Microbes in antarctic waters of the Drake Passage: Vertical patterns of substrate uptake, productivity and biomass in January 1980

Polar Biology ◽  
1983 ◽  
Vol 2 (3) ◽  
pp. 179-188 ◽  
Author(s):  
R. B. Hanson ◽  
H. K. Lowery ◽  
D. Shafer ◽  
R. Sorocco ◽  
D. H. Pope
Keyword(s):  
Drake Passage ◽  
Substrate Uptake ◽  
Antarctic Waters

In situ evidence for a nutrient limitation of phytoplankton growth in pelagic Antarctic waters

1994 ◽  
Vol 6 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Osmund Holm-Hansen ◽  
Anthony F. Amos ◽  
Nelson Silva S. ◽  
Virginia Villafañe ◽  
E. Walter Helbling
Keyword(s):  
Nutrient Limitation ◽  
Surface Waters ◽  
Phytoplankton Biomass ◽  
Drake Passage ◽  
Nutrient Concentrations ◽  
Ancillary Data ◽  
Water Types ◽  
Antarctic Waters ◽  
Subsurface Maximum

Studies in a large (30000 km2) sampling grid around Elephant Island, Antarctica, during January–March of four successive years (1990–1993) have shown that one of the water types within the sampling area (Drake Passage water) shows low chlorophyll a in surface waters and a subsurface maximum between 50 and 80 m depth. Ancillary data (beam attenuation, in situ chl a fluorescence) support the view that the extracted chl a values actually do represent increased phytoplankton biomass at depth; other data (oxygen concentrations and upwelling radiance at 683 nm) suggest that the phytoplankton within this subsurface maximum layer are photosynthetically active and do not represent a senescent, sinking population of cells. Such deep chl a maxima were found only in Drake Passage waters; in the other four water types sampled, chl a concentrations were maximal in surface waters and decreased with depth. Phytoplankton biomass and activity in Drake Passage waters is suggestive of a nutrient limitation for phytolankton growth in surface waters. Nutrient concentrations of N, P, and Si were high throughout the euphotic zone at all stations, and hence it is unlikely that any macronutrient would be limiting. The data presented in this paper support the hypothesis of Martin and colleagues that availability of Fe may limit phytoplankton biomass in pelagic Antarctic waters, but not in coastal waters where Fe concentrations are relatively high. All other reports on the effects of Fe on Antarctic phytoplankton have utilized deck incubations from which it is difficult to extrapolate such evidence of nutrient limitation to in situ conditions. Our data represent the first in situ evidence linking Fe limitation to the paradox of high macronutrient concentrations and low phytoplankton biomass in Antarctic pelagic waters.

Quaternary colonization or Paleogene persistence?: historical biogeography of skates (Chondrichthyes: Rajidae) in the Antarctic ichthyofauna

Paleobiology ◽  
1994 ◽  
Vol 20 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Douglas J. Long
Keyword(s):  
Western Europe ◽  
Middle Eocene ◽  
Habitat Preferences ◽  
Drake Passage ◽  
The Arctic ◽  
Western Atlantic ◽  
Western Tethys ◽  
Antarctic Waters ◽  
La Meseta Formation ◽  
Dispersal Corridor

Seven endemic species of skates (Chondrichthyes: Rajidae) represent the only family of elasmobranchs currently known to live in Antarctic continental waters. Many previous authors believed skates colonized Antarctic waters from Patagonia during interglacial periods in the Quaternary. However, recent fossil material collected from the middle Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula, indicates that they may have persisted in Antarctic waters since the Paleogene. Additionally, oceanographic barriers present in the Neogene and Quaternary would have prevented dispersal from southern continents to Antarctica. A revised dispersal scenario, based on skate fossils, biology, paleogeography, and present centers of skate diversity, suggests that skates evolved in the western Tethys and North Boreal seas of western Europe in the Late Cretaceous and early Paleogene and emigrated into Antarctica during the early to middle Eocene via a dispersal corridor along the continental margins of the western Atlantic Ocean. Skates probably populated the Pacific Basin by passing from this dispersal corridor through the Arctic Ocean. Vicariant events, such as opening of the Drake Passage, the development of the Circum-Antarctic Current, and formation of deep and wide basins around Antarctica in the late Paleogene, created barriers that isolated some species of skates in Antarctica and prevented movement of other species of skates into Antarctica from northern areas. Skates are the only group of fishes known to have survived the Oligocene cooling of Antarctica that killed or extirpated the Paleogene ichthyofauna; they persisted by a combination of cold-tolerance, generalized diet, and unspecialized bathymetric and habitat preferences.

Diatom Fouling of the Little Picked Whales in the Antarctic Waters

2012 ◽  
Vol 48 (1) ◽  
pp. 28-34 ◽  
Author(s):  
V. L. Zinchenko ◽  
V. P. Gerasimyuk
Keyword(s):  
Antarctic Waters ◽  
The Antarctic

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

Dynamics of phosphorus and organic substrates in anaerobic and aerobic phases of a sequencing batch reactor

1994 ◽  
Vol 30 (6) ◽  
pp. 237-246 ◽  
Author(s):  
A. Carucci ◽  
M. Majone ◽  
R. Ramadori ◽  
S. Rossetti
Keyword(s):  
Sequencing Batch Reactor ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
General Assumption ◽  
Organic Substrate ◽  
Operating Conditions ◽  
Phosphate Removal ◽  
Substrate Uptake ◽  
Organic Substrates ◽  
Polyphosphate Metabolism

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch reactor (SBR). The synthetic feed used was based on peptone and glucose as organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991). The experimental work was divided into two runs, each characterized by different operating conditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulating and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called “G bacteria”. The results obtained seem to be inconsistent with the general assumption that the G bacteria are characterized by anaerobic substrate uptake not connected with any polyphosphate metabolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as organic substrates show that the role of acetate in the biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.

Phosphorus Release Kinetics in Biofilm Reactors

1992 ◽  
Vol 26 (3-4) ◽  
pp. 567-576 ◽  
Author(s):  
F. A. Ruiz-Treviño ◽  
S. González-Martínez ◽  
C. Doria-Serrano ◽  
M. Hernández-Esparza
Keyword(s):  
Phosphorus Removal ◽  
Release Kinetics ◽  
Phosphorus Release ◽  
Organic Substrate ◽  
Biofilm Reactor ◽  
Substrate Uptake ◽  
Biofilm Reactors ◽  
Initial Substrate ◽  
Linear Behaviour ◽  
Substrate Concentrations

This paper presents the kinetic analysis, using Generalized Power-Law equations to describe the results of an experimental investigation conducted on a batch submerged biofilm reactor for phosphorus removal under an anaerobic/aerobic cycle. The observed rates and amounts of phosphorus release and organic substrate uptake in the anaerobic phase leads to a kinetic model in which these two variables are dependent on each other with a non-linear behaviour and reach equilibrium values in both cases, at different times and are function of rate constants ratio. The model has a good fit with experimental data except for C uptake at anaerobic contact times longer than four hours, where other kinetics are implied. Kinetic parameters were obtained with different initial substrate concentrations, anaerobic contact cycles, and type of substrates.

Antarctic Peninsula sea levels: a real-time system for monitoring Drake Passage transport

2006 ◽  
Vol 18 (3) ◽  
pp. 429-436 ◽  
Author(s):  
P.L. Woodworth ◽  
C.W. Hughes ◽  
D.L. Blackman ◽  
V.N. Stepanov ◽  
S.J. Holgate ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Real Time ◽  
Antarctic Peninsula ◽  
Tide Gauge ◽  
Drake Passage ◽  
Southern Annular Mode ◽  
Time System ◽  
International Polar Year ◽  
Real Time System ◽  
Sea Levels

Sub-surface pressure (SSP) data from tide gauges at three bases on the Pacific coast of the Antarctic Peninsula, together with SSP information from a bottom pressure recorder deployed on the south side of the Drake Passage, have been used to study the relationships between SSP, Drake Passage transport, and the strength of Southern Ocean zonal winds as represented by the Southern Annular Mode. High correlations were obtained between all parameters, confirming results obtained previously with independent data sets, and demonstrating the value of information from the permanent Rothera base, the southern-most site considered. These are important findings with regard to the design, installation and maintenance of observation networks in Antarctica. In particular, they provide the necessary justification for Antarctic Peninsula tide gauge infrastructure investment in the lead up to International Polar Year. Data delivery from Rothera and Vernadsky is currently being improved and should soon enable the first near real-time system for monitoring Drake Passage transport variability on intraseasonal timescales, an essential component of a Southern Ocean Observing System.

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