Eutrophication of Estuarine and Coastal Ecosystems

Rabalais, Nancy N.

doi:10.1002/9780470495117.ch5

Cited by 14 publications

(14 citation statements)

References 77 publications

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“…We conducted a series of in situ experiments in the Northern Adriatic (Mediterranean Sea), one of the areas repeatedly affected by seasonal hypoxia (Barmawidjaja et al, 1995;Rabalais, 2010;Giani et al, 2012). They were designed to better understand how anoxia affects benthic macrofauna and meiofauna survival and how fast the impacted zone attains a new ecological equilibrium.…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Artificially induced migration of redox layers in a coastal sediment from the Northern Adriatic

et al. 2014

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Abstract. Long-term experimental studies suggest that, under transient anoxic conditions, redox fronts within the sediment shift upwards, causing sequential rise and fall of benthic fluxes of reduced species (Mn(II), Fe(II) and S(-II)). Infaunal benthic organisms are associated with different redox fronts as micro-habitats and must be affected by such changes during natural hypoxia events. In order to document the geochemical evolution of the sediment during prolonged anoxia in the framework of an in situ experiment designed to mimic natural conditions, benthic chambers were deployed on the seafloor of the Northern Adriatic and sampled after 9, 30 and 315 days of incubation. Oxygen and sulfide were measured continuously in the early stages (9 days) of the experiment. High-resolution pore water profiles were sampled by DET probes and redox-sensitive species (S(VI), Mn(II) and Fe(II)) and alkalinity were measured.Starting oxygen saturation was about 80 % within the chamber. After 7 days, anoxia was established in the bottom waters within the chambers. Mn(II) and Fe(II) started diffusing towards the anoxic water column until they reached the surficial sediment. Being reoxidized there, Mn and Fe reprecipitated, giving a rusty coloration to the seafloor. Infaunal species appeared at the sediment surface. After 20 days, all macro-organisms were dead. Decomposition of macroorganisms at the sediment-water interface generated S(-II) within the entire height of the chamber, leading to a downward flux of sulfides into the sediment, where they were quickly oxidized by metallic oxides or precipitated as FeS. S(-II) was below detection in the water column and pore waters at the end of the experiment. Our results suggest that S(-II) enrichment in the water column of coastal systems, which are episodically anoxic, is strongly controlled by the biomass of benthic macrofauna and its decay during anoxia, whereas its residence time in the water column is controlled by iron availability (as solid oxides or as dissolved reduced cations) within the sediment, even without water circulation.

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Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Artificially induced migration of redox layers in a coastal sediment from the Northern Adriatic

et al. 2014

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“…Continental discharge is one of the main sources of terrigenous sediments, nutrients, and anthropogenic pollution in the sea and can significantly affect seabed morphology, water quality, primary productivity, and fishery in coastal areas (e.g., Emmet, 2006;Milliman et al, 2007;Zhou et al, 2008;Rabalais, 2010). Generally, the majority of fluvial runoff and the related discharge of its suspended and dissolved constituents on a regional scale are provided by the largest local rivers, and small rivers (i.e., rivers with small drainage basins and small annual discharges) usually play an insignificant role.…”

Section: Introductionmentioning

confidence: 99%

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

Osadchiev

Korshenko

2017

Ocean Sci.

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Abstract. This study focuses on the impact of discharges of small rivers on the delivery and fate of fluvial water and suspended matter at the northeastern part of the Black Sea under different local precipitation conditions. Several dozens of mountainous rivers flow into the sea at the study region, and most of them, except for several of the largest, have little annual runoff and affect adjacent coastal waters to a limited extent under average climatic conditions. However, the discharges of these small rivers are characterized by a quick response to precipitation events and can significantly increase during and shortly after heavy rains, which are frequent in the considered area. The delivery and fate of fluvial water and terrigenous sediments at the study region, under average climatic and rain-induced flooding conditions, were explored and compared using in situ data, satellite imagery, and numerical modeling. It was shown that the point-source spread of continental discharge dominated by several large rivers under average climatic conditions can change to the linesource discharge from numerous small rivers situated along the coast in response to heavy rains. The intense line-source runoff of water and suspended sediments forms a geostrophic alongshore current of turbid and freshened water, which induces the intense transport of suspended and dissolved constituents discharged with river waters in a northwestern direction. This process significantly influences water quality and causes active sediment load at large segments of the narrow shelf at the northeastern part of the Black Sea compared to average climatic discharge conditions.

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“…These include but are not restricted to habitat loss and/or modification, excessive harvesting of wild seed/spawners, introduction of exotic species, unintended release of cultured animals, spread of diseases, deleterious interactions with wild populations, misuse of chemicals and antibiotics, and release of wastes [1,[111][112][113]. The release of wastes is perhaps one of the most relevant impacts affecting coastal ecosystems.…”

Section: Eps-based Flocculation With Potential In Waste Treatment Promentioning

confidence: 99%

Implications of Extracellular Polymeric Substance Matrices of Microbial Habitats Associated with Coastal Aquaculture Systems

Camacho-Chab

Lango-Reynoso

Castañeda-Chávez

et al. 2016

Water

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Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS) synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured species, removing waste and contributing to the hygiene of closed systems. As ubiquitous components of coastal microbial habitats at the air-seawater and seawater-sediment interfaces as well as of biofilms and microbial aggregates, EPS mediate deleterious processes that affect the performance and productivity of aquaculture facilities, including biofouling of marine cages, bioaccumulation and transport of pollutants. These biomolecules may also contribute to the persistence of harmful algal blooms (HABs) and their impact on cultured species. EPS may also exert a positive influence on aquaculture activity by enhancing the settling of aquaculturally valuable larvae and treating wastes in bioflocculation processes. EPS display properties that may have biotechnological applications in the aquaculture industry as antiviral agents and immunostimulants and as a novel source of antifouling bioproducts.

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Eutrophication of Estuarine and Coastal Ecosystems

Cited by 14 publications

References 77 publications

Artificially induced migration of redox layers in a coastal sediment from the Northern Adriatic

Artificially induced migration of redox layers in a coastal sediment from the Northern Adriatic

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

Implications of Extracellular Polymeric Substance Matrices of Microbial Habitats Associated with Coastal Aquaculture Systems

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