Diverse macrovegetation can provide heterogeneous habitats for benthic diatoms. Researchers from the CER Institute of Aquatic Ecology and the University of Debrecen, together with specialists from the Middle-Tisza Water Authority studied the importance of microhabitat heterogeneity (emergent, submerged and floating macrophytes) in maintaining diverse periphytic diatom assemblages. Their results were published in the journal Hydrobiologia.

Human well-being and good quality of life are based on the biodiversity of ecosystems and there is an increasing demand to reduce the knowledge gap on the variety of life on Earth. At the same time, an “invisible tragedy” is taking place in freshwater habitats that are highly threatened by the loss of diversity with species disappearing, threatening the functioning of the ecosystem. While relatively more information is available on the processes occurring in plant, animal or microbial communities that are important to human communities, much less is known about the vulnerability and exposure of other groups, including microalgae, which play a key role in ecosystem services. The situation is further complicated by the fact that there is a delicate balance between protecting and “exploiting” multipurpose freshwaters that take a lead in the daily life of human communities. While good ecological condition is essential for the maintenance of diverse communities, water management works such as water level regulation, thinning of macrophyte communities or sediment dredging are important for human recreation in these multipurpose lakes and reservoirs.

This is no different in the largest artificial, multipurpose shallow reservoir of the Carpathian basin, Lake Tisza, which is a UNESCO World Heritage Site. As in other lakes, the composition and biomass of the macrophyte communities form a complex system with benthic and metaphytic microflora assemblages. However, the extensive macrophyte vegetation needs to be thinned at least once a year. In the study, researchers highlighted that the macrovegetation belonging to different life form types, i.e. emergent, submerged and floating, contributes to the taxonomic and trait diversity of the microflora in a different but equally important way. Almost one-third of the benthic diatoms occurred on only one type of aquatic plant, pointing to the unique microhabitat that these macrophytes can provide for microalgae. Besides the microhabitats, however, the regular water level control of the lake also affected the biodiversity of the microalgae, promoting the spread of diatoms between the basins.

These results highlighted that the protection and maintenance of benthic microalgae biodiversity in multipurpose lakes requires delicate water management planning and implementation, but at the same time it is unavoidable for the functioning of a healthy ecosystem.

An international team of researchers has developed a new theoretical framework that bridges physics and biology to provide a unified approach for understanding how evolution and complexity emerge in nature. This new work on “Assembly Theory,” was published on October 4th in Nature.

As Dániel Czégel, the co-first author of the paper from Arizona State University and the Institute of Evolution at the Centre for Ecological Research in Budapest explained, “we have a language for physics, a language for chemistry, and a language for biology and evolution, but they are almost mutually incomprehensible, like as if we were at the early days of Babel. This makes the transition between them very difficult to study. We need something like a lingua franca of medieval port towns, to bridge cultures and languages. But these lingua francas often turn to fully developed languages, separate from their ancestors. Assembly theory is neither physics or chemistry or biology but a mathematical language to talk about historically contingent systems, systems where the existence of current forms are strongly determined by what existed in the past, like the products of biological or technological evolution. It turns out that a coordinate system for such complex objects are nothing like a coordinate system in physics, but it’s more like a space determined by combinatorics and recursivity. The most peculiar thing is that an object is not a point but a series of causes and effects, like a story of the origin of the object. And it’s not even the “real” history, but a fictional one, like an origin myth, but it’s mathematically well-defined within the assembly universe. It’s a counterfactual causal history. But then when we treat objects as their own fictional origin story, we can start to talk about the entangled web of stories of all objects and measure things like the amount of selection and historical contingency that caused those objects to exist. It’s a bit like the particle-wave duality of quantum physics, but for complex objects: sometimes it’s better to think of them as three dimensional structures, sometimes as interrelated construction histories. We have to speak the language of this coordinate system if we assume that life that we’d like to make in the lab or life elsewhere in the universe are not like ours, chemically.”