African Journal of Aquatic Science Water

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African Journal of Aquatic Science
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Water quality assessment and application of the
biological diatom index in the Kebir-East wadi,
Algeria
N Chaïb a & J Tison-Rosebery b
a
b Cemagref Bordeaux, Unité de Recherche Réseaux, Epuration et Qualité des Eaux, 50
avenue de Verdun, 33610, Cestas, France
Available online: 02 Apr 2012
To cite this article: N Chaïb & J Tison-Rosebery (2012): Water quality assessment and application of the biological diatom
index in the Kebir-East wadi, Algeria, African Journal of Aquatic Science, 37:1, 59-69
To link to this article: http://dx.doi.org/10.2989/16085914.2011.636898
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Laboratoire de Recherche et de Conservation des Zones Humides (Université de
Guelma, Algeria), Faculté de Technologie, Université du 20 Août 1955, Skikda, Algeria

African Journal of Aquatic Science 2012, 37(1): 59–69
Printed in South Africa — All rights reserved
Copyright © NISC (Pty) Ltd
AFRICAN JOURNAL OF
AQUATIC SCIENCE
ISSN 1608-5914 EISSN 1727-9364
http://dx.doi.org/10.2989/16085914.2011.636898
African Journal of Aquatic Science is co-published by NISC (Pty) Ltd and Taylor & Francis
The biotic components of running water systems are
important parameters for the assessment of water quality
(Stanford and Ward 1988, Junk 1999, Stoermer and Smol
1999, de la Rey et al. 2008). To assess the ecological status
of water bodies, taxonomic composition, abundance and the
ratio of sensitive to insensitive taxa have to be considered
as biological indicators of water quality. However, knowledge
of the biotic components of North African rivers or wadis is
relatively poor and these water systems remain some of the
least-studied Mediterranean ecosystems. Up to now Algerian
wadis have been scantily studied, particularly concerning
their ecological aspects (e.g. Lounaci et al. 2000), even
if they represent interesting natural conditions as they
are strongly influenced by an accentuated Mediterranean
climate, including extreme temperature values during
summer and short, extreme flooding events followed by long
dry periods. There is a considerable lack of knowledge about
possible environmental conditions and biological changes
that these hydrosystems are likely to experience in the light
of pollution or climatic changes. Most studies of Algerian
wadis have been confined to their physicochemical charac-
teristics and macroinvertebrates (Lounaci et al. 2000, Belaidi
et al. 2004), whereas studies on algae, particularly diatoms,
are rare (Baudrimont 1973).
Diatoms are a key component of aquatic ecosystems.
They respond directly and rapidly to many environmental
parameters such as geology (Stevenson 1997, Pan et al.
2000), current velocity (Peterson and Stevenson 1990),
and nutrients (Potapova and Charles 2003). Their species-
specific sensitivity to different parameters varies according to
species physiology, leading to a large group of assemblage
compositions according to ecological conditions (Licursi
and Gomez 2002, Potapova and Charles 2002, Tison et al.
2005). Knowledge of how the interactions of geographical
and environmental factors drive the distribution patterns of
benthic diatom species in Algerian wadis is crucial for the
development of future water quality assessment tools that
are adapted to this particular context.
The aims of the present study were to survey the benthic
diatom communities of the Kebir-East wadi, to relate their
distributional patterns to environmental variables, and to test
the reliability of the biological diatom index in this instance
(Lenoir and Coste 1996, Coste et al. 2009).
Materials and methods
Study area
The Kebir-East wadi, north-eastern Algeria, extends over a
length of 96 km from the junction of Leben and Mellili wadis
in the east to its confluence with the Mafragh River in the
west (Figure 1). The climate is typically Mediterranean with
a dry and hot summer and with rainfall occurring mostly
during the winter months.
The Kebir-East wadi represents a mosaic of geo-
morphodynamic natural conditions, as well as diverse levels
of man-made disturbances of a variety of origins (physical:
Water quality assessment and application of the biological diatom index in
the Kebir-East wadi, Algeria
N Chaïb1* and J Tison-Rosebery2
2 Cemagref Bordeaux, Unité de Recherche Réseaux, Epuration et Qualité des Eaux, 50 avenue de Verdun, 33610 Cestas, France
* Corresponding author, e-mail: [email protected]
A total of 118 benthic diatom taxa were recorded during a survey in 2007 of the Kebir-East wadi, north-eastern
Algeria. Fourteen samples were collected at seven sampling stations in winter and summer. The majority of diatom
taxa comprised cosmopolitan species widely distributed along the hydrosystem. Canonical correspondence analysis,
used to examine spatial patterns of diatom communities in relation to environmental gradients, was statistically
highly significant (p < 0.001). The first axis accounted for 45% and the second for 22% of the total variance. Seasonal
and physicochemical gradients were clearly defined and indicated the water quality. A cluster analysis was then
carried out to represent the different groups of the sampled stations sharing the same flora. Agglomerative cluster
analysis grouped the sampled sites into seven clusters according to the community data. For clusters gathering
more than one single sample, typical diatom taxa were determined with an indicator species analysis. The reliability
of the biological diatom index BDI 2007 was tested under our environmental conditions and it was concluded that,
considering the very particular geochemical context of this wadi, a specific diatom index should be developed.
Keywords: BDI 2007, canonical correspondence analysis, cluster analysis, environmental gradients, IndVal analysis
Introduction
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1 Faculté de Technologie, Université du 20 Août 1955 Skikda, Algeria. Laboratoire de Recherche et de Conservation des Zones
Humides, Université de Guelma.

Chaïb and Tison-Rosebery
60
Bouhalloufa and Mexa dams; chemical: presence of
non-point pollutions, and municipal wastes). The substratum
of the Kebir-East wadi is composed either of ancient
sediments (marls and sandstone) of the Algerian local
marine Miocene (equivalent to the continental Aquitanien),
degraded slightly on the surface in the east, or more recent
Plio–Quaternary sediments corresponding to alluviums of
the high and average terraces of the Kebir-East wadi valley.
The recent Quaternary sediments in the valley of Kebir-East
wadi comprise silt, sand and stones (Marre 1987).
Over the winter and summer of 2007, a total of 14 samples
were examined (see Table 1). Seven sampling sites were
selected across a gradient of pollution from near farmlands
and from near-pristine to heavily urbanised areas. The sites
sampled on the main course of the Kebir-East wadi (Figure 1)
show a wide range of conductivity (300–900 μS cm−1),
alkalinity (16–128 mg l−1 of CaCO3), and pH (6.5–8.3). The
particular geochemical context leads to high conductivities
(>500 μS cm−1) often associated with low pH (<7).
Farmlands surround the Kebir-East wadi, and the
farmers use a considerable amount of water to irrigate
their farms and provide drinking water for their cattle.
Sampling sites are characterised by deep and fast-flowing
waters during the winter and shallow slow-flowing waters
during the summer. Station A was situated within the
El Kala National Park (PNEK), created in 1983, added to
the National Heritage list and classified as a Biosphere
Reserve by UNESCO in 1990. The Kebir-East wadi in this
non-urbanised area is surrounded by farmlands and flows
on a sandstone land. Station B at Aïn Assel, situated not far
from Mexa dam, is transformed into pools in summer and
autumn. The presence of slaughterhouses near Stations
C and E impacts the water quality of the Kebir-East wadi,
in addition to municipal wastes of Aïn Khiar and Bouteldja
towns, which discharge directly into the wadi. Station D
receives the polluted water of Guergour wadi, which is
highly impacted by sewage of the Guergour conglomeration.
Stations F and G, located at Righia and Sebaa conglom-
erations, respectively, were also surrounded by farmlands.
The waters of these stations were deeper (0.5–1.6 m), and
the flow velocities recorded were high in winter and low in
summer.
Dataset
Samples of diatoms were collected according to a standard-
ised method, NFT90-354 (AFNOR 2000), from five randomly
chosen stones representing a total surface area of 100 cm2.
The stones were scraped with a toothbrush and the pooled
material was stored in dark bottles containing 5% formalde-
hyde. Diatom species were identified at 1 000× magnifica-
tion under a Zeiss light microscope (400 valves per slide),
by examining permanent slides of cleaned diatom frustules,
digested in boiling H2O2 (30%), and HCl (35%), and mounted
in a high refractive index medium (Nafrax, RI = 1.74).
Taxa were identified according to Süsswasserflora von
Mitteleuropa (Krammer and Lange-Bertalot 1985–1991)
and complementary works (Patrick and Reimer 1966, 1975,
Germain 1981, Hartley et al. 1996, Kelly 2000).
Water quality measurements and water samples were
collected during the winter and summer seasons of 2007
at each site. Sixteen water quality variables (pH, conduc-
tivity, turbidity, oxygen saturation, dissolved oxygen, current
velocity, temperature, alkalinity, nitrates, nitrites, orthophos-
phates, sulphates, chlorides, ammonium, calcium and
AFRICA
36°50′ N
8°15′ E8°30′ E
36°45′ N
7° E
Lake
Oubeira
MEDITERRANEAN SEA
MEDITERRANEAN SEA
Aïn Assel
Bouteldja
El Tarf
A
B
C
D
E
F
G
Mexa
Dam
05 10 km
K
e
b
i
r
-
E
a
s
t
W
a
d
i
K
e
b
i
r
-
E
a
s
t
W
a
d
i
Bou Lathan
Dardan
Zitoun
Guergour
Mafragh
Bourdim
Qued
Messida
Bougous
Louar
Leben
Mellili
Boumershene
Degrah
TUNISIA
ALGERIA
ALGERIA
Algeria
Sampling site
Wadi
River
EL TARF
LEGEND
Enlarged area
Figure 1: Map of the study area indicating locations of sites in the Kebir-East wadi, north-eastern Algeria, sampled in 2007
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African Journal of Aquatic Science 2012, 37(1): 59–69 61
magnesium) were measured at mid-depth where the diatoms
were collected. All chemical variables were analysed with
a laboratory photometer 5000 according to the colorimetric
method, and measured in mg l−1. Temperature and conduc-
tivity were measured in situ with an Ecoscan con5 conduc-
timeter. Water pH was measured using a 209-HANNA pH
meter. Turbidity was measured with an Aqualytic turbidim-
eter. Saturation and dissolved oxygen were measured with
an oxymeter. The current velocity was measured vertically
with a Global Flow Probe (FP101-FP201).
Data analysis
Relative abundances of species were transformed by
natural algorithm in order to reduce their variation range. To
avoid a problem of logarithm zeroes, the value 1 was added
to each abundance.
Groups of samples sharing the same type of community
composition were defined using a hierarchical cluster
analysis (Goodall 1973), with Ward’s linkage method and
Euclidian distance measure. Multi-response permuta-
tion procedures (MRPP; Biondini et al. 1985) were used to
test the reliability of the groups obtained. Typical species
for each cluster were determined with an indicator species
analysis (IndVal; Dufrêne and Legendre 1997). This method
combines information on the concentration of species
abundances in a particular group and the faithfulness of
occurrence of a species in a particular group. Indicator
values were tested for statistical significance using a
randomisation (Monte Carlo) technique (McCune and Grace
2002). Agglomerative cluster analysis, MRPP and indicator
species analysis were performed with the software PCord
4.25 (McCune and Mefford 1999).
To look for ecological determinants of diatom
assemblages along the Kebir-East, we used canonical
correspondence analyses (CCA; ter Braak 1986, ter Braak
and Verdonschot 1995), a two-table ordination method
performed using the ADE-4 package in the R environ-
ment (Thioulouse et al. 1997, Thioulouse and Dray 2007,
R Development Core Team 2009). This multivariate analysis
tool has been used to ordinate samples by searching for a
co-structure between physicochemical variables and diatom
species. The correlation in CCA was carried out between
the two new sets of projected coordinates. The signifi-
cance of the resulting correlation (R-value) between the two
sets of coordinates resulting from the CCA was tested by
carrying out 1 000 canonical correspondence analyses of
the environmental descriptors and the diatom datasets after
random permutations of their rows (ter Braak 1986).
Cluster and indicator species analysis results were used
for the interpretation of the CCA graph and to highlight the
more typical species. Cluster memberships were specified
on the CCA graph and indicator species were underlined.
The biological diatom index (BDI 2007) scores were
determined using OMNIDIA 5.3 (http://omnidia.free.fr). For
each sample, the community of diatoms was described with
species relative abundance.
Richness, diversity and evenness indices were also
calculated (Shannon and Weaver 1949). Evenness
accounts for both abundance and evenness of the species
present, and assumes a value between 0 and 1 with 1 being
complete evenness.
Site Site
code Stn Season NO3
(mg l−1)
NO2
(mg l−1)
NH4
(mg l−1)
PO4
(mg l−1)
Turb
(NTU)
Currvel
(cm s−1)
O2sat
(%)
O2dis
(mg l−1)
Temp
(°C)
Cl
(mg l−1)
Cond
(μS cm−1)
TAC
(mg l−1
CaCO3)
pH SO4
(mg l−1)
Ca
(mg l−1)
Mg
(mg l−1)
Kebir at R’Mel Souk KeRSk AS 12.0 0.3 0.2 0.1 42.0 19.4 155.4 15.6 15.0 225.0 768.0 68.0 6.8 217.0 114.0 116.0
W 9.2 0.2 0.1 0.1 97.0 63.8 160.7 18.7 8.6 162.0 771.0 58.0 7.2 185.0 77.0 116.5
Kebir at Ain Assel KebAs BS 16.4 0.8 1.0 0.5 1 065.5 4.0 109.6 11.6 17.6 93.0 556.5 96.5 7.3 159.5 86.0 142.5
W 17.2 0.4 0.1 1.2 217.0 38.8 145.8 16.8 9.0 158.0 380.0 128.0 6.5 190.0 138.0 120.0
Kebir at Ain Khiar KebAK CS 21.7 0.1 0.6 0.7 534.0 13.0 91.4 8.2 20.6 103.0 680.0 50.0 6.9 133.0 72.0 26.0
W 21.0 0.3 0.6 0.4 87.0 31.9 101.1 11.6 9.2 114.2 416.0 27.0 6.7 16.5 51.0 20.0
Kebir at Guergour KebGrg DS 19.8 0.2 0.0 3.1 288.0 11.5 113.3 10.5 18.7 159.0 864.0 48.0 8.3 131.0 118.0 76.0
W 5.5 0.2 0.7 0.6 257.0 44.3 136.7 16.2 7.9 247.0 683.0 92.0 7.1 167.0 59.0 145.0
Kebir at Ouled Anenes KebAn ES 7.9 1.2 0.2 0.9 970.0 10.3 111.0 10.1 19.9 105.0 759.0 31.0 7.1 128.0 77.0 22.0
W 7.8 0.6 0.1 0.9 124.0 37.1 102.4 11.6 9.7 210.0 1 048.0 20.0 6.8 125.0 29.0 17.0
Kebir at Righia KebRg FS 10.3 1.4 0.1 1.1 97.0 14.6 111.5 9.8 21.6 111.0 760.0 20.0 7.4 178.0 134.0 27.0
W 10.3 0.8 0.1 0.9 654.0 39.1 102.5 11.7 9.4 171.0 407.0 40.0 7.0 116.0 47.0 35.0
Kebir at Sebaa KebSb GS 7.9 0.6 0.1 1.1 336.0 11.4 110.1 10.6 17.0 144.0 758.0 43.0 6.6 155.0 83.0 119.5
W 8.2 0.4 0.1 1.0 176.0 25.0 109.3 12.5 9.3 118.0 386.0 17.0 6.9 120.0 33.0 123.0
Table 1: Physicochemical variables of water at the Kebir-East wadi sampling sites in winter and summer 2007. Stn = station (see Figure 1), S = summer, W = winter, Turb = turbidity, Currvel = current velocity, O2sat = saturation of oxygen, O2dis = dissolved oxygen, Cond = conductivity, TAC = alkalinity
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Chaïb and Tison-Rosebery
62
Results
The 118 diatom taxa from 43 genera determined from our
14 samples belong to the key taxa list used by BDI 2007.
See Appendices 1 and 2 for diatom species abbreviations
and counts, and Table 2 for floristic diversity and BDI 2007
values. Ecological characteristics of species were derived
from van Dam et al. (1994). Measured values for the
physical and chemical variables (n = 14) in the Kebir-East
wadi are presented in Table 1.
The agglomerative cluster analysis (Figure 2) grouped
the sampled sites into clusters according to the community
data. We chose the seven-groups level of the dendrogram,
the MRPP results showing that the groups obtained were
statistically different (A = 0.303, p < 0.005). For clusters
gathering more than one single sample, typical species were
determined with an indicator species analysis. Indicator
values are given in Table 3, along with statistical signifi-
cance values calculated by randomisation (Monte Carlo)
KeRSkS
KebAKS
KebGrgS
KeRSkW
KebAsW
KebAKW
KebGrgW
KebRgW
KebSbW
KebAsS
KebRgS
KebAnS
KebAnW
KebSbS
2.8E+00
100
3.6E+01
75
7E+01
50
1E+02
25
1.4E+02
0
DISTANCE (objective function)
INFORMATION REMAINING (%)
Species Group Value p*
CEUG 1 100.0 0.0390
CPLA 1 100.0 0.0390
NPAL 1 39.3 0.0410
NCTV 1 49.2 0.0420
NGRE 1 50.4 0.0490
NDIS 1 51.0 0.0280
NLAN 1 51.5 0.0550
SBRE 1 52.0 0.0210
CPED 1 54.5 0.0430
TAPI 1 56.2 0.0180
CSOL 1 66.4 0.0340
NCTO 1 71.7 0.0200
MALC 3 100.0 0.0050
NCPL 3 100.0 0.0050
GPUM 3 50.9 0.0180
CMEN 3 70.0 0.0250
NCPR 3 76.8 0.0160
CTUM 6 100.0 0.0430
NIFR 6 38.0 0.0160
NRCS 6 62.2 0.0520
NFIC 6 73.8 0.0120
PSBR 6 76.1 0.0100
SEMN 6 79.2 0.0290
* Significance levels of the permutation tests
Table 3: Diatom indicator species by group (IndVal analysis). See
Appendix 1 for explanation of species codes
Figure 2: Agglomerative cluster dendrogram based on diatom communities sampled in the Kebir-East wadi in 2007. IndVal was calculated for
the three clusters (1, 3 and 6) that gathered more than one sample. See Table 1 for site codes (S= summer, W = winter) and Table 3 for results
Site code Total
counted Richness Diversity Evenness BDI 2007
KeRSkS 409 46 4.26 0.77 11.7
KebAKS 402 45 4.22 0.77 11.8
KeRSkW 401 50 4.31 0.76 11.0
KebSbW 402 50 4.38 0.78 11.6
KebAKW 400 47 4.11 0.74 11.3
KebGrgW 406 41 4.07 0.76 10.7
KebRgW 400 43 3.93 0.72 9.9
KebGrgS 401 55 4.46 0.77 11.6
KebSbS 408 42 4.13 0.77 10.9
KebAsW 400 50 4.16 0.74 11.9
KebRgS 400 43 4.39 0.81 9.2
KebAnS 426 27 2.87 0.60 8.0
KebAnW 408 29 3.11 0.64 8.0
KebAsS 414 16 1.47 0.37 18.0
Table 2: Floristic diversity and BDI 2007 values for the sampling
sites in summer and winter 2007. See Table 1 for site codes (S =
summer, W winter)
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