scholarly journals Ecophysiology of a common unannotated gene transcript in surface water microbial assemblages of the oligotrophic open ocean

2010 ◽  
Vol 60 (3) ◽  
pp. 289-297
Author(s):  
JM Brown ◽  
I Hewson
Keyword(s):  
Surface Water ◽  
Open Ocean ◽  
Gene Transcript ◽  
Unannotated Gene

scholarly journals Carbon dynamics and CO<sub>2</sub> air-sea exchanges in the eutrophied coastal waters of the Southern Bight of the North Sea: a modelling study

2004 ◽  
Vol 1 (2) ◽  
pp. 147-157 ◽  
Author(s):  
N. Gypens ◽  
C. Lancelot ◽  
A. V. Borges
Keyword(s):  
Surface Water ◽  
Coastal Zone ◽  
North Sea ◽  
Coastal Waters ◽  
Co2 Flux ◽  
Open Ocean ◽  
Atmospheric Co2 ◽  
Southern Bight ◽  
The North ◽  
The North Sea

Abstract. A description of the carbonate system has been incorporated in the MIRO biogeochemical model to investigate the contribution of diatom and Phaeocystis blooms to the seasonal dynamics of air-sea CO2 exchanges in the Eastern Channel and Southern Bight of the North Sea, with focus on the eutrophied Belgian coastal waters. For this application, the model was implemented in a simplified three-box representation of the hydrodynamics with the open ocean boundary box ‘Western English Channel’ (WCH) and the ‘French Coastal Zone’ (FCZ) and ‘Belgian Coastal Zone’ (BCZ) boxes receiving carbon and nutrients from the rivers Seine and Scheldt, respectively. Results were obtained by running the model for the 1996–1999 period. The simulated partial pressures of CO2 (pCO2) were successfully compared with data recorded over the same period in the central BCZ at station 330 (51°26.05′ N; 002°48.50′ E). Budget calculations based on model simulations of carbon flow rates indicated for BCZ a low annual sink of atmospheric CO2 (−0.17 mol C m-2 y-1). On the opposite, surface water pCO2 in WCH was estimated to be at annual equilibrium with respect to atmospheric CO2. The relative contribution of biological, chemical and physical processes to the modelled seasonal variability of pCO2 in BCZ was further explored by running model scenarios with separate closures of biological activities and/or river inputs of carbon. The suppression of biological processes reversed direction of the CO2 flux in BCZ that became, on an annual scale, a significant source for atmospheric CO2 (+0.53 mol C m-2 y-1). Overall biological activity had a stronger influence on the modelled seasonal cycle of pCO2 than temperature. Especially Phaeocystis colonies which growth in spring were associated with an important sink of atmospheric CO2 that counteracted the temperature-driven increase of pCO2 at this period of the year. However, river inputs of organic and inorganic carbon were shown to increase the surface water pCO2 and hence the emission of CO2 to the atmosphere. Same calculations conducted in WCH, showed that temperature was the main factor controlling the seasonal pCO2 cycle in these open ocean waters. The effect of interannual variations of fresh water discharge (and related nutrient and carbon inputs), temperature and wind speed was further explored by running scenarios with forcing typical of two contrasted years (1996 and 1999). Based on these simulations, the model predicts significant variations in the intensity and direction of the annual air-sea CO2 flux.

Per- and polyfluoroalkyl substances in surface water, gas and particle in open ocean and coastal environment

Chemosphere ◽  
2021 ◽  
Vol 272 ◽  
pp. 129869
Author(s):  
Eriko Yamazaki ◽  
Sachi Taniyasu ◽  
Xinhong Wang ◽  
Nobuyoshi Yamashita
Keyword(s):  
Surface Water ◽  
Coastal Environment ◽  
Open Ocean ◽  
Polyfluoroalkyl Substances ◽  
Water Gas

scholarly journals Tidal mixing of estuarine and coastal waters in the Western English Channel controls spatial and temporal variability in seawater CO<sub>2</sub>

2021 ◽  
Author(s):  
Richard Peter Sims ◽  
Michael Bedington ◽  
Ute Schuster ◽  
Andrew Watson ◽  
Vassilis Kitidis ◽  
...  
Keyword(s):  
Surface Water ◽  
Coastal Waters ◽  
Tidal Cycle ◽  
Co2 Flux ◽  
Open Ocean ◽  
Tidal Mixing ◽  
Spatial And Temporal Variability ◽  
Spatial And Temporal Patterns ◽  
Surface Salinity ◽  
Estuarine Coastal

Abstract. Surface ocean CO2 measurements are used to compute the oceanic air–sea CO2 flux. The CO2 flux component from rivers and estuaries is uncertain. Estuarine and coastal water carbon dioxide (CO2) observations are relatively few compared to observations in the open ocean. The contribution of these regions to the global air–sea CO2 flux remains uncertain due to systematic under-sampling. Existing high-quality CO2 instrumentation predominantly utilise showerhead and percolating style equilibrators optimised for open ocean observations. The intervals between measurements made with such instrumentation make it difficult to resolve the fine-scale spatial variability of surface water CO2 at timescales relevant to the high frequency variability in estuarine and coastal environments. Here we present a novel dataset with unprecedented frequency and spatial resolution transects made at the Western Channel Observatory in the south west of the UK from June to September 2016, using a fast response seawater CO2 system. Novel observations were made along the estuarine–coastal continuum at different stages of the tide and reveal distinct spatial patterns in the surface water CO2 fugacity (fCO2) at different stages of the tidal cycle. Changes in salinity and fCO2 were closely correlated at all stages of the tidal cycle and suggest that the mixing of oceanic and riverine end members determines the variations in fCO2. The observations demonstrate the complex dynamics determining spatial and temporal patterns of salinity and fCO2 in the region. Spatial variations in observed surface salinity were used to validate the output of a regional high resolution hydrodynamic model. The model enables a novel estimate of the air–sea CO2 flux in the estuarine–coastal zone. Air–sea CO2 flux variability in the estuarine–coastal boundary region is dominated by the state of the tide because of strong CO2 outgassing from the river plume. The observations and model output demonstrate that undersampling the complex tidal and mixing processes characteristic of estuarine and coastal environment bias quantification of air-sea CO2 fluxes in coastal waters. The results provide a mechanism to support critical national and regional policy implementation by reducing uncertainty in carbon budgets.

scholarly journals EXCITATION OF WAVES INSIDE A BOTTOMLESS HARBOR

1972 ◽  
Vol 1 (13) ◽  
pp. 110 ◽  
Author(s):  
Noboru Sakuma ◽  
Johannes Buhler ◽  
R.L. Wiegel
Keyword(s):  
Surface Water ◽  
Water Waves ◽  
Theoretical Study ◽  
Open Ocean ◽  
Sea Surface ◽  
Sea Floor ◽  
Surface Water Waves

In planning enclosed areas in the ocean, such as offshore harbors for fishing or recreational boats, one has to consider very carefully the problem of forced seiches due to surface water waves. A number of papers have been written on this problem> but to the authors' knowledge, only one of them has treated the case of an artificial bottomless circular harbor in the open ocean, for which the walls extend only part way to the sea floor. A bottom to such a harbor, which would be expensive, can only be omitted if the effect of its absence on the sea surface inside the harbor is not overly detrimental. C.J.R. Garrett (1970) made a theoretical study of the excitation of waves inside such a harbor for the 'no-entrance' case. The object of this caper is to evaluate experimentally the behavior of the sea surface inside such a harbor, to compare the results with the theoretical values obtained by Garrett, and to extend the observations to the case for which there is an entrance to the harbor.

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

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