scholarly journals Long-Term Variations in Chlorophyllaand Primary Productivity in Jiaozhou Bay, China

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Baodong Wang ◽  
Zongling Wang
Keyword(s):  
Primary Productivity ◽  
Linear Response ◽  
Phytoplankton Biomass ◽  
Jiaozhou Bay ◽  
Zooplankton Biomass ◽  
Nutrient Concentrations ◽  
Period Analysis ◽  
Term Data ◽  
Long Term Variations

Based on long-term data of measurements of nutrient and chlorophyllaconcentrations as well as estimates of primary production, the response of phytoplankton to nutrient enrichment was evaluated in the highly urbanized Jiaozhou Bay. Results showed that phytoplankton biomass, as indicated by chlorophyllaconcentration, did not show a direct linear response to increased nutrient concentrations. Instead, chlorophyllaconcentration was maintained at a constant level in the last two decades in Jiaozhou Bay, so did primary productivity. However, a reduction of zooplankton biomass was observed during the same period. Analysis showed that although the scale of phytoplankton blooms might be limited by availability of silicate due to low Si/N ratio and low concentration, top-down control on phytoplankton biomass by bivalve grazing may be an important factor in Jiaozhou Bay ecosystem.

Evaluation of factors related to increased zooplankton biomass and altered species composition following impoundment of a Newfoundland reservoir

1998 ◽  
Vol 55 (1) ◽  
pp. 230-238 ◽  
Author(s):  
Christine E Campbell ◽  
Roy Knoechel ◽  
Douglas Copeman
Keyword(s):  
Species Composition ◽  
Primary Productivity ◽  
Retention Time ◽  
Phytoplankton Biomass ◽  
Water Retention ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Nutrient Concentrations ◽  
Water Retention Time ◽  
Daphnia Catawba

Zooplankton biomass and species composition were monitored in Cat Arm Lake and Reservoir on Newfoundland's Great Northern Peninsula from 1983 to 1993. Zooplankton biomass increased approximately 19-fold in the oligotrophic reservoir following impoundment in 1984, relative to biomass in the preexisting lake. Microcrustaceans Cyclops scutifer and Daphnia dubia, either rare or absent from Cat Arm Lake prior to impoundment, were consistently measurable components of the zooplankton community by 1993. Similar changes elsewhere have been attributed to both increased water retention time and enhanced phytoplankton biomass, factors whose effects are usually interdependent. In Cat Arm, there were no increases in either phytoplankton biomass or primary productivity during the first 3 years of impoundment, and natality of the dominant cladoceran, Daphnia catawba, did not increase. Summer water retention time increased from preimpoundment levels of 4 days in 1983 to 338 days in 1993. Zooplankton biomass was significantly correlated with water retention time (Spearman's rs = 0.72, p = 0.04) and showed no significant correlation with phytoplankton biomass, primary productivity, nutrient concentrations, pH, colour, or epilimnetic temperature. Changes in the zooplankton community in this subarctic system can thus be attributed most directly to a decrease in losses due to washout.

scholarly journals Long-term effects of temperature and nutrient concentrations on the phytoplankton biomass in three lakes with differing trophic statuses on the Yungui Plateau, China

2018 ◽  
Vol 54 ◽  
pp. 9 ◽  
Author(s):  
Jing Dong ◽  
Qichao Zhou ◽  
Yunni Gao ◽  
Qianhong Gu ◽  
Genbao Li ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Algal Biomass ◽  
Nutrient Concentrations ◽  
Long Term Effects ◽  
Lake Dianchi ◽  
Lake Fuxian ◽  
Key Factor ◽  
Lake Erhai ◽  
Increasing Temperature

Long-term annual (1990–2010) monitoring data were analyzed to test the responses of phytoplankton biomass in three lakes in the Yungui Plateau, China, to increasing temperature and increasing nutrient concentrations. The three studied lakes (Lake Fuxian, Lake Erhai and Lake Dianchi) all exhibited significant increases in algal biomass from 1990 to 2010, with increases of 0.111 µg/L, 0.662 µg/L and 3.07 µg/L per year, respectively. The study also indicated that the relative influences of warming and nutrient concentrations on chlorophyll a concentration varied among the lakes and was dependent on trophic level and phytoplankton composition. In Lake Fuxian, the increase in algal biomass was correlated with the rapid growth of Mougeotia spp., and the total phosphorous concentration was the key factor driving this increase in algal biomass. In Lake Erhai, the dominant species shifted from Dolichospermum spp. to Microcystis spp. Additionally, the increase in algal biomass in Lake Erhai (involving mainly an increase in Microcystis spp.) was significantly associated with an increase in total nitrogen (TN) concentration. In Lake Dianchi, warming and increases in TN concentration were the strongest predictors of biomass change.

Importance of Latitude and Organic Color on Phytoplankton Primary Productivity in Florida Lakes

1991 ◽  
Vol 48 (7) ◽  
pp. 1145-1150 ◽  
Author(s):  
John R. Beaver ◽  
Thomas L. Crisman
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Phytoplankton Biomass ◽  
Nutrient Concentrations ◽  
Empirical Equations ◽  
Strongly Correlated ◽  
Florida Lakes ◽  
Vegetative Season

A characterization of primary productivity patterns in subtropical Florida lakes along increasing gradients of both dissolved organic color and phytoplankton biomass is presented. Volumetric expression of gross primary productivity was more strongly correlated with chlorophyll a and nutrient concentrations than was areal expression. Primary production in clearwater (<75 Pt units) lakes was more predictable than colored (>75 Pt units) lakes. Areal production in Florida lakes was intermediate to the tropical and temperate regions, although volumetric productivity during the vegetative season (May–September) was not significantly different from temperate zone lakes for the same period. Predictive abilities of empirical equations describing primary productivity in Florida lakes are improved by distinguishing colored and clear lakes.

The water masses of the east coast of Tasmania: Seasonal and interannual variability and the influence on phytoplankton biomass and productivity

1987 ◽  
Vol 38 (5) ◽  
pp. 569 ◽  
Author(s):  
G Harris ◽  
C Nilsson ◽  
L Clementson ◽  
D Thomas
Keyword(s):  
Interannual Variability ◽  
Primary Productivity ◽  
Phytoplankton Biomass ◽  
Seasonal Cycle ◽  
East Coast ◽  
Spring Bloom ◽  
Water Masses ◽  
Seasonal And Interannual Variability ◽  
Summer Temperatures

The seasonal and interannual variability of the water masses, nutrients, phytoplankton biomass and primary productivity of the waters off the eastern coast of Tasmania are described. The seasonal and interannual variability in the water masses on the east coast could be explained by the varying influence of tropical and subantarctic waters and the presence of the northern edge of the subtropical convergence north-east from Maria Island. The physical oceanography was dominated by mesoscale events and the influence of the two parent water masses was highly episodic. Subtropical water rarely extended as far south as Tasman Island in summer and subantarctic water never extended as far north as Flinders Island. Data from satellite Advanced Very High Resolution Radiometer (AVHRR) images confirmed the hydrographic data and were used to interpret the seasonal and interannual variability. Interannual variability in maximum summer temperatures at Maria Island was correlated with the southerly extension of subtropical waters and with El Nino/Southern Oscillation events at least until the mid-1970s. There was evidence of a long-term warming at Maria Island and a cyclic fluctuation of 10-15 years in smoothed maximum summer temperatures. The decline in nitrate, and hence the phytoplankton spring bloom, occurred a month earlier inshore than offshore. Long-term data records from the inshore station at Maria Island showed strong interannual changes in the timing of the nitrate decline. The timing of the spring bloom varied from year to year by as much as 4 months. The seasonal cycle of phytoplankton biomass in 1984 and 1985 showed spring (October) and autumnal (April) blooms, with an early summer bloom in December. Low chlorophyll levels in February and March coincided with the influence of subtropical water. The seasonal cycle of phytoplankton biomass was therefore a complex function of seasonal and episodic events. Primary productivity data from the spring of 1984 showed low productivity on the west coast of Tasmania but high productivity on the east coast around Maria Island and the islands in Bass Strait.

scholarly journals Scale issues for assessment of nutrient leaching from agricultural land in Latvia

2012 ◽  
Vol 43 (4) ◽  
pp. 383-399 ◽  
Author(s):  
Ainis Lagzdins ◽  
Viesturs Jansons ◽  
Ritvars Sudars ◽  
Kaspars Abramenko
Keyword(s):  
Water Quality ◽  
Classification System ◽  
Agricultural Land ◽  
Pollution Monitoring ◽  
Nutrient Concentrations ◽  
Total N ◽  
Small Catchment ◽  
Total P ◽  
Term Data

This paper deals with water quality assessment and recommendations for a classification system based on nitrogen (N) and phosphorus (P) concentrations. In order to evaluate the influence of agricultural intensity, climate and hydrology on water quality, the long-term data (from 1995 to 2009) collected in three Latvian diffuse pollution monitoring sites (Berze, Mellupite and Vienziemite) were analysed. Measurements were carried out within areas where agriculture was the main source of diffuse nutrient loading at four spatial scales, i.e. experimental plot, drainage field, small catchment and river. The available long-term data series shows large variations in nutrient concentrations, depending on the intensity of agricultural production system and the scale of measurements. The concentrations of total N are higher at the plot scale, decreasing when the spatial scale of measurements increase. The proposed simplified classification system (five classes) was based upon the assumption that good chemical status for rivers in agricultural areas represent concentrations of total N &lt; 1.5 mg L−1 and total P &lt; 0.075 mg L−1, while in small catchments total N &lt; 2.5 mg L−1 and total P &lt; 0.050 mg L−1 and in subsurface drainage water total N &lt; 5.5 mg L−1 and total P &lt; 0.020 mg L−1.

Long-term variations of the riverine input of potentially toxic dissolved elements and the impacts on their distribution in Jiaozhou Bay, China

2018 ◽  
Vol 25 (9) ◽  
pp. 8800-8816 ◽  
Author(s):  
Changyou Wang ◽  
Jinqiang Guo ◽  
Shengkang Liang ◽  
Yunfei Wang ◽  
Yanqun Yang ◽  
...  
Keyword(s):  
Jiaozhou Bay ◽  
Riverine Input ◽  
Long Term Variations

scholarly journals Causes of simulated long-term changes in phytoplankton biomass in the Baltic proper: a wavelet analysis

2018 ◽  
Vol 15 (16) ◽  
pp. 5113-5129 ◽  
Author(s):  
Jenny Hieronymus ◽  
Kari Eilola ◽  
Magnus Hieronymus ◽  
H. E. Markus Meier ◽  
Sofia Saraiva ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Mixed Layer ◽  
Temperature Increase ◽  
Phytoplankton Biomass ◽  
Mixed Layer Depth ◽  
Circulation Model ◽  
Nutrient Concentrations ◽  
Baltic Proper ◽  
The Baltic

Abstract. The co-variation of key variables with simulated phytoplankton biomass in the Baltic proper has been examined using wavelet analysis and results of a long-term simulation for 1850–2008 with a high-resolution coupled physical–biogeochemical circulation model for the Baltic Sea. By focusing on inter-annual variations, it is possible to track effects acting on decadal timescales such as temperature increase due to climate change as well as changes in nutrient input. The strongest inter-annual coherence indicates that variations in phytoplankton biomass are determined by changes in concentrations of the limiting nutrient. However, after 1950 high nutrient concentrations created a less-nutrient-limited regime, and the coherence was reduced. Furthermore, the inter-annual coherence of mixed-layer nitrate with riverine input of nitrate is much larger than the coherence between mixed-layer phosphate and phosphate loads. This indicates a greater relative importance of the vertical flux of phosphate from the deep layer into the mixed layer. In addition, shifts in nutrient patterns give rise to changes in phytoplankton nutrient limitation. The modelled pattern shifts from purely phosphate limited to a seasonally varying regime. The results further indicate some effect of inter-annual temperature increase on cyanobacteria and flagellates. Changes in mixed-layer depth affect mainly diatoms due to their high sinking velocity, while inter-annual coherence between irradiance and phytoplankton biomass is not found.

Hydrogeological responses in tropical mountainous springs

2019 ◽  
Author(s):  
Ricardo Sánchez-Murillo
Keyword(s):  
Costa Rica ◽  
Isotope Composition ◽  
Central Valley ◽  
Distribution Functions ◽  
Geochemical Composition ◽  
Transit Times ◽  
Management Plans ◽  
Best Fit ◽  
Term Data

This study presents a hydrogeochemical analysis of spring responses (2013-2017) in the tropical mountainous region of the Central Valley of Costa Rica. The isotopic distribution of δ18O and δ2H in rainfall resulted in a highly significant meteoric water line: δ2H = 7.93×δ18O + 10.37 (r2=0.97). Rainfall isotope composition exhibited a strong dependent seasonality. The isotopic variation (δ18O) of two springs within the Barva aquifer was simulated using the FlowPC program to determine mean transit times (MTTs). Exponential-piston and dispersion distribution functions provided the best-fit to the observed isotopic composition at Flores and Sacramento springs, respectively. MTTs corresponded to 1.23±0.03 (Sacramento) and 1.42±0.04 (Flores) years. The greater MTT was represented by a homogeneous geochemical composition at Flores, whereas the smaller MTT at Sacramento is reflected in a more variable geochemical response. The results may be used to enhance modelling efforts in central Costa Rica, whereby scarcity of long-term data limits water resources management plans.

Morphometric studies of artemia males from different populations of the Altai region

2020 ◽  
pp. 28-38
Author(s):  
L. Vesnina ◽  
G. Lukerina ◽  
T. Ronzhina ◽  
A. Savos’kin ◽  
D. Surkov
Keyword(s):  
Sexual Dimorphism ◽  
Hydrogen Index ◽  
Morphometric Parameters ◽  
Altai Region ◽  
Sexual Structure ◽  
Different Populations ◽  
Artemia Population ◽  
Term Data ◽  
Brine Salinity

The long-term data from morphometric studies of Artemia males from bisexual and parthenogenetic populations from hyperhaline reservoirs of the Altai region (Bolshoe Yarovoe Lake, Maloe Shklo Lake, and the Tanatar Lakes system) is analyzed in this paper. The description of signs of sexual dimorphism and sexual structure in different populations is given. The influence of brine salinity and hydrogen index on morphometric parameters of males was analyzed. There are differences in the sexual structure of the Artemia population: in the lakes Maloe Shklo and the thanatar system, the populations are bisexual (the share of males is 28.5 — 75.0 %), in the lake Bolshoe yarovoe — parthenogenetic (the share of males on average does not exceed 3 %). At the same time, sexual dimorphism is typical for both types of populations: females are larger than males, males have a larger head (the distance between the eyes is greater by 15.5 %, the diameter of the eye is 26.1 %, the length of the antenna is 22.3 %) and a larger number of bristles (36.1 %). The greatest variability is observed in the parameters of the Furka structure associated with the salinity of water by feedback and the pH — line indicator. Significant differences between the samples of males were revealed. The largest number of significant differences in morphometric indicators was found between samples of males from bisexual populations (lake thanatar and lake Maloe Shklo), the smallest — between males from the parthenogenetic population of lake Bolshoe yarovoe and males from lake Maloe Shklo.

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