| 1. |
|
|
| 2. |
- Gilbert, F., et al.
(författare)
-
2-D optical quantification of particle reworking activities in marine surface sediments
- 2003
-
Ingår i: JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY. - 0022-0981. ; 285, s. 251-263
-
Tidskriftsartikel (refereegranskat)abstract
- Particle and solute transport by faunal activities may significantly influence rates and pathways of organic matter mineralization during early diagenesis in surface sediments. One of the most frequently utilized techniques to quantify benthic biological reworking activities involves the calculation of a biodiffusion coefficient (D-b) estimated from model predictions of 1-D tracer distribution patterns. This technique is labor-intensive and time-demanding. Furthermore, it is normally used for measurements over several days and averages overall transport mechanisms from 3-D to 1-D on a cm scale. In the frame of this work, we developed a new technique based on the nondestructive screening of fluorescent particles (luminophores) using optical discrimination and CCD camera detection of fluorescence (2-D). At a site characterized by a dense population of the brittle star Amphiura filiformis and a high biodiffusion coefficient (obtained from 1-D distributions; D-b = 3 5.5 +/- 3.7 cm(-2) year(-1); n = 3), the optical reworking coefficient (ORC), estimated from the 2-D luminophore distribution patterns, was calculated (ORC = 27.4 +/- 9.1 DeltaQ cm(-2) h(-1); n=24). A nondestructive 2-D approach to quantify particle reworking may provide a powerful and complementary tool to further understand particle transport by the benthic fauna in surface sediments. The optical technique for 2-D detection of luminophores is relatively fast and easy to perform, with the ability to detect small scale (mm) particle movements on a time resolution of minutes or less. (C) 2002 Elsevier Science B.V. All rights reserved.
|
|
| 3. |
|
|
| 4. |
- Gilbert, F., et al.
(författare)
-
Sediment reworking by marine benthic species from the Gullmar Fjord (Western Sweden): Importance of faunal biovolume
- 2007
-
Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 348:1-2, s. 133-144
-
Tidskriftsartikel (refereegranskat)abstract
- In order to compare and quantify sediment reworking activities by different species/functional groups of macrofauna, a laboratory experiment was carried out with species from the Gullmarsfjord (Western Sweden). Monospecific communities of Amphiura filiformis, Echinocardium cordatum, Scalibregma inflatum and Abra nitida were introduced in experimental mesocosms, with identical densities (795 ind. m(-2)), for 10 days. Sediment reworking was studied by quantifying downward and upward movements of fluorescent inert tracers (luminophores). Luminophores with different colour were initially deposited both at the sediment surface and within the sediments. Population biomass and biovolume were also determined. Surface tracers reworking coefficients ranged from 0.6 to 2.2 cm(2) y(-1) and 0.9 to 4.1 y(-1), respectively for the biodiffusive-like and non-local transports. Calculated biodiffusive-like coefficient was between 1.0 and 2.3 cm(2) y(-1) for the deep tracers. For both tracers, the E. cordatum population presented the highest reworking coefficients. Among the morphological and/or ethological parameters that could determine overall patterns of reworking and differences between species, results have shown a direct relationship between the apparent biodiffusive mixing and the biovolume of the individuals (D-b=0.35 * Biovolume). This suggests that the biovolume-of macrofauna may allow a rough estimate of the biodiffusive-like reworking intensity of particles deposited on the sediment surface. (c) 2007 Elsevier B.V. All rights reserved.
|
|
