National Ocean Service

About: National Ocean Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Algal bloom & Population. The organization has 500 authors who have published 643 publications receiving 46096 citations.

Performing centimeter-level surveys in seconds with gps carrier phase: initial results

Abstract: Two kinematic surveys were performed, using TI-4100s, which substantiate the author’s earlier claim that centimeter-accuracy relative surveys can be accomplished within seconds. The first test was carried out in Arkansas using wide-bandwidth tracking. Although noisy, these data permitted the concepts and the data processing software to be verified. Based on results of this survey, a definitive kinematic survey experiment was designed and executed at the National Bureau of Standards, Gaithersburg, MD. The results of this experiment show that centimeter-level relative surveys can be performed in seconds. A priori geodetic coordinates of the initial location of the “roving” antenna are not required since they, too, can be determined within seconds.

Chimeric Plastid Proteome in the Florida “Red Tide” Dinoflagellate Karenia brevis

Abstract: Current understanding of the plastid proteome comes almost exclusively from studies of plants and red algae. The proteome in these taxa has a relatively simple origin via integration of proteins from a single cyanobacterial primary endosymbiont and the host. However, the most successful algae in marine environments are the chlorophyll c-containing chromalveolates such as diatoms and dinoflagellates that contain a plastid of red algal origin derived via secondary or tertiary endosymbiosis. Virtually nothing is known about the plastid proteome in these taxa. We analyzed expressed sequence tag data from the toxic "Florida red tide" dinoflagellate Karenia brevis that has undergone a tertiary plastid endosymbiosis. Comparative analyses identified 30 nuclear-encoded plastid-targeted proteins in this chromalveolate that originated via endosymbiotic or horizontal gene transfer (HGT) from multiple different sources. We identify a fundamental divide between plant/red algal and chromalveolate plastid proteomes that reflects a history of mixotrophy in the latter group resulting in a highly chimeric proteome. Loss of phagocytosis in the "red" and "green" clades effectively froze their proteomes, whereas chromalveolate lineages retain the ability to engulf prey allowing them to continually recruit new, potentially adaptive genes through subsequent endosymbioses and HGT. One of these genes is an electron transfer protein (plastocyanin) of green algal origin in K. brevis that likely allows this species to thrive under conditions of iron depletion.

Antimicrobial peptides derived from hemoglobin are expressed in epithelium of channel catfish (Ictalurus punctatus, Rafinesque)

Abstract: The β-chain of the respiratory protein hemoglobin (Hbβ), has recently been identified in novel sites, including mammalian macrophages and alveolar epithelium, as well as in gill microsomes of fish. However, the functional significance of extra-erythrocytically expressed hemoglobin has been unclear. Here we show inducible expression and upregulation of antimicrobial peptides (AMPs) homologous to Hbβ in the gill epithelium of channel catfish (Ictalurus punctatus) in response to parasitic (Ichthyophthirius multifiliis, ich) infection. One peptide (HbβP-1), while having activity against some fish bacterial pathogens (e.g., Aeromonas hydrophila), had especially potent antiparasitic activity that was specifically lethal (lytic) to the feeding (trophont) stage of ich and also appeared to accelerate the differentiation of trophonts. However, it had no apparent effect on either the disseminative (theront) or reproductive (tomont) stages, nor was it lytic to channel catfish erythrocytes. Fish experimentally challenged with ich confirmed that the HbβP-1 sequence was both transcribed and translated in skin and gill epithelium, the target tissues for ich. The Hb AMP concentration expressed in vivo appeared to be well within the antiparasitic concentrations measured in vitro. Our findings suggest that hemoglobin-derived AMPs might play a significant role in the non-specific immune response.

Causality of an extreme harmful algal bloom in Monterey Bay, California, during the 2014-2016 northeast Pacific warm anomaly

Abstract: An ecologically and economically disruptive harmful algal bloom (HAB) affected much of the northeast Pacific margin in 2015, during a prolonged oceanic warm anomaly Caused by diatoms of the genus Pseudo-nitzschia, this HAB produced the highest particulate concentrations of the biotoxin domoic acid (DA) ever recorded in Monterey Bay, California Bloom inception followed strong upwelling during the spring transition, which introduced nutrients and eliminated the warm anomaly locally Subsequently, moderate and intermittent upwelling created favorable conditions for growth and accumulation of HAB biomass, which was dominated by a highly toxigenic species, P australis High cellular DA concentrations were associated with available nitrogen for DA synthesis coincident with silicate exhaustion This nutrient influence resulted from two factors: (1) disproportionate depletion of silicate in upwelling source waters during the warm anomaly, the most severe depletion observed in 24 years, and (2) silicate uptake by the dense diatom bloom

Permanent and functional male-to-female sex reversal in d-rR strain medaka (Oryzias latipes) following egg microinjection of o,p'-DDT.

Abstract: Complete sex reversal of fish is accomplished routinely in aquaculture practices by exposing fish to exogenous sex steroids during gonadal differentiation. A variety of environmental chemicals are also active at sex steroid receptors and theoretically possess the potential to alter normal sexual differentiation in fish. However, in controlled environmental chemical exposures to date, only partial alterations of fish sexual phenotype have been observed. Here we report complete, permanent, and functional male-to-female sex reversal in the Japanese medaka (Oryzias latipes, d-rR strain) after a onetime embryonic exposure to the xenoestrogen o, p'-DDT. d-rR strain medaka are strict gonochorists that possesses both sex-linked pigmentation, which distinguishes genotypic sex, and sexually dimorphic external secondary sexual characteristics, which distinguish phenotypic sex. We directly microinjected the xenoestrogen o, p'-DDT into the egg yolks of medaka at fertilization to parallel the maternal transfer of lipophilic contaminants to the embryo. At 10 weeks of age, microinjected medaka were examined for mortality and sex reversal. A calculated embryonic dose of 511 +/- 22 ng/egg o, p'-DDT (mean +/- standard error) resulted in 50% mortality. An embryonic exposure of 227 +/- 22 ng/egg o, p'-DDT resulted in 86% (6 of 7) sex reversal of genetic males to a female phenotype (XY females). XY females were distinguished by sex-linked male pigmentation accompanying female secondary sexual characteristics. Histologic examination of the gonads confirmed active ovaries in 100% of the XY females. In 10-day breeding trials in which XY females were paired with normal XY males, 50% of the XY females produced fertilized embryos; this represents a comparable breeding success rate to normal XX females. Fertilized eggs produced from XY females hatched to viable larvae. These results clearly indicate that a weakly estrogenic pesticide, o, p'-DDT, when presented during the critical period of gonadal development, can profoundly alter sexual differentiation.