Cladophora (PROSEA)
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Introduction |
Cladophora Kütz.
- Protologue: Phycol. general.: 262 (1843).
- Family: Cladophoraceae
- Chromosome number: x= unknown; 2n= 12, 18, 24, 30
Major species and synonyms
Cladophora is considered to be taxonomically very difficult and it has not been studied in detail for South-East Asia. Names that have frequently been recorded are Cladophora albida (Nees) Kütz. (1843), C. pellucida (Huds.) Kütz. (1843), C. prolifera (Roth) Kütz. (1843), C. sericea (Huds.) Kütz. (1843), C. socialis Kütz. (1849) and C. vagabunda (L.) Hoek (1963). These names, however, must be regarded as uncertain and preliminary and cannot be used as reliable bases for additional data.
Vernacular names
- Philippines: lumot, lumot jusi.
Origin and geographic distribution
Approximately 150 species of Cladophora have been recorded worldwide. Many of these are marine algae, but several occur in freshwater. Cladophora is widespread over the whole globe, although it is virtually absent in polar waters.
Uses
In 1974 Cladophora was listed as one of the few marine algae cultivated in South-East Asia. This was in relation to milkfish cultivation, where members of Cladophora , together with Chaetomorpha spp. were cultivated and fertilized to be used as feed for fish. Young milkfish and milkfish larvae mainly feed on epiphytic microalgae ("lab-lab" in Filipino and "kelekap" in Indonesian) growing on and between the filamentous algae (see under Chaetomorpha spp.). Mature milkfish also eats the green filaments. Cladophora spp. are also used for animal feed and as a fertilizer. Some Cladophora spp. are known to have antibacterial and antiviral properties, whereas others have been used in Korea since the 6th century to make and strengthen paper. The algae are washed and dried until clean before they are pressed in paper processing, resulting in thin green stripes on the paper; this paper is mostly used for calligraphy.
Production and international trade
There are no data available yet on the commercial use of Cladophora, although these algae are successfully cultured in fish ponds in the Philippines and Indonesia.
Properties
Cladophora cell walls have a high cellulose content (up to 70%) and the cells contain almost 25% protein (dry weight basis). Some Cladophora spp. produce acid mucilages, which are documented as containing 20% sulphuric acid and a galactan sulphate known as cladorphorin. This compound contains acid-resistant polyuronide groups in the molecule and it is difficult to hydrolyse. Hydrolysis of Cladophora biomass yields arabinose, galactose, xylose, rhamnose and glucose; these sugars are present in relative molecular proportions of approximately 16:12:4:2:1. Bromine and glycine betaine are also found in Cladophora. C. rupestris (L.) Kütz., a species not yet recorded for South-East Asia, is known to contain acrylic acid which shows antibacterial activity.
Description
- Plants filamentous, sparingly to repeatedly branched, attached by rhizoidal extensions from the lower cells, the filaments spreading over the substratum and often giving rise to new erect shoots; growth primarily apical; chromatophores reticulate, with many pyrenoids or separate disks, and numerous nuclei in each cell.
- Life cycle haplontic or diplo-haplontic and isomorphic.
Growth and development
Both asexual and sexual reproduction take place in Cladophora. Asexual zoospores arise within the vegetative cells in large numbers, and escape through a round orifice; these swarmers have four cilia. The sexual gametes arise in the same way; they have two cilia and show a red spot. The gametes conjugate in pairs (isogamy), and form a zygote which at once begins to germinate into a vegetative thallus similar to the mother plant. In some Cladophora spp. a chain of cells, endowed with thicker walls and denser granular contents, separates off and becomes a cyst which, after a period of rest, grows out into a new frond.
Other botanical information
Recent data have made clear that Cladophora is of paraphyletic nature and cannot be regarded as a natural genus. Nobody, however, has yet proposed a more satisfactory classification.
Ecology
Cladophora spp. mainly occur attached to rocky substrates, but a few can form extensive, free-floating masses in more or less stagnant, eutrophic waters, such as coastal lagoons or freshwater ponds. Usually Cladophora spp. occur in shallow waters, but some have been dredged from depths of up to 55 m, whereas a few of them are capable of surviving considerable fluctuations in salinity. Annual as well as perennial Cladophora spp. occur.
Propagation and planting
Tufts or mats of Cladophora spp., mixed with Chaetomorpha spp. and many epiphytic and epipsammic microalgae are transferred to new fish ponds to promote growth of milkfish feed.
Phycoculture
When necessary, commercial fertilizers are added to the tufts and mats of Cladophora in the fish ponds.
Harvesting
Cladophora algae in fish ponds are mainly harvested by the fish. Thick mats can be thinned and the surplus material can be used as feed for animals or as a fertilizer.
Handling after harvest
The surplus material of Cladophora can be used fresh as well as air-dried and cut into pieces.
Prospects
Cladophora will be a lasting component of the natural algal mats in traditional fish ponds used for milkfish culture.
Literature
- Ballantine, D.L., Gerwick, W.H., Velez, S.M., Alexander, E. & Guevara, P., 1987. Antibiotic activity of lipid-soluble extracts from Caribbean marine algae. Hydrobiologia 151/152: 463-469.
- Benitez, L.V., 1984. Milkfish nutrition. In: Juario, J.V., Ferraris, R.P. & Benitez, L.V. (Editors): Advances in milkfish biology and culture. Island Publishing House Inc., Metro Manila, The Philippines. pp. 133-143.
- Blunden, G., Gordon, S.M., McLean, W.F.H. & Guiry, M.D., 1982. The distribution of possible taxonomic significance of quaternary ammonium and other Dragendoff-positive compounds in some genera of marine algae. Botanica Marina 24: 563-567.
- Van den Hoek, C., Stam, W.T. & Olsen, J.L., 1992. The Chlorophyta: systematics and phylogeny. In: Stabenau, H. (Editor): Phylogenetic changes in peroxisomes of algae. Phylogeny of Plant Peroxisomes. University of Oldenburg, Germany. pp. 330-364.
Sources of illustration
Bakker, F.T., 1995. Time spans and spacers: molecular phylogenetic explorations in the Cladophora complex (Chlorophyta) from the perspective of rDNA gene and spacer sequences. Thesis. Rijksuniversiteit Groningen, Groningen, The Netherlands. Fig. 1.1, p. 4 (C. albida, C. sericea); van den Hoek, C., Mann, D.G. & Jahns, H.M., 1995. Algae. An introduction to phycology. Cambridge University Press, Cambridge, United Kingdom. Fig. 23.5, p. 414 (C. vagabunda). Redrawn and adapted by P. Verheij-Hayes.
Authors
- P.Y. van Aalderen-Zen
