Aquatic publication review (20)

Effective water monitoring requires a well-designed measurement network. In an article published in Nature Sustainability, a team of U.S. researchers analyze the distribution of gauges in California’s river system and, based on this, suggest how water gauge networks can be designed to promote sustainable water management. We also zoom in on the results of a major international project, CELLDEX, which aimed to study the determinants of organic matter decomposition rates in rivers and streams around the globe. The conclusion that humans are indeed contributing to accelerating this process is not at all surprising. So is the fact that extreme phenomena in lakes, such as algal blooms, heat waves and low water levels, often co-occur, although the global patterns of their frequency vary.

The researchers report in Nature Communication. In contrast, a paper analyzing multi-year data on the impact of declining snow on the seasonality of stream flows and the dynamics of land-sea discharge helps verify the previous dogma that less snow means earlier stream flows. The phenomenon turns out to be much more complex. As we are drastically lacking water of drinkable quality, a team of German biochemists is presenting a new chitosan-based biomaterial that is effective in disinfecting water from bacteria. Finally, we recommend an intriguing article in which the author considers the thesis that recreational fishing has a lot in common with gambling.

1. strategic stream gauging network design for sustainable water management

Andrews L., Grantham T.E. (2024). Strategic stream gauging network design for sustainable water management. Nat Sustain.

We all know that rational and effective water management requires a well-designed measurement network that provides comprehensive and reliable information on the state of the environment. Improper placement of water gauges in the river network prevents accurate tracking of flows and significantly limits the ability to properly manage water resources. In an article published in Nature Sustainability, a pair of researchers from the University of California, Berkeley, USA, outline a holistic approach to designing a comprehensive watershed network with water management priorities in mind, including reservoir operations, biodiversity conservation and hydroclimate monitoring.

Applying this approach to the example of a river monitoring system in California, the researchers identified significant gaps in the current system and developed indications for reconfiguring meter locations. This work shows how water gauge networks can be designed to support sustainable water management. Unfortunately, the journal does not offer open access to the article, but it is definitely worth the effort to obtain it.

2. human activities shape global patterns of decomposition rates in rivers

Tiegs S.D., Capps K.A., Costello D.M.. et al. (2024). Human activities shape global patterns of decomposition rates in rivers. Science, eadn1262.

Rivers and streams contribute significantly to the global carbon cycle by decomposing huge amounts of terrestrial plant matter. Although they occupy less than 0.6 percent. of ice-free land surface, it receives 0.72 billion tons of carbon per year. However, the rate of matter decomposition in rivers varies widely, and the patterns and drivers of this process remain poorly understood. The problem was analyzed by a team of contractors from the Cellulose Decomposition Experiment (CELLDEX) project, consisting of nearly 150 researchers from around the world. The researchers used a standardized test(the cotton-strip test) to measure cellulose decomposition rates in 514 flowing water ecosystems at georeferenced locations on all seven continents and in each of Earth’s major terrestrial biomes. Cellulose decomposition is strongly influenced by many interacting environmental factors.

The models developed showed that the spatial patterns of cellulose distribution are highly heterogeneous and dependent on a characteristic combination of many factors. The most important variables were average daily water temperature, nitrogen and phosphorus availability, and average annual air temperature. Climate change, increased nutrient loading, transformation of catchment land use and changes in vegetation cover will accelerate the rate of organic matter decomposition in rivers and streams, resulting in reduced short-term carbon sequestration and transfer to long-term stores such as reservoirs, floodplains and oceans.

3. multivariate extremes in lakes

Woolway R.I., Tong, Y., Feng, L. et al. (2024). Multivariate extremes in lakes. Nat Commun 15, 4559.

It is said that misfortunes walk in pairs, and in the case of extreme events, even battalions. The term extreme refers to conditions beyond the accepted multi-year norm, and in the case of lakes, extreme events often include phenomena such as the occurrence of algal blooms, heat waves and low water levels. The researchers used literature data and satellite observations to analyze the co-occurrence of the three phenomena in more than 2,700. lakes around the world since the 1980s. In the 1970s. until now. During the analyzed period, 75 percent. of the lakes surveyed showed an increase in the frequency of simultaneous occurrence of at least two of the events under consideration, and in 25%. All three (in 5 percent the increase was significant).

Seemingly nothing new, since we know that the analyzed extremes in the lakes are interrelated, but the article presents a detailed analysis of the intensity of these phenomena in different geographic regions in connection with the risk of their occurrence. The greatest increase in the frequency of extreme events was observed in regions where an increase in the use of agricultural fertilizers, an increase in lake water temperatures and a decrease in water availability are recorded. As extreme events in lakes are a growing phenomenon, it is crucial to understand their interactions and effects on the ecosystem and to include them in future risk assessments.

4 Streamflow seasonality in a snow-dwindling world

Han J., Liu Z., Woods R. et al. (2024). Streamflow seasonality in a snow-dwindling world. Nature 629, 1075-1081.

An analysis of snowfall in the northern hemisphere over the past 70 years shows that snow moderates the impact of varying precipitation levels on river flows. Climate warming is causing snowfall in cold regions of the world to disappear and be replaced by rains, changing the dynamics of snowpack and, consequently, water flows. In a paper published in Nature, hydrologists from Tsinghua University in Beijing study how reduced snowpack will affect the seasonality of stream flows and the dynamics of land-to-sea discharge.

The authors used observations from more than 3,000. catchments in the northern hemisphere for which relevant data were available (covering the period 1950-2020). In addition to examining snowfall fractions, they analyzed two other measures: moment Q, expressed as the center of mass of streamflow(CTQ), which denotes the period of the year when 50 percent of the snowfall occurs. of annual Q, and the seasonal variation in the volume of Q, known as the “Q”. The streamflow concentration index(QCI), whose high values indicate high seasonal variability.

The authors showed that the average fraction of snowfall in the Northern Hemisphere has steadily declined over the 1950-2020 study period, which does not correspond to CTQ trends in all locations studied. However, the correlation with QCI was stronger. As the fraction of snowfall decreases, the time of the stream’s center of mass may accelerate or retard. Temporal changes in stream flow with decreasing snowfall fraction reveal a gradient from earlier stream flow in snow-rich catchments to delayed stream flow in less snowy catchments.

Moreover, the inter-annual and seasonal variability of streamflow timing increases as the fraction of snowfall decreases both in time and in space. The findings correct the previous heuristics of less snow means earlier streamflow and point to the complex dependence of seasonal streamflow regimes when snow is reduced.

5. biomaterial-based sponge for efficient and environmentally sound removal of bacteria from water

You Z., Lorente A., Marlina D. et al. (2024). Biomaterial-based sponge for efficient and environmentally sound removal of bacteria from water. Sci Rep 14, 12496.

Designing materials capable of disinfecting water without releasing harmful byproducts is still a challenge. A team of biochemists from the Free University of Berlin has presented a novel polycationic sponge material exhibiting strong antibacterial properties in the journal Scienitific Reports. It is made from chitosan derivatives and cellulose fibers. It is characterized by a highly porous structure obtained by cryo-gelation. For comparison purposes, the researchers synthesized a series of cryogels consisting of pure chitosan (CHI), chitosan with varying percentages of cationic quaternary ammonium groups, and cryogels with cellulose fibers.

The cryogels presented showed a reduction of up to 4-log (99.99 percent) against Gram-positive B. subtilis and Gram-negative E. coli within 6 hours. The incorporation of quaternary ammonium groups into chitosan significantly improved the bacterial adsorption and antimicrobial activity of the product, increasing its efficiency in reducing bacteria up to 4.5-log within 1 hour of incubation. This means that the material can disinfect more than 30 times more bacteria-contaminated water in 1 hour than it weighs by itself. The eco-friendly synthesis from water and readily available biomaterials, combined with the cost-effectiveness and simplicity of the technology, ensures the material’s versatility and potential for large-scale use in disinfection.

6. catch uncertainty and recreational fishing attraction: Propositions and future research directions

Arlinghaus R. (2024). Catch uncertainty and recreational fishing attraction: Propositions and future research directions. Fish and Fisheries00: 1-20.

The fishing season is in full swing, so finally it is worth introducing readers to an intriguing approach to interpreting the motives that drive us to engage in this activity. Why is fishing appealing to so many people? Because it has a lot to do with gambling. This is the thesis that ichthyologist Professor Robert Arlinhaus of the IGB in Berlin makes and tests based on an extensive literature review. Based on an analysis of publications in environmental psychology, neuroscience, anthropology, recreational fishermen’s motivational research, as well as popular fishing books, he argues that the main force motivating millions of people into recreational fishing is not the success of the catch, but its uncertainty.

In this view, fishing is a kind of challenge and is subject to rules derived from game theory. According to the author, the reasons why people engage in recreational fishing are largely different from those for commercial fishing and are primarily emotional. The interpretation presented in the article may contribute to explaining some well-known but difficult to explain phenomena, such as excessive investment of time and money in this activity (often exceeding the market value of the fish obtained), lack of self-regulation in terms of effort put into the activity with low fishing efficiency, suboptimal satisfaction despite increasing catch rates or even male dominance in the population of recreational anglers.

Such a non-dogmatic view of recreational fishing definitely opens up new avenues for exploring the phenomenon. Do avid anglers primarily become people with an increased propensity to gamble? Fascinating article at the intersection of psychology, ecology and economics with elements of game theory. I recommend, especially before the season!