نتایج جستجو برای: marine ecosystem

تعداد نتایج: 167762  

2003
D. A. HANSELL

likely, therefore, that allowance for the fixation of organic carbon as both DOC and POC would tend to reduce the ratio of I : PP in oligotrophic versus eutrophic systems. In conclusion, I disagree with Calbet (2001, p. 1828) that ‘‘the relative importance of microand mesozooplankton in the food dynamics of marine ecosystems, as well as the role of mesozooplankton grazing, must be reevaluated.’...

2013
Woodley

Introduction Degradation of the world's coral reefs is one of the most vivid examples of the effects of global environmental damage of marine ecosystems. The major stressors responsible for coral reef decline have been attributed to coastal urban and industrial development, agricultural activity, sedimentation, overharvesting, marine pollution, disease and climate change Reef species experienci...

2017
Quentin Hanich

Seafood is increasingly marketed as the clean, healthy choice for consumers – full of good oils and proteins and low in fat – with canned tuna a favourite cheap source of healthy protein. But science provides everworsening reports on the state of many fisheries, and their effect on marine ecosystems. As international conservation negotiations flounder, consumers and industry are increasingly re...

2014
Kevin R. Arrigo Donald K. Perovich Robert S. Pickart Zachary W. Brown Gert L. van Dijken Kate E. Lowry Matthew M. Mills Molly A. Palmer William M. Balch Nicholas R. Bates Claudia R. Benitez-Nelson Emily Brownlee Karen E. Frey Samuel R. Laney Jeremy Mathis Atsushi Matsuoka B. Greg Mitchell G.W.K. Moore Rick A. Reynolds Heidi M. Sosik James H. Swift

In the Arctic Ocean, phytoplankton blooms on continental shelves are often limited by light availability, and are therefore thought to be restricted to waters free of sea ice. During July 2011 in the Chukchi Sea, a large phytoplankton bloom was observed beneath fully consolidated pack ice and extended from the ice edge to 4100 km into the pack. The bloom was composed primarily of diatoms, with ...

1999
L. Legendre F. Rassoulzadegan J. Michaud

A new approach is described to identify the dominant process (physical versus biological) in a pelagic marine ecosystem, from simple biological oceanographic field variables. The approach is based on quantification of the matching (M) between phytoplankton production (P) and losses, from field estimates of chlorophyll a (Chl) and P. Coefficient M is estimated for a wide range of oceanic and coa...

2012
Jenifer K. McIntyre David H. Baldwin David A. Beauchamp Nathaniel L. Scholz

2. Additional Articles a. Common patterns, common drivers: comparative analysis of aggregate surplus production across ecosystems b. Comparative analysis of cod and herring production dynamics across thirteen northern marine ecosystems c. Aggregate surplus production models for demersal fishery resources of the Gulf of Maine d. Synthesizing lessons learned from comparing fisheries production in...

2003
Poul Holm

This paper examines the relationship between history and science with regard to the marine environment. It argues that historians and scientists should collaborate to reconstruct past ecosystems. Such collaboration to shed some light on the reasons why the life in the oceans appears as it does today. With this objective in view, a global research program has been established. The History of mar...

2004
P. A. Livingston K. Aydin J. Boldt J. Jurado-Molina

Assessment of the historical, present, and future states of marine ecosystems and the effects that humans and climate have on the state of an ecosystem are crucial to the scientific advice required to implement an ecosystem-based fishery management system. Management of federal groundfish fisheries in Alaska considers not just the target fishery, but also the possible impact those fisheries mig...

2013
Sarah Lena Eggers Birte Matthiessen

Climate change has the potential to profoundly influence the community structure and function of marine ecosystems. Prior to testing the consequences of altered environmental conditions on ecosystem functioning, it is first necessary to better understand how the functioning of an ecosystem is affected by its structure. Using phytoplankton communities with 4 naturally co-occurring coccolithophor...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده فنی 1388

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