Alfred Burian

• PhD
• Helmholtz Center for Environmental Research (UFZ)

Saline lakes are hypersensitive to changes in their water balance and therefore show amplified responses to climatic and land-use changes in their catchment. However, despite the resulting, often dramatic ecological consequences, saline lakes rank low on policy agendas as they are assumed to support few ecosystem services and low levels of biodiver...

Intensive agriculture with high reliance on pesticides and fertilizers constitutes a major strategy for ‘feeding the world’. However, such conventional intensification is linked to diminishing returns and can result in ‘intensification traps’—production declines triggered by the negative feedback of biodiversity loss at high input levels. Here we d...

Ratios between viruses, heterotrophic prokaryotes and chlorophyll a are key indicators of microbial food structure and both virus–prokaryote and prokaryote–chlorophyll ratios have been proposed to decrease with system productivity. However, the mechanisms underlying these responses are still insufficiently resolved and their consistency across aqua...

Locomotion in benthic invertebrates can strongly affect habitat selection and ecosystem nutrient cycling. In the case of freshwater mussels, the drivers of locomotion are largely unresolved. Our aim was to assess the influence of light presence and intensity on the locomotory behaviour of freshwater mussels in controlled laboratory experiments. The...

1. Cost‐effective strategies to increase biodiversity are a fundamental requirement to reconcile conservation and food production in agricultural landscapes. Key for the implementation of such strategies is an accurate quantification of both their benefits and potential associated trade‐offs. 2. We therefore assessed, in a commercially managed gras...

The coastline of Sub-Saharan Africa hosts highly diverse fish communities of great conservation value, which are also key resources for local livelihoods. However, many costal ecosystems are threatened by overexploitation and their conservation state is frequently unknown due to their vast spatial extent and limited monitoring budgets. Here, we eva...

Intensive agriculture with high reliance on pesticides and fertilizers constitutes a major strategy for ‘feeding the world’. However, such conventional intensification is linked to diminishing returns and can result in ‘intensification traps’ – production declines triggered by the negative feedback of biodiversity loss at high input levels. We deve...

The exponential growth of herbicide-resistant weeds poses enormous challenges to the sustainability of food systems. While great efforts in weed management are being performed at the plot level, the influence of the landscape context on the presence of herbicide-resistant weeds remains largely unknown. We tested these ideas through a large-scale sa...

Conventional agriculture is frequently associated with large-scale environmental degradation and landscape homogenization. In contrast, ecological intensification incorporates natural habitat conservation and landscape complexity to improve important ecosystem services such as pollination and crop yields. In an observational study of 105 fields in...

A fundamental challenge of land use management is to sustain the production of food, energy and fiber whilst preserving biodiversity and ecosystem functions. Some promising solutions to current resource-use conflicts are rooted in (agro) ecological intensification, which proposes that ecosystem functions provided by natural habitat can largely repl...

The coastline of Sub-Saharan Africa hosts highly diverse fish communities of high conservation value, which are also key resources for local livelihoods. However, many costal ecosystems are threatened by overexploitation and their conservation state is frequently unknown due to limited monitoring budgets and challenges associated with their vast sp...

New methods are required for biomonitoring of poorly known tropical ecosystems, but biological assessments of environmental status are limited by insufficient information on taxonomy, composition and ecology of local communities. The current work applies DNA‐based assessment to establish the impact of various types of anthropogenic disturbances on...

Protozoan predators form an essential component of activated sludge communities that is tightly linked to wastewater treatment efficiency. Nonetheless, very little is known how protozoan predation is channelled via bacterial communities to affect ecosystem functioning. Therefore, we experimentally manipulated protozoan predation pressure in activat...

Background Marine holobionts depend on microbial members for health and nutrient cycling. This is particularly evident in cnidarian-algae symbioses that facilitate energy and nutrient acquisition. However, this partnership is highly sensitive to environmental change—including eutrophication—that causes dysbiosis and contributes to global coral reef...

Global declines in biodiversity highlight the need to effectively monitor density and distribution of threatened species. In recent years, molecular survey methods detecting DNA released by target-species into their environment (eDNA) have been rapidly on the rise. Despite providing new, cost-effective tools for conservation, eDNA-based methods are...

Molecular-based monitoring relying on environmental DNA (eDNA) detection became routinely used around the world in the last few years, especially in aquatic environments. The large potential and increasing applications of this technique calls for technical improvements to optimize the reliability of these surveys. An important technical aspect in t...

‘One World – One Health’ is a developing concept which aims to explicitly incorporate linkages between the environment and human society into wildlife and human health care. Past work in the field has concentrated on aspects of disease, particularly emerging zoonoses, and focused on terrestrial systems. Here, we argue that marine environments are c...

In recent years, eDNA-based assessments have evolved as valuable tools for research and conservation. Most eDNA-based applications rely on comparisons across time or space. However, temporal, and spatial dynamics of eDNA concentrations are shaped by various drivers that can affect the reliability of such comparative approaches. Here, we assessed (i...

Background: Marine holobionts depend on microbial partners for health and nutrient cycling. This is particularly evident amongst cnidarian-Symbiodiniaceae symbioses, where nutrient acquisition is facilitated. However, the symbiosis is sensitive to environmental change - including eutrophication – that cause dysbiosis and host mortality, which contr...

eDNA-based methods represent non-invasive and cost-effective approaches for species monitoring and their application as a conservation tool has rapidly increased within the last decade. Currently, they are primarily used to determine the presence/absence of invasive, endangered or commercially important species, but they also hold potential to cont...

Compound-specific isotope analyses (CSIA) of fatty acids (FA) constitute a promising tool for tracing energy flows in food-webs. However, past applications of FA-specific carbon isotope analyses have been restricted to a relatively coarse food-source separation and mainly quantified dietary contributions from different habitats. Our aim was to eval...

‘One World – One Health’ is a developing concept which aims to explicitly incorporate linkages between the environment and human society in order to facilitate optimising aspects of health. Historically, work has concentrated on aspects of disease, in particular on emerging zoonoses, with a focus on terrestrial systems. Here we argue that the marin...

Abandoned, lost or discarded fishing nets, (ghost nets) represent a major threat to marine vertebrates. However, thorough assessments of their impact on threatened species are largely missing. In the Maldives, olive ridley sea turtles (Lepidochelys olivacea) are frequently caught in ghost nets however the archipelago does not support a significant...

Food quantity–quality interactions determine growth rates and reproductive success of consumers and thereby regulate community dynamics and food web structure. Predator–prey models that shape our conceptual understanding of foraging ecology typically rely on the parametrization of fixed consumer responses to either food quantity or food quality. In...

Background: Coral reefs face unprecedented declines in diversity and cover, a development largely attributed to climate change-induced bleaching and subsequent disease outbreaks. Coral-associated microbiomes may strongly influence the fitness of their hosts and alter heat tolerance and disease susceptibility of coral colonies. Here, we describe a...

Humans have fundamentally altered the cycling of multiple elements on a global scale. These changes impact the structure and function of terrestrial and aquatic ecosystems, with many implications for human health. Most prior studies linking biogeochemical changes to human health have evaluated the effects of single elements in isolation. However, t...

eDNA-based methods represent non-invasive and cost-effective approaches for species monitoring and their application as a conservation tool has rapidly increased within the last decade. Currently, they are primarily used to determine the presence/absence of invasive, endangered or commercially important species, but they also hold potential to cont...

Dikerogammarus haemobaphes is a freshwater gammarid crustacean native to the Ponto-Caspian region. However, the species is rapidly spreading throughout Western Europe and is classed as a highly invasive species. Here we present a novel eDNA assay aimed at detecting D. haemobaphes and demonstrate its suitability with validation steps conducted in-si...

Environmental DNA (eDNA) barcoding has a high potential to increase the cost-efficiency of species detection and monitoring in aquatic habitats. However, despite vast developments in the field, many published assays often lack detailed validation and there is little to no commonly (agreed upon) standardization of protocols. In this study, we evalua...

The freshwater gammarid, Crangonyx floridanus, originates from North America but has invaded and subsequently spread rapidly throughout Japan. We provide here the first genetic and microscopic evidence that C. floridanus has now also reached the United Kingdom. We found this species in two locations separated by more than 200 km (Lake Windermere in...

Human population growth is considered together with climate warming as major driver of change in Sub-Saharan Africa. Research on the implications of increased population densities often utilises community knowledge but without incorporating the view of local stakeholders. In this study, we applied a community-centred approach to assess direct and i...

The freshwater gammarid, Crangonyx floridanus, originates from North America but has invaded and subsequently spread rapidly throughout Japan. We provide here the first genetic and microscopic evidence that C. floridanus has now also reached the United Kingdom. We found this species in two locations separated by more than 200 km (Lake Windermere in...

The flexible regulation of feeding behaviour and nutrient metabolism is a prerequisite for consumers to grow and survive under variable food conditions. Thus, it is essential to understand the ecological trade‐offs that restrict regulatory mechanisms in consumers to evaluate the consequences of nutrient limitations for trophic interactions. Here, w...

A recent study concluded that omnivorous plankton will shift from predatory to herbivorous feeding with climate warming, as consumers require increased carbon:phosphorous in their food. Although this is an appealing hypothesis, we suggest the conclusion is unfounded, based on the data presented, which seem in places questionable and poorly interpre...

East African soda lakes are extreme environments that force organisms to cope with high salinities, pH levels and turbidity, but are nonetheless amongst the most productive ecosystems worldwide. We provide an overview of the species inventory in these lakes, which, amongst other fascinating species, host the well-known cyanoprokaryote Arthrospira f...

Zooplankton blooms are a frequent phenomenon in tropical systems. However, drivers of bloom formation and the contribution of emerging resting eggs are largely unexplored. We investigated the dynamics and the triggers of rotifer blooms in African soda-lakes and assessed their impact on other trophic levels. A meta-analysis of rotifer peak densities...

Soda lakes are simple in biodiversity, but due to their highly stochastic environmental dynamics unexpected shifts in species composition do occur. We studied key drivers for structuring phytoplankton communities and identified variables significantly influencing changes of Arthrospira fusiformis abundance in the Kenyan soda lakes, Nakuru and Bogor...

β-N-Methylamino-L-alanine (BMAA), a neurotoxin reportedly produced by cyanobacteria, diatoms and dinoflagellates, is proposed to be linked to the development of neurological diseases. BMAA has been found in aquatic and terrestrial ecosystems worldwide, both in its phytoplankton producers and in several invertebrate and vertebrate organisms that bio...

Aquatic ecosystems experience large natural variation in elemental composition of carbon (C), nitrogen (N) and phosphorus (P), which is further enhanced by human activities. Primary producers typically reflect the nutrient ratios of their resource, whose stoichiometric composition can vary widely in conformity to environmental conditions. In contra...

1. The analysis of functional groups with a resolution to the individual species level is a basic requirement to better understand complex interactions in aquatic food webs. Species-specific stable isotope analyses are currently applied to analyse the trophic role of large zooplankton or fish species, but technical constraints complicate their appl...

The filamentous spirally coiled cyanoprokaryote Arthrospira fusiformis is found in extremely high densities in tropical soda lakes acting as driving force of the food web. We studied pronounced temporal morphological changes of Arthrospira in Kenyan soda lakes, Nakuru and Bogoria, and identified underlying key factors. Cell (diameter and height) an...

We investigated the feeding behaviour of the dominant microzooplankton of saline lakes in the East African Rift Valley. A set of grazing experiments revealed high ingestion rates of the two euryhaline rotifers Brachionus dimidiatus and Brachionus plicatilis and of the large-sized omnivorous ciliates Frontonia sp. and Condylostoma magnum reflecting...