|Title||Physico-chemical and biological factors influencing dinoflagellate cyst production in the Cariaco Basin|
|Author||Bringué, M; Thunell, R C; Pospelova, V; Pinckney, J L; Romero, O E; Tappa, E J|
|Source||Biogeosciences vol. 15, issue 8, 2018 p. 2325-2348, https://doi.org/10.5194/bg-15-2325-2018 (Open Access)|
|Alt Series||Natural Resources Canada, Contribution Series 20180015|
|Media||paper; on-line; digital|
|File format||pdf (Adobe® Reader®); docx (Microsoft® Word®)|
|Area||Caribbean Sea; Venezuela (Bolivarian Republic of)|
|Lat/Long WENS|| -66.2500 -64.0000 11.2500 10.0000|
|Subjects||environmental geology; paleontology; marine organisms; oceanography; environmental studies; marine environments; palynological analyses; ecology; systematic paleontology; micropaleontology; taxonomy;
depositional environment; sedimentary environment; statistical analyses; microfloral assemblages; microfaunal assemblages; silica; basin analyses; sedimentary basins; Cariaco Basin; Intertropical Convergence Zone; Canal Centinela; Canal de la
Tortuga; Unare Platform; Dinoflagellates; Plankton; Phytoplankton; Zooplankton; North Atlantic Oscillation; El Niño-Southern Oscillation; Diatoms; microbiology; ocean circulation; seasonal upwelling; cyst production; biogenic silica|
|Illustrations||location maps; geoscientific sketch maps; tables; profiles; bar graphs; pie charts; histograms; graphs; plots; time seriea|
|Program||Science laboratory network, Science laboratory network coordination|
|Program||NSERC Natural Sciences and Engineering Research Council of
|Released||2018 04 19|
|Abstract||We present a 2.5-year-long sediment trap record of dinoflagellate cyst production in the Cariaco Basin, off Venezuela (southern Caribbean Sea). The site lies under the influence of wind-driven, seasonal
upwelling which promotes high levels of primary productivity during boreal winter and spring. Changes in dinoflagellate cyst production is documented between November 1996 and May 1999 at ~14-day intervals and interpreted in the context of in situ
observations of physico-chemical and biological parameters measured at the mooring site.|
Dinoflagellate cyst assemblages are diverse (57 taxa) and dominated by cyst taxa of heterotrophic affinity, primarily Brigantedinium spp. (51% of the total
trap assemblage). Average cyst fluxes to the trap are high (17.1x1000 cysts m(-2) day(-1)/ and show great seasonal and inter-annual variability. On seasonal timescales, dinoflagellate cyst production responds closely to variations in upwelling
strength, with increases in cyst fluxes of several protoperidinioid taxa observed during active upwelling intervals, predominantly Brigantedinium spp. Cyst taxa produced by autotrophic dinoflagellates, in particular Bitectatodinium spongium, also
respond positively to upwelling. Several "spiny brown" cysts contribute substantially to the assemblages, including Echinidinium delicatum (9.7 %) and Echinidinium granulatum (7.3 %), and show a closer affinity to weaker upwelling conditions. The
strong El Niño event of 1997/98 appears to have negatively impacted cyst production in the basin with a 1-year lag, and may have contributed to the unusually high fluxes of cysts type "Cp" (possibly the cysts of the toxic dinoflagellate Cochlodinium
polykrikoides sensu Li et al., 2015), with cyst type Cp fluxes up to 11.8x1000 cysts m(-2) day(-1) observed during the weak upwelling event of February-May 1999.
Possible trophic interactions between dinoflagellates and other major planktonic
groups are also investigated by comparing the timing and magnitude of cyst production with proxies for phytoplanktonic communities (from photopigment data) and micro- to macrozooplankton abundance indicators (from palynological data) at the site.
This work provides new, detailed insights into the ecology of cyst-producing dinoflagellates and will allow for more detailed interpretations of fossil assemblages extracted from sedimentary records in the basin and elsewhere.
|Summary||(Plain Language Summary, not published)|
This study constitutes a proxy calibration effort for more detailed interpretations of fossil dinoflagellate cyst assemblages recovered from sediments,
by analysing cyst production in the context of the physico-chemical and biological environment, using in situ observations.