Total phytoplankton abundance is determined by phosphorus input: evidence from an 18-month fertilization experiment in four subtropical ponds

There is a heated debate over the necessity of nitrogen (N) reduction, in addition to phosphorus (P) reduction, for the control of eutrophication. Whole-lake fertilization experiments and lake restoration practices in high latitudes have demonstrated that P is the primary factor regulating total phytoplankton. Recognizing the limited large-scale evidence in warmer climatic zones, a fertilization experiment was conducted in four ponds located in the subtropical Yangtze River Basin, China. Total phytoplankton abundance in a pond receiving P (+P) was similar to that in a pond receiving both N and P (+N+P). Both had higher phytoplankton than a pond receiving no additional nutrient (Control). Total nitrogen concentration (TN) in the +P pond increased with the appearance of N-fixing cyanobacteria. Total phytoplankton abundance was similar in the ponds without P addition (+N, Control), and both ponds had lower phytoplankton levels than the +N+P pond. These results showed that P, not N, determines total phytoplankton abundance and that N deficiency is offset by N fixation in subtropical lakes. This experiment supports the idea that attention should be mainly focused on P reduction in mitigating eutrophication.

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Risk Assessment and Decision-Making Based on Mean-CVaR-Entropy for Flood Control Operation of Large Scale Reservoirs

Water ◽

10.3390/w11040649 ◽

2019 ◽

Vol 11 (4) ◽

pp. 649 ◽

Cited By ~ 2

Author(s):

Quansen Wang ◽

Jianzhong Zhou ◽

Kangdi Huang ◽

Ling Dai ◽

Gang Zha ◽

...

Keyword(s):

Risk Assessment ◽

Decision Making ◽

Flood Control ◽

Large Scale ◽

Yangtze River Basin ◽

Mean Value ◽

Operation System ◽

Control Operation ◽

Flood Control Operation ◽

Reservoir Flood Control Operation

The risk inevitably exists in the process of flood control operation and decision-making of reservoir group, due to the hydrologic and hydraulic uncertain factors. In this study different stochastic simulation methods were applied to simulate these uncertainties in multi-reservoir flood control operation, and the risk caused by different uncertainties was evaluated from the mean value, extreme value and discrete degree of reservoir occupied storage capacity under uncertain conditions. In order to solve the conflict between risk assessment indexes and evaluate the comprehensive risk of different reservoirs in flood control operation schemes, the subjective weight and objective weight were used to construct the comprehensive risk assessment index, and the improved Mahalanobis distance TOPSIS method was used to select the optimal flood control operation scheme. The proposed method was applied to the flood control operation system in the mainstream and its tributaries of upper reaches of the Yangtze River basin, and 14 cascade reservoirs were selected as a case study. The results indicate that proposed method can evaluate the risk of multi-reservoir flood control operation from all perspectives and provide a new method for multi-criteria decision-making of reservoir flood control operation, and it breaks the limitation of the traditional risk analysis method which only evaluated by risk rate and cannot evaluate the risk of the multi-reservoir flood control operation system.

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Wetland Restoration with Hydrophytes: A Review

Plants ◽

10.3390/plants10061035 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1035

Author(s):

Maria A. Rodrigo

Keyword(s):

Wetland Restoration ◽

Large Scale ◽

Emergent Plants ◽

Filamentous Green Algae ◽

Vital Functions ◽

Climatic Scenarios ◽

Restoration Practices ◽

Natural Wetlands ◽

Sediment Transfer ◽

Negative Factors

Restoration cases with hydrophytes (those which develop all their vital functions inside the water or very close to the water surface, e.g., flowering) are less abundant compared to those using emergent plants. Here, I synthesize the latest knowledge in wetland restoration based on revegetation with hydrophytes and stress common challenges and potential solutions. The review mainly focusses on natural wetlands but also includes information about naturalized constructed wetlands, which nowadays are being used not only to improve water quality but also to increase biodiversity. Available publications, peer-reviewed and any public domain, from the last 20 years, were reviewed. Several countries developed pilot case-studies and field-scale projects with more or less success, the large-scale ones being less frequent. Using floating species is less generalized than submerged species. Sediment transfer is more adequate for temporary wetlands. Hydrophyte revegetation as a restoration tool could be improved by selecting suitable wetlands, increasing focus on species biology and ecology, choosing the suitable propagation and revegetation techniques (seeding, planting). The clear negative factors which prevent the revegetation success (herbivory, microalgae, filamentous green algae, water and sediment composition) have to be considered. Policy-making and wetland restoration practices must more effectively integrate the information already known, particularly under future climatic scenarios.

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Using the Global Hydrodynamic Model and GRACE Follow-On Data to Access the 2020 Catastrophic Flood in Yangtze River Basin

Remote Sensing ◽

10.3390/rs13153023 ◽

2021 ◽

Vol 13 (15) ◽

pp. 3023

Author(s):

Jinghua Xiong ◽

Shenglian Guo ◽

Jiabo Yin ◽

Lei Gu ◽

Feng Xiong

Keyword(s):

River Basin ◽

Hydrodynamic Model ◽

Yangtze River ◽

Large Scale ◽

Yangtze River Basin ◽

The Yangtze River ◽

Ecosystem Monitoring ◽

Catastrophic Flood ◽

Basin Scale ◽

The Yangtze River Basin

Flooding is one of the most widespread and frequent weather-related hazards that has devastating impacts on the society and ecosystem. Monitoring flooding is a vital issue for water resources management, socioeconomic sustainable development, and maintaining life safety. By integrating multiple precipitation, evapotranspiration, and GRACE-Follow On (GRAFO) terrestrial water storage anomaly (TWSA) datasets, this study uses the water balance principle coupled with the CaMa-Flood hydrodynamic model to access the spatiotemporal discharge variations in the Yangtze River basin during the 2020 catastrophic flood. The results show that: (1) TWSA bias dominates the overall uncertainty in runoff at the basin scale, which is spatially governed by uncertainty in TWSA and precipitation; (2) spatially, a field significance at the 5% level is discovered for the correlations between GRAFO-based runoff and GLDAS results. The GRAFO-derived discharge series has a high correlation coefficient with either in situ observations and hydrological simulations for the Yangtze River basin, at the 0.01 significance level; (3) the GRAFO-derived discharge observes the flood peaks in July and August and the recession process in October 2020. Our developed approach provides an alternative way of monitoring large-scale extreme hydrological events with the latest GRAFO release and CaMa-Flood model.

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Factors Enhancing Serum Syndecan-1 Concentrations: A Large-Scale Comprehensive Medical Examination

Journal of Clinical Medicine ◽

10.3390/jcm8091320 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1320

Author(s):

Kazumasa Oda ◽

Hideshi Okada ◽

Akio Suzuki ◽

Hiroyuki Tomita ◽

Ryo Kobayashi ◽

...

Keyword(s):

Large Scale ◽

Prospective Observational Study ◽

Nitrogen Concentration ◽

Laboratory Data ◽

University Hospital ◽

Endothelial Glycocalyx ◽

Sample Collection ◽

Blood Samples ◽

Triglyceride Concentration ◽

Medical Examinations

Endothelial disorders are related to various diseases. An initial endothelial injury is characterized by endothelial glycocalyx injury. We aimed to evaluate endothelial glycocalyx injury by measuring serum syndecan-1 concentrations in patients during comprehensive medical examinations. A single-center, prospective, observational study was conducted at Asahi University Hospital. The participants enrolled in this study were 1313 patients who underwent comprehensive medical examinations at Asahi University Hospital from January 2018 to June 2018. One patient undergoing hemodialysis was excluded from the study. At enrollment, blood samples were obtained, and study personnel collected demographic and clinical data. No treatments or exposures were conducted except for standard medical examinations and blood sample collection. Laboratory data were obtained by the collection of blood samples at the time of study enrolment. According to nonlinear regression, the concentrations of serum syndecan-1 were significantly related to age (p = 0.016), aspartic aminotransferase concentration (AST, p = 0.020), blood urea nitrogen concentration (BUN, p = 0.013), triglyceride concentration (p < 0.001), and hematocrit (p = 0.006). These relationships were independent associations. Endothelial glycocalyx injury, which is reflected by serum syndecan-1 concentrations, is related to age, hematocrit, AST concentration, BUN concentration, and triglyceride concentration.

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Effects of CO<sub>2</sub> on particle size distribution and phytoplankton abundance during a mesocosm bloom experiment (PeECE II)

Biogeosciences ◽

10.5194/bg-5-509-2008 ◽

2008 ◽

Vol 5 (2) ◽

pp. 509-521 ◽

Cited By ~ 85

Author(s):

A. Engel ◽

K. G. Schulz ◽

U. Riebesell ◽

R. Bellerby ◽

B. Delille ◽

...

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Large Scale ◽

Phytoplankton Community ◽

Co2 Enrichment ◽

Suspended Particles ◽

Phytoplankton Abundance ◽

General Importance ◽

Co2 Treatment

Abstract. The influence of seawater carbon dioxide (CO2) concentration on the size distribution of suspended particles (2–60 μm) and on phytoplankton abundance was investigated during a mesocosm experiment at the large scale facility (LFS) in Bergen, Norway, in the frame of the Pelagic Ecosystem CO2 Enrichment study (PeECE II). In nine outdoor enclosures the partial pressure of CO2 in seawater was modified by an aeration system to simulate past (~190 μatm CO2), present (~370 μatm CO2) and future (~700 μatm CO2) CO2 conditions in triplicates. Due to the initial addition of inorganic nutrients, phytoplankton blooms developed in all mesocosms and were monitored over a period of 19 days. Seawater samples were collected daily for analysing the abundance of suspended particles and phytoplankton with the Coulter Counter and with Flow Cytometry, respectively. During the bloom period, the abundance of small particles (<4 μm) significantly increased at past, and decreased at future CO2 levels. At that time, a direct relationship between the total-surface-to-total-volume ratio of suspended particles and DIC concentration was determined for all mesocosms. Significant changes with respect to the CO2 treatment were also observed in the phytoplankton community structure. While some populations such as diatoms seemed to be insensitive to the CO2 treatment, others like Micromonas spp. increased with CO2, or showed maximum abundance at present day CO2 (i.e. Emiliania huxleyi). The strongest response to CO2 was observed in the abundance of small autotrophic nano-plankton that strongly increased during the bloom in the past CO2 mesocosms. Together, changes in particle size distribution and phytoplankton community indicate a complex interplay between the ability of the cells to physiologically respond to changes in CO2 and size selection. Size of cells is of general importance for a variety of processes in marine systems such as diffusion-limited uptake of substrates, resource allocation, predator-prey interaction, and gravitational settling. The observed changes in particle size distribution are therefore discussed with respect to biogeochemical cycling and ecosystem functioning.

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

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652011000400018 ◽

2011 ◽

Vol 83 (4) ◽

pp. 1313-1326 ◽

Cited By ~ 9

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.

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Searching for the bottom of the ego well: Failure to uncover ego depletion in Many Labs 3

10.31234/osf.io/ja2kb ◽

2017 ◽

Author(s):

Miguel A. Vadillo ◽

Natalie Gold ◽

Magda Osman

Keyword(s):

Stroop Task ◽

Secondary Task ◽

Large Scale ◽

Limited Resource ◽

Ego Depletion ◽

Self Control ◽

Significant Evidence ◽

Heated Debate ◽

The Subject ◽

Optimal Measure

According to a popular model of self-control, willpower depends on a limited resource that can be depleted when we perform a task demanding self-control. Over the last five years, the reliability of the empirical evidence supporting this model has become the subject of heated debate. In the present study, we reanalysed data from a large-scale study –Many Labs 3– to test whether performing a depleting task has any effect on a secondary task that also relies on self-control. Although we used a large sample of more than 2,000 participants for our analyses, we did not find any significant evidence of ego-depletion: Persistence on an anagram solving task (a typical measure of self-control) was not affected by previous completion of a Stroop task (a typical depleting task in this literature). Our results suggest that persistence in anagram solving may not be an optimal measure to test depletion effects.

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Mycorrhizal fungal community relationship to root nitrogen concentration over a regional atmospheric nitrogen deposition gradient in the northeastern USA

Canadian Journal of Forest Research ◽

10.1139/x07-211 ◽

2008 ◽

Vol 38 (5) ◽

pp. 1260-1266 ◽

Cited By ~ 22

Author(s):

Erik A. Lilleskov ◽

Philip M. Wargo ◽

Kristiina A. Vogt ◽

Daniel J. Vogt

Keyword(s):

Large Scale ◽

Spatial Scales ◽

Nitrogen Concentration ◽

N Deposition ◽

Small Scale ◽

N Availability ◽

Cenococcum Geophilum ◽

Ectomycorrhizal Morphotypes ◽

Deposition Gradient ◽

Northeastern Usa

Increased nitrogen (N) input has been found to alter ectomycorrhizal fungal communities over short deposition gradients and in fertilization experiments; however, its effects over larger spatial scales have not been determined. To address this gap, we reanalyzed data from a study originally designed to examine the effects of soil aluminum/calcium (Al/Ca) ratios on the vitality of red spruce fine roots over a regional acid and N deposition gradient in the northeastern USA. We used root N as an indicator of stand N availability and examined its relationship with the abundance of ectomycorrhizal morphotypes. The dominant morphotypes changed in relative abundance as a function of stand N availability. As root N concentrations increased, Piloderma spp. - like, Cenococcum geophilum Fr., and other unidentified mycorrhizal morphotypes declined in abundance, while other smooth-mantled morphotypes increased. Root N concentration in the 1–2 mm diameter class was the best predictor of the abundance of multiple morphotypes. The morphotype responses were consistent with those found in experimental and small-scale studies, suggesting that N availability is altering ectomycorrhizal communities over broad spatial scales in this region. This finding provides an impetus to conduct a more detailed characterization of mycorrhizal community responses to N deposition across large-scale gradients.

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Rapid evaluation of pasture quality for a critically endangered mammal, the northern hairy-nosed wombat (Lasiorhinus krefftii)

Wildlife Research ◽

10.1071/wr00050 ◽

2002 ◽

Vol 29 (1) ◽

pp. 91 ◽

Cited By ~ 10

Author(s):

Andrew P. Woolnough ◽

William J. Foley

Keyword(s):

Large Scale ◽

Nutritive Value ◽

Near Infrared ◽

Nitrogen Concentration ◽

Water Soluble ◽

Critically Endangered ◽

Soluble Carbohydrates ◽

Dry Matter Digestibility ◽

Acid Detergent Fibre

Near-infrared spectroscopy (NIRS) was used to predict the nutritive value of forage species available to the critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii). Nutritive attributes of the forage successfully estimated included total nitrogen concentration, fibre (including neutral detergent fibre, acid detergent fibre and acid lignin), organic matter, water soluble carbohydrates and in vitro dry matter digestibility. The reported results demonstrate the seasonal variability of the forage resource available to L. krefftii in its tropical savanna habitat. Multivariate modelling of the spectra enabled the nutritive value of forage samples to be estimated with coefficients of determination (r2) of 0.770–0.995 and standard errors of the cross-validation of 0.070–2.850 using a modified partial least-squares analysis technique. The standard error of the laboratory was 0.02–1.42. This study demonstrates that broad-based NIRS predictive equations can be used to predict the nutritive value of a number of plant types available to a herbivore over time. By using NIRS the analyst can rapidly analyse large numbers of samples with limited reduction of precision, thereby enabling large-scale ecological applications that may have previously been impeded by time and costs.

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Confocal Microscopy in Ecophysiological Studies of Algae: A Door to Understanding Autofluorescence in Red Algae

Microscopy and Microanalysis ◽

10.1017/s1431927621013660 ◽

2021 ◽

pp. 1-9

Author(s):

Teresa Coronado-Parra ◽

Mónica Roldán ◽

Marina Aboal

Keyword(s):

Laser Scanning ◽

Large Scale ◽

Nitrogen Concentration ◽

Monochromatic Light ◽

Environmental Parameters ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Scale Production ◽

Light Intensities

Alga in the genus Chroothece have been reported mostly from aquatic or subaerial continental environments, where they grow in extreme conditions. The strain Chroothece mobilis MAESE 20.29 was exposed to different light intensities, red and green monochromatic light, ultraviolet (UV) radiation, high nitrogen concentrations, and high salinity to assess the effect of those environmental parameters on its growth. Confocal laser scanning microscopy (CLSM) was used as an “in vivo” noninvasive single-cell method for the study. The strain seemed to prefer fairly high light intensities and showed a significant increase in allophycocyanin (APC) and chlorophyll a [photosystem I (PSI) and photosystem II (PSII)] fluorescence with 330 and 789 μM/cm2/s intensities. Green monochromatic light promoted a significant increase in the fluorescence of APC and chlorophyll a (PSI and PSII). UV-A significantly decreased phycocyanin and increased APC, while UV-A + B showed a greater decreasing effect on c-Phycocyanin but did not significantly change concentrations of APC. The increase in nitrogen concentration in the culture medium significantly and negatively affected all pigments, and no effect was observed with an increase in salinity. Our data show that CLSM represents a very powerful tool for ecological research of microalgae in small volumes and may contribute to the knowledge of phycobiliproteins in vivo behavior and the parameters for the large-scale production of these pigments.

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