Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf
The cyanobacterium Trichodesmium plays an essential role supporting ocean productivity by relieving nitrogen limitation via dinitrogen (N2) fixation. The two common Trichodesmium clades, T. erythraeum and T. thiebautii, are both observed in waters along the West Florida Shelf (WFS). We hypothesized...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-06-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.821655/full |
| _version_ | 1811329963970789376 |
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| author | Kristina A. Confesor Corday R. Selden Corday R. Selden Kimberly E. Powell Laura A. Donahue Travis Mellett Travis Mellett Salvatore Caprara Angela N. Knapp Kristen N. Buck P. Dreux Chappell |
| author_facet | Kristina A. Confesor Corday R. Selden Corday R. Selden Kimberly E. Powell Laura A. Donahue Travis Mellett Travis Mellett Salvatore Caprara Angela N. Knapp Kristen N. Buck P. Dreux Chappell |
| author_sort | Kristina A. Confesor |
| collection | DOAJ |
| description | The cyanobacterium Trichodesmium plays an essential role supporting ocean productivity by relieving nitrogen limitation via dinitrogen (N2) fixation. The two common Trichodesmium clades, T. erythraeum and T. thiebautii, are both observed in waters along the West Florida Shelf (WFS). We hypothesized that these taxa occupy distinct realized niches, where T. thiebautii is the more oceanic clade. Samples for DNA and water chemistry analyses were collected on three separate WFS expeditions (2015, 2018, and 2019) spanning multiple seasons; abundances of the single copy housekeeping gene rnpB from both clades were enumerated via quantitative PCR. We conducted a suite of statistical analyses to assess Trichodesmium clade abundances in the context of the physicochemical data. We observed a consistent coastal vs. open ocean separation of the two clades: T. erythraeum was found in shallow waters where the concentrations of dissolved iron (dFe) and the groundwater tracer Ba were significantly higher, while T. thiebautii abundance was positively correlated with water column depth. The Loop Current intrusion in 2015 with entrained Missisippi River water brought higher dFe and elevated abundance of both clades offshore of the 50 m isobath, suggesting that both clades are subject to Fe limitation on the outer shelf. Whereas, previous work has observed that T. thiebautii is more abundant than T. erythraeum in open ocean surface waters, this is the first study to examine Trichodesmium niche differentiation in a coastal environment. Understanding the environmental niches of these two key taxa bears important implications for their contributions to global nitrogen and carbon cycling and their response to global climate change. |
| first_indexed | 2024-04-13T15:54:09Z |
| format | Article |
| id | doaj.art-7446e03fe45e4316b3df2cb53685935d |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-13T15:54:09Z |
| publishDate | 2022-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-7446e03fe45e4316b3df2cb53685935d2022-12-22T02:40:46ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-06-01910.3389/fmars.2022.821655821655Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida ShelfKristina A. Confesor0Corday R. Selden1Corday R. Selden2Kimberly E. Powell3Laura A. Donahue4Travis Mellett5Travis Mellett6Salvatore Caprara7Angela N. Knapp8Kristen N. Buck9P. Dreux Chappell10Old Dominion University, Department of Ocean and Earth Sciences, Norfolk, VA, United StatesOld Dominion University, Department of Ocean and Earth Sciences, Norfolk, VA, United StatesRutgers University, Department of Marine and Coastal Sciences, New Brunswick, NJ, United StatesOld Dominion University, Department of Ocean and Earth Sciences, Norfolk, VA, United StatesDepartment of Biology Haverford College, Haverford, PA, United StatesUniversity of South Florida, College of Marine Science, St. Petersburg, FL, United StatesUniversity of Washington, School of Oceanography, Seattle, WA, United StatesUniversity of South Florida, College of Marine Science, St. Petersburg, FL, United StatesFlorida State University, Department of Earth, Ocean, and Atmospheric Sciences, Tallahassee, FL, United StatesUniversity of South Florida, College of Marine Science, St. Petersburg, FL, United StatesOld Dominion University, Department of Ocean and Earth Sciences, Norfolk, VA, United StatesThe cyanobacterium Trichodesmium plays an essential role supporting ocean productivity by relieving nitrogen limitation via dinitrogen (N2) fixation. The two common Trichodesmium clades, T. erythraeum and T. thiebautii, are both observed in waters along the West Florida Shelf (WFS). We hypothesized that these taxa occupy distinct realized niches, where T. thiebautii is the more oceanic clade. Samples for DNA and water chemistry analyses were collected on three separate WFS expeditions (2015, 2018, and 2019) spanning multiple seasons; abundances of the single copy housekeeping gene rnpB from both clades were enumerated via quantitative PCR. We conducted a suite of statistical analyses to assess Trichodesmium clade abundances in the context of the physicochemical data. We observed a consistent coastal vs. open ocean separation of the two clades: T. erythraeum was found in shallow waters where the concentrations of dissolved iron (dFe) and the groundwater tracer Ba were significantly higher, while T. thiebautii abundance was positively correlated with water column depth. The Loop Current intrusion in 2015 with entrained Missisippi River water brought higher dFe and elevated abundance of both clades offshore of the 50 m isobath, suggesting that both clades are subject to Fe limitation on the outer shelf. Whereas, previous work has observed that T. thiebautii is more abundant than T. erythraeum in open ocean surface waters, this is the first study to examine Trichodesmium niche differentiation in a coastal environment. Understanding the environmental niches of these two key taxa bears important implications for their contributions to global nitrogen and carbon cycling and their response to global climate change.https://www.frontiersin.org/articles/10.3389/fmars.2022.821655/fullTrichodesmiumdiazotrophsniche separationcoastal/ocean separationWest Florida Shelfgroundwater |
| spellingShingle | Kristina A. Confesor Corday R. Selden Corday R. Selden Kimberly E. Powell Laura A. Donahue Travis Mellett Travis Mellett Salvatore Caprara Angela N. Knapp Kristen N. Buck P. Dreux Chappell Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf Frontiers in Marine Science Trichodesmium diazotrophs niche separation coastal/ocean separation West Florida Shelf groundwater |
| title | Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf |
| title_full | Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf |
| title_fullStr | Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf |
| title_full_unstemmed | Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf |
| title_short | Defining the Realized Niche of the Two Major Clades of Trichodesmium: A Study on the West Florida Shelf |
| title_sort | defining the realized niche of the two major clades of trichodesmium a study on the west florida shelf |
| topic | Trichodesmium diazotrophs niche separation coastal/ocean separation West Florida Shelf groundwater |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.821655/full |
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