Daniel C. O. Thornton
Professor
Phytoplankton, diatoms, biogeochemistry, biogenic aerosol, sea spray aerosol, ice nucleating particles (INP), ice nucleation, exopolymer particles, nitrogen cycle, carbon cycle
Research
Dr. Daniel Thornton is a biologist interested in how microorganisms have played, and continue to play, a profound role in shaping how the Earth functions as a complex system. Research in the Thornton lab straddles traditional disciplinary boundaries and uses a combination of controlled laboratory experiments and observations in the natural environment. Dan Thornton’s main research interests are described below:
Production and properties of marine biogenic aerosols: The interface between ocean and atmosphere covers 71 % of the Earth’s surface, providing a large surface area from which organic matter and intact microorganisms can be thrown into the atmosphere in sea spray. Dan Thornton and his collaborators are interested in the role of marine microorganisms in producing aerosols that affect atmospheric processes. The objective of this research is to produce a mechanistic model linking the ecophysiology of phytoplankton to aerosol properties and the ability of those aerosol to act as cloud condensation nuclei (CCN) and ice nuclei particles (INP). The primary focus is the role of marine biogenic aerosol as INP as ice is often the dominant form of water in clouds, even in the tropics. Ice nucleation mechanisms are complex and poorly understood, making this process hard to parametrize in global climate models.
Dan Thornton aims to expand his research on biogenic aerosol in new directions, focusing on the ecological and biogeochemical implications of intact marine microorganisms in the atmosphere. While it is established that intact marine microorganisms are thrown into the atmosphere in sea spray, we know next to nothing about their fate. For example, how long can marine microorganisms live in the atmosphere and does aerial dispersal play a significant role in determining their distribution in the ocean? These questions were recently explored in a review paper (Alsante et. al. 2021).
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. Dan Thornton has worked on phytoplankton physiology since his first research project as an undergraduate student. He is interested in how nutrient availability affects growth and resource allocation in phytoplankton, exopolymer production, and cell death. Much of his work has focused on diatoms.
Selected Publications
* indicates that the co-author was a Student at Texas A&M University.
Biogenic Aerosol and Cloud Formation
Alsante AN*, Thornton DCO and Brooks SD (2021) Ocean Aerobiology. Frontiers in Microbiology 12:764178. doi: 10.3389/fmicb.2021.764178
Hendrickson BN*, Brooks SD, Thornton DCO, Moore RH, Crosbie E, Ziemba LD, Carlson CA, Baetge N, Mirrielees JA* and Alsante AN* (2021) Role of sea surface microlayer properties in cloud formation. Frontiers in Marine Science 7:596225. doi: 10.3389/fmars.2020.596225
Wilbourn EK*, Thornton DCO, Ott C*, Graff J, Quinn PK, Bates TS, Betha R, Russell LM, Behrenfeld MJ, Brooks SD (2020) Ice nucleation by marine aerosols over the North Atlantic Ocean in late spring. Journal of Geophysical Research: Atmospheres 125: e2019JD030913. https://doi.org/ 10.1029/2019JD030913
Brooks SD, Jickells TD, Liss PS, Thornton DCO, Zhang R (2019) Biogeochemical coupling between ocean and atmosphere – A tribute to the lifetime contribution of Robert A. Duce. Journal of the Atmospheric Sciences 76: 3289-3298 doi: 10.1175/JAS-D-18-0305.1
Brooks SD, Thornton DCO (2018) Marine aerosols and clouds. Annual Review of Marine Science 10: 289-313 doi: 10.1146/annurev-marine-121916-063148
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
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
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
Phytoplankton Physiology and Ecology
Chen J*, Guo K, Thornton DCO, Wu Y (2021) Effect of temperature on the release of transparent exopolymer particles (TEP) and aggregation by marine diatoms (Thalassiosira weissflogii and Skeletonema marinoi). Journal of the Ocean University of China 20: 1-11 https://doi.org/10.1007/s11802-021-4528-3
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
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
Rzadkowolski CE*, Thornton DCO (2012) Using laser scattering to identify diatoms and conduct aggregation experiments. European Journal of Phycology 47(1): 30-41
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
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 (2002) Diatom aggregation in the sea: mechanisms and ecological implications. European Journal of Phycology 37:149-161. doi: 10.1017/S0967026202003657
Thornton DCO (2002) Individuals, clones or groups? Phytoplankton behaviour and units of selection. Ethology, Ecology and Evolution 14:165-173
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
Exopolymers in the Ocean
Thornton DCO (2018) Coomassie stainable particles (CSP): The significance of protein exopolymer particles in the ocean. Frontiers in Marine Science 5: 206 doi: 0.3389/fmars.2018.00206
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
Thornton DCO (2009) Spatiotemporal distribution of dissolved acidic polysaccharides (dAPS) in a tidal estuary. Limnology and Oceanography 54: 1449-1460
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 (2004) Formation of transparent exopolymeric particles (TEP) from macroalgal detritus. Marine Ecology Progress Series 282: 1-12
Nitrogen and Carbon Cycling in Coastal Sediments
Kim J*, Chapman P, Rowe G, DiMarco SF, Thornton DCO (2020) Implications of different nitrogen input sources for potential production and carbon flux estimates in the coastal Gulf of Mexico (GOM) and Korean Peninsula coastal waters. Ocean Science 16:45-63. https://doi.org/10.5194/os-16-45-2020
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
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
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, 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
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
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
Dissolved Organic Matter (DOM) and Halocarbons
Gold-Bouchot G, Polis S*, Castañon LE*, Flores MP*, Alyssa Alsante AN*, Thornton DCO (2021) Chromophoric dissolved organic matter (CDOM) in a subtropical estuary (Galveston Bay, USA) and the impact of Hurricane Harvey. Environmental Science and Pollution Research https://doi.org/10.1007/s11356-021-14509-x
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
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: 3375−3382 doi: 10.1021/es505464k
Liu Y*, Yvon-Lewis SA, Thornton DCO, Butler JH, Bianchi TS, Campbell L, Hu L*, Smith RW* (2013) 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 (2013) 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
Education
Ph.D., Queen Mary, University of London, UK, 1996
B.Sc., Marine and Freshwater Biology, Queen Mary, University of London, UK, 1991
Links
Additional Information
Experience
2018 – present: Professor, Department of Oceanography, Texas A&M University
2018 – 2019: Assistant Department Head for Academics and Undergraduate Affairs
2013 - 2015: Assistant Department Head, Department of Oceanography, Texas A&M University
2010 - 2018: 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
