Cenozoic Marine Diatom Biostratigraphy and Applications to Paleoclimatology and Paleoceanography

Diatoms, golden brown algae, are present in most aqueous environments. Within the marine environment marine diatoms occupy the photic zone and represent the lowest level of the marine food chain. Diatoms are either planktonic or benthic and possess an external siliceous skeleton or frustule, that is boxlike in structure. The size of diatom frustules ranges from less than 1 μm to more than 1,000 μm, but most frustules range in size from 10 to 100 μm. Diatoms are present in the geological record from at least the Cretaceous (Harwood and Nikolaev, this volume) and have numerous advantages for biostratigraphic correlation and paleoenvironmental reconstruction of marine sedimentary sequences. This chapter summarizes the current state of marine diatom biostratigraphy for the Cenozoic and provides examples of how marine diatoms are used in paleoenvironmental reconstructions. No attempt is made to illustrate the various diatom taxa discussed; the reader is referred to published references such as the syntheses of Fenner (1985) and Barron (1985).

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SMFC as a tool for the removal of hydrocarbons and metals in the marine environment: a concise research update

Environmental Science and Pollution Research ◽

10.1007/s11356-021-13593-3 ◽

2021 ◽

Author(s):

Edvige Gambino ◽

Kuppam Chandrasekhar ◽

Rosa Anna Nastro

Keyword(s):

Marine Environment ◽

Microbial Fuel Cells ◽

Energy Production ◽

Marine Pollution ◽

Future Perspectives ◽

Sediment Remediation ◽

Marine Food Chain ◽

Marine Food ◽

Accumulation Of Pollutants ◽

Insight Into

AbstractMarine pollution is becoming more and more serious, especially in coastal areas. Because of the sequestration and consequent accumulation of pollutants in sediments (mainly organic compounds and heavy metals), marine environment restoration cannot exempt from effective remediation of sediments themselves. It has been well proven that, after entering into the seawater, these pollutants are biotransformed into their metabolites, which may be more toxic than their parent molecules. Based on their bioavailability and toxic nature, these compounds may accumulate into the living cells of marine organisms. Pollutants bioaccumulation and biomagnification along the marine food chain lead to seafood contamination and human health hazards. Nowadays, different technologies are available for sediment remediation, such as physicochemical, biological, and bioelectrochemical processes. This paper gives an overview of the most recent techniques for marine sediment remediation while presenting sediment-based microbial fuel cells (SMFCs). We discuss the issues, the progress, and future perspectives of SMFC application to the removal of hydrocarbons and metals in the marine environment with concurrent energy production. We give an insight into the possible mechanisms leading to sediment remediation, SMFC energy balance, and future exploitation.

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Potential Use of Biomarkers in Zooplankton as Early Warning Signals of Ecotoxicological Risk in the Marine Food Chain

Marine Ecology ◽

10.1111/j.1439-0485.2002.tb00027.x ◽

2002 ◽

Vol 23 (s1) ◽

pp. 291-296 ◽

Cited By ~ 4

Author(s):

Roberta Minutoli ◽

Maria Cristina Fossi ◽

Letterio Guglielmo

Keyword(s):

Food Chain ◽

Early Warning ◽

Warning Signals ◽

Early Warning Signals ◽

Ecotoxicological Risk ◽

Marine Food Chain ◽

Marine Food ◽

Potential Use

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Diatoms as a paleoproductivity proxy in the NW Iberian coastal upwelling system (NE Atlantic)

Biogeosciences ◽

10.5194/bg-14-1165-2017 ◽

2017 ◽

Vol 14 (5) ◽

pp. 1165-1179 ◽

Cited By ~ 8

Author(s):

Diana Zúñiga ◽

Celia Santos ◽

María Froján ◽

Emilia Salgueiro ◽

Marta M. Rufino ◽

...

Keyword(s):

Water Column ◽

Surface Sediment ◽

Sediment Trap ◽

Coastal Upwelling ◽

Late Summer ◽

Early Summer ◽

Marine Diatom ◽

Photic Zone ◽

Upwelling System ◽

Water Column Stratification

Abstract. The objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 (±5.6) 106 valves m−2 d−1) represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom-derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Furthermore, Chaetoceros spp. dominate during spring–early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment's total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes.

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Uptake and trophic changes in polybrominated diphenyl ethers in the benthic marine food chain in southwestern British Columbia, Canada

FACETS ◽

10.1139/facets-2018-0021 ◽

2019 ◽

Vol 4 (1) ◽

pp. 20-51

Author(s):

Brenda Burd ◽

Chris Lowe ◽

Carmen Morales-„Caselles ◽

Marie Noel ◽

Peter Ross ◽

...

Keyword(s):

Organic Carbon ◽

Polybrominated Diphenyl Ethers ◽

Dry Weight ◽

Trophic Levels ◽

Marine Food Chain ◽

Deposit Feeders ◽

Diphenyl Ethers ◽

Bottom Fish ◽

Harbour Sediment ◽

Marine Food

We examined the physical and geochemical effects of sediment on the uptake of polybrominated diphenyl ethers (PBDEs) into marine sediment feeders and their transfer to higher trophic fauna. Sediment PBDEs increased with % total organic carbon (%TOC), organic carbon (OC) flux and grain size (%fines). Tissue PBDE variance was best explained ( R2 = 0.70) by sediment acid volatile sulfides (AVS), PBDEs, and organic lability and input, with the highest values near wastewater outfalls. Dry weight tissue/sediment PBDEs declined with increasing sediment PBDEs, resulting in tissue dilution (ratio <1) at >10 000 pg/g in harbours. Ratios also decreased with increasing %fines, resulting in regional differences. These patterns imply that high levels of fines and high sediment concentrations make PBDEs less bioavailable. Dry weight PBDEs increased >100× between background deposit feeders and predators (polychaetes, crabs, bottom fish, seal), but lipid normalized PBDEs barely increased (<1.3%), suggesting remarkably high uptake in low-lipid sediment feeders, and that PBDEs don’t accumulate at higher trophic levels, but lipid content does. Filter feeders had lower lipid-normalized PBDEs than deposit feeders, highlighting the importance of food resources in higher trophic fauna for bioaccumulation. The most profound congener change occurred with sediment uptake, with nona/deca-BDEs declining and tetra-hexa-BDEs increasing. Harbour sediment feeders had more deca-BDEs than other samples, suggesting PBDEs mostly pass unmodifed through them. Deca-BDEs persist patchily in all tissues, reflecting variable dependence on sediment/pelagic food.

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Mutations in transmembrane proteins: diseases, evolutionary insights, prediction and comparison with globular proteins

Briefings in Bioinformatics ◽

10.1093/bib/bbaa132 ◽

2020 ◽

Author(s):

Jan Zaucha ◽

Michael Heinzinger ◽

A Kulandaisamy ◽

Evans Kataka ◽

Óscar Llorian Salvádor ◽

...

Keyword(s):

Membrane Proteins ◽

Membrane Protein ◽

Lipid Bilayers ◽

Protein Structures ◽

Experimental Studies ◽

Single Amino Acid ◽

Evolutionary Information ◽

Missense Variants ◽

Current State ◽

Aqueous Environments

Abstract Membrane proteins are unique in that they interact with lipid bilayers, making them indispensable for transporting molecules and relaying signals between and across cells. Due to the significance of the protein’s functions, mutations often have profound effects on the fitness of the host. This is apparent both from experimental studies, which implicated numerous missense variants in diseases, as well as from evolutionary signals that allow elucidating the physicochemical constraints that intermembrane and aqueous environments bring. In this review, we report on the current state of knowledge acquired on missense variants (referred to as to single amino acid variants) affecting membrane proteins as well as the insights that can be extrapolated from data already available. This includes an overview of the annotations for membrane protein variants that have been collated within databases dedicated to the topic, bioinformatics approaches that leverage evolutionary information in order to shed light on previously uncharacterized membrane protein structures or interaction interfaces, tools for predicting the effects of mutations tailored specifically towards the characteristics of membrane proteins as well as two clinically relevant case studies explaining the implications of mutated membrane proteins in cancer and cardiomyopathy.

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