Gerald E. Walsh

MANGROVES: A REVIEW1

“The beaches on that coast I had come to visit are treacherous and sandy and the tides are always shifting things about among the mangrove roots…A world like that is not really natural…Parts of it are neither land nor sea and so everything is moving from one element to another, wearing uneasily the queer transitional bodies that life adopts in such places. Fish, some of them, come out and breathe air and sit about watching you. Plants take to eating insects, mammals go back to the water and grow elongate like fish, crabs climb trees. Nothing stays put where it began because everything is constantly climbing in, or climbing out, of its unstable environment.”

Toxicity of textile mill effluents to freshwater and estuarine algae, crustaceans and fishes☆

Abstract The toxicity of secondary waste effluents from textile manufacturing plants was determined with freshwater (Selenastrum capricornutum, Daphnia pulex, Pimephales promelus) and estuarine Skeletonema costatum2, Palaemonetes pugio, Cyprinodon variegatus) organisms. Daphnia pulex was generally the most sensitive animal, but no animal responded to all wastes. Growth of the algae S. capricornutum and S. costatum was affected by all wastes, through either inhibition or stimulation. Some wastes were stimulatory to S. costatum at low concentrations ( 50%). The concentration of waste that stimulated growth of S. costatum by 20% compared with controls (SC 20 ) was calculated and used with EC 50 values for the survival of D. pulex to estimate the potential impact of the wastes in relation to volume of discharge.

Effects of organotins on growth and survival of two marine diatoms, Skeletonema costatum and Thalassiosira pseudonana

Abstract Tributyl- and triphenyltin compounds inhibited population growth and cell survival of marine unicellular algae at low concentrations. They may pose a threat to algae in areas of industrial outfalls and heavy boat traffic.

Kepone® bioconcentration, accumulation, loss, and transfer through estuarine food chains

Accumulation, transfer, and loss of Kepone in estuarine organisms were studied in laboratory bioassays. Kepone was bioconcentrated by oysters (Crassostrea virginica), mysids (Mysidopsis bahia), grass shrimp (Palaemonetes pugio), sheepshead minnows (Cyprinodon variegatus), and spot (Leiostomus xanthurus), from concentrations as low as 0.023 μg/l seawater. Bioconcentration factors ranged from 10 to 340 in static exposures and 900 to 13,500 in flow-through bioassays, and were dependent on species and exposure duration.

Notes. Determination of bioactivity of chemical fractions of liquid wastes using freshwater and saltwater algae and crustaceans.

Complex wastes from industrial and municipal outfalls were fractionated chemically and tested for toxicity with freshwater and saltwater algae and crustaceans. The organic fraction of each waste was subfractionated into acid-, base-, and neutral-extractable portions, and the inorganic fraction was subfractionated into its anion and cation components. All wastes affected growth of the algae Skeletonema costatum (saltwater) and Monoraphidium capricornutum (freshwater) or survival of Mysidopsis bahia (saltwater) and Daphnia magna (freshwater). Usually, bioactivity was limited to one or two subfractions. In some cases, algal growth was stimulated by a fraction or subfraction, whereas stimulation was not detected in whole waste. It is suggested that fractionation must be done in order to estimate the full potential impact of complex wastes on aquatic systems. The method can also be used to identify toxic factors before application of cost-effective control technology.

Algae and crustaceans as indicators of bioactivity of industrial wastes

Abstract Freshwater ( Selenastrum capricornutum ) and marine ( Skeletonema costatum ) algae were exposed to liquid wastes from 10 industrial sites in laboratory bioassays. All wastes affected algal growth, either by stimulation only or by stimulation at low concentrations and inhibition at high concentrations. Generally, S. capricornutum and Sk. costatum responded similarly to each waste: SC20s (concentration that stimulated growth by 20%) were between 0.01 and 20.0% waste; EC50s (concentration that inhibited growth by 50%), between 5.1 and 85.5% waste. Since toxicity to S. capricornutum was usually lost by the sixth or seventh day of exposure in all wastes except one, it is recommended that algal tests be carried out for 4 days. Both algal species were more sensitive to the wastes than were Daphnia magna (freshwater) and Mysidopsis bahia (marine). Only three wastes were toxic to D. magna and two were toxic to M. bahia . SC20 and EC50 values are used to calculate the 7-day, 10-year flow rate of the receiving stream required for dilution of effluents to non-toxic concentrations.

Inhibition of arm regeneration by Ophioderma brevispina (Echinodermata, Ophiuroidea) by tributyltin oxide and triphenyltin oxide

Effects of water-bourne toxicants on regeneration of arms by the brittle star, Ophioderma brevispina, are described. Regeneration was inhibited by 0.1 micrograms liter-1 bis(tri-n-butyltin)oxide and bis(triphenyltin)oxide. Both substances are known to act upon the nervous system, and it is suggested that inhibition was caused by neurotoxicological action of the tin compounds or by their direct effect upon tissue at the breakage point. The former is most likely because regeneration is mediated by the radial nerves of brittle stars.

A marine algal bioassay method: Results with pesticides and industrial wastes

A simple marine algal bioassay method is described for short- and long-term studies on pesticides and industrial wastes. It can be used for rapid screening of a variety of substances with single-species and multiplespecies tests and gives relative toxicities of the pollutants tested. Algae are grown in optically matched culture tubes that fit directly into a spectrophotometer, allowing population density to be estimated by absorbance without removal of samples. 96 h EC50 values for some pesticides and the diatomSkeletonema costatum are: EPN, 340 μg l−1; carbophenothion, 109 μg l−1; DEF, 366ug l−1; ethoprop, 8.4 mg l−1; methyl parathion, 5.3 mg l−1; and phorate, 1.3 mg l−1. Presence of the chelator EDTA in medium had no effect on toxicity of carbaryl toS. costatum, Nitzschia angularum, Chlorococcum sp. andChlorella sp. Liquid industrial wastes either stimulated growth, inhibited growth, or stimulated growth at low concentrations but inhibited it at higher concentrations. In mixed-species studies with the herbicide neburon, presence of a resistant species protected the sensitive species. Liquid industrial waste from a paper products plant caused changes in relative numbers, as compared to controls, whenS. costatum andPorphyridium cruentum were grown together.

Responses of marine unicellular algae to brominated organic compounds in six growth media

Marine unicellular algae, Skeletonema costatum, Thalassiosira pseudonana, and Chlorella sp. were exposed to the industrial brominated compounds tetrabromobisphenol A, decabromobiphenyloxide (DBBO), hexabromocyclododecane (HBCD), pentabromomethylbenzene (PBMB), pentabromoethylbenzene (PBEB), and the herbicide bromoxynil (BROM), in six algal growth media. High concentrations of DBBO (1 mg liter-1), PBMB (1 mg liter-1), and PBEB (0.5 mg liter-1) reduced growth by less than 50%. EC50s of the other compounds varied with growth medium, with high EC50/low EC50 ratios between 1.3 and 9.9. Lowest EC50s, 9.3 to 12.0 micrograms liter-1, were obtained with S. costatum and HBCD. It is concluded that responses to toxicants in different media are the results of interactions among algae, growth medium, toxicant, and solvent carrier.

Resistance of Red Mangrove (Rhizophora mangle L.) Seedlings to Lead, Cadmium, and Mercury

Seedlings of red mangrove (Rhizophora mangle) were treated twice with 25, 250, or 500 Ag Cd/g soil; 62.5, 125, or 250 jtg Pb/g soil; or 10, 100, or 500 Ag Hg/g soil. Survival of seedlings was affected only by 500 ,ug Hg/g soil. There was no effect of any metal on final weight and size of hypocotyls, stems, roots, or leaves; the time at which the stem emerged from the plumule; or the time at which the first pair of leaves unfurled from the stem. Lead was not translocated by the seedlings but Cd and Hg were. It is suggested that tolerance of R. mangle seedlings to high concentrations of Cd, Pb, and Hg may be due to formation of non-toxic sulfides in the root or on its surface, detoxification in tissues, an ion-exclusion mechanism in the roots, or a combination of these factors. HIGHER PLANT SPECIES VARY WIDELY in resistance to high concentrations of heavy metals in soils, and resistance may vary at the subspecies level. Gregory and Bradshaw (1965) described metal-tolerant ecotypes of Agrostis tenuis that grew on toxic mining soil, and Wu and Antonovics (1976) showed that an ecotype of Plantago lanceolata that grew near a roadside contaminated by lead was more resistant to lead than were unexposed ecotypes. The mechanism of tolerance to heavy metals by higher plants is not known, but Antonovics et al. (1971) suggested that they detoxify heavy metals by chelation at the cell wall. In mangrove soil, where there is an abundance of sulfides, heavy metals may be precipitated in sulfide complexes and thus be made unavailable to the plants. Another mechanism for resistance could be exclusion of ions by roots. Scholander et al. (1962) showed that roots of the mangrove genus Rhizophora contain an osmoregulatory mechanism for exclusion of ions. We exposed seedlings of Rhizophora mangle L. to very high concentrations of lead, cadmium, and mercury with subsequent measurements of residues in plant parts and of increases in biomass. We hypothesized that lack of translocation would indicate metal exclusion and that high tissue residues without effect would indicate detoxification at the tissue level. MATERIALS AND METHODS Five hundred ripe R. mangle seedlings were picked from trees near Naples, Florida, and shipped to, the Gulf Breeze laboratory. There, they were separated into 10 groups of 40 seedlings, each of similar average hypocotyl length and weight. Each seedling was planted in a drainless clay not. 90 mm tall and 63 mm in diameter. Each pot contained between 269 and 281 g (average 272 g) of muddy sand from the head of Escambia Bay, Florida. The sediment was passed through a 1 cm2-mesh screen and was, kept under natural estuarine water of 28.5 ppt (parts per thousand) salinity. Soil pH and Eh were determined on a Corning model 7 pH meter. The sediment was analyzed for chlorinated insecticides and polychlorinated biphenyls (PCBs) by extraction with 10 percent acetone in petroleum ether, cleaned-up in a Florisil column, and analyzed by electron capture gas chromatography (Duke et al. 1970). The organic content of four substratum aliquots was determined by drying for 16.5 hrs at 106?C and ashing for 6 hrs at 525?C. The loss of weight upon ashing was considered to be equal to the weight of organic matter. The results are given as the average of the four samples. Lead and cadmium in soil and plant parts were analyzed by flame and flameless atomic absorption spectrophotometry (Segar, in press). Samples were wet ashed with HN03-H2S04 ( 1:1 ) in a microwave oven (Abu-Samra et al. 1975). Mercury was determined after wet ashing by the method of Hatch and Ott (1968), and total sulfur by the method of Blanchar et al. (1965). Before planting, weight and hypocotyl length were recorded for each seedling. During the tests, total weight and weight of roots, hypocotyl, stem, and leaves were determined. Also, length of hypocotyl and stem and length and width of leaves were measured. Times of appearance of the stem and leaves were also noted. Seedlings were grown at 250?+1?0C under 6000 lux from cool white fluorescent tubes with alternating 12-hr periods of light and darkness. Water was 1Publication No. 324 from the Gulf Breeze Laboratory. 22 BIOTROPICA 11(1): 22-27 1979 This content downloaded from 207.46.13.122 on Thu, 19 May 2016 05:05:30 UTC All use subject to http://about.jstor.org/terms added twice daily to each pot. On the first day, the pots were watered with natural estuarine water of 28.5 ppt salinity. Thereafter, deionized water was used. Soil was treated twice with lead, cadmium, or mercury. The first treatment occurred one week after planting; the second, when seedlings had one pair of leaves. Treatment concentrations were: lead, 62.5, 125, and 250 jug/g soil; cadmium, 25, 250, and 500 ,ug/g soil; mercury, 10, 100, and 500 jug/g soil. All were added as the chloride salt dissolved in deionized water. One-half of the seedlings were collected one week after the first pair of leaves unfolded from the stem. The other half was treated a second time and collected two weeks later. They were examined for chlorosis, epinasty, abscission, and other gross changes. Data were analyzed by the t statistic for two means (Brownlee 1965).