Daniel Thornton

Daniel Thornton


Biological Oceanography: Phytoplankton; Biogeochemistry; Aerosols


  (979) 845-4092

  Eller O&M 521


I am a biologist who is interested in marine microorganisms. My research centers on the role that photosynthetic microorganisms play in biogeochemical cycles. I am fascinated by the concept that microorganisms have played, and continue to play, a profound role in shaping how the Earth functions as a complex system. My work straddles traditional disciplinary boundaries and I use a combination of controlled laboratory experiments and in situ observation. Recent work has focused on the fate of organic matter fixed by phytoplankton. Conceptually, I regard this organic matter as more than ‘food’ for other organisms; it may affect processes as diverse as atmospheric cloud formation and the transport of organic matter from sunlit surface waters to the deep ocean. My main research interests are listed below:

Production of biogenic gases and aerosols: The interface between ocean and atmosphere covers 71 % of the Earth’s surface. My collaborators and I are interested in the role of marine microorganisms in producing gases and aerosols that affect atmospheric processes. Exchanges of matter and energy across the ocean-atmosphere interface affect weather and climate. For example, aerosols and the clouds that form on them are a major uncertainty in our current understanding of Earth’s radiative budget and our ability to predict future climate. See Brooks & Thornton (2018), Steiner et al. (2015), Liu et al. (2013a,b) for examples.

Physiology and ecology of phytoplankton: Phytoplankton are responsible for almost half the photosynthetic carbon fixation on Earth each year. Understanding the biology of this incredibly diverse group of organisms is essential to understand how marine ecosystems function today and to predict how they will function in the future. Phytoplankton are the ‘food source’ in marine ecosystems that provide essential ecosystem services, such as fisheries. See Thornton & Chen (2017), Chen & Thornton (2015), Thornton (2014) for examples.

Biogeochemistry of exoploymers: Exopolymers are large molecules (e.g polysaccharides and proteins) that are released into the environment by microorganisms. They play an important role in the marine carbon cycle. For example, some types of exopolymers are sticky and act as the ‘glue’ that binds together particles in the water to form marine snow. Marine snow sinks relatively rapidly from surface waters into the deep ocean, where the carbon is sequestered for hundreds to thousands of years. This process is a component of the biological carbon pump, which helps regulate the amount of carbon dioxide in the atmosphere. See Thornton & Chen (2017), Thornton et al. (2016), Thornton et al. (2007) for examples.

Benthic biogeochemistry: Marine sediments play a major role in carbon and nitrogen cycling in the ocean. For example, estuarine sediments can provide a valuable ecosystem service by removing excess biologically available nitrogen from the overlying water via the process of denitrification. See Thornton et al. (2007), Dong et al. (2000, 2002) for examples.

Precambrian microbial ecology and biogeochemistry: Microorganisms in the ocean have played a major role in shaping the Earth system over the last 3.5 billion years. The environmental conditions that we see today are a product not only a product of contemporary biogeochemical processes, but also events that have shaped the Earth over geological time. Understanding this past will help us understand how the Earth system functions today, and help us make predictions about the future of life on Earth. See Tice et al. (2011) for an example.

Selected Publications


(* indicates that the author was a Texas A&M University student)

Brooks SD, Thornton DCO (2018) Marine aerosols and clouds. Annual Review of Marine Science 10

Thornton DCO, and Chen J* (2017) Exopolymer production as a function of cell permeability and death in a diatom (Thalassiosira weissflogii) and a cyanobacterium (Synechococcus elongatus). Journal of Phycology 53: 245-260 doi: 10.1111/jpy.12470

Thornton DCO, Brooks SD and Chen J* (2016) Protein and carbohydrate exopolymer particles in the sea surface microlayer (SML). Frontiers in Marine Science 3:135. doi: 10.3389/fmars.2016.00135

Bianchi TS, Thornton DCO, Yvon-Lewis SA, King GM, Eglinton TI, Shields MR, Ward ND, Curtis J (2015) Positive priming of terrestrially-derived dissolved organic matter in a freshwater microcosm system. Geophysical Research Letters 42: 5460-5467. doi:10.1002/2015GL064765

Steiner AL, Brooks SD, Deng C*, Thornton DCO, Pendleton M, Bryant V (2015) Pollen as atmospheric cloud condensation nuclei. Geophysical Research Letters 42: 3596–3602. doi:10.1002/2015GL064060

Liu Y*, Thornton DCO, Bianchi TS, Shields MR*, Chen J*, Yvon-Lewis SA  (2015) Marine dissolved organic matter (DOM) composition drives the production and chemical speciation of brominated very short-lived substances. Environmental Science and Technology. 49: 33753382 doi: 10.1021/es505464k

Chen J*, Thornton DCO (2015) Effect of growth rate on TEP production and aggregation of Thalassiosira weissflogii. Journal of Phycology 51: 381-393. doi: 10.1111/jpy.12285

Thornton DCO (2014) Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean. European Journal of Phycology 49:  20-46. doi:10.1080/09670262.2013.875596

Deng C*, Brooks SD, Vidaurre G, Thornton DCO (2014). Using Raman microspectroscopy to determine chemical composition and mixing state of airborne marine aerosols over the Pacific Ocean. Aerosol Science and Technology 48:193-206. doi:10.1080/02786826.2013.867297

Liu Y*, Yvon-Lewis SA, Thornton DCO, Butler JH, Bianchi TS, Campbell  L, Hu L*, Smith RW* (2013a) Spatial and temporal distributions of bromoform and dibromomethane in the Atlantic Ocean and their relationship with photosynthetic biomass. Journal of Geophysical Research: Oceans 118: 1-16. doi:10.1002/jgrc.20299

Liu Y*, Yvon-Lewis SA, Thornton DCO, Campbell L, Bianchi TS (2013b) Spatial distribution of brominated very short-lived substances in the Eastern Pacific. Journal of Geophysical Research: Oceans 118: 1-11. doi:10.1002/jgrc.20183

Nunnally CC*, Rowe GT, Thornton DCO, Quigg A,  (2013) Oxygen consumption and nutrient regeneration by sediments in the Northern Gulf of Mexico Hypoxic Zone. Journal of Coastal Research – special issue 63: 84-96

Rzadkowolski CE*, Thornton DCO (2012) Using laser scattering to identify diatoms and conduct aggregation experiments. European Journal of Phycology 47(1): 30-41

Tice MM, Thornton DCO, Pope MC, Olszewski TD, Gong J* (2011) Archean microbial mat communities. Annual Review of Earth and Planetary Sciences 39: 297-319

Thornton DCO, Kopac SM, Long RA (2010) Production and enzymatic hydrolysis of carbohydrates in intertidal sediment.   Aquatic Microbial Ecology 60: 109-125

Hiranuma N*, Brooks SD, Thornton DCO, Auvermann BW (2010) Atmospheric ammonia mixing ratios at an open-air cattle feeding facility.  Journal of the Air & Waste Management Association 60: 210-218

Thornton DCO (2009) Spatiotemporal distribution of dissolved acidic polysaccharides (dAPS) in a tidal estuary. Limnology and Oceanography 54: 1449-1460

Thornton DCO (2009) Effect of low pH on carbohydrate production by a marine planktonic diatom (Chaetoceros muelleri). Research Letters in Ecology, Article ID 105901, doi:10.1155/2009/105901

Thornton DCO, Visser LA* (2009) Measurement of acid polysaccharides (APS) associated with microphytobenthos in salt marsh sediments. Aquatic Microbial Ecology 54: 185-198

Thornton DCO, Fejes EM*, DiMarco SF, Clancy KM* (2007) Measurement of acid polysaccharides (APS) in marine and freshwater samples using alcian blue. Limnology and Oceanography: Methods 5: 73-87

Thornton DCO, Dong LF, Underwood GJC, Nedwell DB (2007) Sediment-water nutrient exchange and nitrogen budgets in the Colne Estuary. Marine Ecology Progress Series 337: 63-77

Patel D, Thake B, Thornton DCO (2005) Effect of light and turbulent mixing on the growth of Skeletonema costatum (Bacillariophyceae).   Marine Biology 146: 633-644

Thornton DCO (2004) Formation of transparent exopolymeric particles (TEP) from macroalgal detritus.  Marine Ecology Progress Series 282: 1-12

Thornton DCO (2002) Diatom aggregation in the sea: mechanisms and ecological implications. European Journal of Phycology  37:149-161. doi: 10.1017/S0967026202003657

Thornton DCO, Dong LF, Underwood GJC, Nedwell DB (2002) Factors affecting microphytobenthic biomass, species composition and production in the Colne estuary (UK). Aquatic Microbial Ecology 27:285-300

Dong LF, Nedwell DB, Underwood GJC, Thornton DCO, Rusmuna I  (2002) Nitrous oxide formation in estuaries: the central role of nitrite. Applied and Environmental Microbiology 68:1240-1249

Thornton DCO (2002) Individuals, clones or groups? Phytoplankton behaviour and units of selection. Ethology, Ecology and Evolution 14:165-173

Dong LF, Thornton DCO, Underwood GJC, Nedwell DB (2000) Denitrification in the sediments of the Colne estuary, England. Marine Ecology Progress Series 203: 109-122

Thornton DCO, Underwood GJC, Nedwell DB (1999) Effect of light and emersion period on the exchange of ammonium across the estuarine sediment-water interface. Marine Ecology Progress Series 184: 11-20

Thornton DCO, Santillo D, Thake B (1999)   Prediction of sporadic mucilaginous algal blooms in the Northern Adriatic Sea. Marine Pollution Bulletin 38(10): 891-898

Thornton DCO (1999) Phytoplankton mucilage in coastal waters: A dispersal mechanism in a front dominated system? Ethology Ecology and Evolution 11(2): 179-185

Thornton DCO, Thake B (1998) Effect of temperature on the aggregation of Skeletonema costatum (Bacillariophyceae) and the implication for carbon flux in coastal waters. Marine Ecology Progress Series 174: 223-237


Ph.D., Queen Mary, University of London, UK, 1996

B.Sc., Marine and Freshwater Biology, Queen Mary, University of London, UK, 1991

Additional Information


  • 2013 - 2015: Assistant Department Head, Department of Oceanography, Texas A&M University
  • 2010 - present: Associate Professor, Department of Oceanography, Texas A&M University
  • 2004 - 2010: Assistant Professor, Department of Oceanography, Texas A&M University
  • 2003: Research Fellow, Wrigley Institute for Environmental Studies, University of Southern California
  • 2000 - 2002: Research Fellow, Ecology Centre, University of Sunderland, UK
  • 1996 - 1999: Senior Research Officer, Department of Biological Sciences, University of Essex, UK

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