engleski

In situ manipulation of vertically migrating gelatinous zooplankton using nighttime blue-water scuba in the South-central Adriatic Sea

Technological advance in undersea exploration (e.g. tethered cameras, remotely operated vehicles [ROVs], Autonomous Underwater Vehicles [AUVsG, and manned submersibles)have opened new windows into diversityand distribution of fragile gelatinous organisms in the vast mesopelagic realm(300 m-1000 m deep). While exstraordinary in expanding our view of its richness, mesopelagic exploration remains largely a "look but don't touch" environment and this limits of our ability to understand these animals through physical manipulation relevant to the finer scales of the individual organism. We have been conducting a series of in situ observations and manipulations using blue-water SCUBA during the night at a 1, 200 m station centraly located in the southern Adriatic Sea. We report here on a suite of vertically migrating gelatinous animals, including the narcomedusa Solmissus albescens and the physonect siphonophores Forskalia formosa and Agalma elegans, whose ranges extend to the mesopelagic realm during the day, but reach SCUBA diving depths during the night. Our in situ approach combined with proximity to shore exploits the natural vertical migratory behavior of some mesopelagic species, and we therefore add to the widening spectrum of methods needed to evaluate these ecologically important yet difficult to study organisms.

vertical migration; in situ; behavior; hydrodynamics; Adriatic Sea; night-time SCUBA

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