icolls - Sustainable Tourism CRC

ECOLOGY, THREATS AND MANAGEMENT OPTIONS FOR SMALL ESTUARIES AND ICOLLS
event was short lived and lagoonal sedimentation resumed soon after deposition. The late Holocene age of the
sand sheet along with the lack of associated beach deposits and evidence of wave scouring suggest that a higher
sea level hypothesis is unlikely. This deposit is probably the result of rapid high-energy oceanic inundation from
the southeast. The study of washover deposits is often complicated by interpretation, as there is a significant grey
area between deposits attributed to tsunami or storm. We conclude that the sand deposit is the product of a shortlived,
large-scale overwash event attributed to a possible late-Holocene tsunami or exceptionally large storm
event.
Title of paper: Sustainable Management of Intermittently Closed and Open Lakes and Lagoons (ICOLLs):
Knowledge Gaps and Threatening Processes
Author: Angela Arthington and Wade Hadwen
Author's email: a.arthington@griffith.edu.au
Abstract: Sustainable management of ICOLLS is currently hampered by our lack of understanding of the key
processes that maintain these complex ecosystems. Whilst data from permanently open estuarine systems is
likely to be somewhat applicable to ICOLLs, the unique and highly variable physical, chemical and biological
characteristics of these systems suggest that the processes that drive ICOLLs may be somewhat different. To
date, very little research has attempted to determine the ecological structure and functioning of ICOLLs and their
responses to natural and anthropogenic perturbations. Fish faunal surveys dominate the otherwise scant
literature, owing to the numerous commercially valuable species that inhabit these coastal waterways. At present,
there is a lack of integrated research investigating the major processes threatening the ecological sustainability of
ICOLLs. We suggest that the major threatening processes are: eutrophication, contamination, fish extraction,
modification of flow and opening and closing regimes, tourism/recreational use, and coastal development. The
status of ICOLLs in relation to increasing coastal development is of concern, particularly with regard to artificial
opening regimes, STP inputs and excessive runoff from industrial, urban and agricultural land uses. These
human influences undoubtedly threaten the long-term sustainability of ICOLLs and the species that inhabit them.
This paper will highlight areas of research required to strengthen our understanding of ICOLL ecosystems, and
the role they play in sustaining biodiversity, ecological function and fisheries production in the coastal zone.
Title of paper: Contributions of jellyfish to nutrient regeneration in coastal lagoons
Author: Kylie Pitt, Klaus Koop & David Rissik
Author's email: K.Pitt@griffith.edu.au
Abstract: Scyphozoan jellyfish abound in coastal lagoons of New South Wales and at times their biomass can
exceed 500 tonnes km-1. The rhizostomes Catostylus mosaicus and Phyllorhiza punctata are the most common
species. Both species contain symbiotic zooxanthellae but concentrations appear to be much greater in P.
punctata. Our experiment measured the rates at which NH3, PO4 and NOX were taken up or excreted by each
species and in two controls: a “water only” control and a “mucus” control. Experiments were repeated twice
during the day and twice at night and were conducted under both ambient and enriched nutrient conditions. P.
punctata excreted small concentrations of NH3 under ambient nutrient conditions (average 37 mg kg-1 WW hr-
1) but under enriched conditions excreted NH3 during the night (49 mg kg-1 WW hr-1) and took up NH3 during
the day (123 mg kg-1 WW hr-1). In contrast, C. mosaicus excreted NH3 at a rate of 1505 mg kg-1 WW hr-1
during the day and 1016 mg kg-1 WW hr-1 during the night. P. punctata neither took up nor excreted PO4 but
C. mosaicus excreted PO4 at a faster rate during the day than night (173 cf 104 mg kg-1 WW hr-1). Both C.
mosaicus and P. punctata excreted NOX and, although the rate of excretion for P. punctata varied between the
two experiments conducted during the day, the rate of excretion was consistently greater than for C. mosaicus
(52 and 80mg kg-1 WW hr-1 cf 26 mg kg-1 WW hr-1). The contribution of P. punctata to nutrient regeneration
appears to be small but during times of population blooms, excretion of NH3 by C. mosaicus may meet up to 8%
of the NH3 required by phytoplankton
Title of paper: Aspects of the Quaternary Geomorphology of the Belongil Swamp, Byron Bay, New South
Wales, Australia.
Author: Mitchell Tulau
Author's email: Mitch.Tulau@dipnr.nsw.gov.au
Abstract: Geomorphic investigations have revealed aspects of the Quaternary geomorphic history of the
Belongil Swamp, a back-barrier swamp at Byron Bay. High resolution elevation data with an elevation accuracy
of +/- 25 mm was acquired at approximately 7500 sites by a 6WD all-terrain vehicle linked to GPS satellites.
After post-processing of the data, high resolution contour plans were drafted using software applying a number
of interpolation techniques and presented on a rectified aerial photo base. Detailed soil and stratigraphic
investigations have also been carried out in the wetland and associated Quaternary deposits. Two cores dating to
8710 +/- 50 years BP and yielding pollen and phytoliths have been recovered from near the West Byron STP.
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