Biophysics of the Surface Microlayer of Aquatic Ecosystems

2015 ◽  
Vol 4 (0) ◽  
pp. 9781780403007-9781780403007 ◽  
Author(s):  
M. Gladyshev
Keyword(s):  
Aquatic Ecosystems ◽  
Surface Microlayer

Environmental Assessment of Tributyltin in Canada

1992 ◽  
Vol 25 (11) ◽  
pp. 125-132 ◽  
Author(s):  
R. J. Maguire
Keyword(s):  
Fresh Water ◽  
Aquatic Ecosystems ◽  
Degradation Products ◽  
Subsurface Water ◽  
Surface Microlayer ◽  
Biological Degradation ◽  
Sensitive Species ◽  
Water And Sediment ◽  
Antifouling Agent ◽  
Shipping Traffic

The aquatic chemistry, fate and toxicity of tributyltin are reviewed. A summary is given of investigations of the occurrence and persistence of tributyltin and its less toxic degradation products in water and sediment in Canada. Tributyltin was mainly found in areas of heavy boating or shipping traffic, which was consistent with its use as an antifouling agent. In about 8% of the 269 locations across Canada at which samples were collected, tributyltin was found in water at concentrations which could cause chronic toxicity in a sensitive species, rainbow trout. Tributyltin was occasionally found in the surface microlayer of fresh water at much higher concentrations than in subsurface water. It was also found in about 30% of sediment samples collected across Canada. The few fish analyzed that contained tributyltin were from harbours, a finding consistent with findings in water and sediment. Biological degradation in water and sediment appears to be the most important factor limiting the persistence of tributyltin in aquatic ecosystems. Estimates of the half-life of biological degradation of tributyltin in fresh water and sediment in Canada are in the range of a few weeks to 4-5 months, respectively. Recent Canadian regulations of tributyltin are discussed as well as the current Canadian Environmental Protection Act review of non-pesticidal organotins.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

Sanitary-Hydrobiological Characteristics of Aquatic Ecosystems in terms of Microphytobenthos

2011 ◽  
Vol 47 (6) ◽  
pp. 63-74
Author(s):  
O. P. Oksiyuk ◽  
O. A. Davydov
Keyword(s):  
Aquatic Ecosystems

Use of the Indices of Macrozoobenthos Diversity as Indicators of the State of Aquatic Ecosystems

2003 ◽  
Vol 39 (4) ◽  
pp. 16-25 ◽  
Author(s):  
A. V. Lyashenko ◽  
A. A. Protasov
Keyword(s):  
Aquatic Ecosystems ◽  
The State

Extracellular enzymatic activities in the aquatic ecosystems of the Danube Delta. 2. Alkaline phosphatase activity

2021 ◽  
Vol 26 (1) ◽  
pp. 2269-2274
Author(s):  
IOAN PĂCEŞILĂ ◽  
EMILIA RADU
Keyword(s):  
Alkaline Phosphatase ◽  
Water Column ◽  
Aquatic Ecosystems ◽  
Temporal Dynamics ◽  
Extracellular Enzyme ◽  
Danube Delta ◽  
Phytoplankton Communities ◽  
Extracellular Enzymatic Activities ◽  
Adjacent Channels ◽  
Hydrolysis Of

Phosphorus is one of the most important inorganic nutrients in aquatic ecosystems, the development and functioning of the phytoplankton communities being often correlated with the degree of availability in assimilable forms of this element. Alkaline phosphatase (AP) is an extracellular enzyme with nonspecific activity that catalyses the hydrolysis of a large variety of organic phosphate esters and release orthophosphates. During 2011-2013, AP Activity (APA) was assessed in the water column and sediments of several aquatic ecosystems from Danube Delta: Roșu Lake, Mândra Lake and their adjacent channels – Roșu-Împuțita and Roșu-Puiu. The intensity of APA widely fluctuated, ranging between 230-2578 nmol p-nitrophenol L-1h-1 in the water column and 2104-15631 nmol p-nitrophenol g-1h-1 in sediment. Along the entire period of the study, APA was the most intense in Roșu-Împuțita channel, for both water and sediment samples. Temporal dynamics revealed its highest values in summer for the water column and in autumn for sediment. Statistical analysis showed significant seasonal diferences of the APA dynamics in spring vs. summer and autumn for the water column, and any relevant diferences for sediment.

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