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Full-Text Articles in Life Sciences
Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow
Bacterioplankton Growth Responses To Temperature And Chlorophyll Variations In Estuaries Measured By Thymidine:Leucine Incorporation Ratio, Fk Shiah, Hw Ducklow
VIMS Articles
To identify the biochemical response of heterotrophic bacterioplankton to changing environmental conditions, seasonal and diel cycles of bacterial protein and DNA synthesis rates were estimated in temperate estuarine habitats from H-3-leucine (Leu) and H-3-thymidine (TdR) incorporation rates. Several short-term temperature manipulation experiments (5 to 35 degrees C) and 2 mesocosm experiments were performed to examine the effects of temperature and substrate supply on the ratio of Leu:TdR, respectively. The molar ratio of Leu to TdR varied about 5-fold (5.6 to 29.5) in the field and the values of the ratio were lower and more constant during high temperature (>25 …
Phenotypic Plasticity In The Foot Size Of An Intertidal Snail, Gc Trussell
Phenotypic Plasticity In The Foot Size Of An Intertidal Snail, Gc Trussell
VIMS Articles
The risk of dislodgment due to hydrodynamic forces on rocky intertidal shores is greater on wave-exposed than an protected shores, and this:is believed to represent an important selective force in intertidal communities. For intertidal snails, the probability of dislodgment by a given flow is determined, in part, by shell size and shape, and by the attachment strength of the foot. This study addressed two questions. First, do habitat-specific differences in traits that reduce the risk of dislodgment of an intertidal snail(Littorina obtusata) parallel differences in wave energies? To address this question, I measured variation in (1) shell size (defined as …
Investigating The Management Potential Of A Seagrass Model Through Sensitivity Analysis And Experiments, P Fong, Me Jacobson, Mc Mescher, D Lirman, Mc Harwell
Investigating The Management Potential Of A Seagrass Model Through Sensitivity Analysis And Experiments, P Fong, Me Jacobson, Mc Mescher, D Lirman, Mc Harwell
VIMS Articles
Loss of seagrass-dominated ecosystems worldwide has been attributed to anthropogenic modifications of watersheds; in response, proper management of these systems has become a priority. In this paper, sensitivity analysis and comparison of model predictions to field observations identified conditions under which a subtropical to tropical seagrass ecosystem model would be a useful management tool. Sensitivity analysis indicated that under low-nutrient conditions, physical factors such as temperature, light, and salinity controlled model predictions of seagrass and epiphyte biomass, but that when nutrients were abundant (5 mu mol/L sediment pore water P; 10 mu mol/L water column P) control shifted to biological …
Settlement Site Selection By Oyster Larvae, Crassostrea Virginica: Evidence For Geotaxis, Patrick Baker
Settlement Site Selection By Oyster Larvae, Crassostrea Virginica: Evidence For Geotaxis, Patrick Baker
VIMS Articles
Settlement of larval oysters, Crassostrea virginica, with respect to upper and lower surfaces of natural substrates, was studied in the field and in the laboratory. Enclosures were used to retain pediveligers of Crassostrea under controlled field conditions: until they settled. About 62% of these larvae settled onto rough (outer) surfaces of natural oyster shell substrate; this closely marched the proportion of substrate oriented with the rough surface downward. In the laboratory, about 83% of larvae settled onto the lower surfaces of similar shell substrates, in the absence of light, regardless of how the shell substrate was positioned. Both field and …
Development Of A Process-Based Nitrogen Mass Balance Model For A Virginia (Usa) Spartina Alterniflora Salt Marsh: Implications For Net Din Flux, Iris C. Anderson, Cr Tobias, Bb Neikirk, Rl Wetzel
Development Of A Process-Based Nitrogen Mass Balance Model For A Virginia (Usa) Spartina Alterniflora Salt Marsh: Implications For Net Din Flux, Iris C. Anderson, Cr Tobias, Bb Neikirk, Rl Wetzel
VIMS Articles
Primary production is nitrogen limited in most salt marshes with the possible exception of those impacted by high anthropogenic inputs of nitrogen. It is hypothesized that mature salt marshes which receive only small inputs of 'new' nitrogen from the atmosphere, surface water runoff, groundwater, tidal creek, and nitrogen-fixation will have a conservative nitrogen cycle. We have developed a process-based N mass balance model for a short-term Spartina alterniflora marsh in Virginia, USA. Data for the model included rates of gross mineralization, nitrification, denitrification, nitrogen fixation, above- and belowground macrophyte production, and benthic microalgal production. The annual balance between sources (mineralization, …