Feeding ecology and impacts of microplastics and heavy metals in Nephrops norvegicus (Linnaeus, 1758) within the North Euboea Gulf

Postgraduate Thesis uoadl:3414316 72 Read counter

Unit:
Κατεύθυνση Γεωλογική Ωκεανογραφία
Library of the School of Science
Deposit date:
2024-08-29
Year:
2024
Author:
Dantsi Christina
Supervisors info:
Μεγαλοφώνου Περσεφόνη Καθηγήτρια – Τμήμα Βιολογίας, ΕΚΠΑ (Επιβλέπουσα)
Μπότσου Φωτεινή Μέλος ΕΔΙΠ Α´ – Τμήμα Χημείας, ΕΚΠΑ
Αναστασοπούλου Κατερίνα Ερευνήτρια Β´ – ΕΛΚΕΘΕ
Original Title:
Οικολογία διατροφής και επίδραση μικροπλαστικών και βαρέων μετάλλων στο είδος Nephrops norvegicus (Linnaeus, 1758) στον Βόρειο Ευβοϊκό κόλπο
Languages:
Greek
Translated title:
Feeding ecology and impacts of microplastics and heavy metals in Nephrops norvegicus (Linnaeus, 1758) within the North Euboea Gulf
Summary:
This thesis aims to investigate the feeding habits and diet of Nephrops norvegicus in the North Euboea Gulf, Greece, as well as to examine microplastic concentrations in their stomach contents and heavy metal concentrations in their tissue. For this study, the stomach contents of 203 N. norvegicus individuals were analyzed to assess their diet and the presence of microplastics. Additionally, the concentrations of heavy metals (Hg, Ni, Cr, Cu, Fe, Zn) in the tail tissue of these individuals were measured.
The length-weight relationship between molted and non-molted individuals revealed positive allometric growth in both cases, with a higher coefficient b observed in non-molted individuals (3,10 compared to 2,38). Additionally, a higher coefficient b was observed between the sexes, with males exhibiting a coefficient of 3,10 and females 2,47. According to the diet study of the species, twelve taxonomic groups were identified. The main categories of prey, based on their contribution to the species' diet, in decreasing order, were: Decapods (41%) > Crustaceans (11%) > Sponges (10%) > Gastropods (9%) > Echinoderms (4%) > Scaphopods (3%) > Polychaetes (2%) > Amphipods (2%) > Holothurians (1,5%) > Cephalopods (1%) > Fishes (0,1%), whereas unidentifiable material was found in 11%. Statistically significant difference were observed on the diet between the sexes (χ2<0,05) and the seasons (χ2<0,05), but no statistically significant difference were observed between size classes (χ2>0,05).
Microplastics (MPs) were detected in 79,3% of the total population of the individuals. The abundance of MPs ranged from 1 to 35 particles per individual, with an average of 3,72 ± 4,78/particles per individual, indicating a relatively high presence compared to existing literature. Polymer fibers constituted the majority (90,9%) in comparison to fragments (2%) and substantial proportions (7,1%) of polymer fiber aggregates were identified, especially during the summer season. The four predominant colors of MPs were white (24,7%), black (24,3%), transparent (24,1%), and red (17,1%), with other colors accounting for less than 4% each. The MPs composition was nylon (62.5%), polyester (31.2%), and unidentified material (6.2%). Statistically significant difference were observed between the mean abundance and length of the MPs among seasons (p<0,05). No statistically significant differences were observed between the mean abundance of MPs and the biological parameters such as sex (p>0,05), molt status (p>0,05) class size (p>0,05) and with the stomach content weight (p=0,18, R2=0,09).
The concentrations of heavy metals were examined in relation to the sex, season and size of the animals. In ascending order, the metal concentrations (mean value, mg/kg dry weight) were as follows: Hg (0,57) < Cr (1,53) < Ni (2,00) < Cu (18,28) < Fe (44,16) < Zn (46,18). Hg concentrations increased (R2=0,21, p<0,05) with the growth, while Cr concentrations decreased (R2=0,27, p<0,05) with the growth of the species. In addition, the Target Hazard Quotient (THQ) was lower than 1, the risk to human health from consuming crustaceans from the N. Euboean Gulf is negligible.
Main subject category:
Science
Keywords:
Nephrops norvegicus, Norway Lobster, Feeding ecology, Microplastics, Heavy metals, East Mediterranean Sea, Aegean Sea, North Euboea gulf
Index:
No
Number of index pages:
3
Contains images:
Yes
Number of references:
362
Number of pages:
203
File:
File access is restricted until 2027-08-29.

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