The University of Southampton
University of Southampton Institutional Repository

Investigating reasons for the growth and survival of the dinoflagellate genus Neoceratium in oligotrophic subtropical gyres

Investigating reasons for the growth and survival of the dinoflagellate genus Neoceratium in oligotrophic subtropical gyres
Investigating reasons for the growth and survival of the dinoflagellate genus Neoceratium in oligotrophic subtropical gyres
The dinoflagellate Neoceratium is frequently observed in oligotrophic subtropical gyres (OSGs) where major inorganic nutrients such as nitrogen and phosphorus are depleted in the surface waters. In Chapter 2, continuous plankton recorder (CPR) data demonstrate that Neoceratium inhabit surface waters of the North Atlantic subtropical gyre (NAG) throughout the year. The presence of Neoceratium in surface waters contrasts with the fact that nutrients are severely depleted in the surface 100 to 130 m. In Chapter 3, it is shown that Neoceratium cannot grow when exposed to low nutrient concentrations comparable to those found in surface waters of OSGs. However, cells are able to survive and re-establish growth after a maximum of >3 weeks of “nutrient starvation”, with signs of stress becoming noticeable after 10 days. In Chapter 4, nutrient ratios in large areas of surface waters of OSGs in the Atlantic are shown to be favourable to mixotrophy (86 % of sites in the North and South Atlantic OSGs). It is estimated that 0.01 to 0.44 ciliates per day would need to be ingested for Neoceratium to survive in these waters. In Chapter 5, growth was only observed when cells were exposed to a range of irradiances (6 to 60 ?mol quanta m-2 s-1), above 22 ?mol quanta m-2 s-1; an irradiance that is typically only found 15 to 22 metres above the nutricline at midday, implying that VM would be required to access the nutricline. A mechanism for VM in OSGs is suggested whereby vertical movement is triggered by phosphate-limitation of cells. In Chapter 6, the thesis concludes with a conceptual model to explain how a number of the above findings likely interact to enable Neoceratium to successfully survive and grow in OSGs.
Aldridge, David
08ee4808-5714-4c0e-9115-10b3defb6acc
Aldridge, David
08ee4808-5714-4c0e-9115-10b3defb6acc
Zubkov, Michail
b1dfb3a0-bcff-430c-9031-358a22b50743

Aldridge, David (2014) Investigating reasons for the growth and survival of the dinoflagellate genus Neoceratium in oligotrophic subtropical gyres. University of Southampton, Ocean and Earth Science, Doctoral Thesis, 181pp.

Record type: Thesis (Doctoral)

Abstract

The dinoflagellate Neoceratium is frequently observed in oligotrophic subtropical gyres (OSGs) where major inorganic nutrients such as nitrogen and phosphorus are depleted in the surface waters. In Chapter 2, continuous plankton recorder (CPR) data demonstrate that Neoceratium inhabit surface waters of the North Atlantic subtropical gyre (NAG) throughout the year. The presence of Neoceratium in surface waters contrasts with the fact that nutrients are severely depleted in the surface 100 to 130 m. In Chapter 3, it is shown that Neoceratium cannot grow when exposed to low nutrient concentrations comparable to those found in surface waters of OSGs. However, cells are able to survive and re-establish growth after a maximum of >3 weeks of “nutrient starvation”, with signs of stress becoming noticeable after 10 days. In Chapter 4, nutrient ratios in large areas of surface waters of OSGs in the Atlantic are shown to be favourable to mixotrophy (86 % of sites in the North and South Atlantic OSGs). It is estimated that 0.01 to 0.44 ciliates per day would need to be ingested for Neoceratium to survive in these waters. In Chapter 5, growth was only observed when cells were exposed to a range of irradiances (6 to 60 ?mol quanta m-2 s-1), above 22 ?mol quanta m-2 s-1; an irradiance that is typically only found 15 to 22 metres above the nutricline at midday, implying that VM would be required to access the nutricline. A mechanism for VM in OSGs is suggested whereby vertical movement is triggered by phosphate-limitation of cells. In Chapter 6, the thesis concludes with a conceptual model to explain how a number of the above findings likely interact to enable Neoceratium to successfully survive and grow in OSGs.

PDF
FINAL THESIS - David Aldridge.pdf - Other
Download (4MB)

More information

Published date: June 2014
Organisations: University of Southampton, Ocean and Earth Science

Identifiers

Local EPrints ID: 367218
URI: http://eprints.soton.ac.uk/id/eprint/367218
PURE UUID: 4b973c55-cc22-4af4-9240-30d622c5cbe7

Catalogue record

Date deposited: 30 Jul 2014 13:45
Last modified: 18 Jul 2017 02:02

Export record

Contributors

Author: David Aldridge
Thesis advisor: Michail Zubkov

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×