Beiträge zur sexualbiologie der littorinen

Linke, Otto

doi:10.1007/bf00424082

Cited by 12 publications

(6 citation statements)

References 2 publications

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“…Spawn masses were usually oval in outline with a mean length of 4-38 mm and breadth 2-59 mm. No irregular, reniform units of the type often found in L. obtusata (Linke, 1934) were recorded. The egg size was within the range 250-297 /im or 531-563 lira.…”

Section: Spawning and Development L Pallidulamentioning

confidence: 76%

The Population Biology ofLacuna Pallidula(Da Costa) andLacuna Vincta(Montagu) in North-East England

Smith

1973

J. Mar. Biol. Ass.

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L. pallidula is more or less confined to Fucus serratus. L. vincta is common on F. serratus but is also found on Halidrys, Laminaria and various Rhodophyceae. Neither species occurs in the absence of these weeds on which they both feed and spawn. Lacuna species are the dominant gastropods on weed at M.L.W.S. at Whitburn, County Durham.Both species are annuals. In L. pallidula the growth rates of females and males are markedly different, the former growing both faster and over a longer period. Females attain a mean maximum size of 8–4 mm compared with 45 mm for males. L. vincta males and females grow at approximately the same rate, though females usually attain a greater size.Males predominate in L. pallidula at all times of the year, comprising between 55% and 75% of the population with a mean of 68–6%. Males die slightly sooner than females but there is no more than 4 weeks difference in longevity. Copulation in L. pallidula begins in November and continues to April, with two peaks in January and March.Spawning commences in January in both species and reaches its peak by April in L. pallidula and by June in L. vincta. Hatching occurs in L. pallidula from April to July. The time of first hatching in L. vincta is not certain but is probably about March. Larval settlement occurs from June to October with a maximum in September.Density is high following hatching in L. pallidula (> 2000/m2) and settlement in L. vincta (> 300/m2). Dispersion is similar in the two species, being aggregated at high density and more or less random at low density.

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Section: Spawning and Development L Pallidulamentioning

confidence: 76%

The Population Biology ofLacuna Pallidula(Da Costa) andLacuna Vincta(Montagu) in North-East England

Smith

1973

J. Mar. Biol. Ass.

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“…The experiment with snails which were overgrown with barnacles but had these removed before the start of the experiment suggests that this process was not responsible for the experimental outcome, although on a longer time scale this process ultimately increases in importance; (3) we suggest that copulation in these dioecious snails was hampered by the voluminous and prickly cover of barnacles. For copulation, the male crawls onto the shell of the female and then inserts his penis into the mantle cavity of the female underneath (Linke 1933). Thus, copulation depends on unimpaired mobility in the case of the male and a clean shell in the case of the female.…”

Section: Reproductionmentioning

confidence: 99%

Effects of barnacle epibionts on the periwinkle Littorina littorea (L.)

Buschbaum

Reise

1999

Helgol Mar Res

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In a sandy bay with mussel beds in the Wadden Sea (Island of Sylt, eastern North Sea), periwinkles Littorina littorea (L.) were often strongly overgrown with the barnacle Balanus crenatus Bruguière in the lower intertidal zone. Consequences of this epibiosis on mobility, reproduction and mortality of the snail were examined. B. crenatus growing on L. littorea increased snail volume up to 4-fold and weight up to 3.5-fold and crawling speed of fouled L. littorea was significantly slowed down. The epibiotic structure also caused a decrease in reproductive output. In laboratory experiments, egg production of fouled L. littorea was significantly lower than in snails free of barnacles. Presumably, copulation of the periwinkles is hampered by the voluminous and prickly cover of barnacles. Field studies demonstrated an increased mortality of overgrown L. littorea. A decrease in reproductive output and a lower survival of snails with a cover of barnacles suggest that B. crenatus epibionts may have a significant impact on the population of L. littorea.

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“…However, due to the limited availability and high cost of these sensors, turbidity is typically quantified, characterized, and estimated using broadband irradiance measurements, a more cost-effective method, and various turbidity factors and indices such as the Linke turbidity factor, the Ångström turbidity coefficient, the Schüepp turbidity factor, and the Unsworth-Monteith turbidity coefficient [14,15,20,35,38,39]. Among these, the most frequently used are the Linke turbidity factor (Linke, 1922) [40] and the Ångström turbidity coefficient [41]. The Linke turbidity factor describes the entire spectrum and quantifies the optical thickness of the atmosphere caused by the absorption and scattering of solar radiation by water vapor and aerosol particles in the visible and near-infrared regions relative to a dry and clean atmosphere [4,11,20,35,[42][43][44].…”

Section: Introductionmentioning

confidence: 99%

The Variation in Atmospheric Turbidity over a Tropical Site in Nigeria and Its Relation to Climate Drivers

SoneyeArogundade,

Rappenglück

2024

Atmosphere

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Atmospheric turbidity exhibits substantial spatial–temporal variability due to factors such as aerosol emissions, seasonal changes, meteorology, and air mass transport. Investigating atmospheric turbidity is crucial for climatology, meteorology, and atmospheric pollution. This study investigates the variation in atmospheric turbidity over a tropical location in Nigeria, utilizing the Ångström exponent (α), the turbidity coefficient (β), the Linke turbidity factor (TL), the Ångström turbidity coefficient (βEST), the Unsworth–Monteith turbidity coefficient (KAUM), and the Schüepp turbidity coefficient (SCH). These parameters were estimated from a six-month uninterrupted aerosol optical depth dataset (January–June 2016) and a one-year dataset (January–December 2016) of solar radiation and meteorological data. An inverse correlation (R = −0.77) was obtained between α and β, which indicates different turbidity regimes based on particle size. TL and βEST exhibit pronounced seasonality, with higher turbidity during the dry season (TL = 9.62 and βEST = 0.60) compared to the rainy season (TL = 0.48 and βEST = 0.20) from May to October. Backward trajectories and wind patterns reveal that high-turbidity months align with north-easterly air flows from the Sahara Desert, transporting dust aerosols, while low-turbidity months coincide with humid maritime air masses originating from the Gulf of Guinea. Meteorological drivers like relative humidity and water vapor pressure are linked to turbidity levels, with an inverse exponential relationship observed between normalized turbidity coefficients and normalized water vapor pressure. This analysis provides insights into how air mass origin, wind patterns, and local climate factors impact atmospheric haze, particle characteristics, and solar attenuation variability in a tropical location across seasons. The findings can contribute to environmental studies and assist in modelling interactions between climate, weather, and atmospheric optical properties in the region.

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Beiträge zur sexualbiologie der littorinen

Cited by 12 publications

References 2 publications

The Population Biology ofLacuna Pallidula(Da Costa) andLacuna Vincta(Montagu) in North-East England

The Population Biology ofLacuna Pallidula(Da Costa) andLacuna Vincta(Montagu) in North-East England

Effects of barnacle epibionts on the periwinkle Littorina littorea (L.)

The Variation in Atmospheric Turbidity over a Tropical Site in Nigeria and Its Relation to Climate Drivers

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