Exaptation and emergence as mechanisms to cross fitness valleys during evolution: an example using simulated homing behaviour

Evolution is often considered a gradual hill climbing process, slowly increasing the fitness of organisms. I investigate the evolution of homing behaviour in simulated intertidal limpets. In order to evolve path integration as a homing mechanism, a temporary reduction in an organism’s fitness is required – since high developmental costs occur before a successful homing strategy evolves. Simple hill-climbing algorithms, therefore, only rarely result in the evolution of a functional homing behaviour. The inclusion of a second behaviour (trail-following) greatly increases the frequency of success of evolution of a path integration strategy. Initially an emergent homing behaviour is formed combining path integration with trail following. This also demonstrates evolution through exaptation, since the original role of trail following is likely to be unrelated to homing. Analysis of the fitness landscapes of homing in the presence of trail-following behaviour shows a high variability of fitness, which results in the formation of ‘stepping-stones’ of high fitness across fitness valleys. By using these stepping-stones, simple hill-climbing algorithms can reach the global maximum fitness value

Efecto de la descarga de aguas residuales sobre la dinámica poblacional de Melarhaphe neritoides (Gastropoda: Littorinidae).

The discharges of sewage effluent treatment plants has a major impact on coastal communities. In our study area (western coast of Portugal) Melarhaphe neritoides (L. 1758) is the dominant high-shore gastropod. Two populations of M. neritoides were studied in order to understand the impact of sewage discharges on intertidal communities: one population in an impacted area and the other in a similar but unimpacted area (reference site). Environmental data and abundance, biomass, population structure and annual growth production of M. neritoides were estimated in the two areas. The results showed that M. neritoides density is higher in the impacted area as a result of massive settlement. The sewage discharge increases the nutrient concentrations in the water, which causes more microalgae to grow on the rocky surfaces. This higher availability of food may promote recruitment. However, we found high mortality in the juveniles in the impacted area, which affected density values on the upper shore levels (where we found the adults) of both areas. Moreover, the adults were bigger in the unimpacted area, which suggests that individuals grow more or live longer in this area.Las descargas de aguas residuales de depuradoras son uno de los mayores impactos sobre las comunidades costeras. En nuestra área de estudio (costa oeste de Portugal) Melarhaphe neritoides (L. 1758) es el gasterópodo dominante en la zona supralitoral. Para entender el impacto que estos vertidos tienen sobre las comunidades intermareales, estudiamos dos poblaciones de M. neritoides: una en un área contaminada y otra en una zona similar, pero no impactada (zona de referencia). En ambas áreas se registraron datos medioambientales, datos de abundancia y biomasa de M. neritoides y se estimó la estructura de las poblaciones y la producción anual. Los resultados muestran una mayor densidad de M. neritoides en la zona contaminada, como resultado de una colonización masiva. Las descargas de aguas residuales aumentan la concentración de nutrientes en el agua, provocando un mayor crecimiento de microalgas en la superficie de las rocas, lo que facilita la colonización. Sin embargo, verificamos una elevada mortalidad de juveniles en la zona contaminada que aproximó los valores de la densidad de las poblaciones en las zonas más altas del litoral (donde encontramos los adultos) en ambas zonas. Además, los adultos eran de mayor tamaño en las áreas no contaminadas, lo que sugiere que en esta zona los individuos tienen un mayor crecimiento o viven durante más tiempo

Science-based restoration monitoring of coastal habitats, Volume Two: Tools for monitoring coastal habitats

Healthy coastal habitats are not only important ecologically; they also support healthy coastal communities and improve the quality of people’s lives. Despite their many benefits and values, coastal habitats have been systematically modified, degraded, and destroyed throughout the United States and its protectorates beginning with European colonization in the 1600’s (Dahl 1990). As a result, many coastal habitats around the United States are in desperate need of restoration. The monitoring of restoration projects, the focus of this document, is necessary to ensure that restoration efforts are successful, to further the science, and to increase the efficiency of future restoration efforts

Accumulation of marine microplastics along a trophic gradient as determined by an Agent-Based Model

Microplastics are ubiquitous in the marine environment and are now consistently found in almost all marine animals. This study examines the rate of accumulation in a modelled filter feeder (mussels) both from direct uptake of microplastics and from direct uptake in addition to trophic uptake (via consuming plankton which have consumed microplastic themselves). We show that trophic uptake plays an important role in increasing plastic present in filter feeders, especially when consumption of the plastic does not reduce its overall abundance in the water column (e.g. in areas with high water flow such as estuaries). However, we also show that trophic transfer increases microplastic uptake, even if the amount of plastic is limited and depleted, as long as plankton are able to reproduce (for example, as would happen during a plankton bloom). If both plankton and plastic are limited and reduced in concentration by filter feeding, then no increase in microplastic by trophic transfer occurs, but microplastic still enters the filter feeders. The results have important implications for large filter feeders such as baleen whales, basking and whale sharks, as these animals concentrate their feeding on zooplankton blooms and as a result are likely to consume more plastic than previous studies have predicted

Cymatium muricinum and other ranellid gastropods: major predators of cultured tridacnid clams

Predators, Predation, Clam culture, Feeding behaviour, Reproduction, Recruitment, Environmental factors Cymatium muricinum, Tridacnidae

Oceanography and Marine Biology

Oceanography and Marine Biology: An Annual Review remains one of the most cited sources in marine science and oceanography. The ever-increasing interest in work in oceanography and marine biology and its relevance to global environmental issues, especially global climate change and its impacts, creates a demand for authoritative refereed reviews summarizing and synthesizing the results of both historical and recent research. This Volume celebrates 60 years of OMBAR, over which time it has been an essential reference for research workers and students in all fields of marine science. The peer-reviewed contributions in Volume 60 are available to read Open Access via this webpage and on OAPEN. If you are interested in submitting a review for consideration for publication in OMBAR, please email the Editor-in-Chief, Stephen Hawkins ([email protected]) for Volume 61. For Volume 62 onwards, please email the new co-Editors in Chief, Dr Peter Todd ([email protected]) and Dr Bayden Russell ([email protected]). Volume 60 features an editorial on the UN Decade of Ocean Science and goes on to consider such diverse topics as Cenozoic tropical marine biodiversity, blue carbon ecosystems in Sri Lanka, marine litter and microplastics in the Western Indian Ocean, and the ecology and conservation status of the family Syngnathidae in southern and western Africa. This volume also contains a retrospective Prologue on the evolution of OMBAR and pays tribute to one of its early Editors in Chief, Margaret Barnes, by providing an update on her review in OMBAR of the stalked barnacle Pollicipes. Supplementary online videos as well as additional Tables and Appendices are available on the Support Tab of the book's Routledge webpage. An international Editorial Board ensures global relevance and expert peer review, with editors from Australia, Canada, Hong Kong, Ireland, Singapore and the UK. The series volumes find a place in the libraries of not only marine laboratories and oceanographic institutes, but also universities worldwide

Oceanography and Marine Biology

Oceanography and Marine Biology: An Annual Review remains one of the most cited sources in marine science and oceanography. The ever-increasing interest in work in oceanography and marine biology and its relevance to global environmental issues, especially global climate change and its impacts, creates a demand for authoritative refereed reviews summarizing and synthesizing the results of both historical and recent research. This Volume celebrates 60 years of OMBAR, over which time it has been an essential reference for research workers and students in all fields of marine science. The peer-reviewed contributions in Volume 60 are available to read Open Access via this webpage and on OAPEN. If you are interested in submitting a review for consideration for publication in OMBAR, please email the Editor-in-Chief, Stephen Hawkins ([email protected]) for Volume 61. For Volume 62 onwards, please email the new co-Editors in Chief, Dr Peter Todd ([email protected]) and Dr Bayden Russell ([email protected]). Volume 60 features an editorial on the UN Decade of Ocean Science and goes on to consider such diverse topics as Cenozoic tropical marine biodiversity, blue carbon ecosystems in Sri Lanka, marine litter and microplastics in the Western Indian Ocean, and the ecology and conservation status of the family Syngnathidae in southern and western Africa. This volume also contains a retrospective Prologue on the evolution of OMBAR and pays tribute to one of its early Editors in Chief, Margaret Barnes, by providing an update on her review in OMBAR of the stalked barnacle Pollicipes. Supplementary online videos as well as additional Tables and Appendices are available on the Support Tab of the book's Routledge webpage. An international Editorial Board ensures global relevance and expert peer review, with editors from Australia, Canada, Hong Kong, Ireland, Singapore and the UK. The series volumes find a place in the libraries of not only marine laboratories and oceanographic institutes, but also universities worldwide

Oyster Reef Habitat Restoration : a synopsis and synthesis of approaches; proceedings from the symposium, Williamsburg, Virginia, April 1995

This volume has its origin in a symposium held in Williamsburg, VA in April 1995, though most of the chapters have been significantly revised in the interim. The primary purpose of the symposium was to bring together state fisheries managers involved in fisheries-directed oyster enhancement and research scientists to refine approaches for enhancing oyster populations and to better develop the rationale for restoring reef habitats. We could hardly have anticipated the degree to which this been successful. In the interim between the symposium and the publication of this volume the notion that oyster reefs are valuable habitats, both for oysters and for the other ecosystem services they provide, has been gaining wider acceptance. . . . Table of Contents Introduction and Overview by Mark W. Luckenbach, Roger Mann and James A. Wesson Part I. Historical Perspectives Chapter 1 - The Evolution of the Chesapeake Oyster Reef System During the Holocene Epoch by William J. Hargis, Jr. Chapter 2 - The Morphology and Physical Oceanography of Unexploited Oyster Reefs in North America by Victor S. Kennedy and Lawrence P. Sanford Chapter 3 - Oyster Bottom: Surface Geomorphology and Twentieth Century Changes in the Maryland Chesapeake Bay by Gary F. Smith, Kelly N. Geenhawk and Dorothy L. Jensen Part II. Synopsis of Ongoing Efforts Chapter 4 - Resource Management Programs for the Eastern Oyster, Crassostrea virginica,in the U.S. Gulf of Mexico ...Past, Present and Future by Richard L. Leard, Ronald Dugas and Mark Benigan Chapter 5 - Oyster Habitat Restoration: A Response to Hurricane Andrew by William S. Perret, Ronald Dugas, John Roussel, Charles A. Wilson, and John Supan Chapter 6 - Oyster Restoration in Alabama by Richard K. Wallace, Kenneth Heck and Mark Van Hoose Chapter 7 - A History of Oyster Reef Restoration in North Carolina by Michael D. Marshall, Jeffrey E. French and Stephen W. Shelton Chapter 8 - Oyster Restoration Efforts in Virginia by James Wesson, Roger Mann and Mark Luckenbach Part Ill. Reef Morphology and Function - Questions of Scale Chapter 9 - South Carolina Intertidal Oyster Reef Studies: Design, Sampling and Focus for Evaluating Habitat Value and Function by Loren D. Coen, David M. Knott, Elizabeth L. Wenner, Nancy H. Hadley, Amy H. Ringwood and M. Yvonne Bobo Chapter 10 - Small-scale Patterns of Recruitment on a Constructed Intertidal Reef: The Role of Spatial Refugia by Ian K. Bartol and Roger Mann Chapter 11 - Perspectives on Induced Settlement and Metamorphosis as a Tool for Oyster Reef Enhancement by Stephen Coon and William K. Fitt Chapter 12 - Processes Controlling Local and Regional Patterns of Invertebrate Colonization: Applications to the Design of Artificial Oyster Habitat by Richard W. Osman and Robert B. Whitlatch Chapter 13 - Reefs as Metapopulatons: Approaches for Restoring and Managing Spatially Fragmented Habitats by Robert B. Whitlatch and Richard W. Osman Chapter 14 - Application of Landscape Ecological Principles to Oyster Reef Habitat Restoration by David B. Eggleston Chapter 15 - Use of Oyster Reefs as a Habitat for Epibenthic Fish and Decapods by Martin H. Posey, Troy D. Alphin, Christopher M. Powell and Edward Townsend Chapter 16 - Are Three Dimensional Structure and Healthy Oyster Populations the Keys to an Ecologically Interesting and Important Fish Community? by Denise L. Breitburg Chapter 17 - Materials Processing by Oysters in Patches: Interactive Roles of Current Speed and Seston Composition by Deborah Harsh and Mark W. Luckenbach Chapter 18 - Oyster Reefs as Components in Estuarine Nutrient Cycling: fucidental or Controlling? by Richard F. Dame Part IV. Alternative Substrates Chapter 19 - Use of Dredged Material for Oyster Habitat Creation in Coastal Virginia by Walter I. Priest, III, Janet Nestlerode and Christopher W. Frye Chapter 20 - Alternatives to Clam and Oyster Shell as Cultch for Eastern Oysters by Haywood, E. L., III, T. M. Soniat and R. C. Broadhurst, III Chapter 21 - Dredged Material as a Substrate for Fisheries Habitat Establishment in Coastal Waters by Douglas Clarke, David Meyer, Allison Veishlow and Michael LaCroix Part V. Management Options and Economic Considerations Chapter 22 - Managing Around Oyster Diseases in Maryland and Maryland Oyster Roundtable Strategies by Kennedy T. Paynter Chapter 23 - Chesapeake Bay Oyster Reefs, Their Importance, Destruction and Guidelines for Restoring Them by William J. Hargis, Jr. and Dexter S. Haven Chapter 24 - Economics of Augmentation of Natural Production Using Remote Setting Techniques by John E. Supan, Charles A. Wilson and Kenneth J. Robert