scholarly journals Phytoplankton Exopolymers Enhance Adhesion of Microplastic Particles to Submersed Surfaces

2019 ◽  
Vol 23 ◽  
pp. 60-69
Author(s):  
Evgeniy G. Sakhon ◽  
Vladimir S. Mukhanov ◽  
Antonina N. Khanaychenko
Keyword(s):  
Turbulent Mixing ◽  
Marine Phytoplankton ◽  
Marine Environments ◽  
Additional Source ◽  
Marine Food Webs ◽  
Bacterial Consortia ◽  
Vertical Glass ◽  
Marine Food ◽  
Global Biogeochemical Cycles ◽  
Glass Surfaces

Intense pollution of marine environments with plastic waste, including micro- and nanoplastics, is a new and poorly studied threat measured in tens of million tonnes annually. Despite a huge scale of the problem, almost nothing is known about pathways and mechanisms of involvement of micro- and nanoplastics in marine food webs, trophic processes, global biogeochemical cycles. In this study, a hypothesis is considered and experimentally verified about the role exopolymers from marine phytoplankton play in flocculating micro- and nanoplastics and forming their aggregates in marine environments to transfer and deposit them further in bottom sediments. In experiments with non-axenic cultures of the cryptophyte Rhodomonas salina (RHO) and the green alga Tetraselmis suecica (TET) exposed to micro-polystyrene particles (MP, 4.3 μm diam., about 0.4 × 106 particles/ml, 16 mg/L), microalgal exudates were shown to promote MP flocculation and immobilization on vertical glass surfaces. The highest levels of MP were “cleared” from the medium by the TET culture which released more extracellular polysacharides. Hetero-aggregation of MP and algal cells was not observed, probably owing to turbulent mixing and cell motility. Abundant bacterial consortia relealed in the cultures (up to 9 × 106 cells ml-1) could be an additional source of exopolymers and serve an agent of MP flocculation and adhesion. Thus, the results obtained highlight the potential for phytoplankton exudates to interact with micro- and nanoplastics, and potentially affect their bioavailability and vertical transport in marine environments.

scholarly journals Phytoplankton adapt to changing ocean environments

2015 ◽  
Vol 112 (18) ◽  
pp. 5762-5766 ◽  
Author(s):  
Andrew J. Irwin ◽  
Zoe V. Finkel ◽  
Frank E. Müller-Karger ◽  
Luis Troccoli Ghinaglia
Keyword(s):  
Climate Change ◽  
Dominant Species ◽  
Phytoplankton Community ◽  
Marine Phytoplankton ◽  
Ecosystem Models ◽  
Environmental Preferences ◽  
Marine Food Webs ◽  
Phytoplankton Communities ◽  
Marine Food ◽  
Carbon Retention

Model projections indicate that climate change may dramatically restructure phytoplankton communities, with cascading consequences for marine food webs. It is currently not known whether evolutionary change is likely to be able to keep pace with the rate of climate change. For simplicity, and in the absence of evidence to the contrary, most model projections assume species have fixed environmental preferences and will not adapt to changing environmental conditions on the century scale. Using 15 y of observations from Station CARIACO (Carbon Retention in a Colored Ocean), we show that most of the dominant species from a marine phytoplankton community were able to adapt their realized niches to track average increases in water temperature and irradiance, but the majority of species exhibited a fixed niche for nitrate. We do not know the extent of this adaptive capacity, so we cannot conclude that phytoplankton will be able to adapt to the changes anticipated over the next century, but community ecosystem models can no longer assume that phytoplankton cannot adapt.

scholarly journals Dynamics and functional diversity of the smallest phytoplankton on the Northeast US Shelf

2020 ◽  
Vol 117 (22) ◽  
pp. 12215-12221 ◽  
Author(s):  
Bethany L. Fowler ◽  
Michael G. Neubert ◽  
Kristen R. Hunter-Cevera ◽  
Robert J. Olson ◽  
Alexi Shalapyonok ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Viral Lysis ◽  
Structured Population Model ◽  
Marine Food Webs ◽  
Structured Population ◽  
Marine Food ◽  
Global Biogeochemical Cycles ◽  
Northeast Us ◽  
Long Timescales

Picophytoplankton are the most abundant primary producers in the ocean. Knowledge of their community dynamics is key to understanding their role in marine food webs and global biogeochemical cycles. To this end, we analyzed a 16-y time series of observations of a phytoplankton community at a nearshore site on the Northeast US Shelf. We used a size-structured population model to estimate in situ division rates for the picoeukaryote assemblage and compared the dynamics with those of the picocyanobacteriaSynechococcusat the same location. We found that the picoeukaryotes divide at roughly twice the rate of the more abundantSynechococcusand are subject to greater loss rates (likely from viral lysis and zooplankton grazing). We describe the dynamics of these groups across short and long timescales and conclude that, despite their taxonomic differences, their populations respond similarly to changes in the biotic and abiotic environment. Both groups appear to be temperature limited in the spring and light limited in the fall and to experience greater mortality during the day than at night. Compared withSynechococcus, the picoeukaryotes are subject to greater top-down control and contribute more to the region’s primary productivity than their standing stocks suggest.

scholarly journals Exploration of marine phytoplankton: from their historical appreciation to the omics era

2020 ◽  
Author(s):  
Juan Jose Pierella Karlusich ◽  
Federico M Ibarbalz ◽  
Chris Bowler
Keyword(s):  
Large Scale ◽  
18Th Century ◽  
Net Primary Production ◽  
Marine Phytoplankton ◽  
Earth System ◽  
Marine Food Webs ◽  
Biological Oceanography ◽  
Initial Identification ◽  
Marine Food ◽  
Biological Component

Abstract Marine phytoplankton are believed to account for more than 45% of photosynthetic net primary production on Earth, and hence are at the base of marine food webs and have an enormous impact on the entire Earth system. Their members are found across many of the major clades of the tree of life, including bacteria (cyanobacteria) and multiple eukaryotic lineages that acquired photosynthesis through the process of endosymbiosis. Our understanding of their distribution in marine ecosystems and their contribution to biogeochemical cycles have increased since they were first described in the 18th century. Here, we review historical milestones in marine phytoplankton research and how their roles were gradually understood, with a particular focus on insights derived from large-scale ocean exploration. We start from the first observations made by explorers and naturalists, review the initial identification of the main phytoplankton groups and the appreciation of their function in the influential Kiel and Plymouth schools that established biological oceanography, to finally outline the contribution of modern large-scale initiatives to understand this fundamental biological component of the ocean.

Stable nitrogen and carbon isotopes in sediments and biota from three tropical marine food webs: Application to chemical bioaccumulation assessment

2017 ◽  
Vol 36 (9) ◽  
pp. 2521-2532 ◽  
Author(s):  
Hui Zhang ◽  
Yun Teng ◽  
Tra Thi Thanh Doan ◽  
Yun Wei Yat ◽  
Sheot Harn Chan ◽  
...  
Keyword(s):  
Food Webs ◽  
Carbon Isotopes ◽  
Marine Food Webs ◽  
Marine Food

scholarly journals Krill: a potential vector for domoic acid in marine food webs

2002 ◽  
Vol 237 ◽  
pp. 209-216 ◽  
Author(s):  
S Bargu ◽  
CL Powell ◽  
SL Coale ◽  
M Busman ◽  
GJ Doucette ◽  
...  
Keyword(s):  
Food Webs ◽  
Domoic Acid ◽  
Potential Vector ◽  
Marine Food Webs ◽  
Marine Food

Feeding habits and trophic level of the smooth hammerhead shark, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), off Ecuador

2018 ◽  
Vol 99 (3) ◽  
pp. 673-680 ◽  
Author(s):  
Colombo Estupiñán-Montaño ◽  
Luis Cedeño-Figueroa ◽  
José F. Estupiñán-Ortiz ◽  
Felipe Galván-Magaña ◽  
Alejandro Sandoval-Londoño ◽  
...  
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Trophic Niche ◽  
Commercial Fishing ◽  
Dosidicus Gigas ◽  
Apex Predators ◽  
Marine Food Webs ◽  
Fishing Vessels ◽  
Marine Food ◽  
Index Of Relative Importance

As apex predators, sharks are known to play an important role in marine food webs. Detailed information on their diet and trophic level is however needed to make clear inferences about their role in the ecosystem. A total of 335 stomachs of smooth hammerhead sharks, Sphyrna zygaena, were obtained from commercial fishing vessels operating in the Ecuadorian Pacific between January and December 2004. A total of 53 prey items were found in the stomachs. According to the Index of Relative Importance (%IRI), cephalopods were the main prey (Dosidicus gigas, Sthenoteuthis oualaniensis, Ancistrocheirus lesueurii and Lolliguncula [Loliolopsis] diomedeae). Sphyrna zygaena was thus confirmed to be a teutophagous species. The estimated trophic level of S. zygaena was between 4.6 and 5.1 (mean ± SD: 4.7 ± 0.16; males: 4.7; females: 4.8). Levin's index (BA) was low (overall: 0.07; males: 0.08; females: 0.09), indicating a narrow trophic niche. We found that sharks <150 cm in total length consumed prey of coastal origin, whereas sharks ≥150 cm foraged in oceanic waters and near the continental shelf. The analyses indicate that S. zygaena is a specialized predator consuming mainly squids.

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