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WHOI biological oceanographers study the biology of individual marine organisms, their spatial and temporal distributions, and how they interact both with their surrounding environment and with each other.
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Technical ReportA portable listening and recording system for underwater sound(Woods Hole Oceanographic Institution, 1962-11) Watkins, William A.This report describes the Rowboat System, a compact, self contained portable listening and recording system designed and built at the Woods Hole Oceanographic Institution for listening to and recording underwater sounds in the frequency range of 30 to 30,000 cps. it is designed for animal sounds primarily. The system is all-transistor and includes a hydrophone-matching preamplifier, a 65-db amplifier, a record amplifier and bias oscillator, a meter and speech amplifier, and a 1000-cps speed reference oscillator. These are built around a commercial spring-wound tape deck and are battery powered. All are comfortable in a one-half cubic foot box.
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Technical ReportA key to the stromateoid fishes(Woods Hole Oceanographic Institution, 1969-09) Haedrich, Richard L. ; Horn, Michael H.Our primary purpose in preparing "A Key to the Stromateoid Fishes" is to provide field workers and curators with a convenient and concise aid for the identification of the diverse species in this somewhat difficult group . Secondarily, we hope to present , through the keys , a summary of the present state of our knowledge of these fi.shes, and to indicate areas where further investigation is needed .
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Technical ReportHydrocarbon incorporation into the salt marsh ecosystem from the West Falmouth oil spill(Woods Hole Oceanographic Institution, 1971-11) Burns, Kathryn A. ; Teal, John M.The oil barge "Florida" ran aground just off Little Island, West Falmouth, Massachusetts on September 16, 1969. About 175,000 gallons of Number Two fuel oil leaked into Buzzards Bay and the adjacent Wild Harbor Marsh. This report presents the results of analyses done on marsh muds and organisms collected nearly a year after the spill. We studied the incorporation of polluting hydrocarbons into, and their movement through the marsh ecosystem. Analyses of surface muds agreed well with observations on plant growth. The dead areas were the most heavily polluted. A deep mud core in the dead area showed oil has penetrated to at least 70 cm. Virtually all the marsh organisms living in the contaminated area were affected by the oil at least to the extent that they accumulated oil hydrocarbons in their tissues. Our data suggest that two processes may occur as the oil passes through the marsh ecosystem. There may be a progressive loss in the straight chain hydrocarbons in relation to branched chain, cyclic and aromatic hydrocarbons. There also appears to be a selection for the higher boiling fractions of the contaminants higher up the food chain.
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Technical ReportA key to the stromateoid fishes(Woods Hole Oceanographic Institution, 1972-03) Haedrich, Richard L. ; Horn, Michael H.Our primary purpose in preparing "A Key to the Stromateoid Fishes" is to provide field workers and curators with a convenient and concise aid for the identification of the diverse species in this somewhat difficult group. Secondarily, we hope to present, through the keys, a summary of the present state of our knowledge of these fishes, and to indicate areas where further investigation is needed. The keys which compose this handbook have been derived from several sources. Some are slightly modified from already published or about-to-be-published sources. Others form a part of manuscripts in preparation. A third group of keys has been constructed from published species descriptions and our own often meagre data. The keys are intended primarily for larger specimens. Small stromateoids are particularly confusing, and it is not our purpose to treat them here. The well-known and marked allometric growth in stromateoids remains a problem, and those who use these keys should be aware that the body proportions of very large and/or very small specimens can fall well outside the limits here set. We expect and hope for corrections and improvements to the keys, and have left them double-spaced so comments may be written in by users. We have not attempted to settle nomenclatural problems, but have used the oldest name we know of when a choice is necessary. Neither have we gone into the problem of synonymy to any great extent. In some cases we have approached this problem by including two names under one couplet in a key. The choice of which name to employ is thus passed on to the user.
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Technical ReportElectromagnetic flow sensors(Woods Hole Oceanographic Institution, 1974-03) Lawson, Kenneth ; Kanwisher, John W.Flow sensors based on the principle of electromagnetic induction were investigated as alternatives to commonly used mechanical devices utilizing rotors and propellers. Prototype sensors were constructed showing considerable promise. Measurement accuracy in excess of .01 knot seems feasible with devices suited to long term battery operation. The inertial effects and many of the reliability problems inherent in moving part devices would be overcome by use of an electromagnetic sensor.
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ThesisTransient structure in benthic communities : the effects of oxygen stress, burial and high rates of sedimentation(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-04) Nichols-Driscoll, JeanThe influence of natural short-term fluctuations in environmental parameters on three components of transient benthic invertebrate community structure: abundance of individuals and species, biomass of individuals, and species diversity, were investigated in this study. The effect of low dissolved-oxygen on transient benthic community structure was studied with samples from Golfo Dulce, an intermittently anoxic basin off the west coast of Costa Rica and the Posa de Cariaco, an anoxoic trench off the north coast of Venezuela. Periodic fluctuations in oxygen concentration were accompanied by a community numerically dominated by a single polychaete species and low species diversity. As the frequency of fluctuations in oxygen concentration decreased, the number of species and individuals in the community increased with a corresponding increase in species diversity. In contrast to fluctuating oxygen conditions which eliminated many species from the community, fluctuating amounts of suspended matter in the bottom water allowed one species to proliferate while maintaining the total species list length. High rates of terrigenious sedimentation occurring naturally off the Spanish Sahara coast produced conditions which apparently hampered the feeding mechanisms of a spionid polychaete. Further offshore, where the diversity should be expected to increase, the spionids were able to flourish. The result was greater numerical abundance and biomass offshore and a lower transient diversity value. Results of simulation of catastophic burial by in situ burial of small isolated portions of Buzzards Bay sediment indicated that sedimentation rates recorded off Spanish Sahara would not eliminate species by burial. However, the small size of the organisms found off Spanish Sahara is probably a result of the constant expenditure of energy for escape. In regions of fluctuating environmental conditions, diversity values are low, principally because of dominance by a single species. Increasingly stable conditions, even though stressful, result in a more even distribution of individuals among the species present and a correspondingly high transient value.
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ThesisThe relationship between cupric ion activity and the toxicity of copper to phytoplankton(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-04) Sunda, WilliamThe purpose of this investigation is to quantify the relationship between cupric ion activity and the toxicity of copper to phytoplankton and further to study the effect on copper toxicity of naturally occurring organic ligands. Culture experiments with an estuarine diatom Thalassiosira pseudonana (clone 3H) in highly chelated seawater media demonstrated that copper induced growth rate inhibition and 3 to 4 day cellular uptake of copper are both related to the calculated free cupric ion activity and are independent of the total copper concentration. Cupric ion activity and total copper concentration were independently altered through various combinations of chelator (trishydroxymethyl amino methane) concentration, total copper concentration, and pH. Cellular copper content, in moles per cell, followed a hyperbolic relationship Cu/cell = 4.8 x 1-016 aCu/aCU + 10-9.2 where aCu is the free cupric ion activity. The above relationship suggests a reversible binding of copper to a single set of cellular ligand sites having a total binding capacity of 4.8 x 10-16 moles per cell and an association constant for reaction with copper of 109.2. For T. pseudonana (clone 3H) copper was inhibitory at pCu values below 10.7 (i.e. cupric ion activities above 10-10.7) with total growth inhibition occurring at pCu values below 8.3. The relationship between growth rate inhibition and cupric ion activity was not a simple hyperbolic relationship as was observed in the case of copper uptake. For an estuarine green alga Nannochloris atomus (clone GSB Nanno) and an open ocean strain of T. pseudonana (clone 13-1) partial growth rate inhibition occurred in the pCu ranges 10.3 to 8.4 and approximately 10 to 8, respectively. Comparison of these growth inhibitory pCu levels with a calculated estimate of the pCu of seawater of pH 8.2 containing a typica1 total copper concentration of 0.012 μM and having no significant copper chelation, indicates that natural cupric ion activity levels in seawater may be inhibitory to these three clones. Evidence was found for the complexation of copper by extracellular products of the alga T. pseudonana (clone 3H). Cupric ion selective electrode measurements of copper complexation in unused low salinity culture media and in identical media in which algae had been grown and from which they were subsequently filtered showed a higher degree of copper complexation in the used media. Parallel studies of copper toxicity and cellular copper uptake in an unused medium and in a culture filtrate demonstrated a lower copper toxicity and a decreased cellular copper uptake in the used medium. Cupric ion-selective electrode measurements and bioassay experiments support the hypothesis that copper is complexed by organic ligands in at least some natural waters. Copper added to filtered untreated river water is more highly complexed than that added to river water that has been uv irradiated to remove some portion of the dissolved organic matter. Copper toxicity to N. atomus is significantly increased in seawater from Vineyard Sound and in salt marsh water subjected to prior ultraviolet irradiation.
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ThesisDistribution of hydrocarbons in a salt marsh ecosystem after an oil spill and physiological changes in marsh animals from the polluted environment(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-06) Burns, Kathryn A.The studies described in this thesis were designed to answer several problems relating to the recovery of a salt marsh heavily polluted by an accidental spill of Number 2 fuel oil. Field and laboratory studies were conducted for 5 years comparing the oiled Wild Harbor Marsh with the unoiled Sippewissett Marsh, both on Buzzards Bay in Massachusetts. The data contributes information 1) on the incorporation of oil into the sediments and organisms at the oiled marsh, 2) on the residence times of certain components of the oil in the marsh ecosystem, 3) on changes in chemical composition of the oil with time due to physical and chemical weathering processes and biochemical degradation of hydrocarbons, 4) on the effects of oiled sediments on the population distribution, behavior, and survival of the intertidal fiddler crab, Uca pugnax, 5) on the relatively small ability of Uca to metabolize hydrocarbons, 6) on the presence of an inducible in vitro microsomal mixed function oxidase (MFO) enzyme system in the marsh minnow, Fundulus heteroclitus, 7) on the presence of high MFO rates in field populations of Fundulus exosed to hydrocarbon pollution, and 8) for the synthesis into a discussion of some of the physiological reasons for the relative sensitivity of marsh animals to oil pollution and their relative ability to adapt to an oil polluted environment.
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ThesisThe escape of veligers from the egg capsules of Nassarius obsoletus and Nassarius trivittatus (gastropoda, prosobranchia)(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-06) Pechenik, Jan A.Many species of prosobranch gastropod deposit their eggs in tough capsules affixed to hard substrates. Generally, there is a small opening near the top of such capsules, occluded by a firm plug (operculum) which must be removed before the veligers can escape. Although the removal of the operculum is generally attributed to embryonic secretion of enzymes, there is little experimental support for this sugsestion. In the limited experiments which have been reported, all dealing with species that emerge as juvenile snails, no attempt was made to determine the properties of the hatching substance, or the timing of its production. My research has dealt with the escape of veligers from the egg capsules of two related species, Nassarius obsoletus and N. trivittatus. Their egg capsules are quite similar in size, number of eggs contained, general morphology, and the thickness of the material plugging the opening at the top. Both hatch as swimming veligers, after about one week of encapsulated. development. By adding fresh plug material to small volumes of sea-water containing veligers obtained prior to, or at known times after their normal hatching, I have demonstrated conclusively the essentially chemical nature of operculum removal for these two species. In addition, the hatching substance was found to be produced in a short pulse, to be functionally short-lived, and to be species-specific in its action for the two species considered. There is no evidence that the secretion of the hatching substance is stimulated by short pulses of light or increased temperature; the capsules of N. obsoletus contain many more embryos than are needed to successfully remove the plug, so that complete synchrony of hatching substance production by all individuals within a capsule is probably not necessary. Lastly, the observed rates at which N. obsoletus veligers leave their egg capsules were compared with those predicted from an equation assuming random movement of individuals. A close agreement was found, the capsules losing 98% of their residents within 45 to 55 minutes of the first escape. Thus, the location of the exit by an individual is probably by chance.
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Technical ReportBenthic fauna of the Gulf of Maine sampled by R/V Gosnold Cruise 179 and DSRV Alvin Dives 329, 330, 331, and 404 : infaunal species list(Woods Hole Oceanographic Institution, 1975-07) Rowe, Gilbert T. ; Polloni, Pamela T. ; Haedrich, Richard L.Bottom samples were collected in the Gulf of Maine during July, 1971 and June, 1972 using DSRV ALVIN and RV GOSNOLD. The techniques and results are embodied in a paper entitled "Quantitative Biological Assessment of the Benthic Fauna in the Deep Basins of the Gulf of Maine" by G. T. Rowe, P. T. Polloni and R. L. Haedrich. Many of the conclusions made in that paper were based on summaries of the abundance of each benthic species of living invertebrate animal in each kind of sample, but those original data would not be accepted by the journal (JOURNAL OF THE FISHERIES RESEARCH BOARD OF CANADA) because the table was too long. The purpose of this technical report is to put those raw data in a form available(on request from the authors)to any interested ecologists.
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ThesisEffects of high hydrostatic pressure on neuromuscular transmission in shallow-living and deep-living crustaceans(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-11) Campenot, Robert BarryThe effects of high hydrostatic pressure on excitatory neuromuscular transmission in shallow- and deep-living crustaceans were compared. Pressure caused depression of the amplitude of excitatory junctional potentials (e.j.p.s) at the neuromuscular junction in the shallow-living crab, Libinia emarginata. A pressure of 100 atm depressed the e.j.p. amplitude by about one-half. In the deep- sea crab, Geryon quinquedens, which ranges to a depth of 2000 m (or 200 atm pressure), adaptations to high pressure were observed in two different types of muscle fibers: 1) In fibers with e.j.p.s that showed high levels of facilitation, the magnitude of pressure-induced depression decreased with increasing frequency of nerve stimulation; i. e., there was a pressure-induced increase in facilitation. Also a pressure-induced increase in the duration of the falling phase of the e.j.p. was observed which served to increase the level of depolarization resulting from summation of the e.j.p.s at high frequencies of nerve stimulation. In these highly facilitating fibers the physiologically significant frequencies that cause appreciable contraction are probably high. At high frequencies the pressure-induced increases in facilitation and summation together served to completely counteract the depressive effect of pressure, and the net depolarization attained during a train of nerve stimulation was relatively unaffected by pressures up to at least 200 atm. 2) Fibers with e.j.p.s showing low levels of facilitation may undergo significant contraction at low frequencies of nerve impulses where neither facilitation nor summation play a significant role. The amplitude of e.j.p.s recorded from this fiber-type in the deep-sea crab were, on the average, unaffected by pressures to 200 atm. The e.j.p.s of some of these fibers showed depression, but others were amplified under pressure. The results of experiments with the lobster, Homarus americanus, which ranges to a depth intermediate between Libinia and Geryon were in many respects intermediate between the results obtained with the two species of crab. Studies of the effect of pressure on isometric tension developed by whole muscles in Homarus and Geryon were consistent with the results of the studies of the e.j.p.; pressure depressed the rate of rise of tension in Homarus and had little effect in Geryon. The results of this work provides a physiological basis for the observation that shallow-living animals are generally immobilized by pressures in excess of 200 atm. Experiments were performed in an attempt to elucidate the mechanism underlying the pressure-induced depression of e.j.p. amplitude. Results were suggestive that the depression of e.j.p. amplitude reflects a pressure-induced decrease in the number of quanta of transmitter substance released by the nerve endings.
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Technical ReportProject LOBSTAQ : investigations on lobster (Homarus americanus) aquaculture, ecology and tertiary sewage treatment in controlled environmental systems(Woods Hole Oceanographic Institution, 1976-04) Ryther, John H. ; Levine, Joseph S. ; Mencher, Frederick M. ; O'Neill, David J. ; Plasman, Barbara ; Star, Jeffrey ; Thielker, Jeffrey L. ; Irving, Karen ; Redmann, GregResearch was based on different aspects of incorporating Homarus Americanus cultural into the multi-trophic level marine aquaculture-wastewater treatment system of the Environmental Systems laboratory at Woods Hole. Experiments were directed .toward optimizing food sources available within the system, developing designs to facilitate high density lobster growth, and elucidating the ecology of Homarus. The aquaculture-wastewater treatment system uses secondary sewage effluent or its equivalent as a nutrient source for marine phytoplankton ponds which in turn are fed into raceways containing racks of bivalves. The bivalves produce soluble nutrients used to raise macroalgae, and solid material (biodeposits) used to raise various deposit feeders. Almost all the N and over 50% of the P is removed from the wastewater by the artificial food chain.
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ThesisOn the midwater fish faunas of Gulf Stream rings with respect to habitat differences between slope water and northern Sargasso Sea(Woods Hole Oceanographic Institution, 1976-04) Jahn, Andrew E.Forty-three 1000-in oblique Isaacs-Kidd midwater trawl collections were made on six cruises. In most cases, these were accompanied by 1500-m hydrocasts and plankton tows to 800 m. The fish collections comprise 19,400 specimens in 129 species, from Slope Water, Gulf Stream, Northern Sargasso Sea, and four cold-core rings. Temperature, salininty, oxygen, phosphate, and zooplankton biomass information accompany the collections. A model predicts that expatriate populations of Caribbean species can be maintained in the Slope Water and Northern Sargasso Sea in excess of 15 per cent of their Caribbean population density. With Caribbean contamination accounted for, the relative abundances of species in Slope Water and Northern Sargasso Sea are used to assign habitat preferences. Species clusters derived from an ordination using correspondence ana1ysis agree well with the habitat preference groups. The assemblage of species in the rings occupies the middle of a gradient in faunal composition from winter conditions in Slope Water to fall conditions in the Northern Sargasso Sea. The midwater habitat is modeled as two layers, and the ring environment as a hybrid habitat consisting of a surface layer of Northern Sargasso Sea habitat and a deep layer of Slope Water habitat. This model is consistent with patterns of species abundance. It is argued that the dramatic change in the depth of the main thermocline on crossing the Gulf Stream is the major physical factor affecting fish distributions with respect to this boundary.
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ThesisFunctional anatomy of the Macrouridae (Teleostei, Gadiformes)(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-05) McLellan, TracyOsteology and myology of the head of 21 species of macrourids and two closely related species are described. A general model of the mechanics of the macrourid head during feeding has been developed based on the anatomical findings. The structure of the head and integration of morphological units are used to explain specializations in the utilization of different food resources. Pelagic prey are the source of food for the most primitive species and for a few of the more specialized ones. A highly protrusible mouth and long rostrum are adaptations for benthic feeding and have appeared in three independent evolutionary lines within the group. Macrourids that are predators on benthos tend to be small and live at depths shallower than 2000 meters.
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ThesisNutritional ecology of Agalma okeni and other siphonophores from the epipelagic western North Atlantic Ocean(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-05) Biggs, Douglas C.The feeding and fishing behavior of siphonophores in their natural environment: was observed by SCUBA diving at 171 stations in warm-water areas of the Western North Atlantic Ocean. Calycophorae and Physonectae showed a two-phase cycle of fishing and swimming. The fishing posture of a siphonophore is determined by its floatation and by the contractility of its stem; fishing postures can be similar in siphonophores which are unrelated generically. Total tentacle length in colonies with 2 - 3 mg body protein can extend 4.5 meters. Variations in the morphology of tentilla reflect differences in the kinds of prey which can be captured. Dissection of feeding polyps revealed that most siphonophores could eat copepods, amphipods, polyc:haetes, pteropods, heteropods, veliger larvae, sergestids, mysids, euphausiids, and small fish, though laboratory experiments showed that not all could eat nauplii. Species which could capture Artemia nauplii usually required 2 - 4 hours to digest them, while large prey took 7 - 18 hours to be digested. Since a single feeding polyp of species which captured nauplii could ingest more than one per minute, colonies with 20 - 150 feeding polyps may be able to eat several hundred individuals within minutes if they encounter aggregations of small zooplankton. Agalma okeni was the most common siphonophore encountered by divers. Colonies of A. okeni maintained in the laboratory on a diet of Artemia nauplii, copepods, or shrimp budded an additional feeding polyp and 1 - 2 pairs of nectophores about every two days. Energetic calculations suggest that small and medium-size colonies incorporate 48% and 33%, respectively, of ingestion into production. A small colony of A. okeni with six nectophores probably requires 2.8 - 5.0 calories to balance daily rates of oxygen consumption and growth; a medium-size colony with 14 nectophores probably requires 5.8 - 9.2 calories. Extrapolating from short-term increases in size in the laboratory, the generation time of A. okeni in tropical and subtropical regions is likely 2 1/2 - 4 weeks. Respiration of siphonophores at 26 ± 3°C ranged from 2 - 86 μ1 02/mg protein-hr, and ammonia excretion ranged from 0.1 - 3.3 μg NH4/mg protein-hr. The cystonects Rhizophysa filiformis and Bathyphysa sibogae had low rates of respiration and excretion, while calycophores of the genus Sulculeolaria had the highest rates. For most siphonophores, ratios of oxygen consumed to ammonia-nitrogen excreted ranged from 16 - 36 and suggest that both protein and lipid are important metabolites.
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Technical ReportParticulate matter sinking to the deep-sea floor at 2000 M in the Tongue of the Ocean, Bahamas, with a description of a new sedimentation trap(Woods Hole Oceanographic Institution, 1976-09) Wiebe, Peter H. ; Boyd, Steven H. ; Winget, Clifford L.A sedimentation trap for use just above the deep-sea floor was free-fallen to a depth of 2050 m in the Tongue of the Ocean canyon on January 3, 1974. On March 6, it was successfully recovered with the assistance of D.S.R.V. Alvin. The trap has a base 1 m square and a height of 30 cm. At the trap bottom are filters to retain falling particles. Two spring-powered sliding doors, each 1 m x 0.5 m, are used to close off the lower 2 cm of the trap during ascent to prevent disturbance of the particles collected on the filters. Total carbon on the filters as determined by high temperature combustion averaged 2301 mgC/m2 or an average on a daily basis of 36.5 mgC/m2. Similar filter aliquots were treated with cold phosphoric acid to eliminate the inorganic fraction. The resulting carbon values (X =: 5.7 mgC/m2/day) suggest 14% of the total carbon reaching the sea floor at 2000 m in this area is organic in origin. Fecal material is one readily identifiable component of the material contributing to the organic fraction. Counts of fecal pellets resulted in an estimate of an average of ~650 pellets/m2/day. Average pellet length was 241 μm and diameter was 109 μm. In laboratory experiments the pellets sank at rates varying from 50 m/day to 941 m/day (X at 5°C =159 m/day). Comparison of the sedimentation trap estimates of organic carbon input to the sea floor in this area with benthic energy requirements indicates that rapidly sinking small particulate matter could supply approximately 14% of the metabolic requirements of the benthos.
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ArticleUnderwater sounds from ribbon seal, Phoca (Histriophoca) fasciata(U.S. Dept. of Commerce, NOAA, 1977) Watkins, William A. ; Ray, G. CarletonIntense downward frequency "sweeps" and broadband "puffing" sounds were recorded underwater in the presence of ribbon seal, Phoca (Histriophoca) fasciata Zimmerman 1783. The recordings were made in the waters off Savoonga, St. Lawrence Island, Alaska, on 16, 17, 18, and 23 May 1967.
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Technical ReportData report for Atlantic pelagic zoogeography(Woods Hole Oceanographic Institution, 1977-01) Backus, Richard H. ; Craddock, James E.This data report fulfils two functions. It (1) gives station data for 1022 midwater trawl collections made in the Atlantic Ocean between 1961 and 1974 by the writers and their colleagues (Table 1, Figure 1, and Appendix 1) and for 531 Atlantic neuston collections made between 1964 and 1974 (Table 2 and Appendix 2), and (2) gives the geographic coordinates for a set of boundaries that divides the Atlantic Ocean between the arctic-subarctic boundary and the subtropical convergence at 40°S into a system of faunal regions and provinces (Figure 2 and Appendix 3). The derivation of these boundaries is explained briefly.
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ThesisInvestigations into the seasonal deep chlorophyll maximum in the western North Atlantic, and its possible significande to regional food chain relationships(Woods Hole Oceanographic Institution, 1977-10) Ortner, Peter B.In many marine environments accumulations of chlorophyll have been reported to occur at or below depths to which 1% of ambient light penetrates. The phenomenon has been called the Deep Chlorophyll Maximum (DCM). On occasion zooplankton have been observed to be suggestively associated with a DCM. In order to determine, to what extent and under what circumstances, the DCM represents a significant food resource, data were obtained from vertically stratified net tows (both 0.333 μm and 0.067 μm mesh) and water bottle casts taken on eight cruises in the western North Atlantic between November 1973 and August 1976. Parameters measured included: zooplankton biomass, zooplankton functional group abundance, phytoplankton species abundance, chlorophyll concentration, ATP concentration, particulate nitrogen concentration, 14C fixation, biological macro-nutrients (N03, NO2, NH3, P04, Si(OH)4), oxygen concentration, temperature, and salinity. Parameters were measured as concommitanty as possible. Sampling was conducted in the Sargasso Sea, in Gulf Stream cold core rings, and in the Slope Water. Results obtained bear upon three major ecological problems: (a) the evolution of the biological community in a Gulf Stream cold core ring; (b) the sense in which the Gulf Stream represents an ecological discontinuity; and (c) the significance of the DCM as a locus for trophic activity. Zooplankton biomass in the upper 800 m of four Gulf Stream cold core rings significantly exceeded that in the Northern Sargasso Sea. The center of its vertical distribution was uniquely deep. Such a distribution may result in reduced ecological efficiency and increase the flux of organic matter to the deep sea. The phytoplankton assemblage of a cold core ring was significantly different from that of both the Slope Water and the Northern Sargasso Sea many months after ring formation. Certain species appeared to capitalize on some aspect of the ring environment and were especially numerous in ring samples. Due to the composition, distribution, and variability of its characteristic phytoplankton the Slope Water represented a herbivore habitat very different from that in either the Northern Sargasso Sea or a six-month-old cold core ring. Under highly stratified conditions the preceding contrast was maximal. No common species was found only on one of the other side of the Gulf Stream, yet the species could be sorted into groups that had maximal abundances either in the Slope Water or the Northern Sargasso Sea. These groups appeared to differ in their responsiveness to nutrient concentration variation. The DCM in diverse environments appeared to be an essentially identical phenomenon. The DCM accumulated phytoplankton cells (and possibly other organic particulates) sinking from above. Phytoplankton growth occurred as DCM depths despite low light levels. Various microbial processes appeared to be enhanced at DCM depths. As a consequence the DCM signalled a depth zone which, under stratified conditions, was a significant food resource especially since mixed-layer food was scarce. Concentrations of zooplankton biomass at the DCM and the vertical distributions of zooplankton functional groups indicated the DCM in the western North Atlantic was a locus of particularly intense trophic activity. The depth interval of the DCM had more total biomass and more microplankton biomass than above and below. Further, at DCM depths, the abundance of particular zooplankton functional groups appeared to reflect the size of the dominant phytoplankton. Not only presumed herbivores but a purely carnivorous group, the chaetognaths, on some occasions aggregated at DCM depths.
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ThesisRate zonal density gradient ultracentrifugation analysis of repair of radiation damage to the folded chromosome of Escherichia coli(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1978-04) Ulmer, Kevin M.The structure of the membrane-free nucleoid of Escherichia coli and of unfolded chromosomal DNA was investigated by sedimentation on neutral sucrose gradients after irradiation with 60Co gamma-rays and ultraviolet light (2S4nm). Irradiation both in vivo and in vitro was used as a molecular probe of the constraints on DNA~packaging in the bacterial chromosome. The extremely gentle lysis and unfolding procedures which were developed yielded undamaged, replicating genomes, thus permitting direct measurement of the formation and repair of DNA double-strand breaks at biologically-significant doses of ionizing radiation. In vitro UV-irradiation of nucleoids resulted in an increase in the observed rate of sedimentation due to the formation of an unknown photo-product. In contrast, UV-irradiation of wild-type cells in vivo showed evidence of the formation of incision breaks which resulted in the relaxation of supercoiling in the nucleoid. Strand breakage was also observed following in vivo UV-irradiation of a uvrB-5 strain, but at a lower rate and also accompanied by considerable unfolding of the chromosome. Such lesions may have been the result of direct photochemical reactions in the nucleoid, or enzyme activity associated with a uvr-independent mode of repair. The number of domains of supercoiling was estimated at 170 per genome equivalent of DNA based on measurements of relaxation caused by single-strand break formation in in vivo- and in vitro-gamma-irradiated folded chromosomes. Similar estimates based on the target size of RNA molecules responsible for maintaining the compact packaging of the nucleoid predicted negligible unfolding due to the formation of RNA single-strand breaks at doses up-to 10 Krad, and were born out by experimental measurements. Unfolding of the nucleoid in vitro by limit-digestion with RNase or by heating at 70° resulted in DNA complexes with sedimentation coefficients of 1030±59S and 625±15S respectively. The difference in these rates was apparently due to more complete deproteinization and thus less mass in the heated material. These structures are believed to represent intact, replicating genomes in the form of complex-theta structures containing 2-3 genome equivalents of DNA. The rate of formation of double-strand breaks was determined from molecular weight measurements of thermally unfolded chromosomal DNA gamma-irradiated in vitro. Break formation was linear with dose up to 10 Krad, resulting in 0.27 double-strand breaks per kilorad per genome equivalent of DNA and requiring 1080 eV/double-strand break. The influence of possible non-linear DNA conformations of these calculations is discussed. Repair of ionizing radiation damage to folded chromosomes was observed within 2-3 hours of post-irradiation incubation in growth medium. A model based on recombinational repair is proposed to explain the formation of 2200-2300S material during early stages of incubation and subsequent changes in the gradient profiles. Such behavior is not observed for post-irradiation incubation of wild-type cells in buffer or for a recA-13 strain incubated in growth medium. Association of unrepaired DNA with plasma membrane is proposed to explain the formation of a peak of rapidly sedimenting material (>>3100S) during the later stages of repair. Direct evidence of repair of double-strand breaks during post-irradiation incubation in growth medium was obtained from gradient profiles of DNA from RNAse-digested chromosomes. The sedimentation coefficient of broken molecules was restored to the value of unirradiated DNA after 2-3 hours of incubation, and the fraction of the DNA repaired in this fashion was equal to the fraction of cells which survived at the same dose. An average of 2.7 double-strand breaks per genome per lethal event was observed, suggesting that 1-2 double-strand breaks per genome are repairable in this strain of E. coli.