Productivité végétale dans un marais intertidal d'eau douce, Québec (Québec)

1990 ◽  
Vol 68 (4) ◽  
pp. 852-856
Author(s):  
Hélène Gilbert
Keyword(s):  
Aquatic Vegetation ◽  
Seasonal Pattern ◽  
Dry Weight ◽  
Sagittaria Latifolia ◽  
Plant Associations ◽  
Zizania Aquatica ◽  
Annual Productivity ◽  
Freshwater Tidal Marsh ◽  
Below Ground ◽  
The City

Above- and below-ground annual productivity of vascular plants in the freshwater tidal marsh of the City of Québec (St. Lawrence River) was estimated to be 280 g dry weight/m2. This low productivity is explained in part by the very large surface of bare ground (23%), by the relative importance (39%) of the surface dominated by much less productive aquatic vegetation, and by the presence of embankments on the formerly most productive parts of the marsh. The most productive plant associations were those dominated by Scirpus americanus Pers. (606 g dry weight∙m−2∙a−1), Zizania aquatica L. var. brevis (702), Sagittaria rigida Pursh (598) and Sagittaria latifolia Willd. (834). Species productivities (in g dry weight∙m−2∙a−1) were 436 (Sc. americanus), 196 (Z. aquatica), 86 (Sa. rigida), and 685 (Sa. latifolia). An analysis of the biomass allocation (seasonal pattern) is presented for five species.

Modelling aquatic vegetation and dissolved oxygen after a flood event in the Bow River, Alberta, Canada

2009 ◽  
Vol 36 (3) ◽  
pp. 492-503 ◽  
Author(s):  
K. L. Robinson ◽  
C. Valeo ◽  
M. C. Ryan ◽  
A. Chu ◽  
M. Iwanyshyn
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Aquatic Vegetation ◽  
Dominant Role ◽  
Dry Weight ◽  
Flood Event ◽  
Species Competition ◽  
Quality Model ◽  
Wastewater Infrastructure ◽  
The City

Traditionally, macrophyte density has been considered the primary factor affecting the large dissolved oxygen fluctuations in the Bow River. After a major flood event scoured macrophytes in 2005, and subsequently changed river dynamics, the City of Calgary needed to update their predictive computer model for water quality to reflect the new conditions, which led to this study. A 2006 aquatic vegetation survey was also completed to assess post-flood conditions. The survey found that the average macrophyte dry weight was much lower (28 g/m2 ± 100 (p = 0.05)) than the historic average of 241 g/m2 ± 29, while the average periphyton chlorophyll-a concentration was higher (343 mg/m2 ± 71) than the historic average (158 mg/m2 ± 17)). Dissolved oxygen (DO) fluctuations were similar to pre-flood levels despite changes in the dominant vegetation. Using the results of this survey, the significant and previously unrecognized effects of periphyton diurnal processes on DO concentrations in the Bow River were identified and the Bow River water quality model (BRWQM) was recalibrated to reflect these findings. Adjustments were made to the BRWQM’s periphyton submodel to account for the more dominant role played by these organisms in river processes, and a competitive shading factor between macrophytes and periphyton was also introduced to more accurately model the species' competition for available sunlight. This newly calibrated and validated version of BRWQM was tested and found capable of predicting the occurrence of low DO concentrations in the Bow River and can provide a useful tool for forecasting the water quality effects of the city's planned wastewater infrastructure expansion.

Seasonal changes in biomass and shoot characteristics of a Zostera capricorni Aschers. Dominant meadow in Cairns Harbour, northern Queensland

1994 ◽  
Vol 45 (7) ◽  
pp. 1337 ◽  
Author(s):  
LJ McKenzie
Keyword(s):  
Surface Area ◽  
Seasonal Pattern ◽  
Light Availability ◽  
Environmental Parameters ◽  
Dry Weight ◽  
Spatial And Temporal Variability ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Leaf Surface Area ◽  
Below Ground

Spatial and temporal variability of Z. capricorni biomass, shoot characteristics (canopy height, surface area, flowering), distribution and detrital content were examined from December 1988 to December 1990. Between August 1987 and August 1991, 15% (2.0 ha) of the meadow was lost. Biomass of above- and below-ground structures showed a unimodal seasonal pattern with maxima in late spring (mean 194.92 g dry weight m-2 and 426.67 g DW m-2 respectively) and minima in winter (mean 28.72 g DW m-2 and 56.98 g DW m-2 respectively). Mean above-ground biomass (95.53 � 2.21 g DW m-2) was approximately half the mean below-ground biomass (177.28 � 4.49 g DW m-2). Leaf canopy heights were greatest between October and February (maximum 53.4 cm) and lowest around mid year (minimum 4.4 cm). Leaf surface area per square metre of seagrass meadow ranged from 10.28 to 1.39 m2 (mean 3,692 � 0.104 m2), and flowering occurred during September and October. Detrital biomass ranged from 339.73g DW m-2 to 11.83 g DW m-2 (mean 77.39 � 2.36 g DW m-2). Detrital biomass was higher during July-October and lower during February-May. The climate during the study was typical for the area, and all trials displayed similar seasonal patterns, although the amplitudes differed among some trials. The environmental parameters that may influence seagrass and detrital biomass were investigated. The best models explained only 14% of the variation in above-ground biomass, 15% of the variation in below-ground biomass, and 21% of the variation in detrital biomass. These models suggest that fluctuations in seagrass and detrital biomass in Cairns Harbour were influenced by changes in light availability, temperature, salinity and exposure.

Seasonal Variation of Suicide in the City of São Paulo, Brazil, 1996–2010

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe
Keyword(s):  
Seasonal Pattern ◽  
Total Sample ◽  
Sao Paulo ◽  
Seasonal Patterns ◽  
São Paulo ◽  
Health Statistics ◽  
Males And Females ◽  
June July ◽  
The City ◽  
Over Time

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.

Mites of the family Phytoseiidae (Parasitiformes, Mesostigmata) at the plants in Brovary town

2014 ◽  
Vol 25 (3-4) ◽  
pp. 77-83
Author(s):  
S. L. Grabovska ◽  
L. O. Kolodochka
Keyword(s):  
Phytoseiid Mites ◽  
Plant Associations ◽  
Species Complexes ◽  
District Center ◽  
The Family ◽  
Species Composition And Distribution ◽  
Dog Rose ◽  
The City ◽  
Species Being

This article deals with the results of study of species content and basic peculiarities of beaked mites-Phytoseiidae in plant associations of one of the regional centers of Ukraine. The species composition and distribution of mites-Phytoseiidae (Parasitiformes, Phytoseiidae) in plantations of Brovary town of Kyiv region were determined. Fourteen species of 8 genera of phytoseiid mites were found. Index of their existing and relative biotope connection of each registered species to vegetation types and plant species were computed. The study was conducted according to the results of material treatment on the territory of the mentioned city from 25 species of plants (16 species of hardy-shrub and 9 of herbaceous vegetations). The studies of distribution of plant-living mites-Phytoseiidae were conducted separately for hardy-shrub and herbaceous plants). The collection of faunistic material was executed during the vegetation of periods of 2011 and 2013. Within the city the collection of the material was conducted with hardy-shrub plants and herbaceous type of vegetation along the streets, in parks and squares of Brovary city of Kyiv region, district center, one of the satellite-cities of Kiev, the capital of Ukraine. The study of species complexes characteristics of mites was conducted with usage of data calculated on the basis of frequency index (Is), degree of relative habitat confinedness (F) (Pesenko, 1982) and domination index Paliy-Kovnatski (Di) (Shitikov, 2003). Only on one species of plant (F=1) 6 species of mites-Phytoseiidae were found – T.сotoneastri on blue spruce, T. laurae – on common spruce, T. aceri – on ash-leaved maple, P. incognitus – on dog-rose, P. soleiger – on mulberry-tree, A. caudiglans – on sea-buckthorn. These species can be related to stenoecic. The mentioned species are stenotopic only in relation to the sample of plants from the plant associations of Brovary, as in other regions these species of mites can populate the other species of plants. The rest 8 species, being registered on two or more types of plants, are related to euryoecic. Among them there is a group of 6 species with “positive tendencies to population of plants”, owning the indicators of habitat confinedness 0<F<1: A. andersoni (0,92–0,96), A. rademacheri (0,85–0,96), N. herbarius (0,92–0,96), T. tiliarum (0,66–0,77), A. pirianykae (0,73–0,99), A. clavata (0,82–0,98). The rest species, E. finlandicus и K. aberrans, have the expanded range of indicators in relation to habitat confinedness (-0,71<F<0,55 и -0,16<F<0,88), that specifies on their ability to populate the big quality of species. E. finlandicus has the negative indicator of relative habitat confinedness in relation to the plants of herbaceous morphotype that serves confirmation of the ecological peculiarity of the species detected earlier. The data of relative habitat confinedness of mites to certain species of plants shows availability of stenoecic (T.сotoneastri, T. laurae, T. aceri, P. incognitus, P. soleiger, A. caudiglans) and euryoecic species (A. andersoni, A. rademacheri, N. herbarius, E. finlandicus, K. aberrans, T. tiliarum, A. pirianykae, A. clavata). 

scholarly journals ESTIMASI CADANGAN KARBON PADA LAMUN DI PESISIR TIMUR KABUPATEN BINTAN

2018 ◽  
Vol 10 (3) ◽  
pp. 639-650
Author(s):  
. Khairunnisa ◽  
Isdradjad Setyobudiandi ◽  
Mennofatria Boer
Keyword(s):  
Global Warming ◽  
Carbon Content ◽  
Carbon Stock ◽  
East Coast ◽  
Dry Weight ◽  
Blue Carbon ◽  
Coastal Vegetation ◽  
Seagrass Ecosystem ◽  
Below Ground ◽  
Standard Value

ABSTRAKSalah satu upaya untuk mengurangi emisi gas karbon pemicu pemanasan global adalah dengan memanfaatkan vegetasi pesisir seperti lamun yang dikenal dengan istilah blue carbon. Penelitian ini bertujuan untuk mengetahui stok karbon pada padang lamun di Pesisir Timur Kabupaten Bintan, Kepulauan Riau sebagai upaya dalam mengurangi pemanasan global. Penelitian dilakukan di Berakit, Malang Rapat, dan Teluk Bakau mulai Januari – Juli 2017. Parameter yang diukur dalam penelitian ini adalah biomassa, kandungan karbon, dan stok karbon pada lamun. Analisis biomassa diukur dari berat kering lamun per satuan luas yang dibagi atas bagian atas dan bawah substrat, kandungan karbon diukur dengan metode Walkley and Black, stok karbon diukur dengan memperhatikan kandungan karbon dan biomassa lamun. Hasil penelitian menunjukkan ekosistem lamun di pesisir timur Kabupaten Bintan ditumbuhi oleh C. rotundata, C. serrulata, E. acoroides, H. uninervis, H. pinifolia, H. ovalis, T. hemprichii, T. ciliatum dan S. isoetifolium dengan kondisi yang relatif baik.  Persentase biomassa dan karbon yang berada di bawah substrat lebih besar dibanding biomassa yang berada di atas substrat, sehingga ketika bagian pelepah dan daun lamun lepas baik karena tindakan manusia ataupun alam lamun masih tetap mampu menyimpan karbon. Padang lamun di pesisir sebelah timur Kabupaten Bintan memiliki potensi dalam menyerap dan menyimpan karbon yakni sebesar 2431.33 ton C dengan E. acoroides sebagai spesies yang mampu menghasilkan biomassa terbesar dan kandungan karbon tertinggi, meski jumlah tersebut tidak dapat dijadikan acuan apakah lamun memiliki potensi yang tinggi ataupun tidak karena hingga saat ini belum ada nilai standardnya. ABSTRACTOne of the solutions to reduce carbon gas emissions that triggered global warming is to utilize coastal vegetation such as seagrass that known as blue carbon. This research was aimed to determine stock carbon on seagrass in the east coast of Bintan Regency, Kepulauan Riau Province as an effort to reduce global warming.  The research was conducted in Berakit, Malang Rapat, and Teluk Bakau from January to July 2017. The parameters measured in this research were biomass, carbon content, and carbon stock on seagrass. The anylisis of the biomass was obtained from the dry weight per unit area, the carbon content was obtained by Walkley and black method, the carbon stock was obtained by the measurement of the biomass and carbon content. Based on the observation, seagrass ecosystem in east coast of Bintan was palnted by C. rotundata, C. serrulata, E. acoroides, H. uninervis, H. pinifolia, H. ovalis, T. hemprichii, T. ciliatum, dan S. isoetifolium. The below ground biomass and carbon percentation were higher that the aboveground parts so when the leaves are released either because of human or natural actions, seagrass is still able to store carbon. Seagrass beds on the east coast of Bintan Regency have the potential to absorb and store carbon which is equal to 2431.33 tons C as E. acoroides being the species which capable of producing the highest biomass and highest carbon content, although this number cannot be used as a reference whether seagrass has high potential or no because until now there has been no standard value. 

Allelopathic Influence of Germinating Seeds and Seedlings of Cover Crops on Weed Species

Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Melinda L. Hoffman ◽  
Leslie A. Weston ◽  
John C. Snyder ◽  
Emilie E. Regnier
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Resource Competition ◽  
Petri Dish ◽  
Dry Weight ◽  
Weed Species ◽  
Allelopathic Potential ◽  
Below Ground ◽  
Allelopathic Interference ◽  
Radicle Length

Bioassays using binary mixtures that included a cover crop with known allelopathic potential and a weed species were employed to determine the importance of allelopathy compared to resource competition as interference mechanisms. Responses of weed species germinated with cover crops in a petri dish were measured. Interference between weed and cover crop seedlings was determined in a greenhouse experiment using the additive design, which included partitions to reduce above- and below-ground competition and used capillary mat subirrigation to control moisture and fertilizer availability. Germinating sorghum reduced radicle length of weeds, whereas germinating rye tended to increase weed radicle length. Methods limited above-ground competition, so likely interference mechanisms were below-ground competition and allelopathy. Germination with a cover crop had little effect on germination and shoot length of weeds. Increased density of rye but not of sorghum reduced growth of barnyardgrass seedlings. Reduced number of barnyardgrass leaves in the presence of rye was likely due to allelopathy. Suppression of barnyardgrass dry weight attributed to allelopathic interference by rye was successfully separated and compared to the combined effects of competition and allelopathy.

The Black Diamonds of Sydney Harbour

2019 ◽  
Vol 2 (3) ◽  
pp. 645-664
Author(s):  
Ann Elias
Keyword(s):  
Indigenous Peoples ◽  
Mining Company ◽  
Pastoral Area ◽  
The Sublime ◽  
Sydney Harbour ◽  
History Of ◽  
Below Ground ◽  
The Aesthetic ◽  
The City

This article explores the case study of a coal mine that was first tunneled under Sydney Harbour in 1897 but closed in 1931. Specifically, it examines how the history of the mine intersects with aesthetics, race, colonialism, and Indigenous dispossession. Centered on the story of an English mining company that first sought a mine site in a pastoral area of the city, but under public pressure was forced to select instead a grimy working class suburb on the opposite harbor shore, the article argues that environmental aesthetics and tastes in beauty collaborated with extractivism. The argument emerges that economics, art, and aesthetics are inextricably linked in this history and further, that while the mine excited the industrial imagination through the aesthetic of the sublime, and associations with darkness and vastness, it conflicted with colonial settler tastes for the pastoral imagination defined by the aesthetics of the beautiful and its associations with light. The article discusses the context of a settler economy in lands stolen from Indigenous peoples, and how conceptualizations of the sublime and beautiful, as well as dark and light, were aligned with the racialization of the properties of coal and space above and below ground.

Carbon resource sharing and rhizome expansion of Phalaris aquatica plants in grazed pastures

2005 ◽  
Vol 32 (1) ◽  
pp. 79 ◽  
Author(s):  
Brendan R. Cullen ◽  
David F. Chapman ◽  
Paul E. Quigley
Keyword(s):  
Resource Sharing ◽  
Seasonal Pattern ◽  
Soil Surface ◽  
Deep Roots ◽  
Phalaris Aquatica ◽  
Plant Parts ◽  
Grazed Pastures ◽  
Below Ground ◽  
Grazing Systems ◽  
Western Victoria

The patterns of carbon (C) resource sharing and new rhizome development in phalaris (Phalaris aquatica L. cv. Australian) were examined in grazed pastures in western Victoria. The seasonal pattern of new rhizome growth was similar under the four grazing systems tested. New rhizome production was infrequent but concentrated in winter. The phalaris plants maintained more than 1600 kg DW ha–1 of non-assimilating material beneath the soil surface (0–5 cm). Gaseous 14C was fed into plants in the field to determine if these below ground structures continued to be supported by the C assimilating tillers. The results indicated that the primary tiller does provide C to support the growth of secondary and tertiary tillers derived from its axillary buds. There was some evidence that C was exported from the fed tiller to non-assimilating plant structures. The old reproductive tiller bases (from which the assimilating tillers originate) received some C support, suggesting that this was maintained because it had deep roots attached. C export to older plant parts declined, which may lead to plant fragmentation.

scholarly journals Simulating Carbon Sequestration using Cellular Automata and land use assessment; Case of: Karaj City, Iran

2017 ◽  
Author(s):  
Ali Khatibi ◽  
Sharareh Pourebrahim ◽  
Mazlin Mokhtar
Keyword(s):  
Land Use ◽  
Carbon Sequestration ◽  
Cellular Automata ◽  
Dry Weight ◽  
Soil Samples ◽  
Barren Area ◽  
Average Value ◽  
Class Average ◽  
Effective Use ◽  
The City

Abstract. In this study, in the city of Karaj five classes of land use-cover including residential, agriculture, rangeland, forest and barren areas were considered and randomly in each class a total of 20 points were selected and vegetation and soil samples were taken. In plant samples, the amount of carbon sequestration was determined by calculating the amount of organic carbon by dry weight and in soil samples, the amount of carbon sequestration was determined by using Walleky and Black method, too. For each area, the average value of carbon sequestration of samples was introduced as carbon sequestration index of that class. Average values for each category were determined as an indicator of carbon sequestration of that class and then by using the DINAMICA EGO software a simulation was conducted using cellular automata approach to simulate changes in the classes of land use-cover in the city of Karaj. Finally, by using carbon sequestration index and the results of the simulation, changes in carbon sequestration in each class were calculated. On this basis, it was found that in the 15-year period from 2014 to 2029, not considering the residential class as the effective use of carbon sequestration, the greatest amount of carbon sequestration was found in the agricultural class and the lowest carbon sequestration was found in barren area. Also, agriculture class will be faced with the huge reduction of carbon sequestration, because of expansion of the residential area.

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