scholarly journals Nutrient limitation of primary productivity in the Southeast Pacific (BIOSOPE cruise)

2008 ◽  
Vol 5 (1) ◽  
pp. 215-225 ◽  
Author(s):  
S. Bonnet ◽  
C. Guieu ◽  
F. Bruyant ◽  
O. Prášil ◽  
F. Van Wambeke ◽  
...  
Keyword(s):  
Primary Productivity ◽  
World Ocean ◽  
Dinitrogen Fixation ◽  
Global Ocean ◽  
Physiological Status ◽  
Phytoplankton Productivity ◽  
The North ◽  
Southeast Pacific ◽  
Essential Nutrient ◽  
South Pacific Gyre

Abstract. Iron is an essential nutrient involved in a variety of biological processes in the ocean, including photosynthesis, respiration and dinitrogen fixation. Atmospheric deposition of aerosols is recognized as the main source of iron for the surface ocean. In high nutrient, low chlorophyll areas, it is now clearly established that iron limits phytoplankton productivity but its biogeochemical role in low nutrient, low chlorophyll environments has been poorly studied. We investigated this question in the unexplored southeast Pacific, arguably the most oligotrophic area of the global ocean. Situated far from any continental aerosol source, the atmospheric iron flux to this province is amongst the lowest of the world ocean. Here we report that, despite low dissolved iron concentrations (~0.1 nmol l−1) across the whole gyre (3 stations located in the center and at the western and the eastern edges), primary productivity are only limited by iron availability at the border of the gyre, but not in the center. The seasonal stability of the gyre has apparently allowed for the development of populations acclimated to these extreme oligotrophic conditions. Moreover, despite clear evidence of nitrogen limitation in the central gyre, we were unable to measure dinitrogen fixation in our experiments, even after iron and/or phosphate additions, and cyanobacterial nif H gene abundances were extremely low compared to the North Pacific Gyre. The South Pacific gyre is therefore unique with respect to the physiological status of its phytoplankton populations.

scholarly journals Nutrients limitation of primary productivity in the Southeast Pacific (BIOSOPE cruise)

2007 ◽  
Vol 4 (4) ◽  
pp. 2733-2759 ◽  
Author(s):  
S. Bonnet ◽  
C. Guieu ◽  
F. Bruyant ◽  
O. Prášil ◽  
F. Van Wambeke ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Primary Productivity ◽  
Nifh Gene ◽  
World Ocean ◽  
Global Ocean ◽  
Physiological Status ◽  
Phytoplankton Productivity ◽  
The North ◽  
Southeast Pacific ◽  
Essential Nutrient

Abstract. Iron is an essential nutrient involved in a variety of biological processes in the ocean, including photosynthesis, respiration and nitrogen fixation. Atmospheric deposition of aerosols is recognized as the main source of iron for the surface ocean. In high nutrient, low chlorophyll areas, it is now clearly established that iron limits phytoplankton productivity but its biogeochemical role in low nutrient, low chlorophyll environments has been poorly studied. We investigated this question in the unexplored southeast Pacific, arguably the most oligotrophic area of the global ocean. Situated far from any continental aerosol source, the atmospheric iron flux to this province is amongst the lowest of the world ocean. Here we report that, despite low dissolved iron concentrations (~0.1 nmol l−1) measured across the whole gyre (3 stations situated in the center, the western and the eastern edge), photosynthesis and primary productivity are only limited by iron availability at the border of the gyre, but not in the center. The seasonal stability of the gyre has apparently allowed for the development of populations acclimated to these extreme oligotrophic conditions. Moreover, despite clear evidence of nitrogen limitation in the central gyre, we were unable to measure nitrogen fixation in our experiments, even after iron and/or phosphate additions, and cyanobacterial nifH gene abundances were extremely low compared to the North Pacific Gyre. The South Pacific gyre is therefore unique with respect to the physiological status of its phytoplankton populations.

scholarly journals Assimilation of Radiocarbon and Chlorofluorocarbon Data to Constrain Deep and Bottom Water Transports in the World Ocean

2007 ◽  
Vol 37 (2) ◽  
pp. 259-276 ◽  
Author(s):  
Reiner Schlitzer
Keyword(s):  
Southern Ocean ◽  
North Atlantic ◽  
Bottom Water ◽  
World Ocean ◽  
Weddell Sea ◽  
Global Ocean ◽  
Western Boundary ◽  
Boundary Current ◽  
The North ◽  
The North Atlantic

Abstract A coarse-resolution global model with time-invariant circulation is fitted to hydrographic and tracer data by means of the adjoint method. Radiocarbon and chlorofluorocarbon (CFC-11 and CFC-12) data are included to constrain deep and bottom water transport rates and spreading pathways as well as the strength of the global overturning circulation. It is shown that realistic global ocean distributions of hydrographic parameters and tracers can be obtained simultaneously. The model correctly reproduces the deep ocean radiocarbon field and the concentrations gradients between different basins. The spreading of CFC plumes in the deep and bottom waters is simulated in a realistic way, and the spatial extent as well as the temporal evolution of these plumes agrees well with observations. Radiocarbon and CFC observations place upper bounds on the northward transports of Antarctic Bottom Water (AABW) into the Pacific, Atlantic, and Indian Oceans. Long-term mean AABW transports larger than 5 Sv (Sv ≡ 106 m3 s−1) through the Vema and Hunter Channels in the South Atlantic and net AABW transports across 30°S into the Indian Ocean larger than 10 Sv are found to be incompatible with CFC data. The rates of equatorward deep and bottom water transports from the North Atlantic and Southern Ocean are of similar magnitude (15.7 Sv at 50°N and 17.9 Sv at 50°S). Deep and bottom water formation in the Southern Ocean occurs at multiple sites around the Antarctic continent and is not confined to the Weddell Sea. A CFC forecast based on the assumption of unchanged abyssal transports shows that by 2030 the entire deep west Atlantic exhibits CFC-11 concentrations larger than 0.1 pmol kg−1, while most of the deep Indian and Pacific Oceans remain CFC free. By 2020 the predicted CFC concentrations in the deep western boundary current (DWBC) in the North Atlantic exceed surface water concentrations and the vertical CFC gradients start to reverse.

scholarly journals The Mean Age of Ocean Waters Inferred from Radiocarbon Observations: Sensitivity to Surface Sources and Accounting for Mixing Histories

2012 ◽  
Vol 42 (2) ◽  
pp. 291-305 ◽  
Author(s):  
Geoffrey Gebbie ◽  
Peter Huybers
Keyword(s):  
North Pacific ◽  
Observational Studies ◽  
Numerical Models ◽  
World Ocean ◽  
Horizontal Resolution ◽  
Global Ocean ◽  
Upper And Lower Bounds ◽  
Potential Range ◽  
The North ◽  
The Mean

Abstract A number of previous observational studies have found that the waters of the deep Pacific Ocean have an age, or elapsed time since contact with the surface, of 700–1000 yr. Numerical models suggest ages twice as old. Here, the authors present an inverse framework to determine the mean age and its upper and lower bounds given Global Ocean Data Analysis Project (GLODAP) radiocarbon observations, and they show that the potential range of ages increases with the number of constituents or sources that are included in the analysis. The inversion requires decomposing the World Ocean into source waters, which is obtained here using the total matrix intercomparison (TMI) method at up to 2° × 2° horizontal resolution with 11 113 surface sources. The authors find that the North Pacific at 2500-m depth can be no younger than 1100 yr old, which is older than some previous observational estimates. Accounting for the broadness of surface regions where waters originate leads to a reservoir-age correction of almost 100 yr smaller than would be estimated with a two or three water-mass decomposition and explains some of the discrepancy with previous observational studies. A best estimate of mean age is also presented using the mixing history along circulation pathways. Subject to the caveats that inference of the mixing history would benefit from further observations and that radiocarbon cannot rule out the presence of extremely old waters from exotic sources, the deep North Pacific waters are 1200–1500 yr old, which is more in line with existing numerical model results.

scholarly journals A global viral oceanography database (gVOD)

2020 ◽  
Author(s):  
Le Xie ◽  
Wei Wei ◽  
Lanlan Cai ◽  
Xiaowei Chen ◽  
Yuhong Huang ◽  
...  
Keyword(s):  
North Atlantic ◽  
Deep Ocean ◽  
Marine Ecology ◽  
Global Ocean ◽  
Viral Production ◽  
Viral Abundance ◽  
The North ◽  
Southeast Pacific ◽  
Order Of Magnitude ◽  
Marine Biosphere

Abstract. Virioplankton is a key component of marine biosphere in maintaining diversity of microorganisms and stabilizing ecosystems. They also greatly contribute to nutrient recycles by releasing organic matter after lysis of hosts. In this study, we constructed the first global viral oceanography database (gVOD) by collecting 10 931 viral abundance (VA) data and 727 viral production (VP) data, along with host and other oceanographic parameters when available. Most VA data were obtained in the North Atlantic (32 %) and North Pacific Oceans (29 %), while the Southeast Pacific and Indian Oceans were quite under sampled. The VA in the global ocean was 1.17 (± 3.31) × 107 particles ml−1. The lytic and lysogenic VP in the global ocean was 9.87 (± 24.16) × 105 and 2.53 (± 8.64) × 105 particles ml−1 h−1, respectively. Average VA in coastal oceans was higher than that in surface open oceans [3.61 (± 6.30) × 107 versus 0.73 (± 1.24) × 107 particles ml−1], while average VP in coastal and surface open oceans was close. Vertically, VA, lytic and lysogenic VP deceased from surface to deep ocean by about one order of magnitude. The total number of viruses in the global ocean estimated by bin average and random forest methods was 1.4 × 1030 particles and 1.39 × 1030 particles, leading to an estimate of global ocean viral biomass at 32.3 and 32.2 Tg C, respectively. We expect that the gVOD will be a fundamental and very useful database for laboratory, field and modeling studies in marine ecology and biogeochemistry. The full gVOD database is stored at PANGAEA (a temporary link: https://www.pangaea.de/tok/19f9d7b496a00f57f491e639440708aee00b6a49).

scholarly journals PRODUCTIVIDAD PRIMARIA EN LAGUNA LARGA, CAYO COCO, CUBA

2011 ◽  
Vol 3 ◽  
pp. 31 ◽  
Author(s):  
Mayrene Guimarais Bermejo ◽  
Roberto González de Zayas
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Net Primary Production ◽  
Ruppia Maritima ◽  
Halodule Wrightii ◽  
Phytoplankton Productivity ◽  
North Central ◽  
Net Production ◽  
The North ◽  
Total Productivity

Se determinó la productividad primaria en Laguna Larga, ubicada en la costa norte y central de Cayo Coco. La producción primaria del fitoplancton y la biomasa del macrofitobentos fueron medidas durante el 2008-2009 en dos sectores de la laguna. La producción primaria neta acuática del sector este fue de 4.32 ± 3.59 g C m-2 día-1 y en el sector oeste fue de 0.71 ± 0.41 g C m-2 día-1. Ambos sectores, atendiendo a la relación producción/respiración anual, fueron autotróficos para el oxígeno e hipertróficos para el carbono. Entre las especies más productivas del macrofitobentos estuvieron: Cladophoropsis sp., Halodule wrightii, Cladophora sp. y Ruppia maritima. La alta producción neta acuática registrada en el sector este, con respecto al oeste, se debe a la contribución del macrofitobentos a la productividad total. El fitoplancton en el sector este exhibió baja productividad (0.12 ± 0.07 g C m-2 día-1) con respecto al oeste (0.71 ± 0.41 g C m-2 día-1), lo que puede deberse a la competencia del macrofitobentos por los nutrientes.ABSTRACT Phytoplankton primary productivity and macrophyte biomass were determined during 2008-2009 for Laguna Larga, located on the north-central coast of Cayo Coco, Cuba. Aquatic net primary production was measured in two different sectors of the lagoon resulting in 4.32 ± 3.59 g C m-2 d-1 and 0.71 ± 0.41 g C m-2 d-1 in the eastern and western part, respectively. In regard to the annual production to respiration ratio, both sections showed autotrophic and hypertrophic levels for the oxygen and carbon metabolisms. The most productive species were Cladophoropsis sp., Halodule wrightii, Cladophora sp. and Ruppia maritima. Aquatic net production recorded for the eastern lobe was higher than the western lobe because of the macrophytobenthos contribution to total productivity. On the contrary, phytoplankton productivity in the eastern part was lower (0.12 ± 0.07 g C m-2 d-1) than the western lobe (0.71 ± 0.41 g C m-2 d-1), probably due to the macrophyte competition for nutrients.

scholarly journals Picophytoplankton biomass distribution in the global ocean

2012 ◽  
Vol 4 (1) ◽  
pp. 37-46 ◽  
Author(s):  
E. T. Buitenhuis ◽  
W. K. W. Li ◽  
D. Vaulot ◽  
M. W. Lomas ◽  
M. R. Landry ◽  
...  
Keyword(s):  
North Atlantic ◽  
World Ocean ◽  
Marine Phytoplankton ◽  
Global Ocean ◽  
Biomass Distribution ◽  
The North ◽  
Carbon Biomass ◽  
The World ◽  
Data Points ◽  
Data Coverage

Abstract. The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1° spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins, and at least some data in all other basins. The average picophytoplankton biomass is 12 ± 22 μg C l−1 or 1.9 g C m−2. We estimate a total global picophytoplankton biomass of 0.53–1.32 Pg C (17–39% Prochlorococcus, 12–15% Synechococcus and 49–69% picoeukaryotes), with an intermediate/best estimate of 0.74 Pg C. Future efforts in this area of research should focus on reporting calibrated cell size and collecting data in undersampled regions. http://doi.pangaea.de/10.1594/PANGAEA.777385

scholarly journals The North Pole Region as an Indicator of the Changing Arctic Ocean: The Need for Sustaining Observations

ARCTIC ◽  
2018 ◽  
Vol 71 (5) ◽  
Author(s):  
James Morison ◽  
Jeremy Wilkinson ◽  
Matthew Alkire ◽  
Frank Nilsen ◽  
Igor Polyakov ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Economies Of Scale ◽  
World Ocean ◽  
North Pole ◽  
The Arctic ◽  
Global Ocean ◽  
The European Union ◽  
International Program ◽  
The North ◽  
The U.S

Sustained observations of environmental conditions in the North Pole region are critical to understanding the changing Arctic Ocean. The Transpolar Drift conduit of sea ice and freshened upper-ocean waters across the Arctic Ocean passes over the North Pole region on its way to the North Atlantic through Fram and Nares Straits. The exported ice and freshened water stratifies the sub-Arctic seas and limits the vertical convection that ventilates the world ocean. Key variables such as ice thickness, bottom pressure, and hydrography in the North Pole region are thus sensitive indicators of changes over the whole Arctic Basin and how these affect the global ocean. Drifting buoys installed in the North Pole region by Great Britain, Canada, France, Germany, Japan, and the U.S. address what would otherwise be a dearth of ocean, ice, and atmosphere observations in the central Arctic. A suite of satellite remote sensing tools such as ICESat/ICESat-2 from the U.S., GRACE from the U.S. and Germany, and CryoSat2 from the European Union extend the conclusions from central Arctic Ocean in situ observations to other regions. Detecting and understanding climate change requires observations over decadal and longer scales. We propose an international program as the key to sustaining these observations in the North Pole region. Such an international program would help immeasurably by 1) facilitating financial sharing of the burden of long-term measurements among several nations, (2) reducing logistics costs through economies of scale, and 3) providing a buffer against national funding, logistics, and geopolitical difficulties.

scholarly journals Picophytoplankton biomass distribution in the global ocean

2012 ◽  
Vol 5 (1) ◽  
pp. 221-242 ◽  
Author(s):  
E. T. Buitenhuis ◽  
W. K. W. Li ◽  
D. Vaulot ◽  
M. W. Lomas ◽  
M. Landry ◽  
...  
Keyword(s):  
North Atlantic ◽  
World Ocean ◽  
Marine Phytoplankton ◽  
Global Ocean ◽  
Biomass Distribution ◽  
The North ◽  
Carbon Biomass ◽  
The World ◽  
Data Points ◽  
Data Coverage

Abstract. The smallest marine phytoplankton, collectively termed picophytoplankton, have been routinely enumerated by flow cytometry since the late 1980s, during cruises throughout most of the world ocean. We compiled a database of 40 946 data points, with separate abundance entries for Prochlorococcus, Synechococcus and picoeukaryotes. We use average conversion factors for each of the three groups to convert the abundance data to carbon biomass. After gridding with 1° spacing, the database covers 2.4% of the ocean surface area, with the best data coverage in the North Atlantic, the South Pacific and North Indian basins. The average picophytoplankton biomass is 12 ± 22 μg C l−1 or 1.9 g C m−2. We estimate a total global picophytoplankton biomass of 0.53–0.74 Pg C (17–39% Prochlorococcus, 12–15% Synechococcus and 49–69% picoeukaryotes). Future efforts in this area of research should focus on reporting calibrated cell size, and collecting data in undersampled regions.

DESIGN AND IMPLEMENTATION OF THE OCEANOGRAPHIC MODELING AND OBSERVATION NETWORK (REMO) FOR PHYSICAL OCEANOGRAPHY STUDIES AND OCEAN FORECASTING

2014 ◽  
Vol 31 (2) ◽  
Author(s):  
Jose Antonio Moreira Lima
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
North Pacific Ocean ◽  
Integrated Approach ◽  
Sea Surface ◽  
Global Ocean ◽  
Height Anomaly ◽  
The North ◽  
Observation Network ◽  
Ocean Forecasting

This paper is concerned with the planning, implementation and some results of the Oceanographic Modeling and Observation Network, named REMO, for Brazilian regional waters. Ocean forecasting has been an important scientific issue over the last decade due to studies related to climate change as well as applications related to short-range oceanic forecasts. The South Atlantic Ocean has a deficit of oceanographic measurements when compared to other ocean basins such as the North Atlantic Ocean and the North Pacific Ocean. It is a challenge to design an ocean forecasting system for a region with poor observational coverage of in-situ data. Fortunately, most ocean forecasting systems heavily rely on the assimilation of surface fields such as sea surface height anomaly (SSHA) or sea surface temperature (SST), acquired by environmental satellites, that can accurately provide information that constrain major surface current systems and their mesoscale activity. An integrated approach is proposed here in which the large scale circulation in the Atlantic Ocean is modeled in a first step, and gradually nested into higher resolution regional models that are able to resolve important processes such as the Brazil Current and associated mesoscale variability, continental shelf waves, local and remote wind forcing, and others. This article presents the overall strategy to develop the models using a network of Brazilian institutions and their related expertise along with international collaboration. This work has some similarity with goals of the international project Global Ocean Data Assimilation Experiment OceanView (GODAE OceanView).

scholarly journals Toward a global reference database of COI barcodes for marine zooplankton

2021 ◽  
Vol 168 (6) ◽  
Author(s):  
Ann Bucklin ◽  
Katja T. C. A. Peijnenburg ◽  
Ksenia N. Kosobokova ◽  
Todd D. O’Brien ◽  
Leocadio Blanco-Bercial ◽  
...  
Keyword(s):  
Species Diversity ◽  
Dna Sequences ◽  
Reference Sequence ◽  
Global Ocean ◽  
Reference Database ◽  
Data Repositories ◽  
Marine Zooplankton ◽  
The North ◽  
Coi Sequences ◽  
Taxonomic Groups

AbstractCharacterization of species diversity of zooplankton is key to understanding, assessing, and predicting the function and future of pelagic ecosystems throughout the global ocean. The marine zooplankton assemblage, including only metazoans, is highly diverse and taxonomically complex, with an estimated ~28,000 species of 41 major taxonomic groups. This review provides a comprehensive summary of DNA sequences for the barcode region of mitochondrial cytochrome oxidase I (COI) for identified specimens. The foundation of this summary is the MetaZooGene Barcode Atlas and Database (MZGdb), a new open-access data and metadata portal that is linked to NCBI GenBank and BOLD data repositories. The MZGdb provides enhanced quality control and tools for assembling COI reference sequence databases that are specific to selected taxonomic groups and/or ocean regions, with associated metadata (e.g., collection georeferencing, verification of species identification, molecular protocols), and tools for statistical analysis, mapping, and visualization. To date, over 150,000 COI sequences for ~ 5600 described species of marine metazoan plankton (including holo- and meroplankton) are available via the MZGdb portal. This review uses the MZGdb as a resource for summaries of COI barcode data and metadata for important taxonomic groups of marine zooplankton and selected regions, including the North Atlantic, Arctic, North Pacific, and Southern Oceans. The MZGdb is designed to provide a foundation for analysis of species diversity of marine zooplankton based on DNA barcoding and metabarcoding for assessment of marine ecosystems and rapid detection of the impacts of climate change.

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