The abundances and mass accumulation rates of biomarkers indicate that phytoplankton productivity was relatively higher during glacial periods than during interglacial periods. View full-textĪ high-resolution molecular organic geochemical study of core MD05-2904 reveals changes in the productivity and community structure of paleo-phytoplankton during the last 260 ka in the northern South China Sea (SCS).Multiple biomarkers, including C37 alkenones, dinosterol, brassicasterol and C30 diols, are used as representatives of haptophytes, dinoflagellates, diatoms and eustigmatophytes. Both red algae stimulated the growth of Ostreopsis ovata to a similar degree. Growth was also slightly stimulated by the brown algae Turbinaria ornata and Sargassum cf. toxicus, while Portieria hornemanii stimulated it. The red alga, Halymenia floresia (Cryptonemiaceae), inhibited growth of G.

Experimental bio-assays to compare growth in seawatcrs previously incubated with macroalgae, showed pre-conditioned seawaters could be either stimulatory or inhibitory. On macroalgal substrates, dinoflagellates were moderately abundant, but some substrates, such as several red algae, supported higher abundances suggesting a stimulation. toxicus, occurred on dead corals, more especially on the inner slope of the barrier reef and on lagoonal patch-reefs, but not at the back of the bay nor on the barrier reef outer slope. Highest abundances of all species of dinoflagellales, particularly G. and Prorocentrum spp., generally exhibited the following relative abundances: Ostreopsis spp. On nearly all the substrates, the dinoflagellates Gambierdiscus toxicus Adachi and Fukuyo, Ostreopsis spp.

through lagoonal patch-reefs, and a second area comprised a lagoonal complex. One area consisted of a transect between an alluvial coastal bay and the outer barrier reef. Different substrates were investigated (algae, algal turfs and dead corals) in two areas. Both oceanic and lagoonal waters were oligotrophic. The spatial distribution of ciguateric dinoflagellates was investigated in the coral reef lagoon of the island of Mayotte at the end of the dry season of 1992. The establishment of the modern-type marine protist world was concluded in the late Eocene by the appearance of collodarians, the continuous occurrences of ebridians, and the substituted silicon precipitation marine protists as diatoms. After the initial appearance period, the emergence of fossilizable skeleton formative ability was concentrated in five short geological time intervals: (1) the Middle to Late Devonian for calcareous benthic foraminifers (2) the Carnian to the Rhaetian (Triassic) for the “switching on” of fossilizable dinoflagellate cysts, nannoliths, coccoliths and calcareous cysts, and probably the molecular appearance of diatoms (3) the Toarcian–Aalenian Ages for diversified dinoflagellates and coccolithophores, the establishment of symbiosis in radiolarian Acantharia and the appearance of planktic lifestyle in foraminifers (4) the Albian–Maastrichtian Ages for the rapid accumulation of coccolithophores, the start of skeletogenesis both in silicoflagellates and marine centric diatoms, molecular appearance of both araphid and raphid diatoms, and the appearance of fossilizable araphid diatoms and (5) the middle to late Eocene for the appearance of fossilizable raphid diatoms and radiolarian colonial collodarians and the continuous occurrences of ebridians.

fossilizable radiolarian polycystine is likely to have appeared in the period of the Cambrian Explosion.

Multichambered foraminifers appeared around the start of biomineralization in Small Shelly Fossils in the early Cambrian. The probable heterotrophic agglutinated microfossil appeared when marine metazoans appeared in the Ediacaran. The oldest marine protist fossil goes back 1.8 Ga (Statherian, Paleoproterozoic), and the oldest dinosterane biomarkers 1.6 Ga (Calymmian, Mesoproterozoic).

Jellyfissh plankton nekton or benthos