Ocean ecosystems

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  • Overharvesting has led to severe reductions in the abundance and range of nearly every large vertebrate species that humans have ever found worth pursuing. These megafaunal reductions, dating in some cases from first contact with early peoples (Martin 1973), are widely known. In contrast, remarkably little is known about the ecological consequences of megafaunal extirpations. Whales and whaling are part of that legacy. Most people know that large whales have been depleted, but little thought has been given to how the depletions may have influenced ocean ecosystems.

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  • Human activities are affecting the global environment in myriad ways, with numerous direct and indirect effects on ecosystems. The climate and atmospheric composition of Earth are changing rapidly. Humans have directly modified half of the ice-free terrestrial surface and use 40% of terrestrial production. Our actions are causing the sixth major extinction event in the history of life on Earth and are radically modifying the interactions among forests, fields, streams, and oceans.

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  • The ocean absorbs a significant portion of carbon dioxide (CO2) emissions from human activities, equivalent to about one-third of the total emissions for the past 200 years from fossil fuel combustion, cement production and land use change (Sabine et al., 2004). Uptake of CO2 by the ocean benefits society by moderating the rate of climate change but also causes unprecedented changes to ocean chemistry, decreasing the pH of the water and leading to a suite of chemical changes collectively known as ocean acidification.

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  • Challenges to sustaining the productivity of oceanic and coastal fisheries have become more critical and complex as these fisheries reach the upper limits to ocean harvests. In addition, it is now clear that we are managing interactive and dynamic food webs rather than sets of independent single-species populations.

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  • The Pacific Ocean isn’t just the deepest and largest ocean. It is also home to one of the world’s most amazing natural wonders: the Great Barrier Reef. Located off of the northeastern coast of Australia, the Great Barrier Reef is 210 separate coral reefs that stretch for more than 1,260 miles (2,028 kilometers) around northern Australia. Th e Great Barrier Reef is full of some of the most amazing, beautiful, and deadly sea creatures on the planet, including the Irukandji jellyfi sh and the great white shark....

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  • Two hundred years ago, Lewis and Clark led their “Corps of Discovery” on an unprecedented expedition to explore the vast dimensions of the nation’s longest and largest river basin—the Missouri. Their central charge was to seek a water route to the Pacific Ocean to support commerce and development. Since those early days, the Missouri River and its tributaries have occupied a unique place in United States history.

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  • This book began its evolution in 1999 when the British Antarctic Survey, where I worked at the time, began a new research programme on the management of marine ecosystems. This programme concentrated upon the krill-based ecosystem at SouthGeorgia which has been the subject of almost continuous study since the Discovery Expeditions in the 1920s. Latterly, international efforts to understand the dynamics of this ecosystem and the wider Southern Ocean have been coordinated by the Commission for the Conservation of AntarcticMarine Living Resources (CCAMLR)....

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  • The concept of marine reserves has been repeatedly addressed in the past 25 years, but implementation and subsequent evaluation of these protected areas has been relatively infrequent until the past decade. In recent years, there has been strong advocacy for reserves among the conservation community and those concerned about losses of habitat and biodiversity in the sea.

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  • Importance of Coral Reefs: 0.2% of world’s ocean. Habitat for 1/3 of marine fishes. Habitat for tens of thousands of other animals. The rainforests of the oceans. Destruction of other ecosystems upon which coral reefs depend. Possible disruption of reproduction and recruitment.

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  • These research teams study for example the impact and mechanisms of greenhouse gas emissions and atmospheric pollutant on climate, ozone depletion and carbon sinks (oceans and inland waters, forests and soil). They do research to understand the mechanisms and assess the impact of global change on the water cycle, water quality and availability, as well as soil functions and quality to provide the bases for management tools for sustainable water systems. Biodiversity and ecosystems are analysed to understand and minimise the negative impacts of human activities.

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  • Committed to ensuring the long-term conservation and sustainable use of fishery resources in the South Pacific Ocean and in so doing safeguarding the marine ecosystems in which the resources occur; Recalling relevant international law as reflected in the United Nations Convention on the Law of the Sea of 10 December 1982, the Agreement for the Implementation of the Provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks of 4 December 1995 and the Agreement to...

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  • left panels). This ridge separates the Atlantic Ocean southwest of the ridge from the Norwegian Sea to the northeast. The sill of the ridge reaches different depths in different areas. Most of it is shallower than 500 m, but a small part is deeper with the Faroe Bank Channel being the deepest passage across the ridge. The upper layers of the waters surrounding the Faroes are dominated by ‘Modified North Atlantic Water’ which derives from the North Atlantic Current flowing towards the east and north-east (Hansen and Østerhus, 2000) (Figure 4.1.1.1, upper left panel).

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  • This volume, the first in a series, presents the findings of an ambitious project—to measure the impact of fishing on the ecosystems that make up the North Atlantic Ocean and to propose ways to mitigate that impact. The project arose from a request by Dr. Joshua Reichert, the Director of the Environment Program of the Pew Charitable Trusts, Philadelphia, to answer six specific questions about the North Atlantic: • What are the total fisheries catches from the ecosystems, including reported and unreported landings and discards at sea?...

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  • Coastal Ecosystems. Africa has three coastlines—along the Mediterranean Sea in the north, the Atlantic Ocean in the west, and the Indian Ocean in the east. These shores consist of stretches of sand, soil, or rock. In general, plants and animals on Africa’s western coast are less varied and numerous than on the eastern coast. The coastal environments of Africa include coral reef, lagoon, mangrove, salt marsh, and seagrass ecosystems.

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  • Weather natural hazards, the environment and climate change are of concern to all of us. Especially, it is essential to understand how human activities might impact the nature. Hence, monitoring, research, and forecasting is of the outmost importance. Furthermore, climate change and pollution of the environment do not obey national borders; so, international collaboration on these issues is indeed extremely important.

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  • UNIT 2 : BIOMES AND ECOSYSTEMS Influenced by latitude, elevation, and associated moisture and temperature regimes, terrestrial biomes vary geographically from the tropics through the arctic and include various types of forest, grassland, shrub land, and desert. These biomes also include their associated freshwater communities: streams, lakes, ponds, and wetlands. Marine environments, also considered biomes by some ecologists, comprise the open ocean, littoral (shallow water) regions, benthic (bottom) regions, rocky shores, sandy shores, estuaries, and associated tidal marshes.

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  • Water contamination weakens or destroys natural ecosystems that support human health, food production, and biodiversity. Studies have estimated that the value of ecosystem services is double the gross national product of the global economy, and the role of freshwater ecosystems in purifying water and assimilating wastes has been valued at US$ 400 billion (2008$) (Costanza et al. 1997). Freshwater ecosystems are among the most degraded on the planet, and have suffered proportionately greater species and habitat losses than terrestrial or marine ecosystems (Revenga et al. 2000).

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  • 6 Ecosystems have complex dynamics (growth and development) 6.1 VARIABILITY IN LIFE CONDITIONS All known life on earth resides in the thin layer enveloping the globe known as the ecosphere. This region extends from sea level to 10 km into the ocean depths and approximately

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  • From microorganisms to whales, from single cells to complex organisms, from plants to animals to fungi, from body plans to behavior, the diversity of life is amazing. Living organisms have a profound impact on our physical world of ocean, landscape, and climate; around us is a multitude of diverse ecosystems that provide a livable environment and many valuable resources. The study of life—biology—is a multifaceted endeavor that uses observation, exploration, and experiments to gather information and test hypotheses about topics ranging from climate change to stem cells.

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  • Freshwater sources and oceans have an amazing natural ability to break down some waste materials, but not in the quantities discarded by today' s society. The overload that results eventually puts the ecosystem out of balance. Sometimes nature itself can create these imbalances. But most often our waterways are being polluted by municipal, agricultural and industrial wastes, including many toxic synthetic chemicals which cannot be broken down at all by natural processes.

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