Photosynthesis of Marine Macroalgae from Antarctica: Light and Temperature Requirements

Abstract

KeywordsAntarctica. dark respiration. light. marine macroalgae, photosynthesis. temperature. 0.4 to 2.5) and dark respiration (2.5 to 4.1). These features indicate considerable physiological adaptation to the prevailing low light conditions and temperatures of Antarctic waters. In this respect the lower depth distribution limits and the northern distribution boundaries of these species partly depend on the physiological properties described here. AbstractThe photosynthetic performance of macroalgae isolated in Antarctica was studied in the laboratory. Species investigated were the brown algae HimontothalIus qrandifolius, Desmarestia anceps, Ascoseira mirabilis, the red algae Palmaria decipiens, Iridaea cordata, Gigartina skottsberqii, and the green algae Enteromorpha bulbosa, Acrosiphonia arcta. Ulothrix subflaccida and U. implexa. Unialgal cultures of the brown and red algae were maintained at O°C. the green algae were cultivated at 10°C. I K values were between 18 and 53 pmol m -2 S-I characteristic for low light adapted algae. Only the two Ulothrix species showed higher I K values between 70 and 74pmol m-2 S-I. Photosynthesis compensated dark respiration at very low photon fluence rates between 1.6 and 10.6 pmol m-2 S-I. Values of a were high: between 0.4 and L'l umol O 2 g-I FW h-I (pmol m-2 S-I)-I in the brown and red algae and between 2.1 and 4.9 pmol O 2 s' FW h-I (pmol m-2 S-I)-1 in the green algal species. At O°C Pmax values of the brown and red algae ranged from 6.8 to 19.1pmol O 2 g-I FW h-I and were similarly high or higher than those of comparable Arcticcold temperate species. Optimum temperatures for photosynthesis were 5 to 10°C in A. mirabilis. 10°C in H. qrondifolius. 15°C in G. skottsberqii and 20°C or higher in D. anceps and I. cordata. P: R ratios strongly decreased in most brown and red algae with increasing temperatures due to different Q IO values for photosynthesis a:Chi: OW: FW: Ie:P m ax : P: R ratio: P us I curve: QIO: Abbreviations and Symbols initial slope in the linear range of the P us I curve (photosynthetic efficiency) chlorophyll dry weight fresh weight photosynthetic light compensation point photon fluence rate. at which the linear branch of the P us I curve and saturation plateau intersect (initial saturation of photosynthesis) light saturated net photosynthesis photosynthesis: respiration ratio photosynthesis us irrandiance curve ratio of reaction rates at (t + 10)°C and t°C

Exposure to ultraviolet radiation delays photosynthetic recovery in Arctic kelp zoospores

“…The decreasing I k from the mid-to high-latitudes corresponds to the decreasing solar irradiance from the equator to the polar region. A similar relation has been demonstrated in adult macrothalli of seaweeds from polar to tropical regions (Lüning 1990;Wiencke et al 1993;Weykam et al 1996). The photosynthesis-irradiance parameters determined here reflect the depth distribution of the adult sporophytes.…”

Temperature effects on respiration and photosynthesis in three diatom-dominated benthic communities

“…The authors hypothesize that a high Q 10 can be seen as a response to high water-temperature variability and, hence, the authors ascribe the higher Q 10 for the respiration to a more efficient acclimation of heterotrophic compared to phototrophic organisms. Similar observations have been made in temperate planktonic communities (Lefèvre et al 1994, Robinson 2000 and for Antarctic macroalgae (Wiencke et al 1993). The observations have generally been explained by a stronger and more rapid physiological acclimation of heterotrophic metabolism compared to photosynthesis during short-term temperature variations.…”

Life strategy, ecophysiology and ecology of seaweeds in polar waters

“…Maximum photosynthetic rates of endemic Antarctic species are at a temperature of 0°C similar to values from temperate species measured at higher temperatures (Drew 1977;Thomas and Wiencke 1991;Wiencke et al 1993;Weykam et al 1996;Eggert and Wiencke 2000). Moreover, the temperature optima for photosynthesis at least in some species from the Antarctic are well below values determined in temperate species.…”

“…For comparison, in cold-and warm-temperate species optimum values of 20-25°C and 25-35°C were determined, respectively (Lü ning 1990). The temperature optima for respiration are clearly above the optima for photosynthesis but temperatures higher than 30°C have never been tested in Antarctic seaweeds (Drew 1977;Wiencke et al 1993;Eggert and Wiencke 2000). Photosynthesis:respiration ratios are highest at the lowest tested temperature, 0°C, and decrease with increasing temperatures due to different Q10 values for photosynthesis (1.4-3.5) and respiration (2.5-5.1).…”

“…Moreover, the temperature optima for photosynthesis at least in some species from the Antarctic are well below values determined in temperate species. The lowest temperature optima have been determined in the brown algae Ascoseira mirabilis (1-10°C) and Himantothallus grandifolius (10-15°C; Drew 1977;Wiencke et al 1993). The red algae Ballia callitricha and Gigartina skottsbergii also exhibit values between 10 and 15°C, whereas Kallymenia antarctica, Gymnogongrus antarcticus and Phyllophora ahnfeltioides exhibit broad optima between 10 and 20 (to 25)°C (Eggert and Wiencke 2000).…”