Journal articles: 'Diatoms Victoria'

1

Chessman, BC. "Phytoplankton of the La Trobe River, Victoria." Marine and Freshwater Research 36, no. 1 (1985): 115. http://dx.doi.org/10.1071/mf9850115.

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Phytoplankton was sampled on a monthly basis for 1 year at five stations on the La Trobe River in Gippsland, Victoria. In the upper, mostly forested, reaches of the river, chlorophyll a concentrations and cell densities were uniformly very low, and the dominant algae were detached benthic diatoms and flagellated species. In the plains section of the river, downstream of an impoundment (Lake Narracan), spring and autumn blooms occurred, with a marked reduction in abundance in midsummer and midwinter. The lowland planktonic flora was dominated by centric diatoms, particularly Melosira distans in autumn and Skeletonema potamos in spring.

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Triest, Ludwig, Henri Lung’ayia, George Ndiritu, and Abebe Beyene. "Epilithic diatoms as indicators in tropical African rivers (Lake Victoria catchment)." Hydrobiologia 695, no. 1 (June 22, 2012): 343–60. http://dx.doi.org/10.1007/s10750-012-1201-2.

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Currie, BR, and RB Johns. "Lipids as indicators of the origin of organic matter in fine marine particulate matter." Marine and Freshwater Research 39, no. 4 (1988): 371. http://dx.doi.org/10.1071/mf9880371.

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The lipid compositions of fine particulate matter (<35 �m diameter) have been analysed from two temperate sites (Western Port Bay, WPB, and Corner Inlet, CI, Victoria) and two tropical sites (Bowling Green Bay, BGB, and Lizard Island Lagoon, LIL, North Queensland) in the Australian coastal zone. Identification of lipid biomarker molecules (especially fatty acids, fatty alcohols and sterols) has, in conjunction with microscopy, enabled identification and, in some instances, quantification of a range of biological inputs. Estimated contributions of biomass to total particulate mass in the temperate samples were: seagrass detritus (~10-15%) > bacteria (~34%) > live diatoms (≤ 1%). Similar estimations for the tropical samples were: BGB, bacteria (- 1%) > live diatoms (< 1%); and LIL, bacteria (~20-30%) > copepod detritus (≥ 1%) > live diatoms (< 1 %). Biomarkers also indicated the presence of coral mucus and a distinctive bacterial chemotype, possessing branched chain alcohols, in the LIL sample.

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Yule, C. "Comparison of the dietary habits of six species of Dinotoperla (Plecoptera : Gripopterygidae) in Victoria." Marine and Freshwater Research 37, no. 2 (1986): 121. http://dx.doi.org/10.1071/mf9860121.

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The dietary habits of six species of Dinotoperla were determined by field and laboratory observations, nymphal gut analysis, and examination of mouthparts. All the species (D. bassae, D. brevipennis, D. christinae, D. eucumbene, D. fontana and D. thwaitesi) could be classified as herbivore-detritivores, and in each there was a shift from a diet primarily of fine particulate matter to a more polyphagous habit with increasing nymphal size. The diets of the six species were similar, consisting of diatoms, filamentous green algae (except in D. eucumbene), fupgal hyphae, fine particulate matter and vascular plant tissue. However, differences were observed in the nutritional quality of their diets in terms of protein and calorific content. The two smallest species studied, D. brevipennis and D. eucumbene, consumed mostly fine particulate matter-the least nutritionally valuable of available food items (apart from wood, which was not eaten by Dinotoperla nymphs). D. eucumbene was also the slowest growing of the six species. The fastest-growing species, D. bassae, was also the largest, and the nymphs of this species consumed the highest-quality diet, eating large amounts of filamentous green algae and diatoms.

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Dinelka Thilakarathne and Gayan Hirimuthugoda. "Can the Sri Lankan endemic-endangered fish Labeo fisheri (Teleostei: Cyprinidae) adapt to a new habitat?" Journal of Threatened Taxa 14, no. 8 (August 26, 2022): 21579–87. http://dx.doi.org/10.11609/jott.7621.14.8.21579-21587.

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Labeo fisheri is an endemic and endangered freshwater fish of Sri Lanka. Mainly restricted to the upper reaches of the Mahaweli River basin, it has been previously reported living in deep rapids and among large rocks and boulders. An accidental record of a Labeo fisheri specimen from Victoria Reservoir led us to further study this habitat during the period from January to August 2017. This study was carried out to confirm the presence of a population of Labeo fisheri within the Victoria Reservoir and report its new habitat type in deep stagnant waters. We further investigated the food habits by analyzing the gut contents of L. fisheri in the Victoria Reservoir. Seven individuals were recorded from fishermen’s gill net catch in three fish landing sites along Victoria Reservoir, with an average total length of 24.80 ± 4.30 cm, average standard length of 19.70 ± 3.86 cm and average body weight of 197.69 ± 107.12 g. Based on gut content analysis, only phytoplankton, especially diatoms and cyanobacteria, were found in the gut of L. fisheri. This new population is facing the direct threat of fishing. Effective conservation measures are doubtful, since a fishery is well established in the Victoria Reservoir and the fishing gear used is not species-specific. More research is necessary to understand the population dynamics of L. fisheri in the Victoria Reservoir. In order to conserve it at this locality, community-based conservation measures are recommended.

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Simiyu, Benard Mucholwa, and Rainer Kurmayer. "Response of planktonic diatoms to eutrophication in Nyanza Gulf of Lake Victoria, Kenya." Limnologica 93 (March 2022): 125958. http://dx.doi.org/10.1016/j.limno.2022.125958.

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Mwanuzi, F., D. K. Rutagemwa, and A. Mathayo. "Sedimentation Status of Lake Victoria: Loading from River Mouth and In-lake Sedimentation." Tanzania Journal of Engineering and Technology 31, no. 1 (June 30, 2008): 88–101. http://dx.doi.org/10.52339/tjet.v31i1.420.

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Lake sediments consist of the input of suspended solids by river discharges, the autochthonous produced particulate matter in the water column and the settled material on the lake bottom. The loading, transport, formation and decay of the sediments entering the Lake Victoria from Tanzanian side was monitored for the period 2000 to 2005. The sedimentation study focused on; quantification of settling fluxes of particulate nutrients and organic carbon at the off-shore(Pelagic) and near-shore(Littoral) monitoring stations. Monitored data on sedimentation rate and settling velocities has been sampled and analysed in the period November 2000 to March 2005. The mean sedimentation rate at littoral stations for total particulate phosphorous (TPP) was about twice as compared to pelagic stations. The same situation was observed for total particulate carbon (TPC), however, total particulate silica did not show a clear pattern of variability between littoral and pelagic stations though there was a general tendency of decreasing towards the pelagic stations. Mean value for TPC /TPP sedimentation rate ratio was 117.61 for littoral and 90.74 for pelagic stations respectively compared to TBSi/TPP which was 3.15 for littoral and 2.10 for pelagic stations. The results show that sedimentation rates are highest at the littoral stations compared to pelagic stations. The differences in settling velocities indicate that the settling material consists dead and living material with a contribution of diatoms. The stoichiometriccomposition of the settling material indicates nitrogen limitation and a non-dominance of diatoms.

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Webster-Brown, J., M. Gall, J. Gibson, S. Wood, and I. Hawes. "The biogeochemistry of meltwater habitats in the Darwin Glacier region (80°S), Victoria Land, Antarctica." Antarctic Science 22, no. 6 (December 2010): 646–61. http://dx.doi.org/10.1017/s0954102010000787.

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AbstractMeltwater habitats in the Darwin Glacier region, Victoria Land (80°S), were sampled in December 2007 and January 2009 to characterize their microbial and metazoan ecology, nutrient status and geochemistry. Targeted areas included terrestrial ponds of the Grant Valley, Lake Wellman, Tentacle Ridge and Diamond Hill, and supraglacial ponds and cryoconite holes of the lower Darwin Glacier. Geochemistry ranged from Na-Cl dominated terrestrial ponds to Na-HCO3dominated, dilute supraglacial ponds and cryoconites. All showed the nitrate enrichment typical of inland ponds of Victoria Land (up to 13 g.l-1NO3-N), with some precipitating nitratine (NaNO3) salt. Elevated pH indicated ongoing photosynthetic processes. Benthic microbial mats were thin and poorly developed, dominated by oscillatoriacean cyanobacteria. Nitrogen-fixing genera were generally absent and diatoms were rare. A large (20 μm long)Cyanothecespecies was the most abundant cyanobacterium in the water and in sediments of the cryoconites. DNA finger-printing identified distinct differences in cyanobacterial and bacterial community structure between the cryoconites, terrestrial ponds and ponds on glacial margins. Eleven metazoan species were identified, with rotifers being the most abundant. Pond substrate (terrestrial rock, ice-cored moraine or supraglacial ice) proved to be a more significant influence on biogeochemistry than other aspects of geography or climatic conditions.

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Kvale, Karin, David P. Keller, Wolfgang Koeve, Katrin J. Meissner, Christopher J. Somes, Wanxuan Yao, and Andreas Oschlies. "Explicit silicate cycling in the Kiel Marine Biogeochemistry Model version 3 (KMBM3) embedded in the UVic ESCM version 2.9." Geoscientific Model Development 14, no. 12 (November 30, 2021): 7255–85. http://dx.doi.org/10.5194/gmd-14-7255-2021.

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Abstract. We describe and test a new model of biological marine silicate cycling, implemented in the Kiel Marine Biogeochemical Model version 3 (KMBM3), embedded in the University of Victoria Earth System Climate Model (UVic ESCM) version 2.9. This new model adds diatoms, which are a key component of the biological carbon pump, to an existing ecosystem model. This new model combines previously published parameterizations of a diatom functional type, opal production and export with a novel, temperature-dependent dissolution scheme. Modelled steady-state biogeochemical rates, carbon and nutrient distributions are similar to those found in previous model versions. The new model performs well against independent ocean biogeochemical indicators and captures the large-scale features of the marine silica cycle to a degree comparable to similar Earth system models. Furthermore, it is computationally efficient, allowing both fully coupled, long-timescale transient simulations and “offline” transport matrix spinups. We assess the fully coupled model against modern ocean observations, the historical record starting from 1960 and a business-as-usual atmospheric CO2 forcing to the year 2300. The model simulates a global decline in net primary production (NPP) of 1.4 % having occurred since the 1960s, with the strongest declines in the tropics, northern midlatitudes and Southern Ocean. The simulated global decline in NPP reverses after the year 2100 (forced by the extended RCP8.5 CO2 concentration scenario), and NPP returns to 98 % of the pre-industrial rate by 2300. This recovery is dominated by increasing primary production in the Southern Ocean, mostly by calcifying phytoplankton. Large increases in calcifying phytoplankton in the Southern Ocean offset a decline in the low latitudes, producing a global net calcite export in 2300 that varies only slightly from pre-industrial rates. Diatom distribution moves southward in our simulations, following the receding Antarctic ice front, but diatoms are outcompeted by calcifiers across most of their pre-industrial Southern Ocean habitat. Global opal export production thus drops to 75 % of its pre-industrial value by 2300. Model nutrients such as phosphate, silicate and nitrate build up along the Southern Ocean particle export pathway, but dissolved iron (for which ocean sources are held constant) increases in the upper ocean. This different behaviour of iron is attributed to a reduction of low-latitude NPP (and consequently, a reduction in both uptake and export and particle, including calcite scavenging), an increase in seawater temperatures (raising the solubility of particulate iron) and stratification that “traps” the iron near the surface. These results are meant to serve as a baseline for sensitivity assessments to be undertaken with this model in the future.

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10

Novis, Phil M., Jackie Aislabie, Susan Turner, and Malcolm McLeod. "Chlorophyta, Xanthophyceae and Cyanobacteria in Wright Valley, Antarctica." Antarctic Science 27, no. 5 (April 22, 2015): 439–54. http://dx.doi.org/10.1017/s0954102015000164.

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AbstractWright Valley, Victoria Land contains numerous aquatic habitats suitable for the growth of algae in summer. Excepting diatoms and lichen phycobionts, algal diversity and distribution in the valley was documented. Using cultures and environmental cloning eight cyanobacterial and 14 eukaryotic species were revealed. The cyanobacterium Microcoleus vaginatus and the chlorophycean Chlorococcum sp. 1 were the most common, both occurring in more than one habitat (ponds, soils or streams). Ponds harboured the most diverse communities. Habitat specialization was rare. Chlamydomonads were not found outside ponds, but species capable of zoospore production were able to colonize ponds and soils. Nostocalean cyanobacteria were not detected. Results suggest dispersal within and between valleys, with little evidence of Antarctic endemism. All but one cyanobacterium with similar internally transcribed spacer (ITS) length to clones from Miers Valley proved to be different species when 16S rRNA gene sequences were also considered; thus, ITS length is unreliable for assessing identity and biogeography of these cyanobacteria. Comparison with a 454 16S rRNA gene soil dataset from Wright Valley indicated the occurrence of only one of the cyanobacterial species, the distribution of which may be limited by salinity.

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11

Verbers, Anja L. L. M., and Volkmar Damm. "Morphology and late Cenozoic (<5 Ma) glacial history of the area between David and Mawson Glaciers, Victoria Land, Antarctica." Annals of Glaciology 20 (1994): 55–60. http://dx.doi.org/10.3189/1994aog20-1-55-60.

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Glacio-geological field work and radar ice-thickness sounding were carried out in the area between David and Mawson Glaciers. A subglacial topographic map has been compiled from radio-echo-sounding data. The northern part of this map shows that the trench of David Glacier reaches a depth of more than 1000 m below sea level. The area south of David Glacier comprises a landscape of nunatak clusters dissected by glaciated valleys with ice thicknesses as much as 800 m. Subglacial cirques occur at the outer margins of the nunatak clusters. A model for the regional glacial history is proposed. It starts with a major deglaciation in the Pliocene, which results in marine transgression in basins west of the Transantarctic Mountains. During the late Pliocene, the ice advanced towards the northeast, depositing a thin layer of (Sirius Group) till containing reworked mid-Pliocene marine diatoms. Due to accelerated mountain uplift, the ice cut iIlto the pre-Pliocene peneplain, eroding broad valleys. A period of ice-sheet retreat followed to expose a landscape of large nunataks separated by wide valleys. During this period, local cirque glaciation occurred. When the ice sheet advanced again, another phase of uplift forced the glaciers to cut deeper into the valleys. Probably since the Last Glacial Maximum the ice surface has lowered by about 100 m.

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12

Verbers, Anja L. L. M., and Volkmar Damm. "Morphology and late Cenozoic (<5 Ma) glacial history of the area between David and Mawson Glaciers, Victoria Land, Antarctica." Annals of Glaciology 20 (1994): 55–60. http://dx.doi.org/10.1017/s0260305500016232.

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Glacio-geological field work and radar ice-thickness sounding were carried out in the area between David and Mawson Glaciers. A subglacial topographic map has been compiled from radio-echo-sounding data. The northern part of this map shows that the trench of David Glacier reaches a depth of more than 1000 m below sea level. The area south of David Glacier comprises a landscape of nunatak clusters dissected by glaciated valleys with ice thicknesses as much as 800 m. Subglacial cirques occur at the outer margins of the nunatak clusters. A model for the regional glacial history is proposed. It starts with a major deglaciation in the Pliocene, which results in marine transgression in basins west of the Transantarctic Mountains. During the late Pliocene, the ice advanced towards the northeast, depositing a thin layer of (Sirius Group) till containing reworked mid-Pliocene marine diatoms. Due to accelerated mountain uplift, the ice cut iIlto the pre-Pliocene peneplain, eroding broad valleys. A period of ice-sheet retreat followed to expose a landscape of large nunataks separated by wide valleys. During this period, local cirque glaciation occurred. When the ice sheet advanced again, another phase of uplift forced the glaciers to cut deeper into the valleys. Probably since the Last Glacial Maximum the ice surface has lowered by about 100 m.

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13

Pautova, Larisa A., Vladimir A. Silkin, Marina D. Kravchishina, Valeriy G. Yakubenko, and Anna L. Chultsova. "Summer phytoplankton of the northern Barents Sea (75–80º N)." Hydrosphere Еcology (Экология гидросферы), no. 2(4) (2019): 8–19. http://dx.doi.org/10.33624/2587-9367-2019-2(4)-8-19.

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The structure of the summer planktonic communities of the Northern part of the Barents sea in the first half of August 2017 were studied. In the sea-ice melting area, the average phytoplankton biomass producing upper 50-meter layer of water reached values levels of eutrophic waters (up to 2.1 g/m3). Phytoplankton was presented by diatoms of the genera Thalassiosira and Eucampia. Maximum biomass recorded at depths of 22–52 m, the absolute maximum biomass community (5,0 g/m3) marked on the horizon of 45 m (station 5558), located at the outlet of the deep trench Franz Victoria near the West coast of the archipelago Franz Josef Land. In ice-free waters, phytoplankton abundance was low, and the weighted average biomass (8.0 mg/m3 – 123.1 mg/m3) corresponded to oligotrophic waters and lower mesotrophic waters. In the upper layers of the water population abundance was dominated by small flagellates and picoplankton from, biomass – Arctic dinoflagellates (Gymnodinium spp.) and cold Atlantic complexes (Gyrodinium lachryma, Alexandrium tamarense, Dinophysis norvegica). The proportion of Atlantic species in phytoplankton reached 75%. The representatives of warm-water Atlantic complex (Emiliania huxleyi, Rhizosolenia hebetata f. semispina, Ceratium horridum) were recorded up to 80º N, as indicators of the penetration of warm Atlantic waters into the Arctic basin. The presence of oceanic Atlantic species as warm-water and cold systems in the high Arctic indicates the strengthening of processes of “atlantificacion” in the region.

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Stager, J. Curt, Brian Cumming, and Loren Meeker. "A High-Resolution 11,400-Yr Diatom Record from Lake Victoria, East Africa." Quaternary Research 47, no. 1 (January 1997): 81–89. http://dx.doi.org/10.1006/qres.1996.1863.

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AbstractFine-interval (∼30–45 yr) sampling of a core from Lake Victoria's Damba Channel shows that numerous abrupt changes in the lake's diatom assemblages have occurred in response to climatic fluctuations over the past 11,40014C yr. Four distinct climatic phases bounded by sudden transitions are inferred: (1) variably dry ∼11,400–10,000 yr B.P., (2) humid ∼10,000–7200 yr B.P., (3) more seasonal ∼7200–2200 yr B.P., and (4) more arid ∼2200–0 yr B.P., with a dry “Little Ice Age” event ∼600–200 yr B.P. The diatom-inferred paleoclimatic history for northern Lake Victoria closely resembles that inferred from a well-dated pollen record from Pilkington Bay. Spectral analysis of the diatom record reveals strong periodicities including globally distributed ∼2360–2550, ∼1400, ∼1030–1130, and ∼500 cal-yr cycles. Repeated, rapid shifts betweenAulacoseira- andNitzschia-dominated diatom assemblages suggest that post-1960 changes in the lake's phytoplankton communities have had earlier, climate-driven analogs.

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Andama, M., J. B. Lejju, and C. U. Tolo. "Late holocene trends of phytoplankton productivity and anoxia as inferred from diatom and geochemical proxies in Lake Victoria, Eastern Africa." Biogeosciences Discussions 10, no. 11 (November 12, 2013): 17663–82. http://dx.doi.org/10.5194/bgd-10-17663-2013.

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Abstract. Lake Victoria ecosystem has undergone major ecological changes in the recent decades. Sedimentary diatom analysis and Fe / Mn determined by Energy Dispersive X-ray Fluorescence (EDXRF) have provided phytoplankton (diatom) productivity and the resultant anoxia (Fe / Mn) in Lake Victoria at Napoleon Gulf during the late Holocene (1778 cal yr BP (calibrated years before present) to 2008 AD) with radiocarbon dates determined using Accelerator Mass Spectrometry standard method. The results showed that increased total diatom counts in Napoleon Gulf during the late Holocene correspond with increased Fe / Mn ratio (anoxia) in some of the profiles and not in others and in most cases those that correspond correlate very well with increased eutrophication from nitrate input (Total Nitrogen, TN). Therefore slightly increased anoxia not related to increased diatom productivity was recorded in Lake Victoria at Napoleon Gulf from the period 1778 to 1135 cal yr BP. There was slightly increased diatom productivity at Napoleon Gulf from the period 857 to 758 cal yr BP but it did not increase anoxia in the lake. The period 415 cal yr BP to 2008 AD recorded increased anoxia at Napoleon Gulf related to high diatom productivity especially from 415 to 390 cal yr BP and 191 cal yr BP to 2008 AD.

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STANCHEVA, ROSALINA, NATHANIEL V. KRISTAN, WILLIAM B. KRISTAN III, and ROBERT G. SHEATH. "Diatom genus Planothidium (Bacillariophyta) from streams and rivers in California, USA: diversity, distribution and autecology." Phytotaxa 470, no. 1 (November 2, 2020): 1–30. http://dx.doi.org/10.11646/phytotaxa.470.1.1.

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The diatom genus Planothidium from streams and rivers in California was studied by applying the most current species designations. Twenty Planothidium taxa were identified in total, including a previously undescribed species, Planothidium californicum. Extensive light and scanning electron microscopic documentation is provided to support consistent further identification of the taxa for the local stream bioassessment. The most common and abundant species, recorded across the entire state, were P. frequentissimum, P. lanceolatum, P. victorii, P. cryptolanceolatum, P. amphibium, and P. minutissimum. Species ranges and species-weighted averages for the main anthropogenic stressors, i.e. chloride, conductivity, dissolved organic carbon, total nitrogen and total phosphorus were determined for the eleven most common Planothdium taxa. Statistically significant differences among species weighted averages were determined by randomization test. Of these eleven species, P. delicatulum, P. robustum, P. engelbrechtii, P. frequentissimum and P. victorii had the highest weighted averages along the chloride and conductivity gradients. P. potapovae, Planothidium sp. 1, P. amphibium, and P. engelbrechtii had narrow nutrient ranges and lowest weighted averages for total nitrogen and phosphorus, making them significantly different from P. delicatulum which had highest total nitrogen average and from P. minutissimum, associated with highest total phosphorus average level. Given that there were differences in associations with environmental variables between recently described species, it is important to use the new taxonomy when using diatoms in bioassessment work.

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Van De Vijver, Bart, Andy Van Kerckvoorde, and Louis Beyens. "Freshwater and terrestrial moss diatom assemblages of the Cambridge Bay area, Victoria Island (Nunavut, Canada)." Nova Hedwigia 76, no. 1-2 (February 1, 2003): 225–43. http://dx.doi.org/10.1127/0029-5035/2003/0076-0225.

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Gell, Peter A., Ian R. Sluiter, and Jennie Fluin. "Seasonal and interannual variations in diatom assemblages in Murray River connected wetlands in north-west Victoria, Australia." Marine and Freshwater Research 53, no. 6 (2002): 981. http://dx.doi.org/10.1071/mf01021.

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Epipelic diatom assemblages collected from three wetlands connected to the Murray River displayed considerable variation in response to flooding and drying phases. Murray River water input usually generated diatom assemblages dominated by Aulacoseira species. After isolation, the diatom flora of two wetlands shifted to assemblages of small Fragilariaceae forms. Elevated nutrient levels corresponded with the appearance of eutraphentic taxa such as Cyclotella meneghiniana, Eolimna subminuscula, Luticola mutica and Nitzschia palea. Further evapoconcentration induced shifts to taxa tolerant of elevated salinity levels including Amphora coffeaeformis, Navicula incertata, Staurophora salina and Tryblionella hungarica. Ordination analyses reveal a strong chemical control on the diatom taxa present in the wetlands, in accordance with known ecological preferences for salinity and nutrients. The influence of nitrogen and phosphorus concentrations in controlling diatom assemblages was subordinate to salinity once conductivity values exceeded 1400 μS cm–1. The results of such biomonitoring provide a means of interpreting wetland history from fossil assemblages contained in sediment sequences.

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Chessman, BC. "Artificial-substratum periphyton and water quality in the lower La Trobe River, Victoria." Marine and Freshwater Research 36, no. 6 (1985): 855. http://dx.doi.org/10.1071/mf9850855.

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Between February 1975 and March 1977, periphyton from artificial substrata (glass microscope slides) and water samples for physicochemical analysis were obtained from eight sites on the lowland section of the La Trobe River, which flows through agricultural, urban and industrial areas. Total organic matter on the slides, estimated as weight loss on ignition, was usually highest in summer or autumn when river flows were low. However, chlorophyll a densities generally peaked in late winter and spring when nitrate concentrations were high, except at a site upstream of major urban and industrial areas, where a summer-autumn increase occurred. Thermal discharges from major power stations had no obvious effect on chlorophyll abundance, but did appear to substantially influence diatom assemblage composition from late summer to early winter, when river temperatures were highest. Downstream of the Morwell River confluence, diatom assemblages were influenced by a sharp increase in dissolved solids concentration and probably also by the grazing activities of snails (Ferrissia petterdi and Physastra gibbosa). The diatom flora at the most downstream site showed some evidence of recovery from thermal effects.

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Chessman, BC. "Dietary studies of Aquatic insects from two Victorian rivers." Marine and Freshwater Research 37, no. 2 (1986): 129. http://dx.doi.org/10.1071/mf9860129.

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A preliminary assessment of the feeding habits of 127 taxa of pre-imaginal Coleoptera, Diptera, Ephemeroptera, Plecoptera and Trichoptera from the La Trobe and Tanjil Rivers was made from analyses of digestive tract contents and observations of captive specimens. Ultrafine (<50 �n) detritus was the dominant material in gut contents of all five orders, and fine (< 1 mm, > 50 �lm) detritus (mostly leaf and wood fragments), benthic algae (especially diatoms) and remains of invertebrate prey were also important. Bacteria, fungi and planktonic algae were present in minor quantities. Many species were shown to be capable of shredding dead leaves and wood. Dietary diversity was particularly high in the families Elmidae, Chironomidae, Leptophlebiidae, Gripopterygidae and Leptoceridae.

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Chessman, Bruce C., Nina Bate, Peter A. Gell, and Peter Newall. "A diatom species index for bioassessment of Australian rivers." Marine and Freshwater Research 58, no. 6 (2007): 542. http://dx.doi.org/10.1071/mf06220.

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The Diatom Index for Australian Rivers (DIAR), originally developed at the genus level, was reformulated at the species level with data from diatom sampling of rivers in the Australian Capital Territory, New South Wales, Queensland, South Australia and Victoria. The resulting Diatom Species Index for Australian Rivers (DSIAR) was significantly correlated with the ARCE (Assessment of River Condition, Environment) index developed in the Australian National Land and Water Resources Audit (NLWRA), and with nine of the ARCE’s constituent indices and sub-indices, across 395 river reaches in south-eastern Australia. These correlations were generally stronger than those shown by the biological index that was used to assess river condition in the NLWRA, the ARCB (Assessment of River Condition, Biota) index based on macroinvertebrates and the Australian River Assessment System (AUSRIVAS). At a finer spatial scale, DSIAR was strongly and significantly correlated with measures of catchment urbanisation for streams in the eastern suburbs of Melbourne, Victoria. DSIAR scores across south-eastern Australia bore little relationship to the latitude, longitude or altitude of sampling sites, suggesting that DSIAR is not greatly affected by macro-geographical position. In addition, DSIAR scores did not vary greatly among small-scale hydraulic environments within a site. DSIAR appears to have potential as a broad-scale indicator of human influences on Australian rivers, especially the effects of agricultural and urban land use, and also for impact studies at a local scale. Further evaluation is warranted to test the sensitivity of the index to natural variables such as catchment geology, and to assess its performance in northern, western and inland Australia.

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Stager, J. Curt, Brian F. Cumming, and L. David Meeker. "A 10,000-year high-resolution diatom record from Pilkington Bay, Lake Victoria, East Africa." Quaternary Research 59, no. 2 (March 2003): 172–81. http://dx.doi.org/10.1016/s0033-5894(03)00008-5.

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AbstractA new diatom record from Lake Victoria’s Pilkington Bay, subsampled at 21- to 25-year intervals and supported by 20 AMS dates, reveals a ∼10,000 calendar year environmental history that is supported by published diatom and pollen data from two nearby sites. With their chronologies adjusted here to account for newly documented ancient carbon effects in the lake, these three records provide a coherent, finely resolved reconstruction of Holocene climate change in equatorial East Africa. After an insolation-induced rainfall maximum ca. 8800–8300 cal yr B.P., precipitation became more seasonal and decreased abruptly ca. 8200 and 5700 yr B.P. in apparent association with northern deglaciation events. Century-scale rainfall increases occurred ca. 8500, 7000, 5800, and 4000 yr B.P. Conditions after 2700 yr B.P. were generally similar to those of today, but major droughts occurred ca. 1200–600 yr B.P. during Europe’s Medieval Warm Period.

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Haynes, D., P. Rayment, K. Raynes, and PRL Mosse. "Laboratory-based investigation into the potential for algal proliferation in Lake Coleman, Victoria." Marine and Freshwater Research 45, no. 4 (1994): 625. http://dx.doi.org/10.1071/mf9940625.

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Lake Coleman received a discharge of highly coloured, treated pulp and paper mill effluent and domestic and industrial effluent from 1958 until the latter part of 1992. The colour of the lake waters is likely to become less intense following cessation of the discharge and this may affect the potential for algal growth. The estuarine diatom Phaeodactylum tricornutum was cultured in a range of concentrations of Lake Coleman water with and without pre-exposure to nutrient-rich Lake Coleman sediments. Under laboratory conditions, growth of P. tricornutum was significantly enhanced in Lake Coleman water compared with cultures grown in water collected from an adjacent unpolluted lake. Growth was further enhanced in solutions with additional pre-exposure to Lake Coleman sediments. Growth enhancement exhibited a linear relationship to solution orthophosphate concentrations. When the diatom was cultured under a range of light intensities produced by a range of dilutions of Lake Coleman water, growth was significantly reduced by high colour intensity. The possibility exists, therefore, for enhanced algal proliferation in Lake Coleman following cessation of effluent discharge.

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Gell, Peter A. "The Development of a Diatom Database for Inferring Lake Salinity, Western Victoria, Australia: Towards a Quantitative Approach for Reconstructing Past Climates." Australian Journal of Botany 45, no. 3 (1997): 389. http://dx.doi.org/10.1071/bt96036.

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The development of a modern data set of 156 diatom samples from salt lakes has provided evidence of the tolerance of a large number of taxa to the salinity of lake waters. Thirty taxa have been recorded from 30 or more samples and so have been well characterised. A further 42 taxa have been recorded from 10 or more samples. The lakes sampled range in salinity from the freshwater–oligosaline boundary to well into the hypersaline range, so the upper and lower salinity tolerance limits of many species were investigated. Canonical correspondence analysis of the data set showed that salinity was the most important of the tested parameters influencing the diatom assemblages in the samples. Randomisation tests have provided correlation values between measured and predicted salinity comparable with those gained from other major salt lake diatom data sets, suggesting that this set is a good predictor of lake salinity.

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Jones, D., and J. Reid. "A Comparison of Photomicrographs Imaged Through a Late 18th C. Thomas Ribright, Cuff-Type, Brass Microscope and a Modern Olympus Optical Microscope." Microscopy Today 14, no. 2 (March 2006): 38–43. http://dx.doi.org/10.1017/s1551929500055358.

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In 1967, Bradbury published a detailed study of the optical properties of early, compound microscopes using modern photo micrographic techniques. This was followed by Bracegirdle's studies on the performance of 17th and 18th C. microscopes and later by Jones's comparative study of a Victorian microscope with an 18th C. Cuff-type microscope, signed ‘ Dollond ’. On the suggestion of the late Dr. S. Bradbury (personal communication), the present study on the assessment of a Ribright microscope includes photomicrographs of specimens in slides similar to the ones he used, i.e. a blow-fly proboscis and diatoms.

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Cocquyt, Christine, Wolf-Henning Kusber, and Regine Jahn. "Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)." Afrika Focus 21, no. 1 (February 15, 2008): 65–75. http://dx.doi.org/10.1163/2031356x-02101006.

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At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See- und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these microalgae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org.

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Stager, J. Curt, Robert E. Hecky, Dustin Grzesik, Brian F. Cumming, and Hedy Kling. "Diatom evidence for the timing and causes of eutrophication in Lake Victoria, East Africa." Hydrobiologia 636, no. 1 (November 9, 2009): 463–78. http://dx.doi.org/10.1007/s10750-009-9974-7.

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Nakintu, J., and J. B. Lejju. "A 10000 14C yr diatom record from Napoleon Gulf and Sango Bay, Lake Victoria." Quaternary International 404 (June 2016): 180–81. http://dx.doi.org/10.1016/j.quaint.2015.08.114.

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Sonneman, Jason A., Christopher J. Walsh, Peter F. Breen, and Andrew K. Sharpe. "Effects of urbanization on streams of the Melbourne region, Victoria, Australia. II. Benthic diatom communities." Freshwater Biology 46, no. 4 (April 28, 2001): 553–65. http://dx.doi.org/10.1046/j.1365-2427.2001.00689.x.

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Berra, TM, A. Campbell, and PD Jackson. "Diet of the Australian grayling, Prototroctes maraena Gnnther (Salmoniformes : Prototroctidae), with notes on the occurence of a trematode parasite and black peritoneum." Marine and Freshwater Research 38, no. 5 (1987): 661. http://dx.doi.org/10.1071/mf9870661.

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The diet of the Australian grayling was studied based upon an examination of the stomach and intestinal contents of 558 fish taken from the Tambo River, Victoria, throughout 1979. The most frequent food items were the immature stages of aquatic insects such as chironomids, trichopterans, and ephemeropterans, gastropods and abundant plant material in the form of a diatom/organic matrix that occurred in 83% of the stomachs. It is speculated that the grayling's black peritoneum is related to the presence of plant matter in the diet. A total of 120 different taxa was recorded but only 23 taxa occurred in 5% or more of the stomachs. Most stomachs were three-quarters full and mean monthly fullness varied little throughout the year. There was little dietary overlap between summer (when the diatom/organic matrix was of relatively low importance) and the other seasons in all size classes examined. There was significant dietary overlap between the size groups for all seasons except summer. Trematode parsites of the family Opecoelidae occurred throughout the gut in 86% of the specimens. The largest fish had the most parasites, and the incidence of infection was consistently high throughout the year.

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Olney, Matthew P., Reed P. Scherer, Steven M. Bohaty, and David M. Harwood. "Eocene–Oligocene paleoecology and the diatom genus Kisseleviella Sheshukova-Poretskaya from the Victoria Land Basin, Antarctica." Marine Micropaleontology 58, no. 1 (December 2005): 56–72. http://dx.doi.org/10.1016/j.marmicro.2005.09.003.

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Winton, V. H. L., G. B. Dunbar, C. B. Atkins, N. A. N. Bertler, B. Delmonte, P. S. Andersson, A. Bowie, and R. Edwards. "The origin of lithogenic sediment in the south-western Ross Sea and implications for iron fertilization." Antarctic Science 28, no. 4 (February 26, 2016): 250–60. http://dx.doi.org/10.1017/s095410201600002x.

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AbstractSummer iron (Fe) fertilization in the Ross Sea has previously been observed in association with diatom productivity, lithogenic particles and excess Fe in the water column. This productivity event occurred during an early breakout of sea ice via katabatic winds, suggesting that aeolian dust could be an important source of lithogenic Fe required for diatom growth in the Ross Sea. Here we investigate the provenance of size-selected dust deposited on sea ice in McMurdo Sound, south-western (SW) Ross Sea. The isotopic signature of McMurdo Sound dust (0.70533<87Sr/86Sr<0.70915 and -1.1<εNd(0)<3.45) confirms that dust is locally sourced from the McMurdo Sound debris bands and comprises a two-component mixture of McMurdo Volcanic Group and southern Victoria Land lithologies. In addition, the provenance of lithogenic sediment trapped in the water column was investigated, and the isotopic signature (εNd(0)=3.9, 87Sr/86Sr=0.70434) is differentiated from long-range transported dust originating from South America and Australia. Elevated lithogenic accumulation rates in deeper sediment traps in the Ross Sea suggest that sinking particles in the water column cannot simply result from dust input at the surface. This discrepancy can be best explained by significant upwelling and remobilization of lithogenic Fe from the sea floor.

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Michelutti, Neal, Anita J. Holtham, Marianne S. V. Douglas, and John P. Smol. "PERIPHYTIC DIATOM ASSEMBLAGES FROM ULTRA-OLIGOTROPHIC AND UV TRANSPARENT LAKES AND PONDS ON VICTORIA ISLAND AND COMPARISONS WITH OTHER DIATOM SURVEYS IN THE CANADIAN ARCTIC1." Journal of Phycology 39, no. 3 (June 2003): 465–80. http://dx.doi.org/10.1046/j.1529-8817.2003.02153.x.

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Stager, J. Curt, Christine Cocquyt, Raymonde Bonnefille, Constanze Weyhenmeyer, and Nicole Bowerman. "A late Holocene paleoclimatic history of Lake Tanganyika, East Africa." Quaternary Research 72, no. 1 (July 2009): 47–56. http://dx.doi.org/10.1016/j.yqres.2009.04.003.

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AbstractA nearshore core (LT03-05) from the north basin of Lake Tanganyika provides diatom, pollen, and sedimentary time series covering the last ca. 3800 yr at 15–36 yr resolution. A chronology supported by 21 AMS dates on terrestrial and lacustrine materials allows us to account for ancient carbon effects on 14C ages and to propose refinements of the region's climatic history. Conditions drier than those of today were followed after ca. 3.30 ka by an overall wetting trend. Several century-scale climate variations were superimposed upon that trend, with exceptionally rainy conditions occurring 1.70–1.40 ka, 1.15–0.90 ka, 0.70–0.55 ka, and 0.35–0.20 ka. Around 0.55–0.35 ka, during the Spörer sunspot minimum, drier conditions developed in the northern Tanganyika basin while more humid conditions were registered at Lakes Victoria and Naivasha. This indicates significant variability in the nature and distribution of near-equatorial rainfall anomalies during much of the Little Ice Age.

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Podritske, Brandi, and Konrad Gajewski. "Diatom community response to multiple scales of Holocene climate variability in a small lake on Victoria Island, NWT, Canada." Quaternary Science Reviews 26, no. 25-28 (December 2007): 3179–96. http://dx.doi.org/10.1016/j.quascirev.2007.06.009.

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Blinn, DW, SL Blinn, and IAE Bayly. "Feeding ecology of Haloniscus earlei chilton, and Oniscoid Isopod living in Athalassic Saline Waters." Marine and Freshwater Research 40, no. 3 (1989): 295. http://dx.doi.org/10.1071/mf9890295.

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Densities of the oniscoid isopod, Haloniscus searlei Chilton, were orders of magnitude higher on solid substrata than on sediment in the athalassic saline waters of Lake Keilambete and Lake Corangamite, Victoria, Australia. The feeding ecology of H. searlei was examined in the laboratory. Three different grazing densities were employed; one was similar to the estimated density of Haloniscus in the field (c. 212 individuals per m² siderite substratum), and the other two were 3 and 5.5 times higher than field densities, respectively. It was concluded that H. searlei was a very effective grazer. After 2 weeks, treatments with the highest grazing density had 2.5 times less periphyton biomass than treatments at the lowest grazing density and over 3-fold less periphyton than ungrazed controls. Estimated consumption-index values for periphyton were 0.206, 0.124, and 0.096 for treatments ranging from low to high grazing densities. Diatom community structure remained the same in all grazing treatments after 2 weeks. The ability of Haloniscus to use Tanytarsus larvae for food was examined. Cannibalism was also noted.

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Passchier, Sandra, Anja L. L. M. Verbers, Frederik M. Van Der Wateren, and Frans J. M. Vermeulen. "Provenance, geochemistry and grain-sizes of glacigene sediments, including the Sirius Group, and Late Genozoic Glaciol history of the southern Prince Albert Mountains, Victoria Land, Antarctica." Annals of Glaciology 27 (1998): 290–96. http://dx.doi.org/10.3189/1998aog27-1-290-296.

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The southern Prince Albert Mountains, between David and Mawson Glaciers (75°30' to 76°S) in Victoria Land, Antarctica, comprise a series of nunataks with elevations ranging from 800m near the coast to 2300 m ~130 km inland. Geochemical and grain-size analyses of tills from these nunataks reveal three major groups of deposits: (1) coarse to medium sandy tills, found on Glaciolly streamlined summit plateaus of Kirk-pat rick Basalt above 2000 ma.s.l.., with geochemical compositions very similar to those of the underlying jurassic Kirkpatrick Basalt; (2) bimodal silty and sanely tills of the Sirius Group with Ferrar/Beacon-dominated geochemical compositions, at elevations of 1300-1600 m a.s.l. on striated summit plateaus and high-elevation terraces; (3) fine-grained tills with high SiO2 contents from ice-cored moraines at the lee sides of large nunataks. The geochemical composition of sandy tills from the highest summit plateaus suggests that valleys had not yet cut through the Kirkpatrick Basalt and into Beacon and Ferrar rocks at the time of deposition. These tills represent a phase of temperate glaciation prior to deposition of diatom-bearing Sirius Group tills. The latter were deposited after a first phase of landscape dissection as inferred from geochemical data. The fine-grained ice-cored moraines are late-Pleistocene basal tills. The presence of pre-Pliocene Glacial deposits on high mountain summits in the Prince Albert Mountains has implications for the interpretation of high-elevation Sirius Group sediments in other areas of the Transantarctic Mountains. It is possible that the “Sirius debate” has its origin in interpretations of both thin, barren pre-Pliocene deposits on high mountain summits and thick sequences of diatom-bearing deposits in valleys elsewhere in the Transantarctic Mountains. Both types of deposits are associated with the Sirius Group, but they belong to separate Glacial episodes.

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Reeves, J. M., P. A. Gell, S. M. Reichman, A. J. Trewarn, and A. Zawadzki. "Industrial past, urban future: using palaeo-studies to determine the industrial legacy of the Barwon Estuary, Victoria, Australia." Marine and Freshwater Research 67, no. 6 (2016): 837. http://dx.doi.org/10.1071/mf15344.

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Around the globe, heavy industry has often been associated with estuaries, which provide water for operations, waste disposal and navigation. Many of these practices leave a legacy of contamination, which accumulate in the estuaries, which act as sediment sinks. Heavy metal contaminants may remain buried, even after the industrial practices are ceased. The Connewarre Complex is a series of wetlands, within the Port Philip and Bellarine Ramsar site. Through a unique combination of techniques, including diatom assemblages, biogeochemistry (δ13C, δ15N, C/N) and heavy metal content, the major anthropogenic influences over the last 170 years and the biotic response has been determined. Key features that can be elucidated include regulation of the waterways, establishment of heavy industry and major shifts in climatic conditions. In combination, these drivers have acted to rapidly shift the condition of the wetland from early in settlement such that the perceived ‘natural ecological character’ is actually an artificial one. The legacy of contamination is common to many Ramsar-listed wetlands. The lesson from this site is that, when making plans to manage the ecological condition of a wetland, past use needs to be considered to ensure that well meaning interventions do not exacerbate risk of mobilising contaminants best left undisturbed.

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Ngupula, GW, CN Ezekiel, ASE Mbonde, B. Kashindye, and E. Mboni. "Spatial distribution of soluble reactive silica (SRSi) in the Tanzanian waters of Lake Victoria and its implications for diatom productivity." African Journal of Aquatic Science 39, no. 1 (January 2, 2014): 109–16. http://dx.doi.org/10.2989/16085914.2014.888330.

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Tyler, Jonathan J., Keely Mills, Cameron Barr, J. M. Kale Sniderman, Peter A. Gell, and David J. Karoly. "Identifying coherent patterns of environmental change between multiple, multivariate records: an application to four 1000-year diatom records from Victoria, Australia." Quaternary Science Reviews 119 (July 2015): 94–105. http://dx.doi.org/10.1016/j.quascirev.2015.04.010.

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Jurado, Valme, Mariona Hernandez-Marine, Miguel Angel Rogerio-Candelera, Francisco Ruano, Clara Aguilar, Juan Aguilar, and Cesareo Saiz-Jimenez. "Cleaning of Phototrophic Biofilms in a Show Cave: The Case of Tesoro Cave, Spain." Applied Sciences 12, no. 15 (July 22, 2022): 7357. http://dx.doi.org/10.3390/app12157357.

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Show caves have different grades of colonization by phototrophic biofilms. They may receive a varied number of visits, from a few thousand to hundreds of thousands of visitors annually. Among them, Tesoro Cave, Rincon de la Victoria, Spain, showed severe anthropic alterations, including artificial lighting. The most noticeable effect of the lighting was the growth of a dense phototrophic community of cyanobacteria, algae and bryophytes on the speleothems, walls and ground. The biofilms were dominated by the cyanobacterium Phormidium sp., the chlorophyte Myrmecia israelensis, and the rhodophyte Cyanidium sp. In many cases, the biofilms also showed an abundance of the bryophyte Eucladium verticillatum. Other cyanobacteria observed in different biofilms along the cave were: Chroococcidiopsis sp., Synechocystis sp. and Nostoc cf. edaphicum, the green microalgae Pseudococcomyxa simplex, Chlorella sp. and the diatom Diadesmis contenta. Preliminary cleaning tests on selected areas showed the effectiveness of hydrogen peroxide and sodium hypochlorite. A physicochemical treatment involving the mechanical removal of the thickest layers of biofilms was followed by chemical treatments. In total, 94% of the surface was cleaned with hydrogen peroxide, with a subsequent treatment with sodium hypochlorite in only 1% of cases. The remaining 5% was cleaned with sodium hypochlorite in areas where the biofilms were entrapped into a calcite layer and in sandy surfaces with little physical compaction. The green biofilms from the entire cave were successfully cleaned.

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Mazard, Sophie L., Nicholas J. Fuller, Karen M. Orcutt, Oliver Bridle, and Dave J. Scanlan. "PCR Analysis of the Distribution of Unicellular Cyanobacterial Diazotrophs in the Arabian Sea." Applied and Environmental Microbiology 70, no. 12 (December 2004): 7355–64. http://dx.doi.org/10.1128/aem.70.12.7355-7364.2004.

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ABSTRACT An oligonucleotide primer, NITRO821R, targeting the 16S rRNA gene of unicellular cyanobacterial N2 fixers was developed based on newly derived sequences from Crocosphaera sp. strain WH 8501 and Cyanothece sp. strains WH 8902 and WH 8904 as well as several previously described sequences of Cyanothece sp. and sequences of intracellular cyanobacterial symbionts of the marine diatom Climacodium frauenfeldianum. This oligonucleotide is specific for the targeted organisms, which represent a well-defined phylogenetic lineage, and can detect as few as 50 cells in a standard PCR when it is used as a reverse primer together with the cyanobacterium- and plastid-specific forward primer CYA359F (U. Nübel, F. Garcia-Pichel, and G. Muyzer, Appl. Environ. Microbiol. 63:3327-3332, 1997). Use of this primer pair in the PCR allowed analysis of the distribution of marine unicellular cyanobacterial diazotrophs along a transect following the 67°E meridian from Victoria, Seychelles, to Muscat, Oman (0.5°S to 26°N) in the Arabian Sea. These organisms were found to be preferentially located in warm (>29°C) oligotrophic subsurface waters between 0 and 7°N, but they were also found at a station north of Oman at 26°N, 56°35′E, where similar water column conditions prevailed. Slightly cooler oligotrophic waters (<29°C) did not contain these organisms or the numbers were considerably reduced, suggesting that temperature is a key factor in dictating the abundance of this unicellular cyanobacterial diazotroph lineage in marine environments.

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Cocquyt, Christine, Wolf-Henning Kusber, and Regine Jahn. "Otto Müller’s Surirella taxa (Bacillariophyta) from East Africa, based on a historical collection kept at the Botanic Garden and Botanical Museum Berlin-Dahlem (B)." Afrika Focus 21, no. 1 (March 8, 2008). http://dx.doi.org/10.21825/af.v21i1.5049.

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At the beginning of the 20th century, Otto Müller described over 100 new freshwater diatom taxa from algae samples, collected during the German “Nyassa-See– und Kinga-Gebirgs-Expedition” in East Africa. He published valuable drawings and wrote detailed descriptions of these micro-algae, but subsequent authors regarded many of these African taxa to be synonyms or infraspecific of European species. In the last two decades renewed attention to the diatom flora of East Africa has made it evident that Müller’s taxa have to be reinvestigated, in terms of both light as well as scanning electron microscopy, in order to evaluate possible new or endemic species. This was recently done for his Surirella taxa, a typical component of the African Great Lakes diatom flora of which many species are endemic to this area. Additional data, originating from material of later periods in the same region (e.g. Lakes Tanganyika, Malawi, Victoria, Edward), was incorporated in the investigation to study the variability in valve morphology and the African distribution of each species. Otto Müller’s samples thus provide the means to study historical African diatom diversity as a baseline for modern biodiversity assessment. Type information and the English description for taxon have been published in international journals and online at the AlgaTerra Information System [www.algaterra.org], a site developed and updated by the Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM). High resolution digital photographs of the Surirella taxa will also be available in the future on the API website [www.aluka.org]. Key words: Algae, Diatoms, Historic Collections, East Africa

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Pissaridou, Panayiota, Agnès Bouchez, Marlen Vasquez Hadjilyra, Valentin Vasselon, Andreas Christou, Teofana Chonova, Katerina Drakou, et al. "Morphotaxonomy- and metabarcoding-based ecological assessment of Cyprus streams’ diatom communities and correlation with environmental and anthropogenic influences." ARPHA Conference Abstracts 4 (March 4, 2021). http://dx.doi.org/10.3897/aca.4.e64962.

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In freshwater ecosystems, periphytic biofilms include diatom assemblages that depend on environmental conditions (e.g., nutrient concentrations, salinity, temperature etc.). These assemblages respond rapidly to environmental changes, which makes diatoms valuable bioindicators. For this reason, they are currently used in freshwater biomonitoring programs (e.g., EU Water Framework Directive - WFD) (Foster et al., 2000). To date, diatom taxonomic identification is based on morphological criteria, which requires high taxonomic expertise to identify them to the species level needed for biomonitoring. Having this in mind, new strategies have been examined for the development of high-throughput, non-biased identification approaches. Human activities are the leading cause of environmental impairments and appropriate biomonitoring of ecosystems is needed to effectively assess the impact of their activities. In the last ten years, DNA metabarcoding combined with next-generation sequencing and bioinformatics, have been proposed as a complementary approach to morphological identification. In the past ten years, DNA metabarcoding coupled with next-generation sequencing and bioinformatics represents a complementary approach for diatom biomonitoring (Vasselon et al., 2019). In this study, this approach was used for the first time in Cyprus considering the association of environmental and anthropogenic pressures to diatom assemblages using the rbcL 312 bp barcode, next-generation sequencing (MiSeq Illumina), and bioinformatic evaluation (Mothur Software). Statistical analysis was then applied to identify the environmental (i.e., river types, geo-morphological) and anthropogenic (i.e., physical, chemical, human land-use pressures) variables' role in the observed diatom diversity. The Indice de Polluosensibilité Spécifique (IPS) index was used as it was shown to better respond to pressures that affect water quality in Cyprus rivers (WDD, 2014). Results indicate differences in diatom assemblages between intermittent and perennial rivers. Achnanthidium minutissimum was more abundant in intermittent rivers; whereas Amphora pediculus and Planothidium victorii (P. caputium) in perennial ones. Furthermore, we could demonstrate the correlation between nutrients (e.g., nitrogen, phosphorus), characteristics of the individual sampling sites (e.g., elevation), and land use activities on the observed differences in diatom diversity (Pissaridou, 2021). Additionally, results were compared to the morphotaxonomy-based approach which was conducted microscopically. Results show a positive correlation between morphological and molecular IPS scores. Points deviating from the norm are influenced by the limitations of both techniques. Fistulifera saprophila had a key role in this observation, as it negatively influences IPS scores. All in all, we conclude that DNA metabarcoding complements the morphological methodology for the ecological quality assessment of freshwaters in Cyprus. Multi-stressors and anthropogenic pressures have a significant statistical relationship to the observed diatom diversity and play a pivotal role in determining Cyprus' rivers' ecological status (Fig. 1). Foster, D., Wood, A., Griffiths, M., 2000. The Water Framework Directive (2000/60/EC) – An introduction Dave Foster – Policy Advisor (Europe), Aram Wood EP Scientist (Water), Dr Martin Griffiths – Head of Water Quality, Environment Agency, Head Office, Rio House, Waterside Drive, Aztec West, Almon 7–9. Pissaridou, P., Vasselon V., Christou A., Chonova T., Lacroix S., Papatheodoulou A., Drakou K., Tziortzis I., Dörflinger G., Rimet F., Bouchez A. and Vasquez MI. 2021 Deciphering Cyprus’ diatom diversity and the effects of environmental and anthropogenic influences for ecological assessment of rivers using DNA metabarcoding.Chemosphere (In Press) Vasselon, V., Frédéric, R., Isabelle, D., Olivier, M., Yorick, R., Agnès, B., 2019. Assessing pollution of aquatic environments with diatoms’ DNA metabarcoding: Experience and developments from France Water Framework Directive networks. Metabarcoding and Metagenomics 3, 101–115. https://doi.org/10.3897/mbmg.3.39646 WDD, 2014. Review and update of article 5 of Directive 2000/60/EC (Water reservoirs) & Classification of water status (Rivers, natural lakes and water reservoirs), That will establish baseline information and data for the 2nd cyprus river basin management plan.

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Raya-Montaño, Yurixhi Atenea, Maricela Apáez-Barrios, Ma Blanca Nieves Lara-Chávez, and Patricio Apáez-Barrios. "Producción de girasol ( Helianthus annuus L.) con aplicación foliar de tierra diatomea." Acta Agrícola y Pecuaria 8, no. 1 (June 9, 2022). http://dx.doi.org/10.30973/aap/2022.8.0081001.

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En México, en 47% de la superficie de cultivo de girasol (Helianthus annus L.), el rendimiento de grano es menor a 1.0 t ha-1. La tendencia de la agricultura es buscar alternativas de origen natural y amigables con el ambiente para incrementar el rendimiento agrícola. Por esta razón, en este estudio se estableció girasol cv. Victoria aceitero para determinar el efecto de la dosis (0.5, 1 y 1.5%) e intervalo (7, 14 y 21 días) de aplicación foliar de tierra diatomea sobre la producción de materia seca y rendimiento de grano de girasol. El diseño experimental fue de bloques completos al azar, con cuatro repeticiones en arreglo de parcelas divididas. La dosis de 1.0% cada 7 días generó el más alto rendimiento de grano (2,047 kg ha-1), seguido de esta misma dosis cada 14 días (1,715 kg ha-1), lo cual produjo la mayor cantidad de materia seca (1,219 g m-2).

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Justine Nakintu and Julius Bunny Lejju. "Environmental Dynamics of Lake Victoria: Evidence from a 10,000 14C yr Diatom Record from Napoleon Gulf and Sango Bay." Journal of Environmental Science and Engineering A 5, no. 12 (December 28, 2016). http://dx.doi.org/10.17265/2162-5298/2016.12a.005.

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Journal articles on the topic 'Diatoms Victoria'

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