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Effect of Charophytes on Nutrient Cycling in Lake
æµ æ é*, è€é æ¯ *
Takashi ASAEDA and Takeshi FUJINO
This report describes about the effect of Charophytes on nutrient cycling, conducted in Lake Myall, Australia.
Relationships between submerged plants biomass and gyttja layer thickness, decomposition characteristics of
the four dominated species, mechanism of phosphorous accumulation by Chara, UV light effect on plant
biomass are discussed. These results give that both Charophytes and gyttja may play a role of water quality
stabilization. A possibility and condition of applying for Japanese lakes are suggested.
Keywords: Chara, Nutrient Cycling, gyttja, Myall Lake
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Fig.3 Relationship between drymass and water depth
gyttha thicknessvs dry mass
0
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350
400
450
500
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gyttja thickness (m)
dry mass (g/m2)
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Nitella
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Fig.4 Relationship between dry mass and gyttja layer depth
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J A S O N D J F M AM J J A S O ND J F M
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Charophytes biomass vsMriophyllum biomass
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0 50 100 150 200Charophytes biomass (g/m2)
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Fig. 6 Charophytes biomass v.s. Mriophylam biomass
Charophytes biomass vs Najas biomass
0
100
200
300
400
500
0 50 100 150 200 250 300
Charophytes biomass (g/m2)
Naj
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iom
ass (
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Fig. 7 Charophytes biomass v.s. Najas biomass
-3.5
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1) å·æå€å¯Šäºåè, äžéçäžç·šé, æ¥æ¬æ·¡æ°Žçç©åŠ, å
é通, 106-112, 1986.
2) å®æ欣äº, æ¹æ²Œçç©ã®çæ åŠ, å¯æ é€åãšäººã®ç掻
ã«ãµããŠ, å ±ç«åºç, 1998.
3) Agami, M., Beer, S., and Waisel, Y., Growth and
photosyntheis of Najas marina L. as affected by light
intensity. Aquatic Botany, 9, 285-289, 1980.
4) Agami, M., and Y. Waisel, Germination of Najas marina
L., Aquatic Botany, 19, 37-44, 1984.
5) Agami, M., S.Beer, and Y.Waisel, Seasonal variation in
the growth capacity of Najas marina L. as a function of
various water depth at the Yarkon Spring, Israel. Aquatic
Botany, 19, 45-51, 1984.
6) Andrews, M., Davidson, I.R., Andrews, M.E., and Raven,
J.A., Growth of Chara hispida.1. Apical growth and basal
decay. Journal of Ecology, 72, 873-884, 1984.
7) Bastardo, H., Laboratory studies on decomposition of
littoral plants Pol. Arch. Hydrobiol., 26, 267-299, 1979.
8) Beltman, B., and C. Allegrini, Restoration of lost aquatic
plant communities: new habitats for Chara. Netherland
Journal of Aquatic Ecology, 30, 331-337, 1997.
9) Brunberg, A.-K. and P. Blomqvist, Post-glacial,
land-rise induced formation and development of lakes in
he Forsmark Area, central Sweden. Swedish Nuclear Fuel
and Waste Management Co. Technical Report
SKB-TR-00-02, Stockholm, Sweden, 2000.
10) Blindow, I., Decline of charophytes during eutrophcation:
comparison with angiosperms. Freshwater Biology, 28,
9-14, 1992.
11) Borowitzka, M.A., Mechanisms in algal calcification, in
Progress in Phycological Research, 1, Round, F.E. and
Chapman, C.H., Eds, Elsevier/North Holland
Biomedical Press, Amsterdam, New York, 137, 1982.
12) Boyd, C.E., Some aspects of aquatic plant ecology. In
Proceedings of the reservoir Fishery Resources
Symposium. University of Gerogia Press Athens, GA,
114-129, 1967.
13) Carignan, R., and Kalff, J., Phosphorus source for aquatic
weeds: water or sediments? Science, 207, 987-989, 1980.
14) Carignan, R., An empirical model to estimate the relative
importance of roots in phosphorus uptake by aquatic
macrophtes, Canadian Journal of Fisheries and Aquatic
Science, 39, 243-247, 1982.
15) Casanova, M.T., Charopytes, Waterplants, 4th ed. Ed by
G.R.Sainty and S.W.L. Jacobs, Sainty and Associates Pty
Ltd., Potts Point, 2003.
16) Casanova, M.T. and M.A. Brock, Life histories of
charophytes from permanent and temporary wetlands in
倧åæ€ç©ã·ã£ãžã¯ã¢ãæ¹æ²Œå ã®æ é€å¡©ã®åŸªç°ã«äžããåœ±é¿ 164
eastern Australia, Australian Journal of Botany, 47,
383-397, 1999.
17) Fernandez-Alaez, M., C. Fernandez-Alaez, C., and S.
Rodriguez, Seasonal changes in biomass of charophytes in
shallow lakes in the northwest of Spain, Aquatic Botany,
72, 335-348, 2002.
18) Forsberg, C., Phosphorus, a maximum factor in the
growth of Characeae. Nature, 201, 517-518, 1967.
19) Forsberg, C., Environmental conditions of Swedish
charophytes. Symp.Bot. Ups. 18:4. Uppsala University,
Uppsala, Sweden, 1965.
20) Garcia, A., Taxonomy and ecology of Charophytes, 3rd
Australian Algal Workshop, Brisbane, 2001.
21) Hutchinson, G.E., A treatise on limnology, Vol.III.
Limnological Botany. Wiley, New York, 660p., 1975.
22) Kairesalo,T., Jonsson,G.St,. Gunnarson,K., Lindegaard,C.,
and P.M. Jonsson, Metabolism and community dynamics
within Nitella opaca(Charophyceae) beds in
Thingvallavatn, Oikos, 64, 241-256, 1992.
23) Kaufel, L., and I. Kaufel, Chara beds acting as nutrient
sinks in shallow lakes- a review, Aquatic Botany, 72,
249-260, 2002.
24) Kufel, L., and T. Ozimek, Can Chara control phosphorus
cycling in Lake Luknajo (Poland)? Hydrobiologia,
275/276, 277-283, 1994.
25) Krolikowska, J., Eutrophication process in a shallow,
macrophyte-dominated lake-species differentiation,
biomass and the distribution of submerged macrophytes in
Lake Luknajno(Poland), Hydrobiologia, 342/343, 411-416,
1997.
26) Lijklema, L., Nutrient dynamics in shallow lakes: effects
of changes in loading and role of sediment-water
interactions, hydrobiologia, 275/276, 335-348, 1994.
27) Pereya-Ramos, E., The ecological role of Characeae in the
lake littoral, Ekol. Pol., 29. 167-209, 1981.
28) Parsons, T.R., M. Takahashi, and B. Hargrave. Biological
Oceanographic Processes, 2nd Edition. Pergamon Press.
323 pp.
29) Sand-Jensen, K., Distribution and quantitative
development of aquatic macrophytes in relation to
sediment characteristics in oligotrophic Lake Kalgaard,
Denmark, Freshwater Biology, 9, 1-11, 1979.
30) Scheffer, M., Ecology of Shallow Lakes, Chapman & Hall,
London, 1998.
31) Schwarz, A.-M., and I. Hawes, Effects of changing water
clarity on characean biomass and species composition in a
large oligotrophic lake, Aquatic Botany, 56, 169-181,
1997.
32) Schwars, A.-M., M. de Winton, and I. Hawes,
Species-specific depth zonation in New Zealand
charophytes as a function of light availability, Aquatic
Botany, 72, 209-217, 2002.
33) Simons, J., M.Ohm, R.Daalder, P.Boers, W.Rip,
Restoration of Botshol (The Netherlans) by reduction of
external nutrient load: recovery of a characean community
dominated by Chara connivens. Hydrobioogia, 275/276,
243-253, 1994.
34) Squires, M.M. and L.F.W. Lesack, The relation between
sediment nutrient content and macrophyte biomass and
community structure along a water transparency gradient
among lakes of the Mackenzie Delta, Canadian Journal of
Fisheries & Aquatic Science, 60, 333-343, 2003.
35) Van den Berg, M.S., H.Coops, J.Simons, and A.de Keizer,
Competition between Chara aspera and Potamogeton
pectinatus as a function of temperature and light, Aquatic
Botany, 60, 241-250, 1998.
36) Van den Berg, M.S., H.Coops, J.Simons, and Jorn Pilton,
A comparative study of the use of inorganic carbon
resources by Chara aspera and Potamogeton pectinatus,
Aquatic Botany, 72, 219-233, 2002.
37) Vermeer, C.P., Escher, M., Portielje, R., and De Klein,
J.J.M., Nitrogent uptake and translocation by Chara,
Aquatic Botany, 76, 245-258, 2003.
38) Waisel, Y., and M. Agami, Are roots essential for normal
growth of Najas marina L.?, Proceedings of International
Symposium on Aquatic Macrophytes, Nijmegen, the
Netherlands, 287-291, 1983.
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