[Parameters: Topic='BIOLOGICAL CLASSIFICATION', Term='PLANTS', Variable_Level_1='MICROALGAE']
Cascading effects of global climate change on near shore benthic communities in the AntarcticEntry ID: ASAC_2300
Abstract: Metadata record for data from ASAC Project 2300
See the link below for public details on this project.
---- Public Summary from Project----
Antarctic reefs, like their tropical counterparts, harbour a high diversity of animal life. For the first time we will determine how global warming will affect food availability to the animals which comprise the structural components of the reefs. ... Ultimately, we wish to predict the cascading effect through the community as one component changes.
With the confirmation that sponges in Antarctic waters graze on ultraplankton there is now a global overview that sponges are the primary benthic organism that is responsible for linking the pelagic microbial food web to the benthos. Like other shallow water demosponges, sponges in Antarcticia are omnivorous sponges that graze nonselectively, consuming both heterotrophic and phototrophic organisms. Retention efficiencies of ultraplankton are similar to other sponges measured using similar techniques from shallow water to the deep sea, the tropics to boreal waters.
The large amounts of water processed by these benthic suspension feeders and their diet places these sponges squarely within the functional group of organisms that link the pelagic microbial food web to the benthos. The number of macroinvertebrates that have been shown to side- step the microbial loop and directly utilize the base of the microbial food web as a primary food source is ever growing and currently includes demosponges, ascidians, soft corals, and bivalves. Dense macroinvertebrate communities dominated by demosponges and corals in shallow water have been shown to remove as much as 90% of the ultraplankton from the water that passes over them. The daily fluxes of ultraplankton to these communities ranges from 9 to 1970 mg C day-1 m-2. We conservatively estimate that this single species of sponge, which comprises only a portion of the benthos, mediates a flux of 444 mg mg C day-1 m-2 from the water column, which places it in the range of shallow-water temperate and boreal systems.
Furthermore, we found that physical disturbance results in changes in community structure. The subtidal rocky coasts near Casey are similar to many of the exposed rocky coasts of the world that support extensive stands of macroalgae that form a strong positive association with understorey encrusting coralline algae. Loss of canopies of algae on temperate coasts often triggers large and predictable changes to the assemblage of understorey taxa. We observed large negative effects of removing canopies of H. grandifolius on encrusting corallines growing beneath, with such effects consistent with predictions of previous research on tropical and temperate coasts. However, elevating concentrations of nutrients did not greatly reduce the magnitude of the negative effects of canopy removal. Nevertheless, our results suggest that disturbance (removal) to canopies of H. grandifolius has large consequences for those organisms associated with this widely distributed (circumpolar) species of canopy-forming algae.
See the full copy of the final report (available for download from the URL given below) for more information.
Also included in the download file, are five Excel spreadsheets. The spreadsheets contain the data collected from the transects, quadrats, etc (see the final report for more information). Where possible the spreadsheets have been converted to csv files.
The fields in this dataset are:
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Start Date: 2003-09-30Stop Date: 2005-03-31
BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES
BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > SPONGES
BIOLOGICAL CLASSIFICATION > PLANTS > MICROALGAE
BIOLOGICAL CLASSIFICATION > PLANTS > MACROALGAE (SEAWEEDS)
BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON > ZOOPLANKTON
BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON > PHYTOPLANKTON
BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON
BIOSPHERE > AQUATIC ECOSYSTEMS > BENTHIC HABITAT
BIOSPHERE > ECOLOGICAL DYNAMICS > SPECIES/POPULATION INTERACTIONS > SPECIES PREDATION
BIOSPHERE > ECOLOGICAL DYNAMICS > SPECIES/POPULATION INTERACTIONS > GRAZING DYNAMICS/PLANT HERBIVORY
Quality Values provided in temporal and spatial coverage are approximate only.
This record has been updated by staff at the Australian Antarctic Data Centre (rather than the listed investigator), and therefore it's accuracy and quality cannot be guaranteed.
See the final report at the URL below for full and accurate information.
Access Constraints These data and a copy of the final report are available for download from the URL given below.
Use Constraints This data set conforms to the PICCCBY Attribution License
Please follow instructions listed in the citation reference provided at the
URL below when using these data.
Data Set Progress
Distribution Media: HTTP
Distribution Size: 24 kb
Distribution Format: word, csv, excel
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 2 9351 2440
Fax: +61 2 9351 2558
Email: apile at bio.usyd.edu.au
School Of Biological Sciences University of Sydney RM 202A HAYDON-LAURENCE BLDG A08
Province or State: New South Wales
Postal Code: 2006
Irving, A. D., S. D. Connell, E. L. Johnston, A. J. Pile, B. M. Gillanders. (2005), The response of encrusting coralline algae to canopy loss: an independent test of predictions on an Antarctic coast., Marine Biology, 144, 361-368
Pile, AJ, EL Johnston, SD Connell and BM Gillanders. (December 2005), Benthic-pelagic coupling of the microbial food web by Antarctic sponges, Targeted for Marine Ecology Progress Series
Johnston EL, SD Connell, AD Irving, AJ Pile and BM Gillanders (December 2005), Characterising shallow rocky-reef assemblages from the Windmill Islands coast, East Antarctica, Targeted for Polar Biology
Connell, SD, EL Johnston, AD Irving, TE Wernberg, BM Gillanders, BD Russell, AJ Pile (May 2006), How do the understorey assemblages at the Windmill Islands of Antarctica compare to those in Australia?, Targeted for Polar Biology
Creation and Review Dates
DIF Creation Date: 2003-05-26
Last DIF Revision Date: 2011-07-29