scholarly journals Investigating possible causal relations among physical, chemical and biological variables across regions in the Gulf of Maine

Hydrobiologia ◽  
2014 ◽  
Vol 744 (1) ◽  
pp. 127-143 ◽  
Author(s):  
Knut L. Seip
Keyword(s):  
Gulf Of Maine ◽  
Causal Relations ◽  
Biological Variables ◽  
Physical Chemical

scholarly journals Effects of Weir Construction on Phytoplankton Assemblages and Water Quality in a Large River System

2018 ◽  
Vol 15 (11) ◽  
pp. 2348 ◽  
Author(s):  
Hae-Jin Lee ◽  
Hae-Kyung Park ◽  
Se-Uk Cheon
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
River System ◽  
Large River ◽  
Anthropogenic Factors ◽  
Centric Diatom ◽  
Nakdong River ◽  
Biological Variables ◽  
Physical Chemical ◽  
The Nakdong River

Flow regulation is one of the most common anthropogenic factors affecting rivers worldwide. In Korea, 16 weirs were constructed along four major rivers from 2009 to 2012. This study aimed to elucidate initial changes in physical, chemical, and biological variables after the construction of consecutive weirs on the Nakdong River, a major large river system. Water quality variables and phytoplankton cell densities were investigated at eight representative sites and compared with the data recorded before the weir construction. There were spatial and temporal changes in the hydraulic retention time (HRT), total phosphorus (TP), and chlorophyll a concentrations among the eight weir sections. HRT increased after the weir construction, while TP and chlorophyll a tended to decrease from the middle to lower section of the Nakdong River. Furthermore, differences were observed in the phytoplankton community composition between 2006–2007 and 2013. There was a marginal decrease in the duration of centric diatom (Stephanodiscus hantzschii) blooms after weir construction. However, Microcystis aeruginosa proliferated more extensively during summer and autumn than it did before the weir construction. Our results suggest that changes in hydrological factors, in response to consecutive weir construction, may contribute to greater physical, chemical, and ecological variability.

scholarly journals The response of Carlos Botelho (Lobo, Broa) reservoir to the passage of cold fronts as reflected by physical, chemical, and biological variables

2004 ◽  
Vol 64 (1) ◽  
pp. 177-186 ◽  
Author(s):  
J. G. Tundisi ◽  
T. Matsumura-Tundisi ◽  
J. D. Arantes Junior ◽  
J. E. M. Tundisi ◽  
N. F. Manzini ◽  
...  
Keyword(s):  
Management Strategies ◽  
Vertical Mixing ◽  
Continuous System ◽  
Cyanobacterial Blooms ◽  
Metropolitan Region ◽  
Climatological Data ◽  
Cold Fronts ◽  
Biological Variables ◽  
Physical Chemical ◽  
Shallow Reservoirs

This paper describes and discusses the impacts of the passage of cold fronts on the vertical structure of the Carlos Botelho (Lobo-Broa) Reservoir as demonstrated by changes in physical, chemical, and biological variables. The data were obtained with a continuous system measuring 9 variables in vertical profiles in the deepest point of the reservoir (12 m) coupled with climatological information and satellite images, during a 32-day period in July and August, 2003. During periods of incidence of cold fronts the reservoir presented vertical mixing. After the dissipation of the cold fronts a period of stability followed with thermal, chemical, and biological (chlorophyll-a) stratification. Climatological data obtained during the cold front passage showed lower air temperature, higher wind speed and lower solar radiation. The response of this reservoir can exemplify a generalized process in all shallow reservoirs in the Southeast Brazil and could have several implications for management, particularly in relation to the phytoplankton population dynamics and development of cyanobacterial blooms. Using this as a basis, a predictive model will be developed with the aim of advancing management strategies specially for the drinking water reservoirs of the Metropolitan Region of São Paulo.

The response of reservoirs of southeastern Brazil to the passage of cold fronts as reflected by physical, chemical and biological variables

2006 ◽  
Vol 29 (4) ◽  
pp. 2124-2128
Author(s):  
J.G. Tundisi ◽  
N.Y. Sebastien ◽  
T. Matsumura-Tundisi ◽  
J.E.M. Tundisi ◽  
N.F. Manzini
Keyword(s):  
Southeastern Brazil ◽  
Cold Fronts ◽  
Biological Variables ◽  
Physical Chemical

scholarly journals Evaluación, Física, Química y Biológica de compostas tipo bocashi elaboradas con estiércol de bovino, ovino, cerdo y conejo más una vermicomposta

2019 ◽  
pp. 33-40
Author(s):  
Alicia De Luna-Vega ◽  
María Luisa García-Sahagún ◽  
Enrique Pimienta-Barrios ◽  
Eduardo Rodríguez-Guzmán
Keyword(s):  
Seed Germination ◽  
Root Development ◽  
Indoleacetic Acid ◽  
Biological Variables ◽  
Physical Chemical ◽  
Minimum Requirements ◽  
Agronomic Quality ◽  
Organic Compost

Some composts can produce phytotoxins that inhibit the development of plants and the absorption of nutrients by an excess of indoleacetic acid if the compost is not mature. In the present work, the objective is to evaluate the quality of the compost by means of direct tests of phytotoxicity and agronomic quality with different composts. To determine the quality as organic compost and vermicompost fertilizer were considered physical, chemical and biological variables according to existing manuals. The results obtained for these variables were: In the physical, chemical and biological variables, all the parameters are fulfilled according to the norm. Seed germination of vegetables increased with respect to the control in 14.93%, possibly due to the presence of some root development promoter found in the compost. With regard to survival the witness was inferior by 3.08% Although the amount of nutrients found in composts are not so high, they comply with the minimum requirements of the regulations to be used as a substrate in horticultural applications. Conclusion, the results of this study indicate that the compost elaborated with any type of residue can be used as a substrate in seedbeds of chili, onion or other vegetables to induce germination and accelerate the development of plants.

scholarly journals RELACIONES CONTEMPORANEAS Y REZAGADAS ENTRE VARIABLES FISICOQUIMICAS Y BIOLOGICAS EN LA CIENAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

2016 ◽  
Vol 27 ◽  
Author(s):  
Sven Zea ◽  
Ramón Giraido H. ◽  
José Ernesto Mancera P ◽  
Jorge Martínez C.
Keyword(s):  
Primary Production ◽  
Total Nitrogen ◽  
Phytoplankton Biomass ◽  
Apparent Lack ◽  
Biological Variables ◽  
Physical Chemical ◽  
Generation Times ◽  
Mean And Variance ◽  
Cross Correlations ◽  
Time Lagged

From available data from four sampling stations at Ciénaga Grande de Santa Marta coastal lagoon (Colombian Caribbean), contemporary and time-lagged cross-correlations between biweekly series of "biological" variables (chrolophyll a, primary productivity) and "physical-chemical" variables (salinity, transparency, inorganic nutrientes, total nitrogen and phosphorous, phaeopigments, seston proteins) were explored. In contrast with the original analyses, turning series stationary (constant mean and variance) eliminated variations in trend and magnitude associated with climate, and emphasized variation at the scale of weeks. As a result, changes in primary production were not related either with contemporary changes in phytoplankton biomass (measured as chlorophyll a) or with previous or contemporary changes in physical chemical variables. This apparent lack of effect of the inorganic nutrients regime on the primary production may occur because nutrient availability is the dinamyc result of uptake and recycling. Only, increases in total nitrogen were associated with rises in primary production 4 weeks later, possibly from lagged used of reserves by phytoplankton. Variations in phytoplankton biomass were positively correlated with contemporary changes in dissolved phosphorous, and negatively with changes in transparency. The first relation could be caused by phosphorous liberation from the benthos in nocturnal anoxic conditions during massive blooms. The second may occur because the main agent conditioning water transparency is phytoplankton. In contrast, increases in primary production were followed by decreases in dissolved nitrogen and phosphorous two weeks later, again possibly in relation to phytoplankton generation times and the dynamics of uptake and recycling.

scholarly journals Causal inference using deep-learning variable selection identifies and incorporates direct and indirect causalities in complex biological systems

2021 ◽  
Author(s):  
Zhenjiang Fan ◽  
Kate F Kernan ◽  
Panayiotis V Benos ◽  
Gregory F Cooper ◽  
Scott W Canna ◽  
...  
Keyword(s):  
Deep Learning ◽  
Variable Selection ◽  
Causal Inference ◽  
Causal Structure ◽  
Complex Diseases ◽  
Therapeutic Agents ◽  
Causal Learning ◽  
Biological Data ◽  
Causal Relations ◽  
Biological Variables

In complex diseases, causal structure learning across biological variables is critical to identify modifiable triggers or potential therapeutic agents. A limitation of existing causal learning methods is that they cannot identify indirect causal relations, those that would interact through latent mediating variables. We developed the first computational method that identifies both direct and indirect causalities, causal inference using deep-learning variable-selection (causalDeepVASE). To accurately identify indirect causalities and incorporate them with direct causalities, causalDeepVASE develops a deep neural network approach and extends a flexible causal inference method. In simulated and biological data of various contexts, causalDeepVASE outperforms existing methods in identifying expected or validated causal relations. Further, causalDeepVASE facilitates a systematic understanding of complex diseases. For example, causalDeepVASE uniquely identified a possible causal relation between IFNγ and creatinine suggested in a polymicrobial sepsis model. In future biomedical studies, causalDeepVASE can facilitate the identification of driver genes and therapeutic agents.

scholarly journals Longitudinal processes in Salto Grande reservoir (Americana, SP, Brazil) and its influence in the formation of compartment system

2002 ◽  
Vol 62 (2) ◽  
pp. 347-361 ◽  
Author(s):  
L. H. ZANATA ◽  
E. L. G. ESPÍNDOLA
Keyword(s):  
Longitudinal Axis ◽  
Chemical Oxidation ◽  
Sampling Station ◽  
Longitudinal Gradient ◽  
Compartment System ◽  
Rainy Period ◽  
Operational Mechanism ◽  
Biological Variables ◽  
Physical Chemical ◽  
Concentration Degree

Studies on the longitudinal processes in reservoirs, involving physical, chemical and biological processes have been thoroughly appraised, suggesting the existence of a longitudinal organization controlled by the entrance and circulation of water which inserts modifications in the structuring of the system. To evaluate this effect, the Salto Grande reservoir (Americana, SP) was analyzed in 11 sampling stations in its longitudinal axis, in the rainy and dry seasons of 1997 considering the physical chemical and biological variables. Analyzing the results in agreement with the declining concentration degree of the river--barrage direction, a more significant correlation was verified in the dry period for total phosphorus (r² = 0.86), dissolved total phosphate (r² = 0.83), nitrite (r² = 0.93), inorganic phosphate (r² = 0.89), ammonium (r² = 0.84) and suspended material (r² = 0.85). In the rainy period, only nitrite (r² = 0.90) and conductivity (r² = 0.89) presented correlation with the distance of the dam, which demonstrates the effects of precipitation and the operational mechanism of the dam, as well as the distinction among the physical (sedimentation), chemical (oxidation) and biological (decomposition) processes in spatial heterogeneity of the system. These factors were decisive in the organization of these communities, with higher occurrence of rotifers and copepods in relation to cladocerans, the first ones being more abundant in the entrance of the Atibaia river, decreasing towards the dam direction, while copepods presented an inverse pattern. A distribution pattern similar to Copepoda was also verified for the Cladocera, evidencing a tendency to increase the density of organisms in the stations distant to the entrance of the Atibaia river, not being registered, however, a distribution gradient in the longitudinal axis, as observed for rotifers and copepods. In relation to the trophic degree a longitudinal gradient was also verified from eutrophic to oligotrophic depending on the location of the sampling station in relation to the longitudinal axis and period of analysis. The differences obtained, relating to the distribution of the environmental variables, demonstrate a characteristic pattern for reservoirs, with a longitudinal gradient in the sense river--barrage that inserts changes in the physical and chemical composition of the water, contributing to the differentiated establishing of biological communities.

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Fisheries Management ◽  
Management Practices ◽  
Gulf Of Maine ◽  
Monitoring Program ◽  
Ecosystem Approach ◽  
Environmental Data ◽  
Biological Variables ◽  
Assessment Approach ◽  
New Research ◽  
Science Symposium

<i>Abstract</i>.—This chapter summarizes contributions to a theme session of the 2009 Gulf of Maine Science Symposium held in St. Andrew’s, New Brunswick in October, 2009. The session highlighted the present status of science required to observe, interpret, and predict changes in the Gulf of Maine ecosystem in the context of strategies for regional implementation of an ecosystem approach to management (EAM). Perspectives on present ecosystem approaches to Gulf of Maine fisheries management contrast the integrated ecosystem assessment approach by the U.S. National Oceanic and Atmospheric Administration, with the more incremental advancement to EAM based on traditional fisheries management practices undertaken by Fisheries and Oceans Canada. A section on contributions from the broader research community provides perspectives on observations and different approaches to analysis, including coupled physical biological modeling as a tool for the integration, interpretation, and prediction of multidisciplinary environmental data. The Atlantic Zonal Monitoring Program has established an observing system for physical and biological characteristics of Canadian coastal waters, and NERACOOS (the Northeast Regional Association of Coastal Ocean Observing Systems) is developing infrastructure for coordination of U.S. regional observing activities. A common theme is the need for more sustained time series of critical physical and biological variables that document change, especially in nearshore, coastal, and benthic habitats. Additionally, there is a need to development and maintain bridges to transfer new research knowledge, understanding, and analysis tools to the state, provincial, and federal agencies and fisheries management councils where EAM will be implemented.

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