Offshore platforms used for hydrocarbon extraction represent a potential source of anthropogenic impact for benthic communities and the entire marine ecosystem. As soon as the extraction shaft runs out, the platform is closed and then abandoned. This activity, called "decommissioning", represents a serious problem for the health and conservation of the marine environment and its biodiversity. Although the platforms have several negative impacts on the marine environment and its associated fauna. Some scientists have provided data to support the beneficial role of drilling rigs, which can serve as a substrate for the growth of benthic organisms, in particular mussels and oysters, and fads (Fishing Aggregating Device) or artificial devices capable of attracting fish populations. Because of the many economic and environmental problems that decommissioning entails and the increasing number of platforms that have come to an end from their productive life present at a global level, some scientists have proposed alternatives that may have a lower impact on the environment. Among the most accredited alternatives was the "Rigs-to-reefs" which consists in the conversion of Offshore structures into artificial barriers that support the hot-spots of biodiversity. This thesis is part of the PON Place project, which aims at the creation and implementation of an innovative process to optimize the different technologies applicable to the offshore platform "Viviana" located in the Adriatic Sea off the coast of Giulianova (Abruzzo), and its conversion to an eco-sustainable multifunctional use. The main objective of this thesis is to evaluate if there have been changes in the level of macrobenthic populations present in the area around the platform following the placement of electrification structures, aimed at increasing mineral growth, and the placement of cages used to test the integrated multitrophic farming of molluscs and holothurites, which could generate an increase in organic load through their excretion products. For this purpose, the data obtained from the sampling carried out in July and October 2021 (T1 and T2) were compared carried out at 50m, 500m and 2km from the platform after the installation of the electrified structures and the cages used for the integrated breeding experiment were compared with those obtained from a previous thesis in which the samples were analysed collected in October 2019 (T0), prior to the positioning of the structures themselves. The results of this thesis have shown how the activities of disturbance of the sediment due to the deposition of the structures associated with the PON Place project, have mainly influenced the macrobenthic communities closest to the platform (50 m) and in time T1, three months after installation operations. The community appears to show signs of recovery already at time T2, about 6 months after the sediment disturbance operations. Our results seem to suggest that where we found a disturbance in the area, especially in stations located 500m and 2km from the platform, this could be related to the presence of external factors to the installed structures. This study suports the idea that the choice of platform decomissioning has to be valued by specific case. and the alternative uses tested do not represent a problem for the surrounding benthic communities. In addition, it is assumed that it is preferable, in cases similar to the one tested in the project, not to proceed with removal techniques that may have impact on surrounding communities.
Le piattaforme Offshore utilizzate per l’estrazione di idrocarburi rappresentano una potenziale fonte di impatto antropico per le comunità bentoniche e l’intero ecosistema marino. Nel momento in cui il pozzo estrattivo si esaurisce, la piattaforma viene chiusa per essere poi successivamente dismessa. Tale attività, detta “decommissioning”, rappresenta una problematica seria per la salute e la conservazione dell’ambiente marino e della sua biodiversità. Nonostante le piattaforme abbiano diversi impatti negativi sull’ambiente marino e la fauna ad esso associata, alcuni scienziati hanno fornito dati a sostegno del ruolo benefico degli impianti di perforazione, che possono fungere da substrato per la crescita di organismi bentonici, in particolare mitili ed ostriche, e da FADs (Fishing Aggregating Device) ovvero dispositivi artificiali in grado di attirare popolazioni di pesci. Visti i numerosi problemi economici e ambientali che il decommissioning comporta e il crescente numero di piattaforme giunte al termine dalla loro vita produttiva presenti a livello globale, alcuni studiosi hanno proposto delle alternative che possono avere un minor impatto sull’ambiente. Tra le alternative più accreditate si è fatta strada quella del “Rigs-to-reefs” che consiste nella riconversione di strutture Offshore in barriere artificiali che sostengano degli hot-spot di biodiversità. Questa tesi si inserisce nell’ambito del progetto PON Place, il quale mira alla creazione e all’implementazione di un processo innovativo per ottimizzare le diverse tecnologie applicabili alla piattaforma offshore “Viviana” situata nel Mar Adriatico al largo della costa di Giulianova (Abruzzo), ed alla sua conversione verso un utilizzo multifunzione eco-sostenibile. L’obiettivo principale di questa tesi è quello di valutare se ci sono stati dei cambiamenti al livello dei popolamenti macrobentonici presenti nell’area attorno alla piattaforma in seguito al posizionamento di strutture di elettrificazione, volte a favorire l’aumento dell’accrescimento minerale, e al posizionamento di gabbie usate per testare l’allevamento multitrofico integrato di molluschi e oloturie, il quale potrebbe generare un aumento in termini di carico organico attraverso i loro prodotti di escrezione. A tal fine, sono stati confrontati i dati ottenuti dai campionamenti condotti a luglio ed ottobre 2021 (T1 e T2) effettuati a 50m, 500m, 2km di distanza dalla piattaforma dopo l’installazione delle strutture elettrificate e delle gabbie utilizzate per l’esperimento di allevamento integrato sono stati confrontati con quelli ottenuti da una precedente tesi in cui sono stati analizzati i campioni raccolti ad ottobre 2019 (T0), precedentemente al posizionamento delle strutture stesse. I risultati della presente tesi hanno evidenziato come le attività di movimentazione del sedimento dovute alla deposizione delle strutture associate al progetto PON Place, abbiano influenzato prevalentemente le comunità macrobentoniche più prossime alla piattaforma (50 m) e nel tempo T1, tre mesi dopo le operazioni di installazione. La comunità sembra mostrare segni di recupero già al tempo T2, ovvero a circa 6 mesi dalle operazioni di movimentazione. I nostri risultati sembrano suggerire che laddove si riscontri una situazione di disturbo nell’area, soprattutto nelle stazioni situate a 500m e 2km dalla piattaforma, questa potrebbe essere correlata alla presenza di fattori esterni alle strutture installate. Tale studio supporta l’idea che la scelta di decommissioning della piattaforma debba essere caso-specifica e che gli utilizzi alternativi qui testati non rappresentino una problematica per le comunità bentoniche circostanti. Inoltre, si ipotizza che sia preferibile, in casi simili a quello testato nel progetto, di non procedere con tecniche di rimozione che possono avere conseguenze impattanti sulle comunità circostanti.
Monitoraggio del macrozoobenthos di fondo mobile associato alle attività di conversione di Piattaforme Off-Shore per usi multipli eco-sostenibili
PREMICI, ALICE
2020/2021
Abstract
Offshore platforms used for hydrocarbon extraction represent a potential source of anthropogenic impact for benthic communities and the entire marine ecosystem. As soon as the extraction shaft runs out, the platform is closed and then abandoned. This activity, called "decommissioning", represents a serious problem for the health and conservation of the marine environment and its biodiversity. Although the platforms have several negative impacts on the marine environment and its associated fauna. Some scientists have provided data to support the beneficial role of drilling rigs, which can serve as a substrate for the growth of benthic organisms, in particular mussels and oysters, and fads (Fishing Aggregating Device) or artificial devices capable of attracting fish populations. Because of the many economic and environmental problems that decommissioning entails and the increasing number of platforms that have come to an end from their productive life present at a global level, some scientists have proposed alternatives that may have a lower impact on the environment. Among the most accredited alternatives was the "Rigs-to-reefs" which consists in the conversion of Offshore structures into artificial barriers that support the hot-spots of biodiversity. This thesis is part of the PON Place project, which aims at the creation and implementation of an innovative process to optimize the different technologies applicable to the offshore platform "Viviana" located in the Adriatic Sea off the coast of Giulianova (Abruzzo), and its conversion to an eco-sustainable multifunctional use. The main objective of this thesis is to evaluate if there have been changes in the level of macrobenthic populations present in the area around the platform following the placement of electrification structures, aimed at increasing mineral growth, and the placement of cages used to test the integrated multitrophic farming of molluscs and holothurites, which could generate an increase in organic load through their excretion products. For this purpose, the data obtained from the sampling carried out in July and October 2021 (T1 and T2) were compared carried out at 50m, 500m and 2km from the platform after the installation of the electrified structures and the cages used for the integrated breeding experiment were compared with those obtained from a previous thesis in which the samples were analysed collected in October 2019 (T0), prior to the positioning of the structures themselves. The results of this thesis have shown how the activities of disturbance of the sediment due to the deposition of the structures associated with the PON Place project, have mainly influenced the macrobenthic communities closest to the platform (50 m) and in time T1, three months after installation operations. The community appears to show signs of recovery already at time T2, about 6 months after the sediment disturbance operations. Our results seem to suggest that where we found a disturbance in the area, especially in stations located 500m and 2km from the platform, this could be related to the presence of external factors to the installed structures. This study suports the idea that the choice of platform decomissioning has to be valued by specific case. and the alternative uses tested do not represent a problem for the surrounding benthic communities. In addition, it is assumed that it is preferable, in cases similar to the one tested in the project, not to proceed with removal techniques that may have impact on surrounding communities.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12075/8253