Moritz Mercker

• Dr. rer. nat.
• PostDoc Position at Heidelberg University

Thin elastic surfaces frequently contain molecules influencing their mechanical properties. Such structures occur at different scales in biological systems. Prominent examples are bilayer membranes and cell tissues. We introduce a continuous dynamical model of deformation of lateral inhomogeneous surfaces, using the example of artificial membranes....

Motivated by recent experimental findings, we propose a novel mechanism of embryonic pattern formation based on coupling of tissue curvature with diffusive signaling by a chemical factor. We derive a new mathematical model using energy minimization approach and show that the model generates a variety of morphogen and curvature patterns agreeing wit...

A continuous model of two coupled monolayers constituting a fluid bilayer membrane is presented. The model is based on the minimization of a membrane free energy considering in both monolayer leaflets two different molecule types, undergoing lateral phase separation. Differences in the mechanical properties of the molecules, such as shape, stiffnes...

The bud emergence (BEM)46 proteins are evolutionarily conserved members of the alpha/beta-hydrolase super family, but their exact role remains unknown. To better understand the cellular role of BEM46 and its homologs, we used the model organism Neurospora crassa in conjunction with bem46 RNAi, over-expression vectors, and repeat induced point mutat...

Anthropogenic structures such as overhead powerlines pose potentially high collision risks to flying animals, particularly birds, leading to millions of fatalities each year. Studies of bird collisions with powerlines to date, however, have estimated different numbers of collision per year and per kilometer in highly variable landscapes. This study...

Hydra head regeneration consists of hypostome/organizer and tentacle development, and involves Notch and Wnt/β-catenin signaling. Notch inhibition blocks hypostome/organizer regeneration, but not the appearance of the tentacle tissue. β-Catenin inhibition blocks tentacle, but not hypostome/organizer regeneration. Gene expression analyses during hea...

The spontaneous emergence of tissue patterns is often attributed to biochemical reaction-diffusion systems. In Hydra tissue regeneration, the formation of a Wnt signaling center serves as a well-known example of such a process. However, despite extensive research, a strictly biochemical mechanism for self-organization in Hydra remains elusive. In t...

A differentiated understanding of how regional human activities affect the spatial distribution and numbers of animals within specific areas of interest is of great ecological importance. Estimating these effects from empirical data is challenging however, because human activities can affect animals in qualitatively different ways and on different...

Effective protection of highly mobile and data-poor species constitutes a great challenge amid growing ocean exploitation and use. Blue whales and bowhead whales in the NorthEast Atlantic face several threats, such as climate change, ship strikes, pollution, and entanglement in fishing gear. Consequently, the OSPAR ("Oslo-Paris Convention for the P...

The “hybrid model” developed in the probabilistic pilot study has now been improved and finalized for the red kite in the form of the “Raumnutzungs-Kollisionsrisikomodell” (RKR model). The development of the RKR model was intensively supported by the Probabilistic Subgroup (UAG-2) and a project-accompanying working group (PAG). The RKR model is a...

The Notch-signalling pathway plays an important role in pattern formation in Hydra. Using pharmacological Notch inhibitors (DAPT and SAHM1), it has been demonstrated that HvNotch is required for head regeneration and tentacle patterning in Hydra. HvNotch is also involved in establishing the parent-bud boundary and instructing buds to develop feet a...

Governments are under increasing pressure to reduce greenhouse gas emissions, and large-scale wind farms are being developed in marine environments worldwide. However, top predators are strongly affected by environmental change and anthropogenic activities. Common guillemots (Uria aalge, hereafter guillemots), as one of the world’s most numerous se...

Wnt- and Notch signaling pathways are involved in regulating Hydra head regeneration. The Notch-inhibitor DAPT blocks expression of transcriptional repressor genes including CnGsc and HyHes and attenuates hypostomal HyWnt3- and HyBMP2/4 expression in regenerating Hydra heads while increasing expression of HyBMP5/8b and the c-fos-related gene HyKaya...

The Notch-signalling pathway plays an important role in pattern formation in Hydra . Using pharmacological Notch inhibitors (DAPT and SAHM1), it has been demonstrated that HvNotch is required for head regeneration and tentacle patterning in Hydra . HvNotch is also involved in establishing the parent-bud boundary and instructing buds to develop feet...

Frequency-domain electromagnetic induction (FDEMI) methods are frequently used in non-invasive, area-wise mapping of the subsurface electromagnetic soil properties. A crucial part of data analysis is the geophysical inversion of the data, resulting in either conductivity and/or magnetic susceptibility subsurface distributions. We present a novel 1D...

The main goal of the LIFE EUROKITE project is to reduce anthropogenic causes of mortality of the red kite in Europe. The efficient protection of the red kite requires the detailed understanding of overall mortality reasons, especially focusing on those caused by legal and illegal human activities. The LIFE EUROKITE project focuses on a Europe-wide...

Coastal, and to a lesser extend inland wetlands, are critical habitats for wintering shorebirds. Given the significant population declines of most shorebird species worldwide, the current degradation of coastal habitats through climate change and human activities raises severe conservation concerns. In order to ensure sufficient and adequate habita...

EU member countries and the UK are currently installing numerous offshore windfarms (OWFs) in the Baltic and North Seas to achieve decarbonization of their energy systems. OWFs may have adverse effects on birds; however, estimates of collision risks and barrier effects for migratory species are notably lacking, but are essential to inform marine sp...

A current overview of breeding populations of seabirds and coastal birds is presented for the North Sea island of Helgoland, 50 km off the German coast. Dramatic changes have taken place over the past 15-20 years, including both large increases (Common Eider, Herring Gull, Common Guillemot, Razorbill, Northern Gannet) and large decreases (Oystercat...

The North Sea is a key area worldwide for the installation of offshore wind farms (OWFs). We analysed data from multiple sources to quantify the effects of OWFs on seabirds from the family Gaviidae (loons) in the German North Sea. The distribution and abundance of loons changed substantially from the period before to the period after OWF constructi...

Nematocysts are generated by secretion of proteins into a post-Golgi compartment. They consist of a capsule that elongates into a long tube, which is coiled inside the capsule matrix and expelled during its nano-second discharge deployed for prey capture. The driving force for discharge is an extreme osmotic pressure of 150 bar. The complex process...

Installation of offshore wind farms (OWFs) is becoming increasingly important to ensure a reduction in greenhouse gas emissions; however, OWFs also pose a threat to migrating birds and other wildlife. Informed marine spatial planning is therefore crucial, but individual‐based high‐resolution data on bird migration across the sea are currently lacki...

Hydra ’s almost unlimited regenerative potential is based on Wnt signaling, but so far it is unknown how the injury stimulus is transmitted to discrete patterning fates in head and foot regenerates. We previously identified mitogen-activated protein kinases (MAPKs) among the earliest injury response molecules in Hydra head regeneration. Here, we sh...

Migration patterns in birds vary in space and time. Spatial patterns include chain, leapfrog and telescopic migration. Temporal patterns such as migration duration, number, and duration of stopovers may vary according to breeding latitude, sex, and season. This study aimed to verify these patterns in a long‐distance migrant, the Eurasian curlew Num...

Fungi show a high degree of morphological convergence. Regarded for a long time as an obstacle for phylogenetic studies, homoplasy has also been proposed as a source of information about underlying morphogenetic patterning mechanisms. The "local-activation and long-range inhibition principle" (LALIP), underlying the famous reaction-diffusion model...

Monitoring of grassland (both permanent, i.e., more than five years and, temporary typologies) is relevant for the ecosystem perspective and for agricultural sustainability. Assessing the spatial and areal extent of grassland at country and sub-country level, is relevant for a number of ecosystem services, agri-environmental indicators and EU polic...

During early kidney organogenesis, nephron progenitor (NP) cells move from the tip to the corner region of the ureteric bud (UB) branches in order to form the pretubular aggregate, the early structure giving rise to nephron formation. NP cells derive from metanephric mesenchymal cells and physically interact with them during the movement. Chemotaxi...

The continuing global expansion of electricity networks increases the risk of bird collisions with power lines. Several field studies have demonstrated that this risk can be reduced by marking lines with flight diverters. A before‐after control‐impact (BACI) design is currently the suggested approach for evaluating the effectiveness of these divert...

Turing patterns are commonly understood as specific instabilities of a spatially homogeneous steady state, resulting from activator–inhibitor interaction destabilized by diffusion. We argue that this view is restrictive and its agreement with biological observations is problematic. We present two alternatives to the classical Turing analysis of pat...

We present an integrative statistical approach for estimating the current conditions of marine-bird habitats affected by human activities. We first estimated the influence of multiple human offshore activities on the species of interest using integrative regression techniques. We then used these models to predict the distribution and abundance of t...

Germany is an EU member state and is thus obliged to monitor and protect its marine and coastal areas in the context of international treaties (e.g. EU Marine Strategy Framework Directive, EU Natura2000 directives, Trilateral Monitoring and Assessment Programme, OSPAR) to achieve the good environmental status (GES). Suitable indicators thus need to...

The antagonising interplay between canonical Wnt signalling and Dickkopf (Dkk) molecules has been identified in various processes involved in tissue organisation, such as stem cell differentiation and body-axis formation. Disruption of the interplay between these molecules is related to several diseases in humans. However, the detailed molecular me...

Estimation of bird and bat fatalities due to collision with anthropogenic structures (such as power lines or wind turbines) is an important ecological issue. However, searching for collision victims usually only detects a proportion of the true number of collided individuals. Various mortality estimators have previously been proposed to correct for...

Background The Hydra head organizer acts as a signaling center that initiates and maintains the primary body axis in steady state polyps and during budding or regeneration. Wnt/beta-Catenin signaling functions as a primary cue controlling this process, but how Wnt ligand activity is locally restricted at the protein level is poorly understood. Here...

Background New wildlife telemetry and tracking technologies have become available in the last decade, leading to a large increase in the volume and resolution of animal tracking data. These technical developments have been accompanied by various statistical tools aimed at analysing the data obtained by these methods. Methods We used simulated habi...

Background: Departure decisions in long-distance migratory bird species may depend on favourable weather conditions and beneficial resources at the destination location, overarched by genetic triggers. However, few studies have tried to validate the significance of these three concepts simultaneously, and long-term, high-resolution tagging dataset...

Turing patterns are commonly understood as specific instabilities of a spatially homogeneous steady state, resulting from activator-inhibitor interaction destabilised by diffusion. We argue that this view is restrictive and its agreement with biological observations is problematic. We present two alternative to the 'classical' Turing analysis of pa...

Generating trend and population estimates from bird count data is challenging and a variety of factors have to be taken into account. We present an integrative statistical approach for estimating population numbers and trends for seabirds at sea. The method allows for the integration of bird‐count data from different sources and sampling schemes: o...

Formation of the body axes and the subsequent formation of the apical termini are two fundamental steps during animal development. In Hydra, nuclear β-Catenin and canonical HyWnt3 were identified as major players active in both processes. Based on molecular knowledge of canonical Wnt signaling directly linking nuclear Beta-Catenin and HyWnt3 activi...

Northern gannets (Morus bassanus) have been ranked as one of the most vulnerable species in terms of collision with offshore wind farm (OWF) turbines, and strong avoidance of OWFs has been documented for this species. Gannets increasingly encounter OWFs within the ranges of their largest breeding colonies along the European coasts. However, informa...

Oral presentation abstract

Background: Departure decisions in long-distance migratory bird species may depend on favourable weather conditions and beneficial resources at the destination location, overarched by genetic triggers. However, few studies have tried to validate the significance of these three concepts simultaneously, and long-term, high-resolution tagging datasets...

Background: Choosing the appropriate time to depart for spring migration is crucial to achieving a successful subsequent breeding season among migratory bird species. We expected Eurasian Curlews (Numenius arquata) to start their migration during favourable weather conditions and to adjust their flight heights to prevailing wind conditions. Methods...

The increasing development of offshore wind farms (OWFs) worldwide leads to possible conflicts with the ecological requirements of top predators that largely depend on offshore areas. Seabird species exhibit different behavioural reactions to OWFs, ranging from avoidance resulting in habitat loss, to attraction causing an increased risk of collidin...

Grey seals have become an important part of the ecosystem in the southern North Sea over the last 50 years. However, little is knownabout their spatial utilization of the German North Sea, especially in relation to the dispersal and behaviour of grey seal pups after weaning.We investigated these little-known aspects by recording the movements of 11...

The Hydra head organizer acts as a signaling center that initiates and maintains the primary body axis in steady state polyps and during budding or regeneration. Wnt/beta-Catenin signaling functions as a primary cue controlling this process, but how Wnt ligand activity is locally restricted at the protein level is poorly understood. Here we report...

Seabirds have increasingly encountered offshore wind farms (OWFs) in European waters in the past 10 years, resulting in potential conflicts with offshore foraging areas. During the breeding season, seabirds are restricted in their choice of foraging habitat and are under increased pressure to find enough prey to raise their offspring. However, info...

Estimating population density as precise as possible is a key premise for managing wild animal species. This can be a challenging task if the species in question is elusive or, due to high quantities, hard to count. We present a new, mathematically derived estimator for population size, where the estimation is based solely on the frequency of genet...

Biological membranes define a mechanical boundary of cells and of substructures inside cells. They provide environments specialized for certain chemical or mechanical processes, and are involved in various healthy and pathogenic cellular activities.

The recent COVID-19 pandemic is of big and world-wide concern. There is an intense discussion and uncertainty which factors and sanctions can reduce infection rates. The overall aim is to prevent an overload of the medical system. Even within one country, there is frequently a strong local variability in both -- political sanctions as well as other...

Kaufung Forest and Teutoburg Forest rank among the North German low mountain region; they have been exposed to air pollution for decades. Nevertheless, just the Kaufung Forest has been mentioned as an extreme acidification landscape since the first review on water acidification in Germany. In the meantime, research on acidic depositions, on soil an...

Background: New wildlife telemetry and tracking technologies have become available in the last decade, leading to a large increase in the volume and resolution of animal tracking data. These technical developments have been accompanied by various statistical tools aimed at analysing the data obtained by these methods. Methods: We used simulated ha...

During early kidney organogenesis, nephron progenitor (NP) cells move from the tip to the corner region of the ureteric bud (UB) branches in order to form the pretubular aggregate, the early structure giving rise to nephron formation. Chemotaxis and cell-cell adhesion differences are believed to drive cell patterning during this critical period of...

During early kidney organogenesis, nephron progenitor (NP) cells move from the tip to the corner region of the ureteric bud (UB) branches in order to form the pretubular aggregate, the early structure giving rise to nephron formation. Chemotaxis and cell-cell adhesion differences are believed to drive cell patterning during this critical period of...

About 10 to 12 million birds per year use the intertidal flats of the Wadden Sea in north-eastern Europe as a food source during their moulting, wintering or breeding season and as a stop-over site along the East Atlantic Flyway. The tidal flats are inhabited by a highly productive benthic fauna representing an important link between the marine mic...

comparison of different offshore survey methods for Common Scoters

Precise knowledge of population size and trends is prerequisite for assessing the status of seabird species and taking appropriate conservation measures. Divers (Gavia spec.) are of high conservation concern and reach their peak abundance in the German North Sea during spring migration. Based on generalized additive (mixed) model (GA[M]M) modelling...

Seabirds select suitable habitats at sea, but these habitats may be strongly impacted by marine spatial planning, including the construction of offshore wind farms (OWFs) and the associated ship traffic. Loons (Gavia spp.) are particularly vulnerable to anthropogenic activities and are also of high conservation status, making them particularly rele...

To evaluate the efficiency of bird markers on ground wires a study was started in the Federal State of Schleswig-Holstein in a very bird rich area at the lower Elbe. The investigations embraced the search of carcasses as well as the counting of crossing birds over a period of two years. In several sections of the power line black and white bird def...

Marine ecosystems are exposed to increasing human pressures and climatic change worldwide. It has therefore become essential to describe ecosystem statuses with respect to multinational protection schemes, often necessitating long-term monitoring programmes. Changes in the food-web structure, which can be monitored via stable isotope measurements,...

Chemical and mechanical pattern formation is fundamental during embryogenesis and tissue development. Yet, the underlying molecular and cellular mechanisms are still elusive in many cases. Most current theories assume that tissue development is driven by chemical processes: either as a sequence of chemical patterns each depending on the previous on...

PDF document comprising additional information (text and figures) with respect to structural mechanics and notation, structural model equations, implementation of growth, full mechanochemical model equations, derivation of mechanical invariants as well as robustness of pattern formation. (PDF)

To evaluate the efficiency of bird markers on ground wires a study was started in the Federal State of Schleswig-Holstein in a very bird rich area at the lower Elbe. The investigations embraced the search of carcasses as well as the counting of crossing birds over a period of two years. In several sections of the power line black and white bird def...

Background During embryogenesis, chemical (morphogen) and mechanical patterns develop within tissues in a self-organized way. More than 60 years ago, Turing proposed his famous reaction-diffusion model for such processes, assuming chemical interactions as the main driving force in tissue patterning. However, experimental identification of correspon...

Tissue morphogenesis comprises the self-organized creation of various patterns and shapes. Although detailed underlying mechanisms are still elusive in many cases, an increasing amount of experimental data suggests that chemical morphogen and mechanical processes are strongly coupled. Here, we develop and test a minimal model of the axis-defining s...

Membrane budding is essential for processes such as protein sorting and transport. Recent experimental results with ESCRT proteins reveal a novel budding mechanism, with proteins emerging in bud necks but separated from the entire bud surface. Using an elastic model, we show that ESCRT protein shapes are sufficient to spontaneously create experimen...

Trischen is situated off the coast of Dithmarschen in the German Bight. The island has one of the longest track-records of breeding bird observations, spanning the past 100 years. In this publication we focus on recent developments since the turn of the century and discuss all major aspects concerning island ecology such as climate, geomorphology,...

Mercker, M. & J. Baer 2013: Predator-prey interactions as possible explanation for recent declines of seabird breeding populations – the example of the Wadden Sea island Trischen. Vogelwelt 134: 115 – 127. Trischen Island is located between the estuaries of river Eider and Elbe in the German Bight. The island is part of the Wadden Sea National Park...

Thin, elastic surfaces are a fundamental building block in each biological system. Their main representative on the small scale are biomembranes; an important example on the larger scale are cell tissues. In both cases, the surfaces define a mechanical and chemical border, indispensable for the genesis and maintenance of each organism. An essential...

Thin elastic surfaces containing molecules infuencing the mechanical prop- erties of the surface itself are wide spreaded structures of different scales in biological systems. Prominent examples are bilayer membranes and cell tis- sues. In this paper we present a continuous dynamical model of deforming lateral inhomogeneous surfaces, using the exam...