Variability in surface water chemistry and phytoplankton biomass in two tropical, tidally dominated mangrove creeks

1999 ◽  
Vol 50 (5) ◽  
pp. 451 ◽  
Author(s):  
L. A. Trott ◽  
D. M. Alongi

Surface water concentrations of dissolved nutrients and phytoplankton biomass (as chlorophyll a) were examined monthly in relation to physicochemical characteristics and rainfall for 30 months in two tropical, tidally dominated mangrove creeks in north Queensland, Australia. Dissolved nutrient concentrations and phytoplankton biomass peaked during summer with no or little significant change throughout the rest of the year. Dissolved nitrogen and phosphorus concentrations correlated inversely with salinity changes, implying that fresh water and suspended material from the watershed were the main source of dissolved nutrients.The mean dissolved inorganic N : P ratio in each creek (Control Creek 58 : 1, Sandfly Creek 26 : 1) was greater than the Redfield ratio (16 : 1), suggesting excess nitrogen relative to phosphorus. Variability in phytoplankton biomass did not correlate significantly with dissolved nitrogen or phosphorus concentrations, but did relate to rainfall patterns and changes in dissolved oxygen concentrations.These results suggest that pelagic conditions in these mangrove creeks are constant all year round, except during the summer wet season.

2001 ◽  
Vol 52 (2) ◽  
pp. 235 ◽  
Author(s):  
Lester J. McKee ◽  
Bradley D. Eyre ◽  
Shahadat Hossain ◽  
Peter R. Pepperell

Water quality was monitored on a spatial and temporal basis in the subtropical Richmond River catchment over two years. Nutrient concentrations varied seasonally in a complex manner with highest concentrations (maximum =3110 µg N L – 1 and 572 µg P L –1 ) associated with floods. However, median (444 µg N L – 1 and 55 µg P L – 1 ) concentrations were relatively low compared with other parts of the world. The forms of nitrogen and phosphorus in streams varied seasonally, with greater proportions of inorganic nitrogen and phosphorus during the wet season. Minimum nutrient concentrations were found 2—3 months after flood discharge. With the onset of the dry season, concentration increases were attributed to point sources and low river discharge. There were statistically significant relationships between geology and water quality and nutrient concentrations increased downstream and were significantly related to population density and dairy farming. In spite of varying geology and naturally higher phosphorus in soils and rocks in parts of the catchment, anthropogenic impacts had the greatest effects on water quality in the Richmond River catchment. Rainfall quality also appeared to be related both spatially and seasonally to human activity. Although the responses of the subtropical Richmond River catchment to changes in land use are similar to those of temperate systems of North America and Europe, the seasonal patterns appear to be more complex and perhaps typical of subtropical catchments dominated by agricultural land use.


2012 ◽  
Vol 12 (4) ◽  
pp. 439-450
Author(s):  
Yong Qiu ◽  
Hanchang Shi ◽  
He Jing ◽  
Rui Liu ◽  
Qiang Cai ◽  
...  

Lake Taihu in China is a eutrophicated lake surrounded by industrial and urbanized zones, thus its water quality often suffers from organic and nutrient contaminants. In this paper, a 1 year water quality survey was conducted around the lake and statistical analysis tools were used to characterize the variations of organic pollutants. Analysis of variance (ANOVA), cluster analysis and principal component analysis (PCA) confirm the seasonal and spatial variations of surface water quality in Lake Taihu. Surface water quality is better during the wet season and worse downstream during the dry season. The dissolved organic matter was further analyzed using a parallel factor analysis (PARAFAC) model with three-dimensional excitation-emission fluorescence matrices. Four components were extracted from the fluorescence data, namely, two autochthonous biodegradation products (C1: amino acids, C4: protein-like materials) and two humic-like substances (C2: from microbial processing, C3: terrestrial). C1 and C4 were dominant in the chromophoric dissolved organic matter (CDOM) fluorophores; this result is similar to those of other inland water bodies in China. The CDOM fluorophores showed similar seasonal and spatial variations with common water quality indices, with the exception of the seasonal responses of C2 in winter. Bivariance correlations between the organic and nutrient concentrations and the fluorescence intensities of the CDOM fluorophores imply possible common sources of the different contaminants. This paper exemplifies advanced statistical methods as a useful tool in understanding the behavior of contaminants in inland fresh water systems.


2008 ◽  
Vol 59 (6) ◽  
pp. 467 ◽  
Author(s):  
Travis S. Elsdon ◽  
Karin E. Limburg

Although it is well known that land use affects nutrient dynamics and algal growth in streams, the responses to different durations of nutrient supply are poorly understood. The associations of benthic (periphyton-dominated) biomass with concentrations of dissolved nitrogen and phosphorus in rural and urban streams in New York were quantified. Biomass was significantly greater (2-fold) in the urban compared with the rural stream, which was associated with differences in dissolved nutrients. Experimental field enrichment of nutrient concentrations and duration of exposure altered benthic periphyton. Increasing nutrients by 60–99% of ambient concentrations increased periphyton percentage cover and biomass. Periphyton abundance also increased with increasing duration of exposure to nutrients (2, 4 and 8 weeks); however, short-term pulses of nutrients (2 weeks) had no significant effect in the rural stream. These results indicate that effective management of nutrient delivery, by reducing time periods of high nutrient load, will minimise impacts to benthic environments.


Author(s):  
Laima Berzina ◽  
Ritvars Sudars

Seasonal Characterisation and Trends Study of Nutrient Concentrations in Surface Water from Catchments with Intensive Livestock Farming Temporal changes in observed nitrogen and phosphorus losses to surface water were studied in 3 agricultural catchments in order to evaluate the achievement of water protection targets in Latvia. The aim of this study is to investigate the water quality measures in high density livestock farming catchments. Long-term monitoring data (years 1996-2008) of water quality used in the analysis show a high annual and monthly variability of nutrients. The results demonstrate little or no reduction of nutrient concentrations in surface water. The results suggest that water protection measures for agricultural production need to be further intensified.


2018 ◽  
Vol 22 (1) ◽  
pp. 487-508 ◽  
Author(s):  
Liang Yu ◽  
Joachim Rozemeijer ◽  
Boris M. van Breukelen ◽  
Maarten Ouboter ◽  
Corné van der Vlugt ◽  
...  

Abstract. The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN), total phosphorus (TP), NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type) for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban–agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs) in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88) between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate from the decomposition of organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater–surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.


1995 ◽  
Vol 52 (3) ◽  
pp. 587-606 ◽  
Author(s):  
Dale H. Vitt ◽  
Suzanne E. Bayley ◽  
Tai-Long Jin

Surface and subsurface (0.5, 1.0, and 1.5 m depths) water was sampled weekly in 1989 and biweekly in 1990 during the ice-free season along a bog-rich fen gradient in central Alberta. Acidity–alkalinity were most closely related to peatland type and were the most useful parameters for characterizing peatlands. Potassium, nitrogen, and phosphorus concentrations were more related to season, year, or peatland–year interactions and cannot be used to categorize the bog–fen gradient. Hydrogen ion, ammonium, alkalinity, and corrected conductivity were relatively constant throughout the ice-free season, while total metal ions (Al, Fe, Mn, and Zn), base cations (Ca2+, Mg2+, Na+, K+), nitrate, and components of phosphorus fluctuated seasonally. Nitrate remained constant with depth in all peatland types, whereas ammonium increased with depth. Relationships of surface water chemistry to pH for all sites showed three patterns: a positive and highly significant correlation with little seasonal variation within peatland types (base cations, alkalinity, and corrected conductivity); less significant correlation with strong seasonal variation within peatland types (N and P); and a general negative and highly significant correlation with some seasonal variation in peatland types (metals and S). Water temperatures increased along the bog-rich fen gradient.


2021 ◽  
Vol 3 ◽  
Author(s):  
Alicia M. Wilson ◽  
Meghan Shanahan ◽  
Erik M. Smith

Salt marshes serve as zones of intense groundwater mixing and reaction between freshwater uplands and estuaries. This raises the question of whether the impacts of upland development on nutrient and carbon species can be transmitted through salt marshes via groundwater, or whether salt marshes can buffer estuarine waters from coastal development. We sampled groundwater from fifteen tidal creek basins in South Carolina to test for compositional differences associated with development and marsh width. Groundwater samples from near creekbanks and below freshwater uplands were analyzed for salinity, total dissolved nitrogen and phosphorus, and dissolved organic carbon. Analyses revealed significantly higher TDN and TDP concentrations in creekbank samples from developed watersheds, independent of the season. Analyses of upland samples revealed significantly lower DOC concentrations in developed uplands, again independent of season. These results support the hypothesis that development can affect groundwater compositions in coastal groundwater and therefore may affect coastal nutrient and carbon fluxes. However, results also revealed significant linear correlations between marsh width, salinity, and nutrient concentrations in some marshes. These results suggest that salt marshes can act as buffers for development, and specifically suggests that the buffering capacity of salt marshes increases with width. Narrow or trenched salt marshes are far less likely to be effective buffers.


2001 ◽  
Vol 44 (4) ◽  
pp. 365-371 ◽  
Author(s):  
Mônica Aparecida Leite Silva ◽  
Claudia Ferreira Calasans ◽  
Alvaro Ramon Coelho Ovalle ◽  
Carlos Eduardo Rezende

The Paraíba do Sul river lower reach was monitored monthly between August 1995 and July 1996. This study was aimed at evaluating the temporal dynamics of dissolved nitrogen and phosphorus and its main controlling factors. Minimum and maximum observed values were as follows: N-NO2- - 0.08/0.51; N-NO3- - 21/57; N-NH4+ - 1.4/6.7; DON - 4.9/86.0; DIN -24.5/60.9; P-PO4(3-) - 0.43/1.66; DOP - 0.05/0.92; pH - 6.2/7.8; Dissolved Oxygen - 6.4/10.1; Conductivity - 48/74; Temperature - 20.5/31.1 (Nutrients - µM; Dissolved Oxygen - mg/l; Conductivity - µS/cm; Temperature - °C). Discharge presented a characteristic seasonal variation, showing a peak in January. Increasing P-PO4(3-), DOP, N-NH4+ and N-NO2- concentrations with increasing discharges could be associated to the partial flooding of inumerous fluvial islands and floodplains and to the agricultural practices of sugar cane crops that during the wet season could transfer nitrogen and phosphorus compounds to the fluvial channel.


1995 ◽  
Vol 31 (8) ◽  
pp. 155-158 ◽  
Author(s):  
J. W. H. van der Kolk ◽  
R. F. A. Hendriks

In the Bergambacht polder in The Netherlands, the surface water system is highly eutrophic. Owing to this high nutrient concentration, duckweed grows abundantly. To reduce the nutrient concentrations in the surface water, remedial measures are needed. To predict the effectiveness of three measures, a combination of a nutrient leaching model and a water quality model for nutrients in the surface water system was used. The scenarios formulated on the basis of these measures were simulated over a period of 35 years. Removing duckweed results in a substantial reduction of nitrogen and phosphorus. Improving the water purification plants results in a small reduction in the average nutrient concentrations. Dredging the total sediment layer results in a large reduction of phosphorus concentrations, but leads to an increase in nitrogen concentrations. The three measures combined will not improve the nitrogen concentration 30 years after implementation, but the phosphorus concentration will be reduced by 80% compared with 1990.


2020 ◽  
Author(s):  
Mengyuan Zhu ◽  
Guangwei Zhu ◽  
Hans Paerl ◽  
Wei Zhang ◽  
Hai Xu

<p>Daily monitoring over a period of one year in Lake Taihu, China, included chlorophyll a (Chl-a) and nutrient measurements, determining the taxonomic composition of the phytoplankton community and various water column physicochemical parameters. Chl-a and nutrient concentrations showed strong circadian variations ‒ Chl-a rised during daylight hours, while ammonium and phosphate rised at night. Chl-a concentrations also showed strong seasonal variations, with one annual peak in spring and another from summer to autumn, dominated by Dolichospermum spp. and Microcystis spp. respectively. Temperature appeared to exert the most important effect in this species succession. A nutrient‒Chl-a balance calculation indicated that both nitrogen and phosphorus in the water column could be limiting factors for phytoplankton growth during bloom periods. Over two thirds of particulate nutrients was attributed to phytoplankton biomass during blooms. Daily (or weekly) monitoring data provided more precise description of water quality, capturing short-term peaks in phytoplankton biomass, and reduced risks of under- or overestimating trophic levels in lakes, which always happened when using monthly monitoring data.</p>


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