DIALNET OAI Articles
Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.
Mostrando recursos 1 - 20 de 19.324
Nutrient limitation of phytoplankton growth and physiology in a subtropical estuary (Pensacola Bay, Florida) - Juhl, Andrew R.; Murrell, Michael C.
Phytoplankton nutrient limitation was studied in a sub-estuary of lower Pensacola Bay using multiple techniques in parallel. Nutrient-addition bioassays indicated year-round nutrient limitation, in contrast to seasonal patterns often described for higher-latitude estuaries. Although an earlier study found frequent P-limitation in Pensacola Bay, N-limitation dominated during this study, despite dissolved inorganic N:P ratios consistently above Redfield proportions. However, combined N and P additions enhanced phytoplankton growth more than single nutrients, indicating incipient co-limitation. In-situ alkaline phosphatase (Pase) activity was not clearly related to inorganic nutrient concentrations or ratios. however, changes in Pase activity after nutrient additions were consistent with the...
Short-term dispersal of an intentionally-released patch of larval Mercenaria Spp. in the Indian River Lagoon, Florida, USA - Hitchcock, Gary L.; Arnold, William S.; Frischer, Marc; Kelble, Christopher; Cowen, Robert K.
In July 1998 approximately 2.5 × 108 of recently-spawned Mercenaria spp. larvae were intentionally released in the northernmost basin of the Indian River Lagoon, Florida, to characterize the initial dispersion from a point source at time scales of hours to days. Larval densities measured with a quantitative molecular method indicated ambient concentrations were enhanced by 10 larvae L-1 near surface drifters released with the larvae. Surface distributions from samples collected near the drifters indicate that larval patches developed during the first day. diffusive processes evaluated from dye releases yield apparent diffusivity coefficients that suggest diffusive processes could spread larvae over...
Description of a new northeastern Atlantic aeolid of the genus Flabellina (Mollusca, Nudibranchia) - González-Duarte, Manuel M.; Cervera Currado, Juan Lucas; Poddubetskaia, Marina
A new species of aeolid nudibranch of the genus Flabellina Voigt, 1834 is described from the Bay of Arcachon (France), in the northeastern Atlantic. This species is cryptic of the aeolid Piseinotecus gaditanus Cervera, García and García, 1987. The external appearance is identical to P. gaditanus: body color is translucent white, ceratal surface transparent, digestive gland duct bright red and apex translucent white. The cerata arise from peduncles arranged in groups of five to seven, and opaque white spots are scattered all over the cerata surface. The radula is triseriate and the rachidian tooth has a triangular central cusp. The...
Genetic divergence among sympatric populations of three species of oyster drills (Urosalpinx) in Cedar Key, Florida - Robinson, John D.; Dillon, Robert T.
Three gastropod species of the genus Urosalpinx inhabit intertidal and subtidal regions of the southeastern United States. Urosalpinx cinerea (Say, 1822) is native to the Atlantic coast from Newfoundland to northeast Florida, while Urosalpinx perrugata (Conrad, 1846) and Urosalpinx tampaensis (Conrad, 1846) are largely restricted to the Gulf of Mexico. The morphological similarity of U. cinerea and U. perrugata is so striking that they have been suggested to be subspecies. We used a combination of molecular and morphological methods to examine divergence among populations of these three nominal species in a newly discovered area of sympatry: Cedar Key, Florida. Significant...
Primera cita de Mauremys leprosa (Sauropsida: Testudines) a Sant Mateu del Maestrat - Vallès, V. Francesca; Escobar, J. Vicente; Forner Valls, Enric
La tortuga de rierol, Mauremys leprosa (Scheigger, 1812), és citada per primer cop a Sant Mateu del Maestrat (el Baix Maestrat). Es fa una primera valoració de l'estat de la població, que es considera bona, amb una estructura d'edat normal i amb abundants exemplars juvenils que asseguren el reemplaçament. No s'han observat altres tortugues d'aigua a la zona.
Sobre la presencia del bonetero de hoja ancha (Celastraceae) en la Comunidad Valenciana - Fabregat Llueca, Carlos; Casabo, Joan; Aguilella Palasí, Antoni
This paper deals with the occurrence of the Broad-leaved Spindle Euonymus latifolius (L.) Miller in two localities of the Valencian Community (E Spain). In one of these localities (Alpuente, Valencia) the plant is believed to be extinct, while the second one (El Toro, Castellón) would be the only confirmed location in the Valencian Community.
Sobre Vidaliella gerundensis (Vidal, 1883) del Paleogen de Vallibona (els Ports) - Gual Orti, Vicent; Forner Valls, Enric
Es confirma l'existència de Paleogen a Vallibona (els Ports, nord-est de la Península Ibèrica), tot i que no està cartografiat per l'IGME. S'estudia la població de l?espècie Vidaliella gerundensis (Vidal, 1883). Els nivells amb fòssils continentals lacustres s'assignen al final del Paleocè, al Thanetià. Es cita un nou jaciment de Paleogen continental no conegut: mas de Telers (Vallibona, els Ports). S'amplia la fauna citada amb un nou gasteròpode.
Migración e invernada diferencial del mosquitero común (Phylloscopus collybita) en una zona húmeda del levante ibérico - Castany Àlvaro, Joan; Tirado Bernat, Miguel
We studied the behavior of the chiffchaff (Phylloscopus collybita) outside the breeding season in Paraje Natural del Prat de Cabanes-Torreblanca. We observed two different migration periods separated by a central one. In the post breeding season we observed two different waves, in the first one, females were more abundant than males, and the speed of passage was faster, while in the second, male proportion increased greatly and the speed of passage decreased. The post breeding median date of the females was 3 days before males. In the pre breed- ing migration we observed a passing pattern: adult male - young...
Biomonitorización Humana de contaminantes ambientales - Roca Marugán, Marta Isabel; Yusá Pelechá, Vicent
Abstract: Human Biomonitoring (HBM) is a useful tool for health protection against exposure to chemicals through a systematic analysis of pollutants and/or its metabolites in biological samples. Many governments are working to integrate biomonitoring programs in environmental monitoring plans of pollutants in food, water and air, providing a more accurate exposure assessment and risk characterization in populations derived from environmental pollution.
Primera addenda al catàleg de fòssils castellonencs - Forner Valls, Enric; Gual Orti, Vicent
S'amplia el catàleg dels fòssils castellonencs amb 25 espècies. Es publica la llista completa amb tota la bibliografia de les descripcions respectives. Es completa amb informació addicional dels autors, figures, situació dels holotips i diversos aspectes de la descripció.
Sexual reproduction in the invasive octocoral Carijoa Riisei in Hawaii - Kahng, Samuel E.; Benayahu, Yehuda; Wagner, Daniel; Rothe, Nina
Since its initial discovery on Oahu in 1966, the azooxanthellate octocoral, Carijoa riisei (Duchassaing and Michelotti, 1860), has spread across the main Hawaiian Islands and proliferated in abundance. To help understand the substantial ecological success of C. riisei in Hawaii, its sexual reproduction was examined. Carijoa riisei is gonochoric with a male to female ratio of one. Gametogenesis is asynchronous, continuous, and does not exhibit seasonal or lunar periodicity. Carijoa riisei spawns negatively buoyant eggs which suggests external fertilization and possibly benthic larvae. Under favorable conditions, C. riisei exhibits high polyp fecundity. Asynchronous, continuous spawning of gametes is an unusual...
Covering Behavior of Two Co-occurring Jamaican Sea Urchins: Differences in the Amount of Covering and Selection of Covering Material - Sullan, Kathryn M.; Wright, Paul R.; Amato, Katherine R.; Emel, Sarah L.; Lindgren, Catrina A.
In Discovery Bay, Jamaica, Tripneustes ventricosus (Lamarck, 1816) and Lytechinus variegatus (Lamarck, 1816) co-occur on shallow substrata with varying proportions of turtle grass (Thalassia testudinum Banks and Soland. ex Koenig) and coral rubble. Both cover their aboral surface with grass fragments and small pieces of rubble or shell. We tested the hypothesis that these species differ in covering behavior and actively select different covering material. Field observations in three habitats with different proportions of grass cover (< 30% grass, 50% grass, and > 70% grass) showed that L. variegatus covered significantly more of its surface than T. ventricosus in all...
Production of Dissolved and Particulate Organic Matter by the Reef-building Corals Porites cylindrica and Acropora pulchra - Tanaka, Yasuaki; Miyajima, Toshihiro; Koike, Isao; Hayashibara, Takeshi; Ogawa, Hiroshi
Coral colonies are one of the major producers of dissolved and particulate organic matter (DOM and POM, respectively) in coral reefs. To investigate the net release rates of DOM and POM and the production ratios (DOM:POM), the reef-building corals Porites cylindrica (Dana, 1846) and Acropora pulchra (Brook, 1891) were incubated separately and accumulation rates of DOM and POM in the overlaying seawater were simultaneously measured over 4 d. Release rates of the newly synthesized organic matter by symbiotic algal photosynthesis were also measured using a 13C-labeling technique. Dissolved organic carbon (DOC) was produced at rates of 340 and 380 nmol...
Abundance, Spatial Distribution, and Size Structure of the Sea Star Protoreaster nodosus in Palau, with Notes on Feeding and Reproduction - Scheibling, Robert E.; Metaxas, Anna
Protoreaster nodosus (Linnaeus, 1758) is a common sea star in shallow sand and seagrass habitats in the tropical Indo-pacific region. It has been extensively harvested as an ornament, but little is known of its biology and ecology. We quantitatively sampled populations at five sites in palau to obtain baseline information on abundance, spatial distribution, and population structure of this species in areas unaffected by human depredation. Density on sand bottoms ranged from 4 to 32 individuals 100 m-2 and biomass from 3.1 to 20.7 kg 100 m-2. Population size estimates at two locations were 100 and 630 individuals. Mean size...