scholarly journals Oxygen penetration deep into the sediment of the South Pacific gyre

2009 ◽  
Vol 6 (2) ◽  
pp. 3159-3186 ◽  
Author(s):  
J. P. Fischer ◽  
T. G. Ferdelman ◽  
S. D'Hondt ◽  
H. Røy ◽  
F. Wenzhöfer
Keyword(s):  
Primary Production ◽  
South Pacific ◽  
Oxygen Flux ◽  
Ex Situ ◽  
Sediment Layer ◽  
The South ◽  
Oxygen Penetration ◽  
Respiration Rates ◽  
South Pacific Gyre ◽  
Oxygen Profiles

Abstract. Benthic microbial oxygen consumption rates were investigated during an IODP site survey to the South Pacific Gyre. Primary production, particle fluxes and sedimentation rates are extraordinarily low in this most oligotrophic oceanic region on earth. We studied benthic microbial respiration rates from vertical oxygen profiles in sediments obtained on different spatial scales ex situ (in piston cores and multi cores), and in situ (using a benthic lander with a microelectrode profiler). Along a transect in the area 24 to 46° S and 165 to 117° W, cores at 10 of 11 sites were oxygenated for their entire lengths (as much as 8 m below seafloor), at concentrations >150 μmol L−1 O2. This represents the deepest oxygen penetration ever measured in marine sediments. Microprofiles from the top sediment layer revealed a diffusive oxygen flux to the sediment in the order of 0.2 mmol m−2 d−1. This is in the lower range of previously reported fluxes for oligotrophic sediments but corresponds well to the low surface water primary production. Because of the inert nature of the deeper sediment, oxygen that is not consumed in the surface layer diffuses downward to much greater depth. In deeper zones, a small O2 flux of ~0.1 μmol m−2 d−1 was therefore still present. This flux was constant with depth, indicating extremely low respiration rates. Modeling of the measured oxygen profiles suggests that the sediment is probably oxygenated down to the basalt, indicating an oxygen flux from the sediment into the basaltic basement.

scholarly journals Oxygen penetration deep into the sediment of the South Pacific gyre

2009 ◽  
Vol 6 (8) ◽  
pp. 1467-1478 ◽  
Author(s):  
J. P. Fischer ◽  
T. G. Ferdelman ◽  
S. D'Hondt ◽  
H. Røy ◽  
F. Wenzhöfer
Keyword(s):  
Primary Production ◽  
South Pacific ◽  
Ex Situ ◽  
Sediment Layer ◽  
O2 Consumption ◽  
The South ◽  
Oxygen Penetration ◽  
Consumption Rates ◽  
South Pacific Gyre ◽  
Oxygen Profiles

Abstract. Sediment oxygen concentration profiles and benthic microbial oxygen consumption rates were investigated during an IODP site survey in the South Pacific Gyre. Primary production, particle fluxes and sedimentation rates are extremely low in this ultra-oligotrophic oceanic region. We derived O2 consumption rates from vertical oxygen profiles in sediments obtained on different spatial scales ex situ (in piston cores and multi cores), and in situ (using a benthic lander equipped with a microelectrode profiler). Along a transect in the area 24 to 46° S and 165 to 117° W, cores from 10 out of 11 sites were oxygenated over their entire length (as much as 8 m below seafloor), with deep O2 concentrations >150 μmol L−1. This represents the deepest oxygen penetration ever measured in marine sediments. High-resolution microprofiles from the surface sediment layer revealed a diffusive oxygen uptake between 0.1 and 1.3 mmol m−2 d−1, equal to a carbon mineralization rate of ~0.4–4.5 gC m−2 yr−1. This is in the lower range of previously reported fluxes for oligotrophic sediments but corresponds well to the low surface water primary production. Half of the pool of reactive organic matter was consumed in the top 1.5–6 mm of the sediment. Because of the inert nature of the deeper sediment, oxygen that is not consumed within the top centimeters diffuses downward to much greater depth. In deeper zones, a small O2 flux between 0.05 and 0.3 μmol m−2 d−1 was still present. This flux was nearly constant with depth, indicating extremely low O2 consumption rates. Modeling of the oxygen profiles suggests that the sediment is probably oxygenated down to the basalt, suggesting an oxygen flux from the sediment into the basaltic basement.

scholarly journals Heterotrophic bacterial production in the South East Pacific: longitudinal trends and coupling with primary production

2007 ◽  
Vol 4 (4) ◽  
pp. 2761-2791 ◽  
Author(s):  
F. Van Wambeke ◽  
I. Obernosterer ◽  
T. Moutin ◽  
S. Duhamel ◽  
O. Ulloa ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Bacterial Production ◽  
South Pacific ◽  
Leucine Incorporation ◽  
The South ◽  
Phytoplankton Primary Production ◽  
East Pacific ◽  
Wide Range ◽  
South Pacific Gyre

Abstract. Spatial variations of heterotrophic bacterial production and phytoplankton primary production were investigated across South East Pacific Ocean (–141° W, –8° S to –72° W, –35° S) in November–December 2004. Bacterial production (³H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m−2 d−1 in the hyper-oligotrophic South Pacific Gyre to 392 mg C m−2 d−1 in the upwelling off Chile. Within the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg TChla m−2) were obtained and in situ 14C based particulate primary production rates were as low as 153 mg C m−2 d−1, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. In the South Pacific gyre average rates of ³H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol L−1 h−1 and 15–56×10−21 mol cell−1 h−1, respectively), were in the same range as those reported for other oligotrophic sub tropical and temperate waters. Rates of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O2 m−2 d−1), except for one station in the upwelling off Chile (245 mmol O2 m−2 d−1). Bacterial growth efficiencies varied between 5 and 38% and bacterial carbon demand largely exceeded 14C particulate primary production across the South Pacific Ocean. Net community production also revealed negative values in the South Pacific Gyre (–13±20 to –37±40 mmol O2 m−2 d−1). Such imbalances being impossible in this area far from any external input, we discuss the techniques involved for determining the coupling between primary production and bacterial heterotrophic production.

scholarly journals Heterotrophic bacterial production in the eastern South Pacific: longitudinal trends and coupling with primary production

2008 ◽  
Vol 5 (1) ◽  
pp. 157-169 ◽  
Author(s):  
F. Van Wambeke ◽  
I. Obernosterer ◽  
T. Moutin ◽  
S. Duhamel ◽  
O. Ulloa ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Bacterial Production ◽  
South Pacific ◽  
Leucine Incorporation ◽  
The South ◽  
Phytoplankton Primary Production ◽  
South Pacific Ocean ◽  
Wide Range ◽  
South Pacific Gyre

Abstract. Spatial variation of heterotrophic bacterial production and phytoplankton primary production were investigated across the eastern South Pacific Ocean (−141° W, −8° S to −72° W, −35° S) in November–December 2004. Bacterial production (3H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m−2 d−1 in the hyper-oligotrophic South Pacific Gyre to 392 mg C m−2 d−1 in the upwelling off Chile. In the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg Total Chla m−2) were obtained and fluxes of in situ 14C-based particulate primary production were as low as 153 mg C m−2 d−1, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. Average rates of 3H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol l−1 h−1 and 15–56×10−21 mol cell−1 h−1, respectively) determined in the South Pacific gyre, were in the same range as those reported for other oligotrophic subtropical and temperate waters. Fluxes of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O2 m−2 d−1), except for one station in the upwelling off Chile (245 mmol O2 m−2 d−1). Bacterial growth efficiencies varied between 5 and 38%. Bacterial carbon demand largely exceeded 14C particulate primary production across the South Pacific Ocean, but was lower or equal to gross community production.

scholarly journals Volume distribution for particles between 3.5 to 2000 μm in the upper 200 m region of the South Pacific Gyre

2008 ◽  
Vol 5 (2) ◽  
pp. 299-310 ◽  
Author(s):  
L. Stemmann ◽  
D. Eloire ◽  
A. Sciandra ◽  
G. A. Jackson ◽  
L. Guidi ◽  
...  
Keyword(s):  
Weight Ratio ◽  
South Pacific ◽  
Dry Weight ◽  
Volume Distribution ◽  
The South ◽  
Size Spectra ◽  
Marquesas Islands ◽  
Large Particles ◽  
Living Organisms ◽  
South Pacific Gyre

Abstract. The French JGOFS BIOSOPE cruise crossed the South Pacific Gyre (SPG) on a transect between the Marquesas Islands and the Chilean coast on a 7500 km transect (8° S–34° S and 8° W–72° W). The number and volume distributions of small (3.5100 μm) were analysed combining two instruments, the HIAC/Royco Counter (for the small particles) and the Underwater Video Profiler (UVP, for the large particles). For the HIAC analysis, samples were collected from 12 L CTD Rosette bottles and immediately analysed on board while the UVP provided an estimate of in situ particle concentrations and size in a continuous profile. Out of 76 continuous UVP and 117 discrete HIAC vertical profiles, 25 had both sets of measurements, mostly at a site close to the Marquesas Islands (site MAR) and one in the center of the gyre (site GYR). At GYR, the particle number spectra from few μm to few mm were fit with power relationships having slopes close to −4. At MAR, the high abundance of large objects, probably living organisms, created a shift in the full size spectra of particles such that a single slope was not appropriate. The small particle pool at both sites showed a diel pattern while the large did not, implying that the movement of mass toward the large particles does not take place at daily scale in the SPG area. Despite the relatively simple nature of the number spectra, the volume spectra were more variable because what were small deviations from the straight line in a log-log plot were large variations in the volume estimates. In addition, the mass estimates from the size spectra are very sensitive to crucial parameters such as the fractal dimension and the POC/Dry Weight ratio. Using consistent values for these parameters, we show that the volume of large particles can equal the volume of the smaller particles. However the proportion of material in large particles decreased from the mesotrophic conditions at the border of the SPG to the ultra-oligotrophy of the center in the upper 200 m depth. We expect large particles to play a major role in the trophic interaction in the upper waters of the South Pacific Gyre.

scholarly journals Microbial community composition and nitrogen availability influence DOC remineralization in the South Pacific Gyre

2015 ◽  
Vol 177 ◽  
pp. 325-334 ◽  
Author(s):  
Robert T. Letscher ◽  
Angela N. Knapp ◽  
Anna K. James ◽  
Craig A. Carlson ◽  
Alyson E. Santoro ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Nitrogen Availability ◽  
Microbial Community Composition ◽  
South Pacific ◽  
The South ◽  
South Pacific Gyre

scholarly journals Dust, volcanic ash, and the evolution of the South Pacific Gyre through the Cenozoic

2015 ◽  
Vol 30 (8) ◽  
pp. 1078-1099 ◽  
Author(s):  
Ann G. Dunlea ◽  
Richard W. Murray ◽  
Justine Sauvage ◽  
Arthur J. Spivack ◽  
Robert N. Harris ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
South Pacific ◽  
The South ◽  
South Pacific Gyre

Hyperiid amphipods in the eastern part of the South Pacific gyre

1991 ◽  
Vol 109 (2) ◽  
pp. 259-265 ◽  
Author(s):  
G. M. Vinogradov
Keyword(s):  
South Pacific ◽  
The South ◽  
South Pacific Gyre

scholarly journals IODP Expedition 329: Life and Habitability Beneath the Seafloor of the South Pacific Gyre

2013 ◽  
Vol 15 ◽  
pp. 4-10 ◽  
Author(s):  
S. D'Hondt ◽  
F. Inagaki ◽  
C. Alvarez Zarikian ◽  
Keyword(s):  
Solid Phase ◽  
South Pacific ◽  
Fluid Replacement ◽  
The South ◽  
Ocean Drilling Program ◽  
Sediment Column ◽  
Ocean Drilling ◽  
Integrated Ocean Drilling Program ◽  
Cell Counts ◽  
South Pacific Gyre

Integrated Ocean Drilling Program (IODP) Expedition 329 made major strides toward fulfilling its objectives. Shipboard studies documented (1) fundamental aspects of habitability and life in this very low activity subseafloor sedimentary ecosystem and (2) first-order patterns of habitability within the igneous basement. A broad range of postexpedition studies will complete the expedition objectives. Throughout the South Pacific Gyre (SPG; Sites U1365–U1370), dissolved oxygen and nitrate are present throughout the entire sediment sequence, and sedimentary microbial cell counts are lower than at all previously drilled IODP/ Ocean Drilling Program (ODP)/Deep Sea Drilling Program (DSDP) sites. In contrast, at Site U1371 in the upwelling zone just south of the gyre, detectable oxygen and nitrate are limited to the top and bottom of the sediment column, manganese reduction is a prominent electron-accepting process, and cell concentrations are higher than at the same depths in the SPG sites throughout the sediment column. Geographic variation in subseafloor profiles of dissolved and solid-phase chemicals are consistent with the magnitude of organic-fueled subseafloor respiration declining from outside the gyre to the gyre center. <br><br> Chemical profiles in the sedimentary pore water and secondary mineral distributions in the basaltic basement indicate that basement alteration continues on the timescale of formation fluid replacement, even at the sites with the oldest basement (84–120 Ma at Sites U1365 and U1366). <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.15.01.2013" target="_blank">10.2204/iodp.sd.15.01.2013</a>

scholarly journals Amborella trichopoda

2011 ◽  
pp. 143-154
Author(s):  
Bernadette Grosse-Veldmann ◽  
Nadja Korotkova ◽  
Bernhard Reinken ◽  
Wolfram Lobin ◽  
Wilhelm Barthlott
Keyword(s):  
Ex Situ Conservation ◽  
New Caledonia ◽  
South Pacific ◽  
Ex Situ ◽  
Pacific Island ◽  
Botanic Gardens ◽  
The South ◽  
South Pacific Island ◽  
The World ◽  
The University

Amborella trichopoda Baill., the most ancestral angiosperm, has been successfully cultivated in the Botanic Gardens of the University of Bonn in Germany (BG Bonn) for more than a decade. The distribution of this plant – limited to the South Pacific island of New Caledonia – and its cultivation has so far only been achieved in a few botanic gardens. This paper provides details about the cultivation and propagation of Amborella, and information on its cultivation in botanic gardens around the world. The authors propose that the collections of this plant in botanic gardens could be used to establish ex situ conservation collections.

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