Publikationsdatum:
2024-02-02
Beschreibung:
Flux of bulk components, carbonate- and silicate-bearing skeleton organisms, and the d15N-isotopic signal were investigated on a 1-year time-series sediment trap deployed at the pelagic NU mooring site (Namibia Upwelling, ca. 29°S, 13°E) in the central Benguela System. The flux of bulk components mostly shows bimodal seasonality with major peaks in austral summer and winter, and moderate to low export in austral fall and spring. The calcium carbonate fraction dominates the export of particulates throughout the year, followed by lithogenic and biogenic opal. Planktonic foraminifera and coccolithophorids are major components of the carbonate fraction, while diatoms clearly dominate the biogenic opal fraction. Bulk d15N isotopic composition of particulate matter is positively correlated with the total mass flux during summer and fall, while negatively correlated during winter and spring. Seasonal changes in the intensity of the main oceanographic processes affecting the NU site are inferred from variations in bulk component flux, and in the flux and diversity patterns of individual species or group of species. Influence from the Namaqua (Hondeklip) upwelling cell through offshore migration of chlorophyll filaments is stronger in summer, while the winter flux maximum seems to reflect mainly in situ production, with less influence from the coastal and shelf upwelling areas. On a yearly basis, dominant microorganisms correspond well with the flora and fauna of tropical/subtropical waters, with minor contribution of near-shore organisms. The simultaneous occurrence of species with different ecological affinities mirrors the fact that the mooring site was located in a transitional region with large hydrographic variability over short-time intervals.
Schlagwort(e):
Actinocyclus curvatulus; Actinocyclus curvatulus, flux; Actinocyclus octonarius; Actinocyclus octonarius, flux; Azpeitia spp.; Azpeitia spp., flux; Calcidiscus leptoporus; Calcidiscus leptoporus, flux; Calcium carbonate, flux; Calcium carbonate, flux of total flux; Calculated; Calculated, see reference(s); Carbon, organic, particulate, flux; Carbon, organic, particulate, flux of total flux; Center for Marine Environmental Sciences; Coccolith, fluxes; Coccospheres, flux; Coscinodiscus radiatus; Coscinodiscus radiatus, flux; DATE/TIME; Date/time end; DEPTH, water; Diatom valves, flux; Duration, number of days; Element analyser CHN, Heraeus; Elphidium advenum; Emiliania huxleyi; Emiliania huxleyi, flux; Foraminifera, planktic, flux; Fragilariopsis doliolus; Fragilariopsis doliolus, flux; Gladiolithus flabellatus; Gladiolithus flabellatus, flux; Globigerina bulloides; Globigerina bulloides, flux; Globigerinoides ruber white; Globigerinoides ruber white, flux; Globorotalia inflata; Globorotalia inflata, flux; Lithogenic, flux; Lithogenic, flux of total flux; M20/2; MARUM; Mass spectrometer Finnigan Delta Plus; Meteor (1986); Namibia upwelling, Southeast Atlantic; Neogloboquadrina pachyderma dextral; Neogloboquadrina pachyderma dextral, flux; NU; NU2_trap; Oolithotus fragilis; Oolithotus fragilis, flux; Opal, auto analysis (Müller & Schneider, 1993); Opal, flux; Opal, flux of total flux; Orbulina universa; Orbulina universa, flux; Sample code/label; Syracosphaera lamina; Syracosphaera lamina, flux; Thalassionema nitzschioides, flux; Thalassionema nitzschioides var. inflata; Total mass, flux per day; Trap, sediment; TRAPS; δ15N, gas
Materialart:
Dataset
Format:
text/tab-separated-values, 1100 data points
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