Antarctic phytoplankton summer and winter stage indicators
References Ainley, D.C., and C.W. Sullivan. 1989. AMERIEZ 1988: A summary of a winter cruise of the Weddell and Scotia Seas on Polar Duke. Antarctic Journal of the U.S., 24(5). Jeffrey, S.W. 1974. Profiles of photosynthetic pigments in the ocean using thin-layer chromatography. Marine Biology, 26, 101-110. Lewis, M.R., and J.C. Smith. 1983. A small volume, short incubation time method for measurement of photosynthesis as a function of incident irradiance. Marine Ecology Progress Series, 13, 99-102.
AMERIEZ 1988 and ODP Leg 119: Antarctic phytoplankton summer and winter stage indicators GRETA A. FRYXELL, SUNG-Ho KANG, and TIFFANY K. ASHWORTH Depart nient of Oceanography Texas A&M University College Station, Texas 77843-3146
Field work principally from two cruises allowed valuable phytoplankton collections. In the austral summer (December 1987 to February 1988) the drill ship JOIDES Resolution and its service vessel Maersk Master conducted the Ocean Drilling Program (ODP) Leg 119 over the Kerguelen Plateau, in the southern Indian Ocean, and over the antarctic continental shelf into Prydz Bay. During austral winter June to August 1988, the RI V Polar Duke completed two legs into the northern Weddell Sea for the AMERIEZ (Antarctic Marine Ecosystem Research at the Ice-Edge Zone) National Science Foundation program. Quantitative phytoplankton estimations from the water column are being made from both cruises with interesting implications for seasonal dynamics and allowing a continuation of life history interpretations (Fryxell, Reap, and Kang 1988; Fryxell 1989). ODP leg 119 into Prydz Bay. Biological collections were made in Prydz Bay from the Maersk Master (Fryxell and Shipboard Party 1988). A new quantitative method with water-soluble resin (HPMA, 2-hydroxypropyl methacrylate) using filtered samples (Crumpton 1987) was used on board and tested against the classical UtermOhl method (Kang and Fryxell 1989). Since the filter itself is used as part of the mount, there is no actual loss of cells. The recovery of nanoplankton has been particularly interesting because the problem of distinguishing the trophic mode of nanoplankton is a major concern of biological oceanography. The filtering technique was found to be superior to the UtermOhl technique for the nanoplanktonic diatoms, Nitzschia cylindrus (Grunow) Hasle and N. closterium (Ehrenberg) William Smith, and all empty cells, which are assumed to be dead when collected (figure 1). Over 40 diatom species were found in Prydz bay. Estimated numbers of total full diatoms (assumed to be alive when collected) integrated under 1 square meter of the water column, weighted by depth, ranged from 37.6 x 10 to 288 x 10 cells 156
Lizotte, M. P. 1989. Photop/nsiologi and cellular composition of sea ice algae. (Dissertation, University of Southern California at Los Angeles.) SooHoo, J.B., A.C. Palmisano, S.T. Kottmeier, M.P. Lizotte, S.L. SooHoo, and C.W. Sullivan. 1987. Spectral light absorption and quantum yield of photosynthesis in sea ice microalgae and a bloom of Phaeocysf is pouchef ii from McMurdo Sound, Antarctica. Marine Ecology Progress Series, 116, 1-13. Stauber, J.L., and S.W. Jeffrey. 1988. Photosynthetic pigments in fiftyone species of marine diatoms. Journal of Phycology, 24, 158-172.
per square meter, while total empty diatoms (assumed to be dead when collected) ranged from 71.6 x 109 to 122 x 10 cells per square meter. Main components of total full diatoms were small pennate diatoms N. cylindrus, N. closteriuin, and N. curta and larger-celled diatoms Chaetoceros dichaeta, Cli. neglectus, and Corethron criopliilum. AMERIEZ winter cruise. Two legs of the winter cruise on the Polar Duke, out of Punta Arenas, Chile, (4 June to 6 July; and 14 July to 17 August 1988), allowed study of the living phytoplankton winter stages on board ship (figure 2, C/zat'toceros atlanticus Cleve). Quantitative counts were made using the Filter-Transfer-Freeze technique (Hewes and Holm-Hansen 1983). Highest integrated counts of phytoplankton in the top 150 meters were found at the open water station near the iceedge and the lowest counts were found at ice-covered stations on the 40°W transect of the second leg of AMERIEZ 88 (figure 3). Although the integrated numbers of phytoplankton in the open water were intermediate to that of the ice-edge and packice counts, the most concentrated samples of net plankton were collected in open water. Diatoms (full) were a dominant cornINTEGRATED CELLS PER SQUARE METER OCEAN DRILLING PROGRAM (ODP) LEG 119, SITE 740
300 (I)
—J -J W 0
0) 0
200
X >-
0 z W 100 0
W cc LL
[I] A B C D Figure 1. Comparison of mean integrated diatom abundances (cells per square meter) between filtered (HPMA) and settled (Utermähl) techniques for station 8 of Ocean Drilling Program site 740, collected on 27 January 1988 (68 042'S 76039'E) from the Maersk Master collections. A. Total diatoms (full cells). B. Total diatoms (empty cells), C. Nitzschia cylindrus. D. N. closterium.
ANTARCTIC JOURNAL
1 0 1jm
Figure 2. Light micrograph of small chain of Chaetoceros atlanticus, winter form with heavily silicified overlapping setae, alive, taken onboard the Polar Duke, austral winter, 1988. Note rigid winter form and short chain of five cells. No dividing cells. (pim denotes micrometer.)
ponent of the phytoplankton with 74 percent at the open-water station, 43 percent at the ice-edge station, and 93.4 percent at the pack-ice covered station. All empty cells on figure 3 are diatoms. Dominants for these three stations include Pliaeocystis sp. and Nitzschia spp. (section Frac,'illarwpsis). The diatom Eucam pin antarctica: Varieties and life stages. The transect south in the Indian Ocean from Mauritius over the Kerguelen Plateau into Prydz Bay allowed observation of the latitudinal change in oceanic flora. Study of living material Integrated Cells per Square Meter in Top 1 50m of the Water Column 1000
800 C)
600
C) L)
400
C V 200
from this transect and during the austral winter cruise resulted in two new insights into the diatom Lucainpia antarctica (Castracane) Mangin and a renewed interest in its nomenclature (Fryxell, Prasad, and Fryxell 1989): • Two varieties have different distributions, with Eucampia antarctica var. recta close to the ice and the continent and with E. antarctica var. antarctica farther north, or subpolar. • Each variety has a heavily silicified form that resembles a resting spore, but instead it is a winter stage capable of growth (Fryxell and Prasad, in preparation) until the lightly silicified summer form with differing morphology is triggered. Eucam pin antarctica var. antarctica was not found in this material south of 60°S (Fryxell, in preparation) although it could be transported by warm core rings. Not only does the knowledge of the presence of the two varieties serve to clarify the past confusion in both biological and geological literature in regard to conflicting interpretations of the overlapping distribution patterns, but perhaps the two varieties provide indications of a case of early speciation. In this case, the varieties are physiologically isolated by the dynamic biological boundaries presented by the ice edge and the Antarctic Convergence Zone. The geological implication is that the amount of growth, and indirectly the amount of light and/ or ice cover, can be calculated from an index of the morphotypes in the sediment from the proportion of intercalary valves to terminal valves from the original formation of doublets from a vegetative cell. The biological implication is that winter stages and resting spores show parallel evolution; evidence is increasing that resting spores may be secondarily derived and may not be primitive characters. Several clones are in culture, and triggering mechanisms are being tested. We appreciate the onboard collections during the second leg of the AMERIEZ 88 winter cruise by A.K.S.K. Prasad and C. Venn. M.E. Reap and M. Mann gave excellent logistic and program assistance. This work was supported in part by National Science Foundation grant DPP 84-18850, the Ocean Drilling Program, and JOI!USSAC Grant 20200, which are gratefully acknowledged. References Crumpton, W.G. 1987. A simple and reliable method for making permanent mounts of phytoplankton for light and fluorescence microscopy. Limnologii and OcL'alio'rapIn/, 32(5), 1,154-1,159. Fryxell, G.A. 1989. Marine Phvtoplankton at the Weddell Sea ice edge: seasonal changes at the specific level. Polar Biology, 10, 1-8. Fr y xell, G.A. In press. Eiicainpia antarctica (Castracane) Mangin: Complex distribution patterns of the varieties. ODP prcliininarii volutiic. Fryxell, GA., A.K.S.K. Prasad, amd P.A. Fryxell. 1989. In press. Eucainpia antarctica (Castracane) Mangin: Complex nomenclatural and taxonomic history. Taxon, 38(4), 638-640. Fryxell, G.A., and A.K.S.K. Prasad. In preparation. Eucainpia antarctica (Castracane) Mangin var. recta, var. nov.. (Biddulphiaceae, Bacillariophyceae): Life stages at the Weddell Sea ice edge. P/ivcologia. Fryxell, G.A., M.E. Reap, and S.-H. Kang. 1988. Antarctic Phytoplankton: dominants, life stages, and indicators. Antarctic Journal of the U.S., 23(5), 173-175.
Stations Figure 3. Comparison of integrated phytoplankton cells (empty/full) in the top 150 meters. A. Open water (57°59.8'S 40°00.2'W); B. Near ice edge (580 56.6'S 40°00.1'W); C. Within the pack ice (59°46.3'S 40°03.3'W).
1989 REVIEW
Hewes, C.D., and 0. Holm-Hansen. 1983. A method for recovering nanoplankton from filters for identification with the microscope: the filter-transfer-freeze technique. Liinnolo5nj and Oceanography, 28(2), 389-394.
Kang, S.-H., and G.A. Fryxell. 1989. Comparative methods of quantitative analysis of diatoms in water column assemblages in Prydz Bay, Antarctica, ODP Leg 119. E0S, 70(15), 376.
157
AMERIEZ 1988 and ODP Leg 119: Antarctic phytoplankton summer and winter stage indicators GRETA A. FRYXELL, SUNG-Ho KANG, and TIFFANY K. ASHWORTH Depart nient of Oceanography Texas A&M University College Station, Texas 77843-3146
Field work principally from two cruises allowed valuable phytoplankton collections. In the austral summer (December 1987 to February 1988) the drill ship JOIDES Resolution and its service vessel Maersk Master conducted the Ocean Drilling Program (ODP) Leg 119 over the Kerguelen Plateau, in the southern Indian Ocean, and over the antarctic continental shelf into Prydz Bay. During austral winter June to August 1988, the RI V Polar Duke completed two legs into the northern Weddell Sea for the AMERIEZ (Antarctic Marine Ecosystem Research at the Ice-Edge Zone) National Science Foundation program. Quantitative phytoplankton estimations from the water column are being made from both cruises with interesting implications for seasonal dynamics and allowing a continuation of life history interpretations (Fryxell, Reap, and Kang 1988; Fryxell 1989). ODP leg 119 into Prydz Bay. Biological collections were made in Prydz Bay from the Maersk Master (Fryxell and Shipboard Party 1988). A new quantitative method with water-soluble resin (HPMA, 2-hydroxypropyl methacrylate) using filtered samples (Crumpton 1987) was used on board and tested against the classical UtermOhl method (Kang and Fryxell 1989). Since the filter itself is used as part of the mount, there is no actual loss of cells. The recovery of nanoplankton has been particularly interesting because the problem of distinguishing the trophic mode of nanoplankton is a major concern of biological oceanography. The filtering technique was found to be superior to the UtermOhl technique for the nanoplanktonic diatoms, Nitzschia cylindrus (Grunow) Hasle and N. closterium (Ehrenberg) William Smith, and all empty cells, which are assumed to be dead when collected (figure 1). Over 40 diatom species were found in Prydz bay. Estimated numbers of total full diatoms (assumed to be alive when collected) integrated under 1 square meter of the water column, weighted by depth, ranged from 37.6 x 10 to 288 x 10 cells 156
Lizotte, M. P. 1989. Photop/nsiologi and cellular composition of sea ice algae. (Dissertation, University of Southern California at Los Angeles.) SooHoo, J.B., A.C. Palmisano, S.T. Kottmeier, M.P. Lizotte, S.L. SooHoo, and C.W. Sullivan. 1987. Spectral light absorption and quantum yield of photosynthesis in sea ice microalgae and a bloom of Phaeocysf is pouchef ii from McMurdo Sound, Antarctica. Marine Ecology Progress Series, 116, 1-13. Stauber, J.L., and S.W. Jeffrey. 1988. Photosynthetic pigments in fiftyone species of marine diatoms. Journal of Phycology, 24, 158-172.
per square meter, while total empty diatoms (assumed to be dead when collected) ranged from 71.6 x 109 to 122 x 10 cells per square meter. Main components of total full diatoms were small pennate diatoms N. cylindrus, N. closteriuin, and N. curta and larger-celled diatoms Chaetoceros dichaeta, Cli. neglectus, and Corethron criopliilum. AMERIEZ winter cruise. Two legs of the winter cruise on the Polar Duke, out of Punta Arenas, Chile, (4 June to 6 July; and 14 July to 17 August 1988), allowed study of the living phytoplankton winter stages on board ship (figure 2, C/zat'toceros atlanticus Cleve). Quantitative counts were made using the Filter-Transfer-Freeze technique (Hewes and Holm-Hansen 1983). Highest integrated counts of phytoplankton in the top 150 meters were found at the open water station near the iceedge and the lowest counts were found at ice-covered stations on the 40°W transect of the second leg of AMERIEZ 88 (figure 3). Although the integrated numbers of phytoplankton in the open water were intermediate to that of the ice-edge and packice counts, the most concentrated samples of net plankton were collected in open water. Diatoms (full) were a dominant cornINTEGRATED CELLS PER SQUARE METER OCEAN DRILLING PROGRAM (ODP) LEG 119, SITE 740
300 (I)
—J -J W 0
0) 0
200
X >-
0 z W 100 0
W cc LL
[I] A B C D Figure 1. Comparison of mean integrated diatom abundances (cells per square meter) between filtered (HPMA) and settled (Utermähl) techniques for station 8 of Ocean Drilling Program site 740, collected on 27 January 1988 (68 042'S 76039'E) from the Maersk Master collections. A. Total diatoms (full cells). B. Total diatoms (empty cells), C. Nitzschia cylindrus. D. N. closterium.
ANTARCTIC JOURNAL
1 0 1jm
Figure 2. Light micrograph of small chain of Chaetoceros atlanticus, winter form with heavily silicified overlapping setae, alive, taken onboard the Polar Duke, austral winter, 1988. Note rigid winter form and short chain of five cells. No dividing cells. (pim denotes micrometer.)
ponent of the phytoplankton with 74 percent at the open-water station, 43 percent at the ice-edge station, and 93.4 percent at the pack-ice covered station. All empty cells on figure 3 are diatoms. Dominants for these three stations include Pliaeocystis sp. and Nitzschia spp. (section Frac,'illarwpsis). The diatom Eucam pin antarctica: Varieties and life stages. The transect south in the Indian Ocean from Mauritius over the Kerguelen Plateau into Prydz Bay allowed observation of the latitudinal change in oceanic flora. Study of living material Integrated Cells per Square Meter in Top 1 50m of the Water Column 1000
800 C)
600
C) L)
400
C V 200
from this transect and during the austral winter cruise resulted in two new insights into the diatom Lucainpia antarctica (Castracane) Mangin and a renewed interest in its nomenclature (Fryxell, Prasad, and Fryxell 1989): • Two varieties have different distributions, with Eucampia antarctica var. recta close to the ice and the continent and with E. antarctica var. antarctica farther north, or subpolar. • Each variety has a heavily silicified form that resembles a resting spore, but instead it is a winter stage capable of growth (Fryxell and Prasad, in preparation) until the lightly silicified summer form with differing morphology is triggered. Eucam pin antarctica var. antarctica was not found in this material south of 60°S (Fryxell, in preparation) although it could be transported by warm core rings. Not only does the knowledge of the presence of the two varieties serve to clarify the past confusion in both biological and geological literature in regard to conflicting interpretations of the overlapping distribution patterns, but perhaps the two varieties provide indications of a case of early speciation. In this case, the varieties are physiologically isolated by the dynamic biological boundaries presented by the ice edge and the Antarctic Convergence Zone. The geological implication is that the amount of growth, and indirectly the amount of light and/ or ice cover, can be calculated from an index of the morphotypes in the sediment from the proportion of intercalary valves to terminal valves from the original formation of doublets from a vegetative cell. The biological implication is that winter stages and resting spores show parallel evolution; evidence is increasing that resting spores may be secondarily derived and may not be primitive characters. Several clones are in culture, and triggering mechanisms are being tested. We appreciate the onboard collections during the second leg of the AMERIEZ 88 winter cruise by A.K.S.K. Prasad and C. Venn. M.E. Reap and M. Mann gave excellent logistic and program assistance. This work was supported in part by National Science Foundation grant DPP 84-18850, the Ocean Drilling Program, and JOI!USSAC Grant 20200, which are gratefully acknowledged. References Crumpton, W.G. 1987. A simple and reliable method for making permanent mounts of phytoplankton for light and fluorescence microscopy. Limnologii and OcL'alio'rapIn/, 32(5), 1,154-1,159. Fryxell, G.A. 1989. Marine Phvtoplankton at the Weddell Sea ice edge: seasonal changes at the specific level. Polar Biology, 10, 1-8. Fr y xell, G.A. In press. Eiicainpia antarctica (Castracane) Mangin: Complex distribution patterns of the varieties. ODP prcliininarii volutiic. Fryxell, GA., A.K.S.K. Prasad, amd P.A. Fryxell. 1989. In press. Eucainpia antarctica (Castracane) Mangin: Complex nomenclatural and taxonomic history. Taxon, 38(4), 638-640. Fryxell, G.A., and A.K.S.K. Prasad. In preparation. Eucainpia antarctica (Castracane) Mangin var. recta, var. nov.. (Biddulphiaceae, Bacillariophyceae): Life stages at the Weddell Sea ice edge. P/ivcologia. Fryxell, G.A., M.E. Reap, and S.-H. Kang. 1988. Antarctic Phytoplankton: dominants, life stages, and indicators. Antarctic Journal of the U.S., 23(5), 173-175.
Stations Figure 3. Comparison of integrated phytoplankton cells (empty/full) in the top 150 meters. A. Open water (57°59.8'S 40°00.2'W); B. Near ice edge (580 56.6'S 40°00.1'W); C. Within the pack ice (59°46.3'S 40°03.3'W).
1989 REVIEW
Hewes, C.D., and 0. Holm-Hansen. 1983. A method for recovering nanoplankton from filters for identification with the microscope: the filter-transfer-freeze technique. Liinnolo5nj and Oceanography, 28(2), 389-394.
Kang, S.-H., and G.A. Fryxell. 1989. Comparative methods of quantitative analysis of diatoms in water column assemblages in Prydz Bay, Antarctica, ODP Leg 119. E0S, 70(15), 376.
157
