Academic literature on the topic 'Mussel farm biodeposition'

The role of mussels in formation of water chemical composition is determined by the peculiarities of sorption and trophodynamic processes. Copper is a vital element, but of ten metals the toxic effect of which was tested for the survival of mussel and oyster embryos, copper is following mercury. Studying the regularities of copper content change during mussel ontogeny allows to determine both sanitary and hygienic risks of mussel product use during the mollusks cultivation in mariculture and the biogeochemical role in the formation of the chemical composition of the marine water near mussel farms. The purpose of this work is to determine the copper content in the organs and tissues of the mussels during seasonal course of mollusks ontogenesis, to analyze the degree of copper assimilation along the food path of mineral nutrition using the mathematical model and empirical data and to assess the influence of marine farms on the copper exchange processes in the coastal ecosystem. The mollusks were collected from the mussel farm located in the external roadstead of Sevastopol. Studying the copper content in the environment – mussel – biodeposition system, a method of atomic absorption spectroscopy with electrothermal atomization was used. A general model illustrating the process of copper exchange between the mussels and the water environment is presented. Equations for determining the degree of assimilation of metal from food (q) and the limiting coefficient of food accumulation of metal (Кп) are proposed based on the results of measurements of its concentrations in the mussels’ diet, soft tissue and their biodeposition without using radioactive trace elements. The values of the copper removal by the mussel farm were calculated. The role of cultivated mollusks in the heavy metals precipitation was shown.

AbstractMussel aquaculture activities in coastal areas are growing rapidly throughout the world, inducing an increasing interest and concern for their potential impact on coastal marine environments. We have investigated the impact of organic loads due to the biodeposition of a mussel farm in a lagoonar ecosystem of the Mediterranean Sea (Bizerta lagoon, northern Tunisia) on the benthic environment. The most evident changes in the benthic habitat under the farm were a strong reduction of oxygen penetration into the bottom sediments and a large accumulation of chlorophyll a (concentrations up to 16 μg g–1), phaeopigments (concentrations up to 48 μg g–1) and total organic matter (concentrations up to 12%). Results from univariate analysis of the nematofaunal data show that the nematode abundance increased in all the stations located inside the mussel farm (I1, I2, I3) and the site I2, located in the centre of the mussel farm, was the most affected. At this site, Shannon-Wiener index H′, species richness (d), evenness (J′) and number of species (S) decreased significantly. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the organic matter enrichment were varied: Mesacanthion diplechma was eliminated at the most affected station (I2), whereas the abundances of Paracomesoma dubium, Terschellingia longicaudata and T. communis were significantly enhanced. Responses of free-living nematodes to mussel farm biodeposition (elimination of some species and increase or decrease of some others) could lead to food limitation for their predators that, ultimately, could alter entire communities and ecosystems. Consequently, we suggest that site-specific hydrodynamic and biogeochemical conditions should be taken into account when planning new mussel farms, and meiobenthic communities should be monitored before and after farm development to prevent excessive modifications of benthic assemblage structure.

Marine bivalves have been designated ecosystem engineers owing to their capacity to control estuarine water quality, particle dynamics, and primary production. Globally, bivalves have higher production than any other cultured animal. Large populations of natural, invasive, and cultured bivalves are suggested to cause changes in coastal ecosystem function through suspension-feeding of particles and biodeposition of waste materials. Association of bivalves with particle depletion is a trophic tenet of coastal ecosystems, but there are no previous observations of this process except at small scales. Using airborne hyperspectral remote sensing, we show direct evidence of aquaculture impacts at the ecosystem scale (kilometres), documenting significant depletion of phytoplankton through a blue mussel (Mytilus edulis) farm in eastern Canada, compared with dispersion in circulation model results without mussels. Understanding of factors controlling primary production and ecosystem processes in the coastal zone is critical in light of growing reliance on this region for development and resource extraction worldwide.

Marine farms in Peter the Great Bay are oriented predominantly to cultivation of bivalve mollusks that causes excessive accumulation of biodeposits in the areas of plantations. To reduce this negative impact on the ecosystem, development of bicultural farms with cultivation of flterfeeders and detritivores is recommended. In the area of mussel (Mytilus trossulus) plantations in the Sukhodol Bay, the sedimentation rate reaches 34.1 g.m–2.day–1, with mean portion of organic carbon in the biodeposits as 20.2 %. Annual biodeposition from 1 hectare of mussel plantations is about 124 t that corresponds to annual consumption of detritus by 1 million of 1-year-old sea cucumberApostichopus japonicus. By the end of the 4-year cycle of cultivation, the sea cucumbers of commercial size consume this amount of biodeposits within a month (60 g of organic carbon per year each). Production of a sea cucumber plantation with 5 million juveniles of sea cucumber settling every year can exceed 700 t in 10 years of operation, if it is mounted within the bicultural marine farm with bivalve cages as additional source of suspended organic matter.

We evaluate suggestions to harness the ability of calcifying organisms (molluscs, crustacea, corals and coccolithophore algae) to remove permanently CO2 from the atmosphere into solid (crystalline) CaCO3 for atmosphere remediation. Here, we compare this blue carbon with artificial/industrial Carbon dioxide Capture & Storage (CCS) solutions. An industrial CCS facility delivers, at some cost, captured CO2, nothing more. But aquaculture enterprises cultivating shell to capture and store atmospheric CO2 also produce nutritious food and perform many ecosystem services like water filtration, biodeposition, denitrification, reef building, enhanced biodiversity, shoreline stabilisation and wave management. We estimate that a mussel farm sequesters three times as much carbon as terrestrial ecosystems retain. Blue carbon farming does not need irrigation or fertiliser, nor conflict with the use of scarce agricultural land. Blue carbon farming can be combined with restoration and conservation of overfished fisheries and usually involves so little intervention that there is no inevitable conflict with other activities. We calculate that this paradigm shift (from ‘shellfish as food’ to ‘shellfish for carbon sequestration’) makes bivalve mollusc farming and microalgal farming enterprises, viable, profitable, and sustainable, alternatives to all CCUS industrial technologies and terrestrial biotechnologies in use today.

Offshore wind farms (OWFs) are an important source of renewable energy accounting for 2.3% of the European Union's electricity demand. Yet their impact on the environment needs to be assessed. Here, we couple a hydrodynamic (including tides and waves) and sediment transport model with a description of the organic carbon and mineral particle dynamics in the water column and sediments. The model is applied to the Belgian Coastal Zone (BCZ) where OWFs currently occupy 7% of its surface area which is estimated to double in the next 5 years. The impact of OWFs on the environment is represented through the filtration of the water column and fecal pellets production by the blue mussel, the dominant fouling organism. Our model simulations show that the impact of biodeposition on the mud particle sedimentation and on sediment composition is small compared to the fluxes associated with tidal deposition and resuspension and the lateral inputs. In contrast, the total organic carbon (TOC) flux to the sediment is significantly altered inside the OWF perimeters and TOC deposition is increased up to 50% in an area 5 km around the monopiles. Further away, the TOC flux to the bottom decreases with a notable effect up to 30 km away. The major changes are found along the direction of the main residual current and tidal ellipse's major axis. In addition, sub-mesoscale gyres act as retention areas with increased carbon deposition. A future OWF in the BCZ will be located close to gravel beds in a Natura 2000 area, considered as vulnerable habitats and biodiversity hotspots. The different scenarios for this OWF, varying in turbine number and positioning, are compared in terms of impact on the carbon and mineral particle deposition flux in the BCZ and, particularly, to these gravel beds. The scenarios show that the number of turbines has only a slight impact on the TOC deposition flux, unlike their positioning that significantly alters the TOC flux to the gravel beds. The TOC deposition flux exceeds 50%, when the turbines are placed next to the gravel beds; while a limited increase is simulated, when the turbines are located the farthest possible from them.

2011/2012
Molte attività antropiche sono localizzate lungo le coste e poggiano sui molteplici servizi offerti da questi particolari ecosistemi. Con l’aumentare della vulnerabilità e del sempre più accentuato stato di degrado di queste aree, diverse politiche ambientali sono state sviluppate con lo scopo di promuovere una gestione sostenibile delle risorse naturali, tra cui la Direttiva Quadro sulla Strategia per l’Ambiente Marino (2008/56/EC) in Europa. Le realtà economiche e sociali sono strettamente connesse tra loro e con i sistemi ecologici su cui poggiano. Per comprendere come l’uomo interagisce con l’ambiente, il modello concettuale DPSIR viene ampiamente adottato. Inoltre, sul piano strettamente ecologico, una solida conoscenza del funzionamento dell’ecosistema costiero costituisce un prerequisito fondamentale. Questa tematica complessa deriva dall’integrazione di parametri sia strutturali (caratterizzazione chimica e delle comunità biologiche) che funzionali (quali i principali processi di produzione primaria, respirazione e degradazione della sostanza organica), che nell’insieme descrivono come le varie forme di carbonio sono stoccate e come si realizza il fluire di carbonio ed energia attraverso il sistema. Lo studio del funzionamento dell’ecosistema bentonico costituisce uno strumento particolarmente utile nello sviluppare forme sostenibili di gestione ambientale dal momento che il dominio bentonico funge da deposito di ciò che avviene nella colonna d’acqua. I casi di studio presentati descrivono la parte PSI del modello concettuale DPSIR: come le Pressioni inducono cambiamenti nello Stato dell’ecosistema determinando di conseguenza alterazioni ambientali ed eventuali influenze negative sulle attività umane (Impatti). Lo scopo della tesi consiste nel contribuire a promuovere una gestione basata sull’ecosistema e sul suo funzionamento in aree costiere mediante una miglior conoscenza della sua funzionalità in presenza di specifici stress. I casi di studio vengono presentati secondo un ordine dettato dell’aumentare della complessità dell’approccio seguito: dal più semplice, caratterizzato solo da parametri strutturali, al più complesso, in cui sono stati indagati anche diversi parametri funzionali. La risposta della comunità microalgale bentonica (microfitobenthos - MPB) alle biodeposizioni derivanti dalle mitilicolture è stata studiata non solo paragonando una mitilicoltura con un controllo ma anche considerando le caratteristiche della comunità sotto ad un impianto più recente e in un’area dove l’attività è stata rimossa (Capitolo 2). Questo approccio innovativo permette di indagare l’evoluzione temporale dell’impatto e se è possibile un ripristino. Comparando le quattro aree, la comunità è caratterizzata da una maggiore proliferazione dei taxa tolleranti a condizioni di arricchimento organico sotto alle mitilicolture attive rispetto agli altri due siti. L’area dismessa, inoltre, presenta un popolamento microalgale simile a quello del controllo suggerendo la resilienza del sistema e, di conseguenza, una certa sostenibilità dell’attività di mitilicoltura. Tre comunità bentoniche sono state studiate sinotticamente in un’area costiera soggetta a stress multipli, come l’influenza del Po, la presenza di piattaforme per l’estrazione del gas e il prelievo/scarico di sedimenti (Capitolo3). Insieme alla caratterizzazione chimica, lo studio del MPB, della meiofauna e della macrofauna forniscono una descrizione dello stato dell’ecosistema bentonico in un esempio di monitoraggio che costituisce una base di dati a cui fare riferimento prima di qualsiasi intervento nell’area d’interesse. Lo studio di mesocosmo (Capitolo 4) è focalizzato sulla risposta della comunità microbica bentonica ad un abbassamento di pH dovuto alla fuoriuscita di CO2 da un suo sito di stoccaggio CCS (Carbon dioxide Capture and Storage). Costituisce un esempio di esperimento condotto in laboratorio con lo scopo di simulare eventuali scenari futuri derivanti da un intervento antropico in ambiente naturale prima della sua realizzazione. Relativamente a questo focus, sia i parametri strutturali (abbondanze picobentoniche, densità e composizione del MPB) che i funzionali relativi alla comunità microbica bentonica (attività enzimatiche, Produzione Procariotica di C e respirazione) sono stati studiati per la prima volta. I risultati suggeriscono che la comunità microbica è scarsamente sensibile anche ad un considerevole abbassamento di pH, probabilmente a causa di un effetto buffer esercitato dalla matrice sedimentaria. L’azione sinergica di idrocarburi e metalli pesanti sul funzionamento dell’ecosistema bentonico è stata studiata in un sistema fluviale-lagunare severamente contaminato (Capitolo 5). Numerosi parametri sono stati considerati e dalla loro integrazione deriva un’accurata descrizione del fluire di carbonio attraverso il sistema. I risultati relativi ai parametri microbici come le attività degradative, le produzioni primaria e secondaria e l’analisi del MPB, delineano una situazione inaspettata nel sito considerato più impattato. Il sedimento di tale stazione ospita infatti una comunità microbica bentonica estremamente attiva sia in termini di produttori primari che di procarioti volti al recupero della sostanza organica e conseguente conversione in nuova biomassa. Gli studi presentati in questa tesi non hanno la pretesa di costituire una descrizione esaustiva e completa del funzionamento dell’ecosistema bentonico, ma sottolineano l’importanza di questo approccio innovativo nel contribuire a sviluppare forme sostenibili di gestione delle risorse costiere.
Several human activities are settled along the coasts and rely on the ecosystem services provided by nature. The growing concern about the vulnerability of these areas promotes the development of environmental policies aimed at the sustainable management of the marine resources, such as the Marine Strategy Framework Directive (2008/56/CE) in Europe. Economic, societal and ecological systems are closely interlinked. For understanding how man interacts with the environment, the DPSIR conceptual model is largely adopted. Moreover, a robust knowledge on the coastal ecosystem functioning is needed as a prerequisite. This complex task derives by the integration of both structural (chemical and biological communities) and functional (processes as primary production, respiration and mineralisation) parameters which together describe the forms of carbon storage (organic and inorganic) and the flows of carbon and energy through the system. The study of the benthic ecosystem functioning is a tool particularly useful in developing sustainable management of coastal environments because the benthic domain acts as a repository of what happens in the overlying water. The four case-studies of my thesis focus on the PSI part of the DIPSIR conceptual model, i.e. on how Pressures translate into State changes which may, in turn, negatively affect the environment and the human activities (Impacts). The goal is to contribute in achieving an operational ecosystem-based management of coastal and shallow environments by improving the scientific knowledge on the functioning of shallow benthic ecosystems under specific pressures. The order of the papers is from the simplest to the most complex approach by adding the structural parameters first and then the functional ones. The response of the benthic microalgal community (microphytobenthos - MPB) to the mussel farm biodeposition has been investigated not only comparing the sediment beneath a mussel farm with a control site but also considering a relatively recent mussel farm and a disused one (Chapter 2). This innovative approach in the experimental design allows to study the temporal evolution of the mussel farming impact and the potential recovery of microphytobenthos. The community changes among the four areas with a more pronounced proliferation of those taxa that are tolerant to organic enrichment under the active mussel farms than in the other two sites. The disused farm is characterised by an assemblage similar to that of the control suggesting a resilience of the system and consequently the sustainability of this productive activity. Three benthic communities have been synoptically investigated in a shallow area subjected to multiple-stressor impacts such as the Po River influence, the presence of gas platforms, sediment dumping and sand extraction (Chapter 3). Together with some chemical parameters (Total Organic Carbon, Total Nitrogen, etc.), the synoptic study of different communities (MPB, meiofauna and macrofauna) gives a description of the state of the benthic ecosystem as an example of monitoring survey which represents the reference point for decision-makers prior to any kind of intervention. The mesocosm study (Chapter 4) focuses on the response of shallow benthic microbial communities to a decrease of pH due to the leakage of CO2 from a Carbon dioxide Capture and Storage (CCS) site. This is an example of a laboratory experiment aimed to simulate and predict the possible scenarios derived by an anthropogenic intervention in the natural environment before its actual execution. Benthic microbial structural (prokaryote abundance, MPB densities and composition) and functional parameters (exoenzymatic activities, Prokaryotic C Production and benthic respiration) have been investigated for the first time within this focus. Overall, the findings suggest a microbial community slightly sensitive to consistent pH decrease probably due to a buffer effect exerted by the sedimentary matrix. The synergistic impact of hydrocarbons and heavy metals on the benthic ecosystem functioning has been investigated in a severely contaminated Adriatic lagoon (Chapter 5). Several parameters have been considered in order to describe the overall flow of C through the system. The exoenzymatic activities, the Prokaryotic C Production, MPB composition and the Primary Production suggest an unexpected situation in the site that is considered the most impacted. The sediments at this station are inhabited by a microalgal community that is extremely active in fixing inorganic C through the Primary Production process. In addition, the occurrence of an efficient prokaryotic community in transforming the sedimentary organic C in new biomass, suggests a solid benthic microbial loop. These studies have not the pretence to describe exhaustively the benthic ecosystem functioning. Nevertheless they highlight the importance of this innovative approach in contributing to the development of a sustainable management of coastal resources.
XXV Ciclo
1984