scholarly journals EFFECTS OF FARGESIA DENUDATA DENSITY ON SEASONAL CHANGES IN LITTER NUTRIENT CONCENTRATIONS AND THEIR POTENTIAL RETRANSLOCATION

2005 ◽  
Vol 29 (4) ◽  
pp. 537-542
Author(s):  
WU Fu-Zhong ◽  
◽  
WANG Kai-Yun ◽  
YANG Wan-Qin ◽  
LU Ye-Jiang ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Nutrient Concentrations ◽  
Fargesia Denudata

scholarly journals Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  
Keyword(s):  
Water Quality ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Cover ◽  
Critical Role ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Dry Tropics ◽  
The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

scholarly journals Seasonal Changes of Nutrient Concentrations in Water of Some Locations in Southern Iraqi Marshes, After Restoration.

2009 ◽  
Vol 6 (4) ◽  
pp. 711-718
Author(s):  
Baghdad Science Journal
Keyword(s):  
Seasonal Changes ◽  
T Test ◽  
Nutrient Concentrations ◽  
P Value ◽  
Statistical Program ◽  
Nutrients Concentration ◽  
Colorimetric Methods

After restoration of Iraqi marshes during 2003, three locations were chosen, one in each main marsh (Um Al-Naaj site in Al-Hwaizeh marsh; Al-Nagarah site in Al-Hammar marsh and Al-Baghdadia site in Al-Chebaysh marsh) to determine the concentrations of nutrients (Nitrate, Nitrite, Phosphate and Silicate) in water seasonally for the period winter, spring, summer, and autumn at 2007. Five water replicates were collected from each site, seasonally. In the Lab., the samples were analyzed by colorimetric methods; the results showed that Um-Al-Naaj site has the highest nutrients level, while Al-Nagarah site has the lowest level. The statistical program t-test was applied at the significant levels (P-value < 0.01) and (P-value < 0.05) to know the significant differences in the nutrients concentration among the sites, as well as among the seasons. Statistically, the results showed that NO3, NO2, and PO4 concentrations have significant differences among the sites, as well as among the seasons. While, SiO2 concentrations have no significant differences among the sites, but they differed significantly among the seasons.

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 changes of the concentrations of mineral forms of nitrogen and phosphorus in watercourses in the agricultural catchment area (Bay of Puck, Baltic Sea, Poland)

2018 ◽  
Vol 19 (3) ◽  
pp. 986-994 ◽  
Author(s):  
E. Wojciechowska ◽  
N. Nawrot ◽  
K. Matej-Łukowicz ◽  
M. Gajewska ◽  
H. Obarska-Pempkowiak
Keyword(s):  
Baltic Sea ◽  
Seasonal Changes ◽  
Arable Land ◽  
Phosphorus Compounds ◽  
Nutrient Concentrations ◽  
The Baltic Sea ◽  
Nitrogen And Phosphorus ◽  
Sources Of Pollution ◽  
Biogenic Compounds ◽  
The Baltic

Abstract The Baltic Region countries are obliged to meet the stringent limits of N and P discharge set by HELCOM for 2021. Area sources of pollution, including agriculture, are considered the main contributors of biogenic compounds. The Bay of Puck as an inner part of the Baltic Sea is particularly sensitive to eutrophication caused by nutrient inflow from agricultural lands. Rivers and streams inflowing to the Bay of Puck transport nitrogen and phosphorus compounds washed out from fields. The article discusses concentrations of nitrogen and phosphorus compounds measured during annual research (VII.2017 – VI.2018) at three watercourses: Płutnica, Reda and Błądzikowski Stream inflowing to the Bay of Puck. The concentrations ranged from 0.01 to 0.13 mg/L N-NO2, from 0.39 to 7.55 mg/L N-NO3, from 0.03 to 0.58 mg/L N-NH4, from 0.44 to 9.51 mg/L TN, from 0.05 to 0.45 mg/L P-PO4 and from 0.03 to 1.89 mg/L TP. Seasonal changes of nutrient concentrations were observed, with maximum concentrations of nitrates in August and September after application of fertilizers to arable land.

Seasonal and long term changes of the phytoplankton in the lake Tortum in relation to environmental factors, Erzurum, Turkey

Biologia ◽  
2006 ◽  
Vol 61 (4) ◽  
Author(s):  
Ersin Kivrak
Keyword(s):  
Seasonal Changes ◽  
Phytoplankton Community ◽  
Water Mass ◽  
Secchi Depth ◽  
Nutrient Concentrations ◽  
Phytoplankton Community Structure ◽  
Ceratium Hirundinella ◽  
Long Term Changes ◽  
One Year

AbstractSeasonal changes in phytoplankton community structure of the lake Tortum were studied over one year period, from March 2002 to February 2003. The collected data were compared with the data collected 21 years ago. Chlamydomonas microsphaerella, Cyclotella krammeri, C. glomerata, and Ceratium hirundinella were identified to be dominant several times during the study period. Species diversity and biomass of the phytoplankton were very low in spite of sufficient and high levels of nutrient concentrations. Maximum phytoplankton density levels were observed during summer and late autumn. Phytoplankton density was positively correlated with nutrients, temperature and pH, and it was negatively correlated with Secchi depth and dissolved oxygen. Phytoplankton growths were negatively affected from water transparency and high levels of water mass transport (circulation) and velocity in the lake.

Sign in / Sign up

Export Citation Format

Share Document