Attachment of Balanus amphitrite larvae to biofilms originating from contrasting environments

Abstract

This study examined the attachment response of Balanus amphitrite larvae to bacteriadominated biofilms originating from 4 sites of varying environmental conditions in the intertidal region of subtropical Hong Kong waters and during 2 seasons (winter and summer), under both laboratory and field conditions. Using multiple fingerprinting techniques (terminal restriction fragment length polymorphism, denaturing gradient gel electrophoresis and fluorescence in situ hybridization), we observed differences in the bacterial community composition of biofilms originating from the 4 sites. These biofilm samples were used to study the linkage between spatial changes in bacterial communities of biofilms and larval choice at the time of attachment. It was hypothesized that cyprids can distinguish biofilms originating from habitats that support higher recruitment. Both laboratory and field multiple-choice bioassays demonstrated that cyprids preferred to attach on biofilms originating from habitats where recruitment, juvenile growth and survival were the highest, thereby accepting the hypothesis proposed. This study did not identify particular bacterial species or groups in biofilms that attract or inhibit larval attachment, but we could correlate site-specific variations in bacterial community composition with larval choice, whereas bacterial abundance in biofilms was less important in this regard. Overall, this study highlights the significance of site-specific variation in biofilms on larval recruitment and demonstrated the discriminative behavior of barnacle larvae to biofilms originating from contrasting environments in the intertidal region. Thus, attachment cues from biofilms may also play a significant role in generating spatial variation in larval recruitment. KEY WORDS: Balanus amphitrite · Biofilms · Larval attachment · Bacterial community · Barnacle recruitment Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 333: [229][230][231][232][233][234][235][236][237][238][239][240][241][242] 2007 phosis (reviewed by Rittschof et al. 1998). Biofilms exist on virtually all hard substrata, and are agglomerates of macromolecules, bacteria, diatoms, protozoans and fungi (Decho 2000). They also serve as an important cue for larval attachment (reviewed by Holmström & Kjelleberg 1994, Wieczorek & Todd 1998, Maki et al. 2000, Hadfield & Paul 2001, Steinberg et al. 2001. Among different biofilm components, bacteria are primarily responsible for larval attachment, particularly for barnacles (e.g. Maki et al. 1990, Wieczorek et al. 1995. Thus, numerous studies have examined the interaction between the bacterial component of the biofilm and larval attachment (see Qian et al. 2003 and references therein). These studies revealed that barnacle larval response (i.e. attachment induction or inhibition) is primarily determined by the abundance and community composition of bacteria in biofilms. For example, barnacle larvae can distinguish between biofilms of varying composition and pr...

Influences of biofilm-associated ciliates on the settlement of marine invertebrate larvae

“…This phenomenon might explain some of the variations of recruitment onto settlement panels in the field in previous studies that neglected to examine protozoa in the biofilms. For example, settlement of various invertebrates has been found to differ among natural biofilms of different ages (Keough & Raimondi 1995, Bao et al 2007), grown in different seasons (Wieczorek et al 1996, Bao et al 2007, and grown in different locations (Dobretsov & Qian 2006, Hung et al 2007. In these studies and others, such effects have been attributed to assumed differences in the general microbial film community or specifically to measured differences in bacteria, but the ciliate assemblages might also have played important roles.…”

“…More recently, settlement has been shown to relate to the presence of certain taxa of microorganisms, by either corre lation or experimental demonstration. These taxa include bacteria (Dobretsov & Qian 2006, Bao et al 2007, Hung et al 2007, diatoms (Harder et al 2002a, Lam et al 2003, and thraustochytrids (Raghukumar et al 2000). Some metabolites and extracellular polymers of bacteria and diatoms have been isolated and identified as the cues to which various invertebrate larvae respond (Harder et al 2002b, Lau et al 2003, Lam et al 2005, Patil & Anil 2005, Hung et al 2009).…”

Recruitment of the sea urchin Heliocidaris erythrogramma and the distribution and abundance of inducing bacteria in the field

“…Patterns of larval settlement in the field have not yet been related to the more detailed taxonomy of bacteria that induce settlement in the laboratory or the composition of biofilms that exist on recruitment surfaces in the field. A recent and compelling study correlated site-specific variations in bacterial community composition with larval choice of barnacles (Hung et al 2007); however, this study did not identify particular bacterial species or groups in biofilms that attract or inhibit larval attachment. At present, there remains a challenge to demonstrate that the distribution of recruits in the field is actually linked with the distribution of bacteria that are able to induce metamorphosis in the laboratory.…”

Characterization of cues from natural multi-species biofilms that induce larval attachment of the polychaete Hydroides elegans

“…Recruitment success is dependent on the attachment of larvae to the favorable habitat (reviewed by Pawlik 1992). The location of attachment is influenced by various physical cues, such as surface roughness (Barnes 1956), color (Saucedo et al 2005), and surface wettability (Dahlström et al 2004), and biological cues such as the presence of conspecific adults (Jeffery 2002), prey (Hadfield & Scheuer 1985), host organisms (Williamson et al 2000), and biofilms (Qian et al 2003, Hung et al 2007). …”