Decay of Bloom-Forming Algae and the Affects on Dissolved Oxygen

 By: Andrea R. Ortiz 

The figure above is from Wang et. al., 2021. It indicates the algae strains a. A. catenella , b. P. donghaiense , c. S. costatum treatments and their results for 1. cell density, 2. dissolved oxygen concentration, and 3. Ammonia nitrogen concentration at each level surface = black, middle = red, and bottom = blue. 

 

Eutrophication is a process when an excess of minerals and nutrients occurs within a body of water. This sounds like a positive occurrence in theory; however the result of this process welcomes harmful algae blooms and a reduction of dissolved oxygen. The consequences of these overly enriched aquatic environments include destruction of ecosystems and massive loss of various aquatic species. 

In a 2020 study by Wang and colleagues, samples of Chinese costal water were used in order to evaluate the decay of bloom-forming algae and how it affects the reduction of dissolved oxygen (DO). 

Algae strains of A. catenella , P. donghaiense , S. costatum were cultured in a seawater medium under 24 day treatment involving stable temperature at 20 degrees Celsius and no light during incubation.

Interestingly enough the result of this investigation was that density and DO concentration of the algae decreased from each level formed in the tubes while ammonia nitrogen increased. This indicates that massive decay of harmful bloom-forming algae could cause increasing consumption of DO and over production of toxic ammonia nitrogen. Ultimately, it is imperative to further conduct future studies such as this in order prevent detrimental impacts to the world's various aquatic environments. 

Reference: 

Wang, Q., Li, X., Yan, T., Song, J., Yu, R., & Zhou, M. (2020). Laboratory simulation of dissolved oxygen reduction and ammonia nitrogen generation in the decay stage of harmful algae bloom. 

Journal of Oceanology and Limnology, 39(2), 500–507. https://doi.org/10.1007/s00343-020-9295-2 

SARS-CoV-2 EVERYWHERE?!

 By:Vianey Trevino

Daily SARS-CoV-2 produced in sewer by 1000 SARS-CoV-2 infected individuals from by shedding routes.

SARS-CoV-2 has been one of the biggest and changing viruses. Since the rise of this virus it has been detected in various places. Individuals infected with this virus shed genetic material by saliva, coughing and urine which is released into sewage and wastewater surveillance.Their research was focused on how SARS-CoV-2 RNA filled domestic wastewater was incoming by fecal shedding of SARS-CoV-2. They began their research by collecting urine, stool and sputum sewer contributions from infected and healthy individuals. They moved on to a “single shedder” where they focused on the contribution of saliva, sputum, stool and urine in four different scenarios. This is important since it still affects us today and the future since it will only help it increase.

Reference:

K. Crank, W. Chen, A. Bivins, S. Lowry, K. Bibby, Contribution of SARS-CoV-2 RNA shedding routes to RNA loads in wastewater, Science of The Total Environment, 2021,

Salt in Plants???

 By: Brisa C. Guerra

Effectiveness in soil microbial communities in easing plant salt stress. (Li, H., La, S., Zhang, X, et al., 2021)

When thinking of nature and salt we would assume the ocean or seawater where the particles of salt can easily be tasted, but in soil many of us would not think it be present there at all. As we all must know, soil carries many types of minerals and bacteria, but salt or levels of salinity is one of the main abiotic stressors that affect plants in specificity to crops. If not treated, the salinity levels can then cause many other problems such as many other stresses, nutritional disorders, and organ aging in plants. It was resulted that those plants who are salt resistant (SR) thrived better than those salt sensitive (SS) plants. It was shown that even though one type of plant had better production of growth, root-derived bacteria (RDB) did help the plant in positive ways by adapting to salinity. Despite being a plant being sensitive or being resistant to saline, the RDB adapted the plants well enough to promote growth and overcome the challenge. This is important because humans rely on agriculture through our daily lives mainly through what we eat. Based on what was found within this experiment, the next step could be finding a way to manage salinity on a bigger scale such as field crop productions. Overall, crops are a necessity for humans and without managing the salt levels on the fields, it can eventually affect production as a whole.

Citation:

Li, H., La, S., Zhang, X. et al. (2021) Salt-induced recruitment of specific root-associated bacterial consortium capable of enhancing plant adaptability to salt stress. ISME J 15, 2865-2882 

Green Algae Indirectly Threatens Water Quality

By: Melissa Villarreal 

The figure shows the relationship of the population density of Chlorella (green algae) with Microcystis (cyanobacteria) under different concentrations of hydrogen peroxide. A higher density of green algae protects cyanobacteria more effectively. Figure taken from Weenink et al. 2021.

Protecting our ever-diminishing drinking water and fresh body water is crucial for our growing population. A significant threat to water quality are cyanobacteria, and finding methods to combat them is essential. A study by Weenink and colleagues (2021) mentioned that cyanobacteria are responsible for toxic blooms, which threaten the water quality of freshwater lakes and reservoirs. This has a significant impact on the safety of drinking water, recreation, and irrigation water. Because cyanobacteria are very sensitive to hydrogen peroxide, this is a standard treatment used to diminish their presence and combat toxic blooms. Low concentrations of hydrogen peroxide are enough to control cyanobacteria while protecting the ecosystem of the water source. However, green algae, which is commonly found in freshwater, efficiently degrades hydrogen peroxide. Thus, green algae indirectly protect the cyanobacteria from the hydrogen peroxide, making the treatment ineffective. As shown in the figure, cyanobacteria can survive in high levels of hydrogen peroxide in the presence of green algae. So, the higher the population of green algae, the higher rates of survival of cyanobacteria. Unfortunately, using too high concentration of hydrogen peroxide to counteract the green algae can have a negative effect on the environment and ecosystem. Therefore, it is vital to find methods to effectively combat cyanobacteria to protect our water sources while preserving the ecosystem. 

Original Article: 

Weenink, E.F.J., Matthijs, H.C.P., Schuurmans, J.M., Piel, T., Herk, M.J., Sigon, C.A.M., et al. (2021) Interspecific protection against oxidative stress: green algae protect harmful cyanobacteria against hydrogen peroxide. Environ Microbiol 23: 2404–2419.

Effect of Invasive Species on Plant-Soil Fungal Diversity

 By: Maria Hernandez

The experimental setup with representations of the different plant species used. Native plant species are represented by grass-shaped symbols. Invasive plant species can be identified by the orange triangles. Each setup consisted of different number of native species (1, 2, 4 or 8) and one type of invasive species. Figure taken from Shen et al. 2021.

Climate change has the potential of increasing both the spread and establishment of invasive plant species across the world. Plant invasions can affect an ecosystem's stability as well as alter the community structure between soil and native plants (McCann 2000; Van der Putten et al., 2007). While previous studies showed that communities with more plant and soil fungal diversity were more resistant to plant invasions (Elton 1958), a study conducted by Shen and colleagues suggests a more positive resistance relationship between plant-soil microbial diversity. The study shows that when there are no plant invasions, plant diversity has an indirect effect on soil fungal diversity by increasing soil total carbon (TC). However, when plant invasions were detected, plant diversity had a more direct effect. Although the study shows the relationship between plant-soil fungal diversity both with and without plant invasions, further research is still needed to understand the ecological mechanisms that are behind both diversity-diversity and diversity-stability relationships. The study, however, adds on to the previous knowledge about both the aboveground and belowground diversity relationships. By showing the effect of invasive plant species on plant-soil microbial diversity, the study can aid in future scientific research on invasive plants and climate change.

Article:

Shen C., Wang J., He J.Z., Yu F.H., and Ge Y. (2021). Plant Diversity Enhances Soil Fungal Diversity and Microbial Resistance to Plant Invasion. Applied and Environmental Microbiology.

The impact of soil erosion on soil fertility and vine vigor

Fig: Soil Organic Carbon and weight of prune residue (Novara et al. 2018)

Soil is the most important natural resources for food production. Unfortunately, due to human induced cause like land degradation, it is causing soil erosion. Erosion impacts crop yields and threatens soil system (Mol and Keesstra, 2012). Erosion also leads to loss of nutrients, decrease thickness of soil level and lower soil water holding capacity (García-Díaz et al. 2017; Li et al., 2016). In Europe wheat yield losses ranged from 0.04% year and 0.67% year in Australia (Cerdà et al., 2017, Den Biggelaar et al. 2003). Researcher Agata Novara and her colleagues conducted a research to analyze the interactions among vines vigor, sediment delivery and soil organic carbon (SOC) in a sloping vineyard. Their results confirmed that soil erosion, sediment redistribution and SOC across the slope strongly affected by topographic features and curvature. To avoid the negative effects of soil fertility reduction on plant vigor, farmers can increase the use of external input which lead to a decrease of yield sustainability. In order to maintain the yield sustainability, we should control soil erosion and can help increase yield sustainability.

Original article:
Novara, A., Pisciotta, A., Minacapilli, M., Maltese, A., Capodici, F., Cerdà, A., & Gristina, L. (2018). The impact of soil erosion on soil fertility and vine vigor. A multidisciplinary approach based on field, laboratory and remote sensing approaches. Science of The Total Environment, 622-623, 474–480. doi:10.1016/j.scitotenv.2017.11.272 

Are we making our life endangered by drinking water?

Figure: Drinking water system (Su, H.-C et al. 2018)

Antibiotics not only play as a therapeutic drug for human beings but also for aquaculture, livestock and farming. With the excessive use of antibiotics, it has made the environment contaminated by antibiotic resistant bacteria, antibiotic residues, antibiotic resistance genes (ARG). Since the rise of environmental contaminants, the antibiotic resistance genes (ARG) were detected in various places in our environment such as hospital wastewater, wastewater treatment plants, chicken, beef, pork, dairy. These ARGs can transfer to humans by drinking water sources and endangering human life. Su, H.-C and his colleagues conducted a research to investigate and occurrence and diversity of ARGs in source water, water treatment plants and tap water. Their research showed that 27 different ARGs were present in those water sources. The total abundance of the detected ARGs in tap water was much lower than that in source water. Sand filtration and sedimentation in drinking water treatment plants could effectively remove ARGs. It was found that Pseudomonas may be involved in the proliferation and dissemination of ARGs in the studied drinking water treatment system. It could be noted that sedimentation and sand filtration could be effective methods for removing ARGs in aquatic systems.



Original article:
Su, H.-C., Liu, Y.-S., Pan, C.-G., Chen, J., He, L.-Y., & Ying, G.-G. (2018). Persistence of antibiotic resistance genes and bacterial community changes in drinking water treatment system: From drinking water source to tap water. Science of The Total Environment, 616-617, 453–461. doi:10.1016/j.scitotenv.2017.10.318