Marine Palynomorphs Dominated by Heterotrophic Organism Remains in the Tropical Coastal Shallow-Water Sediment; the Case of Selangor Coast and the Estuary of the Manjung River in Malaysia

Palynomorph Assemblages Dominated by Heterotrophic Marine Palynomorphs in Tropical Coastal Shallow-water Sediments from the Southern Myanmar Coast

“…However, when the sedimentation rate is the primary driver, it is difficult to determine why the tropical shallow-water dinoflagellate cyst assemblage differs from that of temperate areas. Indeed, Matsuoka et al (2017) suggested another factor of less light penetration relative to water column irradiance during the rainy season. Such attenuation of light due to rich suspended particles caused a low cell number of photosynthetic plankton, including cyst-forming dinoflagellates in tropical coastal areas.…”

“…These remains consist of different groups of planktonic and benthic microorganisms, such as the resting cysts of dinoflagellates, resting cysts and lorica of tintinids (tintinomorphs), organic linings of smaller benthic foraminifers (microforaminiferal linings), appendages, body and resting eggs of crustanceans (mainly copepods), and micro-remains of unknown organisms called acritarchs (Matsuoka et al 2017). These organic-walled micro-remains preserved in sediments are regarded as a useful proxy of coastal environments and used in reconstructing coastal marine environmental history.…”

“…JARQ 52 (1) 2018 K. Matsuoka et al Selangor in Malaysia (Matsuoka et al 2017). These studies concluded that the densities of dinoflagellate cysts preserved in surface sediments were lower in tropical regions than in temperate or sub-boreal regions (Furio et al 2006(Furio et al , 2012.…”

“…In addition, Baula et al (2011) suggested that lower cyst density was due to high sedimentation rates accompanied by high precipitation and high fluvial sediment loads. Matsuoka et al (2017) carefully observed the residues of sediments collected from the Selangor region of Malaysia and from Oman after palynological processing, and found that not only dinoflagellate cysts but also other palynomorphs such as tintinnomorphs, microforaminiferal linings, copepod eggs, bodies and appendages, scolecodonts and butterfly scales were preserved in these tropical surface sediments. Matsuoka et al (2017) also found a relatively high proportion of heterotrophic dinoflagellate cysts and abundant occurrences of microforaminiferal linings, albeit with low photosynthetic dinoflagellate cysts.…”

“…Matsuoka et al (2017) carefully observed the residues of sediments collected from the Selangor region of Malaysia and from Oman after palynological processing, and found that not only dinoflagellate cysts but also other palynomorphs such as tintinnomorphs, microforaminiferal linings, copepod eggs, bodies and appendages, scolecodonts and butterfly scales were preserved in these tropical surface sediments. Matsuoka et al (2017) also found a relatively high proportion of heterotrophic dinoflagellate cysts and abundant occurrences of microforaminiferal linings, albeit with low photosynthetic dinoflagellate cysts. These findings were also supported by Su-Myat et al (2012) as they reported relatively low cyst densities of modern dinoflagellates along the coast of Kadan Island in southern Myanmar, and by our subsequent study in the same areas that found an extreme abundance of microforaminiferal linings.…”