Size, composition and distribution of particles related to wind induced resuspension in a shallow tropical lagoon

Tlic s i x . coniposition and distribution of p;irticlcs in the water column wcrc surveyed i n ;I shiillow iirc;i ( I ni depth) of ;I tropicd Iiigoon (CStc d’Ivoire) during ;I scqucncc of wind-induccd rcsuspcnsion. \Viiter s;iniplcs wcrc collected hourly near the surf;lcc during one tidal cyclc. Thrcc c1i;ir;tctcristic periods wcrc distinguishcd: n c;ilni period with low wind spccd (iivcriigc I .Z ni s-’I). ;I windy period with wind spccd >3 i11 s-’ (riingc bctwccn 4 ;ind 0 m s-I) inducing scdimciii rcsuspcnsion ;ind ;I rcl;ix;ition period during tlic dccrc;isc of wind velocity. I‘roni the ;innlysis of scvcr;ii p;ir;inictcrs (pnrticlc sizc iiiitl voltinic. Ixictcria. pico;ind ii;inopIiyropl;ili~toii. ciliiitcs a n d dctritus), scdiiiicnt rcsuspcnsion c;iuscd ;I regular injcction o f p;irticlcs f r o m tlic lwd. The finest particles ( 15-0 pni: clilorophytcs such ;is Clllorcllr spp.. picocyano1)actcri;i such :IS .S~~rrcr/rorocrr~s) were ttic first to be iiffcctcd by wind-induccd turbulence. whereas large p;irticlcs (6-12 pi: diatoms. cyiinohx1cri:i such ;IS Lprr~hicr spp.) wcrc dispcrscd i n t o the water column ;it the highest wind spccd. Thc fate of rlic different scston components differed according to thcir sizc. Therefore. wind-induccd rcsuspcnsion could greatly influence the food wch orgiiniz;ition through tlic quantity. qwility and sizc ,of cdihlc piirticlcs ;iviiil;ihlc ;it ;I given tinic. ’I