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Identifier |
000447593 |
Title |
Απόκριση διαφορετικών πλαγκτονικών κοινοτήτων σε προσθήκη διαλελυμένου οργανικού άνθρακα |
Alternative Title |
Response of different plankton communities to a single addition of dissolved organic carbon (DOC) |
Author
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Κτιστάκη, Γεωργία Ξ.
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Thesis advisor
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Πήττα, Παρασκευή
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Reviewer
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Καρακάσης, Ιωάννης
Λύκα, Κωνσταντίνα
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Abstract |
The addition of dissolved organic carbon (DOC) from terrestrial to coastal, marine or freshwater
ecosystems colors the water yellow-brown. This phenomenon is called “brownification” and causes
shading, affecting primary production. In addition, increasing the concentration of organic carbon
can lead to increased production and biomass of heterotrophic organisms, with potential
consequences on the whole food web. The present study focused on the effect of this phenomenon
on marine plankton groups. The effect was simulated in an mesocosm experiment by adding
HuminFeed to seawater. The mesocosm experiment took place at CretaCosmos facility of H.C.M.R.
in June 2021 and had 2 treatments: Control (C) and HuminFeed (HF) with 3 replicates for each
treatment. No manipulation was performed in C while in HF, HuminFeed was added at a
concentration of 2 mg L-1
. The experiment lasted 15 days during which it was observed that the
addition of HuminFeed caused brownification and reduced light penetration causing a decrease in
the abundance of strictly autotrophic organisms (Synechococcus cyanobacteria and diatoms).
However, no clear effect on nanoflagellates was recorded, possibly due to the mixotrophy observed
in this group. In addition, HuminFeed was a source of DOC for the bacterial community. Although
the abundance of bacteria was greater, mainly during the first days of the experiment, the
abundance of HNA (High Nucleic Acid) bacteria was higher in the HF condition during the whole
experiment, which is reflected in the increased bacterial production. In the HF treatment, an
increased abundance of dinoflagellates was observed, which may be due to either a dominance of
mixotrophic species or to a decrease in the abundance of their predators (copepods). However, the
decrease in ciliate abundance recorded immediately after the addition of HuminFeed to the
seawater probably indicates that its addition to the water was responsible for their number
reduction and their altered form. Finally, HuminFeed seems to have had a negative effect on the
copepods, as well.
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Language |
Greek |
Subject |
Brownification |
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Mesocosm |
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Microbial ecology |
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Διαλελυμένος οργανικός άνθρακας |
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Μεσόκοσμος |
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Μικροβιακή οικολογία |
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Πλακτόν |
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Χρωματισμός των νερών |
Issue date |
2022-07-29 |
Collection
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School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/8/d/f/metadata-dlib-1649856204-28849-23329.tkl
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Views |
371 |