Substrate Selection of Ascidian Larva: Wettability and Nano-Structures

Abstract

Ascidians are marine sessile chordates that comprise one of the major benthic animal groups in marine ecosystems. They sometimes cause biofouling problems on artificial structures underwater, and non-indigenous, invasive ascidian species can potentially and seriously alter native faunal communities. Ascidian larvae are usually tadpole-shaped, negatively phototactic, and adhere on substrates by secreting a glue from their adhesive organs. Although larvae often prefer hydrophobic surfaces, such as a silicone rubber, for settlement, hydrophobic materials are often used to reduce occurrence of fouling organisms on artificial structures. This inconsistency may indicate that an attractive surface for larvae is not always suitable for settlement. Micro-scale structures or roughness may enhance the settlement of ascidian larvae, but settlement is significantly reduced by a nano-scale nipple array (or moth-eye structure), suggesting functional properties of similar structures found on the body surfaces of various invertebrates. The substrate preferences of larvae should be one of the important bases in considering measures against biofouling, and this review also discusses the potential uses of materials to safely reduce the impacts of invasive species.

Study on the superhydrophobic coatings with antifouling and anticorrosion properties

“…Taken together, the SiO 2 -GSR has excellent long-term antifouling properties, and superhydrophobicity exerts strong antifouling effects through decrease the adhesion strength of microorganisms by providing a smaller adhesion area. [34][35][36] Anticorrosion property of the coating…”

“…This is due to the self-cleaning properties of superhydrophobic coatings, and this property was attributed to the air layer captured by the rough structure. The air layer as a barrier can efficiently reduce the contact area between the liquid and the coating, [34][35][36] which is not conducive to the growth and adhesion of bacteria. Taken together, the SiO 2 -GSR superhydrophobic coating can prevent the attachment of P. pantotrophus and has antifouling capabilities.…”

Potential Disruptive Effects of Copper-Based Antifouling Paints On The Biodiversity of Coastal Macrofouling Communities

“…Rough and smooth substrata often show differences in composition of benthic communities in comparison with smooth substrata like metal or plastic panels. These differences could be due to the selection of the various types of potential biofoulers on the basis of their settlement capability on the different microtopography, wettability and nanostructures of the substrata (Johnson 1994;Commito and Rusignuolo 2000;Hirose and Sensui 2021). Moreover, a primary bacterial film on a metal surface immersed in natural waters could create electrochemical conditions which accelerate metal corrosion (Dexter 1993).…”

Potential of Ascidians as Extractive Species and Their Added Value in Marine Integrated Multitrophic Aquaculture Systems–From Pests to Valuable Blue Bioresources

“…While several ascidian species present a preference to settle on natural substrates (Hirose and Sensui, 2021), others settle on artificial structures, such as ship hulls, floating docks (Zvyagintsev et al, 2007), and aquaculture infrastructures (Hodson et al, 2000;Khalaman, 2001;Bullard et al, 2013;Rosa et al, 2013), process known as biofouling. At times some species even grow on other organisms being farmed, such as on the shells of mollusks (Dijkstra and Nolan, 2017;Casso et al, 2018).…”