Diatoms from surface sediments of the northern part of Lake Tanganyika

227 Diatom taxa were observed in the surface sediments of the northern part of Lake Tanganyika, including 1 new to science: Amphora tanganyikae. The diatom community of these sediments is mainly composed of benthic organisms while planktonic diatoms are rather rare. Many brackish-water and a few marine organisms were observed. Cosmopolitan organisms (77.1%) dominate the diatom flora but tropical, tropical African and African taxa are also well represented (22.9%)Deceased.Deceased.     

The Life History Flora of Japan—A New Series

Abstract Plant Species Biology will publish a continuing series of papers on the biology and life history of vascular plant species indigenous to or well naturalized in the flora of Japan. This paper sets forth the guidelines and format for contributors to this series. This new series attempts to establish a record as complete as possible concerning all aspects of the life history characteristics as well as significant biosystematic characters of the species under consideration, and keen attention will be given to the species which are becoming very rare and endangered, especially in the lowland areas and aquatic habitats (e.g., rivers and ponds).     

Insights on the Use of Hybrid Life Cycle Assessment for Environmental Footprinting

Establishing a comprehensive environmental footprint that indicates resource use and environmental release hotspots in both direct and indirect operations can help companies formulate impact reduction strategies as part of overall sustainability efforts. Life cycle assessment (LCA) is a useful approach for achieving these objectives. For most companies, financial data are more readily available than material and energy quantities, which suggests a hybrid LCA approach that emphasizes use of economic input‐output (EIO) LCA and process‐based energy and material flow models to frame and develop life cycle emission inventories resulting from company activities. We apply a hybrid LCA framework to an inland marine transportation company that transports bulk commodities within the United States. The analysis focuses on global warming potential, acidification, particulate matter emissions, eutrophication, ozone depletion, and water use. The results show that emissions of greenhouse gases, sulfur, and particulate matter are mainly from direct activities but that supply chain impacts are also significant, particularly in terms of water use. Hotspots were identified in the production, distribution, and use of fuel; the manufacturing, maintenance, and repair of boats and barges; food production; personnel air transport; and solid waste disposal. Results from the case study demonstrate that the aforementioned footprinting framework can provide a sufficiently reliable and comprehensive baseline for a company to formulate, measure, and monitor its efforts to reduce environmental impacts from internal and supply chain operations.     

From Life Cycle Assessment to Life Cycle Management

Life cycle assessment (LCA) is a widely accepted methodology to support decision‐making processes in which one compares alternatives, and that helps prevent shifting of environmental burdens along the value chain or among impact categories. According to regulation in the European Union (EU), the movement of waste needs to be reduced and, if unavoidable, the environmental gain from a specific waste treatment option requiring transport must be larger than the losses arising from transport. The EU explicitly recommends the use of LCA or life cycle thinking for the formulation of new waste management plans. In the last two revisions of the Industrial Waste Management Programme of Catalonia (PROGRIC), the use of a life cycle thinking approach to waste policy was mandated. In this article we explain the process developed to arrive at practical life cycle management (LCM) from what started as an LCA project. LCM principles we have labeled the “3/3” principle or the “good enough is best” principle were found to be essential to obtain simplified models that are easy to understand for legislators and industries, useful in waste management regulation, and, ultimately, feasible. In this article, we present the four models of options for the management of waste solvent to be addressed under Catalan industrial waste management regulation. All involved actors concluded that the models are sufficiently robust, are easy to apply, and accomplish the aim of limiting the transport of waste outside Catalonia, according to the principles of proximity and sufficiency.     

Diatoms in surface sediments of the Indonesian Archipelago and their relation to hydrography

Diatoms from 53 surface sediments (water depth 350–7200 m) of the Indonesian Archipelago were studied to determine the recent distribution of important assemblages. Three significant assemblages were distinguished, each related to hydrographic parameter(s) of the overlying water mass. The first assemblage is related to the warm saline surface waters of Pacific and Indian Ocean origin; the second assemblage reflects the low-salinity lobe in Makassar Strait; and the third corresponds to major seasonal upwelling areas in the Arafura Sea and south of Java.The normalized ratio of typically Pacific Ocean and Indian Ocean species reflects the fluctuations of the Pacific versus Indian Ocean inflow during the Late Quaternary.Absolute diatom abundances (ADA; in valves g^–1 carbonate-free dry wt) and diatom accumulation rates (DAR; in valves CM^–2 ka^–1) of autochthonous species did not correspond to daily rates of primary production in the photic zone and consequently cannot be used for paleoproductivity estimates.Besides vertical transport some lateral transport of diatoms occurs, as was demonstrated by the presence of three groups of allochthonous species. They are indicators of productivity in the littoral environment, bottom currents and river outflow.     

The Life History and Occurrence of Sialis lutaria L. (Megaloptera) in the Littoral Zone of Lake Esrom,Denmark

The life history and distribution of Sialis lutaria L. in the exposed littoral zone of Lake Esrom, Denmark were examined during 1979/80. Sialis showed an annual life cycle with mean annual abundance of 20 and 40 ind m⁻² at 0.4 and 2.0 m depth, respectively. Growth peaked during July with rates of about 10 % d⁻¹. Net annual production averaged 0.2 g DW at 0.4 m depth and 0.8 g DW at 2.0 m depth. The annual P/B-ratios were estimated in the range of 4.6-7.1.     

宽礁膜的生活史

在国内首次观察描述了宽礁膜(Monostroma latissimum Wittrock)生活史各阶段的形态结构特征和发育变化,并对其单性生殖进行了周年培养和观察.大型的雌雄异体的膜状配子体成熟后,放散双鞭毛的配子,小型的球状孢子体成熟后放散四鞭毛的游孢子,其生活史是单倍体的配子体与二倍体的孢子体互相交替的异形世代交替.另外,在生活史中还发现合子和孢子囊的二分裂增殖方式,一年生配子体和二年生孢子囊等现象.未接合的雌、雄配子固着后变成球状单细胞体,室内培养后发育成成熟的单性孢子囊,并放散四鞭毛的游孢子,这些游孢子固着后,可直接发育成膜状的配子体,单性生殖也可以用来进行人工育苗.     

宽礁膜的生活史

在国内首次观察描述了宽礁膜(Monostroma latissimum Wittrock)生活史各阶段的形态结构特征和发育变化,并对其单性生殖进行了周年培养和观察。大型的雌雄异体的膜状配子体成熟后,放散双鞭毛的配子,小型的球状孢子体成熟后放散四鞭毛的游孢子,其生活史是单倍体的配子体与二倍体的孢子体互相交替的异形世代交替。另外,在生活史中还发现合子和孢子囊的二分裂增殖方式,一年生配子体和二年生孢子囊等现象。未接合的雌、雄配子固着后变成球状单细胞体,室内培养后发育成成熟的单性孢子囊,并放散四鞭毛的游孢子,这些游孢子固着后,可直接发育成膜状的配子体,单性生殖也可以用来进行人工育苗。     

Diatoms and their relationship to environmental variables from lakes and ponds on Bathurst Island, Nunavut, Canadian High Arctic

Baseline and historical environmental data are sparse in the High Arctic, however diatom assemblages preserved in high arctic lake and pond sediment profiles can provide proxy data of past environmental changes. Ecological data, however, are still sparse. Diatom taxa preserved in the surficial sediment of lakes and ponds on Bathurst Island (75° 42 N, 97° 21 W), Nunavut, Canadian High Arctic, and their relationship to 34 environmental variables were examined using multivariate statistics. A total of 148 diatom taxa were identified from the surface sediments of 29 study sites. Five environmental variables, Fe³⁺, Total Phosphorus (Unfiltered) (TPU), Total Nitrogen (TN), Temperature (TEMP) and pH significantly (P0.05) accounted for most of the variation in the diatom assemblages. TN was also significantly correlated to other variables (e.g. TPF, DOC, POC). A CCA constrained to TN indicated that this variable best explained the species distributions, and a weighted-averaging (WA) model was developed to infer nutrient levels from the relative abundances of the 58 dominant taxa. Interestingly, previous limnological work indicated that nitrogen most likely limited algal production in some of these high arctic sites. This model may be used to quantitatively estimate past TN levels from diatom assemblages preserved in sediment cores from Bathurst Island, and may provide a means to track past environmental changes in the High Arctic.     

Life History and Secondary Production of Mayflies (Ephemeroptera) Indicate Disturbance in Two Small Carpathian Streams

The life histories and the secondary production of 9 mayflies (Ephemeroptera) species were studied at two sites in a submountain stream (West Carpathians, Slovakia). The disturbed site has a deforested and converted to meadows and pastures catchment and the undisturbed one is a well‐preserved submountain stream with 60% of the catchment covered by spruce forests. Differences in the forest cover and in the thermal regime of both streams were reflected in the structural as well as the functional measures. At the undisturbed site, the total secondary production of mayfly community was more than two times higher (3568 mg DW m^–2 y^–1) than at the disturbed site (1446 mg DW m^–2 y^–1). Species could be divided according to their affinity to particular disturbance level. Ecdyonurus picteti, Rhithrogena carpatoalpina, Habrophlebia lauta and Habroleptoides confusa appeared to prefer undisturbed conditions. On the contrary, Ecdyonurus aurantiacus and Habrophlebia fusca occurred only at the disturbed site. The dominant species Baetis rhodani and Electrogena samalorum did not show any clear preference regarding the catchment disturbance. However, nymphs of Electrogena samalorum seem to be more successful at the disturbed site, where they reached bigger body sizes (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Presence and Localization of Thioredoxins in Diatoms,Unicellular Algae of Secondary Endosymbiotic Origin

Diatoms are unicellular algae of great ecological importance. So far, very little is known about the regulation of carbon fixation in these algae; however, there are strong indications that in diatom plastids, the ferredoxin/thioredoxin system might play a minor role in redox regulation of the photosynthetic reactions compared to land plants. Until now, it is unknown whether there are fewer or other target enzymes of thioredoxins in diatoms. Only a single potential target enzyme for thioredoxin, the plastidic fructose-l,6-bisphosphatase, has yet been identified. Nevertheless, during the annotation of the genome of the diatom Phaeodactylum tricornutum, we identified several genes encoding different thioredoxins. Utilizing in vivo expression of GFP：presequence fusion proteins in P. tricornutum, we were able to show that these thioredoxins are targeted either into plastids, mitochondria, or remain in the cytosol. Surprisingly, two of the three usually cytosolic thioredoxin h proteins are apparently plastid associated and, together with a thioredoxin reductase, putatively located in the periplastidic compartment. This is one of the few indications for so far unknown enzymatic reactions in the space between the two pairs of diatom plastid envelope membranes.     

New Insights into the Evolutionary History of Type 1 Rhodopsins

Type 1 (archaeal) rhodopsins and related rhodopsin-like proteins had been described in a few halophile archaea, -proteobacteria, a single cyanobacteria, some fungi, and a green alga. In exhaustive database searches, we detected rhodopsin-related sequences derived not only from additional fungal species but also from organisms belonging to three groups in which opsins had hitherto not been described: the -proteobacterium Magnetospirillum magnetotacticum, the cryptomonad alga Guillardia theta, and the dinoflagellate Pyrocystis lunula. Putative plant and human type 1 rhodopsin sequences found in the databases are demonstrated to be contaminants of fungal origin. However, a highly diverged sequence supposedly from the plant Oryza sativa was found that is, together with the Pyrocystis sequence, quite similar to -proteobacterial rhodopsins. These close relationships suggest that at least one horizontal gene transfer event involving rhodopsin genes occurred between prokaryotes and eukaryotes. Alternative hypotheses to explain the current phylogenetic range of type 1 rhodopsins are suggested. The broader phylogenetic range found is compatible with an ancient origin of type 1 rhodopsins, their patchy distribution being caused by losses in multiple lineages. However, the possibility of ancient horizontal transfer events between distant relatives cannot be dismissed.     

Distribution of Epilithic Diatoms in Response to Environmental Conditions in an Urban Tropical Stream, Central Kenya

Use of diatoms in monitoring water quality is well acknowledged in developed countries, but only recently has the assessment started gaining importance in developing countries. Diatoms can be obtained from natural and artificial substrates. Appreciating the differences and similarities of diatom assemblages on both substrates may contribute to a better understanding and standardization particularly during monitoring of water quality. During this study we assessed diatom assemblages, biodiversity and trophic indices in relation to water quality along the Nairobi River. Fifteen sites were sampled in September 2000 during the dry season. Diatoms were collected from natural substrates (stones, pebbles) and artificial substrates (100% acrylic wool). On artificial and natural substrates, a total of 190 and 151 taxa were found, respectively, the majority of these taxa (80%) have cosmopolitan distribution and are also widespread throughout tropical African. Species composition changed downstream, five taxa dominated upper and mid stream sites whereas lower stream sites were dominated by one or two taxa. Species richness, diversity, dominance and evenness were positively correlated with NO₃, O₂ and altitude but decreased markedly downstream with a simultaneous increase in total dissolved solids, alkalinity, chemical oxygen demand and PO₄. Ordination and classification (CANOCO and TWINSPAN) showed that diatom assemblages in the Nairobi River responded strongly to water quality changes with respect to concentrations of NO₃, NO₂, total dissolved solids and temperature. Taxa common at less impacted upstream sites included Gomphonema gracilis, Anomoeoneis brachysira and Fragilaria biceps; while common taxa at midstream sites with agricultural catchments were Gomphonema parvulum, Navicula cryptocephala, N. schroeteri, N. bryophila, N. halophila, Nitzschia linearis var. linearis and Cymbella silesica. Achnanthes minutissima var. saprophila, Gomphonema angustum, Navicula subminuscula, N. arvensis, Nitzschia palea and N. umbonata were most common at urban sites, which were polluted by residential and industrial effluents. Trophic diatom indices suggested that water quality was poor at most sites in the Nairobi River. Most sites along the river had low Generic Diatom Index values, GDI (<12) and high Trophic Diatom Index values, TDI 73–78 (median = 76) and 75–84 (median = 77) for artificial and natural substrates, respectively. This study showed that diatoms' response on natural and artificial substrates were similar and reflected environmental conditions correctly.