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When synthetic materials are submerged in marine environments, dissolved matter and marine organisms attach to their surfaces by a process known as marine fouling. This phenomenon may lead to diminished material performance with detrimental consequences. Bioinspired surface patterning and chemical surface modifications present promising approaches to the design of novel functional surfaces that can prevent biofouling phenomena. In this study, we report the synergistic effects of surface patterns, inspired by the marine decapod crab Myomenippe hardwickii in combination with chemical surface modifications toward suppressing marine fouling. M. hardwickii is known to maintain a relatively clean carapace although the species occurs in biofouling communities of tropical shallow subtidal coastal waters. Following the surface analysis of selected specimens, we designed hierarchical surface microtopographies that replicate the critical features observed on the crustacean surface. The micropatterned surfaces were modified with zwitterionic polymer brushes or with layer-by-layer deposited polyelectrolyte multilayers to enhance their antifouling and/or fouling-release potential. Chemically modified and unmodified micropatterned surfaces were subjected to extensive fouling tests, including laboratory assays against barnacle settlement and algae adhesion, and field static immersion tests. The results show a statistically significant reduction in settlement on the micropatterned surfaces as well as a synergistic effect when the microtopographies are combined with grafted polymer chains.

Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted with amphiphilic perfluoroalkyl polyethylene glycol (fPEG) side chains, was synthesized and subsequently used to introduce amphiphilic character to the LbL film. The structure of the polyanion was confirmed by FTIR and NMR. Amphiphilicity of the film assembly was demonstrated by both water and hexadecane static contact angles. XPS studies of the cross-linked and annealed amphiphilic LbL films revealed the increased concentration of fPEG content at the film interface. In antifouling assays, the amphiphilic LbL films effectively prevented the adhesion of the marine bacterium Pseudomonas (NCIMB 2021).

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Molecular design, fabrication, and properties of thinfilm coatings based on poly(2-methyl-2-oxazoline) (PMOX) and its copolymers were investigated to tackle problem of marine and bacterial fouling prevention. The ultraviolet crosslinkable macromonomer poly(2-methyl-2-oxazoline) dimethylacrylate was synthesized by cationic ring-opening polymerization in a microwave reactor initiated by 1,4-dibromobutane. In order to study the charge effect of the PMOX coatings on the adhesion of fouling organisms, PMOX surfaces with negative, neutral, and positive f-potential values were prepared by copolymerization with the positively charged monomer [2-(methacryloyloxy)-ethyl]trimethylammonium chloride. The coatings were stable in sea water for at least 1 month without significant reduction in the film thickness. The marine antifouling activity was evaluated against barnacle cyprids Amphibalanus amphitrite and algae Amphora coffeaeformis. Results showed that PMOX coatings provide effective reduction of the settlement regardless of the molar mass and surface charge of the polymer. Bacterial adhesion test showed that PMOX coatings effectively reduce Staphylococcus aureus and Escherichia coli adhesion. Owing to its good stability and antifouling activity PMOX has a great potential as antifouling coating for marine antifouling applications. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 275-283

The genus Agelas comprises a group of tropical and subtropical reef sponges that contains large, long-lived, often brightly colored and conspicuous species, distributed throughout the tropica l western Atlantic, temperate northern Atlantic (Mediterranean Sea), and western and central Indo-Pacific Realms. Among tropical sponge genera, Agelas is one with similar species richness in the Greater Caribbean in comparison to the Indo Pacific. The presence of verticillated acanthostyle spicules and a fibroreticulate skeleton of spongin fibres cored and/or echinated by spicules characterize this group. Taxonomic identification relies on a combination of characters, where external morphology and color play a key role, owing to the paucity of microscopical characters. Thus, there is still a great deal of taxonomic confusion, even for the more common species. We carried out a detailed revision of Agelas species throughout the Greater Caribbean area using classic taxonomic tools. Samples and observations covered Colombia, Belize, Jamaica, the Bahamas, Barbados, Curaçao and Venezuela, and included type material from major museum collections. According to our results, the genus Agelas in the Caribbean has at least thirteen valid species, viz. Agelas sceptrum (Lamarck, 1815); A. dispar Duchassaing& Michelotti, 1864;  A. dilatata Duchassaing & Michelotti, 1864; A. clathrodes (Schmidt, 1870);  A. cervicornis (Schmidt, 1870); A. conifera (Schmidt, 1870); A. schmidti Wilson, 1902;   A. tubulata Lehnert & van Soest, 1996; A. wiedenmayeri Alcolado, 1984;  A. citrina Gotera & Alcolado, 1987; A. sventres Lehnert & van Soest, 1996; A. repens Lehnert & van Soest, 1998; and A. cerebrum Assmann et al., 2001. We found that variation of microscopic characteristics like skeleton arrangement, number of verticills and their spines, and spicule length and width, can be used as taxonomic tools, but only in a thorough comparison with other species in the same sub-regional context. Thus, a certain degree of familiarity with the genus' regional variation is often required. The richness and distribution of these species in the Caribbean area show north/south differences and other ecological patterns are evident.

The Caribbean encrusting and excavating sponges Cliona aprica, C. caribbaea, C. delitrix and C. tenuis (Porifera, Hadromerida, Clionaidae), aggresively undermine and displace live coral tissue. At San Andrés island and Islas del Rosario (Colombian Caribbean), in all 145 observed cases of direct contact of the sponges C. aprica, C. caribbaea and C. tenuis with 17 coral species, corals showed unhealthy signs in their tissue. It was also noticed that the surface of these sponges is colonized by few organisms and that they are rarely preyed upon. To establish the possible use of chemical substances by these sponges in competition for space with corals (allelopathy), as inhibitors of larval settlement (antifouling), and as feeding deterrents against generalist fish (antipredatory), the activity of crude organic extracts was experimentally evaluated. Extracts were prepared in methanol and 1:2 metanol:dichloromethane and incorporated in experimental media at the natural concentration within the sponges. Using an unpublished method being developed by J. Pawlik (University of North Caroline at Wilmington) and M. Ilan (Tel Aviv University), PhytagelTM disks with crude extracts of each of the four sponge species, placed on the coral Montastrea cavernosa, produced a greater degree of polyp mortality than control gels without extract. Gels with extracts of the sponges C. aprica and C. caribbaea + C. tenuis, served in Petri dishes and used as substratum in the field, inhibited significantly the settlement of fouling organisms, in comparison to control gels. In laboratory trials, wheat flour pellets with extracts C. delitrix and C. caribbaea + C. tenuis were significantly rejected by the omnivore reef damselfish, Stegastes partitus, whereas pellets with extract of C. aprica did not deter feeding. These results suggest that substances present in the crude organic extracts of these sponges may be responsible in part for their ability to compete for reef substrata and to defend themselves from potential aggressors.