1
|
Zhu Y, Mulholland MR, Bernhardt PW, Neeley AR, Widner B, Tapia AM, Echevarria MA. Nitrogen uptake rates and phytoplankton composition across contrasting North Atlantic Ocean coastal regimes north and south of Cape Hatteras. Front Microbiol 2024; 15:1380179. [PMID: 38784802 PMCID: PMC11113559 DOI: 10.3389/fmicb.2024.1380179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
Understanding nitrogen (N) uptake rates respect to nutrient availability and the biogeography of phytoplankton communities is crucial for untangling the complexities of marine ecosystems and the physical, biological, and chemical forces shaping them. In the summer of 2016, we conducted measurements of bulk microbial uptake rates for six 15N-labeled substrates: nitrate, nitrite, ammonium, urea, cyanate, and dissolve free amino acids across distinct marine provinces, including the continental shelf of the Mid-and South Atlantic Bights (MAB and SAB), the Slope Sea, and the Gulf Stream, marking the first instance of simultaneously measuring six different N uptake rates in this dynamic region. Total measured N uptake rates were lowest in the Gulf Stream followed by the SAB. Notably, the MAB exhibited significantly higher N uptake rates compared to the SAB, likely due to the excess levels of pre-existing phosphorus present in the MAB. Together, urea and nitrate uptake contributed approximately 50% of the total N uptake across the study region. Although cyanate uptake rates were consistently low, they accounted for up to 11% of the total measured N uptake at some Gulf Stream stations. Phytoplankton groups were identified based on specific pigment markers, revealing a dominance of diatoms in the shelf community, while Synechococcus, Prochlorococcus, and pico-eukaryotes dominated in oligotrophic Gulf Stream waters. The reported uptake rates in this study were mostly in agreement with previous studies conducted in coastal waters of the North Atlantic Ocean. This study suggests there are distinct regional patterns of N uptake in this physically dynamic region, correlating with nutrient availability and phytoplankton community composition. These findings contribute valuable insights into the intricate interplay of biological and chemical factors shaping N dynamics in disparate marine ecosystems.
Collapse
Affiliation(s)
- Yifan Zhu
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
- Department of Marine Sciences, University of Connecticut, Groton, CT, United States
| | - Margaret R. Mulholland
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
| | - Peter W. Bernhardt
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
| | | | - Brittany Widner
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
| | - Alfonso Macías Tapia
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
- Office of Education, National Oceanic and Atmospheric Administration, Silver Spring, MD, United States
| | - Michael A. Echevarria
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, United States
| |
Collapse
|
2
|
Li J, Wang Z, Yang H, Wang Z, Liu F, Chen X, Huang X. Phosphorus forms and zinc concentrations affect the physiological ecology and sinking rate of Thalassiosira weissflogii. MARINE POLLUTION BULLETIN 2024; 200:116124. [PMID: 38325204 DOI: 10.1016/j.marpolbul.2024.116124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
The combined effects of phosphorus (P) forms and zinc (Zn) concentrations on diatom silicification remain unclear. In this study, we investigate the effects of different Zn concentrations on the growth, cellular silicon content and sinking rate of Thalassiosira weissflogii under different P forms. The results showed that under the dissolved inorganic phosphorus (DIP) treatments, the specific growth rate of T. weissflogii in Zn limitation culture was significantly lower than that in Zn-replete culture. However, T. weissflogii cellular silicon content and sinking rate increased. Moreover, the reduced specific growth rate (7 %, p < 0.05), enhanced ALP activity (63 %, p < 0.05), and sinking rate (20 %, p < 0.05) for Zn-deplete T. weissflogii implied that the bioavailability of dissolved organic phosphorus (DOP) was depressed under Zn deplete medium. This study demonstrates that the physiological ecology and sinking rate of the diatom T. weissflogii were affected by both individual and combined changes in P forms and Zn concentrations.
Collapse
Affiliation(s)
- Jiandi Li
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Zhaofei Wang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Hang Yang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Zhenfeng Wang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China
| | - Fengjiao Liu
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China
| | - Xiaohuang Chen
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China
| | - Xuguang Huang
- College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 363000, China.
| |
Collapse
|
3
|
Masuda T, Inomura K, Mareš J, Kodama T, Shiozaki T, Matsui T, Suzuki K, Takeda S, Deutsch C, Prášil O, Furuya K. Coexistence of Dominant Marine Phytoplankton Sustained by Nutrient Specialization. Microbiol Spectr 2023; 11:e0400022. [PMID: 37458590 PMCID: PMC10441275 DOI: 10.1128/spectrum.04000-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 06/07/2023] [Indexed: 08/19/2023] Open
Abstract
Prochlorococcus and Synechococcus are the two dominant picocyanobacteria in the low-nutrient surface waters of the subtropical ocean, but the basis for their coexistence has not been quantitatively demonstrated. Here, we combine in situ microcosm experiments and an ecological model to show that this coexistence can be sustained by specialization in the uptake of distinct nitrogen (N) substrates at low-level concentrations that prevail in subtropical environments. In field incubations, the response of both Prochlorococcus and Synechococcus to nanomolar N amendments demonstrates N limitation of growth in both populations. However, Prochlorococcus showed a higher affinity to ammonium, whereas Synechococcus was more adapted to nitrate uptake. A simple ecological model demonstrates that the differential nutrient preference inferred from field experiments with these genera may sustain their coexistence. It also predicts that as the supply of NO3- decreases, as expected under climate warming, the dominant genera should undergo a nonlinear shift from Synechococcus to Prochlorococcus, a pattern that is supported by subtropical field observations. Our study suggests that the evolution of differential nutrient affinities is an important mechanism for sustaining the coexistence of genera and that climate change is likely to shift the relative abundance of the dominant plankton genera in the largest biomes in the ocean. IMPORTANCE Our manuscript addresses the following fundamental question in microbial ecology: how do different plankton using the same essential nutrients coexist? Prochlorococcus and Synechococcus are the two dominant picocyanobacteria in the low-nutrient surface waters of the subtropical ocean, which support a significant amount of marine primary production. The geographical distributions of these two organisms are largely overlapping, but the basis for their coexistence in these biomes remains unclear. In this study, we combined in situ microcosm experiments and an ecosystem model to show that the coexistence of these two organisms can arise from specialization in the uptake of distinct nitrogen substrates; Prochlorococcus prefers ammonium, whereas Synechococcus prefers nitrate when these nutrients exist at low concentrations. Our framework can be used for simulating and predicting the coexistence in the future ocean and may provide hints toward understanding other similar types of coexistence.
Collapse
Affiliation(s)
- Takako Masuda
- Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo, Japan
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czechia
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Jan Mareš
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czechia
- Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budejovice, Czechia
- Department of Botany, University of South Bohemia, Faculty of Science, České Budejovice, Czechia
| | - Taketoshi Kodama
- Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Takuhei Shiozaki
- Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Takato Matsui
- Graduate School of Environmental Science/Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Koji Suzuki
- Graduate School of Environmental Science/Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
| | - Shigenobu Takeda
- Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Curtis Deutsch
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czechia
| | - Ken Furuya
- Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo, Japan
| |
Collapse
|