scholarly journals Spatio-temporal variation in number and production of neustonic and planktonic bacteria inhabiting polluted estuarine harbour channel

2021 ◽  
Vol 203 (9) ◽  
pp. 5547-5559
Author(s):  
Piotr Perliński ◽  
Zbigniew J. Mudryk ◽  
Marta Zdanowicz ◽  
Łukasz Kubera
Keyword(s):  
Seasonal Variation ◽  
Secondary Production ◽  
Seasonal Cycle ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Water Basin ◽  
Planktonic Bacteria ◽  
Microbiological Parameters ◽  
Spatio Temporal ◽  
Number Of Bacteria

AbstractThe aim of this paper was to determine the abundance and secondary production by bacteria inhabiting the surface microlayer and subsurface water in a specific water basin, i.e., polluted estuarine harbour channel. In a 3-year seasonal cycle, the total number of bacteria and their biomass were higher in the surface microlayer (SML) 7.57 × 108cells dm−3 and 15.86 µg C dm−3 than in the subsurface water (SSW) 4.25 × 108cells dm−3 and 9.11 µg C dm−3 of the studied channel. The opposite relationship was noted in the level of the secondary production (SML—37.16 μg C dm−3 h−1, SSW—60.26 μg C dm−3 h−1) in this water basin. According to the analysed microbiological parameters, the total number of bacteria and secondary production varied along the horizontal profile in the water of the studied channel. The total number of bacteria and their secondary production showed the seasonal variation as well.

scholarly journals Surfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tank

2016 ◽  
Author(s):  
R. Pereira ◽  
K. Schneider-Zapp ◽  
R. C. Upstill-Goddard
Keyword(s):  
Gas Exchange ◽  
Coastal Waters ◽  
Enrichment Factors ◽  
Subsurface Water ◽  
Gas Transfer ◽  
Surface Microlayer ◽  
Transfer Velocity ◽  
Gas Transfer Velocity ◽  
North East ◽  
Spatio Temporal

Abstract. We measured total surfactant activity (SA; Triton T-X-100 equivalent) and CDOM absorbance (cm-1) in the surface microlayer (SML) and subsurface water (SSW) seasonally (2012-2013) along a 20 km coastal transect (North East UK), and evaluated corresponding values of the gas transfer velocity (kw; cm hr-1) using a custom designed air-sea gas exchange tank. Spatial SA variability exceeded its temporal variability. Overall, SA varied five-fold between all samples (0.08 - 0.38 mg L-1 T-X-100), being highest in the SML during summer. SML SA enrichment factors relative to SSW were ~ 1.0 - 1.9, except for two values (0.75; 0.89: February 2013). CDOM absorbance (250 - 450 nm), the CDOM spectral slope ratio (SR = S275–295 / S350–400) and the 250:365 nm CDOM absorbance ratio (E2 : E3) demonstrate the potential for terrestrially-derived CDOM to be biogeochemically processed in North Sea coastal waters. The range in corresponding k660 (kw for CO2; freshwater; 20 °C) was 6.8 - 22.0 cm hr-1. The film factor R660 (the ratio of the scaled transfer velocity k660 to the one of clean water) strongly correlates with SA (r ≥0.70, p ≤0.002, each n = 16) with high SML SA correlated to k660 suppression ~14 - 51 % relative to clean laboratory water, highlighting strong spatio-temporal gradients in gas exchange due to varying surfactant in these coastal waters. Such variability should be taken account of when evaluating marine trace gas sources and sinks.

Comparison of the water quality of the surface microlayer and subsurface water in the Guangzhou segment of the Pearl River, China

2014 ◽  
Vol 24 (3) ◽  
pp. 475-491 ◽  
Author(s):  
Qing Liu ◽  
Xiaojuan Hu ◽  
Jiangluan Jiang ◽  
Junyi Zhang ◽  
Zhihui Wu ◽  
...  
Keyword(s):  
Water Quality ◽  
Subsurface Water ◽  
Pearl River ◽  
Surface Microlayer ◽  
The Pearl River

scholarly journals Seasonal variation in surface-subsurface water exchange and lateral hyporheic area of two stream-aquifer systems

1998 ◽  
Vol 34 (3) ◽  
pp. 317-328 ◽  
Author(s):  
Gregory J. Wroblicky ◽  
Michael E. Campana ◽  
H. Maurice Valett ◽  
Clifford N. Dahm
Keyword(s):  
Seasonal Variation ◽  
Water Exchange ◽  
Subsurface Water ◽  
Aquifer Systems

Microbiological and chemical enrichment of freshwater-surface microlayers relative to the bulk-subsurface water

1974 ◽  
Vol 20 (7) ◽  
pp. 1051-1057 ◽  
Author(s):  
Roger F. Hatcher ◽  
Bruce C. Parker
Keyword(s):  
Ammonium Nitrate ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Ecological Functions ◽  
Chemical Enrichment

Concentrations of bacteria, fungi, ammonium, nitrate, nitrite, orthophosphate, sulfate, and certain metals were enriched in freshwater-surface microlayer samples relative to the bulk-subsurface water. Results differed markedly depending on which of three methods for surface-microlayer collection was used. This report suggests that the biologically and chemically rich freshwater-surface microlayers contribute to ecological functions and interactions between subsurface water and the atmosphere not heretofore investigated in freshwater.

scholarly journals Foraging theory upscaled: the behavioural ecology of herbivore movement

2010 ◽  
Vol 365 (1550) ◽  
pp. 2267-2278 ◽  
Author(s):  
N. Owen-Smith ◽  
J. M. Fryxell ◽  
E. H. Merrill
Keyword(s):  
Seasonal Cycle ◽  
Large Scale ◽  
Diel Activity ◽  
Patch Selection ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Gps Collars ◽  
Activity Schedule ◽  
Spatio Temporal ◽  
Time And Energy

We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.

Chlorinated Hydrocarbons in the Surface Microlayer and Subsurface Water of the Niagara River, 1985-86

1988 ◽  
Vol 23 (2) ◽  
pp. 292-300 ◽  
Author(s):  
R. James Maguire ◽  
Richard J. Tkacz
Keyword(s):  
Chlorinated Hydrocarbons ◽  
Lake Ontario ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Water Interface ◽  
Niagara River ◽  
Niagara Falls ◽  
Increased Risk ◽  
Air Water Interface ◽  
High Concentrations

Abstract The surface microlayer of the Niagara River at Niagara-on-the-Lake was sampled 34 times in 1985-86, and was shown to contain PCBs, chlorobenzenes and chlorinated hydrocarbons at concentrations generally up to 40 times greater than concentrations 1n subsurface water. Organisms which spend part or all of their lives at the air-water interface are thus likely to be at increased risk relative to subsurface water exposure. A small “spill” of PCBs 1n the river on July 29, 1986 was only detected in the surface micro-layer, and not in subsurface water. On this date, concentrations of PCBs in the surface microlayer were up to 6,400 times larger than concentrations in the subsurface water, and 1t appeared that the “spill” was downstream of Niagara Falls and the Whirlpool. Despite such high concentrations of chlorinated hydrocarbons in the surface microlayer, at no time during this study did the microlayer contribute significantly, relative to subsurface water, to the loading (i.e., amounts) of these chemicals from the Niagara River to Lake Ontario.

An investigation of the role of thyroid hormones in the control of secondary fibre growth and moult in cashmere goats

1995 ◽  
Vol 1995 ◽  
pp. 104-104
Author(s):  
S.M. Rhind ◽  
S.R. McMillen
Keyword(s):  
Seasonal Variation ◽  
Thyroid Hormones ◽  
Hair Follicle ◽  
Seasonal Cycle ◽  
Reproductive Activity ◽  
Direct Role ◽  
Fibre Growth ◽  
Cashmere Goats ◽  
Secondary Fibre

The growth of a fine undercoat (cashmere) in goats is a seasonal phenomenon; growth generally begins during the autumn, continues into the winter and is followed by a moult in the spring. The endocrine mechanisms involved in the control of these processes are unclear but the thyroid hormones have been implicated in the control of fibre growth (Ferguson, Schenckel, Carter and Clarke, 1956; Lincoln, Klandorf and Anderson, 1980) and in the normal seasonal cycle of reproductive activity in sheep (Follett and Potts, 1990). However, it is not known whether or not the thyroid hormones have a role in the mediation of photoperiodic effects on secondary hair follicle activity in goats.Most of the metabolic activity of the thyroid hormones is thought to be attributable to triiodothyronine (T3) which is primarily derived from thyroxine (T4) by a process of monodeiodination. This process can be inhibited by treatment with methylthiouracil.The aim of this study was to suppress the synthesis of T3 and so to determine whether or not it has a direct role in the control of seasonal variation of secondary hair follicle activity and cashmere growth and moulting.

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