Diversity and Spatial Distribution of Plankton in Connected Waters of Bali Strait, Between Eastern Part of Java and Western Part of Bali Island

Bali Strait waters located between Java and Bali Island contain high productivity, which indicated by the high diversity of phytoplankton and zooplankton. The purpose of the research was to understand the local (α), intra-space (β), and regional or total (Υ) diversity values (that expressed as richness) of plankton taken from surface and thermocline layers. The surface observation was carried out at three locations, two locations, with 5 stations of each, nearshore (Banyuwangi/Jawa Island and Southern part of Bali Island) and one location, with 9 stations, offshore (Bali Strait). The thermocline was observed offshore at all 9 stations as the surface. The diversity of each stations (α) were 11-20 for phytoplankton and 7-12 for zooplankton at the surface, then 9-11 and 7-13, respectively at the thermocline. The total diversity (Υ) of phytoplankton was 27 and 13 of zooplankton. Based on the β values, the plankton of nearshore were also found at offshore locations. Furthermore, some species of plankton at the surface were not found in thermocline layer. As a whole, phytoplankton and zooplankton were well distributed at the surface, but showed as specific distribution at thermocline layer, especially for phytoplankton.