Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Phenotypic evolution and adaptive strategies in marine phytoplankton (Coccolithophores)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Coccolithophores are biogeochemically important marine algae that interact with the carbon cycle through photosynthesis (CO2 sink), calcification (CO2 source) and burial of carbon into oceanic sediments. The group is considered susceptible to the ongoing climate perturbations, in particular to ocean acidification, temperature increase and nutrient limitation. The aim of this thesis was to investigate the adaptation of coccolithophores to environmental change, with the focus on temperature stress and nutrient limitation. The research was conducted in frame of three approaches: experiments testing the physiological response of coccolithophore species Helicosphaera carteri and Coccolithus pelagicus to phosphorus limitation, field studies on coccolithophore life-cycles with a method comparison and an investigation of the phenotypic evolution of the coccolithophore genus Helicosphaera over the past 15 Ma. Experimental results show that the physiology and morphology of large coccolithophores are sensitive to phosphorus limitation, and that the adaptation to low-nutrient conditions can lead to a decrease in calcification rates. Field studies have contributed to our understanding of coccolithophore life cycles, revealing complex ecological patterns within the Mediterranean community which are seemingly regulated by seasonal, temperature-driven environment changes. In addition, the high-throughput sequencing (HTS) molecular method was shown to provide overall good representation of coccolithophore community composition. Finally, the study on Helicosphaera evolution showed that adaptation to decreasing CO2 in higher latitudes involved cell and coccolith size decrease, whereas the adaptation in tropical ecosystems also included a physiological decrease in calcification rates in response to nutrient limitation. This thesis advanced our understanding of coccolithophore adaptive strategies and will improve our predictions on the fate of the group under ongoing climate change.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. , 54 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1427
Keyword [en]
Coccolithophores, Life-Cycle, Phytoplankton, Nutrient limitation, Temperature, Microscopy, High-throughput sequencing, Taxonomy
National Category
Evolutionary Biology Environmental Sciences
Identifiers
URN: urn:nbn:se:uu:diva-302903ISBN: 978-91-554-9689-0 (print)OAI: oai:DiVA.org:uu-302903DiVA: diva2:968875
Public defence
2016-10-28, Hambergsalen, Department of Earth Sciences, Villavägen 16, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2016-10-07 Created: 2016-09-12 Last updated: 2016-10-11
List of papers
1. Eco-physiological adaptation shapes the response of calcifying algae to nutrient limitation
Open this publication in new window or tab >>Eco-physiological adaptation shapes the response of calcifying algae to nutrient limitation
2015 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, 16499Article in journal (Refereed) Published
Abstract [en]

The steady increase in global ocean temperature will most likely lead to nutrient limitation in the photic zone. This will impact the physiology of marine algae, including the globally important calcifying coccolithophores. Understanding their adaptive patterns is essential for modelling carbon production in a low-nutrient ocean. We investigated the physiology of Helicosphaera carteri, a representative of the abundant but under-investigated flagellated functional group of coccolithophores. Two strains isolated from contrasting nutrient regimes (South Atlantic and Mediterranean Sea) were grown in phosphorus-replete and phosphorus-limited batch cultures. While growing exponentially in a phosphorus-replete medium, the Mediterranean strain exhibited on average 24% lower growth rate, 36% larger coccosphere volume and 21% lower particulate inorganic carbon (PIC) production than the Atlantic strain. Under phosphorus limitation, the same strain was capable of reaching a 2.6 times higher cell density than the Atlantic strain due to lower phosphorus requirements. These results suggest that local physiological adaptation can define the performance of this species under nutrient limitation.

National Category
Ecology Cell Biology Evolutionary Biology Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-253354 (URN)10.1038/srep16499 (DOI)000364487200001 ()26560531 (PubMedID)
Funder
Knut and Alice Wallenberg FoundationThe Royal Swedish Academy of Sciences
Available from: 2015-05-26 Created: 2015-05-26 Last updated: 2017-12-04Bibliographically approved
2. High temperature decreases the PIC/POC ratio and increases phosphorus requirements in Coccolithus pelagicus (Haptophyta)
Open this publication in new window or tab >>High temperature decreases the PIC/POC ratio and increases phosphorus requirements in Coccolithus pelagicus (Haptophyta)
Show others...
2014 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 11, 3531-3545 p.Article in journal (Refereed) Published
Abstract [en]

Rising ocean temperatures will likely increase stratification of the water column and reduce nutrient input into the photic zone. This will increase the likelihood of nutrient limitation in marine microalgae, leading to changes in the abundance and composition of phytoplankton communities, which in turn will affect global biogeochemical cycles. Calcifying algae, such as coccolithophores, influence the carbon cycle by fixing CO2 into particulate organic carbon through photosynthesis (POC production) and into particulate inorganic carbon through calcification (PIC production). As calcification produces a net release of CO2, the ratio of PIC to POC production determines whether coccolithophores act as a source (high PIC / POC) or a sink (low PIC / POC) of atmospheric CO2. We studied the effect of phosphorus (P-) limitation and high temperature on the physiology and the PIC / POC ratio of two subspecies of Coccolithus pelagicus. This large and heavily calcified species is a major contributor to calcite export from the photic zone into deep-sea reservoirs. Phosphorus limitation did not influence exponential growth rates in either subspecies, but P-limited cells had significantly lower cellular P-content. One of the subspecies was subjected to a 5 °C temperature increase from 10 °C to 15 °C, which did not affect exponential growth rates either, but nearly doubled cellular P-content under both high and low phosphate availability. This temperature increase reduced the PIC / POC ratio by 40–60%, whereas the PIC / POC ratio did not differ between P-limited and nutrient-replete cultures when the subspecies were grown near their respective isolation temperature. Both P-limitation and elevated temperature significantly increased coccolith malformations. Our results suggest that a temperature increase may intensify P-limitation due to a higher P-requirement to maintain growth and POC production rates, possibly reducing abundances in a warmer ocean. Under such a scenario C. pelagicus may decrease its calcification rate relative to photosynthesis, thus favouring CO2 sequestration over release. It seems unlikely that P-limitation by itself causes changes in the PIC / POC ratio in this species.

Keyword
coccolithophores, culture experiments, phosphate limitation, calcification
National Category
Natural Sciences
Research subject
Biology; Earth Science with specialization in Environmental Analysis
Identifiers
urn:nbn:se:uu:diva-220830 (URN)10.5194/bg-11-3531-2014 (DOI)000339265800008 ()
Available from: 2014-03-20 Created: 2014-03-20 Last updated: 2017-12-05Bibliographically approved
3. Phosphorus availability modifies carbon production in Coccolithus pelagicus (Haptophyta)
Open this publication in new window or tab >>Phosphorus availability modifies carbon production in Coccolithus pelagicus (Haptophyta)
Show others...
2015 (English)In: Journal of Experimental Marine Biology and Ecology, ISSN 0022-0981, E-ISSN 1879-1697, Vol. 472, 24-31 p.Article in journal (Refereed) Published
Abstract [en]

Abstract The coccolithophore Coccolithus pelagicus (Wallich) Schiller fixes CO2 into particulate organic carbon (POC) through photosynthesis and into particulate inorganic carbon (PIC) in the form of calcite. To examine the role of phosphorus (P) availability in the production of POC and PIC, C. pelagicus subsp. braarudii (Gaarder) Geisen et al. was grown in semi-continuous cultures at three initial phosphate concentrations (P-replete, 1, and 0.5 μM [P]). Reduced P-availability (1 and 0.5 μM [P]) decreased POC production, while PIC production only decreased when phosphate concentrations became growth limiting (0.5 μM [P]). This decrease has not been observed previously in batch cultures, highlighting the inadequacy of the batch culture approach with regard to determining carbon production. The reduction in growth rate by 50% at 0.5 μM [P] was accompanied by a doubling in cell volume (and POC). PIC production was halved, resulting in a lowered PIC to POC ratio. The average number of coccoliths per cell (and PIC content) remained the same among treatments, despite the significant change in cell size. Our data suggest that POC production in C. pelagicus is more sensitive towards a moderate reduction in phosphorus availability than PIC production. Once phosphorus availability limits cell division, however, phosphorus resources are invested into POC rather than PIC production. This reduces cell density and sinking rates, indicating that coccoliths do not act as ballast for reaching deeper nutrient-rich layers under nutrient limitation.

Keyword
Calcification, Carbon production, Coccolithus pelagicus, Phosphorus limitation, Semi-continuous culture
National Category
Microbiology Cell Biology
Identifiers
urn:nbn:se:uu:diva-301334 (URN)
Available from: 2016-08-19 Created: 2016-08-19 Last updated: 2017-11-28
4. Observations on the life cycle and ecology of Acanthoica quattrospina Lohmann from a Mediterranean estuary
Open this publication in new window or tab >>Observations on the life cycle and ecology of Acanthoica quattrospina Lohmann from a Mediterranean estuary
2014 (English)In: Journal of Nannoplankton Research, ISSN 1210-8049, Vol. 34, no SI, 49-56 p.Article in journal (Refereed) Published
National Category
Ecology Biological Systematics
Identifiers
urn:nbn:se:uu:diva-253353 (URN)
Conference
INA Workshop on Extant Coccolithophores research
Available from: 2015-05-26 Created: 2015-05-26 Last updated: 2016-09-13Bibliographically approved
5. Coccolithophore life-cycle dynamics in a coastal Mediterranean ecosystem: seasonality and species-specific patterns
Open this publication in new window or tab >>Coccolithophore life-cycle dynamics in a coastal Mediterranean ecosystem: seasonality and species-specific patterns
2016 (English)In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 38, no 5, 1178-1193 p.Article in journal (Refereed) Epub ahead of print
Abstract [en]

Coccolithophores (calcifying haptophyte algae) commonly exhibit a heteromorphic life cycle, alternating between morphologically distinct heterococcolith (diploid) and holococcolith (haploid) phases. The prevalence of each life phase in a coccolithophore community defines its overall ecological and biogeochemical performance due to differences in physiology, biomass and calcification. The main drivers of life-cycle dynamics and ecological preferences of the two life-phases are still unclear and field data of high taxonomic resolution are needed. We investigated the distribution and abundance patterns of the life-phases of 14 coccolithophore species. The study was conducted along the strong environmental gradients of the Krka River estuary (Eastern Adriatic Sea) during winter (February) and summer (July) 2013. The results reveal characteristic life-phase seasonality with an overall dominance of the heterococcolith phase during winter and a holococcolith phase during summer. However, we also detected exceptions to the strictly seasonal patterns as well as species-specific ecological preferences. Our findings provide new insights into coccolithophore life-phase dynamics in the Mediterranean Sea that will further advance the understanding of ecology and evolution of the group.

National Category
Earth and Related Environmental Sciences Biological Sciences
Identifiers
urn:nbn:se:uu:diva-302897 (URN)10.1093/plankt/fbw061 (DOI)000384135000004 ()
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2017-11-21Bibliographically approved
6. Haptophyte diversity and vertical distribution explored by 18S and 28S ribosomal RNA gene metabarcoding and scanning electron microscopy
Open this publication in new window or tab >>Haptophyte diversity and vertical distribution explored by 18S and 28S ribosomal RNA gene metabarcoding and scanning electron microscopy
2017 (English)In: Journal of Eukaryotic Microbiology, ISSN 1066-5234, E-ISSN 1550-7408, Vol. 64, no 4, 514-532 p.Article in journal (Refereed) Published
Abstract [en]

Haptophyta encompasses more than 300 species of mostly marine pico- and nanoplanktonic flagellates. Our aims were to investigate the Oslofjorden haptophyte diversity and vertical distribution by metabarcoding, and to improve the approach to study haptophyte community composition, richness and proportional abundance by comparing two rRNA markers and scanning electron microscopy (SEM). Samples were collected in August 2013 at the Outer Oslofjorden, Norway. Total RNA/cDNA was amplified by haptophyte-specific primers targeting the V4 region of the 18S, and the D1-D2 region of the 28S rRNA. Taxonomy was assigned using curated haptophyte reference databases and phylogenetic analyses. Both marker genes showed Chrysochromulinaceae and Prymnesiaceae to be the families with highest number of Operational Taxonomic Units (OTUs), as well as proportional abundance. The 18S rRNA data setalso contained OTUs assigned to eight supported and defined clades consisting of environmental sequences only, possibly representing novel lineages from family to class. We also recorded new species for the area. Comparing coccolithophores by SEM with metabarcoding shows a good correspondence with the 18S rRNA gene proportional abundances. Our results contribute to link morphological and molecular data and 28S to 18S rRNA gene sequences of haptophytes without cultured representatives, and to improve metabarcoding methodology.

Keyword
Abundance, coccolithophores, high-throughput sequencing, Oslofjorden, phylogeny, richness
National Category
Biological Sciences Biological Systematics Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-302898 (URN)10.1111/jeu.12388 (DOI)000406102000010 ()27973742 (PubMedID)
Note

De två första författarna delar förstaförfattarskapet.

Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2017-11-02Bibliographically approved
7. Nutrient availability modified the evolution of calcifying algae during the past 15 million years
Open this publication in new window or tab >>Nutrient availability modified the evolution of calcifying algae during the past 15 million years
(English)Manuscript (preprint) (Other academic)
National Category
Evolutionary Biology Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-302900 (URN)
External cooperation:
Available from: 2016-09-12 Created: 2016-09-12 Last updated: 2016-09-13

Open Access in DiVA

fulltext(1725 kB)245 downloads
File information
File name FULLTEXT01.pdfFile size 1725 kBChecksum SHA-512
76ab22bc5d966bc651c68d103e70bc68538127c309c2de382198b595b19ce6b51ef5286c0aa08d9e0062087199ff2ed34d9f1cbde665c3ee0c8de9c80521ee40
Type fulltextMimetype application/pdf
Buy this publication >>

Search in DiVA

By author/editor
Šupraha, Luka
By organisation
Palaeobiology
Evolutionary BiologyEnvironmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 245 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1519 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf