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International Journal of Marine Science 2013, Vol.3, No.15, 121-127
http://ijms.sophiapublisher.com
121
Research Article Open Access
Microzooplankton Grazing Impact on Phytoplankton Blooms in the Coastal
Seawater of the Southern Crimea (Black Sea)
L.V. Stelmakh
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: lustelm@mail.ru
International Journal of Marine Science, 2013, Vol.3, No.15 doi: 10.5376/ijms.2013.03.0015
Received: 28 Feb., 2013
Accepted: 29 Mar., 2013
Published: 07 Apr., 2013
Copyright
©
2013 Stelmakh, 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, 2013, Microzooplankton Grazing Impact on Phytoplankton Blooms in the Coastal Seawater of the Southern Crimea (Black Sea), International
Journal of Marine Science, Vol.3, No.15 121
-
127 (doi: 10.5376/ijms.2013.03.0015)
Abstract
The investigation of seasonal dynamics of microzooplankton specific grazing rate was carried out in the near-shore sea
off the southern Crimea (Black Sea) during 2006~2007 and 2010. It is shown that microzooplankton grazing depended on the
abundance and quality of prey. The favorite prey items were diatoms
Skeletonema costatum
and
Chaetoceros
spp. When
microzooplankton grazed less than 80% of the primary production, the peaks of phytoplankton biomass were recorded in this study.
The average annual removal of primary production by microzooplankton was estimated as weighty as 65%. Such estimated values
indicate the key role of the microzooplankton in exporting matter and energy from phytoplankton to higher trophic levels.
Keywords
Black Sea; Phytoplankton growth rate; Microzooplankton grazing; Chlorophyll-
a
Introduction
Microzooplankton is generally considered as hetero-
trophic and mixotrophic organisms able to switch to
phagotrophy, with individual linear dimensions lesser
than 200 µm (Calbet and Landry, 2004; Calbet, 2008).
Protozoa and early life stages of mesozooplankton as
well as larval stages of benthic animals are all
microzooplankton. Protozoa are represented by
flagellates, including dinoflagellates, ciliates and
small foraminifers (Sherr and Sherr, 2007; Calbet,
2008). Measurements performed in seawater areas of
all known types point out that, on the average,
heterotrophic flagellates contribute to the total
microzooplankton biomass as large as 64% (Sherr and
Sherr, 2009). Early developmental stages of
mesozooplankton are mainly nauplii of copepods
(Calbet, 2008). Until recently, the investigations
conducted over the Black Sea have only assessed the
biomass produced by individual groups of
microzooplankton (Zaika and Averina, 1968;
Pavlovskaya, 1976; Polikarpov et al., 2003) setting
aside the associated functional aspects, in particular
the rates of microzooplankton grazing on
phytoplankton. Research in this field began in 2005,
during the international expedition to the western
Black Sea on board of the R/V “Vladimir Parshin”
(Stelmakh et al., 2009). These results confirm that
microzooplankton is the major consumer of
phytoplankton in the World Ocean. On the average,
70% of the primary production in the open sea and
about 60% in the coastal zone are removed by
microzooplankton (Calbet, 2008). Some authors
(Sherr and Sherr, 2007) interpret the predatory
pressure of protozoa, primarily heterotrophic
dinoflagellates, on diatoms, as an effective tool
regulating bloom formation. Knowing that annual
primary production in the Black Sea is mainly due to
diatoms (Stelmakh et al., 1998), clarifying the role
that microzooplankton plays in formation of diatom
blooms appears the task of high priority.
For gaining insight into this aspect, we studied
seasonal dynamics of microzooplankton predatory
pressure on the phytoplankton blooms which emerged
near the shores of Sevastopol and village Katsiveli,
the latter situated eastward on the Crimean coast of
the Black Sea.
1 Results
1.1 The seasonal dynamics of the specific rate of
microzooplankton grazing
In 2006~2007, the observations related to micro-
zooplankton predatory pressure on phytoplankton in the