國立虎尾科技大學 |

Nitrogen, Microbes, Particles and Oxygen Deficient Zones.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Nitrogen, Microbes, Particles and Oxygen Deficient Zones./
Author:	Huanca Valenzuela, Paulina Alejandra.
Description:	1 online resource (173 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
Contained By:	Dissertations Abstracts International85-12B.
Subject:	Biological oceanography. -
Online resource:	click for full text (PQDT)
ISBN:	9798383178089

Nitrogen, Microbes, Particles and Oxygen Deficient Zones.
Huanca Valenzuela, Paulina Alejandra.

Nitrogen, Microbes, Particles and Oxygen Deficient Zones. - 1 online resource (173 pages)

Source: Dissertations Abstracts International, Volume: 85-12, Section: B.

Thesis (Ph.D.)--University of Maryland, College Park, 2024.

Includes bibliographical references

Single-celled microbes mediate most biogeochemical cycling in the ocean. Ammonium is generally the preferred reduced nitrogen form microbes use for assimilation and growth. However, ammonium is often removed to undetectable levels from offshore waters. Microorganisms can metabolize alternative organic reduced nitrogen forms in the absence of ammonium, if they possess genes encoding for the enzymes cyanase (cynS), and urease (ureC), which catalyze the decomposition of cyanate and urea respectively. It is unknown which microbes contain these genes in the environment.In my first chapter, I quantified the microbes that can use cyanate and/or urea in oxic and anoxic (ODZ) environments by using a phylogenetic read placement technique. First, I explored depth profiles of metagenomes from two Pacific Ocean regions: an oxic region represented by the nutrient limited Hawaii Ocean Time series, and two ODZ environments represented by the Eastern Tropical South and the North Pacific. A larger proportion of N2 producing anammox bacteria in ODZs have the ability to utilize cyanate than urea, while a larger proportion of nitrite oxidizing Nitrospina have the ability to utilize urea than cyanate. Ammonia-oxidizing Thaumarchaeota had the ability to use urea in deep oxic waters. Contrastingly, the majority of heterotrophic SAR11 bacteria had the ability to use urea in surface waters, but none did in deep waters. This structuring of who can utilize which reduced N form could reflect competition between microbes and N availability. For my second chapter, I examined microbial ability to use urea and cyanate across time and space using metagenomes from two oceanic Geotraces transects in the North Atlantic; GA02 a North-South spring transect, and GA03, a Fall West to East transect. The two transects differed in nutrient concentrations, affecting the composition of phytoplankton communities. Though eukaryotic phytoplankton were abundant on the spring GA02 transect, they did not have the ability to use urea or cyanate, probably because ammonia was present. However, the ability to use urea was still common in SAR11. Cyanobacteria Synechococcus was abundant on this transect and had the ability to use cyanate. In the nutrient limited fall GA03 transect, the results were similar to oxic waters in chapter 1 except that towards the east, cyanobacteria Prochlorococcus gained the ability to utilize cyanate. Both seasonal and spatial changes were observed in the distribution of ureC and cynS genes in microbial groups in the North Atlantic.My third chapter focuses on organisms living on suspended particles. Marine particles constitute a niche that provides ample nutrient and carbon sources. Large particles have been postulated to support anaerobic metabolism that cannot occur in the surrounding water. We examined how microbial diversity changes among a range of 7 different particle sizes in a depth profile at the East Pacific Rise, an area of the ocean with a distinct oxygen minimum. By combining a quantitative 16S rRNA amplicon sequencing dataset with size fractionated organic matter concentrations, we estimated numbers of each microbial taxa per gram of carbon. Results show differences in microbial composition at different particle sizes and depths.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798383178089Subjects--Topical Terms:

1178855
Biological oceanography.
Subjects--Index Terms:

CyanateIndex Terms--Genre/Form:

554714
Electronic books.

Nitrogen, Microbes, Particles and Oxygen Deficient Zones.
LDR:04666ntm a22004097 4500 001 1150323
005 20241028114746.5
006 m o d
007 cr bn ---uuuuu
008 250605s2024 xx obm 000 0 eng d
020 $a 9798383178089
035 $a (MiAaPQ)AAI30991397
035 $a AAI30991397
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Huanca Valenzuela, Paulina Alejandra. $3 1476785
245 1 0 $a Nitrogen, Microbes, Particles and Oxygen Deficient Zones.
264 0 $c 2024
300 $a 1 online resource (173 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
500 $a Advisor: Fuchsman, Clara A.;Cram, Jacob A.
502 $a Thesis (Ph.D.)--University of Maryland, College Park, 2024.
504 $a Includes bibliographical references
520 $a Single-celled microbes mediate most biogeochemical cycling in the ocean. Ammonium is generally the preferred reduced nitrogen form microbes use for assimilation and growth. However, ammonium is often removed to undetectable levels from offshore waters. Microorganisms can metabolize alternative organic reduced nitrogen forms in the absence of ammonium, if they possess genes encoding for the enzymes cyanase (cynS), and urease (ureC), which catalyze the decomposition of cyanate and urea respectively. It is unknown which microbes contain these genes in the environment.In my first chapter, I quantified the microbes that can use cyanate and/or urea in oxic and anoxic (ODZ) environments by using a phylogenetic read placement technique. First, I explored depth profiles of metagenomes from two Pacific Ocean regions: an oxic region represented by the nutrient limited Hawaii Ocean Time series, and two ODZ environments represented by the Eastern Tropical South and the North Pacific. A larger proportion of N2 producing anammox bacteria in ODZs have the ability to utilize cyanate than urea, while a larger proportion of nitrite oxidizing Nitrospina have the ability to utilize urea than cyanate. Ammonia-oxidizing Thaumarchaeota had the ability to use urea in deep oxic waters. Contrastingly, the majority of heterotrophic SAR11 bacteria had the ability to use urea in surface waters, but none did in deep waters. This structuring of who can utilize which reduced N form could reflect competition between microbes and N availability. For my second chapter, I examined microbial ability to use urea and cyanate across time and space using metagenomes from two oceanic Geotraces transects in the North Atlantic; GA02 a North-South spring transect, and GA03, a Fall West to East transect. The two transects differed in nutrient concentrations, affecting the composition of phytoplankton communities. Though eukaryotic phytoplankton were abundant on the spring GA02 transect, they did not have the ability to use urea or cyanate, probably because ammonia was present. However, the ability to use urea was still common in SAR11. Cyanobacteria Synechococcus was abundant on this transect and had the ability to use cyanate. In the nutrient limited fall GA03 transect, the results were similar to oxic waters in chapter 1 except that towards the east, cyanobacteria Prochlorococcus gained the ability to utilize cyanate. Both seasonal and spatial changes were observed in the distribution of ureC and cynS genes in microbial groups in the North Atlantic.My third chapter focuses on organisms living on suspended particles. Marine particles constitute a niche that provides ample nutrient and carbon sources. Large particles have been postulated to support anaerobic metabolism that cannot occur in the surrounding water. We examined how microbial diversity changes among a range of 7 different particle sizes in a depth profile at the East Pacific Rise, an area of the ocean with a distinct oxygen minimum. By combining a quantitative 16S rRNA amplicon sequencing dataset with size fractionated organic matter concentrations, we estimated numbers of each microbial taxa per gram of carbon. Results show differences in microbial composition at different particle sizes and depths.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Biological oceanography. $3 1178855
650 4 $a Aquatic sciences. $3 1178821
650 4 $a Biogeochemistry. $3 642004
653 $a Cyanate
653 $a Marine particles
653 $a Microbes
653 $a Nitrogen
653 $a Oxygen deficient zones
653 $a Urease
655 7 $a Electronic books. $2 local $3 554714
690 $a 0416
690 $a 0425
690 $a 0792
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of Maryland, College Park. $b Marine-Estuarine-Environmental Sciences. $3 1476786
773 0 $t Dissertations Abstracts International $g 85-12B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30991397 $z click for full text (PQDT)