Patterns of comb row development in young and adult stages of the ctenophores Mnemiopsis leidyi and Pleurobrachia pileus

2012 ◽  
Vol 273 (9) ◽  
pp. 1050-1063 ◽  
Author(s):  
Sidney L. Tamm
Keyword(s):  
Mnemiopsis Leidyi ◽  
Pleurobrachia Pileus

scholarly journals Does the Invasive Predator Mnemiopsis leidyi A. Agassiz, 1868 Control Copepod Abundances in the Seine Estuary?

2021 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Spatial Distribution ◽  
Coastal Waters ◽  
Mnemiopsis Leidyi ◽  
Seine Estuary ◽  
English Channel ◽  
Western Atlantic ◽  
Dramatic Decline ◽  
Pleurobrachia Pileus ◽  
Negative Effect ◽  
First Time

The indigenous ctenophore Pleurobrachia pileus (O.F. Müller, 1776) was common in the coastal waters of the English Channel in the early 1990s and showed very abundant populations in the downstream part of the Seine estuary. In 2005, the non-indigenous ctenophore Mnemiopsis leidyi A. Agassiz, 1868, a species native to the Western Atlantic, was reported for the first time in Europe in Norwegian fjords and in Le Havre harbour (Seine estuary, France). More recently, in 2017, both Pleurobrachia pileus and Mnemiopsis leidyi were recorded during suprabenthos and zooplankton sampling in the Seine estuary along a downstream-upstream transect. Both species show more abundant populations in May than in September. Conversely, copepods show a spatial distribution depending on the ctenophore distribution, with low copepod abundances in the downstream part of the estuary being associated with high ctenophore abundances, while high copepod abundances are recorded where ctenophores are absent or display low abundances. We propose that the intense predation of ctenophores on copepods is related to changes in hydrological conditions over the two last decades. This may explain the dramatic decline of copepod abundance in the Seine estuary, which could have a negative effect on its nursery role.

The role of Ca2+ in deflection-induced excitation of motile, mechanoresponsive balancer cilia in the ctenophore statocyst.

1997 ◽  
Vol 200 (11) ◽  
pp. 1593-1606 ◽  
Author(s):  
B Lowe
Keyword(s):  
Beat Frequency ◽  
Mnemiopsis Leidyi ◽  
Directional Sensitivity ◽  
Free Medium ◽  
Ciliary Beating ◽  
Graded Responses ◽  
Neural Input ◽  
High K ◽  
Pleurobrachia Pileus

Motile, mechanoresponsive cilia (balancers) in ctenophore statocysts, like vertebrate hair cells, are excited or inhibited depending upon the direction in which they are deflected. Balancers, however, may become either excited (beat rapidly) or inhibited (beat slowly) by deflection in the same direction, depending on the sign of ctenophore geotaxis (positive or negative). The beat frequency of many cilia is controlled by concentrations of Ca2+, membrane potential and neural input. How these factors affect deflection-induced ciliary beating in balancers was investigated. Deflection-induced excitation of balancers in whole Mnemiopsis leidyi larvae and dissected adult (Mnemiopsis leidyi, Pleurobrachia pileus) statocysts was reversibly inhibited by the Ca2+ channel inhibitors Co2+, Mg2+, Ni2+, and Mn2+. Deflection-induced excitation in balancers of isolated adult M. leidyi balancer groups was also inhibited by Co2+ or by Ca(2+)-free medium. Isolated balancer group cilia, like balancer cilia of intact ctenophores, exhibited responses to either sign of geotaxis and graded responses to deflection. Isolated balancers that were chemically depolarized in high-[K+], Ca(2+)-free medium were excited by local application of Ca2+ onto the ciliary bases, but not onto the cell bases or the ciliary tips. It is proposed that deflection-induced excitation of balancers is due to influx of Ca2+ through stretch- and voltage-activated channel activity. The sign of geotaxis of whole larvae and dissected adult statocysts was switched by electrical stimulation. Thus, neural input may participate in reversing the directional sensitivity of balancer cells.

First record of Beroe gracilis Künne, 1939 (Ctenophora: Beroida: Beroidae) from Norway, found in a Mnemiopsis leidyi A. Agassiz, 1865 bloom

2015 ◽  
Vol 8 ◽  
Author(s):  
Halldis Ringvold ◽  
Tamara A. Shiganova ◽  
K. Emily Knott ◽  
Bella S. Galil
Keyword(s):  
First Record ◽  
South Coast ◽  
Mnemiopsis Leidyi ◽  
The South ◽  
Western Norway ◽  
Pleurobrachia Pileus ◽  
The Common

In September 2014 an unusual mixture of ctenophores was recorded at Arboretet, south-western Norway and at Flødevigen, near Arendal on the south coast of Norway. In addition to the invasive American lobate ctenophore,Mnemiopsis leidyi, the common northern lobate ctenophoreBolinopsis infundibulumand the cydippidPleurobrachia pileus, two beroid ctenophores, were noted –Beroe cucumisandBeroegracilis. The latter species had not been documented before in Norwegian waters.

scholarly journals Scyphomedusae and Ctenophora of the Eastern Adriatic: Historical Overview and New Data

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 186
Author(s):  
Branka Pestorić ◽  
Davor Lučić ◽  
Natalia Bojanić ◽  
Martin Vodopivec ◽  
Tjaša Kogovšek ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Seasonal Pattern ◽  
Geographical Location ◽  
Distribution Patterns ◽  
Mnemiopsis Leidyi ◽  
Future Studies ◽  
Phenological Data ◽  
Pelagia Noctiluca ◽  
Regional Trends ◽  
Clear Seasonal Pattern

One of the obstacles to detecting regional trends in jellyfish populations is the lack of a defined baseline. In the Adriatic Sea, the jellyfish fauna (Scyphozoa and Ctenophora) is poorly studied compared to other taxa. Therefore, our goal was to collect and systematize all available data and provide a baseline for future studies. Here we present phenological data and relative abundances of jellyfish based on 2010–2019 scientific surveys and a “citizen science” sighting program along the eastern Adriatic. Inter-annual variability, seasonality and spatial distribution patterns of Scyphomedusae and Ctenophore species were described and compared with existing historical literature. Mass occurrences with a clear seasonal pattern and related to the geographical location were observed for meroplanktonic Scyphomedusae Aurelia solida, Rhizostoma pulmo, and to a lesser extent Chrysaora hysoscella, Cotylorhiza tuberculata and Discomedusa lobata. Holoplanktonic Pelagia noctiluca also formed large aggregations, which were seasonally less predictable and restricted to the central and southern Adriatic. Four species of Ctenophora produced blooms limited to a few areas: Bolinopsis vitrea, Leucothea multicornis, Cestum veneris and the non-native Mnemiopsis leidyi. However, differences between Adriatic subregions have become less pronounced since 2014. Our results suggest that gelatinous organisms are assuming an increasingly important role in the Adriatic ecosystem, which may alter the balance of the food web and lead to harmful and undesirable effects.

Population development of the invader ctenophore Mnemiopsis leidyi , in the Black Sea and in other seas of the Mediterranean basin

2001 ◽  
Vol 139 (3) ◽  
pp. 431-445 ◽  
Author(s):  
Shiganova T. ◽  
Mirzoyan Z. ◽  
Studenikina E. ◽  
Volovik S. ◽  
Siokou-Frangou I. ◽  
...  
Keyword(s):  
Black Sea ◽  
Mediterranean Basin ◽  
The Black Sea ◽  
Mnemiopsis Leidyi ◽  
Population Development ◽  
The Mediterranean ◽  
The Mediterranean Basin

scholarly journals Evidence of Diel Vertical Migration in Mnemiopsis leidyi

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e86595 ◽  
Author(s):  
Matilda Haraldsson ◽  
Ulf Båmstedt ◽  
Peter Tiselius ◽  
Josefin Titelman ◽  
Dag L. Aksnes
Keyword(s):  
Vertical Migration ◽  
Diel Vertical Migration ◽  
Mnemiopsis Leidyi
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