Mangrove-sponge associations: a possible role for tannins

Abstract

A positive correlation between sponge coverage and tannin concentrations in prop roots of Rhizophora mangle L. has previously been reported. However, the ecological role of tannins within the mangrove sponge association remains speculative. This study investigated whether tannins play a role in sponge recruitment and assessed tannin and polyphenol production in R. mangle roots in response to sponge colonization. We demonstrated in a field experiment using artificial substrates with different tannin concentrations that tannins are positively involved in larval recruitment of the sponge Tedania ignis and that roots significantly enhanced tannin and polyphenolic content in response to natural and experimental sponge fouling. Differential recruitment in response to tannins may have been the result of a behavioral response in sponge larvae. It is also possible that tannins affected the structure of the fouling microbial biofilm on the artificial substrate, or tannins affected the post-settlement dynamics of sponge recruits. Elevations in concentrations of tannins and polyphenolic compounds upon coverage with sponges, combined with differential recruitment of T. ignis in response to differences in tannin concentrations, may indicate a positive feedback in recruitment. This may in part explain the typical heterogeneity in sponge coverage and community composition among roots.

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

“…In Haji Buang lake, there were only 2 transects in the mangrove roots (due to limited mangrove cover in this lake), yet these assemblages contained species that were not present in the remainder of the lake. Differential response of sponge larvae to concentration of tannins in mangrove roots may play a role in structuring the assemblages associated with mangroves (Hunting et al 2008(Hunting et al , 2010. The ability to resist tidal exposure may, furthermore, be a strong selective trait for species survival in mangrove systems.…”

Mangrove and coral reef sponge faunas: untold stories about shallow water Porifera in the Caribbean

“…Reef faunas are believed to be mostly controlled by biotic factors, mainly fish predation and space competition with the development of allelopathic defense mechanisms (Dunlap & Pawlik, 1996Pawlik, 1997Pawlik, , 1998Wulff, 1997Wulff, , 2005Engel & Pawlik, 2005b). Recent studies suggest that biological features such as growth rates, recruitment patterns, asexual reproduction, and root-sponge interactions may vary between sponge species, and determine the presence, abundance, and dynamics of sponge populations on mangrove roots (Farnsworth & Ellison, 1996;Díaz & Rützler, 2009;Hunting et al, 2010). However, this analysis of mangrove and coral reef sponge faunas lacks comprehensive systematic comparison.…”

Root-derived organic matter confines sponge community composition in mangrove ecosystems

“…Both species were chosen for their fast growth (Wulff 2005(Wulff , 2010. For detailed maps of the study sites, see Hunting et al (2008, 2010a) and De Goeij et al (2008b.…”

“…The effect of mangrove DOM on sponges was assessed with artificial substrates made from agar that allows mangrove root extracts to slowly diffuse into the overlying water (e.g., Henrikson and Pawlik 1995;Browne and Zimmer 2001;Hunting et al, 2010a). Each mimicry gel was prepared in plastic containers (volume 100 cm 3 ) and consisted of 3% agar (Molecular Genetics/Granulated, Roth, Germany) and 1 mL of mangrove root extract, added to the agar suspension at~50°C.…”