Distribution of organic-walled dinoflagellate cysts in surface sediments of the southern Caribbean and the eastern tropical Pacific and its environmental implications

Ramírez-Valencia, Valentina; Paez-Reyes, Manuel; Salgado, Jorge; Sangiorgi, Francesca; Zúñiga-González, Andrés Camilo; Amézquita, Adolfo; Ibarra‐Avila, Humberto; González‐Arango, Catalina

doi:10.1016/j.marmicro.2021.102000

Cited by 6 publications

(3 citation statements)

References 105 publications

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“…Besides a high H /A ratio on the nutrient-rich Louisiana shelf, the H /A ratio is also high on the western shelf, where net primary productivity is lower. Similarly high H /A ratios have also been found in different dinocyst assemblages from areas with varying nutrient levels, indicating that using the H /A ratio as a sole proxy can be misleading (Ramírez-Valencia et al, 2021). Also, in regions with varying oxygen levels, the use of relative abundances of heterotrophs may be influenced by the differential preservation potential for autotrophic and heterotrophic dinocysts (Zonneveld et al, 2001(Zonneveld et al, , 2008(Zonneveld et al, , 2010Gray et al, 2017).…”

Section: Palynology As An Indicator For Marine Productivitymentioning

confidence: 98%

“…Absolute dinocyst concentrations and fluxes are less affected by oxygen levels and potential preservation biases between autotrophic and heterotrophic dinocysts and could therefore provide a clearer link with primary production (Zonneveld et al, 2009). Indeed, dinocyst concentrations have been linked to high nutrient levels and eutrophication in estuaries and coastal waters (Radi et al, 2007;Dale, 2009;Zonneveld et al, 2009), although this correlation is not always found (de Vernal et al, 2020). In the GoM, the highest dinocyst concentrations occur on the shelf between the MR and AR mouths, concurrent with the highest H /A ratio (Fig.…”

Section: Palynology As An Indicator For Marine Productivitymentioning

confidence: 99%

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Dinoflagellate cyst and pollen assemblages as tracers for marine productivity and river input in the northern Gulf of Mexico

Yedema,

Donders,

Peterse

et al. 2023

J. Micropalaeontol.

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Abstract. Both marine dinoflagellate cysts and terrestrially derived pollen and spores are abundant in coastal sediments close to river mouths, making sediment records from such settings ideal to simultaneously study land–ocean climate interactions, marine productivity patterns and freshwater input over time. However, few studies consider the combined calibration of these palynological proxies in modern coastal sediments offshore from rivers, which is needed to strengthen the interpretation of paleoreconstructions. Here, we analyze the palynological content of marine surface sediments along land–sea transects off the Mississippi and Atchafalaya river mouths in the northern Gulf of Mexico (GoM) and test three palynological indices which are often employed in the paleo-domain: (i) the abundance of cysts of heterotrophic and autotrophic dinoflagellates (dinocysts) as a tracer for primary productivity (H/A ratio) and (ii) the ratio between non-bisaccate pollen and bisaccates (P/B) as well as (iii) the ratio between pollen (excluding bisaccates) and dinocysts (P/D), which are both tracers for river input and distance to the coast. Our results show that dinoflagellate cysts are most abundant on the shelf, where heterotrophic dinocyst species dominate coastal assemblages in reach of the river plume, while autotrophic taxa are more present in the oligotrophic open ocean. This is clearly reflected in decreasing H/A values further offshore. Individual dinocyst taxa also seem to inhabit specific niches along an onshore–offshore transect, linked to nutrient availability and proximity to the turbid river plume. The highest pollen concentrations are found close to the Mississippi river mouth and mostly represent a mixture of local coastal and upstream vegetation, whereas bisaccate pollen was most abundant further offshore of the Mississippi river. Multivariate redundancy analysis (RDA) performed on both pollen and dinocyst assemblages, a set of environmental parameters, and the three palynological ratios showed that net primary productivity was the most important variable influencing the dinocyst assemblages, likely as the result of nutrient input. Additionally, the RDA confirmed that the H/A ratio indeed seems to track primary productivity, while the P/B ratio results in a robust indicator for distance to the coast, and the P/D ratio better reflects river input. Together, our data confirm and further specify the suitability of these three palynological ratios in river-dominated coastal margins as proxies for (past) marine productivity and distance to the coast and river.

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Section: Palynology As An Indicator For Marine Productivitymentioning

confidence: 98%

Section: Palynology As An Indicator For Marine Productivitymentioning

confidence: 99%

Dinoflagellate cyst and pollen assemblages as tracers for marine productivity and river input in the northern Gulf of Mexico

Yedema,

Donders,

Peterse

et al. 2023

J. Micropalaeontol.

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“…Nitrogen and phosphorus biogeochemical cycles are completely disrupted, and current levels in the Magdalena exceed pre-1950 levels by one order of magnitude (Restrepo 2008). This nutrient excess affects many biological processes in riverine, terrestrial, and marine ecosystems (e.g., Ramírez-Valencia et al 2021). Catchment urbanization across the Magdalena River basin is also expanding rapidly.…”

Section: Water Pollution and Urbanizationmentioning

confidence: 99%

Causes and consequences of recent degradation of the Magdalena River basin, Colombia

Salgado

Shurin

Vélez

et al. 2022

Limnol Oceanogr Letters

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Large tropical rivers provide essential societal benefits, including food production, irrigation, hydropower, transportation, and trade routes. However, these human activities pose unprecedented challenges to the integrity of the river systems, a problem that, in most cases, occurs without fully understanding the natural dynamics of these valuable ecosystems. Here, we synthesize the status of recent and long-term (decades-centuries) anthropogenic impacts occurring in one of the world's hotspots of tropical fish diversity, the Magdalena River, Colombia. Unfortunately, the Magdalena River has attracted little research attention compared to similar tropical rivers. We seek to promote research on the compounding impacts of climate change, river impoundment, alien invasive species, catchment deforestation, and water pollution on the Magdalena and the ecosystem services it provides.

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Palynostratigraphy indication of the Pliocene–Pleistocene boundary in Hupo Basin of the East Sea, offshore Korea

Hong

Yoo

et al. 2022

Mar Geophys Res

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Distribution of organic-walled dinoflagellate cysts in surface sediments of the southern Caribbean and the eastern tropical Pacific and its environmental implications

Cited by 6 publications

References 105 publications

Dinoflagellate cyst and pollen assemblages as tracers for marine productivity and river input in the northern Gulf of Mexico

Dinoflagellate cyst and pollen assemblages as tracers for marine productivity and river input in the northern Gulf of Mexico

Causes and consequences of recent degradation of the Magdalena River basin, Colombia

Palynostratigraphy indication of the Pliocene–Pleistocene boundary in Hupo Basin of the East Sea, offshore Korea

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