Photosynthetic Parameters, Irradiance, Biooptical Properties and Production Estimates in the Western Ross Sea

Lazzara, Luigi; Saggiomo, Vincenzo; Innamorati, Mario; Mangoni, Olga; Massi, Luca; Mori, Giovanna; Nuccio, Caterina

doi:10.1007/978-3-642-59607-0_21

Cited by 8 publications

(10 citation statements)

References 33 publications

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“…The lowest rates were observed at those stations with the thickest cover of snow (Station 009, 0.07 m) and sea ice (Station 013, 0.93 m). The values for P * m observed during our study are intermediate between the higher rates typically reported for phytoplankton in the water column of the Ross Sea [ Palmisano et al , 1986; Smith et al , 1996; Lazzara et al , 2000] and the lower rates for microalgae growing in land‐fast sea ice of McMurdo Sound [ Palmisano et al , 1987b; Arrigo et al , 1993; Robinson et al , 1995] and in the Terra Nova Bay sector of the Ross Sea [ Guglielmo et al , 2000]. They are within the range of values (0.09–1.20, mean 0.56) measured for annual ice floes in the Weddell Sea [ Lizotte and Sullivan , 1991], which are significantly higher than measured in Ross Sea fast ice communities (see review by Lizotte and Sullivan , [1992]).…”

Section: Resultscontrasting

confidence: 87%

Physical control of chlorophyll a, POC, and TPN distributions in the pack ice of the Ross Sea, Antarctica

et al. 2003

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[1] The pack ice ecosystem of the Ross Sea was investigated along a 1470-km northsouth transect during the spring 1998 oceanographic program Research on OceanAtmosphere Variability and Ecosystem Response in the Ross Sea (ROAVERRS). Snow and sea ice thickness along the transect varied latitudinally, with thinner snow and ice at the northern ice edge and thin new ice in the vicinity of the Ross Sea polynya. Relative to springtime observations in other sea ice regions, algal chlorophyll a (Chl a) concentrations were low. In contrast, particulate organic carbon (POC), total particulate nitrogen (TPN), and POC:Chl a were all high, indicating either that the ice contained substantial amounts of detritus or nonphotosynthetic organisms, or that the algae had a high POC:Chl a ratio. The abundance of Chl a, POC, and TPN in the sea ice was related to ice age and thickness, as well as to snow depth: older ice had thinner snow cover and contained higher algal biomass while new ice in the polynya had lower biomass. Older pack ice was dominated by diatoms (particularly Fragilariopsis cylindrus) and had vertical distributions of Chl a, POC, and TPN that were related to salinity, with higher biomass at the ice-water interface. Fluorescence-based measurements of photosynthetic competence (Fv/Fm) were higher at ice-water interfaces, and photosynthesis-irradiance characteristics measured for bottom ice algae were comparable to those measured in pack ice communities of other regions. Nutrient concentrations in extracted sea ice brines showed depletion of silicate and nitrate, depletion or regeneration of phosphate and nitrite, and production of ammonium when normalized to seawater salinity; however, concentrations of dissolved inorganic nitrogen, phosphorous, and silica were typically above levels likely to limit algal growth. In areas where pack ice and snow cover were thickest, light levels could be limiting to algal photosynthesis. Enrichment of d 13 C-POC in the sea ice was correlated with the accumulation of POC, suggesting that carbon sources for photosynthesis might shift in response to decreasing CO 2 supply. Comparisons between new ice and underlying waters showed similar algal species dominance (Phaeocystis antarctica) implying incorporation of phytoplankton, with substantially higher POC and TPN concentrations in the ice.

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Section: Resultscontrasting

confidence: 87%

Physical control of chlorophyll a, POC, and TPN distributions in the pack ice of the Ross Sea, Antarctica

et al. 2003

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“…The E k values were significantly different, suggesting that mixing within the euphotic zone was not rapid enough to remove biological differences that had been established. However, they are comparable to most other measurements made for polar phytoplankton (Smith & Sakshaug 1990, Lazzara et al 2000. The results from the laboratory experiments also suggest that different irradiance regimes result in different states of acclimation.…”

Section: Discussionsupporting

confidence: 87%

“…Their study suggested increased cellular accessory pigments or possible enhancement of electron flow between photosystems as the possible causes for enhanced photosynthetic efficiency at lower irradiance levels. The HPLC data from both cultures in the present study demonstrated that the concentrations of accessory pigments increased with decreasing irradiance (Table 4) ] overlap those of the Bransfield Strait study, even though these cruises experienced different irradiance conditions, supporting the conclusion that Antarctic phytoplankton are well adapted to low irradiance regimes (Palmisano et al 1986, Sakshaug & Holm-Hansen, 1986, Figueiras et al 1998, Lazzara et al 2000.The E k values of this study also support the conclusion that these species are well adapted to a low-irradiance regime. The field results show that at 1% E 0 the assemblages had low E k (an estimate of the optimal values at the different irradiance levels in the field.…”

supporting

confidence: 82%

“…Brightman & Smith (1989) also found that Antarctic phytoplankton were well adapted to low irradiance. They measured photosynthetic efficiencies ranging from 0.01 to 0.06 mg C (mg chl a) ] overlap those of the Bransfield Strait study, even though these cruises experienced different irradiance conditions, supporting the conclusion that Antarctic phytoplankton are well adapted to low irradiance regimes (Palmisano et al 1986, Sakshaug & Holm-Hansen, 1986, Figueiras et al 1998, Lazzara et al 2000.…”

Section: Discussionmentioning

confidence: 63%

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Photosynthesis/irradiance relationships in the Ross Sea, Antarctica, and their control by phytoplankton assemblage composition and environmental factors

Hilst¹,

Smith²

2002

Mar. Ecol. Prog. Ser.

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The photosynthetic parameters of natural phytoplankton assemblages from the Ross Sea, Antarctica, as well as unialgal cultures of the diatom Pseudonitzschia sp. and the colonial haptophyte Phaeocystis antarctica were investigated to determine if differential responses to irradiance could explain the distribution of phytoplankton in the Ross Sea. Field assemblages had photosynthetic responses that suggested acclimation to low irradiance levels, and the initial rate of photosynthesis per unit chlorophyll (α) and the theoretical maximum rate of production (P , respectively. An increase in both α and P B max were noted as the season progressed. However, no differences existed between the photosynthetic responses of phytoplankton assemblages dominated by diatoms and those dominated by P. antarctica. A significant influence of irradiance (reflected in changes in α and the photoadaption index E k ) was observed in the field observations, and this effect was corroborated by laboratory experiments. The carotenoid accessory pigment 19'-hexanoyloxyfucoxanthin in P. antarctica also varied with irradiance, but fucoxanthin did not. These results suggest that the spatially distinct distribution of P. antarctica and diatoms that is often observed in the Ross Sea probably does not result simply from different photosynthetic responses, but from a complex series of controls, potentially including trace metal effects, vertical mixing, and other factors. KEY WORDS: Photosynthesis · Diatoms · Phaeocystis · Accessory pigments Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 226: [1][2][3][4][5][6][7][8][9][10][11][12] 2002 phyte, is found primarily in the south central polynya in spring, and diatoms generally become dominant during summer in the western coastal region. While some locations are clearly dominated by a single form both in terms of numbers and biomass, many locations also represent mixtures of the 2 major groups (and others: Smith & Asper 2001). P. antarctica remains as an important constituent of the phytoplankton throughout the growing season in the south central Ross Sea, although by mid-summer its biomass has decreased and its physiological state is approaching senescence (Smith & Asper 2001). On the other hand, diatoms continue to grow at low rates over much of the entire region (Smith et al. , 1999.The causes for these spatially distinct distributions remain controversial. Past studies have not demonstrated differences in the 2 chemical and physical environments, although mixed layers may be slightly shallower in the west due to greater in situ ice melt and stratification (Arrigo et al. 1999). In contrast, Smith & Asper (2001) compared mixed layer depths of stations dominated by diatoms and Phaeocystis antarctica and found no difference between the 2 taxa in either spring or summer. Mixed layers of ca 30 m are formed in the south central region (along with ice-free conditions) and persist longer (from November through early March: Smith et al. 2000) than t...

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“…Finally the integrated sympagic biomass values at Terra Nova Bay, up to 280 mg m -2 , were in the upper range of those reported from thirteen cruises in the Southern Ocean (Dieckmann et al 1998), and in the review of Arrigo (2003, table 5.1), for bottom-ice communities. Interestingly, these values are even higher than the maximums reached in the water column integrated biomass observed at Terra Nova Bay (Lazzara et al 2000).…”

Section: Discussionmentioning

confidence: 63%

Light environment and seasonal dynamics of microalgae in the annual sea ice at Terra Nova Bay, Ross Sea, Antarctica

et al. 2007

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Abstract:We investigated the physical conditions of the Spring pack ice environment at Terra Nova Bay to understand their influence on the structure and physiology of sympagic microalgae. Bio-optical methods were used to study the availability and spectral quality of solar radiation, both inside and underneath the ice cover. Pack ice thickness was around 2.5 m, with a temperature between -2 and -7°C. On average, only 1.4% of surface PAR penetrated to the bottom ice and less than 0.6% below platelet ice level. Surface UV-B radiation under the bottom ice was 0.2-0.4%. Biomass concentrations up to 2400 mg Chl a m -3 , dominated by two species of diatoms (Entomoneis kjellmannii and Nitschia cf. stellata), showed marked spatial and temporal patterns. Maximum values were in the platelet ice during the first half of November, and in the bottom ice two weeks later. Strong shade adaptation characteristics emerged clearly and explained the relevant abundance of microalgae within the sea ice, with specific absorption coefficients (a*) as low as 0.005 m 2 (mg Chl a) -1 and the photo-acclimation index (E k ) in the range of in situ irradiance. The biomass specific production values were low, around 0.12-0.13 mg C mg Chl a -1 h -1 . The hypothesis suggesting bottom ice colonization by platelet ice microalgae is supported here.

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Photosynthetic Parameters, Irradiance, Biooptical Properties and Production Estimates in the Western Ross Sea

Cited by 8 publications

References 33 publications

Physical control of chlorophyll a, POC, and TPN distributions in the pack ice of the Ross Sea, Antarctica

Physical control of chlorophyll a, POC, and TPN distributions in the pack ice of the Ross Sea, Antarctica

Photosynthesis/irradiance relationships in the Ross Sea, Antarctica, and their control by phytoplankton assemblage composition and environmental factors

Light environment and seasonal dynamics of microalgae in the annual sea ice at Terra Nova Bay, Ross Sea, Antarctica

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