## ABSTRACT

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Tidal Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Water Flow through the Forest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Mixing, Flushing, and Seed Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Waves in Mangroves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Maintenance of Biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Sedimentation and Sea-Level Rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Fine Sediment as a Tracer for Mixing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Groundwater Flow and Bioturbation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Recruitment of Prawn Larvae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

There are two dominant types of mangrove swamps, the riverine type that fringes rivers and tidal creeks, and the open water type that is directly exposed by waves (Lugo & Snedaker, 1974). The former type is the most common, with a strip of mangroves typically 50 to 300 m wide fringing the tidal creek or river on either side. Such an example is the 5-km-long mangrove-fringed Merbok River estuary in Malaysia (Figure 1). The second type is generally present only in embayments protected by shallow reefs and mud or sand banks that allow wave attack only around high tide. Missionary Bay in Australia (Figure 1b) is a typical example of an extensive mangrove swamp that is protected from the prevailing tradewinds but nevertheless is occasionally attacked by waves in the monsoon season. Along coral reefs, mangroves

can also be present and are protected from excessive wave attack by waves breaking on the fringing reefs. Along muddy coasts a strip of mangroves, typically a few hundred meters wide, can fringe the open coast, and these are very frequently under wave attack; nevertheless, they survive. Such is the case of the Thuy Hai coast of the Gulf of Tonkin in Vietnam (Figure 1c).