scholarly journals Longitudinal distribution of Copepoda populations in the transition zone of Paranapanema river and Jurumirim Reservoir (São Paulo, Brazil) and interchange with two lateral lakes

2004 ◽  
Vol 64 (1) ◽  
pp. 11-26 ◽  
Author(s):  
S. M. C. Casanova ◽  
R. Henry
Keyword(s):  
Transition Zone ◽  
Suspended Solids ◽  
River Mouth ◽  
River System ◽  
High Water ◽  
Water Velocity ◽  
Longitudinal Distribution ◽  
System A ◽  
Main River ◽  
Abundance And Distribution

Longitudinal changes in composition, abundance, and distribution of copepods were studied at the transition zone of Paranapanema River-Jurumirim Reservoir (SP, Brazil). The interchange of biotic material between marginal lakes and the river system was also examined. Water samples were obtained from 6 stations along a stretch of 13 km of the Paranapanema River, from an upstream reach with high water velocity up to the river mouth into Jurumirim Reservoir. Two other sites in lateral lakes were also sampled. Nine copepod taxa were identified: 3 calanoids (Argyrodiaptomus furcatus Sars, Notodiaptomus iheringi Wright, and N. conifer Sars) and 6 cyclopoids (Eucyclops Claus, Microcyclops Claus, Mesocyclops longisetus Thiébaud, Thermocyclops decipiens Fischer, T. minutus Lowndes, and Paracyclops Claus). Harpacticoids were also collected. Calanoid and cyclopoid nauplii and copepodids, and harpacticoids were the most abundant organisms. In general, there was a longitudinal decrease in copepod abundance, whereas an increase was detected near the lakes. The abundance of most copepods was inversely correlated with current velocity and suspended solids. Higher abundance was observed in the river main course during the rainy season, during which there is a higher connectivity between the lakes and the main river. This promotes exportation of biologic material from marginal lakes to the river system, a biotic exchange reflecting the importance of marginal lakes to the river community structure.

scholarly journals Eutrophication mitigation in rivers: 30 years of trends in spatial and seasonal patterns of biogeochemistry of the Loire River (1980–2012)

2015 ◽  
Vol 12 (8) ◽  
pp. 2549-2563 ◽  
Author(s):  
C. Minaudo ◽  
M. Meybeck ◽  
F. Moatar ◽  
N. Gassama ◽  
F. Curie
Keyword(s):  
Dissolved Oxygen ◽  
Chlorophyll A ◽  
Seasonal Variations ◽  
River System ◽  
Longitudinal Distribution ◽  
Seasonal Patterns ◽  
Nutrient Load ◽  
Main River ◽  
Loire River ◽  
Monthly Survey

Abstract. Trends and seasonality analysis from 1980 onward and longitudinal distribution, from headwaters to estuary, of chlorophyll a, nitrate and phosphate were investigated in the eutrophic Loire River. The continuous decline of phosphate concentrations which has been recorded since 1991 both in the main river and in the tributaries has led to the conclusion that it was responsible for the significant reduction in phytoplanktonic biomass across the whole river system, although Corbicula spp. clams invaded the river during the same period and probably played a significant role in the phytoplankton decline. While eutrophication remained lower in the main tributaries than in the Loire itself, they were found to contribute up to ≈ 35% to the total nutrient load of the main river. The seasonality analysis revealed significant seasonal variations for the different eutrophication metrics and calls into question the classical monthly survey recommended by national or international authorities. Reducing P inputs impacted these seasonal variations: the decline of seasonal amplitudes of chlorophyll a reduced the seasonal amplitude of orthophosphate and of daily variations of dissolved oxygen and pH but did not significantly affect the seasonal amplitude of nitrate. Thus, the influence of phytoplankton on seasonal variations of nitrate was minor throughout the period of study.

Adult lake sturgeon ( Acipenser fulvescens Rafinesque, 1817) occurrence in the Muskegon River system, a Lake Michigan drowned river mouth, USA

2020 ◽  
Vol 36 (5) ◽  
pp. 547-558
Author(s):  
Brandon S. Harris ◽  
Carl R. Ruetz ◽  
Travis J. Ellens ◽  
Anthony D. Weinke ◽  
Bopaiah A. Biddanda
Keyword(s):  
Lake Michigan ◽  
River Mouth ◽  
River System ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
System A

scholarly journals Eutrophication mitigation in rivers: 30 years of trends and seasonality changes in biogeochemistry of the Loire River (1980–2012)

2014 ◽  
Vol 11 (12) ◽  
pp. 17299-17337 ◽  
Author(s):  
C. Minaudo ◽  
M. Meybeck ◽  
F. Moatar ◽  
N. Gassama ◽  
F. Curie
Keyword(s):  
Aquatic Vegetation ◽  
River System ◽  
Longitudinal Distribution ◽  
Terrestrial Vegetation ◽  
Exact Role ◽  
P Limitation ◽  
Main River ◽  
Algal Pigment ◽  
Loire Basin ◽  
Loire River

Abstract. Trends and seasonality analysis since 1980 and longitudinal distribution from headwaters to estuary of algal pigment, nitrate and phosphate were investigated in the eutrophic Loire River. The continuous decline of phosphate concentrations recorded since 1991 both in the main river and in the tributaries led to a significant reduction in algal biomass across the whole river system. While eutrophication remained lower in the main tributaries than in the Loire itself, they were found to contribute up to 45% to the total nutrient load of the main river. The seasonality analysis revealed that the river has always been under P limitation, explaining why reducing P inputs led to decreasing eutrophication in the whole Loire basin. The decline of seasonal amplitudes of algal pigments reduced the seasonal amplitude of phosphate and of daily variations of dissolved oxygen and pH but did not significantly affect the seasonal amplitude of nitrate. Thus, algal uptake responsibility on the summer nitrate loss seemed to be declining, questioning the exact role played by denitrification, terrestrial vegetation and fixed aquatic vegetation on the nitrogen cycle.

Establishing an empirical equation for the relationship between total suspended solids and total phosphorus concentrations in the downstream Red river water

2020 ◽  
Vol 20 (3) ◽  
pp. 325-332
Author(s):  
Le Nhu Da ◽  
Le Thi Phuong Quynh ◽  
Phung Thi Xuan Binh ◽  
Duong Thi Thuy ◽  
Trinh Hoai Thu ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Suspended Solids ◽  
Empirical Relationship ◽  
Water Environment ◽  
Total Suspended Solids ◽  
River System ◽  
Red River ◽  
Reservoir Impoundment ◽  
Downstream Section ◽  
Reasonable Prediction

Recently, the Asian rivers have faced the strong reduction of riverine total suspended solids (TSS) flux due to numerous dam/reservoir impoundment. The Red river system is a typical example of the Southeast Asian rivers that has been strongly impacted by reservoir impoundment in both China and Vietnam, especially in the recent period. It is known that the reduction in total suspended solids may lead to the decrease of some associated elements, including nutrients (N, P, Si) which may affect coastal ecosystems. In this paper, we establish the empirical relationship between total suspended solids and total phosphorus concentrations in water environment of the Red river in its downstream section from Hanoi city to the Ba Lat estuary based on the sampling campaigns conducted in the dry and wet seasons in 2017, 2018 and 2019. The results show a clear relationship with significant coefficient between total suspended solids and total phosphorus in the downstream Red river. It is expressed by a simple equation y = 0.0226x0.3867 where x and y stand for total suspended solids and total phosphorus concentrations (mg/l) respectively with the r2 value of 0.757. This equation enables a reasonable prediction of total phosphorus concentrations of the downstream Red river when the observed data of total suspended solids concentrations are available. Thus, this work opens up the way for further studies on the calculation of the total phosphorus over longer timescales using daily available total suspended solids values.

Evaluation of nutrient runoff from the kako river by continuous daily sampling

1996 ◽  
Vol 34 (12) ◽  
pp. 67-72
Author(s):  
Yukio Komai
Keyword(s):  
Suspended Solids ◽  
Water Discharge ◽  
Electronic Conductivity ◽  
High Water ◽  
Nutrient Loads ◽  
Discharge Condition ◽  
Nutrient Runoff ◽  
Average Value ◽  
Daily Sampling ◽  
A Site

A water sample was taken once a day for 15 months at a site near an estuary of the Kako River, Japan, to estimate nutrient loads from rivers to the sea. Total phosphorus (T-P), total nitrogen (T-N), suspended solids (SS) and electronic conductivity (EC) were measured. T-P and SS concentrations varied in proportion to the discharge, and T-P concentrations increased with those of SS, too. EC varied inversely with the discharge, but the fluctuations of T-N concentrations were less than those of T-P and SS concentrations. Water quality remained, for the most part, constant throughout the day. T-P, T-N and SS load were 181t/year, 2320t/year and 51000t/year in 1992, respectively, 54% of T-P load, 47% of T-N load and 80% of SS loads outflowed in those cases where the discharge was more than 100 m3/s, which were 36 days in 1992. 79% of T-P load, 69% of T-N load and 92% of SS load outflowed in periods of high water discharge, which were 88 in 1992. T-P and T-N loads calculated by using one day's data in every month were 151t/year and 2450t/year. But nutrient loads calculated by using the average value of data from an ordinary discharge were two or three times lower than calculated yearly loads. These results showed the importance of estimating the yearly load considering the discharge condition and sampling at a time of high water discharge.

Seagrass depth range and water quality in southern Moreton Bay, Queensland, Australia

1996 ◽  
Vol 47 (6) ◽  
pp. 763 ◽  
Author(s):  
EG Abal ◽  
WC Dennison
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Suspended Solids ◽  
Light Attenuation ◽  
River Mouth ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
Depth Range ◽  
Moreton Bay ◽  
A Site

Correlations between water quality parameters and seagrass depth penetration were developed for use as a biological indicator of integrated light availability and long-term trends in water quality. A year-long water quality monitoring programme in Moreton Bay was coupled with a series of seagrass depth transects. A strong gradient between the western (landward) and eastern (seaward) portions of Moreton Bay was observed in both water quality and seagrass depth range. Higher concentrations of chlorophyll a, total suspended solids, dissolved and total nutrients, and light attenuation coefficients in the water column and correspondingly shallower depth limits of the seagrass Zostera capricorni were observed in the western portions of the bay. Relatively high correlation coefficient values (r2 > 0.8) were observed between light attenuation coefficient, total suspended solids, chlorophyll a, total Kjeldahl nitrogen and Zostera capricorni depth range. Low correlation coefficient values (r2 < 0.8) between seagrass depth range and dissolved inorganic nutrients were observed. Seagrasses had disappeared over a five-year period near the mouth of the Logan River, a turbid river with increased land use in its watershed. At a site 9 km from the river mouth, a significant decrease in seagrass depth range corresponded to higher light attenuation, chlorophyll a, total suspended solids and total nitrogen content relative to a site 21 km from the river mouth. Seagrass depth penetration thus appears to be a sensitive bio-indicator of some water quality parameters, with application for water quality management.

Evaluation of catchment hydrology and soil loss in non-perennial river system: a case study of Subarnarekha Basin, India

2021 ◽  
Author(s):  
Rituparna Acharyya ◽  
Niloy Pramanick ◽  
Subham Mukherjee ◽  
Subhajit Ghosh ◽  
Abhra Chanda ◽  
...  
Keyword(s):  
Soil Loss ◽  
River System ◽  
Catchment Hydrology ◽  
System A

scholarly journals Studies on picophytoplankton in the southern Gulf of Mexico: recognition of picoprokaryotes and abundances of picophytoplankton during "dry season"

2013 ◽  
Vol 61 (4) ◽  
pp. 265-276 ◽  
Author(s):  
Aldo Aquino-Cruz ◽  
David Uriel Hernández-Becerril ◽  
Martha Signoret-Poillon ◽  
David Alberto Salas-de-León ◽  
María Adela Monreal-Gómez
Keyword(s):  
Gulf Of Mexico ◽  
Chlorophyll A ◽  
River Mouth ◽  
Dry Season ◽  
Shallow Waters ◽  
Southern Gulf Of Mexico ◽  
Lower Maximum ◽  
June July ◽  
Abundance And Distribution ◽  
Three Rivers

The abundance and distribution of total autotrophic picophytoplankton (PFP), temperature, salinity, PAR, and chlorophyll a were determined in two presumably contrasting environments: (1) two coastal areas (close to the mouths of three rivers), and (2) one oceanic area (Campeche Canyon), of the southern Gulf of Mexico, during the "dry season" (June-July, 2004). The picoprokaryotes Prochlorococcus and Synechococcus were identified by TEM, whereas Synechococcus and picoeukaryotes populations were also recognized by flow cytometry. The highest PFP abundance (1.67×105 cells ml-1) was found in shallow waters (~10 m depth) around the Grijalva-Usumacinta river mouth, followed by that found at a station close to the Coatzacoalcos River (1.19×105 cells ml-1); PFP abundances in the Campeche Canyon were usually lower (maximum 1.53×104 cells ml-1). Greater variability in PFP abundances was found in coastal stations than in oceanic waters, and weak relationships appeared between the patterns of chlorophyll a and PFP abundance. Peaks of PFP were detected in both coastal and more oceanic areas, but in the Campeche Canyon they were located deeper (60 m), relatively closer to the deep maximum of chlorophyll (located at about 75 m). Results suggest that PFP populations include a substantial photosynthetic component in both coastal and oceanic waters of the southern Gulf of Mexico.

scholarly journals The Cuito catchment of the Okavango system: a vascular plant checklist for the Angolan headwaters

PhytoKeys ◽  
2018 ◽  
Vol 113 ◽  
pp. 1-31 ◽  
Author(s):  
David J. Goyder ◽  
Nigel Barker ◽  
Stoffel P. Bester ◽  
Arnold Frisby ◽  
Matt Janks ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Conservation Planning ◽  
Vascular Plant ◽  
River System ◽  
Vegetation Types ◽  
Additional Species ◽  
System A ◽  
Peat Deposits ◽  
First Time

This paper aims to provide a baseline for conservation planning by documenting patterns of plant diversity and vegetation in the upper catchment of the Cuito River. 417 species are recorded from this region. Nine of these are species potentially new to science. Ten species are newly recorded from Angola, with an additional species only recorded previously within Angola from the northern enclave of Cabinda. The 108 new provincial records for Moxico clearly indicate the lack of collections from Angola’s largest province. We note the existence of extensive peat deposits in the Cuito river system for the first time and suggest that one of Barbosa’s vegetation types in the area needs to be reassessed.

Can top-down and bottom-up forces explain phytoplankton structure in a subtropical and shallow groundwater-connected lake?

2015 ◽  
Vol 66 (12) ◽  
pp. 1106 ◽  
Author(s):  
Diego Frau ◽  
Melina Devercelli ◽  
Susana José de Paggi ◽  
Pablo Scarabotti ◽  
Gisela Mayora ◽  
...  
Keyword(s):  
Shallow Groundwater ◽  
Resource Limitation ◽  
River System ◽  
High Water ◽  
Taxonomic Resolution ◽  
Dominant Group ◽  
Top Down ◽  
Bottom Up ◽  
Physico Chemical ◽  
Phytoplankton Structure

Bottom-up and top-down control of phytoplankton is one of the most important hypothesis that explains and predicts the structure of aquatic community. Our aim was to elucidate whether predation and resource limitation can control phytoplankton composition and abundance in a subtropical shallow lake with groundwater connection to the river system. During 12 months, the lake was sampled at three points. Physico-chemical parameters, phytoplankton and zooplankton were sampled fortnightly, whereas fish were sampled every 3 months. The results showed that Euglenophyta dominated the total biovolume, followed by Dinophyta and Cryptophyta. As for the species composition, Chlorophyta was the dominant group (80 species recorded), followed by phylum Cyanobacteria (26 species recorded). Redundancy analysis (RDA) indicated that temperature and nitrate + nitrite concentration mainly explained biovolume changes, with zooplankton predation not having any measurable effect on phytoplankton during the high-water (HW) period. During low-water (LW) period top-down by fish was more important. At higher taxonomic resolution (species biovolume), phosphorus was another controlling factor. We concluded that phytoplankton in this lake is mainly regulated by hydrological changes as a macrofactor that affects nutrient availability and other environmental conditions. Even though bottom-up top-down forces do not have a central effect, we found evidence of positive nutrient influences at the HW period and fish effect at the LW period.

Sign in / Sign up

Export Citation Format

Share Document