Influence of initial substratum surface tension on marine micro- and macro-fouling in the Gulf of Thailand

The density of five major groups of fouling organisms (bacteria, diatoms, choanoflagellates, ciliates, macroorganisms) on seven artificial substrata with surface tensions between 19.0 and 64.5 mN m⁻¹ was studied in the Gulf of Thailand. Two series of test panels of the different substrata were immersed into the sea between 3 hours and 64 days (macrofauna 128 days). The results show that surface tension has a limited impact on the density of the organisms. Only bacteria settled continuously in significantly lower numbers on materials within the minimum bioadhesive range (20–25 mN m⁻¹) than on other substrata. Significant differences between the substrata may disappear after long exposure, as in series 2 after 16 days. For diatoms and protozoa, a colonisation pattern similar to that of bacteria with a minimum of 20–25 mN m⁻¹ was detected after several exposure intervals. However, it was never recorded in more than 3 exposure intervals in a row. The colonisation pattern of macroorganisms could not be attributed to substratum surface tension. An index, called “colonisation degree” is introduced to give a general impression of the density of organisms on the materials tested. The colonisation degree did not show any significant difference at any exposure interval. The present results clearly suggest that substratum surface tension is easily overshadowed by other factors in colonisation processes under natural conditions. *** DIRECT SUPPORT *** A03B6037 00003     

Experimental studies of rapid bioerosion of coral reefs in the Galápagos Islands

Experimental carbonate blocks of coral skeleton,Porites lobata (PL), and cathedral limestone (LS) were deployed for 14.8 months at shallow (5–6 m) and deep (11–13m) depths on a severely bioeroded coral reef, Champion Island, Galápagos Islands, Ecuador. Sea urchins (Eucidaris thouarsii) were significantly more abundant at shallow versus deep sites.Porites lobata blocks lost an average of 25.4 kg m^–2yr^–1 (23.71 m^–2yr^–1 or 60.5% decrease yr^–1). Losses did not vary significantly at depths tested. Internal bioeroders excavated an average of 2.6 kg m^–2 yr^–1 (2.41 m^–2 yr^–1 or 0.6% decrease yr^–1), while external bioeroders removed an average of 22.8 kg m^–2 yr^–1). (21.31 m^–2 yr^–1). or 59.9% decrease yr^–1). few encrusting organisms were observed on the PL blocks. Cathedral limestone blocks lost an average of 4.1 kg m^–2 yr^–1). (1.81 m^–2 yr^–1). or 4.6% decrease yr-'), also with no relation to depth. Internal bioeroders excavated an average of 0.6 kg m^–2 yr^–1). (0.31 m^–2 yr^–1). or 0.7% decrease yr^–1). and external bioeroders removed an average of 3.5 kg m^–2 yr^–1). (1.51 m^–2 yr^–1). or 3.9% decrease yr^–1). from the LS blocks. Most (57.6%) encrustation occurred on the bottom of LS blocks, and there was more accretion on block bottoms in deep (61.4 mg cm^–2 yr^–1). versus shallow (35.0 mg cm^–2 yr^–1) sites. External bioerosion reduced the average height of the reef framework by 0.2 cm yr^–1). for hard substrata (represented by LS) and 2.3 cm yr^–1). for soft substrata (represented by PL). The results of this study suggest that coral reef frameworks in the Galápagos Islands are in serious jeopardy. If rates of coral recruitment do not increase, and if rates of bioerosion do not decline, coral reefs in the Galápagos Islands could be eliminated entirely.     

Investigation of potential biosurfactant production among phytopathogenic corynebacteria and related soil microbes

PhytopathogenicCorynebacterium species and related soil microbes were examined for their ability to produce surfactants from hydrocarbon substrate. Surfactant production was detected by the lowering of both surface and interfacial tensions, by the formation of high reciprocal critical micelle concentrations (CMCs), and by the possession of properties of emulsification and demulsification. Whole broth cultures of severalC. fascians strains,C. insidiosum ICPB CI13A,Arthrobacter paraffineus NRRL B-3453, andNocardia amarae NRRL B-8176 lowered surface tensions from 58.5 mN/m to 27–33 mN/m, lowered interfacial tensions from 33.5 mN/m to 0.55–4.0 mN/m, and had high reciprocal CMCs. Whole-broth cultures ofN. amarae NRRL B-8176 had excellent demulsification ability; those of someC. fascians strains andC. insidiosum ICPB CI13A produced unusual gel-like emulsions. These properties are believed to aid in the attachment of phytopathogenic corynebacteria to the surfaces of host plants.     

Extracellular polysaccharides of a copper-sensitive and a copper-resistant Pseudomonas aeruginosa strain: synthesis,chemical nature and copper binding

Extracellular polysaccharides (EPS) of a copper-sensitive (Cu^s) and a copper-resistant (Cu^r) Pseudomonas aeruginosa strain were investigated in terms of their production, chemical nature and response towards copper exposure. The extent of EPS synthesis by the resistant strain (4.78 mg mg^–1 cell dry wt.) was considerably higher over its sensitive counterpart (2.78 mg mg^–1 dry wt.). FTIR-spectroscopy and gas chromatography revealed that both the polymers were acidic in nature, containing alginate as the major component along with various neutral- and amino-sugars. Acid content in the Cu^r EPS (480.54 mg g^–1) was greater than that in the Cu^s EPS (442.0 mg g^–1). Presence of Cu²⁺ in the growth medium caused a dramatic stimulation (approximately 4-fold) in EPS synthesis by the Cu^r strain, while in a similar condition, the Cu^s failed to exhibit such response. The polymer of the resistant strain showed elevated Cu²⁺ binding (320 mg g^–1 EPS) compared to that of the sensitive type (270 mg g^–1). The overall observations show the potential of the Cu^r EPS for its deployment in metal bioremediation.     

Trophic significance of herbivorous macroinvertebrates on the central Great Barrier Reef

The common herbivorous macroinvertebrates on reef flats of the central Great Barrier Reef (GBR) were, in order of abundance: gastropod molluscs (Turbo and Trochus spp.); pagurid crabs; and the starfish, Linckia laevigata. The density of macroinvertebrates on Davies Reef was lowest in the thick-turf habitats at the windward reef-crest (0.6–0.9 m^–2) compared with 3.1 to 5.2 m^–2 elsewhere on the reef flat. Invertebrate grazer densities were similar on mid-shelf reef flats (mean: 2.3–3.6 m^–2) and significantly lower on outer-shelf reefs (0.3–1.0 m^–2). The ingestion rate of Turbo chrysostomus, the most abundant macroinvertebrate species, was derived from (a) faecal production and food absorption efficiency, (b) comparison of algal biomass on grazed and ungrazed natural substrata and (c) gut-filling rate and feeding periodicity in field populations. The ingestion rate of Trochus pyramis, the most common trochid and an abundant component of the macroinvertebrate fauna, was also estimated using (a). This gastropod fed continuously, whereas T. chrysostomus showed a distinct nocturnal feeding periodicity. T. chrysostomus and T. pyramis ingested daily means of 35 and 54 mgC animal^-1, respectively. Total gastropod grazing rates (mgC m^–2d^-1 in the field ranged from 11 in a thick-turf, reef-crest habitat to 144 on the open-grazed main flat. Grazing by gastropods accounted for between 0.3 and 8% of the net production of benthic algal food resources, depending on location on the reef flat. Across the whole reef flat the mean (areally-weighted) gastropod grazing rate was 6% of net production. A comparison of the relative roles of different types of grazers led to the conclusion that fishes are likely to have the greatest overall trophic impact on reefs of the central GBR. Even where macroinvertebrates are most abundant on reef flats, the yield from benthic algal communities to macroinvertebrates is estimated to be only one third of that due to fishes.Contribution no. 471 from the Australian Institute of Marine Science     

Temporal variations in phytoplankton primary production in a tropical reservoir (Barra Bonita,SP – Brazil)

Temporal variations of phytoplankton primary production in Barra Bonita Reservoir (22° 29 5 S, 48° 34 W, São Paulo State, Brazil) were evaluated by monthly in situ observations in the period July 1993 to June 1994 and by frequent (every 2 days for 4 weeks) sampling during the dry and colder (July) and wet and warmer (January/February) periods. Highest primary production was observed in April (654 mgC m^–2 h^–1), which also coincided with the period of longest theoretical water retention time. In July, the primary production was the lowest (20 mgC m^–2 h^–1). Nanoplankton production was the highest in October (192 mgC m^–2 h^–1) corresponding to 81% of the total. June represented the period with the lowest share of nanoplankton production (17%, 9 mgC m^–2 h^–1). Nanoplankton was predominant during 8 of the 12 months of observation, representing an average of 41% of the total community primary production. During January/February, most organisms were smaller than 20 m. Microphytoplankton production was higher in the colder and dryer period. The production values found during the periods of intensive measurements were higher in the wet January/February period, with the average value of 135 mgC m^–2 h^–1, while the lowest production values were found in the dry winter (July) when they represented 90 mgC m^–2 h^–1. The cause of the high January values was partially bigger loads of nutrients from the watershed during the high flow, but probably also faster nutrient regeneration at higher temperatures. Barra Bonita primary production is currently three times higher than that observed 15 years ago.     

The importance of grazing food chain for energy flow and production in three intertidal sand bottom communities of the northern Wadden Sea

In three intertidal sand bottom communities of the Königshafen (Island of Sylt, North Sea), the biomass production and respiration of phytobenthos, phytoplankton, macrozoobenthos, and in situ community metabolism were measured monthly during 1980. The study sites were characterized by different communities (Nereis-Corophium-belt, seagrass-bed,Arenicola-flat) and by a high abundance of the molluscHydrobia ulvae. Benthic diatoms are the major constituents of plant biomass in theArenicola-flat. In this community, gross primary productivity amounts to 148 g C m^–2 a^–1. 82 % of this productivity is caused by microbenthos, whereas phytoplankton constitutes only 18 %. In the seagrass-bed, gross primary productivity amounts to 473 g C m^–2 a^–1. 79 % of this is generated by seagrass and its epiphytes, whereas microphytobenthos contributes 19 %. In theNereis-Corophium-belt, only microphytobenthos is important for biomass and primary productivity (gross: 152 g C m^–2 a^–1). Annual production of macrofauna proved to be similar in theArenicola-flat (30 g C m^–2 a^–1) to that in the seagrass-bed (29 g C m^–2 a^–1). Only one third of this amount is produced in theNereis-Corophium-belt (10 g C m^–2 a^–1). The main part of secondary production and animal respiration is contributed by grazingH. ulvae. In the seagrass-bed, 83 % of the energy used for production is obtained from the grazing food chain. In theArenicola-flat and theNereis-Corophium-belt, the importance of non-grazing species is greater. A synchrony of seasonal development of plant biomass and monthly secondary production was observed. In theArenicola-flat and the seagrass-bed, where density and production of macrofauna are high, a conspicuous decrease in biomass of microbenthos occurs during the warmer season, whereas in theNereis-Corophium-belt primary production causes an increase in microphytobenthic biomass in summer and autumn. Energy flow through the macrofauna amounts to 69 g C m^–2 a^–1 in theArenicola-flat, 85 g C m^–2 a^–1 in the seagrass-bed and 35 g C m^–2 a^–1 in theNereis-Corophium-belt. Based on the assumption that sources of food are used in proportion to their availability, 49 g C m^–2 a^–1 (Arenicola-flat), 72 g C m^–2 a^–1 (seagrass-bed) and 26 g C m^–2 a^–1 (Nereis-Corophium-belt) are estimated as taken up by the grazing food chain. All three subsystems are able to support the energy requirements from their own primary production and are not dependent on energy import from adjacent ecosystems.     

Production,Respiration, and Overall Carbon Balance in an Old-growth <Emphasis Type="Italic">Pseudotsuga</Emphasis>-<Emphasis Type="Italic">Tsuga</Emphasis> Forest Ecosystem

Ground-based measurements of stores, growth, mortality, litterfall, respiration, and decomposition were conducted in an old-growth forest at Wind River Experimental Forest, Washington, USA. These measurements were used to estimate gross primary production (GPP) and net primary production (NPP); autotrophic respiration (R_a) and heterotrophic (R_h) respiration; and net ecosystem production (NEP). Monte Carlo methods were used to calculate uncertainty (expressed as ± 2 standard deviations of 200–400 calculations). Live carbon (C) stores were 39,800 g C m^–2 (34,800–44,800 g C m^–2). The store of C in detritus and mineral soil was 22,092 g C m^–2 (20,600–23,600 g C m^–2), and the total C stores were 61,899 g C m^–2 (56,600–67,700 g C m^–2). Total NPP was 597 g C m^–2 y^–1 (453 to 741 g C m^–2 y^–1). R_a was 1309 g C m^–2 y^–1 (845–1773 g C m^–2 y^–1), indicating a GPP of 1906 g C m^–2 y^–1 (1444–2368 g C m^–2 y^–1). R_h, including the respiration of heart rots in tree boles, was 577 g C m^–2 y^–1 (479–675 g C m^–2 y^–1). Long-term NEP was estimated to be +20 g C m^–2 y^–1 (–116 to +156 g C m^–2 y^–1), indicating this stand might be a small sink. These estimates contrast with the larger sink estimated at the same site using eddy-flux methods. Several hypotheses to explain this discrepancy were explored, including (a) undetected biomass increases, (b) underestimates of NPP, (c) unmeasured losses, and (d) a temporal mismatch between the two sets of measurements. The last hypothesis appears the most likely.     

Formation and analysis of mannosylerythritol lipids secreted by Pseudozyma aphidis

Pseudozyma aphidis DSM 70725 was found to be a novel producer of mannosylerythritol lipids (MELs). The MELs were quantified by HPLC. Glucose as carbon source for precultivation supported growth well. By contrast, at concentrations >30 g l^–1 in preculture, subsequent MEL formation in the main culture with soybean oil as sole carbon source was reduced. The type of substrate supply considerably influenced MEL formation. High concentrations of soybean oil (80 ml l^–1) at init favored the production process when compared to a stepwise (20 ml l^–1) addition. Mannose or erythritol were suitable second carbon sources that enhanced the MEL yield with soybean oil as preferred primary substrate. After 10 days, a maximum yield of 75 g l^–1 was attained during shake-flask cultivation. Biofuel (rapeseed oil methyl ester) also resulted in high yields of MEL, but glucose reduced the MEL yield. Analysis by GC-MS showed that all fatty acids contained in MEL and derived from soybean oil or related methyl ester were degraded by C2-units to differing extents. The surface (water/air) and interfacial (water/hexadecane) tension of the MELs produced from different carbon sources were reduced to a minimum of 26.2 mN m^–1 and 1 mN m^–1, respectively.     

Observations on the distribution patterns,behaviour, diets and reproductive cycles of sand-dwelling clinids (Perciformes: Clinidae) from South Africa

Synopsis Twenty-two samples of sand-dwelling fishes were collected from sublittoral sandy substrata off the Cape Peninsula, South Africa using a novel quantitative technique in which the ichthyocide, rotenone, was introduced beneath 6.25 m² plastic sheets weighted around the perimeter with chain. A total of 94 fish of eight species and four families were recorded. Of these, four species of the family Clinidae made up 92% of the material. Fish densities varied from 0.10–2.96 fish m^–2 (0.17–1.14 g m^–2). Distribution patterns amongst the Clinidae were explained by sediment particle size, with all of the newly discovered species, Cancelloxus longior, inhabiting fine sand (median grain size 0.25–0.50 mm), and all Xenopoclinus leprosus, C. elongatus and Pavoclinus smalei occurring in gravel (> 1 mm). Xenopoclinus kochi was found in all sediment types, but was most abundant in coarse substrata. Diets of all four species were similar, consisting chiefly of amphipods and isopods. However, small differences in prey preference were evident. All four species reached sexual maturity at 25–30 mm standard length, were viviparous, exhibited superembryonation and gave birth to live young of approximately 14 mm. Breeding seasonality occurred in all species except P. smalei.     

Influence of medium composition and aeration on the synthesis of biosurfactants produced by Candida antarctica

Candida antarctica synthesised surface-active mannosylerythritol lipids at 46 g l^–1 by adding 80 g soybean oil l^–1 to the medium and maintaining the pO₂ at 50% with an air flow rate 1 vvm. Two-stage culturing of C. antarctica avoided medium foaming but the yield of biosurfactants synthesis was 28 g l^–1. The biosurfactants decreased the surface tension of water to 35 mN m^–1.     

Biofiltration of waste gases with the fungi Exophiala oligosperma and Paecilomyces variotii

Two biofilters fed toluene-polluted air were inoculated with new fungal isolates of either Exophiala oligosperma or Paecilomyces variotii, while a third bioreactor was inoculated with a defined consortium composed of both fungi and a co-culture of a Pseudomonas strain and a Bacillus strain. Elimination capacities of 77 g m^–3 h^–1 and 55 g m^–3 h^–1 were reached in the fungal biofilters (with removal efficiencies exceeding 99%) in the case of, respectively, E. oligosperma and Paecilomyces variotii when feeding air with a relative humidity (RH) of 85%. The inoculated fungal strains remained the single dominant populations throughout the experiment. Conversely, in the biofilter inoculated with the bacterial–fungal consortium, the bacteria were gradually overgrown by the fungi, reaching a maximum elimination capacity around 77 g m^–3 h^–1. Determination of carbon dioxide concentrations both in batch assays and in biofiltration studies suggested the near complete mineralization of toluene. The non-linear toluene removal along the height of the biofilters resulted in local elimination capacities of up to 170 g m^–3 h^–1 and 94 g m^–3 h^–1 in the reactors inoculated, respectively, with E. oligosperma and P. variotii. Further studies with the most efficient strain, E. oligosperma, showed that the performance was highly dependent on the RH of the air and the pH of the nutrient solution. At a constant 85% RH, the maximum elimination capacity either dropped to 48.7 g m^–3 h^–1 or increased to 95.6 g m^–3 h^–1, respectively, when modifying the pH of the nutrient solution from 5.9 to either 4.5 or 7.5. The optimal conditions were 100% RH and pH 7.5, which allowed a maximum elimination capacity of 164.4 g m^–3 h^–1 under steady-state conditions, with near-complete toluene degradation.     

Dynamics of coexisting Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus populations in a high-Arctic fjord

We studied the population dynamics of Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus in Billefjorden, Svalbard (78°40N). All three species reproduced in the fjord with different timing. The maximum abundance of Calanus spp. copepodite stages peaked on the 11th of July (29,000 ind m^–2). C. glacialis was the dominant species accounting for 60–80% of the total Calanus abundance. C. finmarchicus appear to thrive in the fjord despite the low temperatures (–1.86°C to 5°C) and accounted for 20–30% of the total population. C. hyperboreus contributed less to the total abundance (5–20%). A 1-year life cycle is suggested for C. finmarchicus and C. hyperboreus in the fjord, C. glacialis has a 1- to 2-year life cycle. Highest mortality rates were observed for copepodite stage CV in C. finmarchicus and C. glacialis (0.09 and 0.075 d^–1, respectively) and for females in C. hyperboreus (0.149 d^–1). Mortality of copepodite stages was substantially lower in C. glacialis than in the other species. This is particularly obvious in the early and numerous copepodite stages (CI + CII) during the period of recruitment to these stages. This suggests that differences in secondary production in Arctic pelagic ecosystems are controlled partly by population loss rates.     

Acid hydrolysis and quantitative determination of total hexosamines of an exopolysaccharide produced by <Emphasis Type="Italic">Citrobacter</Emphasis> sp.

During the hydrolysis of an exopolysaccharide (EPS) produced by Citrobacter sp., the maximum liberation of hexosamine was obtained with 6 m HCl at 115 °C in an autoclave for 1 h. The glycosidic bond energy and degree of acetylation of the hexosamine in EPS were approximately 77 kJ mol^–1 and 61%, respectively. Thermal destruction of the hexosamines and the effect of salt on the hexosamine determination could be minimized under the optimized hydrolytic conditions. Using a modified Elson–Morgan method, maximum total hexosamine concentration was determined to be 3.2 g l^–1 (29% of crude EPS) after 96 h of fed-batch culture.Revisions requested 18 August 2004; Revisions received 2 November 2004     

The effect of sewage-enriched river Ganga water on the biomass production of theAzolla-Anabaena complex

The biomass formation ofAzolla was greatly enhanced by water of the River Ganga and by prevailing environmental conditions. It increased gradually from January to April (first maximum 2.409 g.m^–2.day^–1), declined during June (1.185 g.m^–2.day^–1), and reached a second its maximum during September (2.629 g.m^–2.day^–1). The biomass formation was related to the nutrient availability in the medium in a particular season (measured were: nitrate-N, available phosphorus, total suspended solids, and conductivity). The average annual production of 6.73 ton.ha^–1.yr^–1 is equivalent to the average production of 0.025 ton.ha^–1.yr^–1 phosphorus, 0.252 ton.ha^–1.yr^–1 nitrogen, and 1.57 ton.ha^–1.yr^–1 crude protein.     

Biomass and production of Argyrodiaptomus furcatus,a tropical calanoid copepod in Broa Reservoir,southern Brazil

The biomass and the production of Argyrodiaptomus furcatus (Sars), the most abundant copepod in Broa Reservoir (São Carlos, São Paulo State), were estimated, determining in the laboratory the development time and the quantity of organic carbon and establishing the relationship between these two parameters. The daily production was calculated from P = B(1- e^gt) and the annual production was obtained by integrating daily production against time. The maximum production of Argyrodiaptomus furcatus in the reservoir depends on the region considered and on the period of the year. The maximum production was 45.15 mg C m^–3d^–1 in March, 1976 at station II, region of macrophytes and 6.74 mg C m^–3d^–1 at station IV, near the dam. The mean production for the year is 6.26 mg C m^–3d^–1 at station II and 1.43 mg C m^–3d^–1 at station IV.     

Size-frequency estimates of secondary production byMysis relicta in Lakes Michigan and Huron

Data from five Great Lakes studies ofMysis relicta populations were reanalyzed to calculate secondary production estimates using the size-frequency method. Production estimates (P) ranged from 0.25 to 3.2 g dry weight m^–2 yr^–1. Average annual biomass {xxB} and mean annual density (xxD) were 0.11–1.11 g dry weight/ m² and 25–434 animals/ m², respectively. P:{xxB} ratios varied only between 2.2 and 3.3. Maximum and minimum biomass values within a study varied by a factor of 519 for one study but by less than 17 for the others. Highest estimates of P, {xxB} and {xxD} were calculated for collections from a 50-m station in Lake Michigan despite the larger populations suspected to be present at greater depths sampled in the other studies. These conservative estimates provide a basis for scaling trophic interactions involvingM. relicta and emphasize findings by previous workers that night-time sampling with vertical net hauls is the best available technique for quantitative studies ofM. relicta populations in the Great Lakes.     

Landscape patterns of CH4 fluxes in an alpine tundra ecosystem

We measured CH₄ fluxes from three major plant communities characteristic of alpine tundra in the Colorado Front Range. Plant communities in this ecosystem are determined by soil moisture regimes induced by winter snowpack distribution. Spatial patterns of CH₄ flux during the snow-free season corresponded roughly with these plant communities. InCarex-dominated meadows, which receive the most moisture from snowmelt, net CH₄ production occurred. However, CH₄ production in oneCarex site (seasonal mean=+8.45 mg CH₄ m^–2 d^–1) was significantly larger than in the otherCarex sites (seasonal means=–0.06 and +0.05 mg CH₄ m^–2 d^–1). This high CH₄ flux may have resulted from shallower snowpack during the winter. InAcomastylis meadows, which have an intermediate moisture regime, CH₄ oxidation dominated (seasonal mean=–0.43 mg CH₄ m^–2 d^–1). In the windsweptKobresia meadow plant community, which receive the least amount of moisture from snowmelt, only CH₄ oxidation was observed (seasonal mean=–0.77 mg CH₄ m^–2 d^–1). Methane fluxes correlated with a different set of environmental factors within each plant community. In theCarex plant community, CH₄ emission was limited by soil temperature. In theAcomastylis meadows, CH₄ oxidation rates correlated positively with soil temperature and negatively with soil moisture. In theKobresia community, CH₄ oxidation was stimulated by precipitation. Thus, both snow-free season CH₄ fluxes and the controls on those CH₄ fluxes were related to the plant communities determined by winter snowpack.     

Secondary production of Rhyacophila minora,Ameletus sp., and Isonychia bicolor from streams of low and circumneutral pH in the Appalachian Mountains of West Virginia

We estimated the secondary production of Rhyacophila minora, Ameletus sp., and Isonychia bicolor in three acidic streams and one circumneutral stream in Randolph County, West Virginia. Quantitative benthic samples were collected monthly from these second-order streams from November 1990 to October 1991. Mean pH values in the acidic streams were 4.5, 4.8, and 4.8, and mean pH in the circumneutral stream was 6.7. Production estimates for Rhyacophia minora in the acidic streams were 49.6, 19.2, and 15.8 mg m^–2 y^–1. Production of R. minora in the circumneutral stream was 1.0 mg m^–2 y^–1. Ameletus sp. production estimates for the acidic streams were 144.8, 176.8, and 208.3 mg m^–2 y^–1. Ameletus sp. production in the circumneutral stream was 7.4 mg m^–2 y^–1. Secondary production of I. bicolor in the circumneutral stream was 116.6 mg m^–2 y^–1. No Isonychia were collected from the acidic streams. The higher production of R. minora and Ameletus sp. in the acidic streams may be associated with differences in macroinvertebrate community structure.     

Optimization of submerged culture conditions for exopolysaccharide production in <Emphasis Type="Italic">Sarcodon aspratus</Emphasis> (Berk) S.lto TG-3

The effect of medium components (carbon, nitrogen, and mineral sources) and environmental factors (initial pH and temperature) for mycelial growth and exopolysaccharide (EPS) production in Sarcodon aspratus(Berk) S.lto TG-3 was investigated. The optimal temperature (25°C) and initial pH (5.0) for the EPS production in shake flask cultures of S. aspratus were determined using the two-dimensional contour plot. The most suitable carbon, nitrogen, and mineral sources for EPS production were glucose, yeast extract, CaCl₂ and KH₂PO₄, respectively. Notably, the EPS production was significantly enhanced by supplementation of calcium ion. Subsequently, the optimum concentration of glucose (30gl^–1), yeast extract (15gl^–1), CaCl₂ (1.1gl^–1), and KH₂PO₄ (1.2gl^–1) were determined using the orthogonal matrix method. The effects of nutritional requirement on the mycelial growth of S.aspratuswere in regular sequence of glucose>KH₂PO₄>yeast extract>CaCl₂, and those on EPS production were in the order of glucose>yeast extract>CaCl₂>KH₂PO₄. Under the optimal culture conditions, the maximum EPS concentration in a 5-l stirred-tank reactor was 2.68gl^–1 after 4days of fermentation, which was 6-fold higher than that at a basal medium. The two-dimensional contour plot and orthogonal matrix method allowed us to find the relationship between environmental factors and nutritional requirement by determining optimal operating conditions for maximum EPS production in S.asparatus. The statistical experiments used in this work can be useful strategies for optimization of submerged culture processes for other mushrooms.