| no worries David... with the hearty water change schedule you are doing, it is likely a big help here... if you added ozone to the system, I'd have few if any worries about the exudations. Please stay strong with those water changes though.. it is crucial IMO. If you do a keyword search combinations for "algae" "allelopathy" and with "scleractinia" on http://scholar.google.com you will find some very interesting hits. Plus... below are some references to follow that Eric shared with me some years ago: 1. Anjaneyulu ASR, Prakash CVS, Raju KVS, Mallavadhani UV. 1992. Isolation of new aromatic derivatives from a marine algal species Caulerpa racemosa. J Natural Products 55(4): 496-499. summary: produce acetylenic sequiterpenoids, triterpenoids, nitrogenous compounds in addition to the red pigment, caulerpin. Along with caulerpin is a colorless toxic substance; a mixture of N-acyl sphingosines and sitosterol. 5 new propane dimer compounds found - uncommon aromatic derivatives not usually found in marine algae. 2. Faulkner, DJ. 1988. Marine Natural Products. Natural Products Reports. 615-616 University of California, San Diego, Scripps Institute of Oceanography, La Jolla, CA 92093 USA summary: caulerpin and its corresponding diacid show activity similar to indoleacetic acid - six new sesquiterpenes isolated from C. ashmeadii and found toxic to damselfish and showed antimicrobial activity. 3. Hashimoto Y. and Fusetani N. 1972. Screening of the toxic algae on coral reefs. Proceedings of the International Seaweed Symposium 7: 569-572. summary: caulerpicin and caulerpin, toxic substances of the genus Caulerpa, accumulate in the food chain - found in gastropods, surgeonfish and soft corals but found comapratively non-toxic to mammals. 4. McConnell Oliver J., Hughes Patricia A.,, Targett Nancy M, Daley Joyce. 1982. Effects of secondary metabolites from marine algae on feeding by the sea urchin, Lytechinus variegatus. J Chemical Ecology 8(12): 1437-1453. summary: C. prolifera: caulerpenyne (oxygenated sesquiterpene) C. racemosa and C. ahmaedii contained caulerpin caulerpenyne and extract from C. prolifera redeces urchin herbivory by 50%,singificantly - even at 0.4% of fresh weight and 0.1% extract although very high levels of caulerpin in other species, feeding not detreed in the urchin (believed for this urchin to be a chemical attractant as it is toxic to other animals) 5. Meinesz, Alexandre and Simberloff, Daniel. 1999. Killer Algae. University of Chicago Press, Chicago. pp. 295-304. summary: mainly concerns the highly problematic C. taxifolia (I'm sure you can get plenty of information on this puppy!). Caulerpales have specific anatomy of no internal cell walls and therefore no specialized cells. When cut a milsky "sap" flows out with carbohydrte plug formed quickly. Liquid occupies entire cavity of the algae. Compsoed of three elements: stolon, fronds and rhizoids. Stolon can be over 2m in length andis branched. Greek caulos meaning stem and erpo meaning creep. rhizoids penetrate every surface and adapt to bottom texture (long in sand or mud, short in rock) axes can grwo up to 2cm/day, elongteing at one end and dying at the other, no part of thallus lives more than a year. Leads to rapdily dense colonies that then compeete with plants and sessile animals. up to 8200 frons/square meter. When axes die, colony becomes fragmented. Each fragment, so long as it contains a nucleus, can form a new alga and all fragments likely contain numerous nuclei. 1cm fragment can produce 3m colony in 6 months. Reproduction follows an unusal strategy - several days each year, nucleus joins with chloroplast, surrounds itself with a membrane and transforms into male or female gamte, expelled through small orfiices and the plant dies (no cell walls, so everythingis lost). Plants are monecious (both sexxes in same plant) and gametes are about 5 micrometeres- passage from egg to palnt takes 3-6 months - puts pretty much everything into sexual reproduction and is designed that way. Caulerpa includes nearly 100 species - most of those we keep are both tropical and temperate (prolifera, taxifolia, racemosa, mexicana, crassifolia) 6. Littler, Diane Scullion and Littler, Mark Masterson. 2000. Caribbean Reef Plants. OffShore Graphics Inc, Washington, D.C. pp. 356-380 summary: Caulerpa racemosa overtops and kills reef-building corals. textbook (didn’t get the reference information) Introduction to the Algae pp. 229-230 "the production of a deadly posion by species of Caulerpa, referred to as caulerpicin... is known to enter marine food chains. 7. Paul, Valerie J., and Fenical, William. 1986. Chemical defense in tropical green algae, order Caulerpales. Marine Ecology Progress Series 34: 157-169 summary - ok, this is the mother lode.... 40 species of Caulerpa chemically investigated. "virtually all produce toxic seconary metabolites of a unique and unprecedented class. These metabolites are generally linear terpenoids, but unsual structural features such as aldehydes and bis-enol acetate functional groups makes these compounds unqiue. the compounds are toxic or deterrent towards microorganisms,s ea urchin larvae, and herbivorous fishes, and when incorporated into diets at naturally occurring concentrations casue mortality in juvenile conch. Concentrations of bioactive metabolites were found to show liittle variation in different plant parts such as baldes, stipes, and holdfasts." Young growing tips and reproductive structures contained higher concentartions than mature plant tissues on dry weight basis (i.e. youprune it, you get more toxins). Qualitative and quantitative variation observed in different populations of the same species. Highest herbivory = greatest concentrations. all of the metabolites showed antimicrobial acitivity several toxic to sea urchin sperm at very low concentrations all compounds toxic to sea urchin larvae within 24 hours and several active at very low (1 x 10-7M) concentration majority were toxic to fish within 1 hour at concentrations as low as 5micrograms/ml - compounds not direectly toxic still showed detrimental effects (sedated beahvior, discoloration, increased respiration) all showed significant fish feeding deterrence 50% of conchs died within 6 days feeding on Caulerpa caulerpenyne was 0.35% dry weight (very high levels)"Of the many diverse metabolites that we and others have isolated from a wider spectrum of marine plnts, few show the potent activities of these green algal metabolites in these bisassays. The compounds inhibit the growth of microorganisms, development of fertilzied urchin eggs, and they are toxic to larval and adult stages of potential herbivores." Caulerpenyne isolated in varying concentrations from C. taxifolia, sertularoides, racemosa, mexicana, cuppressoides, prolifera, verticallata, paspaloides, and lanuginosa. and shows strong toxic and feeding deterrent properties - much of the biological activity of Caulerpa owed tothis compound. Parrotfish show low survivability when fed Caulerpales- with mortalities attributed to Caulerpa toxins.
.Anthony Calfo
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