Naslov
Seagrass bed expansion associated with sediment deposition in the Novigrad Sea, Croatia

Autori
Mokos, Melita ; Schultz, Stewart T. ; Kruschel, Claudia

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts of the 46th European Marine Biology Symposium (46th EMBS, Rovinj) / Travizi, Ana ; Iveša, Ljiljana ; Fafanđel, Maja - Rovinj : Institut Ruđer Bošković, Centar za istraživanje mora Rovinj, 2011, 43-43

Skup
46th European Marine Biology Symposium (46th EMBS, Rovinj)

Mjesto i datum
Rovinj, Hrvatska, 12.09.2011. - 16.09.2011

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
seagrass ; sediment deposition ; Adriatic sea

Sažetak
Sediment movement is a major force in the evolutionary ecology of seagrasses. Sediment movement can cause retreat or expansion of the seagrass bed, and sorting of species according to their tolerances of erosion or deposition. The objectives of this study were 1) to assess the effectiveness of DGPS/videography in demonstrating sediment movement and seagrass bed expansion, 2) to apply the method to Novigrad Sea to quantify changes in species composition or bed expanse/retreat in response to sediment movement. During 2007, 2008 and 2009, 23 transects in the Novigrad Sea were monitored using a boat-based DGPS videography. Three seagrass species occur in this area: Zostera noltii, Zostera marina and Cymodocea nodosa. These seagrasses form a continuous mixed meadow from the surface to a depth of 6, 6 m growing on sandy or muddy substrate. Video analysis with sonagraphy gave us information on ground type (rock, sand), ground cover (algae, seagrass), seagrass density, and depth. Seagrass gain occurred in 2007/2008, the year of net sediment accumulation, while seagrass loss occurred in 2008/2009, the year of net sediment erosion. Seagrass gain at the deep end of the transect was significantly positively associated with net sediment accumulation and this relationship is non-linear, with moderate levels of sedimentation stimulating seagrass expansion, and high levels inhibiting expansion. Cymodocea nodosa, which is the most tolerant species in this mixed bed to sediment burial and erosion, inhabits area with highest sediment movement, which confirms our hypothesis that more tolerant species occupy regions of highest sediment movement. Seagrass expansion occurred in areas where sedimentation raised the ground level above the minimum light threshold for seagrass colonization. We conclude that the method of DGPS-tracked, boat- based underwater videography was able to demonstrate statistically significant associations between annual sediment movement and change in total and species-specific seagrass cover over a 135-ha region of subtidal habitat with a moderate investment of time and labor.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA