Effects of Trawling and Dredging on Seafloor Habitat
Effects of Trawling and Dredging on Seafloor Habitat

Author: National Research Council

Publisher: National Academies Press

Published: 2002-08-09

Total Pages: 137

ISBN-13: 0309083400

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Concerns over the potential ecological effects of fishing have increased with the expansion of fisheries throughout the marine waters of the United States. Effects of Trawling and Dredging on Seafloor Habitat describes how assessment of fishing impacts depends on gear type, number and location of bottom tows, and the physical and biological characteristics of seafloor habitats. Many experimental studies have documented acute, gear-specific effects of trawling and dredging on various types of habitat. These studies indicate that low mobility, long-lived species are more vulnerable to towed fishing gear than short-lived species in areas where the seabed is often disturbed by natural phenomena. Trawling and dredging may also change the composition and productivity of fish communities dependent on seafloor habitats for food and refuge. The scale of these impacts depends on the level of fishing effort. This volume presents color maps of fishing effort for all regions with significant bottom trawl or dredge fisheries-the first time that such data has been assembled and analyzed for the entire nation.

Sandy Beach Morphodynamics
Sandy Beach Morphodynamics

Author: Derek Jackson

Publisher: Elsevier

Published: 2020-05-20

Total Pages: 814

ISBN-13: 0081029276

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Sandy beaches represent some of the most dynamic environments on Earth and examining their morphodynamic behaviour over different temporal and spatial scales is challenging, relying on multidisciplinary approaches and techniques. Sandy Beach Morphodynamics brings together the latest research on beach systems and their morphodynamics and the ways in which they are studied in 29 chapters that review the full spectrum of beach morphodynamics. The chapters are written by leading experts in the field and provide introductory level understanding of physical processes and resulting landforms, along with more advanced discussions.

Marine Policy and Economics
Marine Policy and Economics

Author:

Publisher: Elsevier

Published: 2010-10-25

Total Pages: 629

ISBN-13: 0123785588

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Elements of Physical Oceanography is a derivative of the Encyclopedia of Ocean Sciences, Second Edition and serves as an important reference on current physical oceanography knowledge and expertise in one convenient and accessible source. Its selection of articles—all written by experts in their field—focuses on ocean physics, air-sea transfers, waves, mixing, ice, and the processes of transfer of properties such as heat, salinity, momentum and dissolved gases, within and into the ocean. Elements of Physical Oceanography serves as an ideal reference for topical research. References related articles in physical oceanography to facilitate further research Richly illustrated with figures and tables that aid in understanding key concepts Includes an introductory overview and then explores each topic in detail, making it useful to experts and graduate-level researchers Topical arrangement makes it the perfect desk reference

Sand and Sustainability
Sand and Sustainability

Author: Programme des Nations Unies pour l'environnement. GRID-Geneva

Publisher:

Published: 2019

Total Pages: 35

ISBN-13: 9789280737516

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Sand and gravels are the unrecognised foundational material of our economies. They are mined the world over, with aggregates accounting for the largest volume of solid material extracted globally (Peduzzi, 2014; Beiser, 2018). At the same time, these materials cannot be produced from our terrestrial, riverine and marine environments in quantities needed to meet demand from a world of 10 billion people without effective policy, planning, regulation and management. Such actions remain largely unaddressed by decision makers in public or private sectors. It is time to challenge the paradigm of infinite sand resources through constructive dialogue and solution-finding. This report aims to be the starting point from which a productive global conversation on sand extraction can begin. This synthesis was produced following a United Nations Environment Programme expert roundtable event held on 11 October 2018 in Geneva, Switzerland. The discussions emphasised potential solutions for mitigating mineral sands and aggregates extraction impacts and generating adequate support for responsible consumption pathways. Expert views were collated and complemented with additional research and consultation to distil key messages on an agenda for tackling this issue in 2019 and beyond.

Encyclopedia of Ocean Sciences
Encyclopedia of Ocean Sciences

Author:

Publisher: Academic Press

Published: 2019-04-12

Total Pages: 4318

ISBN-13: 0128130822

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The oceans cover 70% of the Earth’s surface, and are critical components of Earth’s climate system. This new edition of Encyclopedia of Ocean Sciences, Six Volume Set summarizes the breadth of knowledge about them, providing revised, up to date entries as well coverage of new topics in the field. New and expanded sections include microbial ecology, high latitude systems and the cryosphere, climate and climate change, hydrothermal and cold seep systems. The structure of the work provides a modern presentation of the field, reflecting the input and different perspective of chemical, physical and biological oceanography, the specialized area of expertise of each of the three Editors-in-Chief. In this framework maximum attention has been devoted to making this an organic and unified reference. Represents a one-stop. organic information resource on the breadth of ocean science research Reflects the input and different perspective of chemical, physical and biological oceanography, the specialized area of expertise of each of the three Editors-in-Chief New and expanded sections include microbial ecology, high latitude systems and climate change Provides scientifically reliable information at a foundational level, making this work a resource for students as well as active researches

The Delft Sand, Clay and Rock Cutting Model
The Delft Sand, Clay and Rock Cutting Model

Author: S.A. Miedema

Publisher: IOS Press

Published: 2014-10-29

Total Pages: 572

ISBN-13: 1614994544

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Sand, clay and rock have to be excavated for a variety of purposes, such as dredging, trenching, mining (including deep sea mining), drilling, tunnel boring and many other applications. Many excavations take place on dry land, but they are also frequently required in completely saturated conditions, and the methods necessary to accomplish them consequently vary widely. This book provides an overview of cutting theories. It begins with a generic model, valid for all types of soil (sand, clay and rock), and continues with the specifics of dry sand, water-saturated sand, clay, atmospheric rock and hyperbaric rock. Small blade angles and large blade angles are discussed for each soil type, and for each case considered the equations/model for cutting forces, power and specific energy are given. With models verified by laboratory research, principally from the Delft University of Technology, and data from other recognized sources, this book will prove an invaluable reference for anybody whose work involves major excavations of any kind.