No abstract

Patellid limpets are dominant grazers on intertidal rocky shores of NW Europe with a key role in structuring the eulittoral community. Localised loss of limpets and the subsequent reduction in grazing pressure is known to result in important changes in community structure, through the development of canopy-forming macroalgae, and an associated increase in species diversity and community complexity. The level of determinism in the community level response to localised loss of patellid limpets was assessed at spatial scales from 100s of kilometres to 10s of metres and temporal scales from weeks to months at mid-tide level of exposed rocky shores. Limpets were removed and excluded from experimental plots to simulate localised limpet loss and appropriate controls established. Experimental plots were established in replicate patches at 2 shores at each of 2 regional locations, separated by approximately 500 km: the Isle of Man and SW England. Removals were conducted on 2 dates within each of 2 seasons (summer and winter) and the community level response monitored for a period of 12 mo. There was a clear effect of limpet loss at all spatial and temporal scales, with rapid development of green ephemeral algae followed by a fucoid canopy. However, the degree of determinism in the development of canopy-forming algae differed markedly between the 2 locations. At the northerly location, the Isle of Man, fucoid algae developed quickly and dominated all areas of limpet exclusion; there was little variability between plots. In contrast, in SW England, the abundance of fucoid algae was significantly lower and much more variable. Such geographic changes in the development of macroalgae in the absence of the dominant grazer are discussed in relation to rocky shore community dynamics and the latitudinal change in balance between grazers and algae over the wave exposure gradient.

Electron cryo-microscopy (cryo-EM) has played an increasingly important role in elucidating the structure and function of macromolecular assemblies in near native solution conditions. Typically, however, only non-atomic resolution reconstructions have been obtained for these large complexes, necessitating computational tools for integrating and extracting structural details. With recent advances in cryo-EM, maps at near-atomic resolutions have been achieved for several macromolecular assemblies from which models have been manually constructed. In this work, we describe a new interactive modeling toolkit called Gorgon targeted at intermediate to near-atomic resolution density maps (10-3.5 Å), particularly from cryo-EM. Gorgon's de novo modeling procedure couples sequence-based secondary structure prediction with feature detection and geometric modeling techniques to generate initial protein backbone models. Beyond model building, Gorgon is an extensible interactive visualization platform with a variety of computational tools for annotating a wide variety of 3D volumes. Examples from cryo-EM maps of Rotavirus and Rice Dwarf Virus are used to demonstrate its applicability to modeling protein structure.

No abstract

The sprawl of marine construction is one of the most extreme human modifications to global seascapes. Nevertheless, its global extent remains largely unquantified compared to that on land. We synthesized disparate information from a diversity of sources to provide a global assessment of the extent of existing and projected marine construction and its effects on the seascape. Here we estimated that the physical footprint of built structures was at least 32,000 km 2 worldwide as of 2018, and is expected to cover 39,400 km 2 by 2028. The area of seascape modified around structures was 1.0-3.4 × 10 6 km 2 in 2018 and was projected to increase by 50-70% for power and aquaculture infrastructure, cables and tunnels by 2028. In 2018, marine construction affected 1.5% (0.7-2.4%) of global Exclusive Economic Zones, comparable to the global extent of urban land estimated at 0.02-1.7%. This study provides a critical baseline for tracking future marine human development.

Patellid limpets are very important grazers on NE Atlantic rocky shores, and can occur in clumps or as solitary individuals. When oystercatchers are foraging for Limpets on rocky shores, they are often presented with a choice between solitary and clumped h p e t s . We attempted to establish whether oystercatchers express a preference for limpet prey ltems from these different distributions. Oystercatchers spent far more time foraging in areas of less clumped limpets than in areas of clumped limpets, despite lower prey density. We found a strong preference for sohtary prey items, and increased chances of successful predation of solitary limpets. Possible explanations for this choice are discussed. This preference for attacking solitary 1:impets may have important unpl~cations for rocky shore dynamics by shaping the spatial patterns of limpets. This may then ~nfluence the probability of Fucus germlings escaping limpet grazing.

Human population growth and accelerating coastal development have been the drivers for unprecedented construction of artificial structures along shorelines globally. Construction has been recently amplified by societal responses to reduce flood and erosion risks from rising sea levels and more extreme storms resulting from climate change. Such structures, leading to highly modified shorelines, deliver societal benefits, but they also create significant socioeconomic and environmental challenges. The planning, design and deployment of these coastal structures should aim to provide multiple goals through the application of ecoengineering to shoreline development. Such developments should be designed and built with the overarching objective of reducing negative impacts on nature, using hard, soft and hybrid ecological engineering approaches. The design of ecologically sensitive shorelines should be context-dependent and combine engineering, environmental and socioeconomic considerations. The costs and benefits of ecoengineered shoreline design options should be considered across all three of these disciplinary domains when setting objectives, informing plans for their subsequent maintenance and management and ultimately monitoring and evaluating their success. To date, successful ecoengineered shoreline projects have engaged with multiple stakeholders (e.g. architects, engineers, ecologists, coastal/port managers and the general public) during their conception and construction, but few have evaluated engineering, ecological and socioeconomic outcomes in a comprehensive manner. Increasing global awareness of climate change impacts (increased frequency or magnitude of extreme weather events and sea level rise), coupled with future predictions for coastal development (due to population growth leading to urban development and renewal, land reclamation and establishment of renewable energy infrastructure in the sea) will increase the demand for adaptive techniques to protect coastlines. In this review, we present an overview of current ecoengineered shoreline design options, the drivers and constraints that influence implementation and factors to consider when evaluating the success of such ecologically engineered shorelines.

Defenses against predators may be physiological, morphological, behavioral, or combinations thereof and are nearly always induced, at least in part, by prey perception of predation risk. One antipredation behavior is to group; however the way in which this translates into a reduction in risk to an individual is not fully understood. Here we demonstrate a novel aspect of grouping as a defense, using aggregated limpets (Patella vulgata) as a test system. Although not having experienced the predator directly, potential prey in aggregations detect the vibrations of an attack on a group member and reduce their vulnerability to predation. This effect travels further and lasts longer than would be expected. Our results imply that, for a prey showing a mix of distributions (some solitary and some aggregated), aggregations may probably be easier to find but actually represent a single predation opportunity.