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[Extract] Studies of the fate of fine sediment at the mouth of muddy rivers have revealed that the sediment generally falls rapidly out of suspension and does not follow the brackish water in the river plume. The Amazon River plume is a well-documented example (Geyer et a1. 1991; Kineke et al 1996). This observation has been attributed to the formation in coastal waters of large flocs, also called micro-aggregates, that accelerate the settling of the fine sediment. Such flocs have also been found in the Dutch coastal zone (Eisma et a1. 1990), the North Carolina inner shelf (Wells 1989) and the Amazon shelf (Berhane et al. 1997). These floes can exceed many hundreds, sometimes thousands, of µm in diameter. Their settling velocity is thus much higher than that of the floes usual1y found in very turbid estuaries, these flocs are seldom much larger than 100 µm in diameter (Gibbs 1985; Gibbs et at 1989; Wolanski and Gibbs 1995). The formation of micro-aggregates is thus important in controlling the fate of riverine sediment The processes generating the micro-aggregates have been little studied, though it has been speculated they were biological in nature (Cloern et al. 1983; Nelsen and Trefry 1986; Monaco et al. 1990). Recently Zimmerman and Kausch (1996) and Ayukai and Wolanski (1997) documented the planktonic origin of these micro-aggregates in respectively the Elbe River estuary and the Fly River plume in Torres Strait, Australia. These micro-aggregates essentially formed a mud-affected “marine snow “. The marine snow was previously documented only for the open ocean where there was negligible sediment in suspension (Alldredge and Silver 1988; Alldredge et al. 1993), In the Fly River, plume microphotographs of the undisturbed flocs (Ayukai and Wolanski 1997) revealed that the fine sediment particles that have escaped trapping in the estuary attach themselves to the sticky surface of the marine snow. The resulting micro-aggregates settle out of suspension near the mouth of the Fly River while the plume extends tens of kilometers further offshore. In the case of the Fly River the extremely high turbidity in the estuary prevents significant plankton growth in the estuary itself where the flocs are small (typically

An improved method for sequencing human genomic DNA amplified by the polymerase chain reaction (PCR) procedure is described. The portion of the genome investigated is the 383 nucleotide-long exon 2 of the human antithrombin III gene. Incorporation of the analogue of dGTP, 7-deaza-2′-deoxyguanosine-5′-triphosphate, during the amplification of exon 2 by PCR allowed for the elimination of recurrent artifacts obtained during sequencing of the amplified ONA by the dideox-yribonucleotide chain termination method.