Biological oceanography最新文献

{"title":"Phytodetritus on the deep-sea floor in a central oceanic region of the Northeast Atlantic","authors":"H. Thiel, O. Pfannkuche, G. Schriever, K. Lochte, A. Gooday, C. Hemleben, R. Mantoura, C. Turley, J. Patching, F. Riemann","doi":"10.1080/01965581.1988.10749527","DOIUrl":"https://doi.org/10.1080/01965581.1988.10749527","url":null,"abstract":"In a midoceanic region of the northeast Atlantic, patches of freshly deposited phytodetritus were discovered on the sea floor at a 4500 m depth in July/August 1986. The color of phytodetritus was variable and was obviously related to the degree of degradation. Microscopic analyses showed the presence of planktonic organisms from the euphotic zone, e.g., cyanobacteria, small chlorophytes, diatoms, coccolithophorids, silicoflagellates, dinoflagellates, tintinnids, radiolarians, and foraminifers. Additionally, crustacean exuviae and a great number of small fecal pellets, “minipellets,” were found. Although bacteria were abundant in phytodetritus, their number was not as high as in the sediment. Phytodetrital aggregates also contained a considerable number of benthic organisms such as nematodes and special assemblages of benthic foraminifers. Pigment analyses and the high content of particulate organic carbon indicated that the phytodetritus was relatively undegraded. Concentrations of proteins, carbohydrates, chloroplastic pigments, total adenylates, and bacteria were found to be significantly higher in sediment surface samples when phytodetritus was present than in equivalent samples collected at the same stations in early spring prior to phytodetritus deposition. Only the electron transport system activity showed no significant difference between the two sets of samples, which may be caused by physiological stress during sampling (decompression, warming). The chemical data of phytodetritus samples displayed a great variability indicative of the heterogeneous nature of the detrital material. The gut contents of various megafauna (holothurians, asteroids, sipunculids, and actiniarians) included phytodetritus showing that the detrital material is utilized as a food source by a wide range of benthic organisms. Our data suggest that the detrital material is partly rapidly consumed and remineralized at the sediment surface and partly incorporated into the sediment. Incubations of phytodetritus under simulated in situ conditions and determination of the biological oxygen demand under surface water conditions showed that part of its organic matter can be biologically utilized. Based on the measured standing stock of phytodetritus, it is estimated that 0.3–3% of spring primary production sedimented to the deep-sea floor. Modes of aggregate formation in the surface waters, their sedimentation, and distribution on the seabed are discussed.","PeriodicalId":262997,"journal":{"name":"Biological oceanography","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128951039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Family of Deep-Sea Planktonic Copepods, the Paralubbockiidae (Copepoda: Poecilostomatoida)","authors":"G. Boxshall, R. Huys","doi":"10.1080/01965581.1988.10749525","DOIUrl":"https://doi.org/10.1080/01965581.1988.10749525","url":null,"abstract":"AbstractThe deep-sea planktonic copepod Paralubbockia longipedia is redescribed from the type specimens, and a new family of Poecilostomatoida is proposed to accommodate it. The Paralubbockiidae fam. nov. is characterized by two unique plesiomorphies, the ventrally located fifth legs and the retention of a separate maxillulary palp, and by the apomorphic states of the endopods of the swimming legs and of the antenna. The sister group of the Paralubbockiidae is identified as the family Oncaeidae. These are the only two poecilostomatoid families that have retained a vestige of the geniculation mechanism in the antennules of the male. The genus Laitmatobius Humes is here regarded as incertae sedis within the lineage comprising the Oncaeidae and the Paralubbockiidae.","PeriodicalId":262997,"journal":{"name":"Biological oceanography","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122861804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}