Brief description
This study examined the impacts of 2 of the most common epibenthic suspension feeders, Sabella spallanzanii and Styela clava, in Port Phillip Bay, by transplanting individuals from the surrounding habitat into 2 x 2m experimental plots. Densities in the plots represented naturally occurring densities, ranging from 0.5 to 10 individuals per m-2 for Sabella and from 0.5 to 5 individuals per m-2 for Styela. At the completion of the 10 week experimental period the numbers of alive and dead Sabella and Styela in each plot were counted. The infauna in each plot was sampled by inserting 2 metal cylinders to a depth of 15cm into each plot. The sediment within each cylinder was vacuumed to a depth of 10cm into a 1mm mesh bag using a diver-operated, water-driven suction device. The total area in each plot that was sampled was 0.2m2 (cylinder diameter = 35.5cm). Macrofauna were counted and identified in the laboratory to the lowest possible taxon, which was mostly Family. There were significant effects on individual taxa at Sabella and Styela densities greater than 1-2 individuals per m-2, which are densities greater than those typically recorded in Port Phillip Bay. There was a significant negative relationship between Sabella density and the abundance of lumbrinerid polychaetes and gammarid amphipods, and between Styela density and the abundance of lumbrinerids, tanaids, crustaceans as a group, and the bivalve Laternula rostrata.Lineage
Maintenance and Update Frequency: notPlanned
Statement: The experiment was set-up by SCUBA divers who marked out forty 2 x 2m plots, 5m apart, in a grid pattern on the sea floor using pegs and string. In each plot, Sabella and Styela were placed haphazardly at densities of 0.5, 2, 5 or 10 Sabella per m-2 and 0.5, 2 or 5m-2 Styela per m-2. There were five replicates of each density plus five replicate control plots. The Sabella and Styela in the plots were collected about 200m from the experimental site and placed in a seawater-filled well on the boat for no longer than 1 hour while all fauna were cleared off the tubes. Sabella were transplanted into the plots by inserting each individual into the sediment using tweezers so that the U-shaped bend at the base of the tube was 100 to 150 mm below the sediment surface. Styela were attached to wooden sticks (200mm long, 2mm diameter) using a cable tie at the base of the stalk. The stick was inserted into the sediment so individuals were upright with the base of the stalk flush with the sediment.
At the completion of the experiment, dead and alive Sabella and Styela in each plot were counted and sediment encompassed within two metal cylinders (35.5cm in diameter x 20cm long) was vacuumed using a diver-operated, water-driven suction device to a depth of 10cm. Macrofauna that remained in a 1mm mesh bag were stained with 0.1% rose bengal and frozen prior to sorting. In the laboratory, the macrofauna sample was split into two 2.8mm and 1mm size fractions. The entire 2.8mm fraction was sorted. The 1mm size faction was split in quarters using a 'Jones-type' sediment splitter, and only two of these subsamples were sorted. Infauna and epifauna in the samples were counted and identified to the lowest possible taxon using a dissecting microscope.
At the completion of the experiment, dead and alive Sabella and Styela in each plot were counted and sediment encompassed within two metal cylinders (35.5cm in diameter x 20cm long) was vacuumed using a diver-operated, water-driven suction device to a depth of 10cm. Macrofauna that remained in a 1mm mesh bag were stained with 0.1% rose bengal and frozen prior to sorting. In the laboratory, the macrofauna sample was split into two 2.8mm and 1mm size fractions. The entire 2.8mm fraction was sorted. The 1mm size faction was split in quarters using a 'Jones-type' sediment splitter, and only two of these subsamples were sorted. Infauna and epifauna in the samples were counted and identified to the lowest possible taxon using a dissecting microscope.
Notes
CreditAustralian Research Council Linkage grant to Mick Keough, Andy Longmore and Jo Klemke
Credit
D. Marshall, S. Hart, M. Reardon, R. Watson, R. Bathgate, J. Ahern, E. Bone and A. O'Brien
D. Marshall, S. Hart, M. Reardon, R. Watson, R. Bathgate, J. Ahern, E. Bone and A. O'Brien
Purpose
The purpose of this study was to experimentally examine the impacts of 2 introduced species on soft sediment assemblages in Port Phillip Bay.
The purpose of this study was to experimentally examine the impacts of 2 introduced species on soft sediment assemblages in Port Phillip Bay.
Issued: 18 06 2007
Data time period: 2001-08 to 2001-11
text: westlimit=114.533; southlimit=-38.117; eastlimit=114.533; northlimit=-38.117
text: uplimit=11; downlimit=11
Subjects
22 083031 |
35 033100 |
BIOSPHERE |
Biosphere | Aquatic Habitat | Benthic Habitat | soft sediments |
Biosphere | Zoology | Invertebrates | epibenthic |
Biosphere | Zoology | Invertebrates | suspension feeders |
COMMUNITY DYNAMICS |
Community Structure |
EARTH SCIENCE |
ECOLOGICAL DYNAMICS |
Human Dimensions | Environmental Impacts | introduced species |
Oceans | Marine Biology | Marine Invertebrates |
Sabella spallanzanii |
Styela clava |
biota |
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Identifiers
- global : f277bc10-7557-11dc-8163-00188b4c0af8