Phycology جلبک شناسی

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TAXONOMY/SPECIES PLANTS (COMPRISING FLOWERING PLANTS, ALGAE, FUNGI, LICHENS)

TAXONOMY/SPECIES

PLANTS (COMPRISING FLOWERING PLANTS, ALGAE, FUNGI, LICHENS)

 

 

compiled by J.J. Bolton

 

 

 

Introduction

The photosynthetic organisms in the sea are from a wide variety of groups. The group most familiar on land, the flowering plants, are important only in certain coastal fringe environments (particularly estuaries), whereas rocky seashores and the sea itself have photosynthetic organisms which come from a variety of different groups. In the past most of the latter have been lumped together as ‘algae'. The ‘green algae' (Chlorophyta) include the green seaweeds and a wide variety of smaller algae, and are true green plants, related to the flowering plants. Other algae comprise at least twelve ‘Divisions' (equivalent to zoological Phyla). The broad term ‘algae' has also traditionally included the ‘blue-green algae', which are true bacteria (the Cyanobacteria), and are important in many marine environments. The fungi, though not photosynthetic, have often in the past between treated as ‘plants', and of course this is even more confused by the lichens, which are a symbiosis of an alga and a fungus. Molecular phylogenetic studies are revealing that relationships between these organisms are much more complicated than first thought, and that there are many more groups of living things than just ‘plants' and ‘animals'. For example one Division, the Heterokontophyta, now comprises a remarkable diversity of organisms, including brown algae (e.g. Ecklonia) and diatoms as well as a group that was traditionally in the fungi (the Oomycetes). The organisms discussed below are thus grouped primarily ecologically, rather than phylogenetically.

 

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Flowering Plants

by J.J. Bolton & R.A. Lubke

 

Generally, the expertise to identify flowering plants is available in a number of centres (e.g. National Botanical Institute (NBI) and various herbaria), and literature on and well-curated collections of flowering plants are also readily accessible within the country. Many ecological studies have been carried out in marine systems where flowering plants occur - generally estuaries and lagoons with mangroves, salt marshes or seagrass beds (Lubke et al., 1997) - and identification of specimens has not proved a problem.

 

A large body of ecological and ecophysiological work has been carried out on South African mangrove systems, particularly at the University of Durban-Westville (Steinke, Naidoo and colleagues). Mepham & Mepham (1985) published locally a list of the flowering plants occurring in mangrove systems in the Indo-West Pacific. Detailed descriptions of main mangrove trees are in preparation for the series of Flowering Plants of Southern Africa (H.F. Glen, pers. comm.). South African saltmarshes are rather small in area, but interesting and important systems. They were studied in detail by O'Callaghan (1994), who also carried out studies to improve identification, e.g. of the Salicornieae (O'Callaghan, 1992).

 

Seagrasses are not very diverse in most of South Africa, with Zostera capensis being the dominant species in the Cape Provinces. Diversity increases into the tropics, with three other species in estuaries and on rocky shores in KwaZulu-Natal. Salomao Bandeira of the Universidade Eduardo Mondlane in Maputo is currently working on the autecology of seagrasses of the Mozambique coast. He is familiar with their taxonomy and has indicated the need for more work on these taxa.

 

 

 

Algae

 

Perhaps the main problem facing algal taxonomy in South Africa is that there is no government agency which will accept responsibility for it. This was traditionally the responsibility of the Botanical Research Institute (now the National Botanical Institute, NBI) who were the original employers of the “government seaweed biologist” (then R.H. Simons before his transfer to Marine and Coastal Management (MCM)). The Seaweed Unit of MCM does not currently have taxonomy as part of their brief. The NBI indicated to the Phycological Society of Southern Africa in 1997 that “it is unlikely that the NBI would taken on a national responsibility for algal taxonomy”. For those who intend training (or funding the training of) algal taxonomists it is obviously problematic that there is no national agency which will take responsibility for algal taxonomy.

 

 

Macroalgae

by J.J. Bolton, R.N. Pienaar & S.D. Sym

 

Status of taxonomy and levels of endemism?

Most of the taxonomic descriptions of marine macroalgae (seaweeds) are from the 19th century, and many groups have had little or no subsequent taxonomic revision. Since 1980, significant studies have added greatly to our knowledge of the taxonomy of the seaweeds of the South African west coast (west of Cape Agulhas; see Stegenga et al., 1997) and the red algae of KwaZulu-Natal (numerous papers on specific groups by R. Norris). Species are being regularly sent to overseas workers to form part of systematic studies on specific groups - particularly using molecular techniques (e.g. studies by Hommers and and colleagues). A large body of work is being carried out by Y. Chamberlain (University of Portsmouth, U.K.) and D. Keats (University of the Western Cape) and colleagues on the non-geniculate (coralline) red algae. These are ecologically extremely important in shallow waters, and many new species have been recently described.

 

Apart from D. Keats' work on crustose corallines and a few contributions by R.H. Simons (now retired), R.J. Anderson and J.J. Bolton, almost all taxonomic work has been done by visitors from overseas (e.g. Norris, Stegenga, Chamberlain) who have now left. The seaweeds of the west coast are rather well documented (Stegenga et al., 1997), and those of KwaZulu-Natal, particularly the red algae, are reasonably documented (although the information is in algal journals, and only accessible to the expert). The seaweeds of the south coast (Agulhas marine province) have had little recent taxonomic study, apart from a few contributions by Herre Stegenga. The roughly 800 recorded species of South Africa seaweeds is a rich flora by world standards, with high levels of endemism (Bolton & Anderson, 1997). For example, over 50% of the west coast species in Stegenga et al. (1997) are endemic to temperate southern Africa. An NRF project currently running (principal investigator J.J.B.) is summarising our current knowledge of the seaweed flora, including analyses of distribution and endemism. There are still many new finds to be made, particularly in the subtidal regions of the Eastern Cape and KwaZulu-Natal.

 

Seaweed collections

There are good collections of seaweeds at the Universities of Cape Town (UCT) and Natal (Pietermaritzburg) and the Pocock collection in Grahamstown. Although these are curated technically, there is no real regular taxonomic input at any of these, due to the lack of a seaweed taxonomist working on them, and the future of the Pocock collections in the Albany Museum is not certain.

 

Status of the tools of systematics and taxonomy

The tools of taxonomy are available in South Africa, and there is a movement towards taxonomic studies using molecular techniques. These studies have begun on corallines (under D. Keats at University of the Western Cape) and on endophytic algae and the red algal genus Porphyra jointly supervised by J.J.B. and Vernon Coyne at UCT. These techniques are, however, expensive, and the NRF is currently likely to be the only sponsor for this sort of research.

 

 

Status of outreach in seaweed taxonomy

The ability of the marine biologist to identify seaweeds on the west coast has taken a major step forward with the publication of Stegenga et al. (1997). Proper identification of even some of the more common seaweeds in the Eastern Cape and KwaZulu-Natal still requires an expert with access to the primary literature. Marine biologists in these regions still have only illustrations of larger common species in Branch et al. (1994) or similar publications to identify seaweeds. While useful, these have no scientific detail to confirm identification, and contain less than 25% of the seaweed species present.

 

Main problems

The main problems in seaweed taxonomy are thus:

·           No government body taking responsibility for algae.

·           Little recent work on the south coast or the brown and green algae of the east coast.

·           Unavailability of existing taxonomic information on the south and KwaZulu-Natal coasts to marine biologists.

·           Need for detailed studies (including those using molecular techniques) on taxa of particular economic and ecological importance.

 

 

Microalgae

by R.N. Pienaar and S.D. Sym

 

General comments

The status of our knowledge on the diversity of marine and estuarine microalgae, on the whole, is poor. This is due to the fact that there are very few laboratories in South Africa that are doing research on microalgae. This is probably because of the very specialised techniques that are needed to identify microalgae, coupled with the fact that there is really only one laboratory in the country that is specialising in microalgal research (viz. R.N. Pienaar's laboratory at the University of the Witwatersrand).

 

There are a number of algal divisions that are well represented in the marine and estuarine environment and about which we know very little. The following algal divisions are known to occur in our marine and estuarine environments. We have also attempted to indicate the status of our knowledge for each division.

 

Division

Status of Knowledge

Cyanophyta

Reasonably good since S. Silva joined R.N. Pienaar's research group. This work has concentrated primarily on the benthic members of the group and very little on the planktonic forms. The work S. Silva has done is exclusively inshore and tidal pool flora

Chlorophyta Class Chlorophyceae

Poor

                      Class Prasinophycea

Reasonable to good

Chrysophyta

Poor except for the very common forms

Prymnesiophyta

Reasonable with respect to the non-coccolith bearing forms. Poor when it comes to the coccolith-bearing forms

Raphidophyta

Poor

Eustigmatophyta

Poor

Cryptophyta

Reasonable to poor

Dinophyta

Reasonable with respect to inshore and tidal pool species and for some of the heavily armoured forms. For the colourless and un-armoured forms our knowledge is very poor. Marine and Coastal Management and to a lesser degree the University of Port Elizabeth have being doing some work on marine inshore dinoflagellates

Bacillariophyta

Marine inshore and tidal pool forms poor to reasonable; Estuarine planktonic forms poor

 

 

Status of expert knowledge in microalgae

There is at the moment a dearth of scientists who have developed any expertise in the taxonomy of marine and estuarine microalgae. The main laboratory that has been working on microalgae is that of R.N.Pienaar. This laboratory has had a number of researchers working on specialised groups of marine inshore and tidal pool representatives of microalgae.

 

These include:     S. Silva           Postdoctoral Fellow working on the Cyanophyta.

                          T. Horiguchi   Visiting postdoctoral fellow who worked on tidal pool dinoflagellates.

                          S.D. Sym       Current member of staff specialising in the Prasinophyceae.

                         R.N. Pienaar   Currently specialising in the Prymnesiophyta and also working on the

           Dinophyta, Cryptophyta and Chrysophyta.

                          I. Inouye         Visiting postdoctoral Fellow who worked on Prymnesiophyta.

 

The Universities of Port Elizabeth and Durban-Westville are currently involved in work on the Bacillariophyta (diatoms) but still have to build up a good knowledge base on diatom taxonomy. This is an important group of microalgae and there should be a laboratory in South Africa that specializes in this group.

 

Facilities for studying microalgae

Facilities for the study of microalgae are good with respect to R.N. Pienaar's laboratory. Good light microscope facilities are required, as well as a well-equipped electron microscope unit and good culture facilities to maintain culture collections.

 

Outreach in microalgal systematics

There is a need to once again commence offering specialist courses in microalgal systematics and the techniques used to study microalgae. Courses were offered by R.N. Pienaar - one on techniques used to study microalgae and a second on microalgal systematics. These were run under the umbrella of the Phycological Society of Southern Africa. These should possibly be run again and elaborated upon based on the status of our current knowledge.

 

Status of reference collections

These are virtually non-existent. The University of the Witwatersrand has a microalgal reference culture collection but it is by no means extensive. It currently houses about 150 isolates. It takes a great deal of time and money to maintain and curate a good collection. Funding for a research assistant to undertake this work has not been forthcoming. The collection is frequently called upon to provide cultures to organizations doing work in the mariculture field, research organizations and tertiary institutions requiring material for teaching purposes.

 

We are striving to develop a reference catalogue of the organisms that we have identified, isolated, etc., which could eventually be used by new workers in the field.

 

 

Fungi

by T. Steinke

 

Kohlmeyer & Kohlmeyer (1979) state that “information on the geographical distribution of marine fungi is missing particularly in the Southern Hemisphere, in the Arctic, Antarctic and Indian Oceans, and in the eastern Mediterranean and Black Sea”. The author appears to be the only local person researching marine and estuarine fungi. This work concerns the estuarine fungi associated with the degradation of mangrove leaf and stem litter, and the marine fungi of sandy beaches and rocky shores (Steinke & Gareth-Jones, 1993). The mangrove project covers estuaries only where mangroves occur, i.e. from East London northwards, the sandy beach survey stretches from the Kosi system in northern KwaZulu Natal to Henties Bay in Namibia, and the rocky shore survey extends from Mission Rocks (St. Lucia) to Langebaan. The latter project is restricted to fungi associated with intertidal driftwood. It is hoped that this work will be published in the next year or two. There are serious gaps in that no investigations have been carried out in estuaries where mangroves do not occur, even along the east coast substrates other than mangroves need to be investigated, and more collections of rocky shore fungi are needed from East London northwards. Little information is available on marine fungi associated with marine algae and marine animals.

 

Fungi have been shown in recent years to play a significant degradative role in marine and estuarine environments. Unfortunately in this country, and also elsewhere, marine fungi seem to have been almost overlooked in evaluating food chains. Knowledge of the occurrence and distribution of fungi will contribute towards a greater understanding of the role of these organisms in different marine ecosystems.

 

Extensive taxonomic surveys of marine fungi have been conducted in Europe, North America and the Far East. There are a number of very competent taxonomists working in these areas. Although most of our marine fungi are common to these areas, clearly there are some new species that require investigation. Local researchers investigating our marine fungi will require basic mycological laboratory research facilities and access to electron microscopes. Most importantly, to assist in building up their expertise, local researchers must have the opportunity to make contact with overseas workers in their field. It is essential that a reference collection should be established as, apart from T. Steinke's own collection, little seems to be available. Attention must be drawn to the fact that in recent years isolates of marine fungi have proved a new source of commercially important fungus metabolites, which could serve as an additional motive for their investigation and possibly a source of funds for taxonomic studies.

 

 

Lichens

by J.J. Bolton

 

The taxonomy of lichens is currently a gap in South African taxonomy in general, with no active resident lichen taxonomist. Work has been done in the past, and there are local collections, and it is likely that names exist for species in the spray (maritime) zone above the intertidal, but for a reliable identification an overseas taxonomist would have to be approached.

 

Intertidal lichens are in need of study. They are not uncommon on rocky shore mollusc shells on the west coast, with a species of Verrucaria being fairly common as black crusts with rounded edges on whelks and limpets in the mid-intertidal, and two species of Pyrenocollema occurring as whitish patches on limpets (A. Fletcher and Y.M. Chamberlain, pers. comm.). These species remain undescribed.

 

 

REFERENCES

 

Bolton, J.J. & Anderson, R.J. (1997). Marine Vegetation. In: Vegetation of Southern Africa. Cowling, R.M., Richardson, D.M. & Pierce, S.M. (eds). Cambridge University Press, Cape Town.

 

Branch, G.M., Griffiths, C.L., Branch, M.L. & Beckley, L.E. (1994). Two Oceans: A Guide to the marine life of southern Africa. David Philip; Cape Town.

 

Kohlmeyer, J. & Kohlmeyer, E. (1979). Marine mycology: The higher fungi. Academic Press, New York.

 

Lubke, R.A., Avis, A.M., Steinke, T.D. & Boucher, C. (1997). Coastal vegetation. In: Vegetation of Southern Africa. Cowling, R.M., Richardson, D.M. & Pierce, S.M.(eds). Cambridge University Press, Cape Town.

 

Mepham, R.H. & Mepham, J.S. (1985). The flora of tidal forests - a rationalization of the term ‘mangrove'. S. Afr. J. Bot., 51: 77-99.

 

O'Callaghan, M. (1992). The ecology and identification of the southern African Salicornieae (Chenopodiaceae). S. Afr. J. Bot., 58: 430-439.

 

O'Callaghan, M. (1994). Salt marshes of the Cape (South Africa): Vegetation dynamics and interactions. PhD. thesis, University of Stellenbosch, South Africa.

 

Stegenga, H., Bolton, J.J. & Anderson, R.J. (1997). Seaweeds of the South African west coast. Contr. Bol. Herb., 18: 655pp.

 

Steinke, T.D. & Gareth-Jones, E.B. (1993). Marine and mangrove fungi from the Indian Ocean coast of South Africa. S. Afr. J. Bot., 59: 385-390.

 

Marine Biodiversity Status Report, March 2000, Edited by B.D. Durham & J.C. Pauw

  
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