Diatom community structure on in-service cruise ship hulls

Abstract

Diatoms are an important component of marine biofilms found on ship hulls. However, there are only a few published studies that describe the presence and abundance of diatoms on ships, and none that relate to modern ship hull coatings. This study investigated the diatom community structure on two in-service cruise ships with the same cruise cycles, one coated with an antifouling (AF) system (copper self-polishing copolymer) and the other coated with a silicone fouling-release (FR) system. Biofilm samples were collected during dry docking from representative areas of the ship and these provided information on the horizontal and vertical zonation of the hull, and intact and damaged coating and niche areas. Diatoms from the genera Achnanthes, Amphora and Navicula were the most common, regardless of horizontal ship zonation and coating type. Other genera were abundant, but their presence was more dependent on the ship zonation and coating type. Samples collected from damaged areas of the hull coating had a similar community composition to undamaged areas, but with higher diatom abundance. Diatom fouling on the niche areas differed from that of the surrounding ship hull and paralleled previous studies that investigated differences in diatom community structure on static and dynamically exposed coatings; niche areas were similar to static immersion and the hull to dynamic immersion. Additionally, diatom richness was greater on the ship with the FR coating, including the identification of several new genera to the biofouling literature, viz. Lampriscus and Thalassiophysa. These results are the first to describe diatom community composition on in-service ship hulls coated with a FR system. This class of coatings appears to have a larger diatom community compared to copper-based AF systems, with new diatom genera that have the ability to stick to ship hulls and withstand hydrodynamic forces, thus creating the potential for new problematic species in the biofilm.

Grooming using rotating brushes as a proactive method to control ship hull fouling

“…This frequency of hull cleaning is insufficient to reduce the risk of invasive species and may leave settlement cues from macrofouling organisms that influence subsequent settlement (Ralston & Swain 2014). It has also been shown that the nature and quantity of biofilms present differs among the types of antifouling (AF) coatings (Zargiel et al 2011;Hunsucker et al 2014;Muthukrishnan et al 2014;Zargiel & Swain 2014). Specifically, the age, composition, and thickness of a biofilm have been shown to influence the organisms that subsequently settle on a coated surface as well as their adhesion and growth properties (Dobretsov et al 2013;Mieszkin et al 2013;Shikuma et al 2014).…”

Long alkyl-chain imidazolium ionic liquids: Antibiofilm activity against phototrophic biofilms

“…Biofilm growth dominated by diatoms has been reported on ship hulls coated with foul release coatings [9]. Some natural bioactive compounds have also been reported for their anti-algal biofilm potential [10,12].…”

“…Microalgae are significant contributors of biofilm growth in case of marine environments [8]. The biofilms formed on ship hulls are often dominated by diatoms [9]. The metabolic activities of photosynthetic microalgae can promote corrosion of stainless steel via release of oxygen and hydrogen peroxide [5].…”

“…Navicula sp. was chosen for the study because i) it is a common fouling diatom frequently encountered in power plant cooling water systems [11] and comprises a major proportion of the microalgal biofilm on surfaces exposed to the sea, [1,12,20] ii) it is a dominant player in microalgal biofilms formed on anti-fouling and foul release coatings [8], and iii) it is an important constituent of the microalgal biofilms on in-service ship hulls [9]. It is a relatively fast growing diatom, wherein the growth plateau is obtained within 6 days.…”

“…Fouling diatoms such as Amphora, Cocconeis, Navicula and Nitzschia sp. are commonly encountered in biofilms [7,9,11,12]. Consequently, most of the laboratory scale studies on algal biofilms have used the above mentioned organisms as model systems [2,13,14].…”