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- Photosynthesis (4)
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- Climate change (2)
- Community structure (2)
- Dinoflagellates (2)
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- Otolith chemistry (2)
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- Age pigment (1)
- Alga blooms (1)
- Algae (1)
- Alosa sapidissima (1)
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- Analysis (1)
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Articles 1 - 26 of 26
Full-Text Articles in Fresh Water Studies
Acidification Of Northeastern Usa Lakes From Rising Anthropogenic-Sourced Atmospheric Carbon Dioxide And Its Effects On Aluminum Speciation, Karen H. Johannesson, Jaxon Dii Horne, Anant Misra, Catherine Aliperta, Orpheus V. Meletis, Robert C. Santore, Christopher D. White, Georgia Mavrommati, David J. Burdige
Acidification Of Northeastern Usa Lakes From Rising Anthropogenic-Sourced Atmospheric Carbon Dioxide And Its Effects On Aluminum Speciation, Karen H. Johannesson, Jaxon Dii Horne, Anant Misra, Catherine Aliperta, Orpheus V. Meletis, Robert C. Santore, Christopher D. White, Georgia Mavrommati, David J. Burdige
OES Faculty Publications
The impact of rising atmospheric CO2 (pCO2atm) from anthropogenic activities on pH, dissolved inorganic carbon, carbonate mineral saturation, and aluminum (Al) speciation is evaluated for 18 northeastern USA lakes using polythermal, sliding activity reaction path models. pCO2atm was forced using two scenarios from the IPCC's Sixth Assessment Report in which pCO2atm attains either 600 or 1,100 ppm in 2,100. Results suggest pH will decrease 0.15 and 0.32 pH units, aCO2-3 will decrease 24% and 49%, and Ωaragonite will decrease 21% and 45%, respectively. These changes are of the same …
Present And Future Thermal Regimes Of Intertidal Groundwater Springs In A Threatened Coastal Ecosystem, Jason J. Karrisallen, Aaron A. Mohammed, Joseph Tamborski, Rob C. Jamieson, Serban Danielescu, Barret L. Kurylyk
Present And Future Thermal Regimes Of Intertidal Groundwater Springs In A Threatened Coastal Ecosystem, Jason J. Karrisallen, Aaron A. Mohammed, Joseph Tamborski, Rob C. Jamieson, Serban Danielescu, Barret L. Kurylyk
OES Faculty Publications
In inland settings, groundwater discharge thermally modulates receiving surface water bodies and provides localized thermal refuges; however, the thermal influence of intertidal springs on coastal waters and their thermal sensitivity to climate change are not well studied. We addressed this knowledge gap with a field- and model-based study of a threatened coastal lagoon ecosystem in southeastern Canada. We paired analyses of drone-based thermal imagery with in situ thermal and hydrologic monitoring to estimate discharge to the lagoon from intertidal springs and groundwater-dominated streams in summer 2020. Results, which were generally supported by independent radon-based groundwater discharge estimates, revealed that combined …
Bomb Radiocarbon Age Validation For The Long-Lived, Unexploited Arctic Fish Species Coregonus Clupeaformis, John M. Casselman, Cynthia M. Jones, Steven E. Campana
Bomb Radiocarbon Age Validation For The Long-Lived, Unexploited Arctic Fish Species Coregonus Clupeaformis, John M. Casselman, Cynthia M. Jones, Steven E. Campana
OES Faculty Publications
The growth rates of freshwater fish in the Arctic would be expected to be very low, but some previous studies of lake whitefish (Coregonus clupeaformis) have reported relatively rapid growth and longevity estimates of less than 15 years. We used bomb radiocarbon chronologies to validate an ageing method based on otolith sections for lake whitefish in both an unexploited Arctic lake (MacAlpine Lake; longevity 50 years) and a lightly exploited temperate population (Lake Simcoe; longevity 49 years). Our results confirm previous suggestions that other ageing methods can seriously underestimate lake whitefish age after ~5–8 years. A Chapman–Robson estimate …
Patterns Of Diatom Diversity Correlate With Dissolved Trace Metal Concentrations And Longitudinal Position In The Notheast Pacific Coastal Offshore Transition Zone, P. Dreux Chappell, E. Virginia Armbrust, Katherine A. Barbeau, Randelle M. Bundy, Jagruti Vedamati, Bethany D. Jenkins
Patterns Of Diatom Diversity Correlate With Dissolved Trace Metal Concentrations And Longitudinal Position In The Notheast Pacific Coastal Offshore Transition Zone, P. Dreux Chappell, E. Virginia Armbrust, Katherine A. Barbeau, Randelle M. Bundy, Jagruti Vedamati, Bethany D. Jenkins
OES Faculty Publications
Diatoms are important primary producers in the northeast Pacific Ocean, with their productivity closely linked to pulses of trace elements in the western high nitrate, low chlorophyll (HNLC) region of the oceanographic time series transect 'Line P.' Recently, the coastal-HNLC transition zone of the Line P transect was identified as a hotspot of phytoplankton productivity, potentially controlled by a combination of trace element and macronutrient concentrations. Here we describe diatom community composition in the eastern Line P transect, including the coastal- HNLC transition zone, with a method using high-throughput sequencing of diatom 18S gene amplicons. We identified significant correlations between …
Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman
Ebullition Of Oxygen From Seagrasses Under Supersaturated Conditions, Matthew H. Long, Kevin Sutherland, Scott D. Wankel, David J. Burdige, Richard C. Zimmerman
OES Faculty Publications
Gas ebullition from aquatic systems to the atmosphere represents a potentially important fraction of primary production that goes unquantified by measurements of dissolved gas concentrations. Although gas ebullition from photosynthetic surfaces has often been observed, it is rarely quantified. The resulting underestimation of photosynthetic activity may significantly bias the determination of ecosystem trophic status and estimated rates of biogeochemical cycling from in situ measures of dissolved oxygen. Here, we quantified gas ebullition rates in Zostera marina meadows in Virginia, U.S.A. using simple funnel traps and analyzed the oxygen concentration and isotopic composition of the captured gas. Maximum hourly rates of …
Blooms Of Dinoflagellate Mixotrophs In A Lower Chesapeake Bay Tributary: Carbon And Nitrogen Uptake Over Diurnal, Seasonal, And Interannual Timescales, Margaret R. Mulholland, Ryan Morse, Todd Egerton, Peter W. Bernhardt, K. C. Filippino
Blooms Of Dinoflagellate Mixotrophs In A Lower Chesapeake Bay Tributary: Carbon And Nitrogen Uptake Over Diurnal, Seasonal, And Interannual Timescales, Margaret R. Mulholland, Ryan Morse, Todd Egerton, Peter W. Bernhardt, K. C. Filippino
OES Faculty Publications
A multi-year study was conducted in the eutrophic Lafayette River, a sub-tributary of the lower Chesapeake Bay during which uptake of inorganic and organic nitrogen (N) and C compounds was measured during multiple seasons and years when different dinoflagellate species were dominant. Seasonal dinoflagellate blooms included a variety of mixotrophic dinoflagellates including Heterocapsa triquetra in the late winter, Prorocentrum minimum in the spring, Akashiwo sanguinea in the early summer, and Scrippsiella trochoidea and Cochlodinium polykrikoides in late summer and fall. Results showed that no single N source fueled algal growth, rather rates of N and C uptake varied on seasonal …
Origins And Transformations Of Dissolved Organic Matter In Large Arctic Rivers, Karl Kaiser, Maria Canedo-Oropeza, Rachel Mcmahon, Eainer M. W. Amon
Origins And Transformations Of Dissolved Organic Matter In Large Arctic Rivers, Karl Kaiser, Maria Canedo-Oropeza, Rachel Mcmahon, Eainer M. W. Amon
OES Faculty Publications
Arctic river watersheds are important components of the global climate system and show an amplified response to climate change. Here, we characterize origins and transformations of dissolved organic matter (DOM) in five major Arctic rivers (Kolyma, Lena, Yenisei, Ob, Mackenzie) over 3 years with seasonal sampling periods using measurements of carbohydrates, amino acids, bacterial biomarkers (D-amino acids), and plant protein biomarkers (hydroxyproline). A strong seasonal cycle of bioavailable DOM export was observed that correlated with discharge, vegetation, river morphology and water residence time. The chemical composition of bioavailable DOM was different among rivers reflecting unique characteristics of Arctic river watersheds. …
Reproductive Phase Determination In Male Meagre (Argyrosomus Regius, Sciaenidae): Testis Development And Histologic Corroboration Of A Gross Anatomical Scale, Nuno Prista, Leonel Gordo, Jose L. Costa, Maria J. Costa, Cynthia M. Jones
Reproductive Phase Determination In Male Meagre (Argyrosomus Regius, Sciaenidae): Testis Development And Histologic Corroboration Of A Gross Anatomical Scale, Nuno Prista, Leonel Gordo, Jose L. Costa, Maria J. Costa, Cynthia M. Jones
OES Faculty Publications
Reproductive stage determination of male gonads has received sparse attention in fish biology literature with few studies detailing the building of gross anatomical-and histologic scales. The meagre (Argyrosomus regius) is one of the world's largest sciaenids and supports a significant regional fishery in European and North African waters whose reproductive patterns are yet to be fully investigated. In the present study, we derive a macroscopic grading system for meagre testis using semi-quantitative graphs that feature the testis variability along the species size range and time of the year. We then describe the histological stages and reproductive phases of …
Emergence Of Algal Blooms: The Effects Of Short-Term Variability In Water Quality On Phytoplankton Abundance, Diversity, And Community Composition In A Tidal Estuary, Todd A. Egerton, Ryan E. Morse, Harold G. Marshall, Margaret R. Mulholland
Emergence Of Algal Blooms: The Effects Of Short-Term Variability In Water Quality On Phytoplankton Abundance, Diversity, And Community Composition In A Tidal Estuary, Todd A. Egerton, Ryan E. Morse, Harold G. Marshall, Margaret R. Mulholland
OES Faculty Publications
Algal blooms are dynamic phenomena, often attributed to environmental parameters that vary on short timescales (e.g., hours to days). Phytoplankton monitoring programs are largely designed to examine long-term trends and interannual variability. In order to better understand and evaluate the relationships between water quality variables and the genesis of algal blooms, daily samples were collected over a 34 day period in the eutrophic Lafayette River, a tidal tributary within Chesapeake Bay's estuarine complex, during spring 2006. During this period two distinct algal blooms occurred; the first was a cryptomonad bloom and this was followed by a bloom of the mixotrophic …
Fish Species Distribution In Seagrass Habitats Of Chesapeake Bay Are Structured By Abiotic And Biotic Factors, Jason J. Schaffler, Jacques Van Montfrans, Cynthia M. Jones, Robert J. Orth
Fish Species Distribution In Seagrass Habitats Of Chesapeake Bay Are Structured By Abiotic And Biotic Factors, Jason J. Schaffler, Jacques Van Montfrans, Cynthia M. Jones, Robert J. Orth
OES Faculty Publications
Seagrass habitats have long been known to serve as nursery habitats for juvenile fish by providing refuges from predation and areas of high forage abundance. However, comparatively less is known about other factors structuring fish communities that make extensive use of seagrass as nursery habitat. We examined both physical and biological factors that may structure the juvenile seagrass-associated fish communities across a synoptic-scale multiyear study in lower Chesapeake Bay. Across 3years of sampling, we collected 21,153 fish from 31 species. Silver Perch Bairdiella chrysoura made up over 86% of all individuals collected. Nine additional species made up at least 1% …
Δ13c Is A Signature Of Light Availability And Photosynthesis In Seagrass, Xingping Hu, David J. Burdige, Richard C. Zimmerman
Δ13c Is A Signature Of Light Availability And Photosynthesis In Seagrass, Xingping Hu, David J. Burdige, Richard C. Zimmerman
OES Faculty Publications
We explored the role of light-saturated (carbon-limited) photosynthesis on δ¹³C of turtlegrass (Thalassia testudinum Banks ex Konig) populations from the clear, blue waters of the Great Bahama Bank and the turbid, green waters of Florida Bay using field observations and radiative transfer models. Consistent with numerous previous observations, leaf δ¹³C decreased significantly with water depth in both regions. However the δ¹³C for Bahamas turtlegrass was 3 parts per thousand heavier than that for Florida Bay turtlegrass at equivalent depths, and broadband irradiance explained even less of the δ¹³C variations than depth. Instead, leaf δ¹³C showed a stronger relationship to …
Anaerobic Oxidation Of Methane And The Stoichiometry Of Remineralization Processes In Continental Margin Sediments, David J. Burdige, Tomoko Kamada
Anaerobic Oxidation Of Methane And The Stoichiometry Of Remineralization Processes In Continental Margin Sediments, David J. Burdige, Tomoko Kamada
OES Faculty Publications
In many coastal and continental margin sediments, pore-water property-property plots yield values of rc:s, the stoichiometric ratio of dissolved inorganic carbon (DIC) produced to sulfate reduced, that are lower than the commonly assumed value of 2. Remineralization of organic matter more reduced than CH2O can cause such observations, as can DIC loss due to authigenic carbonate precipitation. However, through studies of Santa Monica Basin sediments, we have observed that these observations could also be related to the occurrence of anaerobic oxidation of methane (AOM) in sediments. Specifically, using a reactive transport sediment model, we have shown …
The Use Of Extractable Lipofuscin For Age Determination Of Crustaceans: Reply To Sheehy (2008), H. Rodger Harvey, David H. Secor, Se-Jong Ju
The Use Of Extractable Lipofuscin For Age Determination Of Crustaceans: Reply To Sheehy (2008), H. Rodger Harvey, David H. Secor, Se-Jong Ju
OES Faculty Publications
The heterogeneous mixture of metabolic by-products termed lipofuscin (LF) or age pigments has long been known to accumulate in post mitotic cells with increasing age. In crustaceans several approaches have been developed over the years to track LF accumulation and provide a proxy for chronological age. Histological approaches have been traditionally used for LF determination of crustaceans (e.g. Sheehy et al. 1994, Mar Biol 121:237-245), but over the last decade extraction approaches for neural tissues have been introduced (Ju et al. 1999, Mar Ecol Prog Ser 185:171-179) and tested (Ju et al. 2001, Mar Ecol Prog Ser 224:197-205; 2003, Fish …
Marine And Freshwater Cyanophages In A Laurentian Great Lake: Evidence From Infectivity Assays And Molecular Analyses Of G20 Genes, Steven W. Wilhelm, Matthew J. Carberry, Melanie L. Eldridge, Leo Poorvin, Matthew A. Saxton, Martina A. Doblin
Marine And Freshwater Cyanophages In A Laurentian Great Lake: Evidence From Infectivity Assays And Molecular Analyses Of G20 Genes, Steven W. Wilhelm, Matthew J. Carberry, Melanie L. Eldridge, Leo Poorvin, Matthew A. Saxton, Martina A. Doblin
OES Faculty Publications
While it is well established that viruses play an important role in the structure of marine microbial food webs, few studies have directly addressed their role in large lake systems. As part of an ongoing study of the microbial ecology of Lake Erie, we have examined the distribution and diversity of viruses in this system. One surprising result has been the pervasive distribution of cyanophages that infect the marine cyanobacterial isolate Synechococcus sp. strain WH7803. Viruses that lytically infect this cyanobacterium were identified throughout the western basin of Lake Erie, as well as in locations within the central and eastern …
Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman
Dynamics Of Carbon Allocation In A Deep-Water Population Of The Deciduous Kelp Pleurophycus Gardeneri (Laminariales), Clare M. Dominik, Richard C. Zimmerman
OES Faculty Publications
Pleurophycus gardneri (Laminariales) is common in the low intertidal of the Northeast Pacific, but dominates many deep (30 to 40 m) rocky reefs in central California. Seasonal dynamics of productivity and resource allocation of a deep-water population of this deciduous, stipitate kelp were studied to understand how blade abscission affects the annual carbon budget. Patterns of growth, metabolism, and carbon storage and mobilization were measured monthly for 1 yr relative to in situ light and temperature, and used to model the annual carbon budget. The resulting carbon budget was used to determine if blade abscission effectively reduced respiratory demand during …
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
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 …
Interactive Regulation Of Dissolved Copper Toxicity By An Estuarine Microbial Community, Christina L. Dryden, Andrew S. Gordon, John R. Donat
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+, …
Hydrogeological Characterization Of The South Oyster Bacterial Transport Site Using Geophysical Data, Susan S. Hubbard, Jinsong Chen, John Peterson, Ernest L. Majer, Kenneth H. Williams, Donald J. Swift, Brian Mailloux, Yoram Rubin
Hydrogeological Characterization Of The South Oyster Bacterial Transport Site Using Geophysical Data, Susan S. Hubbard, Jinsong Chen, John Peterson, Ernest L. Majer, Kenneth H. Williams, Donald J. Swift, Brian Mailloux, Yoram Rubin
OES Faculty Publications
A multidisciplinary research team has conducted a field-scale bacterial transport study within an uncontaminated sandy Pleistocene aquifer near Oyster, Virginia. The overall goal of the project was to evaluate the importance of heterogeneities in controlling the field-scale transport of bacteria that are injected into the ground for remediation purposes. Geochemical, hydrological, geological, and geophysical data were collected to characterize the site prior to conducting chemical and bacterial injection experiments. In this paper we focus on results of a hydrogeological characterization effort using geophysical data collected across a range of spatial scales. The geophysical data employed include surface ground-penetrating radar, radar …
Top-Down Impact Through A Bottom-Up Mechanism. In Situ Effects Of Limpet Grazing On Growth, Light Requirements And Survival Of The Eelgrass Zostera Marina, Richard C. Zimmerman, Diana L. Steller, Donald G. Kohrs, Randall S. Alberte
Top-Down Impact Through A Bottom-Up Mechanism. In Situ Effects Of Limpet Grazing On Growth, Light Requirements And Survival Of The Eelgrass Zostera Marina, Richard C. Zimmerman, Diana L. Steller, Donald G. Kohrs, Randall S. Alberte
OES Faculty Publications
Temporal changes in abundance, size, productivity, resource allocation and light requirements of a subtidal eelgrass (Zostera marina L.) population were followed for 2 yr after the September 1993 appearance of a previously rare oval form of the commensal limpet Tectura depicta (Berry) in Monterey Bay, California, USA, By exclusively targeting the epidermis, limpet grazing impaired photosynthetic performance but left respiratory demand, meristematic growth and more than 90 % of the leaf biomass intact, The resulting low P:R ratios of grazed plants raised the light requirements for the maintenance of positive carbon balance almost 2-fold relative to healthy ungrazed plants …
Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett
Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett
OES Faculty Publications
We investigated the ability of trace element and isotopic signatures in otoliths to record the nursery areas of juvenile (young-of-the-year) weakfish Cynoscion regalis from the east coast of the USA. Juvenile C. regalis were captured with otter trawls at multiple sites in Doboy Sound (Georgia), Pamlico Sound (North Carolina), Chesapeake Bay (Virginia), Delaware Bay (Delaware) and Peconic Bay (New York), from July to September 1996. One sagittal otolith from each specimen was assayed for Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca ratios using inductively coupled plasma mass spectrometry (ICP-MS), while delta 13 C and delta 18 O values from the other sagittal …
Trace Element Signatures In Otoliths Record Natal River Of Juvenile American Shad (Alosa Sapidissima), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana, James W. Mclaren, Joseph W. H. Lam
Trace Element Signatures In Otoliths Record Natal River Of Juvenile American Shad (Alosa Sapidissima), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana, James W. Mclaren, Joseph W. H. Lam
OES Faculty Publications
The elemental composition of fish otoliths may represent a permanent record of the environmental conditions an individual has experienced as trace elements, incorporated into the growing surface of the otolith, reflect the physical and chemical characteristics of the ambient water. We tested the utility of trace element signatures in otoliths as natural tags of the river of origin of juvenile American shad (Alosa sapidissima) collected from the Connecticut, Hudson and Delaware Rivers in August and October 1994. Four elements (K, Mn, Sr, and Ba) showed significant variability among sites within rivers in August, although only Mg showed a …
Response Of Otolith Microchemistry To Environmental Variations Experienced By Larval And Juvenile Atlantic Croaker (Micropogonias Undulatus), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana
Response Of Otolith Microchemistry To Environmental Variations Experienced By Larval And Juvenile Atlantic Croaker (Micropogonias Undulatus), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana
OES Faculty Publications
Minor and trace elements incorporated into otoliths during growth may permanently record environmental conditions experienced by fishes. To determine the validity of this approach, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to assay sectioned otoliths from juvenile Atlantic croaker (Micropogonias undulatus) collected from each of three sites in the Neuse River, North Carolina, and the Elizabeth River, Virginia. Elemental concentrations at the center of the otoliths did not differ between locations, although both Mg : Ca and Ba : Ca were significantly higher at the edge of otoliths from the Neuse River than from the …
A Reproductive-Resting Stage In An Harpacticoid Copepod, And The Significance Of Genetically Based Differences Among Populations, D. J. Lonsdale, P. Weissman, Fred C. Dobbs
A Reproductive-Resting Stage In An Harpacticoid Copepod, And The Significance Of Genetically Based Differences Among Populations, D. J. Lonsdale, P. Weissman, Fred C. Dobbs
OES Faculty Publications
Dormancy is an important life-history strategy which allows copepods to increase their fitness by delaying growth and reproduction until harsh environmental conditions have ameliorated. For marine species, the primary strategies identified to date include the production of dormant eggs by shallow-water species, and copepodite overwintering in deep-water species. Herein, we describe a third strategy in which fertilized adult females enter a “reproductive-resting” stage during the late fall that allows them to overwinter and provide a first source of spring naupliar recruitment. This strategy has been observed in the estuarine copepod Coullana canadensis, but may also occur in other species. …
Is Growth Of Eelgrass Nitrogen Limited? A Numerical Simulation Of The Effects Of Light And Nitrogen On The Growth Dynamics Of Zostera Marina, Richard C. Zimmerman, Robert D. Smith, Randall S. Alberte
Is Growth Of Eelgrass Nitrogen Limited? A Numerical Simulation Of The Effects Of Light And Nitrogen On The Growth Dynamics Of Zostera Marina, Richard C. Zimmerman, Robert D. Smith, Randall S. Alberte
OES Faculty Publications
A numerical model of nitrogen uptake and growth was developed for the temperate seagrass Zostera marina L. Goals were to evaluate the relative effects of light and nitrogen availability on nitrogen uptake and partitioning between leaf and root tissue, and to estimate nitrogen concentrations in the sedment and water column required to saturate growth. Steady-state predictions are quite robust with respect to a range of parameter values justified by available data The calculations indicated that roots are probably more important in overall nitrogen acquisition in most light and nitrogen environments encountered in situ, but may contribute less than 50 …
Sediment Processing And Selective Feeding By Pectinaria Koreni (Polychaeta: Pectinariidae), Fred C. Dobbs, Teresa A. Scholly
Sediment Processing And Selective Feeding By Pectinaria Koreni (Polychaeta: Pectinariidae), Fred C. Dobbs, Teresa A. Scholly
OES Faculty Publications
Pectinaria (Lagis) koreni (Malmgren) is an abundant, deposit-feeding, infaunal inhabitant of shallow-water marine environments in northern Europe. Laboratory experiments were performed to quantify the polychaete's sediment processing in 2 distinct sediments, 1 fine-grained and high in combustibles, the other coarse-grained and low in combustibles. Gut passage time and time to pseudodefecation were predictable only in coarse-grained sediment. In both sediments, reworking rate increased with worm size and over time, although temporal patterns differed in the 2 sediments. The ratio of pseudodefecated sediment to defecated sediment did not differ significantly over time in either sediment, but the ratio was greater in …
Monitoring Defecation Activity Of Infaunal Deposit Feeders, Fred C. Dobbs
Monitoring Defecation Activity Of Infaunal Deposit Feeders, Fred C. Dobbs
OES Faculty Publications
An inexpensive, reliable thermistor device capable of monitoring infaunal foraging activity was built and used in the laboratory to examine effects of temperature on sediment reworking by the maldanld polychaete Clymenella torquata. The worm defecated at least once per hour 55.0 % (12.0 "C) to 88.2 % (5.5 "C) of the time. Defecation rate was linearly and positively related to temperature. Estimated volume of sediment ejected per defecation (0.015 ml) did not change with temperature. Results are compared with previous reworking studies of C. torquata.