Sulfide as an environmental factor and toxicant: tolerance and adaptations in aquatic organisms
MetadataShow full item record
Cited times in Scopus
This review brings together a large number of independent and seemingly unrelated studies in various disciplines under four major topics: (1) sulfide as an environmental factor in aquatic habitats; (2) sulfide as a toxicant; (3) sulfide tolerance of aquatic organisms; and (4) adaptations limiting sulfide toxicity. Sulfide is widely distributed in the aquatic environment, but has been largely overlooked as an environmental factor for aquatic organisms. Sulfide at nanomoiar to millimolar concentrations adversely affects cytochrome c oxidase, various other enzymes, oxygen transport proteins, cellular structures, and consequently the physiological functions of organisms. These toxic effects are well documented in the biomedical literature, and also occur in the aquatic organisms that have been studied. Sulfide tolerance varies widely among protozoans, sediment meiofauna, polychaetes, bivalves, crustaceans, marine and freshwater fishes, and aquatic plants, often in correlation with the relative sulfide levels in the respective habitats. Aquatic organisms have evolved various adaptations against sulfide toxicity, possibly several acting in concert. Most animals are able to avoid and escape from sulfide, but cannot exclude sulfide from the body. No sulfide-resistant cytochrome c oxidase has been demonstrated, and most animals are capable of some degree of anaerobic meabolism. Various invertebrates have entered into symbiotic associations with sulfide-oxidizing bacteria. Some of these invertebrates immobilize and transport sulfide by means of sulfide-binding proteins or persulfides in the blood. Detoxication of sulfide occurs by methylation, non-specific oxidation, and enzymatic oxidation by mitochondria. Oxidative detoxication of sulfide to thiosulfate by mitochondria is common to several major taxa (protozoan, mollusk, teleosts, mammal), and is effective at low micromolar sulfide concentrations. Among organisms lacking sulfide-oxidizing bacterial symbionts, the mitochondria may thus provide the chief defense against environmental sulfide, and may allow the whole organism to tolerate sulfide concentrations 2–3 orders of magnitude greater than would inhibit cytochrome c oxidase.
CitationBagarinao, T. (1992). Sulfide as an environmental factor and toxicant: tolerance and adaptations in aquatic organisms.
- Journal Articles 
Showing items related by title, author, creator and subject.
Conference paperSM Aypa - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - Aquaculture Department, Southeast Asian Fisheries Development CenterAquaculture is regarded as the most promising source of protein food in the years ahead. Milkfish and Nile tilapia are the major fishes now produced but groupers, sea bass, rabbitfish, red snappers, carps, and catfishes are grown by some farmers. The tiger shrimp is still the most important cultured crustacean, but white shrimps and mudcrabs also have great potential. Oysters and mussels are produced in considerable amounts. Mariculture of the seaweed Eucheuma is now a well established industry, and the pond culture of Gracilaria for agar extraction is beginning to take off.
Resistance of two Nile tilapia, Oreochromis niloticus (L.) strains exposed to a mixture of zinc, cadmium and inorganic mercury MLA Cuvin-Aralar - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development CenterTwo strains of one month-old Oreochromis niloticus namely CLSU (obtained from Central Luzon State University, Philippines) and NIFI (from National Inland Fisheries Institute, Thailand) were exposed to a sublethal mixture of 1.0 mg L-1 Zn, 0.1 mg L-1 Cd, and 0.01 mg L-1 Hg for two months in aquaria. Another set served as control with only BFS tapwater in the aquaria. At the end of the exposure period the fish were grown for another 2 months in net cages in Laguna de Bay. During the exposure (aquarium) and grow-out (lake) phases, the uptake and elimination of the metals were determined by AAS. Accumulation of the metals peaked at 13.9 µg g-1 Hg, 78.5 µg g-1 Cd, and 1447.0 µg g-1 Zn for NIFI and 14.2 µg g-1 Hg, 82.4 µg g-1 Cd, and 1591.3 µg g-1 Zn for CLSU lost 94.9% Hg, 98.76% Cd, and 89.99% Zn after two months in the lake. After the grow-out period, 2 females and 1 male of each strain were stocked in replicate polyethylene tanks. Time to first spawning, spawning frequency, fry production, and fry survival (after 30 days) were monitored. Results showed no significant effect of treatment and strain with respect to time to first spawning, spawning frequency, and mean fry survival. There was also no significant difference between the treatment and strain in mean fry production when dam weight was used as a covariate in the analysis. The results suggest that both strains of O. niloticus are resistant to long-term exposure to the metals. In addition, the elimination of the metals during the grow-out phase may have also diminished their effect on the breeders of the two strains.
The sulfide tolerance of milkfish and tilapia in relation to fish kills in farms and natural waters in the Philippines Fish kills of milkfish Chanos chanos and tilapia Oreochromis spp. now occur frequently in brackish, marine, and freshwater farms (ponds, pens, and cages) in the Philippines. Aquafarms with high organic load, limited water exchange and circulation, no aeration, and high stocking and feeding rates can become oxygen-depleted and allow sulfide from the sediments to appear in the water column and poison free-swimming fish. The sulfide tolerance of 2-5 g milkfish and 5-8 g O. mossambicus was determined in 25-liter aquaria with flow-through sea water (100 ml min-1) at 26-30 °C and sulfide stock solutions pumped in at 1ml min-1. Total sulfide concentrations in the aquaria were measured by the methylene blue method and used in the regression against the probits of % survival. Four experiments showed that the two species have similar sulfide tolerance. In sea water of pH 8-8.5, about 163 ± 68 μM or 5.2 ± 2.2 mg l-1 total sulfide (mean ± 2 se) or 10 μM or 313 μg l-1 H2S was lethal to 50% of the fish in 4-8 h, and 61 ± 3 μM total sulfide or 4 μM H2S in 24-96 h (to convert all sulfide concentrations: 1 μM = 32 μg l-1). Earthen pond bottoms had 0-382 μM total dissolved sulfide (mean ± sd - 54 ± 79 μM, n - 76); a tenth of the samples had >200 μM. The water column may have such sulfide levels under hypoxic or anoxic conditions. To simulate some of the conditions during fish kills, 5-12 g milkfish were exposed to an abrupt increase in sulfide, alone or in combination with progressive respiratory hypoxia and decreasing pH. The tests were done in the same flow-through set-up but with sulfide pumped in at 25 ml min-1. The lethal concentration for 50% of the fish was 197 μM total sulfide or 12 μM H2S at 2 h, but 28-53 μM sulfide allowed fish to survive 6-10 h. Milkfish in aquaria with no aeration nor flow-through sea water died of respiratory hypoxia in 5-8 h when oxygen dropped from 6 to 1 mg l-1. Under respiratory hypoxia with 30-115 μM sulfide, the fish died in 2.5-4 h. Tests with low pH were done by pumping a weak sulfuric acid solution at 25 ml min-1 into aquaria with flow-through sea water such that the pH dropped from 8 to 4 in 5 h. Under these conditions, milkfish died in 7-9 h when the pH was 3.5. When 30-93 μM sulfide was pumped in with the acid, the fish died in 2-6 h when the pH was still 4.5-6.3. Thus, sulfide, hypoxia, and low pH are each toxic to milkfish at particular levels and aggravate each other's toxicity. Aquafarms must be well oxygenated to prevent sulfide toxicity and fish kills.