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Introductory Talk
Ship mediated marine bioinvasion: Need for a comprehensive global action plan
Anil AC*, K Venkat
National Institute of Oceanography, Dona Paula, Goa, India
*Email: acanil@nio.org
Introduction of alien organism into an ecosystem and its successful establishment is referred to as bioinvasion. In its native environment the population of the organism is controlled by ecosystem interactions, however, the absence of such a control mechanism can trigger a population explosion. Hence in an alien environment introduced organisms can turn out to be a threat, bringing about untold, often undesirable consequences in the ecosystem. Bioinvasions can be natural, intentional or unintentional, and at times the impact not easily delineated due to multi-dimensional effects. A review of invertebrate invasions across the world indicates inter-linkages between responsible vectors. In this presentation an effort is made to illustrate the geographical spread of invasive invertebrate organisms from different bioregions and the possible causes for their success. Examining the bioinvasion potential of different organisms needs consideration of reproductive pathways, development and habitat requirements. A synthesis of this information for different taxa indicates that in those cases where larval duration is long and food and environmental requirements are not in a narrow band, the possibility of larval dispersal through ships ballast is a distinct possibility. Survival of organisms inside ballast tanks is dependent on several factors. Conditions in ballast tanks could be inhospitable to some, when compared to those existing in the wild. In the case of organisms attached to the hull of the ship or sea chests, potential inoculation of high numbers of larvae to the environment increases the strength of the fouling vector in the bioinvasion scenario. In view of this while addressing the marine bioinvasion threat through shipping, equal attention to hull fouling and ballast mediations is required
Keywords: Marine bioinvasion, Ballast water management, Biofouling, Shipping, Invertebrate larval ecology
Recruitment of larvae of Lyrodus pedicellatus (Quatrefages) (Teredinidae, Bivalvia, Mollusca) - influence of primary film
Balaji M*, MV Rao
Wood Biodegradation Centre (Marine), Institute of Wood Science and Technology, Visakhapatnam, India
*Email: balaji.iwst@gmail.com
Recognition of wooden substratum is the critical event in the life history of teredinid larvae for easy settlement and growth. All materials including wood introduced in marine environment develop a primary film consisting of organic molecules, bacteria, diatoms, algae, fungi and organic/inorganic detritus. The role of this primary film in aiding larvae to recognize a suitable substratum was well studied in many fouling organisms whereas in the case of wood borers, especially teredinids, this aspect did not receive necessary attention. Therefore, the significance of primary film in facilitating the recruitment of larvae of a teredinid wood borer, Lyrodus pedicellatus (Quatrefages) was studied and the results are presented in this paper.
Keywords: Lyrodus pedicellatus, Biofilms, Bacteria
Industrial Electron Accelerators for Ballast Water Management
Mittal KC ¹*, S Acharya1, M Mathur ²
¹Electron Beam Center, Accelerator and Pulse Power Division, BARC, Mumbai, India
²Molecular Biology Division, BARC, Mumbai, India
Email: *kcm@barc.gov.in
Industrial electron accelerators which produce beams in the energy range of 100 keV to 10 MeV with average power from 1 kW to 500 kW are finding important radiation processing applications in the fields of a) plastic modifications, b) food preservation, c) medical product sterilizations and d) water and air pollution control. The main advantage of electron beam over gamma rays is the availability of very high power, energy and nuclear radiation free processing. Electron accelerators can handle large throughputs as compared to gamma ray sources. High power electron accelerators are being employed for pollution control in the exhaust of thermal power stations (DeSOx/ Denox) as well as for treatment of sludge for safe disposal. It has been found that a dose of 0.2 to 1 kGy is sufficient for treatment of ballast water. Therefore, it is suggested that electron accelerators can be installed at ports for treating ballast water from the ships. BARC had long back realized the enormous potential of these electron beams for non-thermal applications and chalked out an elaborate program to develop these accelerators. Depending on the product and the type of radiation processing, the requirements of energy and power vary vastly. A single accelerator or one type of accelerator cannot meet such diverse requirements. To cover most of the areas of applications, the following three accelerators have been under development at BARC namely: i) 500 keV 10 kW Cock Croft Walton type multiplier DC accelerator (operational), ii) 3 MeV, 30 kW parallel coupled self capacitance type multiplier DC accelerator (under commissioning) and iii) 10 MeV, 10 kW RF Electron Linac (operational). These accelerators have been indigenously developed in India with an objective to demonstrate radiation processing applications in industry. Some of the design features and operational experience of the three accelerators will be discussed in the paper. Experiments to study radiation effects on ballast water can be conducted in collaboration with the interested laboratories.
Keywords: Industrial electron accelerators, Radiation processing applications, High power electron accelerators
Invited Talk
Biofouling research: Lessons learned and potentials for the future
Zahuranec B*
US Office of Naval Research, USA
*Email: bzahuranec@yahoo.com
Starting in the 1950's the US Office of Naval Research, together with many other organizations, supported basic research on the biology and chemistry of marine fouling organisms. As a result of those many years of effort, we now have a much greater appreciation of the complexity of biofouling and the many processes involved when organisms attach to a solid surface in the sea. There are literally hundreds of species involved, ranging from bacteria, fungi and algae to the young forms of macrofoulers such as barnacles and oysters.
Originally, the solution to the biofouling problem, that is, the prevention of biofouling, was by the use of toxic materials, especially toxins incorporating heavy metals such as copper and, more recently, organotins. In other words, killing everything was seen as the desirable approach, until it became clear that due to the persistence of these toxic heavy metals, there are undesirable environmental side effects. This necessitated the banning of the worst offending toxins. Such bans will undoubtedly become more widespread in the future.
Efforts are underway to find truly effective antifouling approaches that are environmentally benign. These include the search for naturally occurring repellents, toxins or other anti-foulants that break down and do not persist in the environment the way heavy metals do. Perhaps the most promising approaches will involve the use of new materials that employ nanotechnology -- approaches that didn't even exist as options until recently. A prime example of this is the AMBIOS project (web site: http://www.ambio.bham.ac.uk/), a 5 year project being supported by the European Commission. A consortium of 31 organizations, it is attempting to use nanotechnology of surfaces to produce non-toxic materials that do not foul in the sea.
Keywords: Biofouling, Toxic heavy metals, Nanotechnology
Inter-specific variation in adhesion strength of barnacles on foul-release coatings
TEO Serena L-M, LIM Chin-Sing, SIN Tsai-Min
Tropical Marine Science Institute, National University of Singapore, Singapore 119223
Email: tmsteolm@nus.edu.sg
As a result of the environment impact of toxic coatings, much effort is being directed to the development of low surface energy silicone and fluoropolymers. Many organisms do attach to these surfaces but the bioadhesive bond is weak and most organisms easily fall off. Thus, the efficacy of these coatings depends on enhancing the fouling release capabilities of these coatings, and better understanding of the adhesion of organisms is needed to further improve the technology. It has been observed that when barnacles attach to siloxane elastomeric coatings, a thick adhesive plaque forms on its base plate. Studies by Holm et al. (2005) have demonstrated that the adhesion strength of barnacle glues within genetic families of barnacles may vary significantly. In this paper, we report the variation in adhesion strength of three different barnacle species to non-stick foul release coatings. Amphibalanus cirratus, A. reticulatus and A. amphitrite occur together at our site, and adhesion measurements were recorded for the three species from the same panels. As barnacles exhibit plasticity in their form under different environmental conditions, we also measured the height and diameter of the barnacles. It was observed that the variation in adhesion strength was also related to the aspect ratio of the barnacles.
Keywords: Barnacle adhesion, Antifouling, Fouling release coatings
Invasion history and habitat of the alien amphipod Gammarus tigrinus Sexton: Modelling of its further range expansion in the northern Baltic Sea
Kristjan Herkül*, Jonne Kotta
Estonian Marine Institute, University of Tartu, Mäealuse 10a, Tallinn 12618, Estonia
*Email: kristjan.herkyl@sea.ee
The northern Baltic Sea is species poor and each ecosystem function is often represented by a single or a few species. Thus, the loss or addition of a species may correspond to the loss or addition of ecosystem function. Over 100 different alien species have been recorded in the Baltic Sea. North-American Gammarus tigrinus Sexton was introduced to Europe in ballast water and was first recorded in England in 1931. In the Baltic Sea G. tigrinus was found already in 1975, but the significant range expansion started in the 1990s. In the northern Baltic Sea G. tigrinus was found for the first time in 2003. The invasion of G. tigrinus was extremely rapid and during two years the species became established and even dominant gammarid in many locations throughout the northern Gulf of Riga, northern Baltic Sea. Following the establishment, G. tigrinus and native gammarid species seldom existed at the same site indicating spatial separation between native and invasive species. The invasive species was more successful in shallow and sheltered soft bottom areas than in deeper and exposed stony areas. The abundance structure of G. tigrinus was mostly related to the biomass of green algae, charophytes and higher plants. The densities of native gammarids were best explained by the biomass of brown and red algae. Concurrent with the invasion of G. tigrinus both the density and diversity of native gammarids have declined indicating competitive superiority of G. tigrinus over native gammarids. GIS-based generalized regression analysis and spatial prediction (GRASP) were used as methods for predicting the further range expansion of the alien amphipod. Model validation showed good accuracy in predicting the occurrence of G. tigrinus indicating that GRASP approach may be helpful for predicting the distribution of invasive species.
Keywords: Alien, Amphipod, Baltic Sea, Gammarus tigrinus, GIS, Modelling
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