- Email: [email protected]
A low-frequency spectrum and cross-spectrum analyzer
54
Oceanographic Abstracts
MADSEN, F. J., 1961. On the zoogeography and origin of the abyssal fauna. Galathea Rep. 4: 177-218. A review and discussion of some of the general problems of the abyssal fauna is given on the basis of knowledge of the Porcellanasteridae. These sea=stars with no fossil records, can be assumed to have evolved in the Late Mesozoic from astropeetinid-like ancestors, which in bathyal depths (Murray's mud-line), changed from a predatory or scavenging to a primarily mud-swallowing way of feeding, and thereafter spread outwards and downwards, evidently constituting one of the oldest elements in the present abyssal fauna. The endemic deep-sea families and orders have, in general, a geological history traceable to the Late Mesozoic only, and it is possible that they did not migrate from bathyal to abyssal depths until the late Tertiary. During this period, from Oligocene to Pliocene, the gradual lowering of the abyssal temperatures also may have caused extinction of possible older abyssal faunal elements. The non-endemic abyssal fauna will include late Tertiary invaders too, from the shallower depths of the colder regions, and it is well known that many abyssally-occurring species are polar, represent a late Quaternary invasion, still in progress. The concept of a cosmopolitan abyssal level-bottom faunal element is supported by knowledge of the Porcellanasteridae, of which six of the fourteen species known from more than two localities occur in all three o:eans. When coelenterates, echinoderms, and also polychaetes, sipunculids and various arthropods (pycnogonids and cirripeds), are considered, then the truly abyssal species appear to be very widely distributed. The zoogeographical boundary in the deep-sea (next in importance to that formed by the American continents), is, judging by the distribution of the porcellanasterids, constituted by the ecologically unfavourable Mid-Pacific deep-sea. MALLET, L., L. V. PERDRIAU and J. PERDRIAU, 1963. Pollution par les hydrocarbures polybenz6niques du type henzo-3. 4 pyr6ne de la region occidentale de l'Oc6an Glacial Arctique. C. R., Acad. Sci., Paris, 256 (16): 3487-3489. A la suite d'une exploration de la r6gion des p6ches de l'O=6an Glacial Arctique, les auteurs ont relev6 dans les s6diments et surtout dans le milieu biologique la pr6sence d'hydrocarbures polybenz6niques du type benzo-3.4 pyr~ne. L'existence de cette substance fait pr6sumer une pollution g6n6rale de l'hemisph~re nord. MAR6ALEF, R., 1962. Organisation spatiale et temporelle des populations de phytoplancton dans un secteur du littoral m6diterran6en espagnol. Pubbl. Sta. Zool., Napoli, 32 (Suppl.): 336-348. The annual cycle of phytoplankton off Castellon (40 ° lat. N.) over depths up to 100 m, is characterized generally by three pulses. Phosphate concentration is always a limiting factor. Cooling of the surface layers in the fall mixes water in increasing thickness and mobilizes the small local reserve of nutrients. The turbulence represents a premium for species without active movement and with a relatively high chlorophyll content. The initial populations in this succession contain an important proportion of Thalassiothrix, Thalassionema, Asterionella. A true upwelling occurs in February or March. The upwelled waters are rapidly invaded by Chaetoceros and small flagellates. The intensity of this upwelling determines the total production for the whole year. Towards the end of March or later, the surface current that, most of the year, flows from NE to SW, changes its direction and the coastal region is invaded by off-shore water of S and SE origin that wash away local populations. At the bzginning it is very transparent and poor, but later, a certain amount of phosphate induces a spring bloom with Nitzschieila, Bacteriastrum, Rhizosolenia and small flagellates. A thermocline is formed and, only diatoms associated with Protozoa remain afloat, together with the bulk of the dinoflagellates and other flagellates, which last until the fall. Sometimes, very local blooms of Chaetoceros compressus and Nitzschiella are observed in summer. Heterogeneity in the spatial distribution of phytoplankton populations is often very important and can be described as the consequence of local differences in the speed of succession of populations, reflected also in the composition of pigments and other synthetic characteristics of populations. The littoral plankton has a rather low production; nevertheless it manages to export part of this production to neighbouring ecosystems (bottom, offshore, pelagic) and remains always in a state of lower maturity than the last named ecosystems. MAPaNO, L. B., 1962. La determinazione del fosforo nei sedimente Adriatici. Arch. Ocean. LimnoL, XII (3): 267-274. Ist. Sper. Talass., Trieste, Pubbl. No. 397. The Burton and Riley method for the determination of total phosphorus was used in the analysis of five cores taken in the central Adriatic between Pescara and Sebenico. All the samples contain the same amount of phosphorus with the exception of a richer one taken near the coast. The phosphorus concentration is not dependent on the depth. MARKS, W. and P. SrRAOSSER, 1963. A low-frequency spectrum and cross-spectrum analyzer. In: Ocean Wave Spectra, Proc. Conf., Easton, Md., May 1-4, 1961, Prentice-Hall, N.J., 273-280. The David Taylor Model Basin spectrum analyser is described. The extension to cross-spectrum analysis by use of matched filters is discussed. Some preliminary experiments to check the method provide a general verification but show the need for further experimentation on the matched filters and phase-shifting components of the system.
Oceanographic Abstracts
MADSEN, F. J., 1961. On the zoogeography and origin of the abyssal fauna. Galathea Rep. 4: 177-218. A review and discussion of some of the general problems of the abyssal fauna is given on the basis of knowledge of the Porcellanasteridae. These sea=stars with no fossil records, can be assumed to have evolved in the Late Mesozoic from astropeetinid-like ancestors, which in bathyal depths (Murray's mud-line), changed from a predatory or scavenging to a primarily mud-swallowing way of feeding, and thereafter spread outwards and downwards, evidently constituting one of the oldest elements in the present abyssal fauna. The endemic deep-sea families and orders have, in general, a geological history traceable to the Late Mesozoic only, and it is possible that they did not migrate from bathyal to abyssal depths until the late Tertiary. During this period, from Oligocene to Pliocene, the gradual lowering of the abyssal temperatures also may have caused extinction of possible older abyssal faunal elements. The non-endemic abyssal fauna will include late Tertiary invaders too, from the shallower depths of the colder regions, and it is well known that many abyssally-occurring species are polar, represent a late Quaternary invasion, still in progress. The concept of a cosmopolitan abyssal level-bottom faunal element is supported by knowledge of the Porcellanasteridae, of which six of the fourteen species known from more than two localities occur in all three o:eans. When coelenterates, echinoderms, and also polychaetes, sipunculids and various arthropods (pycnogonids and cirripeds), are considered, then the truly abyssal species appear to be very widely distributed. The zoogeographical boundary in the deep-sea (next in importance to that formed by the American continents), is, judging by the distribution of the porcellanasterids, constituted by the ecologically unfavourable Mid-Pacific deep-sea. MALLET, L., L. V. PERDRIAU and J. PERDRIAU, 1963. Pollution par les hydrocarbures polybenz6niques du type henzo-3. 4 pyr6ne de la region occidentale de l'Oc6an Glacial Arctique. C. R., Acad. Sci., Paris, 256 (16): 3487-3489. A la suite d'une exploration de la r6gion des p6ches de l'O=6an Glacial Arctique, les auteurs ont relev6 dans les s6diments et surtout dans le milieu biologique la pr6sence d'hydrocarbures polybenz6niques du type benzo-3.4 pyr~ne. L'existence de cette substance fait pr6sumer une pollution g6n6rale de l'hemisph~re nord. MAR6ALEF, R., 1962. Organisation spatiale et temporelle des populations de phytoplancton dans un secteur du littoral m6diterran6en espagnol. Pubbl. Sta. Zool., Napoli, 32 (Suppl.): 336-348. The annual cycle of phytoplankton off Castellon (40 ° lat. N.) over depths up to 100 m, is characterized generally by three pulses. Phosphate concentration is always a limiting factor. Cooling of the surface layers in the fall mixes water in increasing thickness and mobilizes the small local reserve of nutrients. The turbulence represents a premium for species without active movement and with a relatively high chlorophyll content. The initial populations in this succession contain an important proportion of Thalassiothrix, Thalassionema, Asterionella. A true upwelling occurs in February or March. The upwelled waters are rapidly invaded by Chaetoceros and small flagellates. The intensity of this upwelling determines the total production for the whole year. Towards the end of March or later, the surface current that, most of the year, flows from NE to SW, changes its direction and the coastal region is invaded by off-shore water of S and SE origin that wash away local populations. At the bzginning it is very transparent and poor, but later, a certain amount of phosphate induces a spring bloom with Nitzschieila, Bacteriastrum, Rhizosolenia and small flagellates. A thermocline is formed and, only diatoms associated with Protozoa remain afloat, together with the bulk of the dinoflagellates and other flagellates, which last until the fall. Sometimes, very local blooms of Chaetoceros compressus and Nitzschiella are observed in summer. Heterogeneity in the spatial distribution of phytoplankton populations is often very important and can be described as the consequence of local differences in the speed of succession of populations, reflected also in the composition of pigments and other synthetic characteristics of populations. The littoral plankton has a rather low production; nevertheless it manages to export part of this production to neighbouring ecosystems (bottom, offshore, pelagic) and remains always in a state of lower maturity than the last named ecosystems. MAPaNO, L. B., 1962. La determinazione del fosforo nei sedimente Adriatici. Arch. Ocean. LimnoL, XII (3): 267-274. Ist. Sper. Talass., Trieste, Pubbl. No. 397. The Burton and Riley method for the determination of total phosphorus was used in the analysis of five cores taken in the central Adriatic between Pescara and Sebenico. All the samples contain the same amount of phosphorus with the exception of a richer one taken near the coast. The phosphorus concentration is not dependent on the depth. MARKS, W. and P. SrRAOSSER, 1963. A low-frequency spectrum and cross-spectrum analyzer. In: Ocean Wave Spectra, Proc. Conf., Easton, Md., May 1-4, 1961, Prentice-Hall, N.J., 273-280. The David Taylor Model Basin spectrum analyser is described. The extension to cross-spectrum analysis by use of matched filters is discussed. Some preliminary experiments to check the method provide a general verification but show the need for further experimentation on the matched filters and phase-shifting components of the system.