FRESHWATER NEWS
Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB)
Research for the future of our freshwaters – that is IGB’s guiding principle!
September 2023
Options for tackling decline in pike populations around Rügen ~ Expert knowledge for a day at the lake ~ Better protection of small water bodies ~ Stagnating recovery of biodiversity in river systems ~ Self-purification of rivers on very small spatial scale ~ A natural bacteria-fungi consortium for water treatment ~ Animal welfare in crustacean farming ~ Protection of the night
Hello!
Summer is almost over, as is, for most of us, the holiday season. Some of you may have spent your vacation on #Rügen – not only the #Baltic Sea, but also the Bodden landscape (brackish lagoons) around the island is a popular holiday destination. What many do not know: the #Bodden is also home to one of the largest and fastest-growing populations of #pike, attracting many #anglers from Germany and abroad, as well as commercial fishermen and women and natural predators such as cormorants and grey seals. But pike catches are declining, which is a cause for concern from both an environmental and tourism perspective. In the BODDENHECHT project, IGB scientists set out to find out why. They have now presented their findings, along with clear recommendations for policymakers, authorities and user groups.
Life in bathing lakes
Late summer is also a great time to enjoy our #lakes – as long as the water is not streaked with tiny green dots or stripes that spoil the swim, as experienced over the last few days of hot weather. This could be an indication of #cyanobacteria. Cloudy threads of algae on the shore, however, are a sign of filamentous #algae. We have put together a clear summary of other things that swim, grow and crawl in water, as well as advice on what to avoid:
Small standing waters
Small standing waters may well be less suitable for bathing, but are still important as places for #recreation, relaxation and experiencing nature first-hand. And yet they are more than just collections of water in the landscape; they are diverse #habitats. In fact, they are home to a higher proportion of rare, endemic and threatened freshwater #species than larger lakes or rivers because of the enormous range of habitats they provide. They are found in woodland, agricultural and urban settings. Some hold water all year round or just for a few weeks or months. They can be natural or man-made. But they have one thing in common: they are particularly vulnerable to low rainfall and falling #groundwater levels, and they are increasingly drying out. This endangers the animal and plant species that depend on these water bodies. A new IGB Dossier shows ways in which small standing waters can be better protected, restored or newly created.
Biodiversity in European rivers
#Biodiversity in European rivers has partially recovered – but only between 1968 and 2010, and from an all-time low. This has been found by an international team of researchers using data on invertebrates. The comprehensive study shows that biodiversity in river systems in 22 European countries initially recovered due to improved #water #quality. Since 2010, however, biodiversity improvement has stagnated; many river systems have not fully recovered. The researchers therefore recommend additional measures to stimulate the recovery of biodiversity in inland waters. This is also urgently needed in the face of current and future increasing pressures such as pollution, #sealing, #drought, #warming and the spread of invasive species.?
The river’s “liver”
Staying on the subject of #rivers: the inconspicuous layer in the riverbed where surface and groundwater mix is the hyporheic zone. This is where trace organic compounds can be attenuated – on a very small spatial scale. IGB researchers have now developed a new method to study attenuation performance along a hyporheic flow path in the field. They found that along a flow path of just 35 centimetres, several trace organic compounds were strongly attenuated: the concentrations of #acesulfame (artificial sweetener), #iopromide and #iomeprol (both X-ray contrast media), #metoprolol (beta-blocker) and #gabapentin (anticonvulsant) were at least 75% lower in the hyporheic zone at the end of the flow path than the corresponding concentrations in surface water.?
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Water purification with biotechnology
#Microorganisms are also known to help break down #pollutants and purify water – for example, #nitrogen, which is one of the major pollutants in inland waters and human #wastewater, especially in the form of inorganic #nitrite and #nitrate. Researchers from the Chinese Ministry of Natural Resources in Xiamen and IGB have succeeded in identifying a natural fungus-bacteria consortium that metabolises nitrate particularly efficiently and consistently. This could be crucial for the further development of biotechnological approaches in water treatment. It also highlights the important role of #fungi in aquatic #ecosystems.
More toxic algae in mountain lakes
Taken together, billions of microorganisms such as #algae, #fungi and #bacteria make up what is referred to as the #biofilm – a thin slimy layer that covers stones, plants and the bottom of the lake. Researchers from France’s Institut National Polytechnique de Toulouse, Austria’s University of Natural Resources and Life Sciences (BOKU) and IGB have shown that the microbial biofilm composition is changing as a result of global change, even in remote mountain lakes. It is becoming increasingly toxic: species that indicate good water quality are declining, while cyanotoxin-producing #cyanobacteria are increasing.?
Animal welfare in crustacean farming
#Crustaceans are a popular food. Due to the high demand for crustaceans, they are farmed on a large scale in #aquaculture. This is particularly the case for #shrimp, which has seen production almost double in the last decade. However, too little is known about the sensitivity and stress response of these creatures. Seeking to address this gap, researchers from IGB and the Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung are developing an assessment system for improved animal #welfare and animal health in shrimp #farming within the CrustaWohl project. In an interview, IGB scientist Dr Sven Würtz explains why aquaculture practitioners should address this issue with urgency.
Protection of the night
There is an urgent need to incorporate new knowledge into lighting design to avoid negative impacts on people and the environment, while meeting safety and visibility requirements. (Dr Franz H?lker)
From animal welfare to protection of the #night: acting in close cooperation with IGB, the Federal Agency for Nature Conservation (BfN) has published a new special issue on the subject of #light pollution. The publication provides information on the current state of research, as well as on approaches to systematic #lighting design and legal requirements.
Save the dates
17 October 2023 | Berlin: The Brazilian Academy of Sciences (ABC) and the German National Academy of Sciences Leopoldina are organising a workshop on “Sustainable Aquaculture – Environmental Impacts and Food Security” with the support of IGB. The keynote and roundtable discussion on the topic of “From Aquafarm to Fork? Sustainable Aquaculture as Part of a Resilient Global Food System” are open to the interested public at the Embassy of Brazil.
18 October to 26 June 2024 | Potsdam: The exhibition entitled “City, Country, Climate.”, presented by the Brandenburgische Landeszentrale für politische Bildung (Brandenburg Regional Centre for Political Education), shows how the climate has affected Brandenburg and how it is changing. It is also about climate policy and sustainability: How can we get involved and have a say? And how can we change the way we live and do business? Expert input on the region’s water bodies was provided by IGB.
1 to 10 November 2023 | Berlin: For Berlin Science Week, we make the invisible visible as a single drop of water becomes a cosmos of wonder and discovery in the Microbe Cabinet on Holzmarkt. In collaboration with artist Francisca Rocha Gon?alves and colleagues from the Universityof Aveiro (Portugal), we will shed light on bacteria, algae, fungi and other organisms.
Enjoy the late summer,?
The IGB Team
The next issue of FRESHWATER NEWS will be published in November 2023.