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Full-Text Articles in Biology
Long-Term Monitoring And Analyses Of Physical Factors Regulating Variability In Coastal Antarctic Phytoplankton Biomass, In Situ Productivity And Taxonomic Composition Over Subseasonal, Seasonal And Interannual Time Scales, Mark A. Moline, Barbara B. Prezelin
Long-Term Monitoring And Analyses Of Physical Factors Regulating Variability In Coastal Antarctic Phytoplankton Biomass, In Situ Productivity And Taxonomic Composition Over Subseasonal, Seasonal And Interannual Time Scales, Mark A. Moline, Barbara B. Prezelin
Biological Sciences
A 3 yr high-resolution temporal data base related to phytoplankton dynamics was collected during the austral spring/summer periods of 1991 to 1994 in shelf waters adjacent to Palmer Station, Antarctica. Here, the data base is used (1) to quantify the variability in phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales; (2) to elucidate environmental mechanisms controlling these temporal patterns; and (3) to ascertain which phytoplankton markers are most suitable for detecting longer-term (i.e. decadal) trends in phytoplankton dynamics in coastal waters of the Southern Ocean. The Long-Term Ecological Research (LTER) coastal study sites …
Genetic And Social Control Of Male Maturation In Phallichthys Quadripunctatus (Pisces: Poeciliidae), Gita R. Kolluru, David N. Reznick
Genetic And Social Control Of Male Maturation In Phallichthys Quadripunctatus (Pisces: Poeciliidae), Gita R. Kolluru, David N. Reznick
Biological Sciences
Age and size at maturity can have significant fitness consequences. Selection often favors early-maturing individuals because of their higher survival to maturity and greater relative contribution to population growth rate, but it may also favor delayed maturation if fitness increases with age or size at maturity. Males of several poeciliid fishes exhibit variation in age and size at maturity primarily controlled by a sex-linked gene called the P-locus. Wild-caught Phallichthys quadripunctatus males show a bimodal size distribution, which is often associated with a P-locus polymorphism in other poeciliids. We conducted two experiments to evaluate the inheritance of male age and …
High-Resolution Time-Series Data For 1991/1992 Primary Production And Related Parameters At A Palmer Lter Coastal Site: Implications For Modeling Carbon Fixation In The Southern Ocean, Mark A. Moline, Barbara B. Prezelin
High-Resolution Time-Series Data For 1991/1992 Primary Production And Related Parameters At A Palmer Lter Coastal Site: Implications For Modeling Carbon Fixation In The Southern Ocean, Mark A. Moline, Barbara B. Prezelin
Biological Sciences
Our goal was to provide a high-resolution temporal data base for modeling primary production in shelf waters adjacent to Palmer Station, Antarctica. Here, the resulting 1991/1992 data base is used to: (1) determine in situ productivity over a range of seasonal to subseasonal time scales; (2) identify time scales of significant variability in marine productivity during the peak growing season; (3) identify environmental, experimental and analytical factors that can significantly impact the accuracy of daily, weekly and seasonal productivity estimates; and (4) integrate our findings with previous studies of Antarctic coastal primary pro- duction. Data were gathered every 2–3 days …
Azorhizobium Caulinodans Uses Both Cytochrome Bd (Quinol) And Cytochrome Cbb3 (Cytochrome C) Terminal Oxidases For Symbiotic N2 Fixation, Alexandre Kaminski, Christopher L. Kitts, Zachary Zimmerman, Robert A. Ludwig
Azorhizobium Caulinodans Uses Both Cytochrome Bd (Quinol) And Cytochrome Cbb3 (Cytochrome C) Terminal Oxidases For Symbiotic N2 Fixation, Alexandre Kaminski, Christopher L. Kitts, Zachary Zimmerman, Robert A. Ludwig
Biological Sciences
Azorhizobium caulinodans employs both cytochrome bd (cytbd; quinol oxidase) and cytcbb3 (cytc oxidase) as terminal oxidases in environments with very low O2 concentrations. To investigate physiological roles of these two terminal oxidases both in microaerobic culture and in symbiosis, knockout mutants were constructed. As evidenced by visible absorbance spectra taken from mutant bacteria carrying perfect gene replacements, both the cytbd- and cytcbb3- mutations were null alleles. In aerobic culture under 2% O2 atmosphere, Azorhizobium cytbd- and cytcbb3- single mutants both fixed N2 at 70 to 90% of wild-type rates; in root nodule symbiosis, both single mutants fixed N2 at 50% …
Two Erroneous, Commonly Cited Examples Of "Swordfish" Piercing Wooden Ships, Harry L. Fierstine, Oliver Crimmen
Two Erroneous, Commonly Cited Examples Of "Swordfish" Piercing Wooden Ships, Harry L. Fierstine, Oliver Crimmen
Biological Sciences
No abstract provided.
Use Of Rostral Characters For Identifying Adult Billfishes (Teleostei: Perciformes: Istiophoridae And Xiphiidae), Harry L. Fierstine, Nicole L. Voigt
Use Of Rostral Characters For Identifying Adult Billfishes (Teleostei: Perciformes: Istiophoridae And Xiphiidae), Harry L. Fierstine, Nicole L. Voigt
Biological Sciences
Seven species of the family Istiophoridae and Xiphias gladiu6 were identified using only features of their rostrum. In the Istiophoridae, two rostral regions were emphasized, one-fourth and one·half the distance between the distal tip and the orbital margin of the lateral ethmoid bone. Characters studied in each region were the depth and width of rostrum and height, width, and position of nutrient canals (as seen in cross-section). Characters studied without reference to region were the distribution of denticles on both dorsal and ventral surfaces of the bilI and position of the prenasal bone. In the Xiphiidae, the only characters studied …
Trade-Offs In Parasitology, Evolution And Behavior, Marlene Zuk, M. J. Bryant, Gita R. Kolluru, V. Mirmovitch
Trade-Offs In Parasitology, Evolution And Behavior, Marlene Zuk, M. J. Bryant, Gita R. Kolluru, V. Mirmovitch
Biological Sciences
No abstract provided.
Light-Saturated Primary Production In Antarctic Coastal Waters, Mark A. Moline, Barbara B. Prezelin, Herve Claustre
Light-Saturated Primary Production In Antarctic Coastal Waters, Mark A. Moline, Barbara B. Prezelin, Herve Claustre
Biological Sciences
No abstract provided.
Temporal Dynamics Of Coastal Antarctic Phytoplankton: Environmental Driving Forces And Impact Of 1991/92 Summer Diatom Bloom On The Nutrient Regimes, Mark A. Moline, Barbara B. Prezelin, Oscar Schofield, Raymond C. Smith
Temporal Dynamics Of Coastal Antarctic Phytoplankton: Environmental Driving Forces And Impact Of 1991/92 Summer Diatom Bloom On The Nutrient Regimes, Mark A. Moline, Barbara B. Prezelin, Oscar Schofield, Raymond C. Smith
Biological Sciences
Within the Palmer Long Term Ecological Research Program (PAL-LTER), a suite of environmental data sets were collected at a nearshore station throughout the 1991/92 austral summer. Seasonal changes are presented in the context of phytoplankton community ecology. Subseasonal fluctuations in sea-ice coverage, freshwater inputs, as well as wind driven and advective processes disrupting stratified surface waters, appeared to be the major driving forces affecting the timing, duration and demise of local phytoplankton blooms. During a large diatom-dominated bloom (~30 mg chl a m-3), macronutrients were depleted to detection limits (NO3--3, PO4-3< 0.03 mmol m-3) …
Effect Of Larval Swimming Duration On Success Of Metamorphosis And Size Of The Ancestrular Lophophore In Bugula Neritina (Bryozoa), Dean E. Wendt
Effect Of Larval Swimming Duration On Success Of Metamorphosis And Size Of The Ancestrular Lophophore In Bugula Neritina (Bryozoa), Dean E. Wendt
Biological Sciences
There is a growing realization that events during one portion of an organism's life cycle can have both subtle and dramatic effects on other stages in the life history. Lethal and sublethal effects associated with the duration of larval swimming in marine invertebrates were examined for the bryozoan Bugula neritina. Larvae were kept swimming up to a maximum of 28 h at 20{deg}C by exposure to continuous bright fluorescent illumination. At 4-h intervals, samples of 20-40 larvae were removed from bright illumination and were exposed to seawater containing 10 mM excess KCI, an inducer of metamorphosis in this species. …
Analysing Ancient Dna, Raúl J. Cano
Analysing Ancient Dna, Raúl J. Cano
Biological Sciences
Much of what we know about extinct organisms comes from traits that are not preserved in the fossil record. Until recently, morphological analysis was the only tool available for scientists to determine relationships for extinct fossil organisms. We now know that ‘ancient’ DNA can be preserved in the remains of extinct organisms. By targeting specific gene sequences, it may be possible to deduce biochemical characteristics and through sequence comparisons, to estimate the extent of evolutionary divergence. By comparing the amount and type of these changes, one could estimate how quickly some DNA ‘evolves’ relative to other segments, or which genes …