We report the concentration, phosphorus (P) and nitrogen (N) content, and size and chemical fractionation of fine suspended particles (0.2-100 mm) and colloids (3 kilodalton (kDa)-0.1 mm) in the surface water of Everglades wetlands along regional and P-enrichment gradients. Total suspended sediment concentrations ranged from 0.7 to 2.7 mg L21. Total particulate P concentrations increased from 0.05 mmol L21 to 0.31 mmol L21 along the P- enrichment gradient. Particles contained from 20% to 43% of total P but ,12% of total N in surface water. Dissolved (,0.2 mm) organic N contained about 90% of total N, with the 3-100-kDa colloidal size class containing the most N of any size class. The 0.45-2.7-mm size fraction held the most particulate P at all sites, whereas particulate N was most abundant in the 2.7-10-mm size class at most sites. Standard chemical fractionation of particles identified acid-hydrolyzable P as the most abundant species of particulate P, with little reactive or refractory organic P. Sequential chemical extraction revealed that about 65% of total particulate P was microbial, while about 25% was associated with humic and fulvic organic matter. The size and chemical fractionation information suggested that P-rich particles mostly consisted of suspended bacteria. Suspended particles in Everglades wetlands were small in size and had low concentrations, yet they stored a large proportion of surface-water P in intermediately reactive forms, but they held little N. Suspended particulate matter plays a large role in the cycling and transport of energy and nutrients in aquatic ecosystems. In particular, phosphorus (P) transport and reactivity are strongly associated with suspended sediment in streams and rivers (Froelich 1988; Meybeck 1982; Fox 1993). Particulate and colloidal P fractions are especially important for the transport of P from agricultural fields to streams (Heathwaite et al. 2000). A large proportion of P exported in streams is also associated with fine particulate organic matter (,1 mm; Meyer and Likens 1979). Thus, nutrient spiralling models for streams and rivers incorpo- rate the differential transport and biogeochemistry of particulate and dissolved nutrients (Webster and Patten 1979). In lakes, suspended particles and colloids (Lean 1973) and small bacterioplankton (Currie and Kalff 1984) are also very important to P cycling. Furthermore, suspended particles quickly incorporate inorganic P in