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At least 19 recordsLinked to original sources
PubMed1967

Manned submersibles for research. These immature but developing tools open another door for examining history and current processes.

The past decade has seen the development of small submersibles as a new and effective tool of geology, acoustics, marine biology, and physical oceanography. As with all tools, it has special capabilities and limitations. The methods of use and the needed engineering improvements are being identified. Scientists, engineers, government, and industry are responding so that advances toward both less-expensive simple vehicles and high-performance complex vehicles are proceeding.

Ecological Systems, Closed↗
PubMed1989

Bioluminescence in oceanology.

For analytical purposes bioluminescence can be used in three main ways: 1. luminescence measurement of bioluminescent system components isolated in vitro; 2. determination of luminous organisms' reaction to the in vivo test-action; 3. measurement of bioluminescence in marine ecological systems. The majority of the reports of this Symposium are dealing with the first two topics. The aim of our presentation is to draw attention to the third one. The possibilities of bioluminescent analysis are wider than its traditional scheme of applications in the laboratory, when the emitting system is withdrawn from a native source and is placed in a cuvette of the light measuring device. The reverse scheme is also possible, i.e. the device can be introduced into light emitting system such as a marine biocenosis--the community of the sea inhabitants--where we obtain a highly sensitive and rapid means of gaining the information on the vital activity of marine ecosystems, i.e. their spatial structure, rhythms, man's influence upon them, etc. The present communication will consider the possibilities of this form of bioluminescent analysis.

Circadian Rhythm↗
PubMed1992

Molecular phylogeny of some polychaete annelids: an initial approach to the Atlantic-Mediterranean speciation problem.

The polychaete Eupolymnia nebulosa (family Terebellidae) displays two alternative modes of reproduction. In the Mediterranean, larvae are brooded in a mucous mass while in the Atlantic and English Channel, larvae follow a plank-tonic development. This paper attempts to discern whether this difference is expressed at the population, infraspecies, or species level. Specimens of E. nebulosa and representatives of a number of control species were sampled from Atlantic/English Channel and Mediterranean locations. Genetic sequencing of the Large-subunit ribosomal RNA 5' end of six representative species allowed one to infer the relative position of E. nebulosa within the Terebellidae and the position of the latter within the animal kingdom. The relative genetic distances calculated between the different species were also used to approach the speciation problem raised by the differences between the Mediterranean and Atlantic/English Channel population of E. nebulosa. The genetic distance between Mediterranean and Atlantic populations of both E. nebulosa and Lanice conchilega are of the same order, suggesting that differences between the populations of E. nebulosa are infraspecific.

Animals↗
PubMed1987

Prey localization by surface wave ray-tracing: fish track bugs like oceanographers track storms.

Surface-feeding fish accurately determine direction and distance to the center of a concentric wave stimulus, even if only a single, short lasting wave train is presented. It has been suggested that one cue used by these fish to localize the wave center is the distance dependent frequency modulation of the initial part of a wave stimulus. Here we show how the distance information contained in the fractional frequency change of a capillary wave group can be decoded. We suggest that wave source localization in surface-feeding fish in part is based on a principal similar to that used by oceanographers to track storms by the frequency change of forerunners of swell.

Animals↗
PubMed1975

Medical hazards of the coral reef.

An account is given of some aspects of poisonings sustained by coming into contact with animals of the coral reefs of the Fiji Islands. Poisonings can be grouped into those in which the toxin is introduced parenterally-envenomings, and those in which it is ingested. Illustrative case histories are presented of injuries from 2 echinoderms and of envenoming from the "deadly" stonefish. A therapeutic approach to puffer-fish poisoning is mentioned and the problem of ciguatera poisoning is outlined.

Adult↗
PubMed1990

Deep water parasites.

Few geographically local comprehensive studies on deep-sea parasites have been done. A recent study of parasitism in midwater fishes conflicts with broad generalizations previously advanced. Surveys of demersal fishes and macrofaunal invertebrates in the North Atlantic indicate 1) there is little evidence of coherence and continuity of faunal zones around the ocean basin and 2) that the community concept should be abandoned because faunal assemblages only persist on a local scale. Parasitological evidence supports this view. The implications are that the parasite species distributions and character of parasite faunas will vary according to the distribution of the fishes and local faunal assemblages.

Animals↗
PubMed2026

Minimizing decompression and warming during deep seawater collection increases abundance and activity of autochthonous bacteria and archaea.

The deep ocean hosts autochthonous pressure-adapted microorganisms that are unique to this environment, as well as allochthonous pressure-sensitive members transported from shallow depths by vertical advection and particle-sinking. However, conventional sampling instruments decompress and warm deep-sea samples during retrieval, potentially altering microbial properties when studied ex situ. Here, we assess this potential sampling bias by comparing seawater microbial communities collected with or without measures aimed at minimizing pressure and temperature effects. When compared to samples collected under pressurized conditions, conventional sampling (using Niskin bottles) was found to affect prokaryotic cells retrieved by reducing their total numbers, diminishing protein synthesis activity (>10%), and also causing overall shifts in the community composition. The most significant compositional change was a >20% decrease in metagenomic archaeal representation (TACK-group/Thaumarchaeota/Nitrososphaerota). Deep-sea bacterial groups had mixed responses to preserving pressure during retrieval, with some groups exhibiting higher representation when samples were maintained pressurized (e.g. members of the family Pelagibacteraceae, unclassified Thiotricales, Thioglobaceae, and Chitinophagaceae), whereas others increased their representation when decompressed (e.g. Burkholderiaceae, Comamonadaceae, and Oxalobacteraceae). This study reveals the existence of bias introduced by the complete decompression of samples retrieved with traditional instrumentation, as well as a decrease in overall bacterial activity when samples are completely decompressed during retrieval. Additionally, incubations lasting for >24 h were shown to transform the original prokaryotic community composition. Precautions addressing these effects are necessary to enhance the reliability of ex situ measurements and improve our understanding of deep-sea microbial ecology and biogeochemistry.

Seawater↗