Naslov
Characteristics of the sediment under the canopy of invasive alga Caulerpa racemosa var. cylindracea
(Characteristics of the sediment under the canopy of invasive algaA Caulerpa racemosa var. cylindracea)

Autori
Matijević, Slavica ; Žuljević, Ante ; Bogner, Danijela ; Despalatović, Marija ; Antolić, Boris ; Nikolić, Vedran

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

Izvornik
Abstracts of the Mediterranean Seagrass Workshop '09 / Di Carlo, G. ; Calladine, A. ; Žuljević, A. - : MSW09 Committees, 2009, 60-61

Skup
Mediterranean Seagrass Workshop '09

Mjesto i datum
Hvar, Hrvatska, 06.09.2009. - 10.09.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Caulerpa racemosa var. cylindracea; physico-chemical characteristics; sediments; Adriatic Sea; Croatia

Sažetak
This paper presents preliminary investigations of physico-chemical characteristics of sediments under the canopy of invasive C. racemosa var. cylindracea in the periods of alga's maximum development in relation to sediments unaffected with the alga. Samplings and measurements were taken in October 2002 at Priježba Cove (Pelješac Peninsula, Adriatic Sea) at the sites where the alga has developed the densest canopy and completely covered the sea floor: (I) the sandy bottom surrounded by seagrass P. oceanica meadow and (II) the dead mats of P. oceanica, each compared with control site not affected by the invasive alga and distanced 10–20 m. Parameters investigated in sediment samples were: granulometric composition, content of organic matter, carbonates, organic carbon, total nitrogen and phosphorus concentration as well as redox potential state. Oxygen concentration was determined in the seawater samples taken from the canopy of C. racemosa var. cylindracea, while at control sites bottom seawater samples 0-5 cm under the sediment were collected. Biometric analyses of C. racemosa var. cylindracea canopy were obtained. The dominant particle size in all sediment samples was sand (0.063-2 mm). Organic matter content in surface sediment layer (0-2 cm) at sites invaded by C. racemosa var. cylindracea was elevated in relation to control sites (9.6 to 1.7%, respectively). Organic carbon and total nitrogen ratios at invaded sites were >10, indicated to the origin of the organic matter from the marine sea grasses which were captured by the canopies. Sediment redox potential at invaded sites was negative (from -272 to -50 mV) and decreased with depth, while at control sites it was almost constantly positive. Oxygen saturations in the seawater from the C. racemosa var. cylindracea canopy were from 0 - 36% in relation to 90 - 96% at the control sites. These results indicate to hypoxic and anoxic pathways of degradation of organic material accumulated below the canopy of C. racemosa var. cylindracea.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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