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PRELIMINARY STUDIES OF ALGAE IN NATURA 2000 SITE - ILGAS (LATVIA)

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PRELIMINARY STUDIES OF ALGAE IN NATURA 2000 SITE - ILGAS (LATVIA)

PRELIMINARY STUDIES OF
ALGAE IN NATURA 2000 SITE
ILGAS (LATVIA)
Anastasiia Snigirova1, Victoriia Berezovska2, Mihails Pupins3
1Institute of marine biology NAS of Ukraine
2M.G. Kholodny Institute of Botany NAS of Ukraine
3Daugavpils University, Institute of Life Sciences and Technologies
The Microreserve Ilgas is a marsh natural protected area of Natura 2000,
with whole-European importance, located south from the City of
Daugavpils, Latvia. The natural reserve was established for protection of
the northernmost population of the European fire-bellied toad, Bombina
bombina, a protected species in Latvia (Pupiņš, 2019).
The aim of the study was to evaluate the biodiversity of microalgae and
the intensity of productive processes.
Materials and methods
The study was provided in
Microreserve Ilgas Natura 2000
(55.691217, 26.771125) in September
2019
Microphytobenthos (red arrows) was
sampled using a standard Ekman Grab
from 0.51 m depth
Periphyton (yellow arrows) was
sampled from aquatic vegetation
Phytoplankton of total volume of one
liter was sampled from the water
surface
Materials and methods
In the laboratory, the phytoplankton sample was concentrated using
sedimentation method, proving the volume to 100 ml.
Silt and clay were isolated from the sample using 35 kHz ultrasound
during 10-20 min (Nevrova et al., 2015). The cells were counted under
light microscope Bresser (Institute of marine biology, Ukraine).
For all primary producents, the number of cells was calculated using
Fuchs-Rosenthal (0.012 ml volume) counting chamber.
Photos were made on Zeiss Axioskop-40 (Daugavpils University, Latvia).
Results
In total of 81 microalgae species were registered
in phytoplankton, periphyton and
microphytobenthos in Ilgas. Among them are
Bacillariophyta (43 species), Chlorophyta (11
sp.), Charophyta (14 sp.), Euglenophyta (9 sp.),
Dinophyta (2 sp.), Chrysophytata (2 sp.) and
Xanthophyta (1 sp.).
The genera Navicula, Fragillaria and Cocconeis
were most numerous. Eunotia and Euglena had
high biomass with low frequency. Diverse
groups were genera Pinnularia, Gomphonema,
Epithemia.
7
43
13
25
number of species in studied biotopes
plankton silt rocks plants
Results
Most part of phytoplankton biomass (97.7%) was
formed by dinoflagellates, represented mainly by
Peridinium cinctum (O.F.Müller) Ehrenberg. The
euglenoids Trachelomonas volvocinopsis Svirenko
composed up to 30% by frequency.
N, 1000 cells ×·l-1 B, mg ×·m-3
phytoplankton
940.27 42862.41
Results
N, 1000 cells
×·cm-
2
B, mg ×·cm-2
Microphyto-
benthos 151.77 160.90
86-97 % of phytobenthos biomass was
formed by diatoms. Euglenoids (8-12%) and
desmids (1-5%) were prevailed by biomass.
Three species (Navicula radiosa Hustedt,
Epithemia turgida (Ehr.) Kütz, Pinnularia
flexuosa Cleve, were prevailed in silt by
frequency.
Structure of algal community of phytoplankton
(PhP) and microphytobenthos (MPhB) in Ilgas
Taxa Biotope Abundance Biomass
1000 cells
×cm-2/l-1 %mg·сm-2/m-3 %
Bacillariophy
с
eae
PhP 16.40 1.74 67.83 0.16
MPhB 149,41 98,52 147,21 91,88
Chlorophyceae
PhP 2.73 0.29 7.15 0.02
MPhB 0,98 0,51 0,68 0,38
Euglenophyceae
PhP 314.33 33.43 881.62 2.06
MPhB 0,55 0,36 9,39 5,23
Dinophyceae
PhP 601.33 63.95 41886.27 97.72
MPhB 0,20 0,11 0,29 0,16
Charophyta
PhP 5.47 0.58 19.53 0.05
MPhB 0,63 0,50 3,33 2,35
Results
In periphyton, the most numerous
species were green algae Botryococcus
braunii Kütz, Zygnematophyceae
Spirogyra sp. and colonial diatoms
Fragilaria virescens Ralfs, but also
euglenoids (genera Lepocinclis and
Phacus), green algae (Pediastrum duplex,
Ankistrodesmus falcatus), desmids
(Staurodesmus sp., Cosmarium sp.) and
dinoflagellates (Ceratium cornutum (Ehr.)
Claparèdeet J. Lachmann, Peridinium
cinctum).
Interesting findings
We also noted two interesting algal taxa -
Characium acuminatum A.Braun and
Desmidium aptogonum Brébisson ex
Kützing. The least species is a rare species
in the flora of Latvia and we noted it in
second since Н. Skuja record (Skuja, 1928).
Conclusions
The most number of species were found in microphytobenthos (43)
and periphyton (25).
In Ilgas we observed very high biomass of phytoplankton, probably
because of low numbers of samples and the period of sampling end
of summer, when the highest intensity of autotrophic processes takes
place.
Based on ecological features of species we may resume that the lake
related to mesotrophic type of reservoir (Barinova et al., 2019).
Further investigations of microalgae diversity in dynamics will help to
supplement and clarify our information, and will also become the
basis for subsequent analysis.
Thank you very much
for your attention!
Project in the frame of Latvian - Ukrainian cooperation
program No LV-UA/2018/6: "The ecological and biological
triggers of expansion of the invasive fish, Chinese sleeper
(Perccottus glenii), in Eastern Europe".
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