Grazing of Heterotrophic Dinoflagellate Noctiluca Scintillans (Mcartney) Kofoid on Gymnodinium Catenatum Graham
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Revista Latinoamericana de Microbiología Volumen Número Enero-Junio Volume 47 Number 1-2 January-June 2005 Artículo: Grazing of heterotrophic dinoflagellate Noctiluca scintillans (Mcartney) kofoid on Gymnodinium catenatum Graham Derechos reservados, Copyright © 2005: Asociación Mexicana de Microbiología, AC Otras secciones de Others sections in este sitio: this web site: ☞ Índice de este número ☞ Contents of this number ☞ Más revistas ☞ More journals ☞ Búsqueda ☞ Search edigraphic.com MICROBIOLOGÍA ORIGINAL ARTICLE cana de i noamer i sta Lat Grazing of heterotrophic dinoflagellate Noctiluca i Rev Vol. 47, No. 1-2 scintillans (Mcartney) Kofoid on Gymnodinium January - March. 2005 April - June. 2005 pp. 06 - 10 catenatum Graham Rosalba Alonso Rodríguez,* José Luis Ochoa,** Manuel Uribe Alcocer*** ABSTRACT. A dinoflagellate bloom (“red tide” event) dominated RESUMEN. Un evento de proliferación de dinoflagelados (“marea by the toxic Gymnodinium catenatum Graham (Gymnodiniales, Di- roja”) dominado por el dinoflagelado tóxico Gymnodinium catenatum nophyceae; 99.7%) and the noxious Noctiluca scintillans (Mcartney) Graham (Gymnodiniales, Dinophyceae; 99.7%) y el dinoflagelado Kofoid (Noctilucaceae, Dinophyceae; 0.3%) was observed in Bahía nocivo Noctiluca scintillans (Mcartney) Kofoid (Noctilucaceae, Di- de Mazatlán Bay, México, on 24-26 January 2000. Photographic and nophyceae; 0.3%) fue observado en la Bahía de Mazatlán, Sin., microscopic analysis of samples during such an event, allowed us to México, del 24 al 26 de enero del 2000. El análisis fotográfico y mi- collect evidence of a marked The particularity of grazing of G. cate- croscópico de muestras obtenidas durante el evento nos permitió do- natum by by N. scintillans cells, suggesting a mechanism of “biocon- cumentar una marcada depredación de N. scintillans sobre G. catena- trol” between these species that may contribute to attenuate a poten- tum, lo que sugiere un mecanismo de “biocontrol” entre estas tially toxic phenomenon under natural conditions. especies que puede contribuir a atenuar un fenómeno potencialmente tóxico en condiciones naturales. Key words: Biocontrol, Gymnodinium catenatum, grazing, Noctiluca Palabras clave: Biocontrol, depredación, Gymnodinium catenatum, scintillans, red tides. “mareas rojas”, Noctiluca scintillans. INTRODUCTION partly responsible for the noxious effect of such events.10,12,22 The fish, for example, would have to use Mazatlan Bay in Mexico is an open, eutrophic and sub- more O2 in the action of pumping water thant the amount tropical coastal embayment, located on the Southeast Gulf they could extract from the pumped water, thus dying be- of California (Fig. 1). In the summer, it is influenced by 9 cause of O2 deficiency. Also, if the polymers stick to the tropical waters, and in the winter by sporadic NW domi- epithelia of the gill lamellae, thus narrowing the pores, an 1 nant winds that induce upwelling. Red tides are common increase in flow resistance can be anticipated and, there- in Mazatlan Bay at the end of the winter and the beginning fore, the diffusion of O2 and other substances results affect- of the spring. Harmful dinoflagellates, such as Gymnodini- ed.; in addition, mucus secretion by the fish, as a defense um catenatum Graham and Noctiluca scintillans (Mcart- mechanism against macromolecular adhesion, would itself ney) Kofoid, have been reported occurring separately in increase flow resistance of the viscous water, even further the area in various red tide episodes in the last two de- jeopardizing the fish survival.9 3,17 cades. However, the red tide event observed on January G. catenatum is a chain-forming dinoflagellate, usually 24-26, 2000, dominated by the coexistence of these two with 8-16 and up to 64 cells, and notorious for its associa- species and perceived as a brownish to dark purple color tion with Paralytic Shellfish Poisoning (PSP) events world- pigmentation patch, with a high viscosity in the water col- wide. Its distribution includes cold-temperate, warm-tem- umn, was unusual in terms of duration and composition. perate and tropical regions.2,6 The optimal conditions for Increase in sea water viscosity is frequently associated with G. catenatum growth vary for each strain, making the tem- phytoplankton blooms.9 Both, G. catenatum and N. scintil- perature a determinant variable in the biogeography of the lans, are capable of producing exopolymers that may be different ecotypes, and in the creation of the optimal envi- ronmental window for its seasonal blooms.7 Such blooms coincide with upwelling-downwelling sequences within a * Universidad Politécnica de Sinaloa. Paseo de Niños Héroes # 1413 Esq. Consti- short-time scale, and recurrence relies on its capacity to tución, Centro Histórico, Mazatlán, Sinaloa, C.P. 82000. ** Graduate Program. Centro de Investigaciones Biológicas del Noroeste S.edigraphic.com C. Apdo. produce cysts when the water column conditions are unfa- Postal 128 La Paz, B.C.S., México, C.P. 23000. vorable.7,23 N. scintillans, on the other hand, is a het- *** Unidad Académica de Ecología Marina. Instituto de Ciencias del Mar y Lim- erotrophic, large (up to 1,000 m), obloid, and luminescent nología, Universidad Nacional Autónoma de México. µ dinoflagellate, also frequently involved in red tide events.4 Received September 1, 2004; received in revised form January 7, 2005; accepted Jan- It is considered non-toxic but is responsible for fish and uary 20, 2005. benthic fauna mortalities associated with anoxia and ex- Alonso et al Grazing in red tides 7 Rev Latinoam Microbiol 2005; 47 (1-2): 06-10 106°30´ 106°25´ 23°15´ Mazatlan 23°15´ City Mexico Gulf of California X 23°10´ 23°10´ Figure 1. Location of study area and collection site. creted ammonia produced by this organism.5,25 Environ- most abundant species. Various aliquots were fixed with an mental factors, such as temperature and salinity, determine acid solution (Lugol 1:100) and stored in 500-ml plastic the extension and intensity of N. scintillans blooms, being bottles in darkness for counting. Cell abundances were esti- 21-24°C, and salinities between 21-25 ppt, optimum for mated in a Sedgwick-Rafter chamber:rop (at 40X odarobale and 100X), FDP growth.14 At the end of a N. scintillans bloom, the large and the cell diameter measured using a scale included in amounts of ammonia concentrated inside the cells pro- the ocular. PhotographsVC of edfixed AS, material cidemihparG were taken with a sustraídode-m.e.d.i.g.r.a.p.h.i.cmotes their accumulation at the sea surface, thus making compound microscope (Mod. ICCA, Leyca, Heerbrogg, cihpargidemedodaborthem visible as a red tide phenomenon.4,18 N. scintillans Switzerland) using an achromatic light source,arap a drawing blooms are frequently observed in all major upwelling re- tube, a digital camera (Mod. DMLB, Leyca, Heerbrogg, gions and their sudden decline is related to endogenous cir- Switzerland),acidémoiB and an arutaretiLIM1000 software :cihpargideM (Leyca, Heerbrogg, cannual rhythms, triggered by light-dark changes and pre- Switzerland). Biovolume ratio (N. scintillans vs G. catena- dation by adult copepods and medusae. Temperature, light, sustraídode-m.e.d.i.g.r.a.p.h.i.ctum), was determined as suggested by Hillenbrand et al.8 wind, and currents, appear to determine the seasonal ap- pearance of N. scintillans worldwide.24 RESULTS In an attempt to characterize the event registered in Mazatlán Bay on January 24-26, 2000, we determine the The conditions prevailing inat Mazatlan Bay on January prevailing hydrological conditions, the composition, and 24-26, 2000 (Fig. 2), showed an ambient average tempera- the cell density of the bloom to conclude that, in spite of its ture at the sampling site of 19.3ºC, with a maximum of low abundance, the preying activity of N. scintillans ap- 25ºC and a minimum of 13ºC, at the surface and bottom of peared to be the main factor controlling the development of the water column, respectively. Wind strength and direc- a potentially harmful G. catenatum bloom. tion was 1.4 m/sec, NNW, and the low upwelling index es- timated (CUI, Coastal Upwelling Index) indicated the situ- MATERIALS AND METHODS ation of a calm conditions day in the area of study. Day length on such a date, provided 10 h of solar incidental Meteorological and hydrological conditions, suchedigraphic.com as light, and was the second highest irradiation of that month. ambient temperature variation, wind strength and direction, The densities of the most abundant species, G. catenatum and upwelling index, were determined as recommended by and N. scintillans were 1, 300 cells ml-1 (S = 409.06), and 4 Lluch-Cota.13 Surface water samples were collected with a cells ml-1 (S = 0.57), respectively. G. catenatum cell size van Dorn sampling bottle and examined by optical micros- distribution was bimodal with specimens measuring be- copy, at 200X and 400X, thus allowing identification of the tween 20-35 mm and 25-40 mm in diameter, while N. scin- 8 Alonso et al Grazing in red tides Rev Latinoam Microbiol 2005; 47 (1-2): 06-10 MG tillans cells were 10 times larger (220-500 mm in diame- nately, its sudden appearance and briefness, did not allow to ter). With these data, the biovolume ratio of G. catenatum record the process of the active feeding of N. scintillans over vs N. scintillans was approximately 1: 10,000. G. catenatum, nor to determine the rate of ingestion in situ. Photographs in Figure 3c-e indicate the grazing activity of We presume that the predation of G. catenatum by N. scintil- N. scintillans on G. catenatum during such an event. Unfortu- lans contributed to ending the bloom within a short interval. 24 Air a) 22 Depht 20 18 Temperature °C Temperature 16 6 Direction b) 10 4 8 2 6 Speed 0 4 -2 Prevailing wind (knots) Prevailing 2 component (knots) Southward -4 0 -6 30 c) t line 20 10 0 × 100 m coas -10 Figure 2.