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International Journal of Marine Science 2014, Vol.4, No.17: 160-165
http://ijms.sophiapublisher.com
160
Research Report Open Access
Emiliania huxleyi
Spring Bloom in the Black Sea: A Tentative Investigation
L.V. Stelmakh , E.Yu. Georgieva
The A.O. Kovalevsky Institute of Biology of the Southern Seas National Academy of Sciences of Ukraine, 2, Nakhimov av., Sevastopol 99011, Crimea,
Ukraine
Corresponding author email:
lstelm@ibss.iuf.net
,
lustelm@mail.ru
International Journal of Marine Science, 2014, Vol.4, No.17 doi: 10.5376/ijms.2014.04.0017
Received: 20 Dec., 2013
Accepted: 20 Jan., 2014
Published: 24 Feb., 2014
Copyright
©
2014 Stelmakh and Georgieva, This is an open access article published under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Stelmakh and Georgieva, 2014,
Emiliania huxleyi
Spring Bloom in the Black Sea: A Tentative Investigation, International Journal of Marine Science, Vol.4,
No.17: 160-165 (doi: 10.5376/ijms.2014.04.0017)
Abstract
This investigation was carried out in the surface water layer of some coastal and open-sea zones of the Black Sea in May
2013 when a spring bloom of
Emiliania huxleyi
was developing. The numbers of
E. huxleyi
in the blooming sea surface varied from
1.3 to 4.3·10
6
cell/l amounting on the average to 94 % of the total phytoplankton abundance. The bloom emerged as a response to
favourable light, temperature and nutrient conditions which have accelerated the phytoplankton growth to 0.80 – 1.44 d
-1
while the
predatory pressure of microzooplankton on this coccolithophore remained low. High net growth rate of the phytoplankton (0.40 –1.00
d
-1
) and low ratios of the specific microzooplankton grazing rate to the specific phytoplankton growth rate (34% on the average) in
the seawater area can be interpreted as the evidence of beginning bloom.
Keywords
Black Sea; Phytoplankton growth rate; Microzooplankton grazing; Chlorophyll-
a
Introduction
Blooms of
Emiliania huxleyi
(Lohmann) Hay &
Mohler 1967 have been repeatedly registered all over
the global ocean including the Black Sea
(Morozova-Vodyanitskaya, 1957;
Tyrrell and Merico,
2004;
Pautova et al., 2007; Stelmakh et al., 2013). It
was proposed that as the abundance of this
coccolithophore is estimated 1×10
6
cell/L and more, it
is a bloom and the plentiful microalgae change optical
properties of the sea water so that satellite imagery
reports of “white water” (Balch et al., 1991;
Tyrrell
and Merico,
2004).
The triggering mechanism of this
phenomenon has not been clearly understood as yet.
The known factors causing outbreaks of this
coccolithophore species are primarily light,
temperature and nutrients; biotic relations in the
plankton are also of key importance. For instance, the
surveys made in the Bering Sea during
E. huxleyi
bloom (July – August 1999) provided evidence that in
the blooming sea water average specific rate of
microzooplankton grazing on the phytoplankton was
three times lower than the specific growth rate of the
phytoplankton (Olson and Strom, 2002). The authors
supposed that the low predatory impact has been the
key to formation of the summer
E. huxleyi
bloom.
By carrying out this investigation we intended to gain
insight firstly into the spatial variability of specific
growth rate of the phytoplankton and the rate of
phytoplankton consumption by microzooplankton in
relation to the spring bloom in the surface of the Black
Sea, and secondly into the role these processes in
formation of
E. huxleyi
bloom.
1 Data and Methods
Samples of plankton were taken from the surface
water layer of the Black Sea at some near-shore and
open-sea areas from 20 to 29 May 2013 during the
72
nd
expedition of the RV “
Professor Vodyanitsky
”
(Figure 1). The surveys were carried out in the western
(to 34° E) and eastern (34 – 37º E) parts of the sea.
Figure 1 Location of sampling stations