Microplastics in lakes and rivers: an issue of emerging significance to limnology

2021 ◽  
Author(s):  
Genevieve D’Avignon ◽  
Irene Gregory-Eaves ◽  
Anthony Ricciardi
Keyword(s):  
Field Survey ◽  
Size Range ◽  
Fish Larvae ◽  
Toxic Substances ◽  
Environmental Persistence ◽  
Ecological Processes ◽  
Water Columns ◽  
Spatio Temporal ◽  
Living Organisms ◽  
Contaminated Marine Sediments

Microplastics—plastic particles in the size range of planktonic organisms—have been found in the water columns and sediments of lakes and rivers globally. The number and mass of plastic particles drifting through a river can exceed those of living organisms such as zooplankton and fish larvae. In freshwater sediments, concentrations of microplastics reach the same magnitude as in the world’s most contaminated marine sediments. Such particles are derived from a unique biogeochemical cycle that ultimately influences productivity, biodiversity, and ecosystem functioning. Furthermore, microplastics act as vectors of toxic substances to invertebrates, fishes, herpetofauna, and waterfowl. We contend that the concentration of this distinct particle component is an ecologically significant parameter of inland waterbodies because of its ubiquity, environmental persistence, and interactions with key ecological processes. No environmental field survey that has searched for microplastics has yet failed to detect their presence. Standardized limnological protocols are needed to compare spatio-temporal variation in the concentration of microplastics within and across watersheds. Data obtained from such protocols would facilitate environmental monitoring and inform policy for managing plastic waste; furthermore, they would enable more accurate modeling of contaminant cycling and the development of a global plastic budget that identifies sources, distribution and circulation pathways, reservoir size and retention times.

Short-term growth (RNA/DNA ratio) of yellow perch (Perca flavescens) in relation to environmental influences and spatio-temporal variation in a shallow fluvial lake

2007 ◽  
Vol 64 (12) ◽  
pp. 1646-1655 ◽  
Author(s):  
Hélène Glémet ◽  
Marco A Rodríguez
Keyword(s):  
Temporal Variation ◽  
Water Level ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Negative Influence ◽  
Water Levels ◽  
Short Term ◽  
Ecological Processes ◽  
Flood Pulse Concept ◽  
Spatio Temporal

Shallow fluvial lakes are heterogeneous ecosystems in which marked spatio-temporal variation renders difficult the analysis of key ecological processes, such as growth. In this study, we used generalized additive modelling of the RNA/DNA ratio, an index of short-term growth, to investigate the influence of environmental variables and spatio-temporal variation on growth of yellow perch (Perca flavescens) in Lake St. Pierre, Quebec, Canada. Temperature and water level had seemingly stronger effects on short-term growth than seasonal change or spatial variation between and along the lakeshores. Consistent with previous studies, the maximum RNA/DNA ratio was found at 20.5 °C, suggesting that our approach provides a useful tool for estimating thermal optima for growth in the field. The RNA/DNA ratio showed a positive relationship with water level, as predicted by the flood pulse concept, a finding with implications for ecosystem productivity in fluvial lakes. The RNA/DNA ratio was more variable along the north than the south shore, possibly reflecting exposure to more differentiated water masses. The negative influence of both high temperatures and low water levels on growth points to potential impacts of climatic change on fish production in shallow fluvial lakes.

Geo-Informatics for Land Use and Biodiversity Studies

2011 ◽  
pp. 52-77
Author(s):  
P. K. Joshi ◽  
Neena Priyanka
Keyword(s):  
Land Use ◽  
Temporal Dynamics ◽  
Mitigation Measures ◽  
Conservation Strategies ◽  
Ecological Processes ◽  
Holistic Understanding ◽  
Global Positioning ◽  
Geospatial Tools ◽  
Spatio Temporal ◽  
Impact On Biodiversity

The dynamics of land use/land cover (LU/LC) is a manifestation of the cyclic correlation among the kind and magnitude of causes, impacts, responses and resulting ecological processes of the ecosystem. Thus, the holistic understanding of the complex mechanisms that control LU/LC requires synergetic adoption of measurement approaches, addressing issues, and identifying drivers of change and state of art technologies for mitigation measures. As the spatio-temporal heterogeneity of the LU/LC increases, its impact on biodiversity becomes even more difficult to anticipate. Thus, in order to understand the spatio-temporal dynamics of change in landscape and its relationship to biodiversity, it is necessary to reliably identify and quantify the indicators of change. In addition, it is also important to have better understanding of the technologies and techniques that serve as complimentary tool for land mitigation and conservation planning. Against this background, the chapter aims to synthesize LU/LC studies worldwide and their impacts on biodiversity. This chapter explores identification and analysis of key natural, socio-economic and regulatory drivers for LU/LC. Finally, it attempts to collate some LU/LC studies involving usage of geospatial tools, such as satellite remote sensing, Geographic Information System (GIS), Global Positioning System (GPS), and integrative tools, besides conventional approaches that could assist decision makers, land managers, stakeholders and researchers in better management and formulation of conservation strategies based on scientific grounds.

scholarly journals Polyacrylamide Bead Sensors for in vivo Quantification of Cell-Scale Stress in Zebrafish Development

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
N. Träber ◽  
K. Uhlmann ◽  
S. Girardo ◽  
G. Kesavan ◽  
K. Wagner ◽  
...  
Keyword(s):  
Computational Analysis ◽  
Tissue Level ◽  
Quantitative Investigation ◽  
Pulsatile Pressure ◽  
Spatio Temporal ◽  
Stress Sensing ◽  
Living Organisms ◽  
Insight Into

AbstractMechanical stress exerted and experienced by cells during tissue morphogenesis and organ formation plays an important role in embryonic development. While techniques to quantify mechanical stresses in vitro are available, few methods exist for studying stresses in living organisms. Here, we describe and characterize cell-like polyacrylamide (PAAm) bead sensors with well-defined elastic properties and size for in vivo quantification of cell-scale stresses. The beads were injected into developing zebrafish embryos and their deformations were computationally analyzed to delineate spatio-temporal local acting stresses. With this computational analysis-based cell-scale stress sensing (COMPAX) we are able to detect pulsatile pressure propagation in the developing neural rod potentially originating from polarized midline cell divisions and continuous tissue flow. COMPAX is expected to provide novel spatio-temporal insight into developmental processes at the local tissue level and to facilitate quantitative investigation and a better understanding of morphogenetic processes.

scholarly journals Generating High Spatio-Temporal Resolution Fractional Vegetation Cover by Fusing GF-1 WFV and MODIS Data

2019 ◽  
Vol 11 (19) ◽  
pp. 2324 ◽  
Author(s):  
Tao ◽  
Jia ◽  
Zhao ◽  
Wei ◽  
Xie ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Vegetation Cover ◽  
Field Survey ◽  
Lower Probability ◽  
Important Indicator ◽  
The Real ◽  
Modis Data ◽  
Fractional Vegetation Cover ◽  
Spatio Temporal ◽  
Reflectance Data

As an important indicator to characterize the surface vegetation, fractional vegetation cover (FVC) with high spatio-temporal resolution is essential for earth surface process simulation. However, due to technical limitations and the influence of weather, it is difficult to generate temporally continuous FVC with high spatio-temporal resolution based on a single remote-sensing data source. Therefore, the objective of this study is to explore the feasibility of generating high spatio-temporal resolution FVC based on the fusion of GaoFen-1 Wide Field View (GF-1 WFV) data and Moderate-resolution Imaging Spectroradiometer (MODIS) data. Two fusion strategies were employed to identify a suitable fusion method: (i) fusing reflectance data from GF-1 WFV and MODIS firstly and then estimating FVC from the reflectance fusion result (strategy FC, Fusion_then_FVC). (ii) fusing the FVC estimated from GF-1 WFV and MODIS reflectance data directly (strategy CF, FVC_then_Fusion). The FVC generated using strategies FC and CF were evaluated based on FVC estimated from the real GF-1 WFV data and the field survey FVC, respectively. The results indicated that strategy CF achieved higher accuracies with less computational cost than those of strategy FC both in the comparisons with FVC estimated from the real GF-1 WFV (CF:R2 = 0.9580, RMSE = 0.0576; FC: R2 = 0.9345, RMSE = 0.0719) and the field survey FVC data (CF: R2 = 0.8138, RMSE = 0.0985; FC: R2 = 0.7173, RMSE = 0.1214). Strategy CF preserved spatial details more accurately than strategy FC and had a lower probability of generating abnormal values. It could be concluded that fusing GF-1 WFV and MODIS data for generating high spatio-temporal resolution FVC with good quality was feasible, and strategy CF was more suitable for generating FVC given its advantages in estimation accuracy and computational efficiency.

scholarly journals Inventory of Spatio-Temporal Methane Emissions from Livestock and Poultry Farming in Beijing

2019 ◽  
Vol 11 (14) ◽  
pp. 3858
Author(s):  
Yixuan Guo ◽  
Yidong Wang ◽  
Shufeng Chen ◽  
Shunan Zheng ◽  
Changcheng Guo ◽  
...  
Keyword(s):  
Field Survey ◽  
Tier 2 ◽  
Ch4 Emission ◽  
Intergovernmental Panel ◽  
Enteric Fermentation ◽  
Ch4 Emissions ◽  
Spatio Temporal ◽  
Poultry Farming ◽  
Feeding Systems

Livestock and poultry farming sectors are among the largest anthropogenic methane (CH4) emission sources, mainly from enteric fermentation and manure management. Previous inventories of CH4 emission were generally based on constant emission factor (EF) per head, which had some weaknesses mainly due to the succession of breeding and feeding systems over decades. Here, more reliable long-term changes of CH4 emissions from livestock and poultry farming in Beijing are estimated using the dynamic EFs based on the Intergovernmental Panel on Climate Change (IPCC) Tier 2 method, and high-resolution spatial patterns of CH4 emissions are also estimated with intensive field survey. The results showed that the estimated CH4 emissions derived by dynamic EFs were approximately 13–19% lower than those based on the constant EF before 2010. After 2011, however, the dynamic EFs-derived CH4 emissions were a little higher (3%) than the constant EF method. Temporal CH4 emissions in Beijing had experienced four developing stages (1978–1988: stable; 1989–1998: slow growth; 1999–2004: rapid growth and reached hot moments; 2005–2014: decline) during 1978–2014. Over the first two decades, the contributions of pigs (45%) and cattle (46%) to annual CH4 emission were similar; subsequently, the cattle emitted more CH4 compared to the pigs. At a spatial scale, Shunyi, Daxing, and Tongzhou districts with more cattle and pigs are the hotspots of CH4 emission. In conclusion, the dynamic EFs method obviously improved the spatio-temporal estimates of CH4 emissions compared to the constant EF approach, and the improvements depended on the period and aquaculture structure. Therefore, the dynamic EFs method should be recommended for estimating CH4 emissions from livestock and poultry farming in the future.

scholarly journals Geospatial Assessment of Forest Fragmentation and its Implications for Ecological Processes in Tropical Forests

2017 ◽  
Vol 10 (2) ◽  
pp. 19-34 ◽  
Author(s):  
Kayode Adewale Adepoju ◽  
Ayobami T. Salami
Keyword(s):  
Forest Fragmentation ◽  
Negative Impact ◽  
Landscape Connectivity ◽  
Landscape Patterns ◽  
Forest Environment ◽  
Ecological Processes ◽  
Biodiversity Indicators ◽  
Southwestern Nigeria ◽  
Spatio Temporal ◽  
Landscape Variability

Abstract The study assessed the patterns of spatio-temporal configuration imposed on a forest landscape in Southwestern Nigeria due to fragmentation for the period 1986 – 2010 in order to understand the relationship between landscape patterns and the ecological processes influencing the distribution of species in tropical forest environment. Time-series Landsat TM and ETM satellite images and forest inventory data were pre-processed and classified into four landuse/landcover categories using maximum likelihood classification algorithm. Fragstats software was used for the computation of seven landscape and six class level metrics to provide indicators of fragmentation and landscape connectivity from the classified images. The result shows that although deforestation reduced between 2000 and 2010, fragmentation, however intensified during the 24 years period. Fragmentation was highest between 1991 and 2000, leading to significant landscape variability, alteration in the general biotic and abiotic conditions and exchange of material and energy. While it appears that overall forest area increased between 2000 and 2010, connectivity and biodiversity indicators declined the most during this period. The resulting scenario is that forest fragmentation, despite the control of deforestation in the last decade of this study have certainly not receded in the study area. This may continue to have subtle negative impact on exchange of material and energy in the ecosystem, contribute to increased depletion of vital forest resources and the disappearance of wildlife from previously known areas.

scholarly journals Modelling the mobility of living organisms in heterogeneous landscapes: does memory improve foraging success?

2010 ◽  
Vol 368 (1933) ◽  
pp. 5645-5659 ◽  
Author(s):  
Denis Boyer ◽  
Peter D. Walsh
Keyword(s):  
Foraging Efficiency ◽  
Mobility Patterns ◽  
Heterogeneous Landscapes ◽  
Technological Advances ◽  
Spatio Temporal ◽  
Living Organisms ◽  
Large Animals ◽  
Micro Organisms ◽  
Random Nature ◽  
Basic Movement

Thanks to recent technological advances, it is now possible to track with an unprecedented precision and for long periods of time the movement patterns of many living organisms in their habitat. The increasing amount of data available on single trajectories offers the possibility of understanding how animals move and of testing basic movement models. Random walks have long represented the main description for micro-organisms and have also been useful to understand the foraging behaviour of large animals. Nevertheless, most vertebrates, in particular humans and other primates, rely on sophisticated cognitive tools such as spatial maps, episodic memory and travel cost discounting. These properties call for other modelling approaches of mobility patterns. We propose a foraging framework where a learning mobile agent uses a combination of memory-based and random steps. We investigate how advantageous it is to use memory for exploiting resources in heterogeneous and changing environments. An adequate balance of determinism and random exploration is found to maximize the foraging efficiency and to generate trajectories with an intricate spatio-temporal order, where travel routes emerge without multi-step planning. Based on this approach, we propose some tools for analysing the non-random nature of mobility patterns in general.

scholarly journals Does Shoot Apical Meristem Function as the Germline in Safeguarding Against Excess of Mutations?

2021 ◽  
Vol 12 ◽  
Author(s):  
Agata Burian
Keyword(s):  
Cell Fate ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Cell Lineage ◽  
Temporal Distribution ◽  
Tissue Level ◽  
Protective Mechanisms ◽  
Genetic Continuity ◽  
Spatio Temporal ◽  
Living Organisms

A genetic continuity of living organisms relies on the germline which is a specialized cell lineage producing gametes. Essential in the germline functioning is the protection of genetic information that is subjected to spontaneous mutations. Due to indeterminate growth, late specification of the germline, and unique longevity, plants are expected to accumulate somatic mutations during their lifetime that leads to decrease in individual and population fitness. However, protective mechanisms, similar to those in animals, exist in plant shoot apical meristem (SAM) allowing plants to reduce the accumulation and transmission of mutations. This review describes cellular- and tissue-level mechanisms related to spatio-temporal distribution of cell divisions, organization of stem cell lineages, and cell fate specification to argue that the SAM functions analogous to animal germline.

scholarly journals Heavy Metals in Agricultural Soils

2003 ◽  
pp. 85-89
Author(s):  
Kamilla Taraczközi
Keyword(s):  
Heavy Metals ◽  
Soil Pollution ◽  
Agricultural Soils ◽  
Great Part ◽  
Soil Conditions ◽  
Soil Productivity ◽  
Toxic Substances ◽  
High Concentration ◽  
Small Areas ◽  
Living Organisms

The soil constitutes the basis of the food chain. To keep soil conditions in a good trim is very important, it’s part of the sustainable development and of producing food supply harmless to health.In some cases, soil productivity is the only important part, qualitative requirements or economical characteristics can improve it. The soil is threatened by two danger factors: the soil degradation and the soil pollution. The accumulation of different harmful and/or toxic substances in the soil is well known. Heavy metals constitute a part of it. Metals in the soil and in the soil-solution are balanced. This balance depends on the type of the metal, on the pH, on the cation-band capacity of the soil, on the redox relations and the concentration of cations in the soil.To be able to handle the metal contamination of the soil, it is important to estimate the form, the possible extension and the concentration of metals.Of course, the different types of soils have different physical-chemical, biological and buffer capacity, they can moderate or reinforce the harmful effects of heavy metals. To draw general conclusion of the dispersion and quantitative relations on the metals originated from different contamination sources is hard, because in some emissive sources contamination is limited in small areas but on a high level, some others usually expand on larger areas, and as a result of equal dispersion, the contamination’s level is lower.Heavy metals – unlike alkali ions – strongly bond to organic materials, or infiltrate in a kelát form. Their outstanding characteristic is the tendency to create metal-complex forms. Kelats take part in the uptaking and transportation of heavy metals. Heavy metals exert their effects mostly as enzyme-activators.The metals cannot degrade in an organic way, they accumulate in living organisms, and they can form toxic compounds through biochemical reactions.Lot of the heavy metals accumulate on the boundaries of the abiotic systems (air/soil, water/sediment), when physical or chemical parameters change, and this influences their remobilization.Human activity plays a great part in heavy metal mobilization, results in the human origin of most biochemical process of metals.To understand the toxic influence of accumulated metals of high concentration, their transportation from soils to plants or their damage in human health, must clearly defined and investigated.For effective protection against soil pollution, the types and levels of harmful pollution to soil must identified, regarding legal, technical and soil-science aspects, preferable in a single way. Difficulties in this area mean that toxicity depends on loading, uptake, soil characteristics and living organisms (species, age, condition etc.), furthermore, local and economic conditions considerably differ.

scholarly journals Evaluation of changes in ecological conditions of wetlands in the Teniz-Korgalzhin depression (Kazakhstan)

2019 ◽  
Vol 9 (4) ◽  
pp. 719-722
Author(s):  
Y. N. Sagatbayev ◽  
O. N. Baryshnikova ◽  
Y. P. Krupochkin ◽  
O. B. Mazbayev
Keyword(s):  
Remote Sensing ◽  
Remote Sensing Data ◽  
Space Images ◽  
Earth Remote Sensing ◽  
Ecological Conditions ◽  
Spatial Differences ◽  
Depression Wetlands ◽  
Spatio Temporal ◽  
Using Data ◽  
Living Organisms

The article presents the results of a study of the long-term dynamics of the state of ecosystems of the Teniz-Korgalzhyn depression, carried out using data from the Earth remote sensing (ERS). Based on the analysis of space images, the formation factors of modern environmental conditions are established. In the study area, such factors are positional and barrier factors, as well as the confinement of individual surface sections to different-height layers of the Earth's surface. An analysis of the Landsat series of space images taken at different time, made it possible to establish spatial differences in the intensity of phytomass accumulation in areas located in different landscape locations. The spatio-temporal variability of the ecological conditions of the Teniz-Korgalzhin depression wetlands is accompanied by a change in the amount of food supply and the number of living organisms. Monitoring of these changes on the basis of Earth remote sensing data will allow to prove measures to preserve the biodiversity of the Teniz-Korgalzhin depression wetlands timely.

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