Roughness-dependent Removal of Settled Spores of the Green AlgaUlva(syn.Enteromorpha)Exposed to Hydrodynamic Forces from a Water Jet

Abstract

Topographic features change the hydrodynamic regime over surfaces subjected to flow. Hydrodynamic microenvironments around topographic structures may have consequences for recruitment and removal of propagules of marine benthic organisms. The settlement and adhesion of zoospores from the green alga Ulva linza (syn. Enteromorpha linza) to defined topographies was investigated. A range of topographic size scales (Rz: 25-100 microm) was manufactured from plankton nets, creating patterns with ridges and depressions. The topographic scales span a roughness similar to that of natural substrata and antifouling coatings. Spores were removed from the surfaces by a calibrated water jet. Fewer spores were removed from the smallest topographic structure tested (Rz: 25 microm) compared to both the smooth (Rz: 1) and the roughest (Rz: 100 microm) structures. Zoospores that settled in depressions were less likely to be removed compared to spores on the ridges. The results in terms of the interaction between surface topography and hydrodynamic forces have implications for both natural substrata exposed to wave action and antifouling surfaces on ships' hulls. The possible effects of topography on increasing zoospore adhesion and offering a refuge from hydrodynamic forces are discussed.

The influence of surface lubricity on the adhesion of Navicula perminuta and Ulva linza to alkanethiol self-assembled monolayers

“…Microtopography and surface roughness influence both the settlement and attachment strength (Granhag et al 2004) of U. linza spores. Similarly, surface energy and wettability have been shown to influence the settlement behaviour of Ulva zoospores , the attachment of marine bacteria Cobetia marina (Ista et al 2004) and the attachment strength of U. linza and the diatom Amphora spp.…”

Rafting on abiotic substrata: properties of floating items and their influence on community succession

“…longevity) among abiotic floating substrata, they also differ in some characteristics that are relevant in the context of species colonization and rafting. Surface rugosity, known to affect settlement and survival of sessile organisms (Dudley & D'Antonio 1991, Wahl & Hoppe 2002, Faimali et al 2004, Granhag et al 2004, may differ substantially among substrata. Moderate rugosity facilitates colonization because propagules find better substratum adhesion in surface depressions (Granhag et al 2004) or protection against grazers (Wahl & Hoppe 2002, Hutchinson et al 2006.…”

“…Connell & Slatyer 1977, Platt & Connell 2003, Underwood & Chapman 2006. A number of studies have also explored the importance of substratum rugosity, which can influence initial settlement and survival of colonists (Wahl & Hoppe 2002, Faimali et al 2004, Granhag et al 2004, Hutchinson et al 2006. However, rugosity effects mainly appear during very initial stages but lose relevance during later stages of community succession (e.g.…”

Methods of assessing antifouling and foul-release efficacy of non-toxic marine coatings

“…Several laboratorybased systems have been further developed for removing algal spores and young plants of U. linza, 37,45,46 the diatom Navicula perminuta 37 and barnacle cypris larvae of A. amphitrite. 38 Cassé et al 37 developed as part of a high-throughput method a water-jet system using a 24-well plate format for removal of algal spores (U. linza) and a diatom (N. perminuta) and a method using coated microscope slides to assess adhesion of young plants of Ulva (also known as sporelings).…”