Letteratura scientifica selezionata sul tema "Marine invertebrates – Reproduction"
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Articoli di riviste sul tema "Marine invertebrates – Reproduction"
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Tyler, P. A. "Reproduction of marine invertebrates, Volume VI". Journal of Experimental Marine Biology and Ecology 162, n. 1 (ottobre 1992): 140–41. http://dx.doi.org/10.1016/0022-0981(92)90130-3.
Testo completo
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Langston, W. J. "Endocrine disruption and altered sexual development in aquatic organisms: an invertebrate perspective". Journal of the Marine Biological Association of the United Kingdom 100, n. 4 (giugno 2020): 495–515. http://dx.doi.org/10.1017/s0025315420000533.
Testo completoAbstract (sommario):
AbstractContaminants causing sex-altering, endocrine disrupting-like (ED) effects, or otherwise influencing reproduction, have been of growing concern to humans for more than 50 years. They have also been a perturbing, though less well-studied, phenomenon in marine organisms, following the recognition of tributyltin (TBT)-induced imposex and population extinctions in (neo)gastropods in the 1970s. Whilst ED impacts in mammals and fish are characterized by mimicry or antagonism of endogenous hormones by environmental contaminants (acting through Nuclear Receptors which are present in all metazoans) much less is known regarding pathways to effects in invertebrates. Despite the absence of a defined steroidal/mechanistic component, the extent, severity and widespread nature of ED-like manifestations and altered sexual characteristics observed in marine invertebrates gives rise to comparable concerns, and have been a long-term component of the MBA's research remit. The manifestations seen in sensitive taxa such as molluscs and crustaceans confirm they are valuable indicators of environmental quality, and should be exploited in this capacity whilst we seek to understand the pervasiveness and underlying mechanisms. In so doing, invertebrate indicators address aims of organizations, such as the EEA, OECD, UNEP and WHO, charged with management and monitoring of chemicals and ensuring that adverse effects on humans and the environment are minimized (Bergman et al., 2013). In view of the recent general declines in marine biodiversity, and the potential contribution of ED-like phenomena, safeguarding against deleterious effects through increased research which links pollutant exposure with reproductive dysfunction among invertebrates, is seen as a high priority.
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PEARSE, JOHN S., JAMES B. MCCLINTOCK e ISIDRO BOSCH. "Reproduction of Antarctic Benthic Marine Invertebrates: Tempos, Modes, and Timing". American Zoologist 31, n. 1 (febbraio 1991): 65–80. http://dx.doi.org/10.1093/icb/31.1.65.
Testo completo
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Young, Craig M. "Invertebrate Reproduction and Development Reproduction and Development of Marine Invertebrates W. Herbert Wilson, Jr. Stephen A. Stricker George L. Shinn". BioScience 46, n. 6 (giugno 1996): 460–61. http://dx.doi.org/10.2307/1312883.
Testo completo
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TYLER, P. A., e C. M. YOUNG. "Reproduction in marine invertebrates in “stable” environments: the deep sea model". Invertebrate Reproduction & Development 22, n. 1-3 (dicembre 1992): 185–92. http://dx.doi.org/10.1080/07924259.1992.9672271.
Testo completo
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Serkedjieva, Julia, Monika Konaklieva, Stefka Dimitrova-Konaklieva, Veneta Ivanova, Kamen Stefanov e Simeon Popov. "Antiinfluenza Virus Effect of Extracts from Marine Algae and Invertebrates". Zeitschrift für Naturforschung C 55, n. 1-2 (1 febbraio 2000): 87–93. http://dx.doi.org/10.1515/znc-2000-1-217.
Testo completoAbstract (sommario):
Abstract Sixty products, derived from marine organisms, typical of the Bulgarian Black Sea coast, were examined for inhibitory activity on the reproduction of influenza viruses in tissue cultures. The antiviral effect was investigated by the reduction of virus infectivity. Using representative strains of influenza virus it was shown that apparently the inhibitory effect was strain-specific. The most effective products were further studied in fertile hen’s eggs and in experimental influenza infection in white mice.
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Pechenik, Jan A., Morgan Levy e Jonathan D. Allen. "Instant OceanVersusNatural Seawater: Impacts on Aspects of Reproduction and Development in Three Marine Invertebrates". Biological Bulletin 237, n. 1 (agosto 2019): 16–25. http://dx.doi.org/10.1086/705134.
Testo completo
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Di Costanzo, Federica, Valeria Di Dato, Adrianna Ianora e Giovanna Romano. "Prostaglandins in Marine Organisms: A Review". Marine Drugs 17, n. 7 (23 luglio 2019): 428. http://dx.doi.org/10.3390/md17070428.
Testo completoAbstract (sommario):
Prostaglandins (PGs) are lipid mediators belonging to the eicosanoid family. PGs were first discovered in mammals where they are key players in a great variety of physiological and pathological processes, for instance muscle and blood vessel tone regulation, inflammation, signaling, hemostasis, reproduction, and sleep-wake regulation. These molecules have successively been discovered in lower organisms, including marine invertebrates in which they play similar roles to those in mammals, being involved in the control of oogenesis and spermatogenesis, ion transport, and defense. Prostaglandins have also been found in some marine macroalgae of the genera Gracilaria and Laminaria and very recently the PGs pathway has been identified for the first time in some species of marine microalgae. In this review we report on the occurrence of prostaglandins in the marine environment and discuss the anti-inflammatory role of these molecules.
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Kinoshita-Terauchi, Nana, Kogiku Shiba, Makoto Terauchi, Francisco Romero, Héctor Vincente Ramírez-Gómez, Manabu Yoshida, Taizo Motomura, Hiroshi Kawai e Takuya Nishigaki. "High potassium seawater inhibits ascidian sperm chemotaxis, but does not affect the male gamete chemotaxis of a brown alga". Zygote 27, n. 4 (18 luglio 2019): 225–31. http://dx.doi.org/10.1017/s0967199419000224.
Testo completoAbstract (sommario):
SummaryMale gamete chemotaxis towards the female gamete is a general strategy to facilitate the sexual reproduction in many marine eukaryotes. Biochemical studies of chemoattractants for male gametes of brown algae have advanced in the 1970s and 1980s, but the molecular mechanism of male gamete responses to the attractants remains elusive. In sea urchin, a K+ channel called the tetraKCNG channel plays a fundamental role in sperm chemotaxis and inhibition of K+ efflux through this channel by high K+ seawater blocks almost all cell responses to the chemoattractant. This signalling mechanism could be conserved in marine invertebrates as tetraKCNG channels are conserved in the marine invertebrates that exhibit sperm chemotaxis. We confirmed that high K+ seawater also inhibited sperm chemotaxis in ascidian, Ciona intestinalis (robusta), in this study. Conversely, the male gamete chemotaxis towards the female gamete of a brown alga, Mutimo cylindricus, was preserved even in high K+ seawater. This result indicates that none of the K+ channels is essential for male gamete chemotaxis in the brown alga, suggesting that the signalling mechanism for chemotaxis in this brown alga is quite different from that of marine invertebrates. Correlated to this result, we revealed that the channels previously proposed as homologues of tetraKCNG in brown algae have a distinct domain composition from that of the tetraKCNG. Namely, one of them possesses two repeats of the six transmembrane segments (diKCNG) instead of four. The structural analysis suggests that diKCNG is a cyclic nucleotide-modulated and/or voltage-gated K+ channel.
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OLIVE, P. J. W. "The adaptive significance of seasonal reproduction in marine invertebrates: the importance of distinguishing between models". Invertebrate Reproduction & Development 22, n. 1-3 (dicembre 1992): 165–74. http://dx.doi.org/10.1080/07924259.1992.9672269.
Testo completoTesi sul tema "Marine invertebrates – Reproduction"
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Ndhlovu, Rachel Tintswalo. "Temporal variability in the fatty acid composition of suspension-feeders and grazers on a South African rocky shore". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1020879.
Testo completoAbstract (sommario):
Numerous ecological studies have used lipids to determine trophic pathways in aquatic systems, as fatty acid profiles provide time-integrated information on an organism’s assimilated diet. Many of these studies have, however, been based on sample collections with a limited temporal scale. The trophic ecology of pelagic systems has been studied intensively using fatty acid analyses, but very little work has been directed toward benthic communities, with the intertidal being especially neglected. The investigation of trophic pathways within rocky shore communities will help us to better understand system responses to environmental changes. The determination of long term temporal variation of the food web within a community could reveal the type, magnitude, duration and frequency of highly seasonal productivity. Changes in fatty acid profiles through time in primary consumers of intertidal rocky shores are poorly understood, but represent an important step towards a more comprehensive understanding of rocky shore food webs, compared with those derived from snapshot or short-term studies. The aim of this thesis was to clarify the temporal variability in the diets of rocky shore intertidal suspension-feeders (the brown mussels Perna perna and the Cape reef worm, Gunnarea gaimardi) and grazers (the Cape sea urchin Parencinus angulosus and the Goat-eye limpet, Cymbulus oculus) on the south east coast of South Africa using fatty acid profiles, and to investigate the effects of life style (e.g. feeding mode) and life cycle on temporal variations in tissue fatty acid profiles. I had three hypotheses: firstly, that suspension-feeders experience high levels of variability in their diets through time because water quality has the potential to change quickly and drastically, whereas grazers experience less variability in their diets over time since their food sources are more constant. Secondly, the reproductive cycles of the suspension-feeder P. perna and the grazer P. angulosus affect the fatty acid composition of their gonads, with temporal variations in lipid composition reflecting changes in reproduction investment. Thirdly, the total amount of energetic reserves available for reproduction are different for each gender (females allocate more energy to egg production than males allocate to gamete production). To address these aims, fatty acid profiles of suspension-feeders and grazers were investigated over a period of twelve months (from July 2010 to June 2011) at a single site on the south east coast of South Africa. The results showed high variability in the fatty acid composition of both the suspension-feeders strongly related with changes in their food source (suspended particulate material). Furthermore, similar temporal changes in fatty acid profiles of the two suspension-feeders were observed over time, reflecting their common diet and life style. There were some inter-specific differences in the suspension-feeders, likely originating from differences in their particle capturing mechanisms. Grazers showed less variability through time compared with the suspension-feeders, with the limpets being more consistent than the sea urchins. The temporal variability in the sea urchin diets may have resulted from the highly diverse and heterogeneous food sources available to them, whereas limpets may be more selective and have a limited range of diet items. Differences between the two grazer species may have arose from differences in their feeding strategies and intertidal zonation. The fatty acid compositions of gonad tissues in both P. perna and P. angulosus showed temporal variability strongly related to reproductive cycle. Differences in the fatty acid values between females and males were apparent, with females richer in total and polyunsaturated fatty acids than males. Spawning and gametogenesis influenced the variability of fatty acids through time in both species, suggesting the importance of considering the reproductive cycle when studying lipids in rocky shore species. Little evidence of lipid transfer between muscles and gonads was seen, suggesting the importance of direct lipid storage into the reproductive tissues. The influence of diet and life history of intertidal consumers on the temporal variability of their fatty acid compositions is important to understand, as it provides us with a better understanding of the functioning of rocky shore systems. There is an enormous potential for future research in this field of study.
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Canepa, Oneto Antonio Jesús. "Jellyfish of the Spanish Mediterranean coast: effects of environmental factors on their spatio-temporal dynamics and economic impacts". Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/284343.
Testo completoAbstract (sommario):
During recent years, jellyfish blooms have become in a passionate issue among marine scientists with a series of studies and reviews. The main concern about this blooms are related with ecosystem and socio-economic impacts and lately with the possibility of a global increase in these blooms. Jellyfish populations are known to follow periodic fluctuations in occurrence, abundance (biomass), where some regions, like the Mediterranean Sea, appear to sustain a long-term increase. The Mediterranean Sea has been largely and historically affected with blooms of several jellyfish species. Among them Pelagia noctiluca is the most abundant and the most problematic jellyfish species in the Western Mediterranean. Nevertheless, little information about the environmental restriction on the spatio-temporal dynamics of jellyfish blooms is available. In order to address these needs, this thesis has been structured covering two geographical areas reflecting two different approaches to understanding jellyfish spatio-temporal dynamics, bloom formation, impacts and analytical procedures. The first part of the thesis (Papers 1-3) deals with the outbreaks of the cubozoan Carybdea marsupialis along the coast of Denia (Alicante), including innovative work to develop experimentally based tools and analyses to generate scientifically-based recommendations for stakeholders. The second part of this thesis was done on the northern Mediterranean Spanish coast (Catalan coast) (Papers 4-6). This work is mostly based on stranded jellyfish data collected by the MEDUSA project in association with the Catalan Water Agency (ACA). The general objective of the Thesis was to understand the spatio-temporal dynamics of the jellyfish along the Spanish Mediterranean coast and the economic impacts of their blooms. Along the coast of Denia (Alicante), the coastal box jellyfish Carybdea marsupialis has caused major concern due to its painful sting and high abundances since 2008.The effects of environmental variables on the local (~ tens of kilometres) abundance of the cubomedusae showed that sea surface temperature (SST) and salinity were the main environmental variables, followed by those related to primary and secondary production and local retention or transportation to the coast. This conclusion led to our management recommendation that, to reduce the blooms of C. marsupialis, crop fertilizers and sewage discharges should be reduced in highly populated or industrialized areas. Most importantly, high amounts of nutrients reaching the coast (by rivers or ground water discharges) should be prevented, especially in early spring. The mauve stinger Pelagia noctiluca is the most common jellyfish in the Mediterranean Sea. Along the Catalan Coast, stranded P. noctiluca medusae occurred throughout the sampling period, but with highest abundances in spring and spatially correlated with submarine canyons. Bayesian analysis of the importance of stochastic versus deterministic drivers of jellyfish outbreaks along the Catalan Coast showed that jellyfish outbreaks were more frequent in May and June, particularly in the years 2009 and 2010. Results indicated that deterministic processes were more important than the stochastic component of environmental variation, suggesting that extreme events, visualized as the compound effects of environmental variables, did not affect the probability of an outbreak along the Catalan Coast. From a stated-choice questionnaire we calculated that the well-being gains associated with a reduction of jellyfish outbreaks in this area would range between €312 and €322 million annually, corresponding approximately to 19% of the tourism expenditures of the Catalan population in 2012. Improvement in the beach water quality was, by far, the most valuable attribute for all types of respondents. Improvement in the beach infrastructure was ranked second and reduction in the risk of jellyfish outbreaks, third. This study confirms the urgency to provide daily information by use of the wide set of social media applications.Los impactos de las proliferaciones masivas (blooms) de medusas sobre las actividades humanas, han aumentado en el último tiempo. Uno de los ecosistemas más afectados es el Mar Mediterráneo donde en las últimas décadas la frecuencia de los blooms, así como el número de especies involucradas han aumentado. Así, la necesidad de entender la dinámica espacio temporal de los blooms de medusas a lo largo de la costa Mediterránea española y sus impactos económicos, es de primera importancia. La primera parte de la tesis se desarrolló en la zona central (costa de Alicante), donde el bloom del cubozoo Carybdea marsupialis en 2008 afectó negativamente hasta 185 personas diarias, impactando negativamente al turismo local. La asociación positiva de esta especie con bajos niveles de salinidad y altos niveles de producción primaria permite sugerir que efectos sinérgicos de las descargas fluviales ricas en nutrientes por actividades agropecuarias, asociado a la transformación y alteración de hábitat, han favorecido a esta especie. La segunda parte se desarrolló en la zona norte (costa de Cataluña), donde un programa de monitoreo basado en ciencia ciudadana, reveló que siete especies de medusas son las más comunes en esta zona con diferentes dinámicas espacio – temporales. La especie más importante es el escifozoo Pelagia noctiluca, que mostró las máximas abundancias durante primavera. Altas abundancias de esta especie estuvieron espacialmente asociadas a la presencia de cañones submarinos, permitiendo establecer una nueva hipótesis acerca de la migración vertical estacional en esta especie. Los análisis bayesianos mostraron que las proliferaciones de medusas fueron más frecuentes en Mayo y Junio, particularmente en los años 2009 y 2010 en la costa Catalana. Los resultados mostraron también que los componentes determinísticos fueron más importantes que los componentes aleatorios de la variabilidad ambiental, sugiriendo que los eventos extremos no afectaron la probabilidad de una proliferación de medusas en estas costas. Basado en un cuestionario realizado a usuarios de la playa, se calculó que los bienes y servicios asociados a la reducción en proliferaciones masivas de medusas en la zona de la Costa Catalana estuvo entre €312 and €322 millones anuales, correspondiendo aproximadamente al 19% de los gastos en turismo en 2012. El mejoramiento en la calidad del agua fue el atributo más valorado, seguido por un mejoramiento en la infraestructura en las playas y la reducción en el riego de proliferaciones de medusas como el tercer atributo más valorado.
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Blanco, Sánchez Marta. "Historia de vida temprana e inversión reproductiva de invertebrados bentónicos: integración al manejo y conservación a través de modelos de dispersión = Early life and reproductive investment of benthic invertebrates: integration to management and conservation throught dispersal models". Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/666608.
Testo completoAbstract (sommario):
Las zonas costeras son uno de los ecosistemas que sufre mayor impacto antrópico a nivel mundial. La sobreexplotación de los recursos marinos es una de las actividades humanas que genera mayor impacto, reduciendo la abundancia y tamaño de las especies objetivo. Una de las medidas para proteger estos ecosistemas consiste en el establecimiento de áreas marinas protegidas. En Chile, el sistema actual de manejo de las pesquerías artesanales de especies bentónicas está basado en áreas parcialmente protegidas, las Áreas de Manejo y Explotación de Recursos Bentónicos (AMERBs), lo que ha supuesto una mejora en la sostenibilidad de una actividad de larga tradición en el país. Estas áreas entregan derechos de usos territoriales, conocidos mundialmente como TURF (sigla en inglés de Territorial Use Right for Fisheries). Sin embargo, actualmente estas áreas se gestionan de forma individualizada, de tal manera que la escala espacial de manejo no está acoplada a la escala de la dinámica de las poblaciones de invertebrados bentónicos. El objetivo de esta tesis es identificar áreas de alto valor para la producción, exportación y llegada de larvas en base a los patrones de historia de vida temprana, considerando variables y/o condicionantes relevantes de la fase adulta bentónica, como (a) la inversión reproductiva, (b) la densidad y talla de los adultos reproductores, variables determinantes de la distribución espacial de la producción de huevos y larvas, así como también variables que intervienen en la fase larval planctónica, como (c) los rasgos biológicos larvales, para acoplarlo con los patrones de circulación costera con el fin de contribuir a un mejor entendimiento de la dispersión y conectividad larval. Para este fin se seleccionaron dos especies relevantes social, comercial y ecológicamente: el erizo rojo (Loxechinus albus) y la lapa (Fissurella latimarginata). En primer lugar, se evaluó mediante muestreos de campo el efecto de la protección (relacionada con el régimen de explotación) y afloramiento costero sobre la inversión reproductiva y la condición individual de los adultos reproductores. Esta información sumada a los datos empíricos de distribución de tallas, densidad de individuos y fecundidad de las hembras reproductoras se utilizó para desarrollar un modelo de producción potencial de huevos en la costa central de Chile. Para el estudio del reclutamiento y dispersión se desarrolló un modelo biofísico de dispersión larvaria que permite evaluar el efecto de la variabilidad oceanográfica y los rasgos biológicos (migración vertical de las larvas y desarrollo dependiente de la temperatura) en la distancia de dispersión, el éxito del reclutamiento, y los patrones de conectividad larval. Los resultados sugieren que, para ambas especies, la protección y el afloramiento costero no tienen un efecto sobre la inversión reproductiva y la condición de los individuos. Sin embargo, la protección sí tuvo un efecto sobre la talla y densidad de individuos generando claros patrones espaciales de producción de gametos. Se observó que la variación geográfica y temporal de los procesos de circulación dominaneltransportey la dispersióndelas larvas enlaregión, independientemente de los rasgos biológicos evaluados. La mayoría del reclutamiento fue alóctono, con niveles bajos de auto-reclutamiento y retención local, incluso para la especie con un tiempo de vida planctónica corto (F. latimarginata). Los patrones geográficos de salida y llegada fueron similares para ambas especies, observándose una mayor importancia relativa de la región norte del dominio de estudio. Estos resultados permiten identificar los principales determinantes de la producción de huevos, el éxito del reclutamiento y la distancia de dispersión para dos especies de gran interés comercial en Chile, información que podría guiar recomendaciones para el manejo y la conservación en una de las regiones costeras más productivas pero también más explotadas del mundo.Coastal zones are one of the ecosystems receiving higher anthropic impact. Fishing is a major source of human impact, reducing density and size of exploited species. Marine protected areas are one of the strategies established to control fishing impacts. The current artisanal fisheries management system in Chile is based on partially protected areas, TURFs (Territorial Use Right for Fisheries). This system enhances sustainability of one of the traditional activity in the country. However, these areas are individually managed so the scale of resource management is not coupled with the scale of exploited population dynamics. The objective of this thesis dissertation is to identify areas of high value for propagule production as well as source and sink areas based on early life history patterns, considering variables relevant for the adult phase such as (a) reproductive output, (b) density and size of reproductive adults as both variables define the spatial distribution of eggs and larvae, as well as variables that affect the larval phase such as (c) larval biological traits, coupling these pieces of information with coastal circulation models to reach a better understanding of dispersal and larval connectivity. Two benthic invertebrates species exploited by artisanal fisheries in Chile, the red sea urchin (Loxechinus albus) and keyhole limpet (Fissurella latimarginata) were used as models. First, I evaluated the effect of protection and coastal upwelling on reproductive output and individual condition of reproductive adults. Based on size distribution, density of individuals and fecundity data I developed an egg production model along the central coast of Chile. Finally, I developed a biophysical larval dispersal model to assess the effect of oceanographic variability and larval biological traits (larval diel vertical migration and temperature-dependent larval development) on dispersal distance, recruitment success and connectivity patterns. These results showed that fishing regime and coastal upwelling did not affect individual reproductive output either individual condition for both species. However, fishing regime had an effect on size and density of individuals. I found that the geographic and temporal variation in circulation processes dominate transport and effective dispersal of larvae in the study region, regardless of larval biological traits. Most recruitment to local population was allochthonous, with low levels of self-recruitment and local retention even for the species with short planktonic larval duration. Similar geographic patterns of source and destination strengths were observed in both species, with the northern region of the studied domain showing relatively higher importance. These findings allow identifying primary determinants of recruitment success and dispersal distance for two important exploited species in Chile, and to provide the bases to advance recommendations for management and conservation in one the most productive, but also exploited, coastal regions in the world.
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Grange, Laura Joanne. "Reproductive success in Antarctic marine invertebrates". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/41355/.
Testo completoAbstract (sommario):
The nearshore Antarctic marine environment is unique, characterised by low but constant temperatures that contrast with an intense peak in productivity. As a result of this stenothermal environment, energy input has a profound ecological effect. These conditions have developed over several millions of years and have resulted in an animal physiology that is highly stenothermal and sometimes closely coupled with the seasonal food supply, e.g. reproductive periodicity and food storage. Therefore, Antarctic marine animals are likely to be amongst the most vulnerable species worldwide to environmental modifications and can be regarded as highly sensitive barometers for change. Reproductive success is a vital characteristic in species survival and evaluation of change in reproductive condition with time key to identifying vulnerable taxa. Characterising reproductive success with time is a major requirement in predicting species response to change and the early stages of species loss. Some invertebrates are highly abundant in shallow water sites around the Antarctic and form conspicuous members of the Antarctic benthos. Three common echinoderms and one nemertean were sampled from sites adjacent to the British Antarctic Survey’s Rothera Research Station, Adelaide Island, on the West Antarctic Peninsula between 1997-2001. Reproductive patterns were determined by histological analyses of gonad tissue. This study provided further evidence for inter-annual variation in Antarctic gametogenic development, which appeared to be driven to some extent by trophic position and reliance on the seasonal phytoplankton bloom. The largest variation in reproductive condition was demonstrated for the detritivorous brittle star, Ophionotus victoriae. The seasonal tempos of this echinoderm have been attributed in part, to the seasonal sedimentation events common in the high Antarctic. The reproductive patterns in the scavenging starfish, Odontaster validus and the predatory nemertean, Parborlasia corrugatus showed less inter-annual variation. The de-coupling of these invertebrates from the intensely seasonal phytoplankton bloom appeared to partially account for the reproductive trends observed. The lack of inter-annual variation in the reproduction of the filter-feeding sea-cucumber, Heterocucumis steineni, was somewhat counterintuitive, although problems with sample processing probably accounted for the majority of this anomaly. Echinoderms were also collected during the Antarctic summer field seasons in 2003 and 2004. A series of fertilisation success studies were undertaken comparing the adaptations in an Antarctic and an equivalent temperate starfish to achieve optimal numbers of fertilised eggs, and elemental analyses were used to estimate the nutritional and energetic condition of the bodily and reproductive tissues in two Antarctic echinoderms. Fertilisation studies indicated that Antarctic invertebrates require 1-2 orders of magnitude more sperm to ensure optimal fertilisation success. These sperm tended to be long-lived and capable of fertilising eggs 24+ hours after release. The study suggested that synchronous spawning, aggregations and specific pre-spawning behaviour are employed to help counter the deleterious effects of sperm limitation. The Antarctic eggs and sperm were also highly sensitive to even small modifications in temperature and salinity, affecting the number of eggs fertilised. Such stenothermy is of particular relevance if the 1-2ºC rise in global temperature, predicted over the next century, is realised. Biochemical composition of body components of two species of Antarctic echinoderm indicated a significant difference in the composition between the male and female gonad, particularly in the Antarctic brittle star Ophionotus victoriae. The ovaries contained a much larger proportion of lipid compared to the testes, and demonstrated a distinct seasonality in composition. Higher levels of lipid were observed in the ovary during the austral winter coincident with a period of reproductive investment and maturing oocytes in the gonad. O. victoriae exhibited lower amounts of lipid in the late austral spring suggesting the removal of mature oocytes from the ovary through spawning. The seasonality in composition and the high levels of lipid and protein measured in the ophiuroid gut tissue, suggested the gut might play a role in providing material and energy for metabolic function and possibly gametogenesis; higher lipid levels were apparent during the period of seasonal phytodetrital flux. The role of the pyloric ceaca in asteroids as a nutrient storage organ was also evident in the high levels of both protein and lipid observed in this bodily component in the star fish, Odontaster validus.
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Mohd, Zanuri Norlaila Binti. "The effects of environmental contaminants and ocean acidification on reproductive success in marine invertebrates". Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3638.
Testo completoAbstract (sommario):
Marine organisms are exposed to a range of environmental stressors, including anthropogenic pollutants and ocean acidification, which may have harmful effects. The reproductive processes of broadcast spawning marine invertebrates are considered to be particularly vulnerable to environmental insults. Predicting the potential impacts of ocean pollution and acidification on reproductive success is essential to anticipate the consequences of predicted marine change. This study evaluated the effects of exposure to the pharmaceutics diclofenac, ibuprofen and sildenafil citrate (Viagra), the metals cadmium and copper, and the endocrine disrupting compound nonylphenol (singly and under simulated ocean acidification scenarios; pH 8.1, 7.9 and 7.7) on sperm motility and fertilisation success of Asterias rubens, Psammechinus miliaris and Arenicola marina. Sperm motility was determined by Computer Assisted Sperm Analysis (CASA) and fertilisation success by the presence of embryonic cleavage at 60 minutes after fertilisation. Sperm motility (percentage of motile sperm and swimming speed) was reduced by nonylphenol concentrations ≥0.1μg/l, diclofenac ≥ 1.0μg/l, cadmium 1000μg/l, copper ≥10μg/l and ocean acidification of pH 7.9 and 7.7. Exposure to ≥ 1.0μg/l of ibuprofen only affected P. miliaris sperm. Exposure of sperm of A. rubens and P. miliaris to sildenafil citrate at concentrations ≥ 18ng/l and ≥ 50ng/l respectively increased both percentage motility and swimming velocity. Sperm pre-incubated in test conditions prior to fertilisation showed significant reductions in fertilisation success in all single pollutant and ocean acidification scenarios with the exception of ibuprofen for which only P. miliaris was negatively affected. Pre-incubation with sildenafil citrate significantly increased fertilisation success of A. rubens and P. miliaris but not for A. marina. Curiously, the pre-incubated oocytes of P. miliaris, A. rubens and A. marina appeared remarkably robust to some of the pollutants at ambient pH. However, fertilisation was significantly inhibited when exposed to diclofenac, copper, cadmium and seawater pH 7.9 and 7.7 as single stressors. Fertilisation success of P. miliaris and A. marina was adversely affected by sperm-oocyte incubation of ≥20 minutes with 100μg/l and 100μg/l of ibuprofen respectively. Combined nonylphenol and elevated seawater pH significantly reduced sperm motility and fertilisation success. These results demonstrate the potential for marine invertebrates to be affected by single pollutants and suggest that these effects may be more severe under predicted ocean acidification conditions.
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Suwandy, Jason. "Temporal Currency: Life-history strategies of a native marine invertebrate increasingly exposed to urbanisation and invasion". Thesis, University of Canterbury. School of Biological Sciences, 2012. http://hdl.handle.net/10092/7322.
Testo completoAbstract (sommario):
Biological invasions pose a serious threat to biodiversity world-wide. Through various means, such as competition or predation, invaders can radically change species composition and the functioning of native ecosystems. Even though our understanding of the mechanisms underlying invasion success is improving, there is still a lack of knowledge on the response of native species under pressure from invasion. This study adds to existing knowledge on the responses of a native species to invasion by non-indigenous species.
Pyura pachydermatina is a native ascidian in the southeast coast of New Zealand currently under pressure from increased urbanisation and invasion by other ascidian species. The
reproductive strategies employed by P. pachydermatina are investigated and the role of these strategies to increase its resistance to invasion are assessed. A population study on the status of P. pachydermatina around the Banks Peninsula was carried out in Camp Bay, Pigeon Bay, and Wainui. Spawning experiments using P. pachydermatina and gonad histology were done regularly during the one year study period to assess its ability to self-fertilise and determine
its reproductive period. In addition, predation experiments were carried out to assess the susceptibility of P. pachydermatina early life stages to two amphipod predators.
The surveys indicated that the populations of P. pachydermatina in the three sites are different from one another. Wainui has on average the largest individuals of P.
pachydermatina and Camp Bay, the smallest. Abundance of P. pachydermatina was highest in Pigeon Bay and lowest in Wainui. The three life stages of Pyura pachydermatina; recruits, juveniles, and adults, were present in all sites at all seasons. The spawning experiments confirmed the species’ ability to self-fertilise and that it has a year-round spawning period.
The two amphipod predators, Jassa marmorata and Caprella mutica, were efficient in consuming the egg and larval stages of P. pachydermatina, but did not feed on the settlers.
Year-round reproduction and the ability to self-fertilise potentially give P. pachydermatina increased resistance to the effects of urbanisation and invasion. This population study
suggested that the species is thriving around the Banks Peninsula. This, combined with previous studies on the non-indigenous ascidian Styela clava that stated the static or declining populations of the potential invaders, gives a positive outlook for the native species for the future. I suggest the use of genetic techniques to assess, in more detail, the population structure and dispersal potential of this native species. I also suggest constant monitoring of native species is required to keep up to date with the current status of the species, which will in turn help management decisions should regional spread of the Lyttelton S. clava invasion
occur in the future.
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Grémare, Antoine. "Aspects quantitatifs de la reproduction chez quelques annélides polychètes : Intérets et perspectives". Paris 6, 1988. http://www.theses.fr/1988PA066651.
Testo completoAbstract (sommario):
Etude au niveau de la strategie, physiologie et dynamique des aspects quantitatifs de la reproduction chez plusieurs annelides polychetes. L'auteur fournit egalement une description du cycle de e. Nebulosa dans la region de banyuls sur mer
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Tait, Richard. "Aspects physiologiques de la senescence post-reproductive chez Octopus vulgaris". Paris 6, 1986. http://www.theses.fr/1986PA066435.
Testo completoAbstract (sommario):
LLes changements qui ont lieu chez O. V. Pendant la période de senescence postreproductive sont examinés afin d'identifier les causes de la mort naturelle. L'analyse biochimique montre que la glande digestive et le muscle du manteau sont les plus affectés par la senescence. La mort naturelle d'Octopus vulgaris est due à l'action que les glandes optiques exercent sur le métabolisme protéique, action qui n'est modérée par aucune rétroaction.
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Sherman, Craig D. H. "The importance of fine-scale environmental heterogeneity in determing levels of genotypic diversity and local adaptation". Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060726.114643/index.html.
Testo completo
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Brassart, Michel. "Rôle des échanges ioniques membranaires lors de la reprise de la méiose de l'ovocyte de Barnea candida : mesures effectuées à l'aide de sondes fluorescentes". Paris 6, 1986. http://www.theses.fr/1986PA066390.
Testo completoAbstract (sommario):
Par une technique de marqueurs optiques, la concentration interne en ions calcium libres a été mesure, ainsi que le ph intracellulaire et le potentiel électrique de la membrane de l'ovocyte de Barnea candida. Un excès d'ions k**(+) externes entraine la reprise de la méiose qui s'accompagne d'un influx calcique et d'une augmentation du ph intracellulaire. Une base faible, NH4Cl, entraine la reprise de la méiose, une libération d'ions. Calcium et une alcalinisation du cytoplasme. L'augmentation intracellulaire du ph ne serait donc pas un facteur déclenchant l'activation mais constituerait un épiphénomène responsable de certaines réactions métaboliques ultérieures.
Libri sul tema "Marine invertebrates – Reproduction"
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Ostrovsky, Andrew. Evolution of Sexual Reproduction in Marine Invertebrates. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7146-8.
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Ostrovskiĭ, A. N. Evolution of sexual reproduction in marine invertebrates: Example of gymnolaemate bryozoans. Dordrecht: Springer, 2013.
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3
Strathmann, Megumi F. Reproduction and development of marine invertebrates of the northern Pacific coast: Data and methods for the study of eggs, embryos, and larvae. Seattle: University of Washington Press, 1987.
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Herbert, Wilson W., Stricker Stephen A e Shinn George Loren, a cura di. Reproduction and development of marine invertebrates. Baltimore: Johns Hopkins University Press, 1994.
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Giese, Arthur C., e John S. Pearse. Reproduction of Marine Invertebrates: Echinoderms and Lophophorates. Boxwood Pr, 1992.
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Giese, Arthur C., e John S. Pearse. Reproduction of Marine Invertebrates: General Aspects : Seeking Unity in Diversity. Blackwell Science Inc, 1988.
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Giese, Arthur C., e Vicki Pearse. Reproduction of Marine Invertebrates: General Aspects: Seeking Unity in Diversity. Boxwood Pr, 1987.
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Allen, Jonathan D., Adam M. Reitzel e William Jaeckle, a cura di. Asexual Reproduction of Marine Invertebrate Embryos and Larvae. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0005.
Testo completoAbstract (sommario):
Developmental plasticity during the early life histories of marine invertebrates is a fascinating opportunity to study the interplay between ecology and evolution. In particular, some embryos and larvae initiate asexual reproduction while completing their development. This chapter examines the mode, frequency, and taxonomic diversity of asexual reproduction that occurs between the zygotic and the juvenile stages. Special attention is given to the phylum Echinodermata, where asexual reproduction during embryonic and larval development has been best studied. An emphasis is also placed on the factors that have been identified as likely inducers of asexual reproduction and an assessment of the likelihood that asexual reproduction is an adaptive response to these factors. Lastly, several key open questions are identified as potential avenues for future research about the causes and consequences of asexual reproduction by the developmental stages of marine invertebrates.
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Andrew (Andrey N.) N. Ostrovsky. Evolution of Sexual Reproduction in Marine Invertebrates: Example of gymnolaemate bryozoans. Springer, 2016.
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M, Young Craig, e Eckelbarger Kevin J, a cura di. Reproduction, larval biology, and recruitment of the deep-sea benthos. New York: Columbia University Press, 1994.
Cerca il testo completoCapitoli di libri sul tema "Marine invertebrates – Reproduction"
1
Sköld, Helen Nilsson, Matthias Obst, Mattias Sköld e Bertil Åkesson. "Stem Cells in Asexual Reproduction of Marine Invertebrates". In Stem Cells in Marine Organisms, 105–37. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2767-2_5.
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Ostrovsky, Andrew. "Reproductive Patterns of Gymnolaemate Bryozoa: General Overview and Comparative Analysis". In Evolution of Sexual Reproduction in Marine Invertebrates, 1–113. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7146-8_1.
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Ostrovsky, Andrew. "Cheilostome Brood Chambers: Structure, Formation, Evolution". In Evolution of Sexual Reproduction in Marine Invertebrates, 115–228. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7146-8_2.
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Ostrovsky, Andrew. "Evolution of Reproductive Patterns in Cheilostomata". In Evolution of Sexual Reproduction in Marine Invertebrates, 229–82. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7146-8_3.
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Wangensteen, Owen S., Xavier Turon e Creu Palacín. "Reproductive Strategies in Marine Invertebrates and the Structuring of Marine Animal Forests". In Marine Animal Forests, 571–94. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-21012-4_52.
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Wangensteen, Owen S., Xavier Turon e Creu Palacín. "Reproductive Strategies in Marine Invertebrates and the Structuring of Marine Animal Forests". In Marine Animal Forests, 1–24. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-17001-5_52-1.
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Mercier, Annie, e Jean-François Hamel. "Lunar Periods in the Annual Reproductive Cycles of Marine Invertebrates from Cold Subtidal and Deep-Sea Environments". In Annual, Lunar, and Tidal Clocks, 99–120. Tokyo: Springer Japan, 2014. http://dx.doi.org/10.1007/978-4-431-55261-1_6.
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"Vitellogenin Synthesis in Marine Invertebrates Catherine Souty-Grosset". In Endocrinology and Reproduction, 215–60. CRC Press, 1997. http://dx.doi.org/10.1201/9781482287066-12.
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Dennenmoser, Stefan, John H. Christy e Martin Thiel. "Rhythms and Reproduction". In Reproductive Biology, 472–502. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190688554.003.0017.
Testo completoAbstract (sommario):
Reproductive rhythms can be found in numerous crustacean species. This chapter reviews the temporal scales of rhythms and how these rhythms are entrained and maintained by external cues and endogenous clocks. The occurrence and synchrony of rhythms vary along latitudinal and depth gradients, which may depend on the availability of zeitgebers (e.g., temperature and photoperiod), changing selective pressures such as predation risk, and variability in larval development rates that affect the timing and synchrony of reproductive rhythms. Commonly observed rhythms are reproductive migrations and synchronized larval release, which are often timed to reduce predation risk for newly hatched larvae. In crustaceans, reproductive rhythms rarely evolve under pure density-dependent selection for synchrony. Pure density dependence is common in marine broadcast-spawning invertebrates like corals, which rely on accumulation of gametes in time and space to ensure fertilization. Instead, (density-independent) selection for synchrony with environmental cycles that track changes in factors affecting fitness such as energy expenditure, predation risk, or food availability seems to be the rule, although some exceptions may exist. In contrast to natural selection, the possible contribution of sexual selection on reproductive rhythms has rarely been considered. Selection for enhanced mating possibilities should favor reproductive synchrony, but deviations from synchrony will affect the operational sex ratio and influence sexual selection. Finally, the chapter discusses the possibility of sexual conflict over reproductive timing between males and females and explores circumstances under which synchronous reproductive rhythms might be abandoned.
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Messina, Frank J., e Charles W. Fox. "Offspring Size and Number". In Evolutionary Ecology. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195131543.003.0014.
Testo completoAbstract (sommario):
If we look across all organisms, we find that some species produce only one or a few large offspring per reproductive bout (e.g., most birds and mammals), others produce 10s or 100s of intermediatesize offspring (e.g., most plants and insects), and yet others produce many 1000s of offspring (e.g., some marine invertebrates). How can we account for such broad variation? In this chapter, we review many of the environmental and demographic variables that influence the evolution of offspring size and number. In the first section, we discuss how the trade-off between offspring size and number is an important determinant of offspring size. An individual’s resources can be allocated to three basic functions— growth, somatic maintenance, or reproduction. Resources directed toward reproduction can in turn be used to produce either many small offspring or a few large offspring. Thus, for a fixed amount of resources available for reproduction, it necessarily follows that there is a trade-off between the number and size of offspring during a given bout of reproduction. Trade-offs between offspring size and number during a single reproductive bout are a primary determinant of offspring size for most semelparous organisms, which reproduce once in their lifetime (e.g., salmon and century plants). For iteroparous organisms, however, lifetime reproduction is divided into many discrete bouts, with intervening periods of no reproduction. Evolutionary explanations for the number and size of offspring in these organisms must also consider how reproductive effort during any one period affects future survival and reproduction. The second part of our chapter considers the evolution of offspring number among long-lived, iteroparous organisms, especially vertebrates. We focus on the clutch sizes of birds that produce altricial (nidicolous) young. Because each nestling requires much parental care, we expect strong selection toward producing the most appropriate number of offspring for a given environment. The trade-off between current and future reproduction can also affect semelparous animals if offspring must be distributed among scattered resources. Many insects, for example, lay eggs on small, discrete hosts, and their sedentary offspring often cannot move between hosts. A female that places too many eggs on a host faces the same diminishing returns as a bird that produces more nestlings than it can provision.