Journal articles: 'Epilithon production'

1

Hudson, J. J., J. C. Roff, and B. K. Burnison. "Measuring Epilithic Bacterial Production In Streams." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 9 (September 1, 1990): 1813–20. http://dx.doi.org/10.1139/f90-206.

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Techniques are presented for the measurement of bacterial production (by the rate of 3H-TdR incorporation into DNA), isotope dilution, time course of incorporation of nucleoside, and disturbance artifacts in natural epilithic (on rock) communities of headwater streams. The epilithon in riffles was subsampled by carefully chipping upper rock surfaces. Chips were placed in test tubes and incubated in situ. Test tubes were rotated to reduce the formation of artificial diffusion barriers to TdR transport. DNA was isolated using a double filtration technique. Summertime production had a range of 1.3–51 mg C∙m−2∙h−1 in five southern Ontario streams. Precursors to DNA synthesis, which diluted 3H-TdR, had a range of 63–440 nM. Incorporation of 3H-TdR was linear for at least 1 h. Disturbance artifacts did not appear from rock chipping or from extended sample rotation. The techniques can be applied to other microbial groups from various aquatic hard substrata.

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Hudson, J. J., J. C. Roff, and B. K. Burnison. "Bacterial Productivity in Forested and Open Streams in Southern Ontario." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 11 (November 1, 1992): 2412–22. http://dx.doi.org/10.1139/f92-267.

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Bacterial abundance, biomass, and heterotrophic production were measured in the water, sediment, and epilithon of forested and open streams in southern Ontario in summer 1988. Relationships of environmental variables to production were examined. The time course of nucleoside incorporation, recovery efficiency of bacterial DNA, isotope dilution, and disturbance artifacts were examined to compare bacterial production rates and to determine the appropriateness of the rate of [3H]thymidine incorporation into bacterial DNA as an estimate of bacterial production in these habitats. Water column bacterial biomass (12–97 μg C∙L−1) and heterotrophic production (0.21–67 μg C∙L−1∙h−1) were greater in open streams than in forested streams. Differences between open and forested stream sediment bacterial biomass (0.30–1.1 g C∙m−2) and heterotrophic production (18–140 mg C∙m−2∙h−1) were not as pronounced as they were in the water column. A methodological disturbance artifact may have introduced a minor bias in sediment production measurements. Epilithic bacterial biomass was 35–150 mg C∙m−2, and heterotroph production was 1.3–51 mg C∙m−2∙h−1, significantly greater (P < 0.05) in open streams than in forested streams. Epilithic production and stream water temperature were positively correlated (P < 0.05). Heterotrophic bacterial production exceeded net primary production in forested streams, but not in open streams.

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3

Fairchild, G. Winfield, and John W. Sherman. "Linkage between Epilithic Algal Growth and Water Column Nutrients in Softwater Lakes." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 8 (August 1, 1992): 1641–49. http://dx.doi.org/10.1139/f92-183.

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We examined the dependence of epilithic algal standing crop, production, and nutrient limitation upon water column nutrients in 12 softwater lakes of northeastern Pennsylvania. Elevated dissolved inorganic nitrogen accompanied low dissolved inorganic carbon in the more acidic lakes, while P varied little within the study area. The growth of epilithon on clay flower pot substrata diffusing combinations of N (NaNO3), P (Na2HPO4), and C (NaHCO3) was compared with growth on control substrata to evaluate which of the three nutrients limited growth in each lake. Standing crop accrual as chlorophyll a on control substrata averaged 0.8 μg/cm2, with little variation among lakes. Nutrient limitation of growth, however, was strongly related to lake alkalinity. Chlorophyll a was typically enhanced by N and/or P only in lakes with alkalinity greater than ~100 μeq/L and responded strongly to C enrichment in the two most acidic lakes. Combined addition of all three nutrients produced the largest chlorophyll a accrual in all 12 lakes. Invertebrate grazer biomass, dominated by chironomids in the more acidic lakes and by snails at higher alkalinity, was negatively related to chlorophyll a on these NPC substrata (r = −0.57, p = 0.05) and may have reduced algal standing crop well below nutrient-sustainable levels in some lakes.

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4

Guasch, Helena, and Sergi Sabater. "Estimation of the annual primary production of stream epilithic biofilms based on photosynthesisirradiance relations." Fundamental and Applied Limnology 141, no. 4 (March 24, 1998): 469–81. http://dx.doi.org/10.1127/archiv-hydrobiol/141/1998/469.

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5

Stock, Marsha S., and Amelia K. Ward. "Establishment of a Bedrock Epilithic Community in a Small Stream: Microbial (Algal and Bacterial) Metabolism and Physical Structure." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 11 (November 1, 1989): 1874–83. http://dx.doi.org/10.1139/f89-236.

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Patterns of epilithic algal and bacterial productivity were examined in a developing community on newly exposed stream bedrock for a period of 10 wk and in an undisturbed bedrock community used as a seasonal control. Physical and chemical changes were minimal over the experimental period. Bacterial colonization occurred initially and was rapidly followed by the development of a monolayer of adnate diatoms. Subsequent bacterial development coupled with maximum rates of bacterial productivity may have depended upon the algal cells for physical refugia, mucilage production, and/or other growth-promoting substrates present in algal photosynthate. After the diatom monolayer, filamentous algae developed despite the presence of high densities of snail grazers. By the end of the experiment, community composition on both substrata was generally similar although filamentous blue-green algae were a more important component of the native communities. Communities on newly exposed rock had higher total levels of epilithic productivity than on native rock where bacterial numbers averaged 2.26 × 1011 cells/m2. On native rock epilithic bacterial productivity averaged 72 mg C∙m−2∙d−1, yielding an average turnover time of 0.56 d; algal productivity averaged 224 mg C∙m−2∙d−1. These data suggested that epilithic production was not quantitatively limiting as a food resource for grazing snails in this stream during the summer months.

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6

Jónsson, Gunnar St, and Gunnar St Jonsson. "Photosynthesis and Production of Epilithic Algal Communities in Thingvallavatn." Oikos 64, no. 1/2 (May 1992): 222. http://dx.doi.org/10.2307/3545053.

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7

Guasch, Helena, and Sergi Sabater. "Primary production of epilithic communities in undisturbed Mediterranean streams." SIL Proceedings, 1922-2010 25, no. 3 (January 1994): 1761–64. http://dx.doi.org/10.1080/03680770.1992.11900484.

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8

Johnston, N. T., E. A. MacIsaac, P. J. Tschaplinski, and K. J. Hall. "Effects of the abundance of spawning sockeye salmon (Oncorhynchus nerka) on nutrients and algal biomass in forested streams." Canadian Journal of Fisheries and Aquatic Sciences 61, no. 3 (March 1, 2004): 384–403. http://dx.doi.org/10.1139/f03-172.

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We used natural variation in sockeye salmon (Oncorhynchus nerka) spawner biomass among sites and years in three undisturbed, forested watersheds in interior British Columbia to test the hypotheses that salmon were a major source of particulate organic matter inputs to the streams and that carcass biomass determined stream-water nutrient concentrations and epilithic algal production. Sockeye carcasses were retained at the spawning sites, primarily (7580%) by large woody debris (LWD) or pools formed by LWD. The abundance and distribution of sockeye salmon determined stream-water nutrient concentrations and epilithic chlorophyll a concentrations during late summer and early fall when most primary production occurred in the oligotrophic streams. Periphyton accrual rates were elevated at sites with high salmon biomass. Peak chlorophyll a concentration increased with increasing carcass biomass per unit discharge above a threshold value to reach maxima 10-fold greater than ambient levels. Epilithic algae were dominated by a few common, large diatom taxa. Salmon carcasses were the dominant source of particulate organic carbon in low gradient stream reaches. Nutrient budget modeling indicated that most of the salmon-origin nutrients were exported from the spawning streams or removed to the terrestrial ecosystem; diffuse impacts may extend over a much larger area than simply the sites used for spawning.

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Velasco, J., A. Millan, M. R. Vidal-Abarca, M. L. Suarez, C. Guerrero, and M. Ortega. "Macrophytic, epipelic and epilithic primary production in a semiarid Mediterranean stream." Freshwater Biology 48, no. 8 (July 15, 2003): 1408–20. http://dx.doi.org/10.1046/j.1365-2427.2003.01099.x.

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10

Peterson, Bruce, Brian Fry, Linda Deegan, and Anne Hershey. "The trophic significance of epilithic algal production in a fertilized tundra river ecosystem." Limnology and Oceanography 38, no. 4 (June 1993): 872–78. http://dx.doi.org/10.4319/lo.1993.38.4.0872.

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11

Augspurger, Clemens, and Kirsten Küsel. "Flow velocity and primary production influences carbon utilization in nascent epilithic stream biofilms." Aquatic Sciences 72, no. 2 (January 8, 2010): 237–43. http://dx.doi.org/10.1007/s00027-009-0126-y.

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12

Tsuchiya, K., A. Kohzu, VS Kuwahara, SiS Matsuzaki, M. Denda, and K. Hirabayashi. "Differences in regulation of planktonic and epilithic biofilm bacterial production in the middle reaches of a temperate river." Aquatic Microbial Ecology 87 (June 17, 2021): 47–60. http://dx.doi.org/10.3354/ame01968.

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To clarify the governing factors of planktonic and epilithic bacterial production (BP) and to quantify their relative contributions to the carbon cycle, we investigated the seasonal variation and regulatory factors of planktonic and epilithic BP in the middle reaches of the Shinano River, Japan, ecosystem from February 2019 to May 2020. Sampling was conducted at 3 stations: upper stream riffle, upper stream pool, and lower stream riffle, where current velocity, water depth, and bed shear stress were distinct. Planktonic and biofilm BP ranged from 5.5 to 466 mgC m-3 d-1 and 2.9 to 132 mgC m-2 d-1, respectively, showing clear seasonal variation. Biofilm BP was higher in the upper stream riffle than at the other stations, where no spatial variation in planktonic BP was observed. Generalized linear models suggest that BP was primarily regulated by water temperature. Additionally, planktonic BP was significantly correlated with dissolved organic carbon, suggesting carbon limitation. Biofilm BP showed no evidence of resource limitation (nutrients and organic matter), but was significantly explained by current velocity and station. The results suggest that although seasonality is dominant in biofilm BP variation, spatial differences are significant within the seasonal variability. Moreover, current velocity and bottom shear stress related to local geomorphologies such as riffles and pools affect substrate supply rate and biofilm formation processes, regulating biofilm BP variation. This study demonstrated different regulatory factors of planktonic and biofilm BP in the middle reaches of a temperate river.

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13

Wisshak, M., B. Berning, J. Jakobsen, and A. Freiwald. "Temperate carbonate production: biodiversity of calcareous epiliths from intertidal to bathyal depths (Azores)." Marine Biodiversity 45, no. 1 (June 7, 2014): 87–112. http://dx.doi.org/10.1007/s12526-014-0231-6.

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14

DeNicola, Dean M., Elvira de Eyto, Alice Wemaere, and Kenneth Irvine. "Production and respiration of epilithic algal communities in Irish lakes of different trophic status." Archiv für Hydrobiologie 157, no. 1 (May 1, 2003): 67–87. http://dx.doi.org/10.1127/0003-9136/2003/0157-0067.

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15

Klumpp, D. W., and A. D. McKinnon. "Temporal and spatial patterns in primary production of a coral-reef epilithic algal community." Journal of Experimental Marine Biology and Ecology 131, no. 1 (October 1989): 1–22. http://dx.doi.org/10.1016/0022-0981(89)90008-7.

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16

Bj�rk-Ramberg, Susanna, and Claes �nell. "Production and chlorophyll concentration of epipelic and epilithic algae in fertilized and nonfertilized subarctic lakes." Hydrobiologia 126, no. 3 (July 1985): 213–19. http://dx.doi.org/10.1007/bf00007498.

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17

Peterson, Bruce J., John E. Hobbie, and Teresa L. Corliss. "Carbon Flow in a Tundra Stream Ecosystem." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 6 (June 1, 1986): 1259–70. http://dx.doi.org/10.1139/f86-156.

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The carbon cycle of the Kuparuk River, a meandering tundra stream, is dominated by inputs of eroding peat and leaching dissolved organic carbon from the tundra. Net production of epilithic algae is about 13 g C∙m−2∙yr−1, an order of magnitude less than inputs of allochthonous particulate organic carbon and two orders of magnitude less than inputs of dissolved organic carbon. The streamwater has a mean total organic carbon concentration of 6.8 mg∙L−1, and the annual export of organic carbon from the watershed is 2–3 t∙km−2∙yr−1; both are similar to the average for temperate streams. However, because of the low primary productivity of tundra vegetation, the export of organic carbon from the watershed via the river is a larger fraction (2–6%) of the total watershed net primary production than the 0.1–0.4% usually found for temperate rivers.

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18

Beazley, Melanie J., Richard D. Rickman, Debra K. Ingram, Thomas W. Boutton, and Jon Russ. "Natural Abundances of Carbon Isotopes (14C, 13C) in Lichens and Calcium Oxalate Pruina: Implications for Archaeological and Paleoenvironmental Studies." Radiocarbon 44, no. 3 (2002): 675–83. http://dx.doi.org/10.1017/s0033822200032124.

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Radiocarbon ages of calcium oxalate that occurs naturally on rock surfaces have been used recently in archaeological and paleoenvironmental studies. Oxalate rock coatings are found globally, with most appearing to be residues from epilithic lichens. To explore the source(s) of carbon used by these organisms for the production of oxalate we measured the natural abundances of 14C and 13C in 5 oxalate-producing lichen species, 3 growing on limestone in southwestern Texas and 2 on sandstone in Arkansas. We also examined the distribution of the isotopes between the calcium oxalate and lichen tissues by separating these components and measuring the 13C/C independently. The results demonstrate that the limestone species were slightly enriched in 14C, by 1.7%, relative to the sandstone species, which suggests that “dead” carbon from the limestone substrate does not constitute a significant source of carbon for the production of oxalate. The calcium oxalate produced by the lichens is also enriched in 13C by 6.5% compared to the lichen tissues, demonstrating that there is a large carbon isotope discrimination during oxalate biosynthesis. These results support the reliability of 14C ages of calcium oxalate rock coatings used for archaeological and paleoclimate studies.

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19

PAWLIK-SKOWROŃSKA, Barbara, O. William PURVIS, Jacek PIRSZEL, and Tadeusz SKOWROŃSKI. "Cellular mechanisms of Cu-tolerance in the epilithic lichen Lecanora polytropa growing at a copper mine." Lichenologist 38, no. 3 (May 2006): 267–75. http://dx.doi.org/10.1017/s0024282906005330.

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Cellular responses to copper stress were investigated for the first time in a saxicolous lichen species, Lecanora polytropa (Hoffm.) Rabenh. Bright blue-green apothecia accumulated up to 1·3% Cu on a dry weight basis (205 μ mol Cu g−1), c. 50% in an exchangeable form. A bright turquoise-blue layer extended beneath the hymenium into the medulla, above and between a dentate photobiont layer. Oxalic (1·88 μ mol g−1), citric (0·83 μ mol g−1) and lower concentrations of malic (0·45 μ mol g−1) acids were determined by GC/MS analysis. Short-term exposure to high Cu2+ concentrations (40 and 400 μ mol g−1) under non-complexing conditions caused a dose-dependent decrease in chlorophyll a content; chlorophyll b and total carotenoid contents remained constant. The phaeophytinization quotient remained unchanged during Cu2+ exposure. Analysis of thiol peptides confirmed glutathione was reduced (GSH) in native L. polytropa (0·538 μ mol g−1), and phytochelatins (PC2 and PC3) oxidised. Short-term exposure to 40 μ mol g−1 Cu2+ oxidised c. 28% of the glutathione pool; oxidised phytochelatin concentrations remained unchanged. This is the first report of phytochelatin production and thiol peptide status in a crustose lichen. These represent two possible detoxification mechanisms in this Cu-tolerant species. Copper complexation by low molecular mass organic acids and non-protein thiols do not entirely account for its tolerance.

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20

Shamsudin, Lokman, and Michael A. Sleigh. "Seasonal changes in composition and biomass of epilithic algal floras of a chalk stream and a soft water stream with estimates of production." Hydrobiologia 273, no. 3 (January 1994): 131–46. http://dx.doi.org/10.1007/bf00005637.

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21

Wisshak, M., A. Form, J. Jakobsen, and A. Freiwald. "Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores)." Biogeosciences 7, no. 8 (August 13, 2010): 2379–96. http://dx.doi.org/10.5194/bg-7-2379-2010.

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Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate-production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out in the southern Faial Channel to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on down-facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on down-facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

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22

Wisshak, M., A. Form, J. Jakobsen, and A. Freiwald. "Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores, N-Atlantic)." Biogeosciences Discussions 7, no. 3 (May 6, 2010): 3297–333. http://dx.doi.org/10.5194/bgd-7-3297-2010.

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Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and with tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on downward facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on downward facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

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23

LANGE, Otto L., and T. G. Allan GREEN. "Diel and seasonal courses of ambient carbon dioxide concentration and their effect on productivity of the epilithic lichen Lecanora muralis in a temperate, suburban habitat." Lichenologist 40, no. 05 (August 26, 2008): 449–62. http://dx.doi.org/10.1017/s0024282908007676.

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Abstract:Ambient CO2 concentration (together with CO2 exchange and microclimate) was recorded every 30 min for 15 months for Lecanora muralis growing in the Botanical Garden Würzburg (Germany, northern Bavaria), a habitat on the outskirts of the city. Annual mean CO2 was around 17 ppm higher than the global average reported for the time of measurement (361 ppm; 1995/96), and daily values ranged from 317 to 490 ppm. Diel courses of CO2 could be classified into three different types. Type A, when CO2 levels rose overnight and then fell strongly to below global levels during the day, which predominated in the summer (about 75 of days); Type B, irregular diel courses occurred during all seasons with often very rapid changes apparently due to advective CO2 transport; Type C, CO2 concentration was typically almost stable at generally between c. 330 and 430 ppm which predominated in the winter (63 of days).Under controlled conditions, CO2 saturation of net photosynthesis (NP) of L. muralis at optimal hydration and light occurred at around 1000 ppm. NP was also affected by low CO2 at limiting light and thallus water contents. Based upon these data, we estimated the improvement of NP of L. muralis due to transient increase of ambient CO2 (as compared with the global average) for one selected combination of environmental factors (nocturnal dew or frost). This combination is an important source of water for the lichen, resulting in 40 of its annual production and, especially in these situations, photosynthesis was increased by high ambient CO2 in the early morning under prevailing Type A conditions. After dew activation, light compensation point of NP occurred at an average concentration of 413 ppm and diel maxima of NP at 402 ppm. This allows a rough estimate that the transiently elevated CO2 increased the photosynthetic gain of the lichen after dew of 7, or an improvement to its annual carbon balance of about 3. Conditions, especially interrelationships between lichen hydration, light and CO2 are so complex that we are not yet able to extend our estimates to other environmental situations of photosynthetic activity of L. muralis.

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Roik, Anna, Till Röthig, Claudia Pogoreutz, Vincent Saderne, and Christian R. Voolstra. "Coral reef carbonate budgets and ecological drivers in the central Red Sea – a naturally high temperature and high total alkalinity environment." Biogeosciences 15, no. 20 (October 26, 2018): 6277–96. http://dx.doi.org/10.5194/bg-15-6277-2018.

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Abstract. The structural framework provided by corals is crucial for reef ecosystem function and services, but high seawater temperatures can be detrimental to the calcification capacity of reef-building organisms. The Red Sea is very warm, but total alkalinity (TA) is naturally high and beneficial for reef accretion. To date, we know little about how such detrimental and beneficial abiotic factors affect each other and the balance between calcification and erosion on Red Sea coral reefs, i.e., overall reef growth, in this unique ocean basin. To provide estimates of present-day reef growth dynamics in the central Red Sea, we measured two metrics of reef growth, i.e., in situ net-accretion/-erosion rates (Gnet) determined by deployment of limestone blocks and ecosystem-scale carbonate budgets (Gbudget), along a cross-shelf gradient (25 km, encompassing nearshore, midshore, and offshore reefs). Along this gradient, we assessed multiple abiotic (i.e., temperature, salinity, diurnal pH fluctuation, inorganic nutrients, and TA) and biotic (i.e., calcifier and epilithic bioeroder communities) variables. Both reef growth metrics revealed similar patterns from nearshore to offshore: net-erosive, neutral, and net-accretion states. The average cross-shelf Gbudget was 0.66 kg CaCO3 m−2 yr−1, with the highest budget of 2.44 kg CaCO3 m−2 yr−1 measured in the offshore reef. These data are comparable to the contemporary Gbudgets from the western Atlantic and Indian oceans, but lie well below “optimal reef production” (5–10 kg CaCO3 m−2 yr−1) and below maxima recently recorded in remote high coral cover reef sites. However, the erosive forces observed in the Red Sea nearshore reef contributed less than observed elsewhere. A higher TA accompanied reef growth across the shelf gradient, whereas stronger diurnal pH fluctuations were associated with negative carbonate budgets. Noteworthy for this oligotrophic region was the positive effect of phosphate, which is a central micronutrient for reef building corals. While parrotfish contributed substantially to bioerosion, our dataset also highlights coralline algae as important local reef builders. Altogether, our study establishes a baseline for reef growth in the central Red Sea that should be useful in assessing trajectories of reef growth capacity under current and future ocean scenarios.

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25

Monti, Dominique, Cedric Hubas, Xavier Lourenço, Farid Begarin, Alexandre Haouisée, Laurence Romana, Estelle Lefrançois, et al. "Physical properties of epilithic river biofilm as a new lead to perform pollution bioassessments in overseas territories." Scientific Reports 10, no. 1 (October 14, 2020). http://dx.doi.org/10.1038/s41598-020-73948-7.

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Abstract Chlordecone (CLD) levels measured in the rivers of the French West Indies were among the highest values detected worldwide in freshwater ecosystems, and its contamination is recognised as a severe health, environmental, agricultural, economic, and social issue. In these tropical volcanic islands, rivers show strong originalities as simplified food webs, or numerous amphidromous migrating species, making the bioindication of contaminations a difficult issue. The objective of this study was to search for biological responses to CLD pollution in a spatially fixed and long-lasting component of the rivers in the West Indies: the epilithic biofilm. Physical properties were investigated through complementary analyses: friction, viscosity as well as surface adhesion were analyzed and coupled with measures of biofilm carbon content and exopolymeric substance (EPS) production. Our results have pointed out a mesoscale chemical and physical reactivity of the biofilm that can be correlated with CLD contamination. We were able to demonstrate that epilithic biofilm physical properties can effectively be used to infer freshwater environmental quality of French Antilles rivers. The friction coefficient is reactive to contamination and well correlated to carbon content and EPS production. Monitoring biofilm physical properties could offer many advantages to potential users in terms of effectiveness and ease of use, rather than more complex or time-consuming analyses.

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Grishkan, Isabella, and Marina Temina. "Basaltic stones with epilithic lichens as a novel substrate for an osmotolerant fungus, Aspergillus glaucus." Acta Mycologica 52, no. 1 (July 3, 2017). http://dx.doi.org/10.5586/am.1091.

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Aspergillus glaucus is a fungus able to tolerate low water activity of the environment. Its dense growth and sporulation were found on basaltic stones with epilithic lichens after 14 years of storage at a temperature of 4–7°C and relative humidity of 14–18%. Dust and soil particles deposited on the lichen thalli and dissolved in the water condensed on the stones during the storage period, apparently served as a nutrient source for the fungus. Probably, strongly xeric water regime on basaltic stones suitable for A. glaucus did not allow mesophilic fungi to develop and prevented the xerotolerant fungus from competition with other microfungi for nutrient sources. It is also possible that specific cellular mechanism associated with the production of chaotropic compounds (such as glycerol) supported germination and development of A. glaucus at low temperatures, which were considered non-optimal for the fungus.

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27

Ghazay, Alotaibi, and Bukhari Mamdouh. "Characterization and Evaluation of Biofilm Formation by Klebsiella pneumonia MBB9 Isolated from Epilithic Biofilms of the Porter Brook River, Sheffield." Edelweiss Chemical Science Journal, August 4, 2021, 14–24. http://dx.doi.org/10.33805/2690-2613.120.

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Microbes generally attach to surfaces and produce an Extracellular Polymeric Substance (EPS) matrix. The exopolysaccharide production plays a role in biofilm protection against environmental stress factors. Biofilm-forming bacteria exhibit different physiological properties in their response to environmental influences compared with their planktonic counterparts. This study aimed to investigate the impact of changing the concentrations of glucose, peptone, and yeast extract and environmental parameters, such as temperature, pH, anaerobic conditions, osmotic stresses, and growth media on biofilm formation by K. pneumonia MBB9 recovered from river-stones collected from the Porter Brook, Sheffield using crystal violet and resazurin assays in microtiter plates. The different concentrations of glucose (0.25, 0.5 and 1 g L-1), peptone (0.25, 0.5 and 1 g L-1) and yeast extract (0.25, 0.5 and 1 g L-1) as carbon and nitrogen sources found to have an impact on biofilm formation by K. pneumonia MBB9. The greatest biomass level being at 0.25 g L-1 for glucose whereas the density of biofilm increased significantly with increasing the concentration of peptone and yeast extract until 1 g L-1 of peptone and yeast extract, suggesting that higher levels of peptone and yeast extract can be beneficial for biofilm formation by K. pneumonia MBB9 in microtiter plates. The amount of biofilm was high at pH 4.5 and 0.6% NaCl; however, the significant reduction at pH 10.5 and 10.6% NaCl could be as a result of the slow growth under higher NaCl concentrations and highly alkaline condition. High-density biofilm produced at 40 °C; however, a temperature of 50 °C reduced the amount of biofilm by K. pneumonia MBB9, suggesting that more extreme temperatures might affect the formation of biofilm by inhibiting growth. Besides, biofilm production under anaerobic conditions was significantly lower (83% less) than under aerobic environments. Klebsiella pneumonia MBB9 possessed a high capacity to form biofilms on the surface of glass slide coupons.

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Journal articles on the topic 'Epilithon production'

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