scholarly journals Food web and ecological models used to assess aquatic ecosystems submitted to aquaculture activities

2019 ◽  
Vol 49 (2) ◽  
Author(s):  
Rodrigo Sávio Teixeira de Moura ◽  
Gustavo Gonzaga Henry-Silva
Keyword(s):  
Mathematical Modelling ◽  
Aquatic Ecosystems ◽  
Environmental Changes ◽  
Production Systems ◽  
Relevant Information ◽  
Ecological Modelling ◽  
Aquatic Environments ◽  
Aquatic Communities ◽  
Nutrient Mass Balance ◽  
Changes Over Time

ABSTRACT: Continental aquatic ecosystems play a fundamental role in economic and social development; however, they are vulnerable to environmental degradation due to the various stresses to which they are submitted. Aquaculture is among the main anthropic activities that influence these environments. Mathematical modelling of aquatic ecosystems performed using a set of computational tools allows simplified representation of environment regarding its biotic and abiotic components. Some of the most used techniques are: hydrodynamic modelling, focusing on the dispersion of nutrients; nutrient-mass balance modelling, especially phosphorus; bioenergetic modelling in animal production systems, with an estimate of the generation of residues in the environment by farmed animals; and trophic and ecological modelling, focusing on aquatic communities and their interactions. These techniques help understand changes caused by aquaculture systems in aquatic environments. In this way, it is possible to estimate the magnitude and extent of the impacts of these activities by simulating the possible environmental changes over time. It can be concluded that techniques involving mathematical modelling can provide relevant information for future impacts prediction on aquatic environments, promoting the management of water resources and their multiple uses.

scholarly journals First report on phytoplankton communities of Barishal City, Bangladesh

2020 ◽  
pp. 142-147
Author(s):  
Shaswati Chakraborty ◽  
Dipalok Karmaker ◽  
Subroto Kumar Das ◽  
Riyad Hossen
Keyword(s):  
Aquatic Ecosystems ◽  
Species Number ◽  
Aquatic Environments ◽  
Primary Producers ◽  
First Report ◽  
Biodiversity Indices ◽  
Phytoplankton Communities ◽  
Living Organisms ◽  
The City ◽  
Total Species

Phytoplanktons, also called microalgae, are microscopic photosynthetic living organisms that generally found in aquatic environments. Although they are considered as the most important primary producers and bioindicators of aquatic ecosystems, there was no previous report found for Barishal City about these tiny organisms. Consequently, the present study selected 10 freshwater reservoirs from the city to investigate phytoplankton communities and listed 110 taxa under 4 phyla, 7 classes, 18 orders, 24 families and 49 genera. The distribution of Chlorophytes was abundant relatively in terms of species number (45 taxa) followed by Euglenophytes, Chlorophytes and Cyanophytes in this area. Only Euglenaceae possessed one-third of the total species of this report. Among all stations, the highest number of taxa was recorded from station 2 and according to nine biodiversity indices, the station 2 and 9 showed comparatively good results. All of the recorded taxa were previously mentioned by different authors from Bangladesh.

scholarly journals New kid on the block: Research of alpine-lake macroinvertebrates in the Tatra Mountains enhanced by DNA barcoding and metabarcoding

2021 ◽  
Vol 4 ◽  
Author(s):  
Ondrej Vargovčík ◽  
Zuzana Čiamporová-Zaťovičová ◽  
Fedor Čiampor Jr
Keyword(s):  
Large Scale ◽  
Environmental Changes ◽  
Human Impacts ◽  
Sampling Error ◽  
Alpine Lakes ◽  
Alpine Lake ◽  
Tatra Mountains ◽  
Aquatic Communities ◽  
Wide Range ◽  
The Tatra Mountains

State of ecosystems and biodiversity protection are becoming the key interests for modern society due to climate change and negative human impacts (Leese 2018). Environmental changes in freshwaters are indicated also by benthic communities, especially in sensitive ecosystems like alpine lakes (Fjellheim 2009). Moreover, remoteness and isolation of alpine lakes make them a source of biodiversity, which is worth conserving (Hamerlík 2014). A promising tool for efficient large-scale monitoring of aquatic communities is DNA metabarcoding (Leese 2018). In this study, we applied metabarcoding to analyse macrozoobenthos of 12 lakes in the Tatra Mountains, using benthic bulk samples and eDNA filtered from water (Fig. 1). In compliance with recent publications, eDNA amplified with BF3/BR2 primers resulted in high percentage of non-invertebrate reads (Leese 2021). Based on in silico tests with the obtained sequences, we confirm that the recently developed EPTDr2n primer enables minimizing non-target amplification even with eDNA filtered from alpine-lake water (Elbrecht and Leese 2017). This ability is facilitated by 3’ end of the primer and we observed the two important mismatches in non-target sequences from our study (Leese 2021). Thus, our future analyses of eDNA (and bulk-sample fixative) will benefit from the new primer. Concerning bulk samples, a wide range of invertebrate taxa was assigned to the OTUs and they showed good congruence with previous studies using morphological determination (e.g. Krno 2006). Certain differences with (and among) the previous records per lake were observed, which could suggest ecological changes, but at the moment the influence of sampling error cannot be excluded. In eDNA, several taxa were congruent with the previous records, but their amount and read abundance was considerably lower due to non-target amplification. Apart from that, filling gaps in barcoding databases remains one of our priorities, as identification to species or genus level was not yet possible for some invertebrate OTUs. In addition, we subjected the NGS data to denoising and abundance-filtering in order to explore haplotype-level diversity (Andújar 2021). Although more comprehensive conclusions will be possible only after obtaining data from more lakes and years, already the two metabarcoding experiments presented here enabled us to efficiently detect within-species genetic diversity and identify a large variety of taxa, including groups that would otherwise be omitted or very challenging to identify. This underlines the potential of DNA methods to provide valuable ecological and biodiversity data across the tree of life for modern biomonitoring. This study was realized with support from VEGA 2/0030/17 and VEGA 2/0084/21.

Construction of an Indicator System for Integrated Assessment of Environmental Quality of the Dianchi Basin

2011 ◽  
Vol 356-360 ◽  
pp. 903-907
Author(s):  
Ai Jun Li ◽  
Yan Ying Guo ◽  
Feng He ◽  
Rui Jia Yuan
Keyword(s):  
Environmental Quality ◽  
Integrated Assessment ◽  
Large Scale ◽  
Environmental Changes ◽  
Indicator System ◽  
Regional Environment ◽  
Definition Of ◽  
Changes Over Time ◽  
Regional Environmental Quality

There are few indicator systems available for monitoring and assessing the environmental quality of large-scale regions. We constructed an indicator system for integrated assessment of the environmental quality of the Dianchi Basin. First, the definition of regional environmental quality is determined by both the supply of materials and energy in the region and the extent to which the region is polluted. Second, the indicator categories used for assessment mainly comprise vegetation biomass and the concentrations of various pollutants. Third, owing to spatial heterogeneity of a region, evaluation of the regional environment first requires division into sub-regions, each of which should be relatively homogeneous with regard to physical conditions (e.g. marine and terrestrial) and appearance (e.g. vegetation cover). Finally, the mathematical models for assessing regional environmental quality can be built according to the relationships between the various indicators, the sub-regions and regional environmental quality. The indicator system built using this approach can reflect environmental changes over time and identifies reasons for environmental variation.

Interspecific Interactions II: Competition and Mutualism

2020 ◽  
pp. 67-84
Author(s):  
Michael J. Fogarty ◽  
Jeremy S. Collie
Keyword(s):  
Resource Use ◽  
Population Change ◽  
Interspecific Interactions ◽  
Competitive Interactions ◽  
Aquatic Environments ◽  
Biotic Interaction ◽  
Controlled Experiments ◽  
Aquatic Communities ◽  
Shared Resource ◽  
Differential Reduction

Competition and mutualism are important forms of biotic interaction in aquatic communities. Quantification of the population and community-level effects of these interactions has historically been less common in fisheries analyses than predation. In part, this reflects the difficulties in conducting controlled experiments for larger-bodied organisms in aquatic environments. Documenting competition entails not only identifying patterns of shared resource use but evidence that these resources are limiting. Inferences concerning competitive interactions in non-experimental settings may be possible if histories of population change for putative competitors are available and quantifiable interventions involving the addition of a species (through deliberate or inadvertent introductions) or a differential reduction in abundance of the species through harvesting is undertaken. Care must be taken to account for other changes in the environment in these uncontrolled quasi-experiments. Mutualistic interactions are widely recognized in aquatic ecosystems but far less commonly quantified than competition.

Proximity to wastewater effluent alters behaviour in bluegill sunfish (Lepomis machrochirus)

Behaviour ◽  
2019 ◽  
Vol 156 (15) ◽  
pp. 1495-1517 ◽  
Author(s):  
Adrienne R. McLean ◽  
Sherry N.N. Du ◽  
Jasmine A. Choi ◽  
Brett M. Culbert ◽  
Erin S. McCallum ◽  
...  
Keyword(s):  
Predator Avoidance ◽  
Reference Site ◽  
Lepomis Macrochirus ◽  
Treatment Plant ◽  
Wastewater Effluent ◽  
Aquatic Environments ◽  
Bluegill Sunfish ◽  
Aquatic Communities ◽  
Risk Of Predation ◽  
Negative Impacts

Abstract Wastewater from municipal, agricultural and industrial sources is a pervasive contaminant of aquatic environments worldwide. Most studies that have investigated the negative impacts of wastewater on organisms have taken place in a laboratory. Here, we tested whether fish behaviour is altered by exposure to environmentally relevant concentrations of wastewater effluent in the field. We caged bluegill sunfish (Lepomis macrochirus) for 28 days at two sites downstream (adjacent to and 870 m) from a wastewater treatment plant and at a reference site without wastewater inputs. We found that exposed fish had a dampened response to simulated predation compared to unexposed fish, suggesting that fish may be at greater risk of predation after exposure to wastewater effluent. Fish held at the different sites did not differ in activity and exploration. Our results suggest that predator avoidance may be impaired in fish exposed to wastewater effluent, which could have detrimental implications for aquatic communities.

Mathematical-Modelling Simulation Applied to Help in the Decision-Making Process on Environmental Impact Assessment of Agriculture

2011 ◽  
pp. 199-233
Author(s):  
Maria Pessoa ◽  
Elizabeth Fernandes ◽  
Sonia Nascimento de Queiroz ◽  
Vera Ferracini ◽  
Marco Gomes ◽  
...  
Keyword(s):  
Decision Making ◽  
Environmental Impact ◽  
Mathematical Modelling ◽  
Impact Assessment ◽  
Environmental Impact Assessment ◽  
Production Systems ◽  
Decision Making Process ◽  
Aquifer Recharge ◽  
Guarani Aquifer

The present chapter provides a brief explanation on some aspects involved in the development of models and mathematical-modelling simulations, to show their benefits to the decision-making process in the environmental impact assessment of agriculture. Aspects concerning the agroecosystems were also presented toward the sustainability of Brazilian agricultural production systems. Some applications which have been developed in Brazil were pointed out, as well as a specific case study conducted at the Guarani aquifer recharge area located in Ribeirão Preto, São Paulo state, in order to show the influence of input data on the results provided by CMLS94 simulator.

Hydrological change and human activity during Yuan–Ming Dynasties in the Loulan area, northwestern China

The Holocene ◽  
2018 ◽  
Vol 28 (8) ◽  
pp. 1266-1275 ◽  
Author(s):  
Kangkang Li ◽  
Xiaoguang Qin ◽  
Lei Zhang ◽  
Zhaoyan Gu ◽  
Bing Xu ◽  
...  
Keyword(s):  
Human Activity ◽  
Little Ice Age ◽  
Environmental Changes ◽  
Ice Age ◽  
Flood Events ◽  
Lop Nur ◽  
Plant Remains ◽  
Ancient Silk Road ◽  
Climate Transition ◽  
Changes Over Time

Human activity on arid lands has been related to oases evolution. The ancient Loulan, an important transportation hub of the ancient Silk Road, developed on an ancient oasis on the west bank of the lake Lop Nur in Xinjiang, China. Previous studies and historical documents suggest that the region has experienced dramatic natural environmental and human activity–related changes over time, transitioning from a particularly prosperous oasis to a depopulated zone with harsh environment after about 1500 a BP (before present, where present = AD 1950). Based on systematic radiocarbon (14C) dating for natural plant remains and archeological sites in the Loulan area, it was revealed that the region re-experienced oasis environment from 1260 to 1450 cal. AD, corresponding to the Yuan–Ming Dynasties, which is the climate transition stage from the ‘Medieval Warm Period’ to the ‘Little Ice Age’, encompassing a series of pulse-like flood events which cannot be identified from lacustrine deposition due to the limits of sampling resolution and dating. It was found that humans re-occupied the Loulan area and built canals to irrigate farmlands during the period. The more habitable hydrological conditions that resulted from these environmental changes present one major reason for the re-emergence of human activities in the Loulan area.

scholarly journals The need to account for cell biology in characterizing predatory mixotrophs in aquatic environments

2019 ◽  
Vol 374 (1786) ◽  
pp. 20190090 ◽  
Author(s):  
Susanne Wilken ◽  
Charmaine C. M. Yung ◽  
Maria Hamilton ◽  
Kenneth Hoadley ◽  
Juliana Nzongo ◽  
...  
Keyword(s):  
Organic Matter ◽  
Single Cell ◽  
Gold Standard ◽  
Cell Biology ◽  
Aquatic Ecosystems ◽  
Eukaryotic Cells ◽  
Food Chains ◽  
Aquatic Environments ◽  
Unicellular Eukaryotes ◽  
Aquatic Food

Photosynthesis in eukaryotes first arose through phagocytotic processes wherein an engulfed cyanobacterium was not digested, but instead became a permanent organelle. Other photosynthetic lineages then arose when eukaryotic cells engulfed other already photosynthetic eukaryotic cells. Some of the resulting lineages subsequently lost their ability for phagocytosis, while many others maintained the ability to do both processes. These mixotrophic taxa have more complicated ecological roles, in that they are both primary producers and consumers that can shift more towards producing the organic matter that forms the base of aquatic food chains, or towards respiring and releasing CO 2 . We still have much to learn about which taxa are predatory mixotrophs as well as about the physiological consequences of this lifestyle, in part, because much of the diversity of unicellular eukaryotes in aquatic ecosystems remains uncultured. Here, we discuss existing methods for studying predatory mixotrophs, their individual biases, and how single-cell approaches can enhance knowledge of these important taxa. The question remains what the gold standard should be for assigning a mixotrophic status to ill-characterized or uncultured taxa—a status that dictates how organisms are incorporated into carbon cycle models and how their ecosystem roles may shift in future lakes and oceans. This article is part of a discussion meeting issue ‘Single cell ecology’.

Wise use: using ecological models to understand and manage aquatic ecosystems

2020 ◽  
Vol 71 (1) ◽  
pp. 46 ◽  
Author(s):  
Rebecca E. Lester
Keyword(s):  
Aquatic Ecosystems ◽  
Ecological Models ◽  
Ecological Modelling ◽  
Ecological Data ◽  
Critical Question ◽  
Sensitivity Testing ◽  
Response Models ◽  
Ecological Response ◽  
Recommendations For Action ◽  
Ongoing Development

Using ecological-response models to understand and improve management of aquatic ecosystems is increasingly common. However, there are many questions about reliability and utility that can make the use of ecological modelling fraught. One critical question is how ecological-response models translate to what happens in practice. Many models purport to improve management by simulating ecological response to changing conditions. This suggests that tangible benefits (e.g. increased biodiversity) should flow when recommendations for action are implemented. But testing these links is rare and there are implications if those links are tenuous. One problem leading to a lack of congruence between models and reality can be a lack of ecological data for the system being modelled. Incomplete understanding, erroneous assumptions about drivers or degree of variability, and uncritical use of expert opinion can all result in models that may be more likely to mislead than inform. Explicit validation of models, sensitivity testing and ongoing development of novel solutions to deal with incomplete data can all assist. So, wise and critical use of ecological models provides one mechanism to increase our ability to quantify adverse effects on, and project future trajectories of, aquatic ecosystems.

scholarly journals A Suppression Method of Concentration Background Noise by Transductive Transfer Learning for a Metal Oxide Semiconductor-Based Electronic Nose

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1913
Author(s):  
Huixiang Liu ◽  
Qing Li ◽  
Zhiyong Li ◽  
Yu Gu
Keyword(s):  
Transfer Learning ◽  
Environmental Changes ◽  
Oxide Semiconductor ◽  
Target Domain ◽  
Fisher Linear Discriminant ◽  
Linear Discriminant ◽  
Signal Features ◽  
Changes Over Time ◽  
Independence Criterion ◽  
Better Than

Signal drift caused by sensors or environmental changes, which can be regarded as data distribution changes over time, is related to transductive transfer learning, and the data in the target domain is not labeled. We propose a method that learns a subspace with maximum independence of the concentration features (MICF) according to the Hilbert-Schmidt Independence Criterion (HSIC), which reduces the inter-concentration discrepancy of distributions. Then, we use Iterative Fisher Linear Discriminant (IFLD) to extract the signal features by reducing the divergence within classes and increasing the divergence among classes, which helps to prevent inconsistent ratios of different types of samples among the domains. The effectiveness of MICF and IFLD was verified by three sets of experiments using sensors in real world conditions, along with experiments conducted in the authors’ laboratory. The proposed method achieved an accuracy of 76.17%, which was better than any of the existing methods that publish their data on a publicly available dataset (the Gas Sensor Drift Dataset). It was found that the MICF-IFLD was simple and effective, reduced interferences, and deftly managed tasks of transfer classification.

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