The students received prizes of Amazon vouchers

Erika Nishitani (M.Sc. Geographical Info Systems & Environment Management)

“Having submitted my Master’s dissertation, titled “Investigating Change in the Extent and Dynamics of Mangrove Communities in Moreton Bay, Southeast Queensland, Australia,” in August last year, I was delighted to have won the Centre for Aquatic Environment (CAE) Best Dissertation Award at the MSc level. With a degree background in Geographical Information Systems and Environmental Management, I was driven to use the technical GIS and Remote Sensing skills I had developed throughout the year. Mangroves, often underappreciated yet ecologically integral, stand as one of the world’s largest carbon sequesters and productive ecosystems. They are biodiversity hotspots, natural defenders against extreme weather events, and providers of abundant ecosystem services. Mangrove forests cover ~18% of Australian coastlines, comprised of 47 species. The outlined species distribution coupled with the fact that Australia has the third-largest area of mangroves in the world makes it intrinsically one of the most diverse mangrove ecosystems in the world.

In contrast to traditional ground-based monitoring, my dissertation embraced a desk-based approach to investigate the changes in the extent, distribution, and dynamics of mangrove communities in Moreton Bay between 2007-2022. To achieve this research aim I employed the platform Google Earth Engine (GEE) for the data acquisition of Landsat satellite imagery,

pre-processing (ie. filtering and applying masks), delineation of mangrove and non-mangrove cover using a supervised Random Forest algorithm, and accuracy assessments of the created classification models. To comprehend the potential drivers of mangrove landward transgression in Moreton Bay, my study explored climate variability and the impacts of land use and land cover in the region. The spatial and temporal quantification of a land cover dataset and the classified mangrove cover over the study period was accomplished using the Change Detection Wizard of ArcGIS Pro. Additionally, NDVI data indicative of mangrove health, and precipitation data acquired through GEE provided invaluable insights.

Over the study duration, the findings revealed significant growth of mangrove extents, with the largest areas of growth primarily identified at and around points of discharge from the hydrological systems of highly urbanized catchments. Moreover, rainfall data documented in conjunction with mangrove extent data highlighted the influence of extreme rainfall events in transporting constituents of poor water quality, thus, contributing to mangrove growth. While the primary observations of the significant mangrove growth in Moreton Bay appear favorable, a closer look offers an alternate hypothesis – that mangroves are encroaching landward at the expense of saltmarsh communities. This discovery, in conjunction with the fact Moreton Bay is one of Australia’s largest Ramsar sites listed under the convention, underscores the critical importance of integrated monitoring and management of wetland ecosystems, protecting its rich nature, culture, and history.”

Jess Saunders (B.Sc. Environmental Sciences)

An investigation into how blue mussels’ reproductive physiology is affected when exposed to endocrine disrupting chemicals (EDCs), identified in Chichester Harbour.  Desk-based research states how Chichester Harbour is vulnerable to pollution as a result of direct exposure to wastewater and anthropogenic activities. Past research focuses on microbial activity in the harbour, but after a skewed sex ratio and reduced abundance to native oyster species, EDCs are a priority concern. Invertebrates are a key element within intertidal ecosystems, specifically filter-feeding bivalves which help identify the scope of the environment’s condition, therefore blue mussels (Mytilus Edulis) were utilised for this project. This report is in collaboration with Redpol-Interreg, to provide data to reduce endocrine disrupting chemicals at the source.  A group of mussels were exposed in Chichester’s Harbour for two weeks, with a control group placed in Brighton University laboratories. Methods including histopathology and, molecular analysis of the male target gene VCL and female gene VERL were undertaken through gel electrolysis. Histopathology results presented pre-spawning for male gametogenesis and atresia in female gonads in the mussels exposed to EDCs. Significant pathologies were also identified when exposed to EDCs, including increased lipid storage, mucus production and degradation of tissue. The gene expressions of VCL and VERL were downregulated when exposed to concentrations of EDCs, prohibiting the bivalve’s ability to fertilise gametes in reproductive processes. Pollution in Chichester’s Harbour actively impaired M. Edulis reproductive physiology after only two weeks of exposure. Invertebrate that inhabits endocrine chemically polluted ecosystems are at risk of damage to their reproductive success and species population. The future of ecosystems is progressing in vulnerability, with a discussion of how climate change develops a heightened susceptibility to EDCs. In reference to wider research an increase in temperature correlates with environmental stress and reproductive impairments observed in blue mussels, therefore establishing another factor risking the survival of invertebrates. Conclusions state that Chichester Harbours effluence to endocrine disrupting chemicals has developed impairments to the reproductive physiology of blue mussels, which can be applied to other species of invertebrate. Further research should continue to be conducted within the field of ecotoxicology on invertebrates, for the establishment of biomarkers, a surveying technique to sustain our ecosystems in the future.

These dissertation prizes were offered by the Centre for Aquatic Environments as part of the CORE funding in 2022/2033 and will hopefully be continued by the Centre for Earth Observation Science

We wish Erika and Jess all the very best for their future careers