Aquatic publication review (11)

Although you may not see it outside the window, we are in the midst of winter, so the current literature review is devoted in large part to papers on glaciers and climate change – a timely topic. However, we will start with a publication with rather controversial overtones for many of us, because it proves that water salinity can reduce greenhouse gas emissions. Instead, it is not constrained by global warming, which is contributing to the melting of the ice cap and the release of the methane imprisoned beneath it. And we have a feedback loop: according to the puff principle, “the more, the more.”

As a result of melting, glaciers not only release the greenhouse gases imprisoned in them, but also lose their peculiar paleoarchives, or deposits of trapped aerosol particles. Their irrevocable loss deprives us of the opportunity to recreate historical scenarios. You will also read a report on the global decline in groundwater levels, which has been proven by a study of some 170,000. Wells. We also present a new index of agricultural pressure on the ecological status of rivers in Europe, which takes into account not only the traditional share of agricultural land in the catchment, but also a number of factors determining the intensity of this pressure. And finally, about the need to protect little-transformed rivers, such as those in the Biebrza National Park, as they are still important refuges for many species of aquatic flora and fauna.

1. salinity causes widespread restriction of methane emissions from small inland waters

Soued C., Bogard M.J., Finlay K. et al. (2024). Salinity causes widespread restriction of methane emissions from small inland waters. Nat Commun 15, 717.

Salinity in inland waters is seen (and rightly so) as an environmental problem, especially if caused by human activity. However, it turns out that salt in water can also play a positive role – as a regulator of methane (_CH4) emissions, a potent greenhouse gas. Inland waters are one of its largest sources, but the models and emission estimates currently in operation were developed for solute-poor ecosystems and may not be applicable to salt-rich inland waters. It turns out that existing models overestimate _CH4 emissions from small reservoirs and wetlands by up to several orders of magnitude, and these discrepancies can be linked precisely to salinity levels. This was proven by Canadian scientists based on studies of water quality parameters and _CH4 emission rates in nearly 200 aquatic ecosystems of various categories across the Canadian Prairies. According to estimates, failure to account for the salinity factor led to an overestimation of emissions from the area’s small watersheds by at least 81 percent. ( ~ 1 Tg ^year-1_CO2 equivalent), an amount comparable to other major national emission sources. The presence of solutes (primarily sulfate) modifies the carbon mineralization process carried out by methanogens and methanotrophs (microorganisms that engage methane in respiration), reducing the amount of _CH4 through several metabolic processes. This means that the widespread salinity of inland waters can affect the _CH4 cycle and should be taken into account in future projections of emissions to the aquatic environment. Let’s just hope it doesn’t occur to someone to recommend salting as a remedy for methane emissions!

2. permafrost trapped natural gas in Svalbard, Norway

Birchall T., Jochmann M., Betlem P. et al. (2023). Permafrost trapped natural gas in Svalbard, Norway. Front. Earth Sci. 11:1277027. doi: 10.3389/feart.2023.1277027

Increased greenhouse gas emissions and the resulting threat flow not only from aquatic ecosystems, but also from glaciers. Millions of cubic meters of methane-containing natural gas are trapped under the layer of permafrost covering the Svalbard archipelago. Scientists at the Svalbard University Center have just reported on Frontiers of Earth Science a disturbing discovery – gas trapped under the ice sheet may be moving. It turns out that permafrost is heterogeneous in its structure and in higher mountain areas it is not at all as tight as it might seem. This means that methane can escape from under the ice. Currently, gas escape is low, but factors such as glacier retreat and permafrost melt could lead to increased emissions. This, in turn, will accelerate warming and, by way of feedback, lead to an even more intense release of methane. At the moment, scenarios for the intensification of this phenomenon are not yet known, but scientists warn of its potential impact on the climate.

3. high-altitude glacier archives lost due to climate change-related melting

Huber C.J., Eichler A., Mattea E. et al. (2024). High-altitude glacier archives lost due to climate change-related melting. Nat. Geosci.

As a result of melting, glaciers lose not only the greenhouse gases trapped in them, but also the archives. Ice formations located at high altitudes are unique natural stores for reconstructing climate and environmental changes. They accumulate in their deposits and store aerosol particles that float in the atmosphere for only a few days. Such paleoarchives make it possible to reconstruct information on atmospheric composition, temperature, precipitation, droughts, fires, industrial pollution or vegetation composition (pollen). However, as a result of mass loss due to global warming, these archives of the past are under threat. Researchers from the University of Bern demonstrated this by comparing two firn cores taken in 2018 and 2020 from the Corbassière glacier in the western Swiss Alps. Stable isotope analysis of oxygen, ammonium nitrogen, nitrate and sulfate showed differences between cores, which the authors clearly link to the melting phenomenon. According to the researchers, the lower deposition reading suggests that ions in the melt percolation pathway have either been moved to deeper layers or removed completely. These results indicate that the glacier is irretrievably lost as an archive of major atmospheric aerosol components.

4. rapid groundwater decline and some cases of recovery in aquifers globally

Jasechko S., Seybold H., Perrone D. et al. (2024). Rapid groundwater decline and some cases of recovery in aquifers globally. Nature 625, 715-721.

With climate change, we are losing not only the archives trapped in glaciers, but especially the water stored there. Recent worldwide studies indicate that the problem of declining groundwater levels is widespread. The researchers analyzed trends of change using data from some 170,000. Monitoring wells and nearly 1,700. aquifer systems in more than 40 countries, which are responsible for about 75 percent. world groundwater intake. They showed that significant declines in water levels (more than 0.5 meters per year) are now a common phenomenon, and have unfortunately accelerated by as much as 30 percent over the past four decades. regional aquifers around the world. This was especially true in areas with the greatest precipitation deficit, which limits the possibility of recovery. The authors also present examples (from Thailand, Iran or Arizona in the United States) where these negative trends have been reversed as a result of policy changes, controlled aquifer replenishment, water diversion or proper formal and legal regulations (groundwater extraction fees and well licensing). These examples show that depleting aquifer systems can be regenerated with proper resource management.

5. river ecological status is shaped by agricultural land use intensity across Europe

Schürings Ch., Globevnik L., Lemm J. U. et al. (2024). River ecological status is shaped by agricultural land use intensity across Europe, Water Research, 251, 121136,

Not only do we have less and less water, but we are also working hard to deteriorate its quality. The impact of agriculture on the ecological status of waters has been proven many times and is probably no longer disputed anywhere. Agriculture affects waters through the supply of nutrients and chemical pollutants, water abstraction or hydromorphological changes. However, most researchers, when analyzing this impact, use a simple indicator that determines the share of land in agricultural use in the catchment. And yet agriculture is unequal to agriculture, as the types of agricultural activities and practices that determine the intensity of these pressures vary strongly within Europe. A team of scientists has developed a more precise index of agricultural intensity, integrating characteristics such as nutrient balance, exposure to pesticides, the amount of water withdrawal for agricultural irrigation and the proportion of land used for agriculture in the riparian zone. On this basis, 20 Areas of Farming-induced Freshwater Pressures(AFFP) of varying intensity of impact have been identified in Europe. The strongest agricultural pressures were found for high-intensity cropland in the Mediterranean and temperate regions, while the lowest were characterized by extensive grassland and fallow land in the northern and mountainous regions, as well as low-intensity mosaic crops. Links between the indicator and ecological status were tested using data from EU countries’ reports on river basin management plans from 2010-2015, available for more than 50,000. catchment units of European rivers. Using AFFP, correlations with ecological status were twice as high as when only the share of agriculture in the catchment was considered. The results identify regions of Europe with high agricultural pressure on river biodiversity and show that taking agricultural intensity into account can significantly increase the strength of the correlation with ecological status.

6. Observed and estimated taxonomic diversity of different groups of aquatic organisms in the pristine rivers in the Biebrza National Park.

Pietruczuk K., Budka A., Andrzejewski W. et al. (2023). Observed and estimated taxonomic diversity of different groups of aquatic organisms in the pristine rivers in the Biebrza National Park, Ecohydrology & Hydrobiology, (in press).

And finally, a report on the state of conservation of our native aquatic ecosystems, this time using the rivers of the Biebrza National Park as an example. In Ecohydrology & Hydrobiology, a team of Polish scientists presented the results of a study conducted in 2021 at 25 study sites, where the taxonomic composition of all five groups of organisms used in assessing the ecological status of rivers – benthic diatoms, phytoplankton, macrophytes, benthic macroinvertebrates and ichthyofauna – was identified. The aim of the study was to identify the taxonomic resources of the area’s river network and compare the biodiversity of various aquatic organisms, as well as to assess the field effort required to identify the entire pool of taxa inhabiting the study area. Phytoplankton (475 taxa) and benthic macroinvertebrates (308) showed the greatest diversity in terms of taxonomy. The diatom periphyton included 151 species, macrophytes 72 taxa, and the ichthyofauna assemblage included 24 species. Analysis of the researcher’s effort required to discover 80 percent, 90 percent and 100 percent of the predicted diversity using the asymptotic taxonomic richness estimator Chao2 showed that if the field work had continued, another 110 taxa of phytoplankton, 104 taxa of benthic macroinvertebrates, 40 species of diatoms, 9 species of macrophytes and 2 species of fish would have been recorded in the BNP. Alpha diversity was found to be high, but gamma diversity – relatively low due to the homogeneous nature of the studied rivers (low beta diversity). The authors showed that the analyzed section of the Biebrza valley includes valuable natural resources, including many protected species of plants and animals.