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ISSN 1028334X, Doklady Earth Sciences, 2014, Vol. 458, Part 1, pp. 1158–1160. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © O.V. Stepanyan, 2014, published in Doklady Akademii Nauk, 2014, Vol. 458, No. 2, pp. 229–232.
1158
The assessment of the modern biodiversity of the
macroalgae of the Sea of Azov, the Black Sea, and the
Caspian Sea is of primary scientific importance, since
the alterations in the marine flora may serve as a reli
able marker of the effect of climate changes on the
marine biota [13].
The history of the botanical studies performed in
the southern seas of Russia started more than a hun
dred years ago. Largescale studies of the phytob
enthos of this area were conducted in the former
Soviet Union in the 1960s–1970s [2, 3]. After a rela
tive decline in the 1990s, the intensity of the algologi
cal research has increased significantly [1, 4, 6–9,
12,14]. However, an uptodate assessment of the
macroalgae diversity is absent for this region.
The material was collected in 2000–2012 in the Sea
of Azov, on the Russian coast of the Black and Caspian
seas, including both qualitative and quantitative sam
pling performed onboard R/V
Deneb
(2007–2012);
and an analysis of the previously published data has
been used.
A check list [3] was used as a basis for the regional
species list; the cluster analysis of this checklist
allowed us to define four groups of algae similar in
their frequency of occurrence and abundance. The
first group combines the algae species found in the
northwestern Black Sea; the second, most of the algae
inhabiting the northern Caucasus coast of the Back
Sea and Crimean coast; the third, the algae of the
southern and southwestern coasts of the Black Sea;
and the fourth, the macrophytes of the Sea of Azov, the
Caspian Sea, and the algae found in the “phyllophora
field of Zernov.” The analysis of the data [3] using the
Shannon–Weaver index allowed us to define the areas
of the highest species diversity. In the last century, such
areas included the northwestern coast of the Black
Sea, Novorossiysk Bay, Sevastopol Bay, and the south
ern Crimean coast. The species diversity of the mac
roalgae of the southern seas of Russia was studied in
detail in the mid1970s, except for the Turkish coast
[3]; 289 species were registered for the Black Sea;
33 species, for the Sea of Azov; and 47, for the Cas
pian Sea.
The analysis of the species diversity using the K
joining cluster method revealed that the model of the
species diversity was close in shape to the lognormal
distribution (the dominance of several species follow
ing by a small number of other species). This was true
for the Sea of Azov, for the Caspian Sea, for the north
western Black Sea, and for the “phyllophora field of
Zernov.” For the other studied areas, the model
approached the shape of the broken stick model (the
abundance of most of the species is nearly equal, and
no dominants are present).
The species list has increased since the mid1970s,
as it goes under the analysis of the flora of the Black
Sea, taking into account the new data obtained on the
Romanian, Bulgarian, Turkish, Ukrainian, Abkhazia,
and Russian coasts. Most of the findings of the new
Modern Diversity of the Macroalgae of the Sea of Azov,
the Black Sea, and the Caspian Sea
O. V. Stepanyan
Presented by Academician G.G. Matishov April 24, 2013
Received May 14, 2013
Abstract
—Currently, the species list of the macroalgae (excluding Charales) inhabiting the southern seas of
Russia includes 388 species, specifically, 362 species in the Black Sea, 46 species in the Sea of Azov, and
70 species in the Caspian Sea. The species list has been increased by approximately 30% (96 species, most of
them are registered in the Black Sea), compared to the data obtained 30 years ago. The green and red mac
roalgae of warmwater Mediterranean and tropical origin (
Ceramium
,
Polysiphonia
,
Laurencia
,
Ulva
, and
Chaetomorpha
) and brown algae (
Sargassum
and
Cytoseira
) were the key invaders. Nowadays the maximal
species diversity is found on the Crimean coast and the Turkish coast of the Black Sea; and the species list of
the Turkish coast differs significantly from all the other studied sites of the Black Sea. The number of the algae
of the warmwater complex increased the most in 1990s–2000s in the Black Sea; species of boreal–tropical
and subtropical origin dominate. However, such a tendency was not observed in the Sea of Azov and in the
Caspian Sea, but expansion of the habitats of the brackish green algae has been registered.
DOI:
10.1134/S1028334X14090220
Southern Research Center, Russian Academy of Sciences,
RostovonDon, Russia
email: step@sscras.ru
OCEANOLOGY
DOKLADY EARTH SCIENCES Vol. 458 Part 1 2014
MODERN DIVERSITY OF THE MACROALGAE 1159
species refer to the Turkish and Crimean coasts (Fig. 1).
Two groups of algae of the Black Sea have been defined
under cluster analysis, the northern group that refers
to the most freshened area of the Black Sea, and the
group of the other sea areas; alongside with that, the
macrophytes of the Turkish coast form an individual
cluster, which refers slightly to the other areas of the
Black Sea (Fig. 1).
Two big groups of the macroalgae may be defined in
regard to the preferred temperature regime, i.e., cold
water and warmwater. In the 1960s–1970s, the cold
water complex dominated and wideboreal species of
algae dominated [3]. Our studies evidenced that in the
1990s–2000s, the ratio of the warmwater algae
increased significantly, and boreal–tropical and sub
tropical species prevailed in the Black Sea (Fig. 1).
Such a tendency is linked to the increasing number
of findings of the new warmwater algae species in the
Black Sea [6, 10–12]. Some
Sargassum
species com
pete with the dominant algae of the upper sublittoral,
Cystoseira barbata
and
C. crinita
, and expand their
geographical range along the Black Sea, including the
Russian coasts [4].
The appearance of new algal species in the Black
Sea may also be linked to the increasing water temper
ature, the variability of the water salinity in the coastal
zone, and the increasing degree of eutrophication and
turbidity. Regard must be paid to all these factors that
are linked to each other, but the water temperature
increase should be named as the limiting factor for
algae growth and dissemination. In recent years, the
margin between the photic and aphotic zones (the
depth of sedentary algae growth) has decreased [6];
this process also affected the algae of the
Cystosira
spe
cies, which form the main complex of epiphytes in the
Black Sea. The conditions in the depth range of 15–50 m
are optimal for the growth of coldwater algae. The
increase in the water temperature, eutrophication, and
1.92
2.04
1.6
2.04
1.03
2.03
13
4
14
2567
2.15
2.19 2.26
2.09
1.56
2.14
7
8
9
10
11
2.07
2.01
2.27
13
12
BLACK SEA
1.03
2
1
2
3
1.67
CASPIAN SEA
12
14
13
9
6
7
5
8
11
10
4
2
3
1
III
050100
31%
69%
42%
58%
1960s
−
1970s 1990s
−
2000s
а
b
Similarity, %
Fig. 1.
Sampling sites and Shannon–Weaver index (
1
), probable invasion pathways of the algae with the currents (
2
) and from the
harbor areas (
3
). Numbers in the circles indicate the sampling sites: 1, Odessa city costal area; 2, “Phyllophora field of Zernov”;
3, Eroglytsko–Tendrovsko–Dzharylgachsko–Perekopskii district; 4, Karkinitskii Bay; 5, TarkhankutskSevastopol coast;
6, Sevastopol Bay; 7, southern coast of the Crimean Peninsula; 8, Prikerchenskii district; 9, Novorossiysk (Tsemess) Bay;
10, northeastern coast of the Black Sea; 11, southeastern coast of the Black Sea; 12, Turkish coast; 13, Bulgarian coast; 14, Roma
nian coast. Inset I: dendrogram of similarity of algae species diversity at different sites of the Black Sea. Inset II: ratio between the
warmwater (
a
) and coldwater (
b
) algae complexes in the Black Sea.
1160
DOKLADY EARTH SCIENCES Vol. 458 Part 1 2014
STEPANYAN
water turbidity leads together to shrinking of the geo
graphical range and to the total disappearance of the
native arcticboreal species inhabiting the Black Sea.
Similar reasons may be applied for the decrease in the
algal biodiversity observed on the northwestern coast
of the Black Sea (Odessa coast and “phyllophora field
of Zernov”), where the biodiversity index has
decreased by 28.4 and 12.1% since the 1970s, respec
tively. The economic activities (algae harvesting,
building in the coastal area, and pollution) also affect
the composition and the distribution of the algae
together with climate change. The effect of these fac
tors was the most obvious in the “phyllophora field of
Zernov,” where the stock of the red coldwater algae
was wiped out over half a century. Alongside with that,
ballast waters are the origin of different invasions,
including algae of the coldwater complex. The arc
tic–boreal brown alga
Desmarestia viridis
is a good
example; this species was first registered close to the
city of Odessa in 1990. Over 20 years, the range of this
species has increased insignificantly, mostly along the
Romanian coast of the Black Sea; however, it is still
localized in the coldest part of the Black Sea; the
southern findings belonging to the area of the cities of
Anapa and Novorossiysk were not confirmed.
In the Sea of Azov and in the Caspian Sea, the ratio
of warmwater species remains the same, but the range
of the brackish green algae has expanded, which is
linked to the variability of the water salinity here [15].
Harsh winters occurring every 8–10 years in the Sea of
Azov and in the northern and central Caspian Sea
restrict the expansion of the ranges of the warmwater
species; during that cold period, the ice may cover the
habitats for more than 100 days [5].
Currently, the species list of macroalgae (except
Charales) of the southern seas of Russia comprises
388 species, specifically, 362 in the Black Sea, 46 in
the Sea of Azov, and 70 in the Caspian Sea. The species
list has increased by approximately 30% (96 species,
most of them are registered in the Black Sea), com
pared to the data obtained 30 years ago. The green and
red macroalgae of warmwater Mediterranean and
tropical origin (
Ceramium
,
Polysiphonia
,
Laurencia
,
Ulva
, and
Chaetomorpha
) and brown algae (
Sargassum
and
Cytoseira
) are the key invaders. Representatives of
the coldwater complex, especially the arctic–boreal
group, have become rare or extinct. The number of
macroalgae species in the phytogeographic regions of
the Black Sea has changed, but the scheme of princi
pal regions proposed by KaluginaGutnik [3] remains
current. Regard must be paid to the decrease in the
biodiversity of the coldwater complex with simulta
neous increase in the warmwater complex; a similar
tendency has been observed in the temperate seas of
the Northern Hemisphere [13].
Invasive species are the most dangerous; they
spread actively in the Mediterranean Sea, and more
than ten of them are found in the Black Sea (in total,
there are more than 100 invasive species) [11]. Most
probably, the three key species may penetrate and set
tle down in the Black Sea,
Undaria pinnatifida, Sar
gassum muticum
, and
Caulerpa taxifolia
.
U. pinnatifida
and
S. muticum
are characterized by a high rate of the
vegetative reproduction and high ecological plasticity;
they are able to displace
Cystosira
species from their
native biotopes.
C. taxifolia
is a toxic green algae that
suppresses the growth of the seaweed
Zostera marina
and
Z. noltii.
In the Mediterranean Sea, the invasion of
this species has already led to the disappearance of
most of the seaweed beds and intensification of the
shore abrasion processes.
Expansion of the alien macroalgae species, espe
cially of the warmwater complex, is already taking
place. The major areas in which we expect the appear
ance of invasive species are the largest harbors
(Novorossiysk, Tuapse, Poti, Odessa, Constance, Bur
gas) and the southern and the southeastern Black Sea,
including the northern Caucasus coast (Fig. 1).
REFERENCES
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Macrophyte Algae and Seaweeds of the
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Biological
Productivity of the Southern Seas of Russia
(Naukova
dumka, Kiev, 1974), pp. 43–51 [in Russian].
3. A. A. KaluginaGutnik,
Phytobenthos of the Black Sea
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Translated by D. Martynova
