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Lynchpin Scholars

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lewa

2011 - LEWA PERTL: B.Sc. (Hons) scholarship

THESIS: underway

RESEARCH BACKGROUND: The giant kelp (Macrocystis pyrifera) forms an important and distinct community type by creating a habitat of outstanding ecological and economic significance. Over the past few decades, there has been a dramatic decline of M. pyrifera on the east coast of Tasmania due to changes in temperature and/or nutrients from the increased influence of the East Australian Current (EAC) in the region (~ 350km further south). Warm and nutrient poor waters in eastern Tasmania have caused an overall decline of ~90% in M. pyrifera beds forming dense surface canopies between 1946 to 2007. The most considerable decline has occurred at Freycinet Peninsula (95%) and around Bruny Island (98%).

This extensive decline of M. pyrifera in Tasmania waters has triggered a recent Environment Protection and Biodiversity Conservation Act 1999 (EPBC) nomination as a threatened ecological community, which is currently being considered by the Commonwealth. This project provides results needed immediately by the government for conservation management of M. pyrifera.

The study will also investigate the use of the Red Edge Position (REP) index derived from RapidEye imagery to extract a signal indicating M. pyrifera. Current terrestrial applications of REP include crop monitoring and yield prediction, ecosystem disturbance detection, photosynthesis modelling, and canopy stress caused by climate and other factors.  The application of REP to the marine environment is a novel and significant aspect of this study.

The practical methodology to be developed in this project has the potential to inform broader conservation strategies in relation to applying the techniques to other marine algal species for high resolution and accurate monitoring. Climate change is altering ecosystems at an unprecedented rate, therefore high quality data possessing and a high degree of temporal and spatial coverage is needed to efficiently guide planned marine adaptation responses. Remote sensing based on satellite imagery may prove to be effective in such a capacity.

REFERENCES:

Johnson, CR, Banks, SC, Barrett, NS, Cazassus, F, Dunstan, PK, Edgar, GJ, Frusher, SD, Gardner, C, Haddon, M, Helidoniotis, F, Hill, KL, Holbrook, NJ, Hosie, GW, Last, PR, Ling, SD, Melbourne-Thomas, J, Miller, K, Pecl, GT, Richardson, AJ, Ridgway, KR, Rintoul, SR, Ritz, DA, Ross, DJ, Sanderson, JC, Shepherd, SA, Slotwinski, A, Swadling, KM & Taw, N. (2011). 'Climate change cascades: Shifts in oceanography, species' ranges and subtidal marine community dynamics in eastern Tasmania', Journal of Experimental Marine Biology and Ecology.

Ridgway, K. (2007). 'Long-term trend and decadal variability of the southward penetration of the East Australian Current', Geophysical Research Letters, vol. 34, no. 13, p. L13613.

 

suellen phytoplankton

2009 - SUELLEN COOK: Ph.D. thesis write-up support

THESIS: "Ecophysiological, morphological and genetic differences between two Southern Ocean morphotypes of the coccolithophorid Emiliania huxleyi."

RESEARCH SUMMARY:The research characterised the degree of genetic differentiation, pigment content and light handling capacities using microsatellites, HPLC and PAM fluorometry.  The differences revealed between morphotypes reflect an adaptive divergence of the Antarctic Circumpolar Current constrained morphotype B/C warranting recognition of its unique contribution to global carbon cycling.

The results presented in this research have major ramifications for field monitoring using pigment analysis to construct phytoplankton community composition data. This research, building on Medlin et al.’s (1996) proposal to formally elevate three E. huxleyi morpho-types to variety status, namely, var. huxleyi (type A), var. pujosae (type B), and var. kleijniae (type C), added a formal description of the morphologically, ecophysiologically, and genetically distinct Southern Ocean morphotype B ⁄ C (sensu Young et al. 2003), to be raised to variety status as var. aurorae: formally: Emiliania huxleyi var. aurorae S. S. Cook et Hallegr. var. nov.

FINDINGS PUBLISHED IN:  

  • J. Phycol. 47, 615–626 (2011) Ó 2011 Phycological Society of America DOI: 10.1111/j.1529-8817.2011.00992.x

 

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