Formation of transparent exopolymer particles, TEP, from dissolved precursor material

Transparent exopolymer particles (TEP) form from polysaccharides released by many phytoplankton species, but this process by which dissolved organic matter becomes particulate is poorly understood. Here, the abiotic formation of TEP from precursors <0.2 μm and the minimum molecular weight (MW) of TEP-precursors were studied. In most samples TEP formed from material <0.2 μm (polycarbonate membrane filters, Poretics) when exposed to laminar shear in Couette flocculators. This result was unexpected as no TEP formed from material <0.45 μm (polycap capsules, Whatman) due to surface coagulation onto bubbles (Zhou et al. 1998; Limnol Oceanogr 43:1860-1871). Some TEP-precursors were able to pass through dialysis bags with a nominal pore size of 8 kDa (natural cellulose, Spektrum), although their MW is presumably 2 orders of magnitude larger, suggesting that TEP-precursors can be fibrillar. It is suggested that freshly released precursors are fibrillar and that these fibrillar precursors form larger colloids and eventually TEP within hours to days after their release.

[1]  Bruce Johnson,et al.  Coagulation on bubbles allows microbial respiration of oceanic dissolved organic carbon , 1989, Nature.

[2]  G. G. Leppard,et al.  Characterization of aquatic colloids and macromolecules. 2. Key role of physical structures on analytical results. , 1995, Environmental science & technology.

[3]  I. Sundh.  Characterization of phytoplankton extracellular products (PDOC) and their subsequent uptake by heterotrophic organisms in a mesotrophic forest lake , 1989 .

[4]  Bruce D. Johnson,et al.  Organic particle and aggregate formation resulting from the dissolution of bubbles in seawater1 , 1980 .

[5]  W. Sutcliffe,et al.  Sea surface chemistry and Langmuir circulation , 1963 .

[6]  M. A. Faust,et al.  Organic carbon release by phytoplankton: its composition and utilization by bacterioplankton , 1983 .

[7]  Y. Avnimelech,et al.  Mutual Flocculation of Algae and Clay: Evidence and Implications , 1982, Science.

[8]  A. Alldredge,et al.  Rapid formation and sedimentation of large aggregates is predictable from coagulation rates (half-lives) of transparent exopolymer particles (TEP) , 1995 .

[9]  R. Wetzel,et al.  Interaction of yellow organic acids with calcium carbonate in freshwater1 , 1973 .

[10]  U. Passow.  Distribution, size, and bacterial colonization of transparent exopolymer particles (TEP) in the ocean , 1994 .

[11]  P. Kepkay.  Particle aggregation and the biological reactivity of colloids , 1994 .

[12]  M. Orellana,et al.  Spontaneous assembly of marine dissolved organic matter into polymer gels , 1998, Nature.

[13]  A. Haug,et al.  Production of carbohydrates by the marine diatom Chaetoceros affinis var. willei (Gran) Hustedt. II. Preliminary investigation of the extracellular polysaccharide , 1972 .

[14]  U. Ekanemesang,et al.  Characterization of metal-binding bioflocculants produced by the cyanobacterial component of mixed microbial mats , 1994, Applied and environmental microbiology.

[15]  M. Shilo,et al.  Characterization of Macromolecular Flocculants Produced by Phormidium sp. Strain J-1 and by Anabaenopsis circularis PCC 6720 , 1987, Applied and environmental microbiology.

[16]  E. Balnois,et al.  Fibrillar polysaccharides in marine macromolecular organic matter as imaged by atomic force microscopy and transmission electron microscopy , 1998 .

[17]  S. Myklestad.  Production of carbohydrates by marine planktonic diatoms. I. Comparison of nine different species in culture , 1974 .

[18]  G. G. Leppard,et al.  A classification scheme for marine organic colloids in the Adriatic Sea: colloid speciation by transmission electron microscopy , 1997 .

[19]  A. Alldredge,et al.  Mass aggregation of diatom blooms: Insights from a mesocosm study , 1995 .

[20]  J. Lewin,et al.  Marine Polymers. IV Diatom Polysaccharides , 1972 .

[21]  Bruce E. Logan,et al.  The role of particulate carbohydrate exudates in the flocculation of diatom blooms , 1994 .

[22]  S. B. Moran,et al.  Short residence time of colloids in the upper ocean estimated from 238U–234Th disequilibria , 1992, Nature.

[23]  S. Myklestad.  Release of extracellular products by phytoplankton with special emphasis on polysaccharides , 1995 .

[24]  U. Passow,et al.  The role of surface‐active carbohydrates in the formation of transparent exopolymer particles by bubble adsorption of seawater , 1998 .

[25]  Alice L. Alldredge,et al.  A dye-binding assay for the spectrophotometric measurement of transparent exopolymer particles (TEP) , 1995 .

[26]  G. Riley.  ORGANIC AGGREGATES IN SEAWATER AND THE DYNAMICS OF THEIR FORMATION AND UTILIZATION , 1963 .

[27]  Serge Stoll,et al.  A Generalized Description of Aquatic Colloidal Interactions: The Three-colloidal Component Approach , 1998 .

[28]  B. Volcani,et al.  Rate of release of extracellular amino acids and carbohydrates from the marine diatom Chaetoceros affinis , 1989 .

[29]  E. Sherr.  Direct use of high molecular weight polysaccharide by heterotrophic flagellates , 1988, Nature.

[30]  Particle trajectories in a rotating cylinder: implications for aggregation incubations , 1994 .

[31]  G. G. Leppard.  The characterization of algal and microbial mucilages and their aggregates in aquatic ecosystems. , 1995, The Science of the total environment.