1
|
Evolution of Phytoplankton in Relation to Their Physiological Traits. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10020194] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Defining the physiological traits that characterise phytoplankton involves comparison with related organisms in benthic habitats. Comparison of survival time in darkness under natural conditions requires more information. Gas vesicles and flagella as mechanisms of upward movement relative to surrounding water, allowing periodic vertical migration, are not confined to plankton, although buoyancy changes related to compositional changes of a large central vacuole may be restricted to plankton. Benthic microalgae have the same range of photosynthetic pigments as phytoplankton; it is not clear if there are differences in the rate of regulation and acclimation of photosynthetic machinery to variations in irradiance for phytoplankton and for microphytobenthos. There are inadequate data to determine if responses to variations in frequency or magnitude of changes in the supply of inorganic carbon, nitrogen or phosphorus differ between phytoplankton and benthic microalgae. Phagophotomixotrophy and osmophotomixotrophy occur in both phytoplankton and benthic microalgae. Further progress in identifying physiological traits specific to phytoplankton requires more experimentation on benthic microalgae that are closely related to planktonic microalgae, with attention to whether the benthic algae examined have, as far as can be determined, never been planktonic during their evolution or are derived from planktonic ancestors.
Collapse
|
2
|
Behrenfeld MJ, Halsey KH, Boss E, Karp‐Boss L, Milligan AJ, Peers G. Thoughts on the evolution and ecological niche of diatoms. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1457] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Michael J. Behrenfeld
- Department of Botany and Plant Pathology Oregon State University 4575 SW Research Way Corvallis Oregon 97333 USA
| | - Kimberly H. Halsey
- Department of Microbiology Oregon State University Nash Hall 226 Corvallis Oregon 97331 USA
| | - Emmanuel Boss
- School of Marine Sciences University of Maine 5706 Aubert Hall Orono Maine 04469‐5706 USA
| | - Lee Karp‐Boss
- School of Marine Sciences University of Maine 5706 Aubert Hall Orono Maine 04469‐5706 USA
| | - Allen J. Milligan
- Department of Botany and Plant Pathology Oregon State University 4575 SW Research Way Corvallis Oregon 97333 USA
| | - Graham Peers
- Department of Biology Colorado State University Biology Building, Room 111, 1878 Campus Delivery Fort Collins Colorado 80523‐1878 USA
| |
Collapse
|
3
|
Behrenfeld MJ, Boss ES, Halsey KH. Phytoplankton community structuring and succession in a competition-neutral resource landscape. ISME COMMUNICATIONS 2021; 1:12. [PMID: 36720909 PMCID: PMC9645248 DOI: 10.1038/s43705-021-00011-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/02/2021] [Accepted: 03/11/2021] [Indexed: 02/03/2023]
Abstract
Phytoplankton community composition and succession affect aquatic food webs and biogeochemistry. Resource competition is commonly viewed as an important governing factor for community structuring and this perception is imbedded in modern ecosystem models. Quantitative consideration of the physical spacing between phytoplankton cells, however, suggests that direct competition for growth-limiting resources is uncommon. Here we describe how phytoplankton size distributions and temporal successions are compatible with a competition-neutral resource landscape. Consideration of phytoplankton-herbivore interactions with proportional feeding size ranges yields small-cell dominated size distributions consistent with observations for stable aquatic environments, whereas predator-prey temporal lags and blooming physiologies shift this distribution to larger mean cell sizes in temporally dynamic environments. We propose a conceptual mandala for understanding phytoplankton community composition where species successional series are initiated by environmental disturbance, guided by the magnitude of these disturbances and nutrient stoichiometry, and terminated with the return toward a 'stable solution'. Our conceptual mandala provides a framework for interpreting and modeling the environmental structuring of natural phytoplankton populations.
Collapse
Affiliation(s)
- Michael J Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
| | - Emmanuel S Boss
- School of Marine Sciences, University of Maine, Orono, ME, USA
| | - Kimberly H Halsey
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
| |
Collapse
|
4
|
Lavoie M, Raven JA. How can large-celled diatoms rapidly modulate sinking rates episodically? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3386-3389. [PMID: 32161972 PMCID: PMC7364400 DOI: 10.1093/jxb/eraa129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/07/2020] [Indexed: 06/10/2023]
Affiliation(s)
- Michel Lavoie
- Québec-Océan and Unité Mixte Internationale Takuvik Ulaval-CNRS, Département de Biologie, Université Laval, Québec-Océan, Québec, Canada
| | - John A Raven
- Division of Plant Science, University of Dundee, The James Hutton Institute, Invergowrie, Dundee, UK
- School of Biological Sciences, University of Western Australia, Crawley (Perth), WA, Australia
- Climate Changer Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| |
Collapse
|
5
|
Wirtz K, Smith SL. Vertical migration by bulk phytoplankton sustains biodiversity and nutrient input to the surface ocean. Sci Rep 2020; 10:1142. [PMID: 31980670 PMCID: PMC6981162 DOI: 10.1038/s41598-020-57890-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/08/2020] [Indexed: 11/09/2022] Open
Abstract
Phytoplankton subsumes the great variety of unicellular photoautotrophs that perform roughly half of Earth's primary production. They achieve this despite their challenging oceanic habitat, with opposing vertical gradients of nutrients (which often limit their growth near the surface) and light (which becomes limiting with increasing depth). Most phytoplankton species are commonly assumed to be incapable of moving actively between the zones of light and nutrient availability, which are separated vertically by from 30-120 m. Here we propose that a considerable fraction of phytoplankton vertically traverse these gradients over time scales from hours to weeks, employing variations of a common migration strategy to acquire multiple resources. We present a mechanistic Lagrangian model resolving phytoplankton growth linked to optimal migration behaviour and demonstrate unprecedented agreement of its calculated vertical CHL-a distributions with 773 profiles observed at five prominent marine time-series stations. Our simulations reveal that vertically cycling phytoplankton can pump up enough nutrient to sustain as much as half of oceanic Net Primary Production (NPP). Active locomotion is therefore a plausible mechanism enabling relatively high NPP in the oligotrophic surface ocean. Our simulations also predict similar fitness for a variety of very different migration strategies, which helps to explain the puzzling diversity of phytoplankton observed in the ocean.
Collapse
Affiliation(s)
- Kai Wirtz
- Institute of Coastal Research, Helmholtz Centre Geesthacht, Geesthacht, Germany.
| | - S Lan Smith
- Earth SURFACE System Research Center, Research Institute for Global Change, JAMSTEC, Yokosuka, Japan
| |
Collapse
|
6
|
Harke MJ, Frischkorn KR, Haley ST, Aylward FO, Zehr JP, Dyhrman ST. Periodic and coordinated gene expression between a diazotroph and its diatom host. ISME JOURNAL 2018; 13:118-131. [PMID: 30116042 DOI: 10.1038/s41396-018-0262-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/28/2018] [Accepted: 07/28/2018] [Indexed: 01/30/2023]
Abstract
In the surface ocean, light fuels photosynthetic carbon fixation of phytoplankton, playing a critical role in ecosystem processes including carbon export to the deep sea. In oligotrophic oceans, diatom-diazotroph associations (DDAs) play a keystone role in ecosystem function because diazotrophs can provide otherwise scarce biologically available nitrogen to the diatom host, fueling growth and subsequent carbon sequestration. Despite their importance, relatively little is known about the nature of these associations in situ. Here we used metatranscriptomic sequencing of surface samples from the North Pacific Subtropical Gyre (NPSG) to reconstruct patterns of gene expression for the diazotrophic symbiont Richelia and we examined how these patterns were integrated with those of the diatom host over day-night transitions. Richelia exhibited significant diel signals for genes related to photosynthesis, N2 fixation, and resource acquisition, among other processes. N2 fixation genes were significantly co-expressed with host nitrogen uptake and metabolism, as well as potential genes involved in carbon transport, which may underpin the exchange of nitrogen and carbon within this association. Patterns of expression suggested cell division was integrated between the host and symbiont across the diel cycle. Collectively these data suggest that symbiont-host physiological ecology is strongly interconnected in the NPSG.
Collapse
Affiliation(s)
- Matthew J Harke
- Lamont-Doherty Earth Observatory, Biology and Paleo Environment, Columbia University, Palisades, NY, USA
| | - Kyle R Frischkorn
- Lamont-Doherty Earth Observatory, Biology and Paleo Environment, Columbia University, Palisades, NY, USA.,Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
| | - Sheean T Haley
- Lamont-Doherty Earth Observatory, Biology and Paleo Environment, Columbia University, Palisades, NY, USA
| | - Frank O Aylward
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | | | - Sonya T Dyhrman
- Lamont-Doherty Earth Observatory, Biology and Paleo Environment, Columbia University, Palisades, NY, USA. .,Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA.
| |
Collapse
|
7
|
Anderson EE, Wilson C, Knap AH, Villareal TA. Summer diatom blooms in the eastern North Pacific gyre investigated with a long-endurance autonomous surface vehicle. PeerJ 2018; 6:e5387. [PMID: 30128189 PMCID: PMC6098680 DOI: 10.7717/peerj.5387] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/17/2018] [Indexed: 11/20/2022] Open
Abstract
Satellite chlorophyll a (chl a) observations have repeatedly noted summertime phytoplankton blooms in the North Pacific subtropical gyre (NPSG), a region of open ocean that is far removed from any land-derived or Ekman upwelling nutrient sources. These blooms are dominated by N2-fixing diatom-cyanobacteria associations of the diatom genera Rhizosolenia Brightwell and Hemiaulus Ehrenberg. Their nitrogen fixing endosymbiont, Richelia intracellularis J.A. Schmidt, is hypothesized to be critical to the development of blooms in this nitrogen limited region. However, due to the remote location and unpredictable duration of the summer blooms, prolonged in situ observations are rare outside of the Station ALOHA time-series off of Hawai'i. In summer, 2015, a proof-of-concept mission using the autonomous vehicle, Honey Badger (Wave Glider SV2; Liquid Robotics, a Boeing company, Sunnyvale, CA, USA), collected near-surface (<20 m) observations in the NPSG using hydrographic, meteorological, optical, and imaging sensors designed to focus on phytoplankton abundance, distribution, and physiology of this bloom-forming region. Hemiaulus and Rhizosolenia cell abundance was determined using digital holography for the entire June-November mission. Honey Badger was not able to reach the 30°N subtropical front region where most of the satellite chl a blooms have been observed, but near-real time navigational control allowed it to transect two blooms near 25°N. The two taxa did not co-occur in large numbers, rather the blooms were dominated by either Hemiaulus or Rhizosolenia. The August 2-4, 2015 bloom was comprised of 96% Hemiaulus and the second bloom, August 15-17, 2015, was dominated by Rhizosolenia (75%). The holograms also imaged undisturbed, fragile Hemiaulus aggregates throughout the sampled area at ∼10 L-1. Aggregated Hemiaulus represented the entire observed population at times and had a widespread distribution independent of the summer export pulse, a dominant annual event suggested to be mediated by aggregate fluxes. Aggregate occurrence was not consistent with a density dependent formation mechanism and may represent a natural growth form in undisturbed conditions. The photosynthetic potential index (Fv:Fm) increased from ∼0.4 to ∼0.6 during both blooms indicating a robust, active phytoplankton community in the blooms. The diel pattern of Fv:Fm (nocturnal maximum; diurnal minimum) was consistent with macronutrient limitation throughout the mission with no evidence of Fe-limitation despite the presence of nitrogen fixing diatom-diazotroph assemblages. During the 5-month mission, Honey Badger covered ∼5,690 km (3,070 nautical miles), acquired 9,336 holograms, and reliably transmitted data onshore in near real-time. Software issues developed with the active fluorescence sensor that terminated measurements in early September. Although images were still useful at the end of the mission, fouling of the LISST-Holo optics was considerable, and appeared to be the most significant issue facing deployments of this duration.
Collapse
Affiliation(s)
- Emily E. Anderson
- Department of Marine Science and Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, USA
| | - Cara Wilson
- National Marine Fisheries, National Oceanic and Atmospheric Administration, Monterey, CA, USA
| | - Anthony H. Knap
- Geochemical and Environmental Research Group, Texas A&M University, College Station, TX, USA
| | - Tracy A. Villareal
- Department of Marine Science and Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, USA
| |
Collapse
|
8
|
Lavoie M, Raven JA, Levasseur M. Energy cost and putative benefits of cellular mechanisms modulating buoyancy in aflagellate marine phytoplankton. JOURNAL OF PHYCOLOGY 2016; 52:239-251. [PMID: 27037589 DOI: 10.1111/jpy.12390] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 01/15/2016] [Indexed: 06/05/2023]
Abstract
Little information is available on the energetics of buoyancy modulation in aflagellate phytoplankton, which comprises the majority of autotrophic cells found in the ocean. Here, we computed for three aflagellate species of marine phytoplankton (Emiliania huxleyi, Thalassiosira pseudonana, and Ethmodiscus rex) the theoretical minimum energy cost as photons absorbed and nitrogen resource required of the key physiological mechanisms (i.e., replacement of quaternary ammonium by dimethyl-sulfoniopropionate, storage of polysaccharides, and cell wall biosynthesis) affecting the cell's vertical movement as a function of nitrogen (N) availability. These energy costs were also normalized to the capacity of each buoyancy mechanism to modulate sinking or rising rates based on Stokes' law. The three physiological mechanisms could act as ballast in the three species tested in conditions of low N availability at a low fraction (<12%) of the total photon energy cost for growth. Cell wall formation in E. huxleyi was the least costly ballast strategy, whereas in T. pseudonana, the photon energy cost of the three ballast strategies was similar. In E. rex, carbohydrate storage and mobilization appear to be energetically cheaper than modulations in organic solute synthesis to achieve vertical migration. This supports the carbohydrate-ballast strategy for vertical migration for this species, but argues against the theory of replacement of low- or high-density organic solutes. This study brings new insights into the energy cost and potential selective advantages of several strategies modulating the buoyancy of aflagellate marine phytoplankton.
Collapse
Affiliation(s)
- Michel Lavoie
- Québec-Océan and Unité Mixte Internationale Takuvik Ulaval-CNRS, Département de Biologie, Université Laval, Québec, Québec, Canada, G1V 0A6
| | - John A Raven
- Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Functional Plant Biology and Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Maurice Levasseur
- Québec-Océan and Unité Mixte Internationale Takuvik Ulaval-CNRS, Département de Biologie, Université Laval, Québec, Québec, Canada, G1V 0A6
| |
Collapse
|
9
|
Raven JA, Doblin MA. Active water transport in unicellular algae: where, why, and how. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6279-6292. [PMID: 25205578 DOI: 10.1093/jxb/eru360] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The occurrence of active water transport (net transport against a free energy gradient) in photosynthetic organisms has been debated for several decades. Here, active water transport is considered in terms of its roles, where it is found, and the mechanisms by which it could occur. First there is a brief consideration of the possibility of active water transport into plant xylem in the generation of root pressure and the refilling of embolized xylem elements, and from an unsaturated atmosphere into terrestrial organisms living in habitats with limited availability of liquid water. There is then a more detailed consideration of volume and osmotic regulation in wall-less freshwater unicells, and the possibility of generation of buoyancy in marine phytoplankton such as large-celled diatoms. Calculations show that active water transport is a plausible mechanism to assist cells in upwards vertical movements, requires less energy than synthesis of low-density organic solutes, and potentially on a par with excluding certain ions from the vacuole.
Collapse
Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK School of Plant Biology, University of Western Australia, M048, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Martina A Doblin
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, NSW 2007, Australia
| |
Collapse
|