Ron Kiene

Professor Department of Marine Sciences
University of South Alabama
LSCB-25
Mobile AL 36688
also
Senior Marine Scientist III
Dauphin Island Sea Lab

Ph.D., 1987, SUNY Stony Brook

Email

Research Interests

My research focuses on the role of microorganisms in the cycling of organic matter and important elements such as sulfur and nitrogen in aquatic systems.

A major focus of my research program is the biogeochemical cycling of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) in the marine water column. We carry out this research in local waters but also on oceanographic cruises all over the world.  This field continues to broaden as we have discovered new and important roles for DMSP and its degradation products in the marine ecosystem.  DMSP is produced by many, but not all, marine algae who use it as an osmotic solute and potentially an antioxidant.  DMSP is degraded by microorganisms to volatile DMS which is a major source of sulfur to the atmosphere.  This input of DMS to the atmosphere significantly affects atmospheric chemistry (especially the pH of precipitation) and also the global climate system because DMS is oxidized to sulfate aerosols (tiny crystals of salt).  Sulfate aerosols affect climate by directly reflecting solar radiation back to space and by serving as cloud condensation nuclei, which in turn affect how clouds reflect solar radiation.

Here are some brief highlights of ongoing projects.

The role of DMSP as an antioxidant in marine algae – With funding from the NSF Biological Oceanography program we are testing the hypothesis that DMSP and its degradation products are important scavengers of reactive oxygen species in cells of marine algae.  We are using pure cultures of marine phytoplankton as well as natural populations in seawater to study the physiological responses of the algae to oxidative stresses.  One of the responses we are particularly interested in is the algal degradation of DMSP to DMS, catalyzed by DMSP lyase enzymes.  We are examining the activity and regulation of DMSP lyase in the oxidative stress physiology of the phytoplankton.  With separate funding from EPA we are also examining the oxidative stress physiology of the marsh grass Spartina alterniflora, another DMSP producer.   

Biogeochemical cycling of DMSP and DMS in the Ross Sea, Antarctica – The Ross Sea experiences a spectacular bloom of phytoplankton beginning in the austral spring and extending into the austral summer.  This bloom is composed mainly of Phaeocystis antarctica, a prymnesiophyte alga that produces large amounts of DMSP. Previous studies have documented extremely high concentrations of DMS in the Ross Sea, but no process studies have been carried out.  With funding from the NSF Office of Polar Programs, we will be using  an experimental approach and field sampling to examine the factors which control DMSP and DMS production in these icy cold waters. The 35S-DMSP and 35S-DMS tracer methods that we have developed provide us with powerful tools to study DMSP/DMS cycling processes under extreme conditions.  We are particularly interested in the impact of solar radiation (both visible and ultraviolet) on the algal and bacterial communities that are responsible for cycling DMSP/DMS.  Solar UV radiation is an important factor in the Ross Sea during the early bloom development because this area is within the Antarctic Ozone Hole.  Several cruises to Antarctic waters are planned for the coming years.  

The biocomplexity of the global DMS cycle – The biogeochemical cycle of DMS in the ocean involves many different types of organisms (algae, bacteria, viruses, grazers) interacting in a complex web of ecological, processes, all of which depend greatly on the geophysical and biophysical conditions experienced by the plankton community.  In turn, DMS emissions to the atmosphere can have an enormous impact on atmospheric chemistry and climate with potential for feedbacks on the plankton communities that produce DMSP and DMS.  We are funded by the NSF Biocomplexity program to work with other DMS specialists, food web modelers and climate modelers to advance understanding of how the DMS cycle functions and how it responds to forcings such as temperature, visible light, ultraviolet radiation, nutrients, water column mixing depths and other factors.  In addition to laboratory components, this project has two major field components.  The first will be a month-long cruise to the Sargasso Sea near the Bermuda Atlantic Time Series (BATS) station to investigate the late summer “DMS paradox”, a period of high DMS concentrations when plankton biomass is extremely low.  The second field study will be an extended time series and experimental investigation of DMS cycling in the productive waters near the Antarctic Palmer Peninsula.

Microbial ecology and carbon cycling in estuaries -  With funding from the US EPA we have been studying the trophic dynamics in the microbial food web of Mobile Bay, a large shallow estuary on the US Gulf Coast. We are measuring the biomass, production and growth efficiency of bacteria in the estuary.  Field and laboratory experiments are being carried out to test how temporal and spatial variations in sediment resuspension and riverine DOC inputs influence the role of bacteria the trophic transfers within the Bay ecosystem. The trophic status of the Bay (heterotrophic vs. autotrophic) is being assessed to determine how efficient the system is at processing nutrients and carbon and in transferring energy up to the fish forage base.

Selected Publications

Zubkov, M, L. J. Linn, R. Amann and R. P. Kiene. Temporal patterns of biological dimethylsulfide (DMS) consumption during laboratory-induced phytoplankton bloom cycles.  Marine Ecology Progress Series. In Press.

Harada, H, M-A. Rouse, W. Sunda and R. P. Kiene.  Latitudinal and vertical distributions of particle-associated DMSP lyase activity in the western North Atlantic Ocean.  Can. J. Fish. Aquat. Sci. In Press.  

Malmstrom, R R., R. P. Kiene and D. L. Kirchman.  Identification and enumeration of marine bacteria assimilating dimethylsulfoniopropionate (DMSP) in the north Atlantic and Gulf of Mexico.  Limnology and Oceanography.  In Press.

Stets, E G, M. E. Hines and R. P. Kiene.  2004.  Thiol methylation potential in anoxic, low pH wetland sediments and its relationship dimethylsulfide production and organic carbon cycling.  FEMS Microbiology Ecology. 47: 1-11.

Toole, D.A.,  D. J. Kieber, R. P. Kiene, D. A. Siegel, and N.B. Nelson.  2003.  Photolysis and the dimethylsulfide (DMS) summer paradox in the Sargasso Sea.  Limnol. Oceanogr. 48: 1088-1100.

Moran, M. A., J. M. González, and R. P. Kiene.  2003.  Linking a bacterial taxon to organic sulfur cycling in the sea: studies of the marine Roseobacter group.  Geomicrobiology Journal.  20: 375-388.

Sunda, W., D. J. Kieber, R. P. Kiene and S. Huntsman.  2002.  An antioxidant function for DMSP in marine algae.  Nature 418: 317-320.              

Zubkov, M. V., B. M. Fuchs, S. D. Archer, R. P. Kiene, R. Amann and P. H. Burkill.  2002.  Rapid turnover of dissolved DMS and DMSP by defined bacterioplankton communities in the stratified euphotic zone of the North Sea.  Deep-Sea Res.Part  II. 49: 3017-3038.

Hines, M. E., K. N. Duddleston and R. P. Kiene.  2001. Carbon flow to acetate and C1 compounds in high latitude wetlands.  Geophysical Res. Lett. 28: 4251-4254.

Zubkov, M, B. M. Fuchs, S.D. Archer, R. P. Kiene, R. Amann and P. Burkhill.  2001.  Linking the composition of bacterioplankton to rapid turnover of dissolved dimethylsulphoniopropionate in an algal bloom in the North Sea.  Environ. Microbiol. 3: 304-311.

Kiene, R. P. and L. Linn.  2000.  The fate of dissolved dimethylsulfoniopropionate (DMSP) in seawater:  Tracer studies using 35S-DMSP.  Geochim. Cosmochim. Acta.  64: 797-2810. 

Kiene, R. P.  and L. J. Linn.  2000.  Turnover of dissolved DMSP and its relationship with bacterial production in the Gulf of Mexico.  Limnol. Oceanogr. 45(4): 849-861. 

Kiene, R. P., L. J. Linn and J. A. Bruton. 2000.  New and important roles for DMSP in marine microbial communities.  J. Sea Res. 43: 209-224.

Books Edited

Kiene, R.P., P.T. Visscher, G.O. Kirst and M.D. Keller (Eds.). 1996. Biological and Environmental Chemistry of DMSP and related sulfonium compounds. Plenum Publishing Corp., New York 430p.

Selected Current Research Grants –

National Science Foundation – Polar Programs-Antarctic Biology and Medicine.  Impact of solar radiation and nutrients on biogeochemical cycling of DMSP and DMS in the Ross Sea, Antarctica.  (with David Kieber, SUNY ESF).

National Science Foundation – Biocomplexity in the Environment.  Complex molecular to global interactions and feedbacks in the marine DMS cycle.  (with Patricia Matrai, Bigelow Laboratory, and several other PI’s).

National Science Foundation – Biological Oceanography.  Production and dynamics of DMSP and related compounds in response to oxidative stress in marine phytoplankton.  (with David Kieber, SUNY ESF).

National Science Foundation – Microbial genetics.  A genomic approach t sulfur biotransformations in the ocean: the genome sequence of a marine Roseobacter. $51,118, sub-contract from Univ. Georgia, under grant to Mary Ann Moran. 

Environmental Protection Agency – Alabama Center for Estuarine Studies. Oxidative stress protection by dimethylsulfoniopropionate(DMSP) in Spartina alterniflora.