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Articles 31 - 60 of 61
Full-Text Articles in Life Sciences
Microscale Patchiness Of Bacterioplankton Assemblage Richness In Seawater, Richard A. Long, Farooq Azam
Microscale Patchiness Of Bacterioplankton Assemblage Richness In Seawater, Richard A. Long, Farooq Azam
Faculty Publications
We sought to test the hypothesis that bacterial species richness and composition vary at the millimeter scale in the marine pelagic environment, in response to the heterogeneous distribution of organic matter. To test this hypothesis, it was necessary to design and test a protocol to sample, lyse and analyze (by polymerase chain reaction/denaturing gradient gel electrophoresis [PCR-DGGE]) bacterioplankton species richness in a single microliter of seawater. Significant variation in bacterial species richness was found amongst 1 μl samples. Greater species richness was seen when seawater was enriched with diatom detritus. Examination of species richness at 2 mm intervals over a …
Variations In Bacterial Community Structure During A Dinoflagellate Bloom Analyzed By Dgge And 16s Rdna Sequencing, Laura B. Fandino, Lasse Riemann, Grieg F. Steward, Richard A. Long, Farooq Azam
Variations In Bacterial Community Structure During A Dinoflagellate Bloom Analyzed By Dgge And 16s Rdna Sequencing, Laura B. Fandino, Lasse Riemann, Grieg F. Steward, Richard A. Long, Farooq Azam
Faculty Publications
The relationship between bacterial 16S rRNA gene composition and carbon metabolism was analyzed during an intense dinoflagellate bloom off the Southern California coast during the spring of 1997. Bacterial numbers and rate processes, chlorophyll a, and the dissolved and particulate organic matter pools were measured during the bloom to provide a framework within which to assess bacterial community composition. Free bacteria were numerically dominant, generally comprising >90% of the total, and were responsible for >70% of bacterial production. Attached bacteria had higher cell-specific growth rates than free bacteria (range = 0.5 to 15.1 and 0.7 to 2.5 d-1 …
Effect Of Harvest And Effective Population Size On Genetic Diversity In A Striped Bass Population, Marilyn Diaz, David S. Wethey, James Bulak, Bert Ely
Effect Of Harvest And Effective Population Size On Genetic Diversity In A Striped Bass Population, Marilyn Diaz, David S. Wethey, James Bulak, Bert Ely
Faculty Publications
A major factor that contributes to loss of genetic variation in natural populations is a small effective population size. In species with a complex life history that involves overlapping generations and delayed maturity, the impact of infrequent annual reproductive bottlenecks is likely to be small because effective population size is defined by the number of individuals contributing to a generation and not to a single year-class. The striped bass Morone saxatilis is a longlived species with overlapping generations and age structure, whose recreational and commercial importance has made it a target of intense harvest.We analyzed allele frequency fluctuation among juvenile …
Responses Of Phytoplankton And Pfiesteria-Like Dinoflagellate Zoospores To Nutrient Enrichment In The Neuse River Estuary, North Carolina, Usa, James L. Pinckney, Hans W. Paerl, Elin Haugen, Patricia A. Tester
Responses Of Phytoplankton And Pfiesteria-Like Dinoflagellate Zoospores To Nutrient Enrichment In The Neuse River Estuary, North Carolina, Usa, James L. Pinckney, Hans W. Paerl, Elin Haugen, Patricia A. Tester
Faculty Publications
The recently described toxic dinoflagellate Pfiestena piscicida and morphologically similar Pfiesteria-like dinoflagellates have become a major water quality issue with possible fish mortality and reported human health implications. The linkages between accelerated nutrient loading, eutrophication, and the proliferation of this group of dinoflagellates, however, are not well established for natural Systems. Phytoplankton pnmary production may provide a key link between nutrient inputs and potential outbreaks of Pfiesteria-like biflagellated zoospores in the Neuse River Estuary, North Carolina. The impacts of nutrient (NO3- -nitrogen and PO43- -phosphorus) supply rates, sediment-water column exchange, water column mixing, and phytoplankton prey …
Nutrient Cycling In The Water Column Of A Subtropical Seagrass Meadow, Susan Ziegler, Ronald Benner
Nutrient Cycling In The Water Column Of A Subtropical Seagrass Meadow, Susan Ziegler, Ronald Benner
Faculty Publications
The cycling of nutrients was studied over a 16 mo period to determine how processes occurring between the water column and benthos influenced nutrient dynamics in a Thalassia testudinum dominated seagrass meadow. Nutrient concentrations were low and ranged from below detection to 0.59 µM ammonium (NH4+), 0.04 to 0.29 µM nitrate plus nitrite (NO3- + NO2-), and below detection to 0.22 µM soluble reactive phosphate (SRP). Water column and benthic fluxes of NO3- + NO2- and SRP were usually below detection. The benthic fluxes of NH4+ …
Fish Kills And Bottom-Water Hypoxia In The Neuse River And Estuary: Reply To Burkholder Et Al., Hans W. Paerl, James L. Pinckney, John M. Fear, Benjamin L. Peierls
Fish Kills And Bottom-Water Hypoxia In The Neuse River And Estuary: Reply To Burkholder Et Al., Hans W. Paerl, James L. Pinckney, John M. Fear, Benjamin L. Peierls
Faculty Publications
No abstract provided.
Film Formation By Marine Bacteria At A Model Fluid Interface, Vera Zutic, Nadica Ivosevic, Vesna Svetlicic, Richard A. Long, Farooq Azam
Film Formation By Marine Bacteria At A Model Fluid Interface, Vera Zutic, Nadica Ivosevic, Vesna Svetlicic, Richard A. Long, Farooq Azam
Faculty Publications
We have characterized the nonspecific interactions in the initial attachment and film formation by marine bacteria at a dynamic fluid interface: seawater/dropping mercury electrode. Experimental evidence is presented that bacteria readily establish molecular contact with the metal substrate without mediation of a conditioning film. Prevalence of hydrophobic over electrostatic interactions and the possible importance of Ca2+ bridging could be inferred. The attachment of individual bacterial cells is faster than their transport from the aqueous medium, as is the case in the transport-controlled adsorption of biopolymers. The cell aggregates yield distinct electrical attachment signals, allowing a comparison between cell-cell and …
Dissolved Organic Carbon Cycling In A Subtropical Seagrass-Dominated Lagoon, Susan Ziegler, Ronald Benner
Dissolved Organic Carbon Cycling In A Subtropical Seagrass-Dominated Lagoon, Susan Ziegler, Ronald Benner
Faculty Publications
The cycling of dissolved organic matter (DOM) and its significance to ecosystem metabolism was studled over a 16 mo period in a Thalassia testudjnum dominated meadow. The benthos was usually net autotrophic (annual gross primary production to respiration ratio [P:R] = 1.3) while water column respiration (R) exceeded gross primary production (annual P:R = 0.3). Net fluxes of dissolved organic carbon (DOC) from the benthos primarily occurred in the light (0 to 18 mmol C m-2 d-1) and from seagrass-dominated areas, suggesting that release of DOC was mainly due to seagrass exudation. Net benthic DOC fluxes measured …
Coupling Between Bacterioplankton Species Composition, Population Dynamics, And Organic Matter Degradation, Jarone Pinhassi, Farooq Azam, Johanna Hemphälä, Richard A. Long, Josefina Martinez, Ulla Li Zweifel, Åke Hagström
Coupling Between Bacterioplankton Species Composition, Population Dynamics, And Organic Matter Degradation, Jarone Pinhassi, Farooq Azam, Johanna Hemphälä, Richard A. Long, Josefina Martinez, Ulla Li Zweifel, Åke Hagström
Faculty Publications
To study the effect of substrate addition on short term bacterial population dynamics and species composition in seawater mesocosms were maintained with water collected off Scripps Pier (La Jolla, California USA) Protein enrichment (BSA) triggered a dynamic response from the microbial food web, whereas enrichment with starch had no effect. In the protein enriched mesocosm the number of both nucleoid-containing cells and metabolically active cells increased by 3.0 X 105 cells ml-1 from Day 1 to Day 4 In the same time period the density of a set of 31 phylogenetically different bacteria (α- and g-Proteobactena as well …
Rainfall Stimulation Of Primary Production In Western Atlantic Ocean Waters: Roles Of Different Nitrogen Sources And Co-Limiting Nutrients, Hans W. Paerl, Joan D. Willey, Malia Go, Benjamin L. Peierls, James L. Pinckney, Marilyn L. Fogel
Rainfall Stimulation Of Primary Production In Western Atlantic Ocean Waters: Roles Of Different Nitrogen Sources And Co-Limiting Nutrients, Hans W. Paerl, Joan D. Willey, Malia Go, Benjamin L. Peierls, James L. Pinckney, Marilyn L. Fogel
Faculty Publications
Using shipboard bioassays, we examined the roles rainfall, individual and combined nutrients play in accelerating primary production in coastal, Gulf Stream and pelagic (Sargasso Sea) locations in the North Atlantic Ocean off North Carolina, USA, from 1993 to 1995. Photosynthetic CO2 fixation and net chlorophyll a (chl a) production were measured In replicated bioassays to assess individual and combined impacts of different constituents of atmospheric deposition, including natural rainfall, a synthetic rain mix, dissolved inorganic nitrogen (DIN; NH4+ ,NO3-), dissolved organic nitrogen (DON; urea),phosphorus (PO43-) and iron (as EDTA-chelated and …
Ecosystem Metabolism In A Subtropical Seagrass-Dominated Lagoon, Susan Ziegler, Ronald Benner
Ecosystem Metabolism In A Subtropical Seagrass-Dominated Lagoon, Susan Ziegler, Ronald Benner
Faculty Publications
Measurements of ecosystem gross primary production (GPP) and respiration (R) were made for 2 to 3 consecutive days on 10 occasions from February 1996 through June 1997 in the seagrass-dominated Laguna Madre (Texas, USA). Ecosystem GPP and R were quantified using 3 independent measurements including the open-water technique using dissolved oxygen (DO) and dissolved inorganic carbon (DIC) and the summation of discrete measurements of the water column and benthos. Diel curves of DIC were often influenced by water movement while the impact of water movement on DO was not apparent. This was attributed to the longer turnover time of DIC …
Ecosystem Responses To Internal And Watershed Organic Matter Loading: Consequences For Hypoxia In The Eutrophying Neuse River Estuary, North Carolina, Usa, Hans W. Paerl, James L. Pinckney, John M. Fear, Benjamin L. Peierls
Ecosystem Responses To Internal And Watershed Organic Matter Loading: Consequences For Hypoxia In The Eutrophying Neuse River Estuary, North Carolina, Usa, Hans W. Paerl, James L. Pinckney, John M. Fear, Benjamin L. Peierls
Faculty Publications
The contrasting impacts of externally supplied (runoff) and internally generated (nutrient stimulated phytoplankton blooms) organic matter on oxygen (02) depletion were examined and evaluated in the eutrophic, salinity-stratified Neuse River Estuary, North Carolina, USA. This nitrogen (N)- limited estuary is experiencing increasing anthropogenic N loading from expanding urban, agricultural and industrial development in its watershed. Resultant algal blooms, which provided organic matter loads capable of causing extensive low 02 (hypoxic) and depleted 02 (anoxic) conditions, have induced widespread mortality of resident fin- and shellfish. Phytoplankton blooms followed periods of elevated N loading, except during extremely high …
A Transcription-Dependent Switch Controls Competence Of Adult Neurons For Distinct Modes Of Axon Growth, Deanna S. Smith, J.H. Pate Skene
A Transcription-Dependent Switch Controls Competence Of Adult Neurons For Distinct Modes Of Axon Growth, Deanna S. Smith, J.H. Pate Skene
Faculty Publications
Although maturing neurons undergo a precipitous decline in the expression of genes associated with developmental axon growth, structural changes in axon arbors occur in the adult nervous system under both normal and pathological conditions. Furthermore, some neurons support extensive regrowth of long axons after nerve injury. Analysis of adult dorsal root ganglion (DRG) neurons in culture now shows that competence for distinct types of axon growth depends on different patterns of gene expression. In the absence of ongoing transcription, newly isolated neurons can extend compact, highly branched arbors during the first day in culture. Neurons subjected to peripheral axon injury …
Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin
Modeling Interactions Of Browsing Predation, Infaunal Activity And Recruitment In Marine Soft-Sediment Habitats, Sara M. Lindsay, David S. Wethey, Sarah A. Woodin
Faculty Publications
In marine soft-sediment habitats, the sediment surface is altered by activities of sediment dwellers (infauna). Such biogenic disturbance can influence recruitment success if settling larvae and juveniles avoid disturbed sites or if juveniles die as a result of disturbance after settling. Because infauna commonly lose exposed body parts to browsing predators and disturb less sediment as a result, we developed a simulation model to examine the interactions between browsing predation, infaunal adult activity, and recruitment. Sediment disturbance in the model was based on data for the polychaete Abarenicola pacifica. We simulated the activity of two general types of predators: prey …
Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam
Abundant Protein-Containing Particles In The Sea, Richard A. Long, Farooq Azam
Faculty Publications
The interaction of bacteria with particulate organic matter has implications for organic matter cycling and bacterial ecology in the ocean. Until recently, the focus has been on 'classical' particles visible by unaided eye (marine snow) or light microscopy. Recent discoveries of several new types of abundant particles, from sub-micrometer to sub-marine snow, are changing our ideas of the physical and chemical nature of the particle field with which pelagic bacteria interact. Previous workers have discovered polysaccharide-containing (Alcian Blue stainable) transparent exopolymer particles (TEP) ranging from 3 to 100s of micrometers. Looking for additional components of the sub-marine snow particle field, …
Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey
Settlement And Early Post-Settlement Survival Of Sessile Marine Invertebrates On Topographically Complex Surfaces: The Importance Of Refuge Dimensions And Adult Morphology, Linda J. Walters, David S. Wethey
Faculty Publications
We predicted that both refuge dimension and growth form would influence settlement and short-term post-settlement success (≤7 d) of sessile marine invertebrates that live attached to hard substrata in low energy environments. Individuals with unlimited attachment to the substrata should rapidly be protected by their growth form, thus decreasing their need to settle in refuges and limiting the length of time any locations on heterogeneous substrata act as refuges. Alternatively, organisms with limited attachment to the substrata should remain susceptible to the causes of mortality for a longer time, and as a result should settle in high quality refuges (sites …
Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson
Effects Of High-Molecular-Weight Dissolved Organic Matter On Nitrogen Dynamics In The Mississippi River Plume, Wayne S. Gardner, Ronald Benner, Rainer M.W. Amon, James B. Cotner Jr., Joann F. Cavaletto, Jeffrey R. Johnson
Faculty Publications
The dynamics of N and its interactions with labile dissolved organic C (DOC), bacteria, and phytoplankton were studied to determine potential effects of dissolved organic matter (DOM) and light on N dynamics in surface waters of the Mississippi River (USA) plume in the Gulf of Mexico. Bacterial uptake of added labeled N compounds ( 15NH4+ or 15N-labeled dissolved free amino acids. DFAA) was stimulated more by high-molecular-weight (HMW, >l kDa) DOM than by low-molecular-weight (LMW, < l kDa) DOM. An index that inversely indicated the presence of labile DOC was defined as the fraction of assimilated Amino acid-15N that was Recovered as 15N -Ammonium (ANRA), following the additions of high-levels (4 µM) of 15N -DFAA. …
Impacts Of Seasonality And Nutrients On Microbial Mat Community Structure And Function, James L. Pinckney, Hans W. Paerl, M. Fitzpatrick
Impacts Of Seasonality And Nutrients On Microbial Mat Community Structure And Function, James L. Pinckney, Hans W. Paerl, M. Fitzpatrick
Faculty Publications
To understand the mechanisms responsible for seasonal fluctuations in growth and N2 fixation in intertidal microbial mat communities, we quantified seasonal changes in mat community composition, related these changes to diel and seasonal N2 fixation rates, and evaluated community responses (growth, N2fixation, composition) to long-term (22 d) nutrient addition bioassays. A temperate intertidal cyanobacterial mat community, located in coastal North Carolina, USA, was sampled at monthly intervals for 1 yr (1993-94) to determine changes in community composition. The abundances of major phototrophic groups were quantified based on the relative concentrations of taxaspecific photopigments (chlorophylls and carotenoids). …
Community Metabolism And Nutrient Cycling In The Mississippi River Plume: Evidence For Intense Nitrification At Intermediate Salinities, Joseph D. Pakulski, Ronald Benner, Rainer Amon, Brian Eadie, Terry Whitledge
Community Metabolism And Nutrient Cycling In The Mississippi River Plume: Evidence For Intense Nitrification At Intermediate Salinities, Joseph D. Pakulski, Ronald Benner, Rainer Amon, Brian Eadie, Terry Whitledge
Faculty Publications
Community respiration, net nutrient fluxes and heterotrophic bacterial production were investigated in the Mississippi River (USA) plume during May 1992 using dark bottle incubations of unfiltered water. Highest rates of community O2 consumption and dissolved inorganic carbon regeneration were observed at intermediate (10 to 27%0) plume salinities. Plume surface 02 consumption rates were 2- to 4-fold greater than rates reported previously during the summer and winter. Heterotrophic bacterial production ([3H]-leucine incorporation) was also highest at intermediate salinities and 2- to 4-fold greater than rates reported from other seasons. Net regeneration of NH4+ …
Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner
Denitrification, Nutrient Regeneration And Carbon Mineralization In Sediments Of Galveston Bay, Texas, Usa, Andrew R. Zimmerman, Ronald Benner
Faculty Publications
Rates of benthic denitrification, oxygen consumption and nutrient regeneration were measured during winter, spring and summer in Galveston Bay (Texas, USA) sediments. Denitrification ranged from 0 to 47 µmol N2 m-2 h-1 with maximal rates generally occurring in the summer and the upper estuary. Oxygen consumption rates ranged from 38 µmol O2 m-2 h-1 in the winter to 353 µmol O2 m-2 h-1 in the summer and were correlated with denitrification rates. Variations in bay water temperature accounted for 52 % of the variability associated with denitrification rates whereas only 28% …
Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher
Activity And Distribution Of Attached Bacteria In Chesapeake Bay, Peter Griffith, Fuh-Kwo Shiah, Kathryn Gloersen, Hugh W. Ducklow, Madilyn Fletcher
Faculty Publications
The purpose of this study was to further our understanding of the role of particle-associated bacteria in phytoplankton degradation in the Chesapeake Bay, USA, and to identify environmental parameters that control production by free and particle-associated bacteria. Surface and bottom waters at 10 stations along the length of the Bay were sampled over a 2 yr period. Samples were analyzed for temperature, salinity, chlorophyll, phaeophytin, particulate protein, thymidine incorporation (an estimate of bacterial growth rate), and bacterial total direct counts. Results demonstrated that freeliving bacteria were responsible for most of the total bacterial production, which was correlated with temperature and …
Decomposition Of Senescent Blades Of The Seagrass Halodule Wrightii In A Subtropical Lagoon, Stephen Opsahl, Ronald Benner
Decomposition Of Senescent Blades Of The Seagrass Halodule Wrightii In A Subtropical Lagoon, Stephen Opsahl, Ronald Benner
Faculty Publications
Senescent blades from the seagrass Halodule wrightii Aschers were suspended in the water column of Laguna Madre (Texas, USA) for a period of 419 d, representing the longest seagrass decomposition study to date. The initial stage of decomposition was characterized by a rapid loss of organic matter (36 % in 24 d) attributed to leaching. A total of 76 % of the organic matter from seagrass tissues was lost by the end of the decomposition period. Of the major bulk constituents measured, neutral sugars were most abundant and accounted for 23 % of the ash-free dry wt of the initial …
Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner
Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner
Faculty Publications
Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N2 m-2 h-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N2 m-2 h-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O2 m-2 h-1 in Nueces Estuary and from 208 to 550 µmol O2 …
Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell
Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell
Faculty Publications
Sediment cores were collected inside and outside of a bed of a bromophenol-producing marine polychaete, Notomastus lobatus, and examined for impact of the bromophenols on sediment microflora and meiofauna around N. lobatus burrows. No significant differences were found between microbial parameters measured inside and outside of the N. lobatus bed. Integrated 6 cm cores taken adjacent to N. lobatus burrows contained 1.2 x 109 bacteria ml-1. Cell numbers were similar at control sites within the bed, but away from burrows, and not significantly different from cell numbers (1.0 X 109 cells ml-1) at a …
Enhanced Bacterioplankton Production And Respiration At Intermediate Salinities In The Mississippi River Plume, Gerardo Chin-Leo, Ronald Benner
Enhanced Bacterioplankton Production And Respiration At Intermediate Salinities In The Mississippi River Plume, Gerardo Chin-Leo, Ronald Benner
Faculty Publications
Bacterial abundance and production (thymidine and leucine incorporation) were measured along a salinity gradient from the Mississippi River (0 %0) to the open waters of the Gulf of Mexico (36 %0) during July-August 1990 and February 1991. Bacterial production in surface waters was maximal at intermediate salinities (15 to 30 %0). Nutrient enrichment experiments suggested that bacterial growth near the outflow of the river was C limited whereas bacteria in plume waters of intermediate salinities were P and N limited. Rates of plankton community oxygen demand measured during winter were also maximal at intermediate …
Effects Of Tidal Stage And Sun Angles On Intertidal Benthic Microalgal Productivity, James L. Pinckney, R. G. Zingmark
Effects Of Tidal Stage And Sun Angles On Intertidal Benthic Microalgal Productivity, James L. Pinckney, R. G. Zingmark
Faculty Publications
Motile benthic diatoms exhibit rhythmic vertical migrations that are influenced by tidal and light cycles. As a consequence of these periodic migrations, corresponding periodicities in benthic microalgal production should occur. Using oxygen microelectrodes, hourly measurements of microalgal production were obtained from subaerially exposed cores collected from low-intertidal muddy sediments in North Inlet estuary, South Carolina, USA Microalgal productivity at low tide was twice that at high tide (mean difference 52 %) and was significantly correlated with diurnal and tidal periodicities (r2 = 0.41; p < 0.0001). Production values ranged from 28.0 to 460.5 µmol O2 mg chl a-1 h-1 and maximum rates were achieved during mid-afternoon low …
Dynamics Of Bacterioplankton Abundance And Production In Seagrass Communities Of A Hypersaline Lagoon, Gerardo Chin-Leo, Ronald Benner
Dynamics Of Bacterioplankton Abundance And Production In Seagrass Communities Of A Hypersaline Lagoon, Gerardo Chin-Leo, Ronald Benner
Faculty Publications
The significance of bacterioplankton in the flow of carbon and energy and in trophic dynamics of the upper Laguna Madre, Texas (USA), was estimated by measuring bacterioplankton abundance and production over an 18 mo period and over several diel cycles. Bacterioplankton production was estimated from incorporation rates of thymidine (DNA synthesis) and leucine (protein synthesis). These independent inhces of bacterial growth were generally in agreement and yielded nearly identical annual estimates of bacterial production (25.24 g C m-2 yr-1 based on thymidine and 25.12 g C m-2 yr-1based on leucine). Assuming a 30 % growth …
Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney
Age And Growth Of King Mackerel, Scomberomorus Cavalla, From The Atlantic Coast Of The United States, Mark R. Collins, David J. Schmidt, C. Wayne Waltz, James L. Pinckney
Faculty Publications
Whole sagittae from 683 and sectioned sagittae from 773 "adult" (age> 0 ; 437-1.310 mm FL), and lapilli from 29 larval (2-7 mm SL) and 69 young-of-the-year (79-320 mm FL) king mackerel, were examined. All fish were from waters off the Atlantic coast of the southeastern United States (Cape Canaveral, Florida to Cape Fear. North Carolina). Back-calculated lengths at ages and von Bertalanffy growth equations were calculated from both whole and sectioned sagittae. Ages determined from sectioned sagittae were significantly greater than ages determined from whole sagittae, and the magnitude of the difference increased with age (from sections). Rings on …
Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters
Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters
Faculty Publications
A method is presented that allows rapid and accurate measurement of changes in the spatial pattern of space occupation in encrusting organisms. The boundaries of organisms are represented as polygons, and geometric difference calculations are used to establish the perimeters of the areas gained or vacated between sampling dates. The influence of interspecific interactions on occupation of space is also quantified: geometric intersection calculations are used to define the perimeters of the areas gained or lost in overgrowth interactions. A method is presented for estimating the sampling frequency necessary for detection of significant changes in occupation of space. The method …
Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson
Microbial Degradation Of The Leachable And Lignocellulosic Components Of Leaves And Wood From Rhizophora Mangle In A Tropical Mangrove Swamp, Ronald Benner, Robert E. Hodson
Faculty Publications
Preparations of uniformly [14C] labeled mangrove leaves and specifically radiolabeled [14C-lignin] lignocelluloses and [14C -polysaccharide]lignocelluloses from mangrove leaves and wood were used in experiments to determine the microbial rates of mineralization of the leachable and lignocellulosic components of mangrove detritus in aerobic and anaerobic sediments of a tropical mangrove swamp. The bulk of the leachable fraction from mangrove leaves was mineralized relatively rapidly and was assimilated into microbial biomass with high efficiency (30 %). In contrast, rates of mineralization of the lignocellulosic component of mangrove leaves and wood were 10fold lower than mineralization rates …