Marine and Freshwater Algae

Marine and Freshwater Algae
		by *Richard L. Moe* University of California
Algae are an extremely diverse group of photosynthetic organisms that range from single-celled organisms to complex thalli (e.g., kelps). Benthic algae live attached to the bottom of a water body or to living or nonliving objects on the bottom. Planktonic algae live free-floating in the ocean and in the largest to smallest lakes and streams. Algae also occur in such varied places as the surface layers of soils and porous rocks, on the bark and leaves of trees, in snow, hot springs, and in symbiotic association with fungi to form lichens.
These organisms are important as primary producers (representing the base of the food chain or pyramid), in contributing to the fertility of soil, in providing substrate for other organisms, and in defining aquatic environments such as kelp beds and algal reefs.
The toxicity of certain marine unicellular algae can limit coastal marine fisheries (e.g., dinoflagellates in red tide). In fresh water, blooms tied to nutrient enrichment are often a major nuisance. A few species of macrophytic algae (large enough to be seen by the naked eye) are harvested from the wild for food and industrial purposes.
Knowledge of the algae of the United States is not uniform across various groups or environments. Some modern regional floras, or lists of plants (e.g., California, southeastern coast, gulf coast), are available for marine benthic macroscopic algae (Dawes 1974; Abbott and Hollenberg 1976; Schneider and Searles 1991), of which there are approximately 900 species on the Pacific coast and fewer on the Atlantic and gulf coasts (approximately 450 for the northern Atlantic coast, 350 for the southeastern Atlantic coast, and 300 for the gulf coast). Local floras are available for many places. Few species are shared between the Atlantic and Pacific coasts. Information about marine microalgae is less accessible.
Local and regional floras are available for some groups of freshwater algae (e.g., Hoshaw and McCourt 1988; Dillard 1989; Johansen 1993), but information is absent or has not been compiled for much of the country. Because no attempt has been made to produce a national flora of freshwater algae in this century, it is not possible to estimate the number of such species. Many groups of algae are cosmopolitan, however, and European monographs and floras can be useful.
In general, distribution, status, and trends of algae, even of conspicuous marine algae, are not well established. Floras usually provide ranges, but distribution of many species may be discontinuous, with various causes for the discontinuity. Filling the gaps (or confirming the discontinuities) will require considerable effort.
Although nationwide data on status and trends of North American algal populations are not readily available, scientists do know that a great deal of formerly aquatic habitat has become unavailable for algae because of landfill, reclamation, and water diversion. In addition, other habitat has been altered through farming and municipal and industrial waste discharge. In the case of reservoirs, however, one kind of aquatic habitat has been replaced by another.
Long-term information about phytoplankton is available for the Great Lakes; this information has allowed documentation of water-quality improvement in Lake Erie and analysis of the effect of the invasion of the zebra mussel (Dreissena polymorpha; Makarewicz 1993; Nicholls 1993). Much limnological information is available for individual water bodies or catchment basins (e.g., Brock 1985 for Lake Mendota in Wisconsin), but reconciling the different methods used when comparing separate studies is a challenge.
Interpretation of marine baseline and trend data is complicated by differences in communities over time and space (Foster et al. 1988). An example of the utility of marine baseline studies is the census of algae along the coast near Los Angeles (Dawson 1959) that showed how sewage discharge reduced algal diversity. Subsequent resurveys (Widdowson 1971) demonstrated some improvement after stricter environmental regulations were enacted. Long-term studies are available for giant kelp (Macrocystis pyrifera), the economically important component of southern California kelp beds. North (1971) and Foster and Schiel (1985) documented the decline of kelp beds after sewage was discharged into the ocean. They also discussed the partly successful attempts at remediation, which involved transplantation and predator control and which led to an appreciation of the complexity of organismal interactions in kelp beds.
Achieving a uniform estimate of the status of algae in North America will take considerable original observation and collection. Further-more, different research approaches will be necessary for freshwater versus marine algae and for macrophytic algae versus microphytic algae. To determine status and trends of marine macroalgae, published literature must be compiled and analyzed. In addition, unpublished information should be obtained from herbaria and from private collections in the form of specimens, labels, and collectors' notebooks, illustrations, and checklists.
This process has been followed for west coast algae in a project by T. DeCew, the results of which are available at the Herbarium of the University of California. This project condenses the 100-year record of west coast phycology (study of algae) by using a literature review, compilation of data from specimens at west coast herbaria, and original observations. For each species a tabular representation of geographic and hydrographic range is provided. Presence or absence in different precincts along the coast and details of phenology (relations between climate and periodic biological phenomena), such as reproductive state throughout the year, are indicated. The study gives ecological information such as requirements for substrate and exposure to waves as well as the presence of epiphytes and parasites. In addition, illustrations and references to pertinent taxonomic, chemical, ecological, genetic, and physiological literature are given.
If this kind of project is done on a national scale, workers must have the necessary taxonomic training and herbarium resources must be preserved. About 100 American scientists have algal taxonomy as a principal area of interest (Anonymous 1992). Modern molecular taxonomic methods aid in the study of some groups of algae, but to progress toward a national inventory, traditional taxonomic methods must be supported.
		For further information: Richard L. Moe University of California University Herbarium Berkeley, CA 94720

References
Abbott, I.A., and G.J. Hollenberg. 1976. Marine algae of California. Stanford University Press, CA. 827 pp. Anonymous. 1992. 1992 Membership Directory and Bylaws [of the Phycological Society of America]. Journal of Phycology (4, supplement). Brock, T.D. 1985. A eutrophic lake: Lake Mendota, Wisconsin. Springer-Verlag, New York. 308 pp. Dawes, C.J. 1974. Marine algae of the west coast of Florida. University of Miami Press, Coral Gables, FL. 201 pp. Dawson, E.Y. 1959. A preliminary report on the marine benthic flora of southern California mainland shelf. Pages 169-264 in Oceanographic survey of the Continental Shelf area of southern California. California State Water Pollution Control Board Publ. 20. Dillard, G.E. 1989. Freshwater algae of the southeastern United States. Part 1. Chlorophyceae: Volvocales, Tetrasporales and Chlorococcales. Bibliotheca Phycologica 81. 202 pp. Foster, M.S., A.P. De Vogelaere, C. Harrold, J.S. Pearse, and A.B. Thum. 1988. Causes of spatial and temporal patterns in rocky intertidal communities of central and northern California. Memoirs of the California Academy of Sciences 9. 45 pp.	Foster, M.S., and D.R. Schiel. 1985. The ecology of giant kelp forests in California: a community profile. U.S. Fish and Wildlife Service Biological Rep. 85 (7.2). 152 pp. Hoshaw, R.W., and R.M. McCourt. 1988. The Zygnemataceae (Chlorophyta): a twenty-year update of research. Phycologia 27:511-548. Johansen, J.R. 1993. Cryptogamic crusts of semiarid and arid lands of North America. Journal of Phycology 29:140-147. Makarewicz, J.C. 1993. Phytoplankton biomass and species composition in Lake Erie, 1970 to 1987. Journal of Great Lakes Res. 19:258-274. Nicholls, K.H. 1993. Recent changes in Lake Erie (North Shore) phytoplankton: cumulative impacts of phosphorous loading reductions and the zebra mussel introduction. Journal of Great Lakes Res. 19:637-647. North, W.J., editor. 1971. The biology of giant kelp beds (Macrocystis) in California. Beihefte zur Nova Hedwigia 31. 600 pp. Schneider, C.W., and R.B. Searles. 1991. Seaweeds of the southeastern United States: Cape Hatteras to Cape Canaveral. Duke University Press, Durham, NC. 553 pp. Widdowson, T.B. 1971. Changes in the intertidal algal flora of the Los Angeles area since the survey by E. Yale Dawson in 1957-1959. Bull. of the Southern California Academy of Sciences 70:2-16.

References

Abbott, I.A., and G.J. Hollenberg. 1976. Marine algae of California. Stanford University Press, CA. 827 pp.

Anonymous. 1992. 1992 Membership Directory and Bylaws [of the Phycological Society of America]. Journal of Phycology (4, supplement).

Brock, T.D. 1985. A eutrophic lake: Lake Mendota, Wisconsin. Springer-Verlag, New York. 308 pp.

Dawes, C.J. 1974. Marine algae of the west coast of Florida. University of Miami Press, Coral Gables, FL. 201 pp.

Dawson, E.Y. 1959. A preliminary report on the marine benthic flora of southern California mainland shelf. Pages 169-264 in Oceanographic survey of the Continental Shelf area of southern California. California State Water Pollution Control Board Publ. 20.

Dillard, G.E. 1989. Freshwater algae of the southeastern United States. Part 1. Chlorophyceae: Volvocales, Tetrasporales and Chlorococcales. Bibliotheca Phycologica 81. 202 pp.

Foster, M.S., A.P. De Vogelaere, C. Harrold, J.S. Pearse, and A.B. Thum. 1988. Causes of spatial and temporal patterns in rocky intertidal communities of central and northern California. Memoirs of the California Academy of Sciences 9. 45 pp.

Foster, M.S., and D.R. Schiel. 1985. The ecology of giant kelp forests in California: a community profile. U.S. Fish and Wildlife Service Biological Rep. 85 (7.2). 152 pp.

Hoshaw, R.W., and R.M. McCourt. 1988. The Zygnemataceae (Chlorophyta): a twenty-year update of research. Phycologia 27:511-548.

Johansen, J.R. 1993. Cryptogamic crusts of semiarid and arid lands of North America. Journal of Phycology 29:140-147.

Makarewicz, J.C. 1993. Phytoplankton biomass and species composition in Lake Erie, 1970 to 1987. Journal of Great Lakes Res. 19:258-274.

Nicholls, K.H. 1993. Recent changes in Lake Erie (North Shore) phytoplankton: cumulative impacts of phosphorous loading reductions and the zebra mussel introduction. Journal of Great Lakes Res. 19:637-647.

North, W.J., editor. 1971. The biology of giant kelp beds (Macrocystis) in California. Beihefte zur Nova Hedwigia 31. 600 pp.

Schneider, C.W., and R.B. Searles. 1991. Seaweeds of the southeastern United States: Cape Hatteras to Cape Canaveral. Duke University Press, Durham, NC. 553 pp.

Widdowson, T.B. 1971. Changes in the intertidal algal flora of the Los Angeles area since the survey by E. Yale Dawson in 1957-1959. Bull. of the Southern California Academy of Sciences 70:2-16.