Polski
A current review of the aquatic literature brings new information on golden algae – Polish scientists have used bioassays to test how water samples taken from the Oder River during the disaster affect plankton organisms. Another team of national scientists looked at the problem of metal pollution in the waters of the Vistula Lagoon and the role of phytoplankton in their circulation in this ecosystem. The theme of the impact of climate change on aquatic organism assemblages could not be missed either. This time we present the problem of remodeling coral reef fish assemblages and their tropicalization in subtropical areas.
The researchers also asked themselves how to assess the impact of changes in groundwater levels on the health of water-dependent ecosystems. Imaging information and relevant indicators are proving helpful in mapping areas at risk of drought due to lowered groundwater. Another indicator that can effectively support rational resource management is the Urban Nature Index, which is used to assess the ecological footprint of urbanized areas. This is an interesting proposition for city managers facing the need to adapt to climate change.
1. primnesium as a threat for planktonic communities – an ecotoxicological approach for the environmental disaster in the Oder River 2022
Szklarek S., Font-Nájera A., Mazur-Marzec H. et al. 2024. primnesium as a threat for planktonic communities – an ecotoxicological approach for the environmental disaster in the Oder River 2022. Ecohydrology & Hydrobiology
The environmental disaster that hit the Oder River in the summer of 2022. has made the problematic golden algae has become firmly established in our domestic scientific literature. And very well, because we still know very little about this dangerous algae. And there is especially little research on the effects of toxic Prymnesium parvum blooms on organisms other than fish. Researchers from Polish centers undertook an assessment of the toxicological effects of P. parvum blooms by subjecting river water samples to microbiotests involving organisms from two trophic levels: producers (the green alga Pseudokirchneriella subcapitata) and consumers (two species of crustaceans Daphniamagna and Thamnocephalus platyurus).
The water samples tested came from the Oder River from the period of the disaster (August 13-16, 2022) and just after (September 24). The ecotoxicity assessment showed significant differences in the responses of the plankton organisms tested. While the green alga P. subcapitata and one of the crustaceans T. platyurus did not show increased mortality in the presence of P. parvum and prymnesins in the samples, the daphnia D. magna proved sensitive to the disaster water, with a maximum mortality rate of up to 90 percent after 24 hours of exposure.
Analysis of the 18S rRNA gene showed high levels of P. parvum in the samples tested during the environmental disaster (up to 9.2 percent) and their drastic decrease one month after the disaster (0.1 percent). The results of the study expand the knowledge of the impact of toxic P. parvum blooms on plankton communities and indicate that D. magna may be an effective bioindicator of the risk of golden algal blooms.
2. The role of planktonic filtrators in the distribution of metals in the water of semi-closed lagoon (southern Baltic)
Beldowska M., Kobos J., Nawrocka L. et al. 2024. The role of planktonic filtrators in the distribution of metals in the water of semi-closed lagoon (southern Baltic). Ecohydrology & Hydrobiology
In our waters, not only eutrophication, salinity and P. parvum are significant problems. Also, metals are a group of environmental pollutants that require recognition of the processes determining their origin, migration pathways in the aquatic environment, distribution and seasonal dynamics. Polish scientists have analyzed the concentration of metals such as: beryllium (Be), thallium (Tl), mercury (Hg), cadmium (Cd), silver (Ag), lead (Pb), cobalt (Co), chromium (Cr), uranium (U), nickel (Ni), vanadium(V), molybdenum (Mo), aluminum (Al), zinc (Zn), manganese (Mn), copper (Cu), iron (Fe) and strontium (Sr), as well as other elements (among others.sodium, magnesium, calcium or potassium, among others) in samples taken between May 2017 and April 2018 at three sites within the Vistula Lagoon. In addition, they examined the taxonomic composition and biomass of phytoplankton.
Metals can be accumulated by phytoplankton. In particular, Pb, U, Co, Be, Zn, Cr, Sr, Ca, Al, Fe, Ni, Mg and Se show the ability to accumulate intensively. Thus, they are introduced into the first link of the food web. However, the amount and type of metals accumulated in the cells varied according to their size and taxon. This may be related to the specific structure of the cell or to the need for a chemical element with a specific role in the cell. The above observations indicate the specific properties of individual algal species affecting the selectivity of adsorption of elements from water.
Cyanobacteria of the order Oscillatoriales played the most important role in the circulation of dissolved elements in the Vistula Lagoon. The dying biomass sinks to the bottom, where it decomposes and becomes a secondary source of dissolved metals in the water, as was observed in the Lagoon after the spring phytoplankton bloom (increase in Pb, Ni and Mn concentrations). In turn, the process affecting the circulation of metals in estuaries was flocculation, which contributed to the vertical transport of Pb, Al, Fe, Mn, Cd and Be to the sediment surface. In this situation, bottom sediments are not only a sink for metals, but under certain conditions can also be a source of metals.
This is particularly important in shallow estuaries, where dissolved chemicals can be easily transported from the bottom zones into the water column and introduced into the cycle and trophic network. The article points out the role of phytoplankton in the circulation of hazardous metals in the water and sediments of the Vistula Lagoon.
3. Establishing ecological thresholds and targets for groundwater management
Rohde M.M., Stella J.C., Singer M.B. et al. 2024. Establishing ecological thresholds and targets for groundwater management. Nat Water
Groundwater is extremely important for the functioning of many ecosystems. However, requirements for their availability are rarely included in management and conservation plans for water-dependent ecosystems. A team of U.S. scientists has developed an approach to determine ecological thresholds, ecological targets and drought risk mapping for groundwater-dependent vegetation in California based on Landsat satellite data from 1985-2022 and the Normalized Differential Vegetation Index (NDVI).
Based on the analysis of changes in NDVI against changes in groundwater level (DTG) during the dry season, standardized using the Z index (an index indicating the number of standard deviations by which a given value differs from the mean; Z-score), the authors were able to assess acute threshold responses of vegetation to groundwater levels, such as a decline in participation or complete withdrawal. ZDTG thresholds and targets for groundwater-dependent vegetation were evaluated under different classes of conditions and at different rooting depths. The method made it possible to identify areas at risk of drought resulting from groundwater problems throughout the state. The proposed approach provides environmental conservation and restoration specialists with a simple and reliable method for assessing and supporting the water needs of water-dependent ecosystems.
4. regional reef fish assemblage maps provide baseline biogeography for tropicalization monitoring
Walker B.K., Fisco Becker D., Williams G.J. et al.2024. Regional reef fish assemblage maps provide baseline biogeography for tropicalization monitoring. Sci Rep 14, 7893
Anthropogenic increases in global temperatures are facilitating the expansion of tropical species, including coral reef fish, to now subtropical locations. This redistribution of species, known as tropicalization, has serious consequences for economic development, livelihoods, food security, human health and local culture. Measuring the tropicalization of subtropical reef fish assemblages is difficult due to the temporal and spatial variability of species’ ranges and the multitude of factors determining the occurrence and density of assemblages.
This task was undertaken by Florida marine ecologists, analyzing data collected in 2012-2014 in the Kristin Jacobs Coral Reef Conservation Area (Florida Reef – the third largest coral reef in the world). They showed that communities in the southern part of the ocean were characterized by a higher frequency and density of tropical species, while subtropical species dominated in the northern part.
This study contributes to monitoring the tropicalization of southeast Florida’s reef fishes, along the transition between tropical and subtropical ecotones, in order to define regional assemblages of reef fishes and develop new benthic habitat maps to spatially represent their zoogeography. Future tropicalization of reef fishes is expected to result in the homogenization of subtropical and tropical zone assemblages and the expansion of tropical species toward the pole. We also describe this phenomenon in the text on heat stress. The article is another example of an analysis of the problem of changes in the existing ranges of species and remodeling of local resources caused by climate change.
5. Urban Nature Indexes tool offers comprehensive and flexible approach to monitoring urban ecological performance
Pierce J.R., Costadone L., Mannetti L. et al. 2024. Urban Nature Indexes tool offers comprehensive and flexible approach to monitoring urban ecological performance. npj Urban Sustain 4, 22
Cities significantly impact ecosystem integrity and biodiversity, both within and beyond their geographic boundaries. Urban environments consume more than 75 percent of resources, generate 80 percent of greenhouse gases and are largely responsible for some of the major drivers of habitat and biodiversity loss. As rapid urbanization is expected to increase the percentage of the world’s population living in urban areas from 55 percent to more than 68 percent, achieving global biodiversity conservation goals requires the development of tools to mitigate the environmental impact of cities.
Such a comprehensive tool measuring the environmental performance of cities – the Urban Nature Index (UNI) – was proposed by researchers in the pages of the npj journal Urban Sustainability. UNI covers six groups of issues that have measurable impacts on climate change, biodiversity loss, ecosystem services, pollution, consumption, water management and equity. These groups include: consumption-driven factors (e.g., greenhouse gas emissions or water withdrawals), anthropogenic pressures (mainly pollution – air, noise, light or water), habitat condition, species condition, ecosystem services and institutional responses (e.g., legislation, education, governance).
The index was developed by an interdisciplinary team of experts and assessed based on a survey analysis of practitioners from 24 cities of all sizes located around the world. The results of the survey indicate that the developed index is very useful for assessing cities’ ecological footprints and adaptation needs. With institutional support, the IUCN Urban Nature Index offers cities the opportunity to assess and enhance their contribution to a more sustainable and biodiverse future.
