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Climate change: chilled out in the ice-age Atlantic.

https://arctichealth.org/en/permalink/ahliterature95893
Source
Nature. 2003 Sep 4;425(6953):32-3
Publication Type
Article
Date
Sep-4-2003
Author
Mix Alan C
Source
Nature. 2003 Sep 4;425(6953):32-3
Date
Sep-4-2003
Language
English
Publication Type
Article
Keywords
Atlantic Ocean
Cold Climate
Fossils
Ice
Models, Theoretical
Plankton - physiology
Seasons
Temperature
PubMed ID
12955126 View in PubMed
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Decline of the marine ecosystem caused by a reduction in the Atlantic overturning circulation.

https://arctichealth.org/en/permalink/ahliterature95803
Source
Nature. 2005 Mar 31;434(7033):628-33
Publication Type
Article
Date
Mar-31-2005
Author
Schmittner Andreas
Author Affiliation
College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Admin. Bldg, Corvallis, Oregon 97331, USA. aschmittner@coas.oregonstate.edu
Source
Nature. 2005 Mar 31;434(7033):628-33
Date
Mar-31-2005
Language
English
Publication Type
Article
Keywords
Algorithms
Atlantic Ocean
Biomass
Cold Temperature
Computer simulation
Ecosystem
Greenhouse Effect
Marine Biology
Nitrates - analysis
Oceans and Seas
Plankton - physiology
Population Dynamics
Seawater - chemistry
Water Movements
Abstract
Reorganizations of the Atlantic meridional overturning circulation were associated with large and abrupt climatic changes in the North Atlantic region during the last glacial period. Projections with climate models suggest that similar reorganizations may also occur in response to anthropogenic global warming. Here I use ensemble simulations with a coupled climate-ecosystem model of intermediate complexity to investigate the possible consequences of such disturbances to the marine ecosystem. In the simulations, a disruption of the Atlantic meridional overturning circulation leads to a collapse of the North Atlantic plankton stocks to less than half of their initial biomass, owing to rapid shoaling of winter mixed layers and their associated separation from the deep ocean nutrient reservoir. Globally integrated export production declines by more than 20 per cent owing to reduced upwelling of nutrient-rich deep water and gradual depletion of upper ocean nutrient concentrations. These model results are consistent with the available high-resolution palaeorecord, and suggest that global ocean productivity is sensitive to changes in the Atlantic meridional overturning circulation.
PubMed ID
15800620 View in PubMed
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LC-MS-MS aboard ship: tandem mass spectrometry in the search for phycotoxins and novel toxigenic plankton from the North Sea.

https://arctichealth.org/en/permalink/ahliterature92886
Source
Anal Bioanal Chem. 2008 Nov;392(5):797-803
Publication Type
Article
Date
Nov-2008
Author
Krock Bernd
Tillmann Urban
John Uwe
Cembella Allan
Author Affiliation
Alfred-Wegener-Institut für Polar- und Meeresforschung, Am Handelshafen 12, 27570, Bremerhaven, Germany. bernd.krock@awi.de
Source
Anal Bioanal Chem. 2008 Nov;392(5):797-803
Date
Nov-2008
Language
English
Publication Type
Article
Keywords
Animals
Chromatography, Liquid - methods
Environmental monitoring
Food Contamination
Humans
Marine Toxins - analysis
North Sea
Plankton - physiology
Plants, Toxic - chemistry
Shellfish - analysis - toxicity
Spiro Compounds - analysis
Tandem Mass Spectrometry - methods
Abstract
Phycotoxins produced by various species of toxigenic microalgae occurring in the plankton are a global threat to the security of seafood resources and the health of humans and coastal marine ecosystems. This has necessitated the development and application of advanced methods in liquid chromatography coupled to mass spectrometry (LC-MS) for monitoring of these compounds, particularly in plankton and shellfish. Most such chemical analyses are conducted in land-based laboratories on stored samples, and thus much information on the near real-time biogeographical distribution and dynamics of phycotoxins in the plankton is unavailable. To resolve this problem, we conducted ship-board analysis of a broad spectrum of phycotoxins collected directly from the water column on an oceanographic cruise along the North Sea coast of Scotland, Norway, and Denmark. We equipped the ship with a triple-quadrupole linear ion-trap hybrid LC-MS-MS system for detection and quantitative analysis of toxins, such as domoic acid, gymnodimine, spirolides, dinophysistoxins, okadaic acid, pectenotoxins, yessotoxins, and azaspiracids (AZAs). We focused particular attention on the detection of AZAs, a group of potent nitrogenous polyether toxins, because the culprit species associated with the occurrence of these toxins in shellfish has been controversial. Marine toxins were analyzed directly from size-fractionated plankton net tows (20 microm mesh size) and Niskin bottle samples from discrete depths, after rapid methanolic extraction but without any further clean-up. Almost all expected phycotoxins were detected in North Sea plankton samples, with domoic acid and 20-methylspirolide G being most abundant. Although AZA was the least abundant of these toxins, the high sensitivity of the LC-MS-MS enabled detailed quantification, indicating that the highest amounts of AZA-1 were present in the southern Skagerrak in the 3-20 microm size-fraction. The direct on-board toxin measurements enabled isolation of plankton from stations with high AZA-1 levels and from the most suspicious size-fraction, i.e. most likely to contain the AZA-producer. A large number (>100) of crude cultures were established by serial dilution and later screened for the presence of AZAs after several weeks growth. From one crude culture containing AZA, a small dinoflagellate was subsequently isolated and brought into pure culture. We have thus proved that even sophisticated mass spectrometers can be operated in ship laboratories without any limitation caused by vibrations of the ship's engine or by wave movement during heavy seas at wind forces up to nine Beaufort. On-board LC-MS-MS is a valuable method for near real-time analysis of phycotoxins in plankton for studies on bloom dynamics and the fate of toxins in the food web, and for characterization and isolation of putatively toxigenic organisms.
PubMed ID
18584156 View in PubMed
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Marine pelagic ecosystems: the west Antarctic Peninsula.

https://arctichealth.org/en/permalink/ahliterature95645
Source
Philos Trans R Soc Lond B Biol Sci. 2007 Jan 29;362(1477):67-94
Publication Type
Article
Date
Jan-29-2007
Author
Ducklow Hugh W
Baker Karen
Martinson Douglas G
Quetin Langdon B
Ross Robin M
Smith Raymond C
Stammerjohn Sharon E
Vernet Maria
Fraser William
Author Affiliation
School of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA. duck@vims.edu
Source
Philos Trans R Soc Lond B Biol Sci. 2007 Jan 29;362(1477):67-94
Date
Jan-29-2007
Language
English
Publication Type
Article
Keywords
Animals
Antarctic Regions
Biomass
Carbon - analysis
Ecosystem
Euphausiacea - physiology
Geologic Sediments - analysis
Greenhouse Effect
Ice Cover
Mammals - physiology
Oceanography
Oceans and Seas
Plankton - physiology
Population Density
Population Dynamics
Spheniscidae - physiology
Temperature
Abstract
The marine ecosystem of the West Antarctic Peninsula (WAP) extends from the Bellingshausen Sea to the northern tip of the peninsula and from the mostly glaciated coast across the continental shelf to the shelf break in the west. The glacially sculpted coastline along the peninsula is highly convoluted and characterized by deep embayments that are often interconnected by channels that facilitate transport of heat and nutrients into the shelf domain. The ecosystem is divided into three subregions, the continental slope, shelf and coastal regions, each with unique ocean dynamics, water mass and biological distributions. The WAP shelf lies within the Antarctic Sea Ice Zone (SIZ) and like other SIZs, the WAP system is very productive, supporting large stocks of marine mammals, birds and the Antarctic krill, Euphausia superba. Ecosystem dynamics is dominated by the seasonal and interannual variation in sea ice extent and retreat. The Antarctic Peninsula is one among the most rapidly warming regions on Earth, having experienced a 2 degrees C increase in the annual mean temperature and a 6 degrees C rise in the mean winter temperature since 1950. Delivery of heat from the Antarctic Circumpolar Current has increased significantly in the past decade, sufficient to drive to a 0.6 degrees C warming of the upper 300 m of shelf water. In the past 50 years and continuing in the twenty-first century, the warm, moist maritime climate of the northern WAP has been migrating south, displacing the once dominant cold, dry continental Antarctic climate and causing multi-level responses in the marine ecosystem. Ecosystem responses to the regional warming include increased heat transport, decreased sea ice extent and duration, local declines in icedependent Adélie penguins, increase in ice-tolerant gentoo and chinstrap penguins, alterations in phytoplankton and zooplankton community composition and changes in krill recruitment, abundance and availability to predators. The climate/ecological gradients extending along the WAP and the presence of monitoring systems, field stations and long-term research programmes make the region an invaluable observatory of climate change and marine ecosystem response.
PubMed ID
17405208 View in PubMed
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The rise and fall of species: implications for macroevolutionary and macroecological studies.

https://arctichealth.org/en/permalink/ahliterature95607
Source
Proc Biol Sci. 2007 Nov 7;274(1626):2745-52
Publication Type
Article
Date
Nov-7-2007
Author
Liow Lee Hsiang
Stenseth Nils Chr
Author Affiliation
Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066 Blindern, Oslo N-0316, Norway. l.h.liow@bio.uio.no
Source
Proc Biol Sci. 2007 Nov 7;274(1626):2745-52
Date
Nov-7-2007
Language
English
Publication Type
Article
Keywords
Diatoms - physiology
Ecosystem
Evolution
Fossils
Plankton - physiology
Population Dynamics
Time Factors
Abstract
Knowing the geographic extents of species is crucial for understanding the causes of diversity distributions and modes of speciation and extinction. Species geographic ranges are often viewed as approximately constant in size in geological time, even though climate change studies have shown that historical and modern species geographic distributions are not static. Here, we use an extensive global microfossil database to explore the temporal trajectories of geographic extents over the entire lifespan of marine nannoplankton, diatom, planktic foraminifer and radiolarian species. We show that geographic extents are not static over geological time-scales. Temporal trajectories of species geographic ranges are asymmetric: the rise is quicker than the fall. We propose that once a species has overcome its initial difficulties in geographic establishment, it rises to its peak geographic extent. However, once this peak value is reached, it will also have a maximal number of species to interact with. The negative of these biotic interactions could then cause a gradual geographic decline. We discuss the multiple implications of our findings with reference to macroecological and macroevolutionary studies.
PubMed ID
17711843 View in PubMed
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