Life Strategy, Ecophysiology and Ecology of Seaweeds in Polar Waters
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Rev Environ Sci Biotechnol DOI 10.1007/s11157-006-9106-z REVIEW Life strategy, ecophysiology and ecology of seaweeds in polar waters C. Wiencke Æ M. N. Clayton Æ I. Go´ mez Æ K. Iken Æ U. H. Lu¨ der Æ C. D. Amsler Æ U. Karsten Æ D. Hanelt Æ K. Bischof Æ K. Dunton Received: 7 March 2006 / Accepted: 8 May 2006 Ó Springer Science+Business Media B.V. 2006 Abstract Polar seaweeds are strongly adapted to present knowledge of seaweeds from both polar the low temperatures of their environment, Ant- regions with regard to the following topics: the arctic species more strongly than Arctic species history of seaweed research in polar regions; the due to the longer cold water history of the Ant- environment of seaweeds in polar waters; biodi- arctic region. By reason of the strong isolation of versity, biogeographical relationships and vertical the Southern Ocean the Antarctic marine flora is distribution of Arctic and Antarctic seaweeds; life characterized by a high degree of endemism, histories and physiological thallus anatomy; tem- whereas in the Arctic only few endemic species perature demands and geographical distribution; have been found so far. All polar species are light demands and depth zonation; the effect of strongly shade adapted and their phenology is salinity, temperature and desiccation on supra- finely tuned to the strong seasonal changes of and eulittoral seaweeds; seasonality of reproduc- the light conditions. The paper summarises the tion and the physiological characteristics of C. Wiencke (&) Æ U. H. Lu¨ der U. Karsten Alfred Wegener Institute for Polar and Marine Institute of Biological Sciences, Research, Am Handelshafen 12, D-27570 Applied Ecology, University of Rostock, Bremerhaven, Germany Albert-Einstein-Strasse 3, D-18051 Rostock, e-mail: [email protected] Germany M. N. Clayton D. Hanelt School of Biological Sciences, Monash University, Biocenter Klein Flottbek, University P.O Box 18, Melbourne, Victoria 3800, Australia of Hamburg, Ohnhorst-Str. 18, D-22609 Hamburg, Germany I. Go´ mez Instituto de Biologı´a Marina, Universidad Austral de K. Bischof Chile, Casilla 567, Valdivia, Chile Institute for Polar Ecology, University of Kiel, Wischhofstr. 1–3, D-24148 Kiel, K. Iken Germany Institute of Marine Science, University of Alaska Fairbanks, O’Neill Bldg., Fairbanks, AK 99775, USA K. Dunton Marine Science Institute, University of Texas at C. D. Amsler Austin, 750 Channel View Drive, Port Aransas, Department of Biology, University of Alabama at TX 78373, USA Birmingham, Birmingham, AL 35294-1170, USA 123 Rev Environ Sci Biotechnol microscopic developmental stages; seasonal of the Arctic Sea’’ (Kjellman 1883) is a taxonomic growth and photosynthesis; elemental and nutri- and biogeographic baseline study. Detailed stud- tional contents and chemical and physical ies on seaweeds from Greenland were made by defences against herbivory. We present evidence Rosenvinge (1898), and in the 20th century by to show that specific characteristics and adapta- Lund (1951, 1959a, b) and Pedersen (1976). tions in polar seaweeds help to explain their Taxonomic information concerning seaweeds ecological success under environmentally extreme from Spitsbergen and the Russian Arctic is also conditions. In conclusion, as a perspective and available in publications by Svendsen (1959), Zi- guide for future research we draw attention to nova (1953; 1955), Vinogradova (1995) and many many remaining gaps in knowledge. others. A very valuable contribution on seaweeds from the north-eastern coast of North America is Keywords Chemical ecology Æ Freezing Æ the book by Taylor (1966; first published 1937). Growth Æ Light Æ Phenology Æ Photosynthesis Æ The first extensive diving studies were performed Polar algae Æ Salinity Æ Seaweeds Æ Temperature by Wilce (1963), Chapman and Lindley (1980) and by Dunton et al. (1982) in the Canadian and Alaskan Arctic. As in Antarctica, diving is an History of seaweed research in the polar regions essential prerequisite for detailed studies on all aspects of seaweed biology and this technique has The first phycological studies in the Arctic and since been widely applied in several regions of the the Antarctic regions took place in the first half Arctic. Since 1991 there has been intensive re- of the 19th century. Studies on Antarctic sea- search on the ecology and ecophysiology of weeds started in 1817 with the work of Gaudi- Arctic seaweeds on Spitsbergen (Hop et al. 2002; chaud, Bory, Montagne, Hooker and Harvey Wiencke 2004). (Godley 1965). Later, between 1882 and 1909, intensive studies were carried out by Skottsberg, Reinsch, Gain, Hariot, Kylin, Hylmo¨ , Foslie and The environment of seaweeds in polar waters others (Papenfuss 1964). After this period of mostly taxonomic and biogeographical investiga- The polar regions are characterized by pro- tions, which culminated in the publication of the nounced seasonal variations of the light regime, catalogue by Papenfuss (1964), numerous diving low temperatures, and long periods of snow and investigations were conducted in West Antarctica ice cover. Littoral seaweed communities are often by, among others, Neushul (1965), De´le´pine et al. strongly impacted by icebergs and sea ice espe- (1966), Lamb and Zimmermann (1977), Moe and cially in areas with high wave action (Klo¨ ser et al. DeLaca (1976), Richardson (1979), Klo¨ ser et al. 1994). Icebergs can run aground in the Antarctic (1996) and in East Antarctica by Zaneveld (1968) down to 600 m depth (Gutt 2001). First-year sea and Cormaci et al. (1997). These studies gave ice has a thickness of up to 2 m, and in the Arctic greater insight into the depth distribution of multi-year ice can reach depths of about 40 m Antarctic seaweeds and allowed more detailed (Gutt 2001). Anchor ice forms on the seabed in studies on the life histories, ecophysiology and shallow waters and can enclose seaweeds espe- ecology of seaweeds from Antarctica. The highly cially in East Antarctica (Miller and Pearse 1991). fragmented information on the seaweeds of The seasons in the sublittoral are characterized Antarctica was summarized recently in a synopsis in polar regions by short periods of favourable by Wiencke and Clayton (2002). light conditions and extended periods of darkness Early algal research in the Arctic started in due to the polar night and sea ice cover in winter 1849 in the Canadian Arctic with Harvey and (Kirst and Wiencke 1995). At the poleward Dickie (Lee 1980). The Russian phycologist distribution limits of seaweeds, at 77° S and Kjellman worked in many places in the Arctic, 80° N, respectively, the annual solar radiation is especially in the Russian Arctic, the northern 30–50% less than in temperate to tropical regions, Bering Sea and Spitsbergen. His book ‘‘The algae and the polar night lasts for about 4 months 123 Rev Environ Sci Biotechnol (Lu¨ ning 1990). At lower latitudes, e.g. close to the thesis as well as the photomorphogenetic devel- northern limit of the Antarctic region, in the opment of the understorey (Salles et al. 1996). South Shetland Islands, daylength varies between The possible impact of enhanced UVB 5 h in winter and 20 h in summer (Wiencke radiation due to stratospheric ozone depletion on 1990a). This extreme light regime has strong primary production of seaweeds is higher during implications for primary productivity in general the spring season, as organisms in the eulittoral and for the seasonal development of seaweeds. In and upper sublittoral zone are already affected by addition the long periods of darkness are further UVB radiation throughout the polar day and tur- extended due to the formation of sea ice. If the bid melt water input occurs only during the sum- ice is also covered by snow, irradiance can be mer season. The strong increase of turbidity due to diminished to less than 2% of the surface value. a discharge of sediments by melt water and gla- Consequently, seaweeds may be exposed up to ciers applies especially to Arctic shorelines in half- about 10 months of darkness or very low light open fjord systems where the water exchange with conditions (Chapman and Lindley 1980; Dunton the clearer oceanic water is retarded (Svendsen 1990; Miller and Pearse 1991; Drew and Hastings et al. 2002). On open coastlines the melt water is 1992; Klo¨ ser et al. 1993). exchanged much faster with clear oceanic water so After sea ice break-up in spring, light pene- that seaweeds are exposed to biologically effective trates deeply into the clear water. On King UVR for longer time periods. George Island (South Shetland Islands) at this The inflow of melt water in summer has con- time average photon fluence rates are 70 lmol siderable effects on the salinity and temperature m–2 s–1 at midday in 30 m depth (Go´ mez et al. regime in inshore waters. During times of calm 1997). On Signy Island (South Orkney Islands) the weather, there is a strong stratification in the euphotic zone, i.e. the 1% depth for photosyn- water body with a layer of fresh water above a thetically active radiation (PAR), was determined layer of denser sea water. However, due to ver- at 29 m (Brouwer 1996). UV-radiation (UVR) tical water mixing by wave action and wind the and blue light are, however, more strongly atten- deeper water zones also become affected and a uated. The 1% depth for UVB radiation, repre- salinity decrease may occur down to about 20 m senting more or less the threshold irradiance of depth (Hanelt et al. 2001). UV-B with the potential to affect primary plant In contrast to the strong seasonal variation in the productivity negatively, is located between 4 and radiation conditions, water temperatures in the 8 m on Spitsbergen (Hanelt et al. 2001; van de sublittoral mostly change only little between – Poll et al. 2002). Later, in summer, coastal waters 1.8°C in winter and +2.0°C in summer, e.g.