misidentified for the last half century as Cruriraja parcomaculata, is redescribed as C. hulleyi. A number of morphometric and meristic characters are identified that distinguish C. hulleyi from C. parcomaculata (=triangularis). Cruriraja hulleyi exhibits midback thorns in a continuous row above the anterior half of the abdominal region, the interdorsal space is usually greater than half the dorsal-fin base length, the clasper eperon is not bifurcate, and the clasper ventral surface lacks dermal denticles. Relative to C. parcomaculata, C. hulleyi is larger, has a shorter snout, smaller eyes, a more obtuse snout angle, fewer lower jaw tooth rows, more turns in the spiral valve, more nuchal thorns, exhibits scapular thorn patches and more predorsal midline thorns, and has a spatulate rather than pointed distal tip of the anterior lobe of the pelvic fin. The two species occur in allopatry, with C. hulleyi ranging from Namibia to the Eastern Cape Coast of South Africa and C. parcomaculata distributed from kwaZulu-Natal, South Africa to Mozambique. © 2010 by the American Society of Ichthyologists and Herpetologists., Cited By (since 1996):1, CODEN: COPAA, Fish and Fisheries
A new species of Malthopsis (Lophiiformes: Ogcocephalidae) from the western Atlantic Ocean
A new species of Malthopsis (Lophiiformes: Ogcocephalidae) from the western Atlantic Ocean
A new species of Malthopsis is described from the western Atlantic Ocean, the first Malthopsis known from anywhere outside the Indo-western Pacific region except for Hawaii. Of 25 depth records, all were 275-475 m except one, which was 91 m., Cited By (since 1996):4, CODEN: BMRSA, Fish and Fisheries
A new species of chimaera, Hydrolagus melanophasma sp. nov. (Chondrichthyes: Chimaeriformes: Chimaeridae), from the eastern North Pacific.
A new species of chimaera, Hydrolagus melanophasma sp. nov. (Chondrichthyes: Chimaeriformes: Chimaeridae), from the eastern North Pacific.
A new species of chimaera, Hydrolagus melanophasma sp. nov. (Chimaeridae), is described from the eastern North Pacific. It is distinct from other eastern Pacific chimaeroids by the following characteristics: a large slightly curved dorsal fin spine extending beyond dorsal fin apex, a long second dorsal fin of uniform height throughout, large pectoral fins extending beyond the pelvic fin insertion when laid flat, trifid claspers forked for approximately one-quarter the total clasper length and a uniform black coloration throughout. The new species is compared to other eastern Pacific members of the genus Hydrolagus including H. alphus, H. colliei, H. macrophthalmus, and H. mccoskeri. Remote Operated Vehicle (ROV) video footage has identified and documented Hydrolagus melanophasma from the Gulf of California. ROV observations suggest that individuals typically occur over soft-bottom habitats or cobble patches with minimal vertical relief. This is in contrast to other eastern Pacific Hydrolagus species that tend to occur in areas of high rocky relief. The known distribution of this new species at present extends from southern California, U.S.A., along the Pacific coast of Baja California, Mexico, and into the Gulf of California. © 2009 Magnolia Press., Cited By (since 1996):6, Fish and Fisheries
A new species of chimaeroid, Hydrolagus alphus sp. nov. (Chimaeriformes: Chimaeridae) from the Galapagos Islands
A new species of chimaeroid, Hydrolagus alphus sp. nov. (Chimaeriformes: Chimaeridae) from the Galapagos Islands
A new species of chimaerid belonging to the genus Hydrolagus Gill, 1862 is described from two specimens collected from the Galapagos Islands. This species was taken from depths ranging from 600 - 900 m. Hydrolagus alphus sp. nov. is distinguished from other members of the genus by having proportionately large eyes, dark brown coloration with a noticeable white spot on lateral side, paired fins with a bluish hue and white distal margins, and second dorsal fin with dark anterior and posterior sections separated by a middle portion indented and completely white. This new species is compared to Hydrolagus macrophthalmus, the most similar congener and Hydrolagus mccoskerii the only other known species within this genus to occur in the eastern South Pacific. Copyright © 2006 Magnolia Press., Cited By (since 1996):9, Fish and Fisheries
A new species of deep-sea catshark (Sycliorhinidae: Bythaelurus) from the southwestern Indian Ocean
A new species of deep-sea catshark (Sycliorhinidae: Bythaelurus) from the southwestern Indian Ocean
Bythaelurus naylori sp. n. is described based on 41 specimens collected from seamounts in the southwestern Indian Ocean. The new species can be separated from all other Bythaelurus species by a combination of distinctly enlarged dermal denticles on the upper caudal-fin margin, lack of papillae on the roof of the mouth and tongue, an anal-fin base length equal to or less than 1.5 times second dorsal-fin base length, and a uniformly plain medium to dark brown body coloration, with light fin edges and a distinct dark dusky-colored snout. No other Bythaelurus species has the combination of a caudal crest of prominent, distinctly enlarged, comb-like dermal denticles along the upper caudal margin and lacks oral papillae. Bythaelurus naylori sp. n. can be distinguished from its two closest cogeners, B. giddingsi and B. lutarius, by a combindation of prominent comb-like dermal denticles along the upper caudal-fin margin, absence of oral papillae, uniform body coloration, and noticeable dark dusky snouth; Bythaelurus giddingsi has oral papillae present and a variegated color pattern, while B. lutarius lacks a caudal crest of enlarged denticles and matures at a much smaller size than the new species.
A new species of eastern Pacific Fissidentalium (Mollusca: Scaphopoda)
A new species of eastern Pacific Fissidentalium (Mollusca: Scaphopoda)
Fissidentalium erosum sp. nov. is described morphometrically from specimens collected from deep water off California. It is distinguished from F. megathyris primarily on the basis of soft-body-part proportions and radular characteristics. Shell differences are slight; the ventral aperture of F. erosum is approximately circular, whereas in F. megathyris the aperture is distinctly wider than high. The posterior portion of Fissidentalium erosum shells is often eroded, in contrast to the uneroded condition of most F. megathyris shells collected at the same station., Cited By (since 1996):3, Invertebrates
A non-native bryozoan creates novel substrate on the mudflats in San Francisco Bay
A non-native bryozoan creates novel substrate on the mudflats in San Francisco Bay
A non-native bryozoan, Schizoporella errata, forms extensive patches of free-living balls and reef-like structures (bryoliths) on the mudflats in south San Francisco Bay, California. The ball-like bryoliths range from 2 to 20 cm in diameter, and the reef-like structures can be nearly 1 m across. While S. errata is known to form bryoliths in other locations, free-living aggregations like these have not been reported. Colony morphology appears to be a plastic trait as analysis of relationships among forms using cytochrome oxidase subunit I (COI) nucleotide sequence data revealed no genetic separation. We recorded >50 species of algae and invertebrates living on and in the bryoliths and determined the invasion status for 34 of the 50 species. Of the 34, 25 (74%) were non-natives and included fouling species that require hard substrate. The bryoliths may thus facilitate colonization by invaders on the mudflats and serve as stepping stones between the limited hard substrate habitats in the Bay. © Inter-Research 2010, www.int-res.com., Cited By (since 1996):3, CODEN: MESED, Invertebrates
A numerical study on the role of wind forcing, bottom topography, and nonhydrostacy in coastal upwelling
A numerical study on the role of wind forcing, bottom topography, and nonhydrostacy in coastal upwelling
The responses of coastal upwelling to different magnitudes of wind stress over a narrow and a wide shelf are studied using a 3-D primitive equation numerical model. The results show that the position of the upwelling front depends on both the strength and the duration of the wind forcing. The comparison between different shelf widths shows that wide shelf will limit the cold water intrusion, so that the corresponding decrease in sea surface temperature is less compared to narrow shelves. Besides, the difference between hydrostatic and nonhydrostatic model results shows that nonhydrostatic effects will enhance the growth of surface meandering, and can be more pronounced near steep fronts. Although difference does exist, our results show that the nonhydrostatic effects are very small at least in this idealized study case. © 2011 Elsevier Ltd., Cited By (since 1996):1, CODEN: ECSSD, Oceanography
A re-appraisal of the total biomass and annual production of Antarctic krill
A re-appraisal of the total biomass and annual production of Antarctic krill
Despite much research on Euphausia superba, estimates of their total biomass and production are still very uncertain. Recently, circumpolar krill databases, combined with growth models and revisions in acoustics have made it possible to refine previous estimates. Net-based databases of density and length frequency (KRILLBASE) yield a summer distributional range of ∼19×10 6km 2 and a mean total abundance of 8×10 14 post-larvae with biomass of 379 million tonnes (Mt). These values are based on a standardised net sampling method but they average over the period 1926-2004, during which krill abundance has fluctuated. To estimate krill biomass at the end of last century we combined the KRILLBASE map of relative krill density around Antarctica with an acoustics-derived biomass estimate of 37.3Mt derived for the Scotia Sea area in 2000 by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Thus the CCAMLR 2000 survey area contains 28% of the total stock, with total biomass of ∼133Mt in January-February 2000. Gross postlarval production is estimated conservatively at 342-536Mtyr -1, based on three independent methods. These are high values, within the upper range of recent estimates, but consistent with the concept of high energy throughput for a species of this size. The similarity between the three production estimates reflects a broad agreement between the three growth models used, plus the fact that, for a given population size, production is relatively insensitive to the size distribution of krill at the start of the growth season. These production values lie within the envelope of what can be supported from the Southern Ocean primary production system and what is required to support an estimated predator consumption of 128-470Mtyr -1. Given the range of recent acoustics estimates, plus the need for precautionary management of the developing krill fishery, our net-based data provide an alternative estimate of total krill biomass. © 2008 Elsevier Ltd., Cited By (since 1996):34, CODEN: DRORE, Antarctica, Invertebrates
A re-description of the eastern Pacific swellshark, Cephaloscyllium ventriosum (Garman 1880) (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), with comments on the status of C. uter (Jordan & Gilbert 1896)
A re-description of the eastern Pacific swellshark, Cephaloscyllium ventriosum (Garman 1880) (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), with comments on the status of C. uter (Jordan & Gilbert 1896)
The genus Cephaloscyllium Gill 1862 (Chondrichthyes, Carcharhiniformes, Scyliorhinidae), arguably has one representative species in the eastern Pacific, C. ventriosum (Garman 1880). While the C. ventriosum holotype was collected from central Chile, a dubious species, C. uter, (Jordan & Gilbert 1896) was described from California. Garman (1913) classified C. uter as a junior synonym of C. ventriosum. This study marks the first morphometric and meristic analysis comparing the holotype of C. ventriosum from Chile with California Cephaloscyllium specimens and presents a revision of the genus for the eastern Pacific. Based on a comparison of morphometric and meristic data from specimens collected from Monterey, California; Santa Catalina Island, California; Santa Barbara, California; Guadalupe Island, Mexico; and Valparaiso, Chile, it is concluded that the California and Chilean Cephaloscyllium species represent a single, wide-ranging species, C. ventriosum. Copyright © 2008 Magnolia Press., Cited By (since 1996):1, Fish and Fisheries
A relationship of diet to prey abundance and the foraging behavior of Trematomus bernacchii
A relationship of diet to prey abundance and the foraging behavior of Trematomus bernacchii
Little information is available regarding fish diets in Antarctica and how they relate to prey availability. The primary objective of this work was to describe the diet of Trematomus bernacchii. The second objective was to compare prey taken with prey present in the benthos along a spatial gradient of prey abundance using Ivlev's Index of Electivity. All samples were collected from 4 different sites on the east side of McMurdo Sound, Antarctica. Fish were captured by divers at the same depth at each site and their stomachs were flushed for dietary analysis. The diet of T. bernacchii varied among sites, and prey selectivity varied inversely with prey abundance. Many of the prey taken by T. bernacchii were sedentary species suggesting that T. bernacchii is a hunt and peck predator. © 1993 Springer-Verlag., Cited By (since 1996):14, CODEN: POBID, Antarctica, Fish and Fisheries
A review of apparent 20th century changes in the presence of mussels (Mytilus trossulus) and macroalgae in Arctic, Alaska, and of historical and paleontological evidence used to relate mollusc distributions to climate change
A review of apparent 20th century changes in the presence of mussels (Mytilus trossulus) and macroalgae in Arctic, Alaska, and of historical and paleontological evidence used to relate mollusc distributions to climate change
Live mussels attached to fresh laminarioid brown algae, all fastened to clusters of pebbles and small cobbles, were repeatedly cast ashore by autumn storms at Barrow, Alaska, in the 1990s. Specimens of Laminaria saccharina and L. solidungula shorten by 100 km a 500 km gap (Peard Bay to Stefansson Sound) between previously known concentrations of these kelp species. For the genus Mytilus, a 1 600 km gap in fully documented locations existed between Kivalina in the southern Chukchi Sea and the Mackenzie River delta. Barrow specimens were identified using a mitochondrial DNA marker as M. trossulus, an identity consistent with dispersal from the Pacific-Bering side of the Arctic. Live mussels and macroalgae were neither washed up by storms nor collected by active biological sampling during extensive benthic surveys at Barrow in 1948-50. We cannot interpret the current presence of these bivalves and macrophytes as Arctic range extensions due to warming, similar to those manifested by the tree line in terrestrial systems and by Pacific salmon in marine environments. Supplemental information and critical evaluation of survey strategies and rationales indicate that changes in sea temperatures are an unlikely cause. Alternative explanations focus on past seafloor disturbances, dispersal from marine or estuarine refugia, and effects of predators on colonists. This review suggests refining some interpretations of environmental change that are based on the extensive resource of Cenozoic fossils of Arctic molluscs., Cited By (since 1996):16, CODEN: ATICA, Invertebrates
A review of the methods and problems of quantitative assessment of Loligo opalescens
A review of the methods and problems of quantitative assessment of Loligo opalescens
An examination of the knowledge about sampling Loligo opalescens populations leads to two general conclusions regarding the assessment of their abundance. First, it is suggested that studies concentrate on spawning ground organisms, since they aggregate during spawning, are commercially fished at this time, and their numbers can be assessed using a combination of data from market catch, adult and egg case densities, acoustic sensing, and perhaps larval densities. Second, it is suggested that large-scale acoustic surveys coupled with large midwater trawling activities be used to qualitatively assess adult organisms off the spawning grounds.
A review of the systematics of western North Pacific angel sharks, genus Squatina, with redescriptions of Squatina formosa, S. japonica, and S. nebulosa (Chondrichthyes: Squatiniformes, Squatinidae)
A review of the systematics of western North Pacific angel sharks, genus Squatina, with redescriptions of Squatina formosa, S. japonica, and S. nebulosa (Chondrichthyes: Squatiniformes, Squatinidae)
Squatinids are quite distinct from other shark-like fishes, but individual species are difficult to differentiate. Four of the 16 known, valid squatinid species occur in the western North Pacific (WNP). Differences among the WNP species complex have traditionally relied upon the nasal barbel shape, interorbital and interspiracle distances, ocellus patterns, number of dermal folds about the mouth, and the presence of midback thorns. Unfortunately, many of these characters are difficult to distinguish, hindering identification of individuals. Using WNP squatinid specimens and photographs, both from field expeditions and museums, we confirm the validity of four species in the area. Additionally, we correct mistakes made in the literature on S. formosa type material, clarify differences in the particularly challenging distinction between S. formosa and S. nebulosa, and provide the basis for a revised dichotomous key for the region that includes all four known valid WNP squatinid species. Copyright © 2007 Magnolia Press., Cited By (since 1996):9, Fish and Fisheries
A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species.
A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species.
The genus Cephaloscyllium Gill 1862 (Chondrichthyes, Carcharhiniformes, Scyliorhinidae) until recently had only two species recognized, C. isabellum [= C. umbratile (Jordan & Fowler 1903)] and C. fasciatum Chan 1966, from the western North Pacific (WNP), with one dubious species, C. formosanum, having been described by Teng in 1962. Recently, three additional species were described, C. circulopullum Yano et al. 2005, C. sarawakensis Yano et al. 2005, and C. parvum Inoue & Nakaya 2006 from this region. Here we present a revision of this genus for the WNP, including redescriptions of C. fasciatum and C. umbratile based on the holotypes, a re-examination of the recently described species, and descriptions of two new species from Taiwan. Cephaloscyllium umbratile can be distinguished from its congeners based on maximum size, length of first dorsal-fin base, anal-caudal space, and dorsal-caudal space. We conclude, based on a comparison of C. parvum and C. sarawakensis, that the former is a junior synonym of the latter species. The two new Taiwanese species can be separated from other WNP species by color pattern, shape of the anterior nasal flap, anal and dorsal-fin size, internarial width, and mouth size. Finally, we present a revised dichotomous key to the WNP Cephaloscyllium recognizing six contemporary taxa: C. circulopullum, C. fasciatum, C. sarawakensis, C. umbratile, C. pardelotum sp. nov. and C. maculatum sp. nov. Copyright © 2008 Magnolia Press., Cited By (since 1996):2, Fish and Fisheries
A rosette system for the collection of trace metal clean seawater
A rosette system for the collection of trace metal clean seawater
We designed a large-volume rosette sampler for collecting seawater with minimal trace metal contamination. The system uses eight modified 30-liter Go-Flo bottles secured to a Nylon II-coated stainless steel frame. The instrument is deployed with a dedicated winch with polyurethane-coated, three-conductor Kevlar hydroline. A prototype was used as part of the U.S. JGOFS Equatorial Pacific sampling program during spring and fall 1992. A redesigned model was used during the 1993 IronEx experiments and is currently being deployed in the Arabian Sea. The results of trace metal analyses collected on these cruises indicate that samples recovered are comparable to current single Go-Flo casts., Cited By (since 1996):28, CODEN: LIOCA, Oceanography, Downloaded from: www.aslo.org/lo/toc/vol_41/issue_6/1367.pdf (23 June 2014).
A shark antibody heavy chain encoded by a nonsomatically rearranged VDJ is preferentially expressed in early development and is convergent with mammalian IgG
A shark antibody heavy chain encoded by a nonsomatically rearranged VDJ is preferentially expressed in early development and is convergent with mammalian IgG
In most vertebrate embryos and neonates studied to date unique antigen receptors (antibodies and T cell receptors) are expressed that possess a limited immune repertoire. We have isolated a subclass of IgM, IgM1gj, from the nurse shark Ginglymostoma cirratum that is preferentially expressed in neonates. The variable (V) region gene encoding the heavy (H) chain underwent V-D-J rearrangement in germ cells "germline-joined"). Such H chain V genes were discovered over 10 years ago in sharks but until now were not shown to be expressed at appreciable levels; we find expression of H1gj in primary and secondary lymphoid tissues early in life, but in adults only in primary lymphoid tissue, which is identified in this work as the epigonal organ. H1gj chain associates covalently with light (L) chains and is most similar in sequence to IgM H chains, but like mammalian IgG has three rather than the four IgM constant domains; deletion of the ancestral IgM C2 domain thus defines both IgG and IgM1gj. Because sharks are the members of the oldest vertebrate class known to possess antibodies, unique or specialized antibodies expressed early in ontogeny in sharks and other vertebrates were likely present at the inception of the adaptive immune system., Cited By (since 1996):41, CODEN: PNASA, Fish and Fisheries
A shipboard comparison of analytic methods for ballast water compliance monitoring
A shipboard comparison of analytic methods for ballast water compliance monitoring
Abstract Promising approaches for indicative analysis of ballast water samples have been developed that require study in the field to examine their utility for determining compliance with the International Convention for the Control and Management of Ships' Ballast Water and Sediments. To address this gap, a voyage was undertaken on board the RV Meteor, sailing the North Atlantic Ocean from Mindelo (Cape Verde) to Hamburg (Germany) during June 4–15, 2015. Trials were conducted on local sea water taken up by the ship's ballast system at multiple locations along the trip, including open ocean, North Sea, and coastal water, to evaluate a number of analytic methods that measure the numeric concentration or relative biomass of viable organisms according to two size categories (≥ 50 μm in minimum dimension: 7 techniques, ≥ 10 μm and < 50 μm: 9 techniques). Water samples were analyzed in parallel to determine whether results were similar between methods and whether rapid, indicative methods offer comparable results to standard, time- and labor-intensive detailed methods (e.g. microscopy) and high-end scientific approaches (e.g. flow cytometry). Several promising indicative methods were identified that showed high correlation with microscopy, but allow much quicker processing and require less expert knowledge. This study is the first to concurrently use a large number of analytic tools to examine a variety of ballast water samples on board an operational ship in the field. Results are useful to identify the merits of each method and can serve as a basis for further improvement and development of tools and methodologies for ballast water compliance monitoring.

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