scholarly journals Distribution of Toxic Cyanobacteria in Volcanic Lakes of the Azores Islands

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3385
Author(s):  
Rita Cordeiro ◽  
Rúben Luz ◽  
Joana Vilaverde ◽  
Vitor Vasconcelos ◽  
Amélia Fonseca ◽  
...  
Keyword(s):  
Global Climate ◽  
Control Measures ◽  
Anthropogenic Pressures ◽  
Explanatory Variables ◽  
Cyanobacteria Blooms ◽  
Bloom Formation ◽  
Toxic Cyanobacteria ◽  
Volcanic Lakes ◽  
Toxicity Risk

Eutrophication and global climate change gather advantageous conditions for cyanobacteria proliferation leading to bloom formation and cyanotoxin production. In the Azores, eutrophication is a major concern, mainly in lakes where fertilizers and organic matter discharges have increased nutrient concentration. In this study, we focused on understanding the influence of environmental factors and lake characteristics on (i) cyanobacteria diversity and biomass and (ii) the presence of toxic strains and microcystin, saxitoxin, anatoxin-a, and cylindrospermopsin cyanotoxin-producing genes. Fifteen lakes from the Azores Archipelago were sampled seasonally, environmental variables were recorded in situ, cyanobacteria were analyzed with microscopic techniques, and cyanotoxin-producing genes were targeted through conventional PCR. Statistical analysis (DistLM) showed that lake typology-associated variables (lake’s depth, area, and altitude) were the most explanatory variables of cyanobacteria biomass and cyanotoxin-producing genes presence, although trophic variables (chlorophyll a and total phosphorus) influence species distribution in each lake type. Our main results revealed higher cyanobacteria biomass/diversity, and higher toxicity risk in lakes located at lower altitudes, associated with deep anthropogenic pressures and eutrophication scenarios. These results emphasize the need for cyanobacteria blooms control measures, mainly by decreasing anthropogenic pressures surrounding these lakes, thus decreasing eutrophication. We also highlight the potential for microcystin, saxitoxin, and anatoxin-a production in these lakes, hence the necessity to implement continuous mitigation protocols to avoid environmental and public health toxicity events.

scholarly journals Toxic cyanobacteria and widlife conservation: Proposal of a procedure to demonstrate waterbird mass mortalities by microcystin.

2009 ◽  
Vol 34 ◽  
pp. 5-10 ◽  
Author(s):  
Maria Aránzazu Mateos-Sanz ◽  
Daniel Carrera ◽  
Victoria López-Rodas ◽  
Eduardo Costas
Keyword(s):  
National Park ◽  
Cyclic Peptides ◽  
Wildlife Conservation ◽  
Post Mortem ◽  
Doñana National Park ◽  
Cyanobacteria Blooms ◽  
Toxic Cyanobacteria ◽  
El Sistema ◽  
Mass Mortalities

ABSTRACT. Toxic cyanobacteria and wildlife conservation: proposal of a procedure to demonstrate waterbird mass mortalities by microcystin. The role of toxic cyanobacteria in wildlife conservation is poorly known. However, toxic cyanobacteria blooms could have a very important effect on wildlife. In particular, mass mortalities of waterbirds are receiving improved attention in recent years because of their increased occurrence. Cyanobacteria toxicosis by microcystins (potent hepatotoxic cyclic peptides) should be taken in account as a significant cause of such mortalities in eutrophic inland water systems. A suitable procedure to diagnose waterbird mortalities due to toxin-producing cyanobacteria (microcystins) should be based on five sequential steps: i) macroscopic in situ evaluation searching evidences of cyanobacteria blooms; ii) identification of toxic cyanobacteria species; iii) analysis of water samples searching for microcystin detection; iv) epidemiology and clinical sings; and v) post-mortem examination of waterbirds to verify that microcystins reach to digestive system of birds. This procedure was employed to analyze recent mortalities of waterbirds in Doñana National Park (S Spain), revealing that toxicosis by microcystins was the main cause of the worst mass mortality.Keywords. Cyanobacteria, diagnostic procedure, Doñana National Park, microcystins, waterbird mortalities, wildlife refuge.RESUMEN. Cianobacterias tóxicas y conservación de la vida salvaje: propuestas de un procedimiento para demostrar mortalidades en masa de avifauna causadas por microcistina. El papel que desempeñan las cianobacterias tóxicas en la conservación de la fauna salvaje está subestimado. Sin embargo, las proliferaciones de cianobacterias tóxicas pueden tener un efecto importante sobre la vida salvaje. Particularmente las mortandades masivas de aves acuáticas están siendo objeto de atención en los últimos años debido a su considerable incremento. Se debería tener en cuenta que las toxicosis cianobacterianas, especialmente por microcystinas (potentes peptidos hepatotóxicos), podrían ser una causa importante de mortalidad en aguas continentales. Un procedimiento adecuado para diagnosticar mortandades de aves acuáticas debidas a cianobacterias debería seguir un protocolo de cinco pasos: i) evaluación macroscópica in situ buscando evidencias de proliferación masiva de cianobacterias; ii) identificación de las especies de cianobacterias tóxicas; iii) análisis de muestras de agua para detectar microcystinas; iv) estudio de la epidemiología, y síntomas y signos clínicos; y v) examen post-mortem de las aves para verificar que las cianobacterias alcanzaron el sistema digestivo. Este procedimiento ha sido empleado para analizar los últimos casos de6M. A. Mateos-Sanz et al. mortandades de aves acuáticas en el Parque Nacional de Doñana (S España) revelando que la toxicosis pormicrocistinas fue la causa de la peor mortalidad masiva de aves en la última década.Palabras clave. Cianobacteria, microcistinas, mortalidad de aves acuáticas, Parque Nacional de Doñana, procedimiento diagnóstico, refugio de fauna salvaje.

scholarly journals An Autonomous Platform for Near Real-Time Surveillance of Harmful Algae and Their Toxins in Dynamic Coastal Shelf Environments

2021 ◽  
Vol 9 (3) ◽  
pp. 336
Author(s):  
Stephanie K. Moore ◽  
John B. Mickett ◽  
Gregory J. Doucette ◽  
Nicolaus G. Adams ◽  
Christina M. Mikulski ◽  
...  
Keyword(s):  
Real Time ◽  
Domoic Acid ◽  
Harmful Algae ◽  
Coastal Trapped Waves ◽  
Resource Managers ◽  
Bloom Formation ◽  
High Concentrations ◽  
Data Gap ◽  
Autonomous Technology

Efforts to identify in situ the mechanisms underpinning the response of harmful algae to climate change demand frequent observations in dynamic and often difficult to access marine and freshwater environments. Increasingly, resource managers and researchers are looking to fill this data gap using unmanned systems. In this study we integrated the Environmental Sample Processor (ESP) into an autonomous platform to provide near real-time surveillance of harmful algae and the toxin domoic acid on the Washington State continental shelf over a three-year period (2016–2018). The ESP mooring design accommodated the necessary subsystems to sustain ESP operations, supporting deployment durations of up to 7.5 weeks. The combination of ESP observations and a suite of contextual measurements from the ESP mooring and a nearby surface buoy permitted an investigation into toxic Pseudo-nitzschia spp. bloom dynamics. Preliminary findings suggest a connection between bloom formation and nutrient availability that is modulated by wind-forced coastal-trapped waves. In addition, high concentrations of Pseudo-nitzschia spp. and elevated levels of domoic acid observed at the ESP mooring location were not necessarily associated with the advection of water from known bloom initiation sites. Such insights, made possible by this autonomous technology, enable the formulation of testable hypotheses on climate-driven changes in HAB dynamics that can be investigated during future deployments.

scholarly journals LEAP-Based Greenhouse Gases Emissions Peak and Low Carbon Pathways in China’s Tourist Industry

2021 ◽  
Vol 18 (3) ◽  
pp. 1218
Author(s):  
Dandan Liu ◽  
Dewei Yang ◽  
Anmin Huang
Keyword(s):  
Greenhouse Gas ◽  
Global Climate ◽  
Ghg Emissions ◽  
Control Measures ◽  
Growth Potential ◽  
Planning System ◽  
Tourist Industry ◽  
Low Carbon ◽  
Carbon Reduction ◽  
Co2 Equivalent

China has grown into the world’s largest tourist source market and its huge tourism activities and resulting greenhouse gas (GHG) emissions are particularly becoming a concern in the context of global climate warming. To depict the trajectory of carbon emissions, a long-range energy alternatives planning system (LEAP)-Tourist model, consisting of two scenarios and four sub-scenarios, was established for observing and predicting tourism greenhouse gas peaks in China from 2017 to 2040. The results indicate that GHG emissions will peak at 1048.01 million-ton CO2 equivalent (Mt CO2e) in 2033 under the integrated (INT) scenario. Compared with the business as usual (BAU) scenario, INT will save energy by 24.21% in 2040 and reduce energy intensity from 0.4979 tons of CO2 equivalent/104 yuan (TCO2e/104 yuan) to 0.3761 Tce/104 yuan. Although the INT scenario has achieved promising effects of energy saving and carbon reduction, the peak year 2033 in the tourist industry is still later than China’s expected peak year of 2030. This is due to the growth potential and moderate carbon control measures in the tourist industry. Thus, in order to keep the tourist industry in synchronization with China’s peak goals, more stringent measures are needed, e.g., the promotion of clean fuel shuttle buses, the encouragement of low carbon tours, the cancelation of disposable toiletries and the recycling of garbage resources. The results of this simulation study will help set GHG emission peak targets in the tourist industry and formulate a low carbon roadmap to guide carbon reduction actions in the field of GHG emissions with greater certainty.

Knowledge about biosafety measures in clinical setting during the COVID-19 pandemic: a cross-sectional study with Brazilian dental students

2022 ◽  
pp. 1-25
Author(s):  
Matheus dos Santos Fernandez ◽  
Andreia Morales Cascaes ◽  
Francisco Wilker Mustafa Gomes Muniz ◽  
Nathalia Ribeiro Jorge da Silva ◽  
Camilla Hubner Bielavski ◽  
...  
Keyword(s):  
Clinical Setting ◽  
Knowledge Score ◽  
Cross Sectional Study ◽  
Dental Students ◽  
Control Measures ◽  
Practical Training ◽  
Sectional Study ◽  
Cross Sectional ◽  
Explanatory Variables ◽  
Medium Level

Abstract Objective: To evaluate the knowledge of Brazilian dental students about biosafety measures that should be adopted in the clinical setting during the coronavirus disease-2019 (COVID-19) pandemic. Methods: A cross-sectional study with 1,050 dental students was conducted. A semi-structured questionnaire was shared with students. Mean knowledge score on biosafety guidelines during the COVID-19 pandemic was the outcome, with a maximum of 8 scores. Explanatory variables included sociodemographic and educational characteristics, aspects related to biosafety education, actions adopted by the dental schools during the pandemic, and sources of biosafety information. Multivariate linear regression analyses were performed. Results: Mean knowledge score was 5.19 (1.28). Female students (β=0.346; 95%CI:0.154–0.539), those enrolled in the intermediate (β=0.525; 95%CI:0.167–0.883) or final (β=0.569; 95%CI:0.200–0.937) stage of course, and those who had already received theoretical-practical training in biosafety (β=0.464; 95%CI:0.063–0.866) presented higher mean knowledge scores. Students who did not receive guidance on aerosol control measures before the pandemic (β=-0.324; 95%CI:-0.519–-0.130) had the lowest score. Conclusion: Students presented a medium level of knowledge about dental biosafety measures in the COVID-19 pandemic. Sociodemographic characteristics and those related to the institutional profile of the participants, and access to orientation and training in biosafety may influence their knowledge.

scholarly journals Multi-source SO<sub>2</sub> emissions retrievals and consistency of satellite and surface measurements with reported emissions

2017 ◽  
Author(s):  
Vitali Fioletov ◽  
Chris A. McLinden ◽  
Shailesh K. Kharol ◽  
Nickolay A. Krotkov ◽  
Can Li ◽  
...  
Keyword(s):  
Point Source ◽  
Single Point ◽  
Control Measures ◽  
Ozone Monitoring Instrument ◽  
So2 Emissions ◽  
Vertical Column ◽  
Wind Speeds ◽  
Surface Measurements ◽  
Best Fit

Abstract. Reported sulfur dioxide (SO2) emissions from U.S. and Canadian sources have declined dramatically since the 1990s as a result of emissions control measures. Observations from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite and ground-based in-situ measurements are examined to verify whether the observed changes from SO2 abundance measurements are quantitatively consistent with the reported changes in emissions. To make this connection, a new method to link SO2 emissions and satellite SO2 measurements was developed. The method is based on fitting satellite SO2 vertical column densities (VCDs) to a set of functions of OMI pixel coordinates and wind speeds, where each function represents a statistical model of a plume from a single point source. The concept is first demonstrated using sources in North America, and then applied to Europe. The correlation coefficient between OMI-measured VCDs (with a local bias removed) and SO2 VCDs derived here using reported emissions for 1° by 1° gridded data is 0.91 and the best-fit line has a slope near unity, confirming a very good agreement between observed SO2 VCDs and reported emissions. Having demonstrated their consistency, seasonal and annual mean SO2 VCD distributions are calculated, based on reported point-source emissions for the period 1980–2015, as would have been seen by OMI. This consistency is further substantiated as the emissions-derived VCDs also show a high correlation with annual mean SO2 surface concentrations at 50 regional monitoring stations.

scholarly journals Synergistic effects of UVR and simulated stratification on commensalistic phytoplankton–bacteria relationship in two optically contrasting oligotrophic Mediterranean lakes

2015 ◽  
Vol 12 (3) ◽  
pp. 697-712 ◽  
Author(s):  
P. Carrillo ◽  
J. M. Medina-Sánchez ◽  
C. Durán ◽  
G. Herrera ◽  
V. E. Villafañe ◽  
...  
Keyword(s):  
Global Climate Change ◽  
Bacterial Communities ◽  
Bacterial Production ◽  
Synergistic Effects ◽  
Global Climate ◽  
Oligotrophic Lakes ◽  
Carbon Demand ◽  
In Situ Experiments ◽  
Upper Mixed Layer

Abstract. An indirect effect of global warming is a reduction in the depth of the upper mixed layer (UML) causing organisms to be exposed to higher levels of ultraviolet (UVR, 280–400 nm) and photosynthetically active radiation (PAR, 400–700 nm). This can affect primary and bacterial production as well as the commensalistic phytoplankton–bacteria relationship. The combined effects of UVR and reduction in the depth of the UML were assessed on variables related to the metabolism of phytoplankton and bacteria, during in situ experiments performed with natural pico- and nanoplankton communities from two oligotrophic lakes with contrasting UVR transparency (high-UVR versus low-UVR waters) of southern Spain. The negative UVR effects on epilimnetic primary production (PP) and on heterotrophic bacterial production (HBP), intensified under increased stratification, were higher in the low-UVR than in the high-UVR lake, and stronger on the phytoplanktonic than on the heterotrophic bacterial communities. Under UVR and increased stratification, the commensalistic phytoplankton–bacteria relationship was strengthened in the high-UVR lake where excretion of organic carbon (EOC) rates exceeded the bacterial carbon demand (BCD; i.e., BCD : EOC(%) ratio < 100). This did not occur in the low-UVR lake (i.e., BCD : EOC(%) ratio > 100). The greater UVR damage to phytoplankton and bacteria and the weakening of their commensalistic interaction found in the low-UVR lake indicates that these ecosystems would be especially vulnerable to UVR and increased stratification as stressors related to global climate change. Thus, our findings may have important implications for the carbon cycle in oligotrophic lakes of the Mediterranean region.

scholarly journals An Effective Similar-Pixel Reconstruction of the High-Frequency Cloud-Covered Areas of Southwest China

2019 ◽  
Vol 11 (3) ◽  
pp. 336 ◽  
Author(s):  
Wenping Yu ◽  
Junlei Tan ◽  
Mingguo Ma ◽  
Xiaolu Li ◽  
Xiaojun She ◽  
...  
Keyword(s):  
Land Surface ◽  
High Frequency ◽  
Southwest China ◽  
Global Climate ◽  
Average Error ◽  
Balance Theory ◽  
High Temporal Resolution ◽  
Retrieval Accuracy ◽  
Southwest Region

With advantages of multispatial resolutions, a high retrieval accuracy, and a high temporal resolution, the satellite-derived land surface temperature (LST) products are very important LST sources. However, the greatest barrier to their wide application is the invalid values produced by large quantities of cloudy pixels, especially for regions frequently swathed in clouds. In this study, an effective method based on the land energy balance theory and similar pixels (SP) method was developed to reconstruct the LSTs over cloudy pixels for the widely used MODIS LST (MOD11A1). The southwest region of China was selected as the study area, where extreme drought has frequently occurred in recent years in the context of global climate change and which commonly exhibits cloudy and foggy weather. The validation results compared with in situ LSTs showed that the reconstructed LSTs have an average error < 1.00 K (0.57 K at night and -0.14 K during the day) and an RMSE < 3.20 K (1.90 K at night and 3.16 K in the daytime). The experiment testing the SP interpolation indicated that the spatial structure of the LST has a greater effect on the SP performance than the size of the data-missing area, which benefits the LST reconstruction in the area frequently covered by large clouds.

Spatial variability and temporal dynamics of cyanobacteria blooms and water quality parameters in Missisquoi Bay (Lake Champlain)

2019 ◽  
Vol 19 (5) ◽  
pp. 1500-1506 ◽  
Author(s):  
I. Melendez-Pastor ◽  
E. M. Isenstein ◽  
J. Navarro-Pedreño ◽  
M-H. Park
Keyword(s):  
Total Phosphorus ◽  
Temporal Dynamics ◽  
Secchi Depth ◽  
Spatial Association ◽  
Phosphorus Concentration ◽  
Lake Champlain ◽  
Total Phosphorus Concentration ◽  
Cyanobacteria Bloom ◽  
Explanatory Variables ◽  
Cyanobacteria Blooms

Abstract Cyanobacteria bloom events have been associated with eutrophication processes, along with hydrologic and climate factors. Missisquoi Bay is a portion of Lake Champlain (USA–Canada) that is highly eutrophic and prone to cyanobacteria blooms and cyanotoxins. This study assessed the spatial–temporal influence of nutrients, turbidity and temperature in cyanobacteria distributions during a bloom event in the summer of 2006. Correlations, generalized linear models (GLMs), geostatistics and local indications of spatial association (LISA) autocorrelation analysis tested the influence of nutrient and non-nutrient explanatory variables in cyanobacteria biovolume. Total phosphorus exhibited a high direct correlation with cyanobacteria biovolume. The best performing GLMs included total phosphorus, total nitrogen, Secchi depth (as turbidity) and temperature as explanatory variables of cyanobacteria biovolume. Variogram analysis of those variables resulted in a better understanding of the underlying spatial variation process of the cyanobacteria bloom event. The LISA test revealed a moderate but stable autocorrelation between cyanobacteria biovolume and total phosphorus from 180 to 1,000 m of weight distance, suggesting the possibility of up-scaling the current results to coarse-resolution satellite imagery for more frequent monitoring of bloom events. The LISA test also revealed the spatial–temporal dynamic (movement of cyanobacteria scums) of high cyanobacteria blooms with high total phosphorus concentration.

scholarly journals Error Estimation of Pathfinder Version 5.3 Level-3C SST Using Extended Triple Collocation Analysis

2020 ◽  
Vol 12 (4) ◽  
pp. 590
Author(s):  
Korak Saha ◽  
Prasanjit Dash ◽  
Xuepeng Zhao ◽  
Huai-min Zhang
Keyword(s):  
Signal To Noise Ratio ◽  
Global Climate ◽  
Atmospheric Models ◽  
Science And Policy ◽  
Satellite Sst ◽  
Error Characterization ◽  
Essential Input ◽  
Ocean Forecasting ◽  
Mutually Independent

Sea Surface Temperature (SST) is an essential climate variable (ECV) for monitoring the state and detecting changes in the climate. The concept of ECVs, developed by the Global Climate Observing System (GCOS) program of the World Meteorological Organization (WMO), has been broadly adopted in worldwide science and policy circles Besides being a climate change indicator, the global SST field is an essential input for atmospheric models, air-sea exchange studies, understanding marine ecosystems, operational weather, and ocean forecasting, military and defense operations, tourism, and fisheries research. It is, therefore, critical to understand the errors associated with SST measurements from both in situ measurements and satellite observations. The customary way of validating a satellite SST is to compare it with in situ measured SSTs. This method, however, will have inaccuracies due to uncertainties involving both types of measurements. A triple collocation (TC) error analysis can be implemented on three mutually independent error-prone measurements to estimate the root-mean-square error (RMSE) of each measurement. In this study, the error characterization for the Pathfinder SST version 5.3 (PF53) dataset is performed using an extended TC (ETC) method and reported to be in the range of 0.31 to 0.37 K. These values are reasonable, as is evident from corresponding very high (~0.98) unbiased signal-to-noise ratio (SNR) values.

Year-class detection reveals climatic modulation of settlement strength in the European lobster, Homarus gammarus

2002 ◽  
Vol 59 (7) ◽  
pp. 1132-1143 ◽  
Author(s):  
M R.J Sheehy ◽  
R C.A Bannister
Keyword(s):  
Stock Assessment ◽  
Global Climate ◽  
Larval Settlement ◽  
European Lobster ◽  
Homarus Gammarus ◽  
Cross Correlation Analysis ◽  
Age Dependent ◽  
Intractable Problem ◽  
First Time

Understanding the nature of recruitment relationships in the European lobster, Homarus gammarus, has been an intractable problem because of difficulties associated with quantification of its scarce planktonic larvae and early benthic phase. We attempt to address this problem by analyzing the age composition of a population off the northeast coast of England. Age-dependent in situ deposits of neurolipofuscin in the eyestalk are used as an age index. An approach is presented that accounts and (or) corrects for the two most important potential sources of error in age determinations by this technique, namely environmental temperature variation and unexplained individual variation. This yields, for the first time in very long-lived clawed lobsters, reproducible catch age structures with year-class resolution. The method should be generally applicable to crustaceans. Cross-correlation analysis shows that larval settlement strength in the European lobster is associated with local sea temperatures and onshore winds in a manner similar to that reported for other lobsters. These findings have important implications for stock assessment, particularly the use of traditional models dependent on size and steady state, yield forecasting, the effects of global climate change, arguments about spawner protection or restocking, and the spawner–recruit relationship.

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