scholarly journals Origin, composition and nutritional quality of particulate matter at deep-sea hydrothermal vents on Axial Volcano, NE Pacific

2005 ◽  
Vol 289 ◽  
pp. 43-52 ◽  
Author(s):  
C Levesque ◽  
H Limén ◽  
SK Juniper
Keyword(s):  
Particulate Matter ◽  
Deep Sea ◽  
Nutritional Quality ◽  
Hydrothermal Vents ◽  
Axial Volcano ◽  
Ne Pacific

scholarly journals A new species and phylogenetic insights in Hesiospina (Annelida, Hesionidae) 

Zootaxa ◽  
2018 ◽  
Vol 4441 (1) ◽  
pp. 59 ◽  
Author(s):  
PAULO BONIFÁCIO ◽  
YANN LELIÈVRE ◽  
EMMANUELLE OMNES
Keyword(s):  
New Species ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Juan De Fuca Ridge ◽  
Cold Seeps ◽  
Molecular Analyses ◽  
The Third ◽  
Juan De Fuca ◽  
Ne Pacific ◽  
A New Species

Hesionids are a very speciose group of polychaetes. In the deep sea, they occur in different environments such as hydrothermal vents, cold seeps, abyssal depths or whale falls. In the present study, a new species of Hesionidae, Hesiospina legendrei sp. nov. has been identified based on morphological and molecular (16S and COI genes) data from hydrothermal vents located in Juan de Fuca Ridge (NE Pacific Ocean). This new species is characterized by trapezoid prostomium; proboscis with high number of distal papillae (20–27), a pair of sac-like structures inserted ventro-laterally in proboscis; notopodia lobe reduced with multiple, slender aciculae on segments 1–5; and neuropodia developed with single, simple chaeta, and numerous, heterogomph falcigers, with 1–2 inferiormost having elongated hood. Hesiospina legendrei sp. nov. is the third described species in the genus. Sequences from the two previously described Hesiospina species are included in the molecular analyses, and although the genes used in this study are not sufficient to resolve the relationships on genus level, the result raises questions about the cosmopolitan aspect of H. vestimentifera. 

scholarly journals Phylogenetic Diversity of Nitrogenase (nifH) Genes in Deep-Sea and Hydrothermal Vent Environments of the Juan de Fuca Ridge

2003 ◽  
Vol 69 (2) ◽  
pp. 960-970 ◽  
Author(s):  
Mausmi P. Mehta ◽  
David A. Butterfield ◽  
John A. Baross
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Pcr Primers ◽  
Deep Seawater ◽  
Nitrogen Fixers ◽  
Axial Volcano ◽  
Microbial Habitat ◽  
Biological Nitrogen ◽  
Ocean Ridge

ABSTRACT The subseafloor microbial habitat associated with typical unsedimented mid-ocean-ridge hydrothermal vent ecosystems may be limited by the availability of fixed nitrogen, inferred by the low ammonium and nitrate concentrations measured in diffuse hydrothermal fluid. Dissolved N2 gas, the largest reservoir of nitrogen in the ocean, is abundant in deep-sea and hydrothermal vent fluid. In order to test the hypothesis that biological nitrogen fixation plays an important role in nitrogen cycling in the subseafloor associated with unsedimented hydrothermal vents, degenerate PCR primers were designed to amplify the nitrogenase iron protein gene nifH from hydrothermal vent fluid. A total of 120 nifH sequences were obtained from four samples: a nitrogen-poor diffuse vent named marker 33 on Axial Volcano, sampled twice over a period of 1 year as its temperature decreased; a nitrogen-rich diffuse vent near Puffer on Endeavour Segment; and deep seawater with no detectable hydrothermal plume signal. Subseafloor nifH genes from marker 33 and Puffer are related to anaerobic clostridia and sulfate reducers. Other nifH genes unique to the vent samples include proteobacteria and divergent Archaea. All of the nifH genes from the deep-seawater sample are most closely related to the thermophilic, anaerobic archaeon Methanococcus thermolithotrophicus (77 to 83% amino acid similarity). These results provide the first genetic evidence of potential nitrogen fixers in hydrothermal vent environments and indicate that at least two sources contribute to the diverse assemblage of nifH genes detected in hydrothermal vent fluid: nifH genes from an anaerobic, hot subseafloor and nifH genes from cold, oxygenated deep seawater.

scholarly journals Protistan grazing impacts microbial communities and carbon cycling at deep-sea hydrothermal vents

2021 ◽  
Author(s):  
Sarah K. Hu ◽  
Erica L. Herrera ◽  
Amy R. Smith ◽  
Maria G. Pachiadaki ◽  
Virginia P. Edgcomb ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Grazing Pressure ◽  
Trophic Levels ◽  
Predator Prey ◽  
Gorda Ridge ◽  
Ne Pacific ◽  
Protistan Grazing

AbstractMicrobial eukaryotes (or protists) in marine ecosystems are a link between microbial primary producers and all higher trophic levels. The rate at which heterotrophic protistan grazers consume microbial prey and recycle organic matter is an important factor that influences marine microbial food webs and carbon cycling. At deep-sea hydrothermal vents, chemosynthetic bacteria and archaea form the base of a food web that functions in the absence of sunlight, but the role of protistan grazers in these highly productive ecosystems is largely unexplored. Here, we pair grazing experiments with a molecular survey to quantify protistan grazing and to characterize the composition of vent-associated protists in low-temperature venting fluids from Gorda Ridge in the North East (NE) Pacific Ocean. Results reveal protists exert higher predation pressure at vents compared to the surrounding deep seawater environment and may account for consuming 28-62% of the daily stock of prokaryotic biomass within the hydrothermal vent food web. The vent-associated protistan community was more species rich relative to the background deep sea, and patterns in the distribution and co-occurrence of vent microbes provide additional insights into potential predator-prey interactions. Ciliates, followed by dinoflagellates, Syndiniales, rhizaria, and stramenopiles dominated the vent protist community and included bacterivorous species, species known to host symbionts, and parasites. Our findings provide an estimate of protistan grazing pressure within hydrothermal vent food webs, highlighting the role that diverse deep-sea protistan communities have in carbon cycling.SignificanceHeterotrophic protists are ubiquitous in all aquatic ecosystems and represent an important ecological link because they transfer organic carbon from primary producers to higher trophic levels. Here, we quantify the predator-prey trophic interaction among protistan grazers and microbial prey at multiple sites of hydrothermal venting near the Gorda Ridge spreading center in the NE Pacific Ocean. Grazing pressure was higher at the site of active diffuse flow and was carried out by a highly diverse assemblage of protistan species; elevated grazing rates are attributed to higher concentrations of chemosynthetic microorganisms and biological diversity localized to hydrothermal vent environments.

Food procurement in English-language Canadian public schools: Opportunities and challenges

2019 ◽  
Vol 6 (1) ◽  
pp. 75-99
Author(s):  
Shawna Holmes
Keyword(s):  
Public Schools ◽  
Food Environment ◽  
Nutritional Quality ◽  
English Language ◽  
Nutrient Content ◽  
Food Environments ◽  
School Food ◽  
Provincial Level ◽  
School Food Environment

This paper examines the changes to procurement for school food environments in Canada as a response to changes to nutrition regulations at the provincial level. Interviews with those working in school food environments across Canada revealed how changes to the nutrition requirements of foods and beverages sold in schools presented opportunities to not only improve the nutrient content of the items made available in school food environments, but also to include local producers and/or school gardens in procuring for the school food environment. At the same time, some schools struggle to procure nutritionally compliant foods due to increased costs associated with transporting produce to rural, remote, or northern communities as well as logistic difficulties like spoilage. Although the nutrition regulations have facilitated improvements to food environments in some schools, others require more support to improve the overall nutritional quality of the foods and beverages available to students at school.

IMPROVING THE NUTRITIONAL QUALITY OF FODDER YEASTS BY ADDING MINERALS

2016 ◽  
Vol 15 (5) ◽  
pp. 1009-1017
Author(s):  
Cristina-Gabriela Grigoras ◽  
Andrei I. Simion ◽  
Livia Manea ◽  
Lidia Favier-Teodorescu ◽  
Lucian Gavrila
Keyword(s):  
Nutritional Quality
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