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Cascading effects of global climate change on near shore benthic communities in the Antarctic

Entry ID: ASAC_2300

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Summary

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:

Location
depth
Species
Transect
Quadrat
Irradiance
PAR

Related URL

Link: GET DATA

Description: Download point for the data - final report and data

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

N: -65.0

S: -68.0

E: 110.0

W: 62.0

Temporal Coverage

Start Date: 2003-09-30

Stop Date: 2005-03-31

Location Keywords

CONTINENT > ANTARCTICA

GEOGRAPHIC REGION > POLAR

Science Keywords

BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES

BIOLOGICAL CLASSIFICATION > ANIMALS/INVERTEBRATES > SPONGES

ISO Topic Category

BIOTA

OCEANS

Platform

FIELD SURVEYS

FIELD INVESTIGATION

Instrument

THERMISTORS

FLOW CYTOMETRY

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
(http://creativecommons.org/licenses/by/3.0/).

Please follow instructions listed in the citation reference provided at the
URL below when using these data.

Ancillary Keywords

ANTARCTICA

BENTHIC COMMUNITIES

Data Set Progress

COMPLETE

Data Center

Australian Antarctic Data Centre, Australia

Data Center URL: http://data.aad.gov.au

Data Center Personnel
Name: DATA OFFICER AADC Phone: +61 3 6232 3244 Fax: +61 3 6232 3351 Email: metadata at aad.gov.au Contact Address: Australian Antarctic Division 203 Channel Highway City: Kingston Province or State: Tasmania Postal Code: 7050 Country: Australia

Distribution

Distribution Media: HTTP

Distribution Size: 24 kb

Distribution Format: word, csv, excel

Fees: free

Personnel

ADELE PILE

Role: INVESTIGATOR

Role: TECHNICAL CONTACT

Role: DIF AUTHOR

Phone: +61 2 9351 2440

Fax: +61 2 9351 2558

Email: apile at bio.usyd.edu.au

Contact Address:

School Of Biological Sciences

University of Sydney

RM 202A HAYDON-LAURENCE BLDG A08

City: Sydney

Province or State: New South Wales

Postal Code: 2006

Country: Australia

Publications/References

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

Creation and Review Dates

DIF Creation Date: 2003-05-26

Last DIF Revision Date: 2011-07-29

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