Interactions between the behaviour of an Euphasia superba superswarm, observed in November 1994 in the Ross Sea, and its physical and pelagic environment (Abstract/Poster in atti di convegno)

Type
Label
  • Interactions between the behaviour of an Euphasia superba superswarm, observed in November 1994 in the Ross Sea, and its physical and pelagic environment (Abstract/Poster in atti di convegno) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Azzali M. (1), Leonori I. (1), De Felice A. (1), De Pasqualis S. (1), Biagiotti I. (1), Russo A (2). (2007)
    Interactions between the behaviour of an Euphasia superba superswarm, observed in November 1994 in the Ross Sea, and its physical and pelagic environment
    in Ecologia, limnologia e oceanografia: quale futuro per l'ambiente? Congresso congiunto XVIII AIOL e XVII SitE, Ancona
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Azzali M. (1), Leonori I. (1), De Felice A. (1), De Pasqualis S. (1), Biagiotti I. (1), Russo A (2). (literal)
Pagina inizio
  • 201 (literal)
Pagina fine
  • 206 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni
  • http://www.congresso.ecologia.it/atti/abstracts_XVII.pdf (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#descrizioneSinteticaDelProdotto
  • A characteristic of Antarctic krill is that they live in dense swarms of millions of individuals and such swarms have significant effect on the physical and pelagic environment because their density is about 3% higher than the surrounding water, their phytoplankton carbon and oxygen demand is very high and in order to meet these requisite a krill swarm needs to move actively and quickly through the water. An enormous Euphausia superba swarm (“superswarm”) was observed on the 22nd and 23 rd November 1994 at Latitude 74.65° and Longitude 175° in the Ross Sea. The mean biomass density of this swarm was estimated between 800 and 1100 g/m2 (i.e around 1600-2200 animal/m2). The swarm was distributed over an area of around 250 km2 and between 10 and 120 m depth. The formation and splitting of the swarm, together with its internal organization was observed acoustically and its surrounding environment sampled with CTD. The paper reports in detail (every 2 m in depth and every 150 m in length) the spatial density distribution of the superswarm, makes assumption on its biologically-induced effect on the environment, describes its progressive dispersion and dissolution and the parallel changing of the gross features of the physical environment and of krill predators. In particular it results that the density difference between the krill swarm and the surrounding sea water may be sufficient to produce a water circulation within the swarm of at least 3 cm/sec. (literal)
Note
  • Poster (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (1) Istituto di Scienze Marine, CNR, Largo Fiera della Pesca, 60125 Ancona, Italia (2) Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italia (literal)
Titolo
  • Interactions between the behaviour of an Euphasia superba superswarm, observed in November 1994 in the Ross Sea, and its physical and pelagic environment (literal)
Abstract
  • A characteristic of Antarctic krill (Euphausia superba) is that they live in dense swarms of millions of individuals and such swarms have significant effect on the physical and pelagic environment. Krill body density is about 3% higher than the surrounding water and krill phytoplankton carbon demand is very high, therefore krill swarms need to move continuously and quickly through the water and their movements influence the gross features of the bio-physical environment together with the spatial distribution of krill-eating predators. An enormous aggregation of E. superba swarms was found on the 22nd and 23rd Nov. 1994 in an area of about 2100 km2, in the central part of the Ross Sea. The mean krill areal density resulted 860 g/m2 distributed from 10 to 120m in depth. The bulk of this aggregation was centered on a gigantic swarm containing roughly 57000 million adult Antarctic krill. Krill density in the same area, sampled on the 28-29th Nov., resulted 30 times lower than five days before and the \"super swarm\" apparently had scattered Northwestward in small and dense swarms. The paper concentrates on both the gigantic swarm found on the 23rd November and one of the swarms sampled acoustically on the 29th November, on the respective surrounding bio-physical environments and on the predators feeding in the swarm areas. The bio-physical factors that may limit swarm density and duration and the influence of swarms on the surrounding environment and predator spatial distribution are discussed. (literal)
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