1
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Browning TJ, Moore CM. Global analysis of ocean phytoplankton nutrient limitation reveals high prevalence of co-limitation. Nat Commun 2023; 14:5014. [PMID: 37591895 PMCID: PMC10435517 DOI: 10.1038/s41467-023-40774-0] [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: 12/02/2022] [Accepted: 08/09/2023] [Indexed: 08/19/2023] Open
Abstract
Nutrient availability limits phytoplankton growth throughout much of the global ocean. Here we synthesize available experimental data to identify three dominant nutrient limitation regimes: nitrogen is limiting in the stratified subtropical gyres and in the summertime Arctic Ocean, iron is most commonly limiting in upwelling regions, and both nutrients are frequently co-limiting in regions in between the nitrogen and iron limited systems. Manganese can be co-limiting with iron in parts of the Southern Ocean, whilst phosphate and cobalt can be co-/serially limiting in some settings. Overall, an analysis of experimental responses showed that phytoplankton net growth can be significantly enhanced through increasing the number of different nutrients supplied, regardless of latitude, temperature, or trophic status, implying surface seawaters are often approaching nutrient co-limitation. Assessments of nutrient deficiency based on seawater nutrient concentrations and nutrient stress diagnosed via molecular biomarkers showed good agreement with experimentally-assessed nutrient limitation, validating conceptual and theoretical links between nutrient stoichiometry and microbial ecophysiology.
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Affiliation(s)
- Thomas J Browning
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, Kiel, 24148, Germany.
| | - C Mark Moore
- School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, UK.
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2
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Anugerahanti P, Tagliabue A. Process controlling iron-manganese regulation of the Southern Ocean biological carbon pump. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220065. [PMID: 37150202 PMCID: PMC10164462 DOI: 10.1098/rsta.2022.0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Iron (Fe) is a key limiting nutrient driving the biological carbon pump and is routinely represented in global ocean biogeochemical models. However, in the Southern Ocean, the potential role for other micronutrients has not received the same attention. For example, although manganese (Mn) is essential to photosynthetic oxygen production and combating oxidative stress, it is not included in ocean models and a clear understanding of its interaction with Fe in the region is lacking. This is especially important for the Southern Ocean because both Mn and Fe are strongly depleted. We use a hierarchical modelling approach to explore how the physiological traits associated with Fe and Mn contribute to driving the footprint of micronutrient stress across different phytoplankton functional types (PFTs). We find that PFT responses are driven by physiological traits associated with their physiological requirements and acclimation to environmental conditions. Southern Ocean-specific adaptations to prevailing low Fe, such as large photosynthetic antenna sizes, are of major significance for the regional biological carbon pump. Other traits more strongly linked to Mn, such as dealing with oxidative stress, may become more important under a changing Fe supply regime. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.
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Affiliation(s)
- Prima Anugerahanti
- Department of Earth, University of Liverpool, Ocean, and Ecological Sciences, 4 Brownlow Street, Liverpool L69 3GP, UK
| | - Alessandro Tagliabue
- Department of Earth, University of Liverpool, Ocean, and Ecological Sciences, 4 Brownlow Street, Liverpool L69 3GP, UK
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3
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Hawco NJ, Tagliabue A, Twining BS. Manganese Limitation of Phytoplankton Physiology and Productivity in the Southern Ocean. GLOBAL BIOGEOCHEMICAL CYCLES 2022; 36:e2022GB007382. [PMID: 37034112 PMCID: PMC10078217 DOI: 10.1029/2022gb007382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 05/24/2023]
Abstract
Although iron and light are understood to regulate the Southern Ocean biological carbon pump, observations have also indicated a possible role for manganese. Low concentrations in Southern Ocean surface waters suggest manganese limitation is possible, but its spatial extent remains poorly constrained and direct manganese limitation of the marine carbon cycle has been neglected by ocean models. Here, using available observations, we develop a new global biogeochemical model and find that phytoplankton in over half of the Southern Ocean cannot attain maximal growth rates because of manganese deficiency. Manganese limitation is most extensive in austral spring and depends on phytoplankton traits related to the size of photosynthetic antennae and the inhibition of manganese uptake by high zinc concentrations in Antarctic waters. Importantly, manganese limitation expands under the increased iron supply of past glacial periods, reducing the response of the biological carbon pump. Overall, these model experiments describe a mosaic of controls on Southern Ocean productivity that emerge from the interplay of light, iron, manganese and zinc, shaping the evolution of Antarctic phytoplankton since the opening of the Drake Passage.
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Affiliation(s)
- Nicholas J. Hawco
- Department of OceanographyUniversity of Hawaiʻi at MānoaHonoluluHIUSA
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4
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Hogle SL, Hackl T, Bundy RM, Park J, Satinsky B, Hiltunen T, Biller S, Berube PM, Chisholm SW. Siderophores as an iron source for picocyanobacteria in deep chlorophyll maximum layers of the oligotrophic ocean. THE ISME JOURNAL 2022; 16:1636-1646. [PMID: 35241788 PMCID: PMC9122953 DOI: 10.1038/s41396-022-01215-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 11/09/2022]
Abstract
Prochlorococcus and Synechococcus are the most abundant photosynthesizing organisms in the oceans. Gene content variation among picocyanobacterial populations in separate ocean basins often mirrors the selective pressures imposed by the region's distinct biogeochemistry. By pairing genomic datasets with trace metal concentrations from across the global ocean, we show that the genomic capacity for siderophore-mediated iron uptake is widespread in Synechococcus and low-light adapted Prochlorococcus populations from deep chlorophyll maximum layers of iron-depleted regions of the oligotrophic Pacific and S. Atlantic oceans: Prochlorococcus siderophore consumers were absent in the N. Atlantic ocean (higher new iron flux) but constituted up to half of all Prochlorococcus genomes from metagenomes in the N. Pacific (lower new iron flux). Picocyanobacterial siderophore consumers, like many other bacteria with this trait, also lack siderophore biosynthesis genes indicating that they scavenge exogenous siderophores from seawater. Statistical modeling suggests that the capacity for siderophore uptake is endemic to remote ocean regions where atmospheric iron fluxes are the smallest, especially at deep chlorophyll maximum and primary nitrite maximum layers. We argue that abundant siderophore consumers at these two common oceanographic features could be a symptom of wider community iron stress, consistent with prior hypotheses. Our results provide a clear example of iron as a selective force driving the evolution of marine picocyanobacteria.
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Affiliation(s)
- Shane L Hogle
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Biology, University of Turku, Turku, Finland.
| | - Thomas Hackl
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Randelle M Bundy
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Jiwoon Park
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Brandon Satinsky
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Teppo Hiltunen
- Department of Biology, University of Turku, Turku, Finland
| | - Steven Biller
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biological Sciences, Wellesley College, Wellesley, MA, USA
| | - Paul M Berube
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sallie W Chisholm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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5
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Richon C, Tagliabue A. Biogeochemical feedbacks associated with the response of micronutrient recycling by zooplankton to climate change. GLOBAL CHANGE BIOLOGY 2021; 27:4758-4770. [PMID: 34228873 PMCID: PMC9292334 DOI: 10.1111/gcb.15789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/27/2021] [Accepted: 06/28/2021] [Indexed: 05/24/2023]
Abstract
Recycling by zooplankton has emerged as an important process driving the cycling of essential micronutrients in the upper ocean. Resupply of nutrients by upper ocean recycling is itself controlled by multiple biotic and abiotic factors. Although the response of these drivers to climate change will shape future recycling rates and their stoichiometry, their magnitude and variability are unaddressed by climate change projections, which means potentially important feedbacks on surface biogeochemistry are neglected. Here, we assess the impacts of climate change under the high emissions RCP8.5 scenario on the recycling of the essential micronutrients Fe, Zn, Cu, Co and Mn and quantify the regional control by zooplankton food quality, prey quantity, sea surface temperature and zooplankton biomass. A statistical assessment of our model results reveals that the variability in recycling fluxes across all micronutrients is mainly driven by the variability of zooplankton and prey biomass. In contrast, the variability in micronutrient recycling stoichiometry and its response to climate change are more complex and is regulated by zooplankton food quality and prey quantity. Regionally, the relative influence of each driver on recycling changes in our model by the end of the 21st century. Temperature becomes an important driving factor in the polar regions while the expansion of oligotrophic regions leads to the importance of food quality increase for low and mid-latitudes. These responses lead to novel feedbacks that can amplify the response of surface ocean biogeochemistry and alter nutrient deficiency regimes.
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Affiliation(s)
- Camille Richon
- School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
- Present address:
Laboratoire d'Océanographie Physique et Spatiale UMR 197 CNRS/IFREMER/IRD/UBO Institut Universitaire Européen de la MerPlouzané29280France
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6
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Browning TJ, Achterberg EP, Engel A, Mawji E. Manganese co-limitation of phytoplankton growth and major nutrient drawdown in the Southern Ocean. Nat Commun 2021; 12:884. [PMID: 33563991 PMCID: PMC7873070 DOI: 10.1038/s41467-021-21122-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/13/2021] [Indexed: 01/30/2023] Open
Abstract
Residual macronutrients in the surface Southern Ocean result from restricted biological utilization, caused by low wintertime irradiance, cold temperatures, and insufficient micronutrients. Variability in utilization alters oceanic CO2 sequestration at glacial-interglacial timescales. The role for insufficient iron has been examined in detail, but manganese also has an essential function in photosynthesis and dissolved concentrations in the Southern Ocean can be strongly depleted. However, clear evidence for or against manganese limitation in this system is lacking. Here we present results from ten experiments distributed across Drake Passage. We found manganese (co-)limited phytoplankton growth and macronutrient consumption in central Drake Passage, whilst iron limitation was widespread nearer the South American and Antarctic continental shelves. Spatial patterns were reconciled with the different rates and timescales for removal of each element from seawater. Our results suggest an important role for manganese in modelling Southern Ocean productivity and understanding major nutrient drawdown in glacial periods.
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Affiliation(s)
- Thomas J. Browning
- grid.15649.3f0000 0000 9056 9663Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Eric P. Achterberg
- grid.15649.3f0000 0000 9056 9663Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Anja Engel
- grid.15649.3f0000 0000 9056 9663Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Edward Mawji
- grid.418022.d0000 0004 0603 464XNational Oceanography Centre Southampton, Southampton, UK
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7
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Krisch S, Browning TJ, Graeve M, Ludwichowski KU, Lodeiro P, Hopwood MJ, Roig S, Yong JC, Kanzow T, Achterberg EP. The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait, North Greenland Sea. Sci Rep 2020; 10:15230. [PMID: 32943713 PMCID: PMC7499181 DOI: 10.1038/s41598-020-72100-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/25/2020] [Indexed: 11/14/2022] Open
Abstract
Climate change has led to a ~ 40% reduction in summer Arctic sea-ice cover extent since the 1970s. Resultant increases in light availability may enhance phytoplankton production. Direct evidence for factors currently constraining summertime phytoplankton growth in the Arctic region is however lacking. GEOTRACES cruise GN05 conducted a Fram Strait transect from Svalbard to the NE Greenland Shelf in summer 2016, sampling for bioessential trace metals (Fe, Co, Zn, Mn) and macronutrients (N, Si, P) at ~ 79°N. Five bioassay experiments were conducted to establish phytoplankton responses to additions of Fe, N, Fe + N and volcanic dust. Ambient nutrient concentrations suggested N and Fe were deficient in surface seawater relative to typical phytoplankton requirements. A west-to-east trend in the relative deficiency of N and Fe was apparent, with N becoming more deficient towards Greenland and Fe more deficient towards Svalbard. This aligned with phytoplankton responses in bioassay experiments, which showed greatest chlorophyll-a increases in + N treatment near Greenland and + N + Fe near Svalbard. Collectively these results suggest primary N limitation of phytoplankton growth throughout the study region, with conditions potentially approaching secondary Fe limitation in the eastern Fram Strait. We suggest that the supply of Atlantic-derived N and Arctic-derived Fe exerts a strong control on summertime nutrient stoichiometry and resultant limitation patterns across the Fram Strait region.
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Affiliation(s)
- Stephan Krisch
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
| | - Thomas J Browning
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
| | - Martin Graeve
- Alfred-Wegener-Institute for Polar and Marine Research, 27570, Bremerhaven, Germany
| | - Kai-Uwe Ludwichowski
- Alfred-Wegener-Institute for Polar and Marine Research, 27570, Bremerhaven, Germany
| | - Pablo Lodeiro
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
| | - Mark J Hopwood
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
| | - Stéphane Roig
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
| | - Jaw-Chuen Yong
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
| | - Torsten Kanzow
- Alfred-Wegener-Institute for Polar and Marine Research, 27570, Bremerhaven, Germany
| | - Eric P Achterberg
- Marine Biogeochemistry Division, GEOMAR Helmholtz Centre for Ocean Research, 24148, Kiel, Germany.
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8
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Zhang X, Ward BB, Sigman DM. Global Nitrogen Cycle: Critical Enzymes, Organisms, and Processes for Nitrogen Budgets and Dynamics. Chem Rev 2020; 120:5308-5351. [DOI: 10.1021/acs.chemrev.9b00613] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xinning Zhang
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Bess B. Ward
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel M. Sigman
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
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Anderson RF. GEOTRACES: Accelerating Research on the Marine Biogeochemical Cycles of Trace Elements and Their Isotopes. ANNUAL REVIEW OF MARINE SCIENCE 2020; 12:49-85. [PMID: 31337253 DOI: 10.1146/annurev-marine-010318-095123] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The biogeochemical cycles of trace elements and their isotopes (TEIs) constitute an active area of oceanographic research due to their role as essential nutrients for marine organisms and their use as tracers of oceanographic processes. Selected TEIs also provide diagnostic information about the physical, geological, and chemical processes that supply or remove solutes in the ocean. Many of these same TEIs provide information about ocean conditions in the past, as their imprint on marine sediments can be interpreted to reflect changes in ocean circulation, biological productivity, the ocean carbon cycle, and more. Other TEIs have been introduced as the result of human activities and are considered contaminants. The development and implementation of contamination-free methods for collecting and analyzing samples for TEIs revolutionized marine chemistry, revealing trace element distributions with oceanographically consistent features and new insights about the processes regulating them. Despite these advances, the volume and geographic coverage of high-quality TEI data by the end of the twentieth century were insufficient to constrain their global biogeochemical cycles. To accelerate progress in this field of research, marine geochemists developed a coordinated international effort to systematically study the marine biogeochemical cycles of TEIs-the GEOTRACES program. Following a decade of planning and implementation, GEOTRACES launched its main field effort in 2010. This review, roughly midway through the field program, summarizes the steps involved in designing the program, its management structure, and selected findings.
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Affiliation(s)
- Robert F Anderson
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA;
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10
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Tagliabue A, Bowie AR, DeVries T, Ellwood MJ, Landing WM, Milne A, Ohnemus DC, Twining BS, Boyd PW. The interplay between regeneration and scavenging fluxes drives ocean iron cycling. Nat Commun 2019; 10:4960. [PMID: 31673108 PMCID: PMC6823497 DOI: 10.1038/s41467-019-12775-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/30/2019] [Indexed: 01/18/2023] Open
Abstract
Despite recent advances in observational data coverage, quantitative constraints on how different physical and biogeochemical processes shape dissolved iron distributions remain elusive, lowering confidence in future projections for iron-limited regions. Here we show that dissolved iron is cycled rapidly in Pacific mode and intermediate water and accumulates at a rate controlled by the strongly opposing fluxes of regeneration and scavenging. Combining new data sets within a watermass framework shows that the multidecadal dissolved iron accumulation is much lower than expected from a meta-analysis of iron regeneration fluxes. This mismatch can only be reconciled by invoking significant rates of iron removal to balance iron regeneration, which imply generation of authigenic particulate iron pools. Consequently, rapid internal cycling of iron, rather than its physical transport, is the main control on observed iron stocks within intermediate waters globally and upper ocean iron limitation will be strongly sensitive to subtle changes to the internal cycling balance. Iron is crucial for marine photosynthesis, but observational constraints on the magnitude of key iron cycle processes are lacking. Here the authors use a range of observational data sets to demonstrate that the balance between iron re-supply and removal in the subsurface controls upper ocean iron limitation.
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Affiliation(s)
| | - Andrew R Bowie
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobsart, TAS, Australia
| | - Timothy DeVries
- University of California Santa Barbara, Santa Barbara, CA, USA
| | - Michael J Ellwood
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | | | - Angela Milne
- Florida State University, Tallahassee, FL, USA.,University of Plymouth, Plymouth, UK
| | | | | | - Philip W Boyd
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobsart, TAS, Australia
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