scholarly journals Determination of bacterioplankton biomass, net production and growth efficiency in the Southern Ocean

1991 ◽  
Vol 71 ◽  
pp. 185-194 ◽  
Author(s):  
PK Bjørnsen ◽  
J Kuparinen
Keyword(s):  
Southern Ocean ◽  
Growth Efficiency ◽  
Net Production

Energy Flow and Secondary Production of the Amphipods Hyalella azteca and Crangonyx richmondensis occidentalis in Marion Lake, British Columbia

1971 ◽  
Vol 28 (5) ◽  
pp. 711-726 ◽  
Author(s):  
Jack A. Mathias
Keyword(s):  
Population Growth ◽  
Energy Flow ◽  
Standing Crop ◽  
Production Efficiency ◽  
Hyalella Azteca ◽  
Growth Efficiency ◽  
Ecological Efficiency ◽  
Net Production ◽  
Annual Basis ◽  
Predator System

The Hyalella azteca population in Marion Lake, B.C., assimilated and produced about three times as much energy as did the Crangonyx richmondensis occidentalis population from May 1966 to May 1967, but during the summer the energy flow of H. azteca was four times, and production was five times, that of C. r. occidentalis.Hyalella azteca was abundant at a depth of 1.0 m (mean summer standing crop, 1952 animals/m2), but was rare (75 animals/m2) at depths greater than 2.5 m. Growth, molting, respiration, and hence energy flow rates decreased with depth, due (in part) to lower ambient temperatures in deeper water. On an annual basis, a mean standing crop of 1.1 kcal/m2 of H. azteca assimilated 18.1 kcal/m2, respired 13.5 kcal/m2, and used 4.6 kcal/m2 in production of growth, molts, and eggs. Approximately two-thirds of the annual energy flow was completed between June and October. On an annual basis, the ecological efficiency of an H. azteca-predator system was in the range 2.5–12.5%, the net production efficiency was 25%, and the net population growth efficiency was 16%.The mean summer density of C. r. occidentalis remained constant with depth (about 283 animals/m2). Annual energy flow and production were not appreciably affected by lower temperatures in deeper water. On an annual basis, a mean standing crop of 0.7 kcal/m2 assimilated 6.5 kcal/m2, respired 5.2 kcal/m2, and used 1.4 kcal/m2 in production. Crangonyx r. occidentalis energy flow was fairly constant throughout the year. The ecological efficiency of a C. r. occidentalis-predator system was in the range 2–10.5%, the net production efficiency was 21%, and the population growth efficiency was 17% on an annual basis.

scholarly journals Limitation of Bacterial Growth by Dissolved Organic Matter and Iron in the Southern Ocean

2000 ◽  
Vol 66 (2) ◽  
pp. 455-466 ◽  
Author(s):  
Matthew J. Church ◽  
David A. Hutchins ◽  
Hugh W. Ducklow
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Southern Ocean ◽  
Bacterial Growth ◽  
Bacterial Biomass ◽  
Biomass Accumulation ◽  
Growth Efficiency ◽  
Bacterial Growth Efficiency ◽  
Leucine Incorporation ◽  
Mean Cell Volume

ABSTRACT The importance of resource limitation in controlling bacterial growth in the high-nutrient, low-chlorophyll (HNLC) region of the Southern Ocean was experimentally determined during February and March 1998. Organic- and inorganic-nutrient enrichment experiments were performed between 42°S and 55°S along 141°E. Bacterial abundance, mean cell volume, and [3H]thymidine and [3H]leucine incorporation were measured during 4- to 5-day incubations. Bacterial biomass, production, and rates of growth all responded to organic enrichments in three of the four experiments. These results indicate that bacterial growth was constrained primarily by the availability of dissolved organic matter. Bacterial growth in the subtropical front, subantarctic zone, and subantarctic front responded most favorably to additions of dissolved free amino acids or glucose plus ammonium. Bacterial growth in these regions may be limited by input of both organic matter and reduced nitrogen. Unlike similar experimental results in other HNLC regions (subarctic and equatorial Pacific), growth stimulation of bacteria in the Southern Ocean resulted in significant biomass accumulation, apparently by stimulating bacterial growth in excess of removal processes. Bacterial growth was relatively unchanged by additions of iron alone; however, additions of glucose plus iron resulted in substantial increases in rates of bacterial growth and biomass accumulation. These results imply that bacterial growth efficiency and nitrogen utilization may be partly constrained by iron availability in the HNLC Southern Ocean.

Viral effects on bacterial respiration, production and growth efficiency: Consistent trends in the Southern Ocean and the Mediterranean Sea

2008 ◽  
Vol 55 (5-7) ◽  
pp. 790-800 ◽  
Author(s):  
Osana Bonilla-Findji ◽  
Andrea Malits ◽  
Dominique Lefèvre ◽  
Emma Rochelle-Newall ◽  
Rodolphe Lemée ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Mediterranean Sea ◽  
Growth Efficiency ◽  
Bacterial Respiration ◽  
The Mediterranean

scholarly journals Oxygen in the Southern Ocean From Argo Floats: Determination of Processes Driving Air-Sea Fluxes

2017 ◽  
Vol 122 (11) ◽  
pp. 8661-8682 ◽  
Author(s):  
Seth M. Bushinsky ◽  
Alison R. Gray ◽  
Kenneth S. Johnson ◽  
Jorge L. Sarmiento
Keyword(s):  
Southern Ocean ◽  
Argo Floats

Specific features of determination of the net production of nitrous oxide by soils

2015 ◽  
Vol 48 (6) ◽  
pp. 608-619 ◽  
Author(s):  
N. D. Ananyeva ◽  
K. V. Ivashchenko ◽  
E. V. Stolnikova ◽  
A. L. Stepanov ◽  
V. N. Kudeyarov
Keyword(s):  
Nitrous Oxide ◽  
Net Production

scholarly journals Consequences of respiration in the light on the determination of production in pelagic systems

2006 ◽  
Vol 3 (5) ◽  
pp. 1367-1389 ◽  
Author(s):  
O. Pringault ◽  
V. Tassas ◽  
E. Rochelle-Newall
Keyword(s):  
Carbon Cycle ◽  
Water Samples ◽  
Sea Water ◽  
Dark Respiration ◽  
Metabolic Balance ◽  
Net Production ◽  
Respiration Rates ◽  
Reproducible Technique ◽  
Coastal Sea

Abstract. Oxygen microprobes were used to estimate Respiration (R), Net Production (NP) and Production (P) in coastal sea water samples. Using this highly stable and reproducible technique to measure oxygen change during alternating dark and light periods, we show that respiration in the light could represent up to 640% of respiration in the dark. This light enhanced dark respiration can remain elevated for several hours following a 12 h period of illumination. The non inclusion of Rlight into calculations of production leads to an underestimation of P, which can reach up to 650% in net heterotrophic systems. The P:R ratio is in turn affected by the higher respiration rates and by the underestimation of P. While the integration of Rlight in to the calculation of P:R ratio does not change the metabolic balance of the system, it decreases the observed tendency, thus net autotrophic systems become less autotrophic and net heterotrophic systems become less heterotrophic. As a consequence, we propose that efforts have to be focused on the estimation and the integration of Rlight into the determination of P and R for a better understanding of the aquatic carbon cycle.

The Southern Ocean Waves Experiment. Part III: Sea Surface Slope Statistics and Near-Nadir Remote Sensing

2008 ◽  
Vol 38 (3) ◽  
pp. 670-685 ◽  
Author(s):  
E. J. Walsh ◽  
C. W. Wright ◽  
M. L. Banner ◽  
D. C. Vandemark ◽  
B. Chapron ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Incidence Angle ◽  
Wave Spectrum ◽  
Ocean Waves ◽  
Sea Surface ◽  
Radar Altimeter ◽  
Ka Band ◽  
Wide Range ◽  
Non Gaussian

Abstract During the Southern Ocean Waves Experiment (SOWEX), registered ocean wave topography and backscattered power data at Ka band (36 GHz) were collected with the NASA Scanning Radar Altimeter (SRA) off the coast of Tasmania under a wide range of wind and sea conditions, from quiescent to gale-force winds with 9-m significant wave height. Collection altitude varied from 35 m to over 1 km, allowing determination of the sea surface mean square slope (mss), the directional wave spectrum, and the detailed variation of backscattered power with incidence angle, which deviated from a simple Gaussian scattering model. The non-Gaussian characteristics of the backscatter increased systematically with the mss, suggesting that a global model to characterize Ka-band radar backscatter from the sea surface within 25° of nadir might be possible.

scholarly journals The determination of sea level in the Southern Ocean

1985 ◽  
Vol 4 (1) ◽  
pp. 29-34 ◽  
Author(s):  
J. R. E. Lutjeharms
Keyword(s):  
Southern Ocean ◽  
Sea Level ◽  
Research Projects ◽  
Specific Research

The importance of sea-level measurements for an understanding both of oceanology and of climate is increasingly stressed in the literature. This review of existing knowledge on the sea-level of the Southern Ocean reveals certain well-defined gaps and it points to a need for specific research projects to fill these gaps.

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