Ocean Gyre Ecosystems

2001 ◽  
pp. 1959-1965 ◽  
Author(s):  
M.P. Seki ◽  
J.J. Polovina
Keyword(s):  
Ocean Gyre

Barotropic variability in the presence of an ocean gyre

1990 ◽  
Vol 48 (1) ◽  
pp. 37-53 ◽  
Author(s):  
Richard J. Greatbatch ◽  
Jin Li
Keyword(s):  
Ocean Gyre

Ocean Gyre Ecosystems

2001 ◽  
pp. 132-137
Author(s):  
M.P. Seki ◽  
J.J. Polovina
Keyword(s):  
Ocean Gyre

Reduce the Plastic Debris: A Model Research on the Great Pacific Ocean Garbage Patch

2010 ◽  
Vol 113-116 ◽  
pp. 59-63 ◽  
Author(s):  
Yun Zhang ◽  
Yuan Biao Zhang ◽  
Ying Feng ◽  
Xiao Jin Yang
Keyword(s):  
Pacific Ocean ◽  
Detailed Analysis ◽  
Quantitative Model ◽  
Current Situation ◽  
Plastic Debris ◽  
Iterative Model ◽  
Model Research ◽  
The Future ◽  
Ocean Gyre

Based on the related current researches, this disquisition is focused on the problem of plastic debris in the Great Pacific Ocean Garbage Patch. From three aspects-the extent, density and distribution, this disquisition made a research on the current situation of the serious problem, and then put forward a quantitative model of the weight of plastic debris in the Pacifi Ocean Gyre. Besides, by limiting polystyrene takeout containers, we established an iterative model to predict the weight of plastic debris access to the sea per year in the future. After proving limiting polystyrene takeout containers could reduce the plastic debris effectively, we carry on a detailed analysis.

scholarly journals A Parasitic Arsenic Cycle That Shuttles Energy from Phytoplankton to Heterotrophic Bacterioplankton

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Stephen J. Giovannoni ◽  
Kimberly H. Halsey ◽  
Jimmy Saw ◽  
Omran Muslin ◽  
Christopher P. Suffridge ◽  
...  
Keyword(s):  
Field Experiments ◽  
Standing Stock ◽  
Methyl Groups ◽  
Sargasso Sea ◽  
Arsenic Compounds ◽  
Transfer Energy ◽  
Oxidation Rates ◽  
Arsenate Resistance ◽  
Abundant Phytoplankton ◽  
Ocean Gyre

ABSTRACTIn many regions of the world oceans, phytoplankton face the problem of discriminating between phosphate, an essential nutrient, and arsenate, a toxic analogue. Many phytoplankton, including the most abundant phytoplankton group known,Prochlorococcus, detoxify arsenate (AsV) by reduction to arsenite (AsIII), followed by methylation and excretion of the methylated arsenic products. We synthesized [14C]dimethyl arsenate (DMA) and used it to show that culturedPelagibacterstrain HTCC7211 (SAR11) cells oxidize the methyl group carbons of DMA, producing14CO2and ATP. We measured [14C]DMA oxidation rates in the P-depleted surface waters of the Sargasso Sea, a subtropical ocean gyre. [14C]DMA was oxidized to14CO2by Sargasso Sea plankton communities at a rate that would cause turnover of the estimated DMA standing stock every 8.1 days. SAR11 strain HTCC7211, which was isolated from the Sargasso Sea, has a pair of arsenate resistance genes and was resistant to arsenate, showing no growth inhibition at As/P ratios of >65:1. Across the global oceans, there was a strong inverse relationship between the frequency of the arsenate reductase (LMWPc_ArsC) inPelagibactergenomes and phosphate concentrations. We propose that the demethylation of methylated arsenic compounds byPelagibacterand possibly other bacterioplankton, coupled with arsenate resistance, results in the transfer of energy from phytoplankton to bacteria. We dub this a parasitic cycle because the release of arsenate byPelagibacterin principle creates a positive-feedback loop that forces phytoplankton to continually regenerate arsenate detoxification products, producing a flow of energy to P-limited ocean regions.IMPORTANCEIn vast, warm regions of the oceans, phytoplankton face the problem of arsenic poisoning. Arsenate is toxic because it is chemically similar to phosphate, a scarce nutrient that phytoplankton cells need for growth. Many phytoplankton, including the commonest phytoplankton type in warm oceans,Prochlorococcus, detoxify arsenate by adding methyl groups. Here we show that the most abundant non-photosynthetic plankton in the oceans, SAR11 bacteria, remove the methyl groups, releasing poisonous forms of arsenic back into the water. We postulate that the methylation and demethylation of arsenic compounds creates a cycle in which the phytoplankton can never get ahead and must continually transfer energy to the SAR11 bacteria. We dub this a parasitic process and suggest that it might help explain why SAR11 bacteria are so successful, surpassing all other plankton in their numbers. Field experiments were done in the Sargasso Sea, a subtropical ocean gyre that is sometimes called an ocean desert because, throughout much of the year, there is not enough phosphorous in the water to support large blooms of phytoplankton. Ocean deserts are expanding as the oceans absorb heat and grow warmer.

scholarly journals Argon as a Tracer of Cross-Isopycnal Mixing in the Thermocline

2006 ◽  
Vol 36 (11) ◽  
pp. 2090-2105 ◽  
Author(s):  
Cara C. Henning ◽  
David Archer ◽  
Inez Fung
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Vertical Mixing ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Global Ocean ◽  
Equatorial Pacific Ocean ◽  
Subsurface Waters ◽  
Different Temperatures ◽  
Ocean Gyre

Abstract Noble gases such as argon are unaffected by chemical reactions in the ocean interior, but a number of physical mechanisms can lead to measurable sea level atmospheric disequilibrium in subsurface waters of the ocean. One such mechanism is the mixing of waters of different temperatures, which can lead to supersaturation in the ocean interior. The authors simulate the supersaturation mixing signature in the thermocline in a global ocean general circulation model, Parallel Ocean Program model, version 1.4 (POP 1.4). In contrast to existing mixing diagnostics such as dye tracers or microstructure measurements, which yield the local, recent rate of diabatic mixing, argon disequilibrium traces an integrated lifetime history of subsurface mixing. A theoretical model of the subtropical Atlantic Ocean gyre is built, based on the competing time scales of horizontal and vertical mixing, that agrees well with the full general circulation model argon supersaturation gradient in the thermocline. These results suggest that gyre-scale argon data from the real ocean could be similarly interpreted. The variation of the argon supersaturation with diffusivity in the equatorial Pacific Ocean is also investigated.

NAPTRAM - Plastiktransportmechanismen, Senken und Interaktionen mit Biota im Nordatlantik / NAPTRAM - North Atlantic plastic transport mechanisms, sinks, and interactions with biota, Cruise No. SO279, Emden (Germany) – Emden (Germany), 04.12.2020 – 05.01.2021

2021 ◽  
Author(s):  
Aaron Beck
Keyword(s):  
Water Column ◽  
North Atlantic ◽  
Surface Waters ◽  
Open Ocean ◽  
Transport Pathways ◽  
The North ◽  
The North Atlantic ◽  
Vertical Export ◽  
Core Questions ◽  
Ocean Gyre

The coastal and open oceans represent a major, but yet unconstrained, sink for plastics. It is likely that plastic-biota interactions are a key driver for the fragmentation, aggregation, and vertical transport of plastic litter from surface waters to sedimentary sinks. Cruise SO279 conducted sampling to address core questions of microplastic distribution in the open ocean water column, biota, and sediments. Seven stations were sampled between the outer Bay of Biscay and the primary working area south of the Azores. Additional samples were collected from surface waters along the cruise track to link European coastal and shelf waters with the open ocean gyre. Microplastic samples coupled with geochemical tracer analyses will build a mechanistic understanding of MP transport and its biological impact reaching from coastal seas to the central gyre water column and sinks at the seabed. Furthermore, floating plastics were sampled for microbial community and genetic analyses to investigate potential enzymatic degradation pathways. Cruise SO279 served as the third cruise of a number of connected research cruises to build an understanding of the transport pathways of plastic and microplastic debris in the North Atlantic from the input through rivers and air across coastal seas into the accumulation spots in the North Atlantic gyre and the vertical export to its sink at the seabed. The cruise was an international effort as part of the JPI Oceans project HOTMIC (“HOrizontal and vertical oceanic distribution, Transport, and impact of MICroplastics”) and the BMBF funded project PLASTISEA (‘Harvesting the marine Plastisphere for novel cleaning concepts’), and formed a joint effort of HOTMIC and PLASTISEA researchers from a range of countries and institutes.

scholarly journals Interdecadal Variability of the Eastward Current in the South China Sea Associated with the Summer Asian Monsoon

2010 ◽  
Vol 23 (22) ◽  
pp. 6115-6123 ◽  
Author(s):  
Guihua Wang ◽  
Chunzai Wang ◽  
Rui Xin Huang
Keyword(s):  
South China Sea ◽  
Wind Stress ◽  
South China ◽  
Asian Monsoon ◽  
Interdecadal Variability ◽  
Wind Stress Curl ◽  
China Sea ◽  
Ocean Data Assimilation ◽  
Southward Shift ◽  
Ocean Gyre

Abstract Based on the Simple Ocean Data Assimilation (SODA) dataset and three types of Sverdrup streamfunction, an interdecadal variability of the eastward current in the middle South China Sea (SCS) during summer is identified. Both the pattern and strength of the summer Asian monsoon wind stress curl over the SCS contribute to the interdecadal variability of this current. From 1960 to 1979, the monsoon intensified and the zero wind stress curl line shifted southward. Both the core of positive wind stress curl in the northern SCS and the negative curl in the southern SCS moved southward and thus induced a southward shift of both the southern anticyclonic and northern cyclonic gyres, resulting in a southward displacement of the eastward current associated with these two gyres. In the meantime, the southern (northern) SCS anticyclonic (cyclonic) ocean gyre weakened (strengthened) and therefore also induced the southward shift of the eastward current near the intergyre boundary. In contrast, the eastward current shifted northward from 1980 to 1998 because the monsoon relaxed and the zero wind stress curl line shifted northward. After 1998, the eastward jet moved southward again as the zero wind stress curl line shifted southward and the SCS monsoon strengthened. The eastward current identified from the baroclinic streamfunction moved about 1.7° more southward than that from the barotropic streamfunction, indicating that the meridional position of the eastward current is depth dependent.

scholarly journals Genomic evidence for inter-class host transition between abundant streamlined heterotrophs by a novel and ubiquitous marine Methylophage

2021 ◽  
Author(s):  
Holger Heiko Buchholz ◽  
Luis M Bolaños ◽  
Ashley G Bell ◽  
Michelle L Michelsen ◽  
Mike Allen ◽  
...  
Keyword(s):  
Global Ocean ◽  
Sargasso Sea ◽  
English Channel ◽  
Free Living ◽  
Host Abundance ◽  
Marine Biogeochemistry ◽  
Transition Event ◽  
Ocean Gyre ◽  
Sar11 Clade ◽  
Marine Primary Production

The methylotrophic OM43 clade are Gammaproteobacteria that comprise some of the smallest free-living cells known with highly streamlined genomes. OM43 represents an important microbial link between marine primary production and return of carbon back to the atmosphere. Bacteriophages shape microbial communities and are major drivers of mortality and global marine biogeochemistry. Recent cultivation efforts have brought the first viruses infecting members of the OM43 clade into culture. Here we characterize a novel myophage infecting OM43, called Melnitz. Melnitz was isolated independently on three separate occasions (with isolates sharing >99.95% average nucleotide identity) from water samples from a subtropical ocean gyre (Sargasso Sea) and temperate coastal (Western English Channel) systems. Metagenomic recruitment from global ocean viromes confirmed that Melnitz is globally ubiquitous, congruent with patterns of host abundance. Bacteria with streamlined genomes such as OM43 and the globally dominant SAR11 clade use riboswitches as an efficient method to regulate metabolism. Melnitz encodes a two-piece tmRNA (ssrA), controlled by a glutamine riboswitch, providing evidence that riboswitch use also occurs for regulation during phage infection of streamlined heterotrophs. Virally encoded tRNAs and ssrA found in Melnitz were phylogenetically more closely related to those found within the alphaproteobacterial SAR11 clade and their associated myophages than those within their gammaproteobacterial hosts. This suggests the possibility of an ancestral inter-class host transition event between SAR11 and OM43. Melnitz and a related myophage that infects SAR11 were unable to infect hosts of the SAR11 and OM43, respectively, suggesting host transition rather than a broadening of host range.

scholarly journals Evidence for aggregation and export of cyanobacteria and nano-eukaryotes from the Sargasso Sea euphotic zone

2010 ◽  
Vol 7 (5) ◽  
pp. 7173-7206 ◽  
Author(s):  
M. W. Lomas ◽  
S. B. Moran
Keyword(s):  
Particle Size ◽  
Net Primary Production ◽  
Euphotic Zone ◽  
Sargasso Sea ◽  
Particle Size Fractions ◽  
Poc Export ◽  
Chlorophyll Precursor ◽  
Autotrophic Biomass ◽  
Ocean Gyre

Abstract. Pico-plankton and nano-plankton are generally thought to represent a negligible fraction of the total particulate organic carbon (POC) export flux in oligotrophic gyres due to their small size, slow individual sinking rates, and tight grazer control that leads to high rates of recycling in the euphotic zone. Based upon recent inverse modeling and network analysis however, it has been hypothesized that pico-plankton, including the cyanobacteria Synechococcus and Prochlorococcus, and nano-plankton contribute significantly to POC export, via formation of aggregates and consumption of those aggregates by mesozooplankton, in proportion to their contribution to net primary production. This study presents total suspended particulate (> 0.7 μm) and particle size-fractionated (10–20 μm, 20–53 μm, > 53 μm) pigment concentrations from within and below the euphotic zone in the oligotrophic subtropical North Atlantic, collected using Niskin bottles and large volume in-situ pumps, respectively. Results show the indicator pigments for Synechococcus, Prochlorococcus and nano-eukaryotes are; (1) found at depths down to 500 m, and; (2) essentially constant, relative to the sum of all indicator pigments, across particle size fractions ranging from 10 μm to > 53 μm. Based upon the presence of chlorophyll precursor and degradation pigments, and that in-situ pumps do not effectively sample fecal pellets, it is concluded that these pigments were redistributed to deeper waters on larger, more rapidly sinking aggregates. Using available pigment data and ancillary cruise data, these Synechococcus, Prochlorococcus and nano-plankton derived aggregates are estimated to contribute 2–13% (5 ± 4%), 1–20% (5 ± 7%), and 6–43% (23 ± 14%) of the total sediment trap POC flux measured on the same cruises, respectively. Furthermore, nano-eukaryotes contribute equally to POC export and autotrophic biomass, while cyanobacteria contributions to POC export are one-tenth of their contribution to autotrophic biomass. These field observations provide direct evidence that pico- and nano-plankton represent a significant contribution to the total POC export in this oligotrophic ocean gyre. We suggest that this pathway should be included in ecosystem models, particularly as oligotrophic regions are hypothesized to expand in areal extent with warming and increased stratification in the future.

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