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Cyst Production (cyst + production)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

SEASONAL VARIABILITY OF THE ORGANIC-WALLED DINOFLAGELLATE CYST PRODUCTION IN THE COASTAL UPWELLING REGION OFF CAPE BLANC (MAURITANIA): A FIVE-YEAR SURVEY,

JOURNAL OF PHYCOLOGY, Issue 1 2010
Karin A. F. Zonneveld
A 5-year sediment trap survey in the upwelling area off Cape Blanc (NW Africa) provides information on the seasonal and annual resting cyst production of dinoflagellates, their sinking characteristics and preservation potential. Strong annual variation in cyst production characterizes the region. Cyst production of generally all investigated species, including Alexandrium pseudogonyaulax (Biecheler) T. Horig. ex T. Kita et Fukuyo (cyst genus Impagidinium) and Gonyaulax spinifera (Clap. et J. Lachm.) Diesing (cyst genus Nematosphaeropsis) was enhanced with increasing upper water nutrient and trace-element concentrations. Cyst production of Lingulodinium polyedrum (F. Stein) J. D. Dodge was the highest at the transition between upwelling and upwelling-relaxation. Cyst production of Protoperidinium americanum (Gran et Braarud) Balech, Protoperidinium monospinum (Paulsen) K. A. F. Zonn. et B. Dale, and Protoperidinium stellatum (D. Wall) Balech, and heterotrophic dinoflagellates forming Brigantedinium spp. and Echinidinium aculeatum Zonn., increased most pronouncedly during upwelling episodes. Production of Protoperidinium conicum (Gran) Balech and Protoperidinium pentagonum (Gran) Balech cysts and total diatom valves were related, providing evidence of a predator,prey relationship. The export cyst-flux of E. aculeatum, P. americanum, P. monospinum, and P. stellatum was strongly linked to the flux of total diatom valves and CaCO3, whereas the export production of Echinidinium granulatum Zonn. and Protoperidinium subinerme (Paulsen) A. R. Loebl. correlated with total organic carbon, suggesting potential consumption of diatoms, prymnesiophytes, and organic matter, respectively. Sinking velocities were at least 274 m · d,1, which is in range of the diatom- and coccolith-based phytoplankton aggregates and "slower" fecal pellets. Species-selective degradation did not occur in the water column, but on the ocean floor. [source]

Cyst Formation in a Freshwater Strain of the Choanoflagellate Desmarella moniliformis Kent

THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 5 2000
BARRY S. C. LEADBEATER
ABSTRACT. Cyst formation in a freshwater strain of the colonial freshwater Choanoflagellate Desmarella moniliformis Kent (Protozoa; Choanoflagellida) has been studied with light and electron microscopy for the first time. Batch cultures inoculated with motile vegetative cells start to produce cysts within 3 days during the exponential phase of growth. Cyst production proceeds until in late stationary phase there is a preponderance of cysts. Transfer of cysts to fresh medium results in limited excystment. Encystment involves the production of electron-dense fibrillar wall material, firstly around the neck of the cell and then around the posterior end. As the wall material is deposited the neck of the cell elongates and the dictyosome rotates from the horizontal to vertical plane. The number of mitochondrial profiles seen in individual sections of cells increases. Finally the neck of the cell is retracted, the flagellum and collar tentacles are withdrawn, and the bottom of the neck of the cyst wall is sealed with a diaphragm of wall material. Excystment, which has not been observed directly, appears to involve the disruption of the wall at the base of the neck, the remainder of the cyst wall remains intact. Comparisons are made between encystment in Desmarella and cyst development in other protists. [source]

SEASONAL VARIABILITY OF THE ORGANIC-WALLED DINOFLAGELLATE CYST PRODUCTION IN THE COASTAL UPWELLING REGION OFF CAPE BLANC (MAURITANIA): A FIVE-YEAR SURVEY,

Organic-walled dinoflagellate cyst production in relation to upwelling intensity and lithogenic influx in the Cape Blanc region (off north-west Africa)

PHYCOLOGICAL RESEARCH, Issue 2 2005
Ewa Susek
SUMMARY Fossil dinoflagellate cyst assemblages are increasingly used in paleoclimatic research to establish paleoenvi-ronmental reconstructions. To obtain reliable reconstructions, it is essential to know which physical factors influence the cyst production. Most information about the relationship between variations in physical parameters and cyst production is known from middle and higher latitudes. Information from the (sub)tropics is rare. To increase this information, the temporal variation in cyst assemblages from the upwelling area off north-west Africa (off Mauritania) has been compared to environmental conditions of the upper water column. Samples were collected by the sediment trap CB9, off north-west Africa (Cape Blanc, 21°15,2,N, 20°42,2,W) between 11 June 1998 and 7 November 1999 at 27.5-day intervals. Off Cape Blanc, upwelling occurs throughout the year with variable intensity. This region is also characterized by frequently occurring Saharan dust storms. Seasonal variations in dust input, upwelling intensity and sea surface temperature are reflected by the production of organic-walled dinoflagellate cyst assemblages. Several cyst taxa are produced throughout the sampling interval, with the highest fluxes at times of strongest upwelling relaxation and/or dust input (Echinidinium aculeatum Zonneveld, Echini-din ium delicatum Zonneveld, Echinidinium granulaturn Zonneveld, Echinidinium spp., Impagidinium aculeatum (Wall) Lentin et Williams, Impagidinium sphaeri-cum (Wall) Lentin et Williams, Protoperidinium americanum (Gran et Braarud) Balech, Protoperidinium stellatum (Wall in Wall et Dale) Rochon etal., Protoperidinium spp., Selenopemphix nephroides (Benedek) Benedek et Sarjeant and Selenopemphix quanta (Bradford) Matsuoka). Species such as, for example, Bitectatodinium spongium (Zonneveld) Zonneveld et Jurkschat and Impagidinium patulum (Wall) Stover et Evitt do not show any production pattern related to a particular season of the year or to specific environmental conditions in the upper water column. The production of cysts of Protoperidinium monospinum (Paulsen) Zonneveld et Dale is restricted to intervals with increased nutrient concentrations in upper waters when sea surface temperatures at the sampling site is below approximately 24°C. [source]