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Articles 2731 - 2760 of 3959

Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology

Crop Updates 2004 - Cereals, Wal Anderson, Vivian Vanstone, Rob Loughman, Vanessa Stewart, Darshan Sharma, Christine M. Zaicou-Kunesch, Brenda Shackley, Mohammad Amjad, Steve Penny Jr, Glen Riethmuller, Jeremy Lemon, Mario D'Antuono, Veronika Reck, Ben Curtis, Judith Devenish, Melaine Kupsch, Anne Smith, Blakely Paynter, Roslyn J. Jettner, Leanne Schulz, Jocelyn Ball, Tom Sweeny, Stephen Loss, Ashleigh Brooks, Justin Fuery, Geoff Anderson, Zed Rengel, Paul Damon, Eddy Pol, Narelle Hill, Ray Tugwell, Ron Mctaggart, Nathan Moyes, John Majewski, Manisha Shankar, James Piotrowski, Ciara Beard, Kithsiri Jayasena, Kazue Tanaka, Grey Poulish, Debbie Thackray, Rohan Prince, Roger Jones, Peter Nelson, Nigel Metz, Leisa Armstrong, Yee Leong (Alex) Yung, Moin U. Salam, David Tennant Feb 2004

Crop Updates 2004 - Cereals, Wal Anderson, Vivian Vanstone, Rob Loughman, Vanessa Stewart, Darshan Sharma, Christine M. Zaicou-Kunesch, Brenda Shackley, Mohammad Amjad, Steve Penny Jr, Glen Riethmuller, Jeremy Lemon, Mario D'Antuono, Veronika Reck, Ben Curtis, Judith Devenish, Melaine Kupsch, Anne Smith, Blakely Paynter, Roslyn J. Jettner, Leanne Schulz, Jocelyn Ball, Tom Sweeny, Stephen Loss, Ashleigh Brooks, Justin Fuery, Geoff Anderson, Zed Rengel, Paul Damon, Eddy Pol, Narelle Hill, Ray Tugwell, Ron Mctaggart, Nathan Moyes, John Majewski, Manisha Shankar, James Piotrowski, Ciara Beard, Kithsiri Jayasena, Kazue Tanaka, Grey Poulish, Debbie Thackray, Rohan Prince, Roger Jones, Peter Nelson, Nigel Metz, Leisa Armstrong, Yee Leong (Alex) Yung, Moin U. Salam, David Tennant

Crop Updates

This session covers twenty eight papers from different authors:

PLENARY

1. Declining profitability in continuous cropping systems. Is more wheat the answer on Duplex soil? Dr Wal Anderson, Department of Agriculture

2. Disease implications of extending the wheat phase in low-medium rainfall areas, Dr Vivian Vanstone and Dr Robert Loughman, Department of Agriculture

3. Prolonged wheat phase on duplex soils – where do weeds set the boundary? Vanessa Stewart, Department of Agriculture

WHEAT AGRONOMY

4. Management of small grain screenings in wheat, Dr Wal Anderson and Dr Darshan Sharma, Department of Agriculture

5. Agronomic responses of new wheat varieties, Christine …


New Species Of Eustomias (Teleostei: Stomiidae) From The Western North Atlantic, With A Review Of The Subgenus Neostomias, Tracey Sutton, Karsten E. Hartel Feb 2004

New Species Of Eustomias (Teleostei: Stomiidae) From The Western North Atlantic, With A Review Of The Subgenus Neostomias, Tracey Sutton, Karsten E. Hartel

Marine & Environmental Sciences Faculty Articles

A new species of the deep-sea dragonfish genus Eustomias is described from 14 specimens from the western North Atlantic. This species belongs to the subgenus Neostomias, which is defined principally by the presence of a single pectoral ray, plus one small rudimentary ray. It is unique among members of the subgenus in having a combination of characters that includes a short mental barbel, multiple proximal bulbs on the barbel main stem, and a unique terminal bulb morphology. Analysis of similar species warrants resurrection of Eustomias monodactylus, previously placed in synonymy with Eustomias filifer. A revised key to …


Trophic Ecology Of The Deep-Sea Fish Malacosteus Niger (Pisces: Stomiidae): An Enigmatic Feeding Ecology To Facilitate A Unique Visual System?, Tracey Sutton Feb 2004

Trophic Ecology Of The Deep-Sea Fish Malacosteus Niger (Pisces: Stomiidae): An Enigmatic Feeding Ecology To Facilitate A Unique Visual System?, Tracey Sutton

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

The ‘dragonfishes’ and their relatives (family Stomiidae) are among the top predators of the mesopelagic zone of the open ocean. Based on feeding morphology (e.g., large gape, long fangs, and no gill-rakers or ethmoid membrane), the meso/bathypelagic fish Malacosteus niger would also be expected to be a large-item predator, as are the other members of its family. However, analysis of specimens from different ocean basins revealed that the most common prey items are calanoid copepods, despite an apparent inability to handle such small prey. Malacosteus niger is considered advanced within the Stomiidae, so this feeding mode represents a secondary reversion …


Predicting Biodiversity Patterns In Deep Water Coral Ecosystems: Lessons From Phylogenetic Studies Of Shallow Water Coral Reef Crustacea, James Darwin Thomas Feb 2004

Predicting Biodiversity Patterns In Deep Water Coral Ecosystems: Lessons From Phylogenetic Studies Of Shallow Water Coral Reef Crustacea, James Darwin Thomas

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Comprehensive studies of coral reef biodiversity suggest that diversity patterns may be more congruent with geotectonic events than with the reigning paradigms of dispersal, center of origin, and vicariance. Geotectonic processes slowly accumulate taxa in areas exemplified by the presence of composite or lineage-based evolutionary diversity. This process-pattern model can suggest additional areas where similar patterns are likely to occur. Information on types and levels of diversity should be a primary concern in emerging conservation efforts for deepwater coral ecosystems. Current marine conservation efforts in shallow reef systems rely primarily on identifying “hotspots” that reflect measures of species richness and …


Interactions Between Zooplankton And Karenia Brevis In The Gulf Of Mexico., Kristen M. Lester, Gabriel A. Vargo, John J. Walsh, Cynthia A. Heil, Mary B. Neely, Danylle N. Spence, Susan Murasko, Tracey Sutton, Scott E. Burghart, Andrew Remsen, T. L. Hopkins, Richard N. Bohrer Feb 2004

Interactions Between Zooplankton And Karenia Brevis In The Gulf Of Mexico., Kristen M. Lester, Gabriel A. Vargo, John J. Walsh, Cynthia A. Heil, Mary B. Neely, Danylle N. Spence, Susan Murasko, Tracey Sutton, Scott E. Burghart, Andrew Remsen, T. L. Hopkins, Richard N. Bohrer

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Blooms of the toxic dinoflagellate K. brevis are common in the Gulf of Mexico, yet no in situ studies of the interactions between zooplankton and K. brevis in the Gulf of Mexico have been conducted. Zooplankton numerical abundance, biomass and taxonomic composition of nonbloom and K. brevis bloom stations within the ECOHAB study area were compared. At nonbloom stations, the most important determinant species were Parvolcalanus crassirostris, Oithona colcarva and Paracalanus quasimodo at the 5-m isobath and P. quasimodo, O. colcarva and Oikopleura dioka at the 25-m isobath. There was considerable overlap between the 5 and 25-m isobaths, with …


Development Of Gis Maps For Southeast Florida Coral Reefs, Bernhard Riegl, Brian K. Walker, Ryan P. Moyer, Luz Hernandez-Cruz, Greg Foster, Christy Foster Jan 2004

Development Of Gis Maps For Southeast Florida Coral Reefs, Bernhard Riegl, Brian K. Walker, Ryan P. Moyer, Luz Hernandez-Cruz, Greg Foster, Christy Foster

Marine & Environmental Sciences Faculty Reports

The present report outlines the results of an integrated mapping project undertaken to provide a habitat map of the shallow Broward County seafloor between the 0m and 35m contour. The study area stretched from Golden Beach in northern Dade County to just north of the Palm Beach County line. To produce this map and assure its compatibility with other, in particular NOAA, mapping products, a series of data were integrated. Data types included Laser Airborne Depth Sounder (LADS) bathymetry, multi- and single-beam bathymetry, acoustic seafloor discrimination, ecological assessments, and groundtruthing. The method used for acoustic seafloor discrimination was based on …


Nitrogen Transport Through Linked Stream-Lake Systems Measured With N Tracer, Wayne A. Wurtsbaugh, Koren Nydick, Michelle A. Baker, Bob Hall Jan 2004

Nitrogen Transport Through Linked Stream-Lake Systems Measured With N Tracer, Wayne A. Wurtsbaugh, Koren Nydick, Michelle A. Baker, Bob Hall

Watershed Sciences Faculty Publications

No abstract provided.


Biozonation On Deep-Water Carbonate Mounds And Associated Hardgrounds Along The Western Margin Of Little Bahama Bank, With Notes On The Caicos Platform Island Slope, Charles G. Messing Jan 2004

Biozonation On Deep-Water Carbonate Mounds And Associated Hardgrounds Along The Western Margin Of Little Bahama Bank, With Notes On The Caicos Platform Island Slope, Charles G. Messing

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Carbonate mounds found in a broad band from about 325 to 700 m along the western margin of Little Bahama Bank exhibit consistent faunal zonations characterized by assemblages of attached, suspension-feeding macroinvertebrates dominated by sponges, octocorals, crinoids and stylasterid and scleractinian corals. Biozonation on hard substrates appears chiefly dependent on depth (and associated parameters, e.g., temperature) and current flow. Mounds in 325-435 m with up to 30 m vertical relief reveal dense assemblages on gentler up current slopes and flanks, and an almost complete lack of macrofauna on steep downcurrent slopes. Macrofauna include stalked crinoids on upcurrent slopes and crest, …


Spatial And Temporal Recruitment Patterns Of Juvenile Grunts (Haemulon Spp.) In South Florida, L. K. B. Jordan, David S. Gilliam, Robin L. Sherman, Paul T. Arena, Fleur M. Harttung, Robert M. Baron, Richard E. Spieler Jan 2004

Spatial And Temporal Recruitment Patterns Of Juvenile Grunts (Haemulon Spp.) In South Florida, L. K. B. Jordan, David S. Gilliam, Robin L. Sherman, Paul T. Arena, Fleur M. Harttung, Robert M. Baron, Richard E. Spieler

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Grunts (Haemulidae) are important fisheries species and represent a major component of reef fish communities in the Greater Caribbean region. To date, little is known about their recruitment pattems. Data from more than 2,000 visual fish counts from multiple natural and artificial reef studies in Broward County, Florida, over a seven-year period, were examined to identify both spatial and temporal trends in recruitment of juvenile (i.e., < 5cm TL) grunts of the genus Haemulon. In general, data from these studies indicate that juvenile Haemulon spp. recruitment increases in the spring and peaks in the early summer months (i.e., June and July). Data from natural reef surveys revealed a predominantly nearshore preference for recruitment in water depths less than 8 m. However, on artificial reefs, recruitment commoniy occurred at 20 m depths. The biotic and abiotic factors determining the settlement of grunts are not clear and will be examined in future studies.


Presence Of Juvenile Blackfin Snapper, Lutjanus Buccanella, And Snowy Grouper, Epinephelus Niveatus, On Shallow-Water Artificial Reefs, Paul T. Arena, Patrick Quinn, Lance K. B. Jordan, Robin L. Sherman, Fleur M. Harttung, Richard E. Spieler Jan 2004

Presence Of Juvenile Blackfin Snapper, Lutjanus Buccanella, And Snowy Grouper, Epinephelus Niveatus, On Shallow-Water Artificial Reefs, Paul T. Arena, Patrick Quinn, Lance K. B. Jordan, Robin L. Sherman, Fleur M. Harttung, Richard E. Spieler

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

The inshore environment of Broward County, Florida consists of three reef tracts, each separated by sand substrate, running parallel to the coastline in sequentially deeper water. A wide variety of artificial reef designs have been deployed in Broward County, many lying in sand flats between the reeftracts. From 1995 through 2002, over 1,100 visual fish censuses (predominantly point-counts) were completed on the three natural reeftracts in water depths from 3 m to 30 m and over 1,100 censuses were done on artificial reefs at depths of 7 m to 23 m. Curiously, the juvenile stages of two deeper-water species of …


Habitat Preferences And Diving Behavior Of White Marlin (Tetrapturus Albidus) Released From The Recreational Rod-And-Reel And Commercial Pelagic Longline Fisheries In The Western North Atlantic Ocean: Implications For Habitat-Based Stock Assessment Models, Andrij Horodysky, David W. Kerstetter, John E. Graves Jan 2004

Habitat Preferences And Diving Behavior Of White Marlin (Tetrapturus Albidus) Released From The Recreational Rod-And-Reel And Commercial Pelagic Longline Fisheries In The Western North Atlantic Ocean: Implications For Habitat-Based Stock Assessment Models, Andrij Horodysky, David W. Kerstetter, John E. Graves

Marine & Environmental Sciences Faculty Reports

To improve billfish assessments, researchers have applied habitat-based models that incorporate behavioral and oceanographic parameters to standardize historical catch-per-uniteffort time -series data, accounting for significant gear changes over time. However, there has been little behavioral data from Atlantic billfishes to support these models. We provide information on habitat preferences of white marlin released from recreational and commercial fisheries in the western North Atlantic. White marlin were tagged with pop-up satellite archival tags (PSATs) from recreational rod and reel (n=22) and commercial pelagic longline (n=2) fisheries between May-November 2002. Our data indicate that each surviving white marlin spent the majority of …


Sea Turtle Conservation Program, Broward County, Fl 2004 Report, Curtis M. Burney, Stefanie Ouellette Jan 2004

Sea Turtle Conservation Program, Broward County, Fl 2004 Report, Curtis M. Burney, Stefanie Ouellette

Marine & Environmental Sciences Faculty Reports

No abstract provided.


Microfauna As Tracers Of Sediment Transport: Ft. Pierce Dredge Spoils Sediment Study, Patricia Blackwelder, Carlos Alvares Zarikian, Terry Hood, Charles M. Featherstone, John Proni, Jules Craynock Jan 2004

Microfauna As Tracers Of Sediment Transport: Ft. Pierce Dredge Spoils Sediment Study, Patricia Blackwelder, Carlos Alvares Zarikian, Terry Hood, Charles M. Featherstone, John Proni, Jules Craynock

Marine & Environmental Sciences Faculty Reports

No abstract provided.


Diel Activity Patterns, Space Utilization, Seasonal Distribution And Population Structure Of The Yellow Stingray, Urobatis Jamaicensis (Cuvier, 1817) In South Florida With Comments On Reproduction., Daniel P. Fahy Jan 2004

Diel Activity Patterns, Space Utilization, Seasonal Distribution And Population Structure Of The Yellow Stingray, Urobatis Jamaicensis (Cuvier, 1817) In South Florida With Comments On Reproduction., Daniel P. Fahy

HCNSO Student Theses and Dissertations

The yellow stingray, Urobatis jamaicensis is the most common elasmobranch in the coastal waters of Southeast Florida. Despite their common occurrence the ecology of yellow stingrays remains poorly understood. In particular, yellow stingray daily movements, space utilization, seasonal distribution and population structure have not been described. This study was conducted to address the lack of knowledge of these fundamental life history parameters and to provide further information on the ecology of U. jamaicensis in coastal waters of Broward County, Florida.

The activity patterns and space utilization of U. jamaicensis were assessed by manual tracking with ultrasonic telemetry. Telemetry tracking of …


Light Dependence Of Selenium Uptake By Phytoplankton And Implications For Predicting Selenium Incorporation Into Food Webs, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter, Lynda S. Cutter, Brian Cole Jan 2004

Light Dependence Of Selenium Uptake By Phytoplankton And Implications For Predicting Selenium Incorporation Into Food Webs, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter, Lynda S. Cutter, Brian Cole

OES Faculty Publications

The potentially toxic element selenium is first concentrated from solution to a large but highly variable degree by algae and bacteria before being passed on to consumers. The large loads of abiotic and detrital suspended particles often present in rivers and estuaries may obscure spatial and temporal patterns in Se concentrations at the base of the food web. We used radiotracers to estimate uptake of both selenite (Se(IV)) and C by intact plankton communities at two sites in the Sacramento/San Joaquin River Delta. Our goals were to determine (1) whether C and Se(IV) uptake were coupled, (2) the role of …


Analytical Intercomparison Between Flow Injection-Chemiluminescence And Flow Injection-Spectrophotometry For The Determination Of Picomolar Concentrations Of Iron In Seawater, Andrew R. Bowie, Peter N. Sedwick, Paul J. Worsfold Jan 2004

Analytical Intercomparison Between Flow Injection-Chemiluminescence And Flow Injection-Spectrophotometry For The Determination Of Picomolar Concentrations Of Iron In Seawater, Andrew R. Bowie, Peter N. Sedwick, Paul J. Worsfold

OES Faculty Publications

A lab- and ship-based analytical intercomparison of two flow injection methods for the determination of iron in seawater was conducted, using three different sets of seawater samples collected from the Southern Ocean and South Atlantic. In one exercise, iron was determined in three different size-fractions (< 0.03 &μm, < 0.4 μm, and unfiltered) in an effort to better characterize the operational nature of each analytical technique with respect to filter size. Measured Fe concentrations were in the range 0.19 to 1.19 nM using flow injection with luminol chemiluminescence detection (FI-CL), and 0.07 to 1.54 nM using flow injection with catalytic spectrophotometric detection with N, N-dimethyl-p-phenylenediamine dihydrochloride (FI-DPD). The arithmetic mean for the FI-CL method was higher (by 0.09 nM) than the FI-DPD method for dissolved (< 0.4 μm) Fe, a difference that is comparable to the analytical blanks, which were as high as 0.13 nM ( CL) and 0.09 nM (DPD). There was generally good agreement between the FI-CL determinations for the < 0.03 μm size fraction and the FI-DPD determinations for the < 0.4 μm size fraction in freshly collected samples. Differences in total-dissolvable ( unfiltered) Fe concentrations determined by the two FI methods were more variable, reflecting the added complexity associated with the analysis of partially digested particulate material in these samples. Overall, however, the FI-CL determinations were significantly (P = 0.05) lower than the FI-DPD determinations for the unfiltered samples. Our results suggest that the observed, systematic inter-method differences reflect measurement of different physicochemical fractions of Fe present in seawater, such that colloidal and/or organic iron species are better determined by the FI-CL method than the FI-DPD method. This idea is supported by our observation that inter-method differences were largest for freshly collected acidified seawater, which suggests extended storage (>6 months) of acidified samples as a possible protocol for the determination of dissolved iron in seawater.


Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann Jan 2004

Influence Of Short-Term Variations In Food On Survival Of Crassotrea Gigas Larvae: A Modeling Study, Eric N. Powell, Eleanor A, Bochenek, John M. Klinck, Eileen E. Hofmann

OES Faculty Publications

A biochemically-based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster, Crassostrea gigas. The model defines larvae in terms of their protein, lipid, carbohydrate, and ash content and includes variation in growth efficiency and egg quality to better simulate cohort population dynamics. Changes in tissue composition occur as the larva grows and in response to the biochemical composition of the food. The premise behind this modeling study was that certain periods of larval life are more critical than others with respect to the availability of food and that food quality is as …


Physical Forcing Of Phytoplankton Community Structure And Primary Production In Continental Shelf Waters Of The Western Antarctic Peninsula, Barbara B. Prézelin, Eileen E. Hofmann, Mark Moline, John M. Klinck Jan 2004

Physical Forcing Of Phytoplankton Community Structure And Primary Production In Continental Shelf Waters Of The Western Antarctic Peninsula, Barbara B. Prézelin, Eileen E. Hofmann, Mark Moline, John M. Klinck

OES Faculty Publications

Analyses of a multidisciplinary data set, collected in continental shelf waters of the Western Antarctic Peninsula (WAP) during austral summer of January 1993, identified a previously unrecognized forcing mechanism that sets up a physical and chemical structure that supports and assures site-specific diatom-dominated communities and enhanced biological production (Prézelin et al., 2000). This forcing is active when the southern boundary of the Antarctic Circumpolar Current (ACC) flows along the shelf edge, thereby facilitating onshelf bottom intrusions of nutrient-rich Upper Circumpolar Deep Water (UCDW), which then is upwelled or mixed into the upper water column. At times or locations where UCDW …


Black Carbon In Estuarine And Coastal Ocean Dissolved Organic Matter, Antonio Mannino, H. Rodger Harvey Jan 2004

Black Carbon In Estuarine And Coastal Ocean Dissolved Organic Matter, Antonio Mannino, H. Rodger Harvey

OES Faculty Publications

We measured black carbon (BC) in ultrafiltered, high-molecular weight dissolved organic matter (UDOM) in surface waters of Delaware Bay, Chesapeake Bay, and the adjacent Atlantic Ocean (U.S.A.) to investigate the importance of riverine and estuarine dissolved organic matter (DOM) as a source of BC to the ocean. BC was 5-72% of UDOM-C (27 ± 17%), which corresponds to 8.9 ± 6.5% of dissolved organic carbon (DOC), with higher values in the heavily urbanized midbay region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of …


Relevant Scales In Zooplankton Ecology: Distribution, Feeding, And Reproduction Of The Copepod Acartia Hudsonica In Response To Thin Layers Of The Diatom Skeletonema Costatum, Alexander B. Bochdansky, Stephen M. Bollens Jan 2004

Relevant Scales In Zooplankton Ecology: Distribution, Feeding, And Reproduction Of The Copepod Acartia Hudsonica In Response To Thin Layers Of The Diatom Skeletonema Costatum, Alexander B. Bochdansky, Stephen M. Bollens

OES Faculty Publications

We investigated the interaction of the copepod Acartia hudsonica in relation to thin layers of the diatom Skeletonema costatum. Thin layers have recently received much attention, since they are common and persistent features in the water column, often overlooked by traditional sampling methods. Their frequent abundance in coastal oceans and the high biomass associated with them has led to the assumption that they are important grazing sites of calanoid copepods. We employed 2-m tall tower tanks that allowed us to simulate thin layers. Three variables representative of three time scales were considered: the distribution of copepods in the tanks …


Interactive Regulation Of Dissolved Copper Toxicity By An Estuarine Microbial Community, Christina L. Dryden, Andrew S. Gordon, John R. Donat Jan 2004

Interactive Regulation Of Dissolved Copper Toxicity By An Estuarine Microbial Community, Christina L. Dryden, Andrew S. Gordon, John R. Donat

OES Faculty Publications

Cultured marine microorganisms under copper stress produce extracellular compounds having a high affinity for copper (copper-complexing ligands). These ligands are similar in binding strength to those found in natural waters, but few studies have examined the relationship between copper, copper-complexing ligand concentrations, and natural microbial populations. A series of in situ experiments in the Elizabeth River, Virginia, revealed that an intact estuarine microbial community responded to copper stress by production of extracellular, high-affinity copper-complexing ligands. The rate of ligand production was dependent on copper concentration and resulted in a reduction of the concentration of free cupric ions, Cu2+, …


Age And Growth Of Scotia Sea Icefish, Chaenocephalus Aceratus, From The South Shetland Islands, M. La Mesa, J. Ashford, E. Larson, M. Vacchi Jan 2004

Age And Growth Of Scotia Sea Icefish, Chaenocephalus Aceratus, From The South Shetland Islands, M. La Mesa, J. Ashford, E. Larson, M. Vacchi

OES Faculty Publications

Samples of Chaenocephalus aceratus (Lönnberg) were collected during a trawl survey carried out around the South Shetland Islands in January–February 2002. Fish were caught by commercial bottom trawl fishing down to 500 m depth, using a stratified randomized sampling design. As observed in other recent surveys within the same area, C. aceratus represented one of the predominant species. Overall, 357 specimens ranging from 13 and 67 cm (TL) were selected for the present study. Ages were estimated by counting annuli present in the sagittal otoliths, exposed by grinding and polishing along their sagittal plane. To estimate the precision of age …


Dinitrogen Fixation And Release Of Ammonium And Dissolved Organic Nitrogen By Trichodesmium Ims101, Margaret R. Mulholland, Deborah A. Bronk, Douglas G. Capone Jan 2004

Dinitrogen Fixation And Release Of Ammonium And Dissolved Organic Nitrogen By Trichodesmium Ims101, Margaret R. Mulholland, Deborah A. Bronk, Douglas G. Capone

OES Faculty Publications

Two methods used to measure dinitrogen (N2) fixation (acetylene reduction and 15N2 uptake) often result in different N2 fixation rates. Part of the discrepancy may arise from the observation that Trichodesmium can release a fraction of their recently fixed N2 as dissolved organic nitrogen (DON) and/or ammonium (NH4 +). To resolve outstanding issues regarding N2 fixation and the production of dissolved combined nitrogen (N) by Trichodesmium, we conducted a comprehensive analysis of N2 fixation and the production of DON and NH4+ in cultures of Trichodesmium IMS101. We performed …


Winter 2004, Nsu Oceanographic Center Jan 2004

Winter 2004, Nsu Oceanographic Center

Currents

No abstract provided.


Summer 2004, Nova Southeastern University Jan 2004

Summer 2004, Nova Southeastern University

Currents

No abstract provided.


Advection, Krill, And Antarctic Marine Ecosystems, Eileen E. Hofmann, Eugene J. Murphy Jan 2004

Advection, Krill, And Antarctic Marine Ecosystems, Eileen E. Hofmann, Eugene J. Murphy

CCPO Publications

Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC) provides a connection between most parts of the system, including open ocean and continental shelf regions. The ACC also provides a mechanism for large-scale transport of plankton, such as Antarctic krill (Euphousia superba Dana), which is an important component of the Southern Ocean food web. This overview provides a summary of recent observational and modelling results that consider the importance of advection to the Southern Ocean ecosystem and, in particular, …


Method Analysis Of Laboratory Measures Of Stream Sediment And Water Phosphorus Equilibrium, Anna L. Erickson, Stephanie M. Williamson, Brian E. Haggard Jan 2004

Method Analysis Of Laboratory Measures Of Stream Sediment And Water Phosphorus Equilibrium, Anna L. Erickson, Stephanie M. Williamson, Brian E. Haggard

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Elevated phosphorus concentrations in aquatic ecosystems of northwest Arkansas prompted an investigation of the effects of sample preparation and extraction methods on laboratory measures of sediment-phosphorus interactions. Two streams of contrasting phosphorus (P) concentrations were selected to determine the effect of using a CaCl2 solution instead of filtered stream water, refrigerated or dried sediments instead of fresh wet sediments, and vortexing the suspensions instead of shaking them. Sediment equilibrium P concentration (EPC0) and P buffering capacity (K) were used to determine differences in extraction methods. EPC0 and K from extractions using fresh sediments and a CaCl2 solution matching the electrical …


Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin Jan 2004

Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

The University of Arkansas Crop, Soil, and Environmental Sciences (CSES) Club adopted a local wetland in the spring of 2002 through the Fayetteville Parks and Recreation Department. This project has allowed students to interact with local community and governmental organizations as well as other academic departments within the university. Students have gained valuable laboratory and field experience through characterizing hydric soils, identifying bird and plant species, and analyzing water quality, soil nutrients, and microbial biomass. Under the main goal of restoring the wetland, the club has outlined both short and long-term objectives including soil and water assessments; removal of two …


A Modelling Study Of The Influence Of Environment And Food Supply On Survival Of Crassostrea Gigas Larvae, Eileen E. Hofmann, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck Jan 2004

A Modelling Study Of The Influence Of Environment And Food Supply On Survival Of Crassostrea Gigas Larvae, Eileen E. Hofmann, Eric N. Powell, Eleanor A. Bochenek, John M. Klinck

CCPO Publications

A biochemically based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster (Crassostrea gigas). The unique characteristics of the model are that it: (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate, and ash content; (2) tracks weight separately from length to follow larval condition; and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for filtration, ingestion, and respiration, which determine larval growth rate, and processes controlling larval mortality and metamorphosis. Changes in larval tissue …


Lagrangian Modelling Studies Of Antarctic Krill (Euphausia Superba) Swarm Formation, Eileen E. Hofmann, A. G. Edward Haskell, John M. Klinck, Cathy M. Lascara Jan 2004

Lagrangian Modelling Studies Of Antarctic Krill (Euphausia Superba) Swarm Formation, Eileen E. Hofmann, A. G. Edward Haskell, John M. Klinck, Cathy M. Lascara

CCPO Publications

A two-dimensional Lagrangian particle model was developed to examine the spatial distribution of Antarctic krill (Euphausia superba). The time-dependent location of particles, which represent krill individuals, is determined by random diffusion, foraging activity, and movement induced by the presence of neighbours. Foraging activity is based on prescribed food conditions and is such that krill swim slower and turn more frequently in areas of high food concentration. The presence or absence of neighbours either disperses krill, if the local concentrations become too dense, or coalesces krill, if concentrations become too dilute, respectively. Predation on krill is included and affects …