Effect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms
Although algal growth in the iron-deficientSouthern Ocean surface waters is generally low, there isconsiderable evidence that winter sea ice contains highamounts of iron and organicmatter leading to ice-edge bloomsduring austral spring. We used field observations and shipbasedmicrocosm experiments t...
| Published in: | Polar Biology |
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| Main Authors: | , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Springer-Verlag
2013
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| Subjects: | |
| Online Access: | https://doi.org/10.1007/s00300-013-1368-7 http://ecite.utas.edu.au/86451 |
| Summary: | Although algal growth in the iron-deficientSouthern Ocean surface waters is generally low, there isconsiderable evidence that winter sea ice contains highamounts of iron and organicmatter leading to ice-edge bloomsduring austral spring. We used field observations and shipbasedmicrocosm experiments to study the effect of theseeding by sea ice microorganisms, and the fertilization byorganic matter and iron on the planktonic community at theonset of spring/summer in the Weddell Sea. Pack ice was amajor source of autotrophs resulting in a ninefold to 27-foldincrease in the sea ice-fertilized seawater microcosm comparedto the ice-free seawater microcosm. However, heterotrophswere released in lower numbers (only a 2- to 6-foldincrease). Pack ice was also an important source of dissolvedorganic matter for the planktonic community. Small algae(\10 lm) and bacteria released frommelting sea icewere ableto thrive in seawater. Field observations show that the supplyof iron from melting sea ice had occurred well before ourarrival onsite, and the supply of iron to the microcosms wastherefore low. We finally ran a sequential melting experimentto monitor the release of ice constituents in seawater.Brine drainage occurred first and was associated with therelease of dissolved elements (salts, dissolved organic carbonand dissolved iron). Particulate organic carbon and particulateiron were released with low-salinity waters at a later stage. |
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