An introduction to the 'micronet' of cyanobacterial harmful algal blooms (CyanoHABs): cyanobacteria, zooplankton and microorganisms: a review

2020 ◽  
Vol 71 (5) ◽  
pp. 636 ◽  
Author(s):  
Elżbieta Wilk-Woźniak

Cyanobacterial harmful algal blooms are known all around the world. Climate change (temperature increase) and human activity (eutrophication) are factors that promote the proliferation of cyanobacteria, leading to the development of blooms and the release of toxins. Abiotic and biotic factors are responsible for the development of blooms and how long they last. Although the abiotic factors controlling blooms are well known, knowledge of biotic factors and their interactions is still lacking. This paper reviews five levels of biotic interactions, namely cyanobacteria–zooplankton, cyanobacteria–ciliates, cyanobacteria–bacteria, cyanobacteria–viruses and cyanobacteria–fungi, showing a more complex food web network than was previously thought. New findings published recently, such as the relationships between cyanobacteria and viruses or cyanobacteria and fungi, indicate that cyanobacterial blooms are not the end of the cycle of events taking place in water habitats, but rather the middle of them. As such, a new approach needs to consider mutual connections, genetic response, horizontal gene transfer and non-linear flow of carbon.

Oecologia ◽  
2020 ◽  
Vol 194 (4) ◽  
pp. 529-539
Author(s):  
Leslie J. Potts ◽  
J. D. Gantz ◽  
Yuta Kawarasaki ◽  
Benjamin N. Philip ◽  
David J. Gonthier ◽  
...  

AbstractSpecies distributions are dependent on interactions with abiotic and biotic factors in the environment. Abiotic factors like temperature, moisture, and soil nutrients, along with biotic interactions within and between species, can all have strong influences on spatial distributions of plants and animals. Terrestrial Antarctic habitats are relatively simple and thus good systems to study ecological factors that drive species distributions and abundance. However, these environments are also sensitive to perturbation, and thus understanding the ecological drivers of species distribution is critical for predicting responses to environmental change. The Antarctic midge, Belgica antarctica, is the only endemic insect on the continent and has a patchy distribution along the Antarctic Peninsula. While its life history and physiology are well studied, factors that underlie variation in population density within its range are unknown. Previous work on Antarctic microfauna indicates that distribution over broad scales is primarily regulated by soil moisture, nitrogen content, and the presence of suitable plant life, but whether these patterns are true over smaller spatial scales has not been investigated. Here we sampled midges across five islands on the Antarctic Peninsula and tested a series of hypotheses to determine the relative influences of abiotic and biotic factors on midge abundance. While historical literature suggests that Antarctic organisms are limited by the abiotic environment, our best-supported hypothesis indicated that abundance is predicted by a combination of abiotic and biotic conditions. Our results are consistent with a growing body of literature that biotic interactions are more important in Antarctic ecosystems than historically appreciated.


Environments ◽  
2019 ◽  
Vol 6 (6) ◽  
pp. 60 ◽  
Author(s):  
Igor Ogashawara

Cyanobacterial harmful algal blooms (CHABs) have been a concern for aquatic systems, especially those used for water supply and recreation. Thus, the monitoring of CHABs is essential for the establishment of water governance policies. Recently, remote sensing has been used as a tool to monitor CHABs worldwide. Remote monitoring of CHABs relies on the optical properties of pigments, especially the phycocyanin (PC) and chlorophyll-a (chl-a). The goal of this study is to evaluate the potential of recent launch the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 satellite to identify PC and chl-a. To do this, OLCI images were collected over the Western part of Lake Erie (U.S.A.) during the summer of 2016, 2017, and 2018. When comparing the use of traditional remote sensing algorithms to estimate PC and chl-a, none was able to accurately estimate both pigments. However, when single and band ratios were used to estimate these pigments, stronger correlations were found. These results indicate that spectral band selection should be re-evaluated for the development of new algorithms for OLCI images. Overall, Sentinel 3/OLCI has the potential to be used to identify PC and chl-a. However, algorithm development is needed.


2000 ◽  
Vol 51 (1) ◽  
pp. 73 ◽  
Author(s):  
Mark A. Siebentritt ◽  
George G. Ganf

Distribution of the emergent macrophytes Bolboschoenus medianus and Bolboschoenus caldwellii is dominated by the latter at regions higher on the elevation gradient, whereas the former is dominant further down the gradient. Monocultures and mixtures of plants were grown across a water-depth gradient in experimental ponds to determine whether distribution is due to abiotic factors, biotic factors, or a combination of both. Monocultures of each species tolerated exposure, showing little variation in relative growth rate (RGR), net assimilation rate (NAR) or leaf area ratio (LAR). Survival when initially flooded was dependent on shoot height. Plants surviving inundation responded by increasing height through reallocation of biomass. The RGR of B. medianus was maintained across the water-depth gradient by increasing NAR as LAR declined. The RGR of B. caldwellii beyond a depth of −20 cm declined because reductions in LAR were not paralleled by increases in NAR. Mixtures of species growing at 20 cm and 0 cm indicated that biotic interactions occurred and that B. caldwellii was the dominant species. Neither species dominated at −60 cm, presumably because this was beyond the depth tolerated by both species. The study suggests that the zonation of B. medianus and B. caldwellii is attributable to a combination of both abiotic and biotic factors.


2019 ◽  
Vol 2 (1) ◽  
pp. 6 ◽  
Author(s):  
Anjana Chamilka Thuduhena

Abstract   Cyanobacterial Harmful Algal blooms (CHABs) cause devastating impacts to fisheries, tourism, public health and ecosystem around the world, and have increased in frequency. Cyanobacterial blooms occur in fresh water and marine environments, producing a variety of toxins, and poisoning risks to humans and animals. Chemicals can be used to kill cyanobacteria. Unfortunately, many of these chemicals are toxic to other forms of life, including fish and organisms they eat. The use of chemicals in natural lakes could create more problems than they solve, is not permitted. Cyanophage is a double-stranded DNA virus that infects cyanobacteria and is detected in both freshwater and marine environments as a biological solution developed Cyanophages can use for long term treatment options.   Key words:   Cyanobacterial Harmful Algal blooms, Cyanophage, DNA Viruses  


2020 ◽  
Vol 12 (5) ◽  
pp. 868 ◽  
Author(s):  
Abhishek Kumar ◽  
Deepak R. Mishra ◽  
Nirav Ilango

The Landsat 8 Operational Land Imager (OLI) has a panchromatic band (503–676 nm) that can be used to derive a novel virtual orange band (590–635 nm) by using the multispectral green band and red band components. The orange band is useful for the accurate detection and quantification of phycocyanin (PC), an accessory pigment in toxin-producing cyanobacterial blooms, because of the specific light absorption characteristics of PC around 600–625 nm. In this study, we compared the Landsat 8 OLI’s and Sentinel-3 Ocean and Land Color Instrument’s (OLCI) derived orange band reflectance and PC products corresponding to a same-date overpass during a severe cyanobacterial bloom in Lake Erie, USA. The goal was to determine if the OLI’s virtual orange band can produce results equivalent to the OLCI’s actual orange band. Band-by-band match-ups used the OLI’s top-of-atmosphere (TOA) reflectance versus TOA reflectance from the OLCI, and surface reflectance (SR) from the OLI versus SR from the OLCI. A significant correlation was observed between the OLI’s and OLCI’s derived orange band TOA reflectance (R2 = 0.86; p < 0.001; NRMSE = 9.01%) and orange band SR (R2 = 0.93; p < 0.001; NRMSE = 20.23%). The PC map produced using the best-fit empirical models from both sensors showed similar PC spatial patterns and concentration levels in the western basin of Lake Erie. The results from this research are particularly important for the study of smaller inland waterbodies with the 30 m resolution of the OLI, which cannot be studied with the 300 m resolution of OLCI data, and for analyzing historical bloom events before the launch of the OLCI. Although more analysis and validation need to be conducted, this study opens up Landsat 8’s applicability in research on cyanobacterial harmful algal blooms (cyanoHABs).


Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 471
Author(s):  
Roberta Teta ◽  
Gerardo Della Sala ◽  
Germana Esposito ◽  
Mariano Stornaiuolo ◽  
Silvia Scarpato ◽  
...  

Cyanobacteria are ubiquitous photosynthetic microorganisms considered as important contributors to the formation of Earth’s atmosphere and to the process of nitrogen fixation. However, they are also frequently associated with toxic blooms, named cyanobacterial harmful algal blooms (cyanoHABs). This paper reports on an unusual out-of-season cyanoHAB and its dynamics during the COVID-19 pandemic, in Lake Avernus, South Italy. Fast detection strategy (FDS) was used to assess this phenomenon, through the integration of satellite imagery and biomolecular investigation of the environmental samples. Data obtained unveiled a widespread Microcystis sp. bloom in February 2020 (i.e., winter season in Italy), which completely disappeared at the end of the following COVID-19 lockdown, when almost all urban activities were suspended. Due to potential harmfulness of cyanoHABs, crude extracts from the “winter bloom” were evaluated for their cytotoxicity in two different human cell lines, namely normal dermal fibroblasts (NHDF) and breast adenocarcinoma cells (MCF-7). The chloroform extract was shown to exert the highest cytotoxic activity, which has been correlated to the presence of cyanotoxins, i.e., microcystins, micropeptins, anabaenopeptins, and aeruginopeptins, detected by molecular networking analysis of liquid chromatography tandem mass spectrometry (LC-MS/MS) data.


Harmful Algae ◽  
2017 ◽  
Vol 68 ◽  
pp. 168-177 ◽  
Author(s):  
Xiaomei Su ◽  
Alan D. Steinman ◽  
Xiangming Tang ◽  
Qingju Xue ◽  
Yanyan Zhao ◽  
...  

2018 ◽  
Vol 43 (1) ◽  
pp. 24-45 ◽  
Author(s):  
Hannah R Miller ◽  
Stuart N Lane

Matthews’ 1992 geoecological model of vegetation succession within glacial forefields describes how following deglaciation the landscape evolves over time as the result of both biotic and abiotic factors, with the importance of each depending on the level of environmental stress within the system. We focus in this paper on how new understandings of abiotic factors and the potential for biogeomorphic feedbacks between abiotic and biotic factors makes further development of this model important. Disturbance and water dynamics are two abiotic factors that have been shown to create stress gradients that can drive early ecosystem succession. The subsequent establishment of microbial communities and vegetation can then result in biogeomorphic feedbacks via ecosystem engineering that influence the role of disturbance and water dynamics within the system. Microbes can act as ecosystem engineers by supplying nutrients (via remineralization of organic matter and nitrogen fixation), enhancing soil development, either decreasing (encouraging weathering) or increasing (binding sediment grains) geomorphic stability, and helping retain soil moisture. Vegetation can act as an ecosystem engineer by fixing nitrogen, enhancing soil development, modifying microbial community structure, creating seed banks, and increasing geomorphic stability. The feedbacks between vegetation and water dynamics in glacial forefields are still poorly studied. We propose a synthesized model of ecosystem succession within glacial forefields that combines Matthews’ initial geoecological model and Corenblit's model to illustrate how gradients in environmental stress combined with successional time drive the balance between abiotic and biotic factors and ultimately determine the successional stage and potential for biogeomorphic feedbacks.


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