Marine lakes of karst islands in Ha Long Bay (Vietnam)

Sponge species composition, abundance, and cover in marine lakes and coastal mangroves in Berau, Indonesia

“…Some individual transects did exhibit differences in composition between sampling events, but there was little evidence of a strong and consistent change in composition across sites over a longer time period (> 6 mo) based on the ordinations as indicated in Figs. 3 & 4. Our lack of directional change differs somewhat from results obtained in Vietnamese marine lakes, where degeneration of species and subsequent variation in local assemblages was observed after 6 mo and longer due to heightened temperature and extreme rainfall during the monsoon season (Cerrano et al 2006, Azzini et al 2007. Our contrasting results with Vietnam may be due to the fact that seasonal differences are much less pronounced in Berau than in Vietnam.…”

“…several species of the genus Haliclona). The only representative study of sponge fauna in marine lakes in the Indo-Pacific so far was conducted in Ha Long Bay in Vietnam (Cerrano et al 2006, Azzini et al 2007). The Indonesian and Vietnamese marine lakes share few species, though similar patterns in assemblage structures are seen in both.…”

“…These classes of higher taxonomic groups of associated organisms were selected based on preliminary data that showed that these groups were abundant in marine lakes (Hoeksema 2004, Cerrano et al 2006, Colin 2009, Becking et al 2011 and potentially may affect the species composition, abundance and cover of sponges. Subsequently, sponge species and their abundance (number of individuals per species) were recorded within the 1 m 2 quadrats.…”

“…The total number of marine lakes worldwide is estimated at only ~200 with clusters of 10 or more lakes occurring in areas with a karstic limestone landscape such as Croatia, Bermuda, Vietnam, Palau, and Indonesia (Dawson et al 2009). Preliminary surveys of macrobiota in marine lakes in Indonesia, Vietnam, and Palau have shown that sponges, algae, ascidians, and mollusks are the most dominant taxa in terms of abundance and diversity (Hoeksema 2004, Cerrano et al 2006, Colin 2009, Becking et al 2011). This enclosed environment has set the stage for small, isolated, rapidly evolving populations, and possibly endemic (sub)species (Holthuis 1973, Maciolek 1983, Tomascik & Mah 1994, Fransen & Tomascik 1996, Massin & Tomascik 1996, Dawson & Hamner 2005.…”

“…Marine lakes are anchialine systems -small bodies of landlocked seawater isolated to varying degrees from the surrounding marine environment (Holthuis 1973, Hamner & Hamner 1998, Colin 2009, Becking et al 2011. The marine character of these systems is maintained by subterranean tunnels, fissures, or small dissolution channels in the surrounding rock, connecting the lakes to the adjacent sea, and as such display a wide variety in the degree of connection to the sea and environmental regimes within the lakes (Hamner & Hamner 1998, Cerrano et al 2006, Azzini et al 2007, Becking et al 2011. The total number of marine lakes worldwide is estimated at only ~200 with clusters of 10 or more lakes occurring in areas with a karstic limestone landscape such as Croatia, Bermuda, Vietnam, Palau, and Indonesia (Dawson et al 2009).…”