scholarly journals SEASONAL VARIATIONS OF NUTRIENT BUDGETS IN JAKARTA BAY, INDONESIA

2014 ◽  
Vol 35 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Mochamad Saleh Nugrahadi ◽  
Tetsuo Yanagi ◽  
Iwan G. Tejakusuma ◽  
Seno Aji ◽  
Rahmania A. Darmawan
Keyword(s):  
Suspended Matter ◽  
Rainy Season ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Nutrient Budgets ◽  
Phytoplankton Abundance ◽  
Dissolved Nutrients ◽  
Carbon And Nitrogen ◽  
Estuarine Coastal ◽  
Nitrogen Phosphorus

This study aims to quantify the fluxes of carbon, nitrogen, phosphorus, and silicate in Jakarta Bay and use these flux data to gain an initial understanding of the biogeochemical processes occurring in the system. We investigated water, suspended matter and sediments fluxes from estuarine, coastal water and outside of the bay. Water samples were analyzed for dissolved nutrients, chlorophyll-phytoplankton abundance, and their composition. Suspended matter and sediment were analyzed for carbon and nitrogen. Nutrient concentrations were high in the rivers or estuaries and then decreased rapidly seaward. Calculation budget results showed that Jakarta Bay is a sink for DIP, DIN and DSi during dry season and rainy season. In the dry season, the system is in the slightly fixation condition ([nfix-denit] = 0.03 mmol N m-2 d-1). In contrast, denitrification exceed nitrogen fixation ([nfix-denit] = -9.74 mmol N m-2 d-1) in the rainy season. Moreover, the bay produced net carbon about 2.6-32 mmol C m-2 d-1.

scholarly journals Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil

2011 ◽  
Vol 83 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Giulliari A. S. T. Lira ◽  
Elcida L. Araújo ◽  
Maria Do Carmo Bittencourt-Oliveira ◽  
Ariadne N. Moura
Keyword(s):  
Rainy Season ◽  
Phytoplankton Community ◽  
Dry Season ◽  
Cylindrospermopsis Raciborskii ◽  
Phytoplankton Abundance ◽  
Vertical Variation ◽  
Total Phytoplankton ◽  
Physical And Chemical Variables ◽  
Different Depths ◽  
Physical And Chemical

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

scholarly journals Temporal variation in the phytoplankton community of Acapulco Bay, Mexico

2012 ◽  
Vol 3 (1) ◽  
pp. 4 ◽  
Author(s):  
Agustín A. Rojas-Herrera ◽  
Juan Violante Gonzalez ◽  
Sergio García-Ibáñez ◽  
Víctor M.G. Sevilla-Torres ◽  
Jaime S. Gil-Guerrero ◽  
...  
Keyword(s):  
Species Composition ◽  
Temporal Variation ◽  
Rainy Season ◽  
Phytoplankton Community ◽  
Species Abundance ◽  
Sampling Period ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Diatom Species ◽  
Oceanic Environments

<p>Species composition and abundance of the phytoplankton community in Acapulco Bay, Mexico, were studied from May to December 2009. Samples were collected at 5 stations (4 coastal and 1 oceanic) at 3 depths (1, 5 and 10 m). Eighty-seven species were identified: 54 dinoflagellates, 32 diatoms and 1 silicoflagellate. The community was structured mainly by adiaphoric species, that is, species adapted to both neritic and oceanic environments. Species abundance and composition varied significantly during the sampling period due to increased nutrient concentrations in the rainy season. Dinoflagellate species were more abundant during the dry season, and diatom species dominated numerically during the rainy season.</p>

scholarly journals Influence of river discharge on phytoplankton structure and nutrient concentrations in four tropical semiarid estuaries

2016 ◽  
Vol 64 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Hortência de Sousa Barroso ◽  
Helena Becker ◽  
Vânia Maria Maciel Melo
Keyword(s):  
Urban Areas ◽  
Rainy Season ◽  
River Discharge ◽  
Inorganic Nitrogen ◽  
Dry Season ◽  
Northeastern Brazil ◽  
Nutrient Concentrations ◽  
Freshwater Species ◽  
Rainy Period ◽  
Phytoplankton Structure

Abstract This study evaluated changes in phytoplankton and nutrients after an increase in river discharge in four estuaries of northeastern Brazil. Samples were taken during a markedly freshwater-deprived period (Nov/2010, dry season), and during a rainy season (May/2011). While two estuaries are located in urban areas (Ceará - CE and Cocó - CO), the others are markedly freshwater-deprived (Pacoti - PAC and Pirangi - PIR). Our findings indicate that increased freshwater had opposing effects on estuaries impacted by anthropogenic discharges (CO, CE and PIR) compared with the other, less impacted (PAC). In CO and CE, the freshwater flow during the rainy period had a nutrient diluting effect and controlled phytoplankton blooms. In PIR, only phosphorus and inorganic nitrogen decreased in the rainy season. In contrast, an increase of all nutrients was observed in PAC, and of TN in PIR, followed by an increase in phytoplankton biomass. In the rainy season, eutrophic freshwater species dominated in all the estuaries. In the dry season, blooms of Cryptomonas/Rhodomonas and Synechocystis aquatilis were, respectively, observed in CE and CO. Also in the dry season, PAC and PIR had a predominance of marine species under a condition of hypersalinity. Canonical correspondence analysis suggested the variation observed for salinity, silica, and TN are the main driver of phytoplankton structure.

scholarly journals Vertical distribution, nutrient concentration and seasonal changes of fine root mass in a semi-deciduous tropical dry forest and in two adjacent pastures in the Western Llanos of Venezuela

2020 ◽  
Vol 8 (2) ◽  
pp. 93-104
Author(s):  
Ana Francisca González-Pedraza ◽  
Nelda Dezzeo
Keyword(s):  
Vertical Distribution ◽  
Seasonal Changes ◽  
Rainy Season ◽  
Nutrient Concentration ◽  
Fine Root ◽  
Tropical Dry Forest ◽  
Dry Season ◽  
Dry Forest ◽  
Nutrient Concentrations ◽  
Root Mass

With the objective to contribute to a better understanding of ecological consequences of deforestation on the below-ground system in the Western Llanos of Venezuela, we evaluated the vertical distribution, nutrient concentration and seasonal changes of total fine root mass (FRM) (<2 mm diameter) in a semi-deciduous tropical dry forest and in 2 adjacent pastures of Cynodon nlemfuensis: a young pasture (YP, 5 years old) and an old pasture (OP, 18 years old) in the Obispo municipality, Barinas State. This evaluation included measurements at the end of the rainy season, during the dry season and during the subsequent early rainy season in 2005/2006. Highest FRM was recorded during the dry season, which probably indicates a plant water-stress response mechanism. The highest proportion (63‒88%) of FRM was concentrated in the 10–20 cm soil layer at all studied sites, probably due to a higher nutrient and moisture content at that depth. Non-significant differences (P>0.05) were observed in the total concentrations of organic carbon, nitrogen, phosphorus, calcium and magnesium in the FRM in soils supporting forest, OP and YP at the evaluated depths. Non-significant changes in the total FRM and nutrient concentrations were observed between the sampling periods and the 3 study sites. YP soils showed a slight increase in FRM that could be associated with the root growth of secondary vegetation, which is considered a weed and is periodically removed. Our results suggest that the land use change from tropical forest to pastures has not significantly affected the mass of fine roots and their carbon and nutrient concentrations. Further studies are needed to determine if these findings apply to other ecosystems.

scholarly journals Seasonal dynamics of carbon and nutrients from two contrasting tropical floodplain systems in the Zambezi River basin

2015 ◽  
Vol 12 (24) ◽  
pp. 7535-7547 ◽  
Author(s):  
A. L. Zuijdgeest ◽  
R. Zurbrügg ◽  
N. Blank ◽  
R. Fulcri ◽  
D. B. Senn ◽  
...  
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
River Basin ◽  
Particulate Organic Matter ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Carbon And Nitrogen ◽  
Zambezi River Basin ◽  
Zambezi River

Abstract. Floodplains are important biogeochemical reactors during fluvial transport of carbon and nutrient species towards the oceans. In the tropics and subtropics, pronounced rainfall seasonality results in highly dynamic floodplain biogeochemistry. The massive construction of dams, however, has significantly altered the hydrography and chemical characteristics of many (sub)tropical rivers. In this study, we compare organic-matter and nutrient biogeochemistry of two large, contrasting floodplains in the Zambezi River basin in southern Africa: the Barotse Plains and the Kafue Flats. Both systems are of comparable size but differ in anthropogenic influence: while the Barotse Plains are still in large parts pristine, the Kafue Flats are bordered by two hydropower dams. The two systems exhibit different flooding dynamics, with a larger contribution of floodplain-derived water in the Kafue Flats and a stronger peak flow in the Barotse Plains. Distinct seasonal differences have been observed in carbon and nutrient concentrations, loads, and export and retention behavior in both systems. The simultaneous retention of particulate carbon and nitrogen and the net export of dissolved organic and inorganic carbon and nitrogen suggested that degradation of particulate organic matter was the dominant process influencing the river biogeochemistry during the wet season in the Barotse Plains and during the dry season in the Kafue Flats. Reverse trends during the dry season indicated that primary production was important in the Barotse Plains, whereas the Kafue Flats seemed to have both primary production and respiration occurring during the wet season, potentially occurring spatially separated in the main channel and on the floodplain. Carbon-to-nitrogen ratios of particulate organic matter showed that soil-derived material was dominant year-round in the Barotse Plains, whereas the Kafue Flats transported particulate organic matter that had been produced in the upstream reservoir during the wet season. Stable carbon isotopes suggested that inputs from the inundated floodplain to the particulate organic-matter pool were important during the wet season, whereas permanent vegetation contributed to the material transported during the dry season. This study revealed effects of dam construction on organic-matter and nutrient dynamics on the downstream floodplain that only become visible after longer periods, and it highlights how floodplains act as large biogeochemical reactors that can behave distinctly differently from the entire catchment.

scholarly journals Nutrient uptake of Archidium acanthophyllum and Cyanotis lanata from Savanna Microsites on Baasi Inselberg in Southwestern Nigeria

2020 ◽  
Vol 8 ◽  
pp. 10
Author(s):  
Olubukunola Oluwole Oyesiku
Keyword(s):  
Growth Rate ◽  
Rainy Season ◽  
Bare Soil ◽  
Dry Season ◽  
Primary Sources ◽  
Nutrient Concentrations ◽  
Plant Tissues ◽  
Plant Debris ◽  
Southwestern Nigeria ◽  
Ion Contents

Nutrient concentrations and their mobility between soil and two dominant plants, moss (Archidium acanthophyllum Snider. (Archidiaceae) and succulent monocot (Cyanotis lanata Benth. Commelinaceae) growing on Baasi -Inselberg was investigated over a period of 36 months. The surface of the inselberg was divided into four microsites (Ms). Ms-1, bare soil; Ms-2, A. acanthophyllum only; Ms-3, C. lanata only; Ms-4, both Ms-2 and Ms-3. Samples of soil and plants were taken from one quadrat (0.5 m x 0.5 m) in each microsite for analysis of their ion contents. Plant debris, dust and rain water formed the primary sources of nutrients on the inselberg. Early rainfall (in April) triggered the growth of A. acanthophyllum which peaked in May and sharply decreased in June. Thereafter growth rate increased gradually from June to December (early dry season) and remained constant between January and March. In the early rainy season and early dry season, nutrient 2+ -1 + -1 2+ -1 + -1concentrations were higher (Ca , 1500 µgg ; K , 150 µg g ;Mg , 100 µg g ;Na , 30 µg g ) than other months of the seasons. In Ms-4 there was a higher resultant sequestration of ions in the plant tissues + -1 2+ -1 2+ -1 + -1 + (K , 800 µgg ;Ca , 600 µgg ; Mg , 160 µgg ;Na , 28 µgg ). The Ms-1 was the source of Na + 2+ 2+concentration in Ms-4, for K Ms-2 and Ms-3, for Mg Ms-2 only and for Ca Ms-1, 2 and 3.

scholarly journals Simulation of suspended sediment and black carbon transport in surface water layer of Ha Long bay

2019 ◽  
Vol 19 (2) ◽  
pp. 233-241
Author(s):  
Le Duc Cuong ◽  
Nguyen Van Thao
Keyword(s):  
Surface Layer ◽  
Black Carbon ◽  
Suspended Sediment ◽  
Suspended Matter ◽  
Rainy Season ◽  
Water Layer ◽  
Dry Season ◽  
Particulate Carbon ◽  
The North ◽  
Long Bay

Delft3D model employed to simulate the distribution and transport of suspended sediment and black carbon in Ha Long bay shows outcomes meeting with results from previous experiment studies. In the rainy season, suspended matter in surface layer is mainly in waters of western and southwestern Cat Ba island regions, and from Cua Luc toward the south nearshore areas with concentration of 50–130 g/m3. The concentration of suspended setdiment in the waters from Cua Luc to the north nearshore area is from 20 g/m3 to 50 g/m3 and that of offshore areas is 2–20 g/m3. In the dry season, the average concentrations of suspended matter are lower, approximately 110–150 g/m3 compared to the rainy season. In the rainy season, the total particulate carbon in surface layer is 0.0016–0.0028 kg/m3 and in the dry season, it ranges from 0.0001–0.005 kg/m3.

STUDI BIONOMIK VEKTOR MALARIA DI KECAMATAN KALIBAWANG, KULONPROGO

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Sardjito Eko Windarso dkk
Keyword(s):  
Land Use ◽  
Malaria Vector ◽  
Rainy Season ◽  
Dry Season ◽  
Physical Factors ◽  
Mosquito Vector ◽  
Anopheles Species ◽  
Commercial Farming ◽  
Study Results ◽  
Dry And Rainy Seasons

The increasing of malaria cases in recent years at Kecamatan Kalibawang has been suspected correspond with the conversion of farming land-use which initiated in 1993. Four years after the natural vegetation in this area were changed become cocoa and coffee commercial farming estates, the number of malaria cases in 1997 rose more than six times, and in 2000 it reached 6085. This study were aimed to observe whether there were any differences in density and diversity of Anopheles as malaria vector between the cocoa and mix farming during dry and rainy seasons. The results of the study are useful for considering the appropriate methods, times and places for mosquito vector controlling. The study activities comprised of collecting Anopheles as well as identifying the species to determine the density and diversity of the malaria vector. Both activities were held four weeks in dry season and four weeks in rainy season. The mea-surement of physical factors such as temperature, humidity and rainfall were also conducted to support the study results. Four dusuns which meet the criteria and had the highest malaria cases were selected as study location. Descriptively, the results shows that the number of collected Anopheles in cocoa farming were higher compared with those in mix horticultural farming; and the number of Anopheles species identifi ed in cocoa farming were also more varied than those in the mix horticultural farming.Key words: bionomik vektor malaria, anopheles,

scholarly journals Understanding variability in greenhouse gas emission estimates of smallholder dairy farms in Indonesia

2021 ◽  
Author(s):  
Titis Apdini ◽  
Windi Al Zahra ◽  
Simon J. Oosting ◽  
Imke J. M. de Boer ◽  
Marion de Vries ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Rainy Season ◽  
Greenhouse Gas Emission ◽  
Dairy Farms ◽  
Dry Season ◽  
Enteric Fermentation ◽  
Tropical Regions ◽  
Population Mean ◽  
Smallholder Dairy ◽  
Smallholder Dairy Farms

Abstract Purpose Life cycle assessment studies on smallholder farms in tropical regions generally use data that is collected at one moment in time, which could hamper assessment of the exact situation. We assessed seasonal differences in greenhouse gas emissions (GHGEs) from Indonesian dairy farms by means of longitudinal observations and evaluated the implications of number of farm visits on the variance of the estimated GHGE per kg milk (GHGEI) for a single farm, and the population mean. Methods An LCA study was done on 32 smallholder dairy farms in the Lembang district area, West Java, Indonesia. Farm visits (FVs) were performed every 2 months throughout 1 year: FV1–FV3 (rainy season) and FV4–FV6 (dry season). GHGEs were assessed for all processes up to the farm-gate, including upstream processes (production and transportation of feed, fertiliser, fuel and electricity) and on-farm processes (keeping animals, manure management and forage cultivation). We compared means of GHGE per unit of fat-and-protein-corrected milk (FPCM) produced in the rainy and the dry season. We evaluated the implication of number of farm visits on the variance of the estimated GHGEI, and on the variance of GHGE from different processes. Results and discussion GHGEI was higher in the rainy (1.32 kg CO2-eq kg−1 FPCM) than in the dry (0.91 kg CO2-eq kg−1 FPCM) season (P < 0.05). The between farm variance was 0.025 kg CO2-eq kg−1 FPCM in both seasons. The within farm variance in the estimate for the single farm mean decreased from 0.69 (1 visit) to 0.027 (26 visits) kg CO2-eq kg−1 FPCM (rainy season), and from 0.32 to 0.012 kg CO2-eq kg−1 FPCM (dry season). The within farm variance in the estimate for the population mean was 0.02 (rainy) and 0.01 (dry) kg CO2-eq kg−1 FPCM (1 visit), and decreased with an increase in farm visits. Forage cultivation was the main source of between farm variance, enteric fermentation the main source of within farm variance. Conclusions The estimated GHGEI was significantly higher in the rainy than in the dry season. The main contribution to variability in GHGEI is due to variation between observations from visits to the same farm. This source of variability can be reduced by increasing the number of visits per farm. Estimates for variation within and between farms enable a more informed decision about the data collection procedure.

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