Moline, Mark A.

Prezelin, Barbara B.

Scheppe, Kai

Seydel, Keith

English

DigitalCommons@CalPoly

Palmer LTER: Temporal variability in HPLC pigmentation and inorganic nutrient distribution in surface waters adjacent to Palmer Station, December 1991-February 1992 BARBARA B. PREZElIN, MARK MOUNE, KEITH SEYDEL, AND KAr 5cHEPPE Depdrtl1lent of Biological Sciences ,nd MIlrine Scit'l1ct Instilule University of California at Santa Barbara Stln/a Barbara, California 93106 1992 REVIEW A set of nearfield stations were established in waters adjacent to Palmer Station in the austral spring of 1991 (Kirk and Smith 1993). A range of hydrographic, optical, chemical, and biological properties of the water columns at these sites were repeatedly characterized during late austral spring and summer (December 1991-March 1992). The data will be used 10 define patterns and scales of variability for food-chain parameters in the area sur­rounding important nesting and fledgling sites for large popula­tionsai antarctic seabirds. Here, we present our preliminary data on the temporal variability and possible succession of phy­toplankton communities within surfacewaters of the Palmergrid and their correspondance with changes in the availability of major plant nutrients. A zodiac-based sampling strategy was used to collect water samples at five stations (stations A-E) along a transect line from Arthur Harbor out to the lDO-Fathom Line (figure 1). At each station, surface sampleswere collected with as-literGoFlo bottle, transferred toa blackbottle, and returned tothe laboratory where samples were filtered to determine pigmentation by high-perfor­mance liquid chromatography (HPLC). The filtrates of replicate 245 ----------640' 48' S-----------+--------l Hnmitbl --Ce Sou,," Island .~ ., 640" 08' w 640" 46' S,------==-= RgUrtl 1. Locallon 01 tranSEK:t stations (after Defense Mapping Ag­ency "'p "Vk:lnlty of Arthur Harbor"). CHN samples were deep frozen, transported to the Universityol California at Santa Barbara, and analyzed at the Marine Science Analytical Laboratories for inorganic nutrient content Oohnson ct al. 1985). All HPLC analyses were completed in the field, following procedures outlined in Prezelin et aI. (1993a). Some plant pigments are found only in select groups of phytoplankton and can be used. as chemotaxonomic markers. Changes in thetr abundance may indicate a change in the abundance of ph)·­toplankton group (e.g., Smith et at 1987, 1992). 1he significance, range of abundance, and mean concentration (± standard devia­tion) of pigment markers evident in the present field study are summarized in the table. The frequency of sampling is shown in figure 2a as an overlay on a contour plot of temporal/spatial variability in surfacechlo­rophyll Q distribution. It is evident that a series of blooms (With chlorophyll a values greater than 15,000 nanograms per liter) occurred between mid-December and mid-January, with earlier blooms being lower in intensity and spread along a greater distance of the transect line than the last, very intense bloom that occurred off Bonaparte Point. Prior to the blooms, inorganic nutrients were abundant (figures 2j-I), and phytoplankton com­munities appeared dominated by prymnesiophytes and di­noflagellates (figures 2e and 2j). The initiation of the bloom series was coincident with melting of the pack ice, decreasing ice coverage, and a differential rate of decline in surface-water nutrient concentrations (figures 2j-21). Large changes in the ratio of available nitrate;Si(OH)I:PO~ were observed during the pcriod of bloom events and, as has been reported forotherantarctic regions (cf. Sommer 1986, 1988;Smith et a1. 1992), appcared to be an important determinant of short­term variability in phytoplankton distribution and community composition observed at the long-term ecological research p~ gram (LTER) nearfield stations. Diatoms (figure 2d) dominated the first observed bloom, at a time when silicate (figure 2k) and phosphate (figure 21) levels fell sharply, while prymnesiophytes Comparlslon of the range aod mean concentrations of chemotaxonomlc pigment martters present In the surface walers off Palmer Stalion between December 1991 and mid-February 1992 Pigment Chemota~onomic marker lor Chlorophyll a plant biomass Chlorophyll b chlorophytes and/or prasinophytes Chlorophyll c chromophyles Fucoxanttlin diatoms 19' Hexanoyi- prymnesiophytes """""",,,n Peridinin dinonagellales _~osBulanoyl. fucoxanthin Alloxanthin cryptophyles Zeaxanthin cyanobacteria Pr8sinoxanlhin prasinophytes Range (n!:VL) -Mean ± SO Min. Max. (ng/L) 488 to 29,214 4,339 ± 3,068 nel10 1,731 217 ± 94 nel10811 58 ± 105 neI to 28,672 3,332 ± 1,212 neI 10 374 6087 neI to 160 36±43 neI 10 72 20 ± 14 nello7,"7 859 ± 316 nd to 460 53± 16 nelto7,117 172±97 nd • not detectable , mean of all samples in whk:h pigments were detectable ANrARCTICJOURNIIL 246 Figure 2a·l. Contour plots of the spatial and temporal variability In pigment and Inorganic nutrient distribution along the transect line between a) Chlorophyll B b) ChloroPhyll_b --, E o A.L;---....,..:Ji!!....-~-~---' c) Chlorophyll c E.,---.,----'--'-------;-----, D , I· d~ C B I J A '<LLL.j +DEC JANt FEB Pack Ice Rain Event December 1991 and March 1992. Only surface data is reported. (figure 2e) and dinoflagellates (figure 2f) became less abundant. The only other significant phytoplankton group to increase ap­pears to be prasinophytes (figure 2i). In subsequent blooms, we observed major increases in prymnesiophytes, dinoflagellates, cryptophytes (figure 2g), and cyanobacteria (figure Zh). An intense but localized bloom near Palmer in mid-January was not dominated by diatoms, but rather by prymnesiophytes, cyanobacteria, and cryptophytes. The demise of the bloom series was sudden, coincident with a period of heavy rain and with the presence of a larger area of glacial flowering in the waters be­tween station A-e. We observed an associated increase in nitrate and phosphate levels, with silicate abundance relatively un­changed (figures 2j-I). Depth profiles (not shown) also revealed evidence that diatom populations sank out of surface waters. II appears that within a few weeks of the demise of the first series of blooms, the abundance of prymnesiophytes and dinoflagel­lates was increasing again (figures 2a-f), and perhaps advecting in from offshore waters in late February/early March (data not shown). 1992 REVIEW ng/L ""'" "'''''' ''''''' ""'" , >,~ .'" , , d) Fucoxanthln E A.-'-r-= f) Perldlnln E.,-:--------.,-~._--, , A JANt FEB Rain Event +DEC Pack Ice The results indicate that significant changes in phytoplankton abundances and community composition can and do occur on time scales less than a week. Analyses of pigmentation data, in combination with nutrient, optical, and physical data, as well as photophysiological data on phytoplanktonphotosynthetic prop­erties, should provide significant insight into the mechanisms of food-web dynamics and some aspects of biogeochemical cycl­ing in the LTER nearfie1d sampling grid. This report represents Palmer LTER publication #8 and was supported by National Science Foundation grant DPP9Q-1l927. Special thanks is given to Nicolas Boucher and Allen Matlick for their technical assistance. References Johnson, K. S., R. L. Petty, and J. Thomsen. 1985. Flow inja:tion ana~ for seawater micronutrients. In A. Zirino (Ed.), Mappil1g stratl'gies il1 chemicalocesmography. Adwl1ces il1 Chfmlistry Series (American Chemi­cal Society), 209:7-30. ng/l e) Hex-Fucoxanthln E 247 g) AI/oKanth'" E-r..--­h) Zeuanthln E A.L.f.---' I) Praslnoxanthln E ------.------, JANt FEB Rain Event ngll "" "" .00 , " , "" "" , J) NItrate k) Silicate I) Phosphate uMIL " " • , " " " " , L' 0; , E +DEC PaCk Ice FEB Figure 2g-l. Contour plots of the spallal and temporal variability in pigment and inorganic nutrient distribution along the transect line between December 1991 and March 1992. Only surface data Is reported. Prezelin, B. B., N. P. Boucher, M. Moline, E. Stephens, K Seydel, and K Scheppe. 1993. Palmer LTER: Spatial variability in phytoplankton distribution and surface photosynthetic potential within the penin­sula grid. November 1991. Antarctic Journal oflhe U.S.• this issue. Smith, R. C, R. R. Bidigare, B. B. Prezelin, K. S. Baker, and J. M. Brooks. 1987. Optical characterization of primary production across a coastal front. Mslrine Biology, 96:575-591. Smith. R. C, B. B. Prezelin et al. 1992. Ozone depletion: Ultraviolet radiation and phytoplankton biology in antarctic waters. SciPnct, 255:952-959. Sommer, U. 1988. The species composition of antarctic phytoplankton interpreted in tenns of Tilman's competition theory. 0r0>I0gia, 71:464-467. Sommer, U. and H. H. Stabel. 1986. Near surface nutrient and phy. toplankton distribution in the Drake Passage during early December. Polar Biology, 6:107-110. Waters, KJ. and R. C Smith 1993. Palmer LTER: A sampling grid forthe antarctic LTER Program. Antarctic Journal of lhe U.S., this issue. ANTARCTIC JOURNAL 3 248 

Palmer LTER: Temporal Variability in HPLC Pigmentation and Inorganic Nutrient Distribution in Surface Waters Adjacent to Palmer Station, December 1991-February 1992

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Palmer LTER: Temporal Variability in HPLC Pigmentation and Inorganic Nutrient Distribution in Surface Waters Adjacent to Palmer Station, December 1991-February 1992

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