Colonization Patterns at the Substratum‐water Interface: How does Surface Microtopography Influence Recruitment Patterns of Sessile Organisms?

The “rugophilic”; behaviour (e.g. the preference for settling in concavities) of barnacles is well documented. In contrast, little is known about settlement preferences of other species with regard to surface microtopography. In a randomized block design, five different rugosities (smooth, 0.1 mm, 0.5 mm, 1 mm, 5 mm) were exposed to natural fouling in the Baltic Sea. In four experiments, test panels were colonized by Mytilus edulis, Polydora dliata, Balanus improvisus, diatoms, hydrozoa, bryozoa, and several ciliates. Settlement densities and microtopographical preferences for pits or elevations as a function of grain size were evaluated. Rugosities influenced settlement densities and the microtopographical preferences of almost all investigated species. Settlement densities were generally lowest on smooth panels, with most species showing distinct preferences for different rugosities. While a preference for pits was frequent, in some species the proportion of individuals settling on elevations significantly increased with roughness. These data on microtopographical preferences of different species give new insights into interactions between settlement behaviour, surface roughness, boundary layer hydrodynamics and community structure.

Key words:

• microtopography
• fouling
• Balanus improvisus
• Mytilus edulis
• Polydora sp.
• diatoms
• ciliates

Notes

Corresponding author; fax: ++49(0)30–314 21675; e‐mail: Jacob.Koehler@Tu‐Berlin.de