Climate change and carbon gain in Antarctic mosses
Entry ID: AAS_2780

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Summary
Abstract: Metadata record for data from AAS (ASAC) project 2780.

Public Summary
The distribution of plants in Antarctica is chiefly limited by the availability of water and sufficiently high temperatures. This project assesses and simulates variation in these factors as experienced by Antarctic moss species, measures how mosses physiologically respond to temperature and moisture changes, and how they will fare in possible future climate scenarios.

Project objectives:

The objectives of this project are:

1) To assess and monitor the seasonal and inter-seasonal variation in temperature and moisture regimes of moss vegetation in continental Antarctica

2) To assess the response of Antarctic moss species to the interaction of moisture and temperature, and different cycles of freezing/thawing and drying/wetting

3) To assess the physiological response of Antarctic moss species to simulated climate change by experimental warming in the field

4) To provide baseline data for modelling the productivity of moss vegetation in response to moisture/temperature interactions, and the possible response of vegetation to short- and long-term changes in climatic patterns in continental Antarctica

Background

The distribution of plants in Antarctica is chiefly limited by the availability of water, nutrients, and temperatures that are sufficiently high to allow the plant to physiologically operate, as well as to provide water in liquid form. Water availability and temperature are tightly linked. Where plants have access to liquid water, a 'window' is created where the plant can acquire carbon and grow.

In the arid climate of eastern continental Antarctica, mosses can occur in areas where mild temperatures during part of the year allow snow or ice to melt and provide the necessary water for carbon acquisition and growth. When water becomes scarce, mosses desiccate and usually survive dry periods until the next 'window of opportunity' opens.

Moss growth is limited by the number and duration of such 'window' periods. There are, however, trade-offs; adjusting to repeated freezing and thawing or drying and re-wetting often reduces the photosynthetic performance of mosses (Kennedy 1993, Lovelock et al. 1995a,b, Robinson et al. 2000). It has been suggested for mosses from other xeric environments that carbon balance limits the distribution of desiccation-tolerant mosses where repeated drought alternates with short wetting periods (Alpert and Oechel 1985). Studies of photosynthetic performance during dehydration (Robinson et al. 2000) or after re-wetting (Schlensog et al. 2004, Wasley 2004, Wasley et al submitted, Schortemeyer, Siebke, Medek and Ball, unpublished data from AAD project 2544) show considerable differences between moss species in the timing of the decline or increase in photosynthesis during drying or after re-wetting, respectively. Some species recover their photosynthetic competence after re-wetting more rapidly than others, and some species lose their photosynthetic competence faster during drying. In addition, cushion size will affect drying and wetting patterns and has been shown to influence the response of photosynthesis to drying and wetting (Zotz et al. 2000). Differential responses of moss species to freezing and drying cycles will influence the comparative performance of species and ultimately species distribution and vegetation composition.

There are good temperature records that extend for more than half a century for a number of sites in continental Antarctica. However, temperature data gathered by weather stations often do not reflect the temperatures of soil or ice surfaces, and importantly, of moss cushions or turfs, which can be substantially warmer than the ambient air temperature (Melick and Seppelt 1997).

While maritime Antarctica shows clear warming trends over the last 50 years (Turner et al. 2005), the patterns for continental Antarctica are less clear. Melick and Seppelt (1997) have suggested a long-term drying pattern for the Windmill Islands region, consistent with a decrease in moss and an increase in lichen vegetation. Inter-annual variation in temperature and moisture can be highly variable and often obscure long-term trends. Whichever way temperature, precipitation and wind patterns develop, they will greatly affect vegetation that is at the edge of its distribution, in a tightly balanced system in the world's most marginal sites for terrestrial plant life.

Mosses are (together with lichens) the principal component of continental Antarctic vegetation. To assess the response of mosses to changes in temperature and moisture during a season, these factors must be monitored at the moss level. This project proposes to monitor moisture and temperature in several moss species along moisture gradients near Casey Station (Wilkes Land). We will measure the physiological response of the different species to different regimes of freezing, thawing, drying, and wetting, in field-based free-air heating experiments as well as in controlled laboratory environments.

Taken from the 2009-2010 Progress Report:

Progress against objectives:

All preparations for the planned experiments were made, including construction, purchase and testing of equipment. Unfortunately, the research program had to be postponed because unusually warm temperatures caused the flights to be cancelled and consequently we were not able to travel to Casey.

Taken from the 2010-2011 Progress Report:

Progress against objectives:
All preparations for the planned experiments were made, including testing of equipment. Unfortunately, the research program had to be postponed because unusually warm temperatures caused the flights to be cancelled and consequently we were not able to travel to Casey.

Related URL
Link: GET DATA
Description: Download point for the data


Link: GET DATA
Description: Download point for the winter re-activation dataset


Link: VIEW PROJECT HOME PAGE
Description: Public information for ASAC project 2780


Link: VIEW RELATED INFORMATION
Description: Citation reference for this metadata record and dataset.


Geographic Coverage
 N: -66.27 S: -66.3  E: 110.55  W: 110.5

Temporal Coverage
Start Date: 2009-09-30
Stop Date: 2011-03-31


Location Keywords
CONTINENT > ANTARCTICA
GEOGRAPHIC REGION > POLAR


Science Keywords
ATMOSPHERE >ATMOSPHERIC TEMPERATURE >AIR TEMPERATURE    [Definition]
BIOSPHERE >VEGETATION >CARBON    [Definition]
CRYOSPHERE >SNOW/ICE >FREEZE/THAW    [Definition]
TERRESTRIAL HYDROSPHERE >SNOW/ICE >FREEZE/THAW    [Definition]
BIOLOGICAL CLASSIFICATION >PLANTS >MOSSES/HORNWORTS/LIVERWORTS    [Definition]


ISO Topic Category
BIOTA
CLIMATOLOGY/METEOROLOGY/ATMOSPHERE
ENVIRONMENT


Platform
FIELD SURVEYS    [Information]
LABORATORY    [Information]
FIELD INVESTIGATION    [Information]


Quality
The values provided in temporal and spatial coverage are approximate only.

Taken from the 2009-2010 Progress Report:

Variations to work plan or objectives:
One member of the research team, Dr Sharon Robinson, travelled to Casey for work on her other projects in advance of our intended arrival. She was shocked to discover that the mosses that we had planned to use for our research were either dead or in extremely poor condition, for unknown reasons. She sent us photos, and the damage is consistent with freeze-induced injury, although other factors could also contribute. In Canberra, we checked the weather records and were surprised to find that there had been an unusually warm period at Casey during the winter of 2009. Specifically, during the week of 13 July, air temperatures rose from -27C to +3C and remained at summer temperatures for a week. It also rained during this period. Then temperatures plunged rapidly back to -27C. We hypothesised that the week of unseasonally warm air temperatures coupled with rainfall and little snow cover, may have induced the mosses to deacclimate, making them vulnerable to freeze-induced injury upon rapid return of winter conditions. Such a pattern would be consistent with the wide scale freeze-induced damage that has been observed recently in vegetation of other cold climate systems. Sharon collected samples of Ceratodon, Shistidium and Bryum which are currently under cultivation at ANU. We are attempting to test the hypothesis by measuring the extent to which the mosses vary tolerance of freezing temperatures between summer and winter conditions, and assessing the response of winter-acclimated moss to a simulated winter warming event under controlled conditions, duplicating as close as possible the sequence of temperatures that occurred during the winter warming event at Casey in July 2009.

We are hoping that we will have sufficient material left over from the above experiment to conduct some studies on physiological bases of interspecific differences in tolerance to freezing and dehydration by the three main moss species collected at Casey.

Taken from the 2010-2011 Progress Report:

Field work:
No field work was undertaken as we were not able to travel to Casey.


Access Constraints
Copies of the data, including detailed readme documents are available for download from the provided URL.

However, the winter re-activation dataset is not yet publicly available, as it has not yet been published.


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 http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_2780 when using these data.


Keywords
moss
carbon gain
freeze-thaw
climate change


Data Set Progress
IN WORK


Data Center
Australian Antarctic Data Centre, Australia    [Information]
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: 45 kb
Distribution_Format: Excel, text
Fees: Free

Distribution_Media: HTTP
Distribution_Size: 52 kb
Distribution_Format: Excel, pdf
Fees: Free


Personnel
MARILYN BALL
Role: INVESTIGATOR
Role: TECHNICAL CONTACT
Phone: +61 2 6125 5057
Email: marilyn.ball at anu.edu.au
Contact Address:
Australian National University
Research School of Biology
GPO Box 475
City: Canberra
Province or State: ACT
Postal Code: 2601
Country: Australia


JACK EGERTON
Role: TECHNICAL CONTACT
Phone: +61 2 6125 0606
Email: Jack.Egerton at anu.edu.au
Contact Address:
Plant Science Division
Australian National University
RN Robertson Building
46 Biology Place
City: Canberra
Province or State: ACT
Postal Code: 0200
Country: Australia


DAVE J. CONNELL
Role: DIF AUTHOR
Phone: +61 3 6232 3244
Fax: +61 3 6232 3351
Email: dave.connell at aad.gov.au
Contact Address:
Australian Antarctic Division
203 Channel Highway
City: Kingston
Province or State: Tasmania
Postal Code: 7050
Country: Australia



Creation and Review Dates
DIF Creation Date: 2010-07-12
Last DIF Revision Date: 2014-01-10

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