남극 하계 드레이크 해협의 미세생물 먹이망에서 종속영양 미소형 및 소형플랑크톤의 역할 = Trophic Role of Heterotrophic Nano- and Microplankton in the Pelagic Microbial Food Web of Drake Passage in the Southern Ocean during Austral Summer

다국어 초록 (Multilingual Abstract)

To elucidate the trophic role of heterotrophic nano- and microplankton (HNMP), we investigated their biomass, community structure, and herbivory in three different water masses, namely, south of Polar Front (SPF), Polar Front Zone (PFZ), the Sub-Antarcitc Front (SAF) in the Drake Passage in the Southern Ocean, during the austral summer in 2002. We observed a spatial difference in the relative importance of the dominant HNMP community in these water masses. Ciliates accounted for 34.7% of the total biomass on an average in the SPF where the concentration of chlorophyll-a was low with the dominance of pico- and nanophytoplankton. Moreover, the importance of ciliates declined from the SPF to the SAF. In contrast,heterotrophic dinoflagellates (HDFs) were the most dominant grazers in the PFZ where the concentration of chlorophyll-a was high with the dominance of net phytoplankton. HNMP biomass ranged from 321.9 to 751.4 mgCm-2 and was highest in the PFZ and lowest in the SPF. This result implies that the spatial dynamic of HNMP biomass and community was significantly influenced by the composition and concentration of phytoplankton as a food source. On an average, 75.6%, 94.5%, and 78.9% of the phytoplankton production were consumed by HNMP in the SPF, PFZ, and SAF, respectively. The proportion of phytoplankton grazed by HNMP was largely determined by the composition and biomass of HNMP, as well as the composition of phytoplankton. However, the herbivory of HNMP was one of the most important loss processes affecting the biomass and composition of phytoplankton, particularly in the PFZ. Our results suggest that the bulk of the photosynthetically fixed carbon was likely reprocessed by HNMP rather than contributing to the vertical flux in Drake Passage during the austral summer in 2002.

참고문헌 (Reference)

1 Carmack EC, "Water characteristics of the Southern Ocean south of the Polar Front in A Voyage of Discovery" Pergamon Press 15-41, 1977

2 Busalacchi AJ, "The role of the Southern ocean in global processes: an earth system science approach" 16 : 363-368, 2004

3 Dolan J, "The reliability of grazing rate estimates from dilution experiments: Have we overestimated rates of organic carbon consumption" 1 : 21-36, 2005

4 Wylie JL, "The relative importance of bacteria and algae as food sources for crustacean zooplankton" 36 : 708-728, 1991

5 Azam F, "The ecological role of water-column microbes in the sea" 10 : 257-263, 1983

6 Ward P, "The Southern Antarctic Circumpolar current front: physical and biologic- al coupling at South Georgia" 2183-2202 49 : 2183-2202, 2002

7 Gordon AL, "Structure of Antarctic waters between 20°W and 170°W in Antarctic map folio series, vol 6" American Geography Society 1-10, 1967

8 Froneman PW, "Structure and grazing of the microzooplankton communities of the subtropical convergence and a warm-core eddy in the Atlantic sector of the Southern Ocean" 135 : 237-245, 1996

9 Kopczynska E, "Spring phytoplankton assemblages in the Southern Ocean between Australia and Antarctica" 31 : 77-88, 2007

10 Hanson RB, "Spatial distribution, structure, biomass, and physiology of microbial assemblages across the Southern Ocean frontal zone during the late Austral winter" 49 : 1029-1039, 1985

11 Verity PG, "Relationships between lorica volume, carbon, nitrogen and ATP content of tintinnids in Narragansett Bay" 6 : 859-868, 1984

12 Garrison DL, "Protozooplankton in the Weddell Sea, Antarctica: abundance and distribution in the ice-edge zone" 9 : 341-351, 1989

13 Froneman PW, "Protozooplankton community structure and grazing impact in the eastern Atlantic sector of the Southern Ocean in austral summer 1998" 51 : 2633-2643, 2004

14 Michaels AF, "Primary production, sinking fluxes and the microbial food web" 35 : 473-490, 1988

15 Hansen,PJ, "Prey size selection, feeding rates and growth dynamics of heterotrophic dinoflagellates with special emphasis on Gyrodinium spirale" 114 : 327-334, 1992

16 Levinsen H, "Plankton community structure and carbon cycling on the western coast of Greenland during the stratified summer situation. Heterotrophic dinoflagellates and ciliates" 16 : 217-232, 1999

17 Laubscher RK, "Phytoplankton production and biomass at frontal zones in the Atlantic sector of the Southern Ocean" 13 : 471-481, 1993

18 Calbet A, "Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine system" 49 : 51-57, 2004

19 Moore JK, "Phytoplankton chlorophyll distributions and primary production in the Southern Ocean" 105 : 28709-28722, 2000

20 Edler L, "Phytoplankton and chlorophyll. In: Edler L (ed) Recommendations on methods for marine biological studies in the Baltic Sea" Baltic Marine Biologists Publication 13-25, 1979

21 Veth C, "Physical anatomy of fronts and surface waters in the ACC near the 6°W meridian during austral spring 1992" 44 : 23-49, 1997

22 Hansen PJ, "Phagotrophic mechanisms and prey selection in free-living dinoflagellates" 46 : 382-389, 1999

23 Orsi AH, "On the meridional extent and fronts of the Antarctic Circumpolar Current" 42 : 641-673, 1995

24 Sommer US, "Near surface nutreint and phytoplankton distribution in the Drake Passage during early December" 6 : 107-110, 1986

25 Caron DA, "Microzooplankton herbivory in the Ross Sea, Antarctica" 47 : 3249-3272, 2000

26 Grattepanche JD, "Microzooplankton herbivory during the diatom-Phaeocystis spring succession in the eastern English Channel" 404 : 87-97, 2011

27 Verity PG, "Microzooplankton grazing of primary production at 140°W in the equatorial Pacific" 43 : 1227-1255, 1996

28 Tsuda A, "Microzooplankton grazing in the surface water of the Southern ocean during an austral summer" 18 : 240-245, 1997

29 Safi KA, "Microzooplankton composition, biomass and grazing rates along the WOCE SR3 line between Tasmania and Antarctica" 54 : 1025-1041, 2007

30 Burkill PH, "Microzooplankton and their role in controlling phytoplankton growth in the marginal ice zone of the Bellingshausen Sea" 42 : 1277-1290, 1995

31 Klaas C, "Microprotozooplankton distribution and their potential grazing impact in the Antarctic Circumpolar Current" 44 : 375-393, 1997

32 Strom SL, "Microplankton growth, grazing, and community structure in the northern Gulf of Mexico" 130 : 229-240, 1996

33 Pedrós-Alió C, "Microbial plankton across Drake Passage" 16 : 613-622, 1996

34 Legendre L, "Microbial food webs and the export of biogenic carbon in the oceans" 9 : 69-77, 1995

35 Vincent WF, "Microbial ecosystems of Antarctica" Cambrigae University Press 320-, 1988

36 Archer SD, "Microbial dynamics in coastal waters of east Antarctica: herbivory by heterotrophic dinoflagellates" 139 : 239-255, 1996

37 Selph KE, "Microbial community composition and growth dynamics in the Antarctic Polar Front and seasonal ice zone during late spring 1997" 48 : 4059-4080, 2001

38 Brown SL, "Microbial community abundance and biomass along a 180° transect in the equatorial Pacific during an El Niño- Southern oscillation cold phase" 108 : 8139-, 2003

39 Bernard KS, "Mesozooplankton community structure and grazing impact in the Polar Front Zone of the south Indian Ocean during austral summner 2002" 26 : 268-275, 2003

40 Pearce I, "Marine microbial ecology in the sub- Antarctic Zone: Rate of bacterial and phytoplankton growth and grazing by heterotrophic protists" 58 : 2248-2259, 2011

41 Kang H-K, "Length and weight relationship of Acartia steueri (Copepoda: Calanoida) in Ilkwang Bay, Korea" 30 : 906-908, 1997

42 Kivi K, "Late winter microbial communities in the western Weddell Sea (Antarctica)" 14 : 389-399, 1994

43 Landry MR, "Initiation of the spring phytoplankton increase in the Antarctic Polar Front Zone at 170°W" 106 : 13903-13915, 2001

44 Sherr EB, "Heterotrophic protists in the central Arctic ocean" 44 : 1665-1682, 1997

45 Dubischar CD, "Grazing impact of copepods and salps on phytoplankton in the Atlantic sector of the Southern Ocean" 44 : 415-433, 1997

46 Holm-Hansen O, "Factors influencing the distribution, biomass, and productivity of phytoplankton in the Scotia Sea and adjoining waters" 51 : 1333-1350, 2004

47 Landry MR, "Estimating the grazing impact of marine micro-zooplankton" 67 : 283-288, 1982

48 Longhurst AR, "Ecological geography of the sea" Academic Press 398-, 1998

49 Zhou M, "Dynamics of the current system in the southern Drake Passage" 57 : 1039-1048, 2010

50 Yang EJ, "Distribution and structure of heterotrophic protists communities in the northeast equatorial Pacific Ocean" 146 : 1-15, 2004

51 Becquevort S, "Differences of the protozoan biomass and grazing during Spring and Summer in the Indian sector of the Southern Ocean" 23 : 309-320, 2000

52 Pakhomov EA, "Comparative structure of the macrozooplankton/micronekton communities of the Subtropical and Antarctic Polar Fronts" 111 : 155-169, 1994

53 Børsheim KY, "Cell volume to cell carbon conversion factors for a bacterivorous Monas sp. enriched from seawater" 36 : 171-175, 1987

54 Menden-Deuer S, "Carbon to volume relationships for dinoflagellates, diatoms and other protist plankton" 45 : 569-579, 2000

55 El-Sayed SZ, "Biological aspects of the pack-ice ecosystem in Symposim on Antarctic ice and water masses" Scientific communications on Antarctic Research 35-54, 1971

56 Froneman PW, "Biogeographic study of the planktonic communities of the Prince Edward Islands (Southern Ocean)" 20 : 653-669, 1998

57 Talley LD, "Antarctic Intermediate Water in the South Atlantic in The South Atlantic: present and past circulation" Springer-Verlag 219-238, 1996

58 Putt M, "An experimentally determined carbon: volume ratio for marine “oligotrichous” ciliates from estuarine and coastal waters" 34 : 1097-1103, 1989

59 Hewes CD, "Alternative carbon pathways at lower trophic levels in the Antarctic food web in Antarctic nutrient cycles and food webs" Springer 277-283, 1985