Environmental control of reproduction in Perinereis nuntia var. brevicirrus

1994 ◽  
Vol 74 (4) ◽  
pp. 903-918 ◽  
Author(s):  
J.D. Hardege ◽  
H.D. Bartels-Hardege ◽  
Y. Yang ◽  
B.L. Wu ◽  
M.Y. Zhu ◽  
...  
Keyword(s):  
Water Temperature ◽  
Rocky Shore ◽  
Sex Pheromones ◽  
Laboratory Experiments ◽  
Environmental Control ◽  
Early Morning ◽  
Early Summer ◽  
Coelomic Fluid ◽  
Spawning Behaviour ◽  
Perinereis Nuntia

Perinereis nuntia brevicirrus (Grube 1857), collected from a rocky shore at Qingdao (China) were cultured under different temperature, daylength and moonlight regimes. Ripe individuals were found in the field after an increase of water temperature in early summer, with a semilunar spawning peak from the beginning of June to the end of September. In laboratory experiments, daylength has no influence on maturation and reproduction. Temperature-controlled culture produces gravid, reproducing specimens at any time of the year after an increase in water temperature. For reproduction both sexual partners leave their burrows and swarm at the water surface in the early morning, performing a nuptial dance. The spawning behaviour, the nuptial dance and the release of gametes, are controlled by sex pheromones which are present in the coelomic fluid of mature worms. A sex pheromone from Platynereis dumerilü, 5-methyl-3-heptanone, is found in Perinereis nuntia brevicirrus and causes an increase in swimming activity during reproduction and the release of a small amount of sperm from males. This signal induces the release of eggs by the females followed by the release of masses of sperm by the male due to a second female pheromone.

scholarly journals Extreme Meteorological Events in a Coastal Lagoon Ecosystem: The Ria de Aveiro Lagoon (Portugal) Case Study

2021 ◽  
Vol 9 (7) ◽  
pp. 727
Author(s):  
José Fortes Lopes ◽  
Carina Lurdes Lopes ◽  
João Miguel Dias
Keyword(s):  
Water Temperature ◽  
Coastal Lagoon ◽  
Early Summer ◽  
Extreme Weather Events ◽  
Climate Change Scenarios ◽  
State Variables ◽  
Ria De Aveiro ◽  
Physical Conditions ◽  
Weather Events ◽  
The Impact

Extreme weather events (EWEs) represent meteorological hazards for coastal lagoon hydrodynamics, of which intensity and frequency are increasing over the last decades as a consequence of climate changes. The imbalances they generated should affect primarily vulnerable low-lying areas while potentially disturbing the physical balances (salt and water temperature) and, therefore, the ecosystem equilibrium. This study arises from the need to assess the impact of EWEs on the Ria de Aveiro, a lagoon situated in the Portuguese coastal area. Furthermore, it was considered that those events occur under the frame of a future sea-level rise, as predicted by several climate change scenarios. Two EWEs scenarios, a dry and an extremely wet early summer reflecting past situations and likely to occur in the future, were considered to assess the departure from the system baseline functioning. It was used as a biogeochemistry model that simulates the hydrodynamics, as well as the baseline physical and biogeochemistry state variables. The dry summer scenario, corresponding to a significant reduction in the river’s inflow, evidences a shift of the system to a situation under oceanic dominance characterized by colder and saltier water (~18 °C; 34 PSU) than the baseline while lowering the concentration of the nutrients and reducing the phytoplankton population to a low-level limit. Under a wet summer scenario, the lagoon shifted to a brackish and warmer situation (~21 °C, <15 PSU) in a time scale of some tidal periods, driven by the combining effect of the tidal transport and the river’s inflow. Phytoplankton patterns respond to variability on local and short-term scales that reflect physical conditions within the lagoon, inducing nutrient-supported growth. Overall, the results indicate that EWEs generate local and transient changes in physical conditions (namely salinity and water temperature) in response to the characteristic variability of the lagoon’s hydrodynamics associated with a tidal-dominated system. Therefore, in addition to the potential impact of changing physical conditions on the ecosystem, saline intrusion along the lagoon or the transfer of brackish water to the mouth of the system are the main consequences of EWEs, while the main biogeochemistry changes tend to remain moderate.

Size-fractionated surface phytoplankton in the Kara and Laptev Seas: environmental control and spatial variability

2021 ◽  
Vol 664 ◽  
pp. 59-77
Author(s):  
AB Demidov ◽  
IN Sukhanova ◽  
TA Belevich ◽  
MV Flint ◽  
VI Gagarin ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Primary Production ◽  
Water Temperature ◽  
Environmental Control ◽  
Size Structure ◽  
Total Carbon ◽  
The Arctic ◽  
Size Groups ◽  
Phytoplankton Size ◽  
Phytoplankton Size Structure

Climate-induced variability of phytoplankton size structure influences primary productivity, marine food web dynamics, biosedimentation and exchange of CO2 between the atmosphere and ocean. Investigation of phytoplankton size structure in the Arctic Ocean is important due to rapid changes in its ecosystems related to increasing temperature and declining sea ice cover. We estimated the contribution of surface micro-, nano- and picophytoplankton to the total carbon biomass, chlorophyll a concentration and primary production in the Kara and Laptev Seas and investigated the relationships of these phytoplankton size groups with environmental factors which determine their spatial variability. Additionally, we compared chlorophyll specific carbon fixation rate, specific growth rate and carbon to chlorophyll ratios among different phytoplankton size groups. The investigation was carried out from August to September 2018. Generally, picophytoplankton was dominant in terms of chlorophyll a and primary production in the whole study area. The spatial variability of phytoplankton size classes was influenced by river discharge and relied mainly on water temperature, salinity and dissolved silicon concentration. Microphytoplankton prevailed across the river runoff region under conditions of low salinity and relatively high water temperature, while picophytoplankton was predominant under conditions of high salinity and low water temperature. Our study is the first to characterize size-fractionated phytoplankton abundance in the Kara and Laptev Seas, and provides a baseline for future assessment of the response of Kara and Laptev Sea ecosystems to climate-induced processes using phytoplankton size structure.

The effects of age, temperature, light quantity and wavelength on the swimming behaviour of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae)

Parasitology ◽  
1992 ◽  
Vol 105 (1) ◽  
pp. 131-137 ◽  
Author(s):  
J. G. Rea ◽  
S. W. B. Irwin
Keyword(s):  
Life Span ◽  
Water Temperature ◽  
Light Source ◽  
Laboratory Experiments ◽  
Temperature Dependent ◽  
Release Point ◽  
Successful Transmission ◽  
Active Life ◽  
Light Quantity ◽  
Precipitous Decline

Laboratory experiments indicated that the active life-span of the cercariae of Cryptocotyle lingua was temperature-dependent. An increase in water temperature and population age both correlated with a tendency for the organisms to become decaudate. The larvae were strongly photoresponsive to lateral light but with time, horizontal swimming rates (HSRs) from release point to light source progressively declined. When measured over a range of light quantities, HSRs peaked at 30 μM/m2/s. HSRs were also influenced by water temperature. A rapid increase occurred up to 15 °C after which there was a precipitous decline. HSRs to coloured light were negatively correlated with increasing wavelength. When offered a choice between colours, cercariae favoured the shorter wavelengths. The implications of these responses for successful transmission are discussed.

scholarly journals Assessment of Water Quality and Thermal Stress for an Artificial Fish Shelter in an Urban Small Pond during Early Summer

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 139
Author(s):  
Chang Hyuk Ahn ◽  
Saeromi Lee ◽  
Ho Myeon Song ◽  
Jae Roh Park ◽  
Jin Chul Joo
Keyword(s):  
Water Quality ◽  
Thermal Stress ◽  
Water Temperature ◽  
Open Space ◽  
Phenomenological Study ◽  
Quality Parameters ◽  
Early Summer ◽  
Freshwater Ecosystem ◽  
Artificial Wetlands ◽  
Forced Circulation

: This study evaluated water quality variations in an artificial deep pool (ADP), which is an underground artificial structure built in a shallow pond as a fish shelter. The water temperature, pH, dissolved oxygen (DO), and electrical conductivity (EC) were measured on an hourly basis in the open space and inside the ADP, and a phenomenological study was performed, dividing seasons into normal and rainy seasons and environments into stagnant and circulating conditions. The results showed that the water quality parameters inside the ADP exhibit lower fluctuations and diurnal variations compared with the open space. On average, the water temperature inside the ADP is lower than outside it by 1.7–3.7 °C in stagnant conditions, and by 0.6–0.7 °C in circulating conditions during early summer. Thermal stratification occurs inside the ADP but is temporarily disturbed due to the mixing from the forced circulation and the rainwater input through rainfall events. The ADP provided a constant and optimal water temperature for living and spawning for bitterling (i.e., 15.0–21.0 °C), which dominated in experimental pond during spring to summer. Most importantly, the ADP was able to significantly reduce the thermal stress of the fish in the study site, and as a result, the bitterling, a cool water fish species, could successfully become dominant. Finally, the deployment of the ADP appears to provide a practical alternative for effective fishery resources management to improve species diversity and fish communities in an artificial freshwater ecosystem (garden pond, park pond, other artificial wetlands, etc.).

ʟ-Ovothiol A: The Egg Release Pheromone of the Marine Polychaete Platynereis Dumerilii: Annelida: Polychaeta

1999 ◽  
Vol 54 (12) ◽  
pp. 1145-1174 ◽  
Author(s):  
Ingo Röhl ◽  
Bernd Schneider ◽  
Bettina Schmidt ◽  
Erich Zeeck
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Sex Pheromones ◽  
Marine Invertebrates ◽  
Reversed Phase ◽  
Coelomic Fluid ◽  
Platynereis Dumerilii ◽  
Marine Polychaete ◽  
First Time ◽  
Sexually Mature

Sex pheromones, released with the coelomic fluid by male Platynereis dumerilii initiate egg release in swarming females. The egg release pheromone, isolated from the coelomic fluid of sexually mature males, was identified as ʟ-Ovothiol A, which was found in male marine invertebrates for the first time. Isolation was obtained by reversed-phase high-performance liquid chromatography in the biologically inactive disulfide form.

Spawning Behaviour and Development of Perinereis nuntia var. brevicirrus (Annelida: Polychaeta)

1995 ◽  
Vol 114 (1) ◽  
pp. 39 ◽  
Author(s):  
Jörg Detlef Hardege ◽  
Helga Dorothea Bartels-Hardege ◽  
Jorg Detlef Hardege
Keyword(s):  
Spawning Behaviour ◽  
Perinereis Nuntia

Research of Dinosaurs Weathering Mechanism in Zhucheng Shandong

2015 ◽  
Vol 723 ◽  
pp. 757-762 ◽  
Author(s):  
Shang Kun Zhang ◽  
Sheng Xian Du ◽  
Xue Feng Yu ◽  
Guo Rong Zhang ◽  
Xiang Yu Luo ◽  
...  
Keyword(s):  
Water Temperature ◽  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Reference Value ◽  
Scientific Basis ◽  
Geological Heritage ◽  
Physical Models ◽  
Process Water ◽  
Excavation Process ◽  
Weathering Process

In recent years, more and more domestic and international dinosaur fossils geological heritage were found, and many dinosaur fossils severe weathering within a few years after excavation.This study were based on Zhucheng dinosaur fossils ,the research of weathering mechanism of dinosaur fossils were from aspects of physical - mechanical characteristics.Means of laboratory experiments, physical models, theories and numerical experiments were used to explores the effect of weathering by the factors of excavation process, water, temperature , acidic substances and other factors on dinosaur fossils and relics.The results reveal the physical destruction of Shandong Zhucheng dinosaur fossils in the mechanism and characteristics of weathering process can provide theoretical and scientific basis for the protection of fossils, and other parts of the mechanism of weathering and protection of dinosaur fossils study provides reference value.

Spring breeding of a northern temperate crayfish, Orconectes rusticus

1982 ◽  
Vol 60 (11) ◽  
pp. 2641-2645 ◽  
Author(s):  
Michael Berrill ◽  
Michael Arsenault
Keyword(s):  
Water Temperature ◽  
Temperature Increase ◽  
Laboratory Experiments ◽  
Breeding Period ◽  
Orconectes Rusticus ◽  
Southern Ontario ◽  
Males And Females ◽  
Sexually Mature

In southern Ontario in the springs of 1980, 1981, and 1982 the crayfish Orconectes rusticus bred explosively when water temperatures rose above 4 °C. Copulations occurred frequently as sexually mature males and females wandered over the substrate at night. Males fought with each other and interrupted copulating pairs. In 1980 and 1981, females began to sequester themselves and extrude their eggs 11–12 days after copulations began. Males then gradually wandered and fought less, began feeding, and the breeding period ended approximately 4 weeks after the initiation of frequent copulations. In 1982, a delayed spring resulted in a far shorter breeding period. Laboratory experiments indicated that although a rise in water temperature initiated breeding events, including egg extrusion, the degree of necessary temperature increase may be inversely correlated with the duration of lengthening photoperiod to which females are exposed. Females which did not copulate in spring extruded eggs which were mostly infertile, emphasizing the importance of spring copulation in this northern orconectid.

scholarly journals Spatial and Temporal Variability of Rainfall in the Alps–Mediterranean Euroregion

2016 ◽  
Vol 55 (3) ◽  
pp. 655-671 ◽  
Author(s):  
Jean-François Rysman ◽  
Yvon Lemaître ◽  
Emmanuel Moreau
Keyword(s):  
Rainfall Variability ◽  
Convective Available Potential Energy ◽  
Small Region ◽  
Meridional Wind ◽  
Early Morning ◽  
Early Summer ◽  
Spatial And Temporal Variability ◽  
Model Output ◽  
Diurnal Variability ◽  
The Alps

AbstractThis study describes the main patterns of rainfall distribution in the Alps–Mediterranean “Euroregion” using a ground radar and characterizes the associated processes using model output. The radar dataset spans 2009–12 with fine spatial (1 km) and temporal (5 min) resolutions. The most significant rain accumulations were observed in 2009 and 2010, and the most intense extreme events occurred in 2010. Conversely, 2012 was a dry year. Model output revealed that the wind shear, the pressure, and the meridional wind at low level were the three main factors explaining the rainfall variability between 2009 and 2012. At the monthly scale, the maximum of rain accumulation was observed in November along the coast. Results also showed that the most intense rain rates were observed during early summer and autumn in the “Pre-Alps.” The monthly variability was characterized by a displacement of extreme rain events from land to sea from late spring to winter. Correlation analyses showed that this displacement was essentially controlled by the convective available potential energy (CAPE). Rainfall showed a diurnal variability from April to August for the land areas of the Alps–Mediterranean Euroregion. The diurnal variability was significant during the spring and summer months, with maximal rain intensity between 1600 and 1800 UTC. The correlation of the rainfall with CAPE showed that this cycle was related to atmospheric instability. A secondary peak in average rain rate was observed during the early morning and was likely triggered by land breezes. The results highlighted that rainfall characteristics are extremely diverse in terms of intensity and distribution in this relatively small region.

Stomatal conductance in three conifer species at different elevations during summer in Wyoming

1988 ◽  
Vol 18 (2) ◽  
pp. 242-246 ◽  
Author(s):  
Gregory A. Carter ◽  
William K. Smith ◽  
Julian L. Hadley
Keyword(s):  
Air Temperature ◽  
Early Morning ◽  
Early Summer ◽  
Subalpine Forest ◽  
Daily Maximum ◽  
Interspecific Differences ◽  
Lower Elevation ◽  
Central Rocky Mountains ◽  
Maximum Conductance ◽  
Minimum Air Temperature

Stomatal conductances to water vapor diffusion in Engelmann spruce (Piceaengelmannii Parry ex Engelm.), subalpine fir (Abieslasiocarpa (Hook.) Nutt.), and lodgepole pine (Pinuscontorta Engelm.) were compared to determine environmental influences on conductance at higher (3220 m) and lower (2860 m) elevations in the central Rocky Mountains. Measurements were taken on clear days, and soil water potentials remained at or greater than −0.1 MPa. Interspecific differences were small between spruce and fir at either site, but pine conductance was generally higher than spruce or fir at 2860 m. Daily maximum conductance in spruce and fir at 3220 m did not increase above 1.0 mm s−1 until daily minimum air temperature (early morning) increased to near 1 °C in early summer. Increases in maximum conductance above 2.0 mm s−1 occurred at both elevations when minimum air temperature rose above approximately 5 °C. At the lower elevation site, increases in maximum conductance during late July and mid-August appeared to depend strongly on soil temperature increasing above 7–8 °C. The persistence of cold soil temperatures in the highest elevations of the subalpine forest may serve to inhibit stomatal opening in spruce and fir in comparison to spruce, fir, and pine in lower elevation forests.

Sign in / Sign up

Export Citation Format

Share Document