Professor Jennifer Verduin

The estimation of the time since death (minimum Post Mortem Interval, minPMI) is an essential aspect to a forensic investigation, and this is particularly complex when a body is found in a marine environment, submerged, floating or beached. The estimation of the minPMI of a body found on land is generally based on the presence of carrion insects (Diptera: Calliphoridae; Sarcophagidae; Muscidae). In the marine environment, beside the minPMI, the time spent by the body underwater (minPMSI, minimum Post Mortem Submersion Interval) or floating (FI, Floating Interval) are necessary for a correct crime scene reconstruction. The presence of barnacles (Crustacea: Cirripedia) is one parameter that has come under recent scrutiny because of their colonisation and permanent settlement on human remains and their accompanying items, such as clothing and shoes. However, research in this field to present day is limited and focused in USA and Europe, and has not considered human clothing materials (fabrics). This research is focused on the colonisation – settlement preference and growth – of barnacles on cotton, velvet, satin and neoprene. Polystyrene floats (PFs), covered by the four types of fabric, were submerged over a period of six months off the coast of Perth, Western Australia. The aims of this research were 1) the identification of marine species colonising the fabrics, with special attention to barnacles; 2) the identification of which fabric provides the most desirable environment for colonisation; and 3) the identification of which factors affect the growth rate of the different species. Three species of barnacles (Balanus trigonus Darwin, Amphibalanus reticulatus (Utinomi) and A. variegatus (Darwin)) were present in varying amounts and sizes. The colonisation process of the barnacles happened rapidly, with colonisation observed in within the first month on neoprene. Statistical analyses were used to determine statically significant relationships between the barnacles’ number, diameter and distribution, compared to the type of fabric. Overall, the favourable substrata for this research were neoprene, followed by satin. Cotton, instead, showed a low colonisation, possibly due to the partial deterioration of the material over time. In contrast, velvet showed an inconsistent colonisation rate. The settlement preference observed was on the bottom half of the floats (away from sunlight exposure) and areas where the fabric creased. This study is the first to provide data to support the estimation of PMSI of clothed bodies that can be found in Western Australian marine waters.

Global seagrass losses parallel significant declines observed in corals and mangroves over the past 50 years. These declines combined have resulted in accelerated losses to ecosystem services in coastal waters globally. Seagrass meadows can be extensive (100s of km2) and long-lived (1000s of years) with the meadows persisting predominantly through vegetative (clonal) growth. They also invest a large amount of energy in sexual reproduction. This paper explores the role that sexual reproduction, pollen and seed dispersal play in maintaining species distributions, genetic diversity and connectivity among seagrass populations. It also addresses the relationship between long distance dispersal, genetic connectivity and the maintenance of genetic diversity that may enhance resilience to stresses associated with seagrass loss. Our re-evaluation of seagrass dispersal and recruitment has altered our perception of the importance of long distance dispersal and has revealed extensive dispersal at scales much larger than previously thought possible.