title: Roughness-dependent removal of settled spores of the green alga Ulva (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.
authors.affiliation: Tjärnö Marine Biological Laboratory, Department of Marine Ecology Göteborg University SE-452 96 Strömstad Sweden. lena.granhag@tmbl.gu.se
authors.forename: L M
authors.initials: LM
authors.lastname: Granhag
authors.forename: J A
authors.initials: JA
authors.lastname: Finlay
authors.forename: P R
authors.initials: PR
authors.lastname: Jonsson
authors.forename: J A
authors.initials: JA
authors.lastname: Callow
authors.forename: M E
authors.initials: ME
authors.lastname: Callow
mesh_terms: D000268:Adhesiveness; D018441:Biofilms; D008386:Marine Biology; D019904:Polymethyl Methacrylate; D013170:Spores / Q000302:isolation & purification; D013499:Surface Properties; D044445:Ulva / Q000302:isolation & purification*; D014867:Water
chemical_list: D014867:Water; D019904:Polymethyl Methacrylate