OCEANOGRAPHIC STUDY OF THE SARONIKOS GULF (OCTOBER 2017) WITH EMPHASIS ON THE DISTRIBUTION OF THE SUSPENDED PARTICULATE MATTER

Postgraduate Thesis uoadl:2881988 382 Read counter

Unit:
Κατεύθυνση Γεωλογική Ωκεανογραφία
Library of the School of Science
Deposit date:
2019-10-02
Year:
2019
Author:
Talagani Pinelopi
Supervisors info:
Σεραφείμ Πούλος, Καθηγητής Τμήματος Γεωλογίας και Γεωπεριβάλλοντος ΕΚΠΑ
Εμμανουήλ Δασενάκης, Καθηγητής Τμήματος Χημείας ΕΚΠΑ
Σοφιανός Σαράντης, Επίκουρος Καθηγητής Τμήματος Φυσικής ΕΚΠΑ
Original Title:
ΩΚΕΑΝΟΓΡΑΦΙΚΗ ΜΕΛΕΤΗ ΤΟΥ ΣΑΡΩΝΙΚΟΥ ΚΟΛΠΟΥ (ΟΚΤΩΒΡΙΟΣ 2017) ΜΕ ΕΜΦΑΣΗ ΣΤΗ ΔΙΑΣΠΟΡΑ ΤΟΥ ΑΙΩΡΟΥΜΕΝΟΥ ΥΛΙΚΟΥ
Languages:
Greek
Translated title:
OCEANOGRAPHIC STUDY OF THE SARONIKOS GULF (OCTOBER 2017) WITH EMPHASIS ON THE DISTRIBUTION OF THE SUSPENDED PARTICULATE MATTER
Summary:
During the sailing of ship “AEGEO” of HCMR in the Saronikos Gulf in October 2017, samples of surface sediments and water were collected and measurements of water temperature, salinity, density anomaly, concentration of oxygen, beam transmission and fluorescence using CTD were made. Most of the 17 surface sediments are characterized as sandy Muds (sM) and the remaining ones as Muds (M). The Mz values of the samples range from 4.18 φ to 7.74 φ, are characterised by poor to very poor classification (σΙ: 1.85 φ to 2.67 φ) and are almost symmetrical or with positive to very positive symmetry (SKI values from -0.01 φ to -0.75 φ). Sediment are classified also as platykurtic and mesokurtic, since KG takes values of 0.67–1.11 φ with the exception of the sample from the position EL3 in the Elefsis Bay, which is leptokurtic. Based on the CTD measurements, vertical and horizontal distribution patterns of water parameters are produced with the use of ODV software. Then, these results are compared to those extracted from a previous cruise, in March 2017. The water column in October consists of a surface layer of up to 60 m above the seasonal thermocline (in Elefsis Bay the thermocline is 20 - 25 m), overlaying on an annual thermocline (70 - 120 m), while the deep waters reach the depth of 405 m. In March, a surface layer up to 10-15 m lies on top of the pycnocline/thermocline that extends to about 30 m and which is placed above a transitional layer extending to the depth of 120 - 130 m. Below this depth, deep waters reach the depth of 407 m. Surface SPM values range from 5.39 mg/L to 8.66 mg/L, at intermediate depths between 5.83 mg/L and 7.25 mg/L and above seabed from 5.70 mg/L to 15.98 mg/L. The correlation of Beam Transmission - SPM measurements is good near the bottom with R values being 0.61-0.88. The grain settling velocity in Saronikos Gulf is estimated from 0.002 cm/s to 0.28 cm/s, which means that grains need from less than one day to 118 days to settle. The grains are resuspended by the currents when the Shields ratio θ takes values between 0.18 - 2.2, which is associated with near bed currents at a velocitity of 0.40 - 0.50 m/s for bed roughness (ks) equal to Mz (graphic mean grain diameter) and velocity of 0.24 - 0.26 m/s for ks = 1cm.
Main subject category:
Science
Keywords:
Sediments, CTD, SPM, settling, resuspension
Index:
Yes
Number of index pages:
1
Contains images:
Yes
Number of references:
65
Number of pages:
85
ΩΚΕΑΝΟΓΡΑΦΙΚΗ ΜΕΛΕΤΗ ΤΟΥ ΣΑΡΩΝΙΚΟΥ ΚΟΛΠΟΥ (ΟΚΤΩΒΡΙΟΣ 2017) ΜΕ ΕΜΦΑΣΗ ΣΤΗ ΔΙΑΣΠΟΡΑ ΤΟΥ ΑΙΩΡΟΥΜΕΝΟΥ ΥΛΙΚΟΥ.pdf (5 MB) Open in new window