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Basic Research Journal of Soil and Environmental Science ISSN 2345-4090 Vol. 2(4) pp. 51-56 December 2013
Available online http//www.basicresearchjournals.org
Copyright ©2012 Basic Research Journal
Full Length Research Paper
Interactions between phytoplankton, zooplankton and
fish in the Massa estuary
*1Badsi Hind, 2Oulad Ali Hassan, 3Loudiki Mohammed, 4Aamiri Ahmed
1
Laboratory of Oceanography and Limnology, Department of Biology, Faculty of Sciences, Ibn Zohr University, Agadir,
Morocco.
2
Laboratory of Oceanography and Limnology, Department of Biology, Faculty of Sciences, Ibn Zohr University, Agadir,
Morocco.
3
Laboratory of Biology and Biotechnology of Microorganisms, Department of Biology, Faculty of Sciences, Semlalia Cadi
Ayyad University, Marrakech, Morocco.
4
Laboratory of Oceanography and Limnology, Department of Biology, Faculty of Sciences, Ibn Zohr University, Agadir,
Morocco.
*Corresponding author email: [email protected]
Accepted 18 December 2013
The interactions between phytoplankton and zooplankton was studied from march 2009 to April 2011 at
seven stations. In spite of large weekly variations in the abundance and community structure,
phytoplankton and zooplankton usually showed an obvious inverse relationship during different
periods. However, the density of phytoplankton seems to be due to the existence of unfavorable
phytoplankton species to be grazed by zooplankton. The grazing appeared to be affected by the
environmental conditions, like salinity, a temperature, also the species composition of both
phytoplankton and zooplankton communities. The preliminary study of stomcal contents of Chelon
labrosus and Mugil cephalus fish species showed that their food spectra clearly dominated by algae.
Keyword: Massa estuary, phytoplankton, zooplankton, fish, stomacal contents.
INTRODUCTION
The simultaneous study of the phytoplankton and
zooplankton communities is crucial for understanding the
functioning of the ecosystem. It is well known that the
density, species composition and size distribution of
phytoplankton are controlled not only by nutrient
conditions, but also by the zooplankton (Sarnelle, 1993;
Kivi et al., 1993).
The impact of physicochemical parameters and phytozooplankton interactions have been several studies
limnology, for against the role of fish on the structure and
dynamics of ecosystems has been less studied (Persson
et al., 1988). Fish predation to impact on zooplankton on
phytoplankton and other biotic component (Lazzaro and
LacroixG, 1995).
This study is a contribution to the understanding of the
structure of the food web of the estuary of Massa and we
present here the results of studies of the interactions
between phytoplankton community and the population of
zooplankton on the one hand and the relationship
between the two phyto- zooplankton communities with
predation by fish inhabit the Massa estuary .
MATERIAL AND METHODS
The sampling stations were chosen to allow us to meet
Badsi et al. 52
Figure 1. The Study area and positions of sampling stations
the objective of our study and taking into account a
number of factors including the representativeness of the
estuary for many spatially identify the importance of
stations and accessibility, seven stations, are selected
(figure 1). Phytoplankton and zooplankton were collected
with a bottle “Wildco” kind to collect a volume of water to
any depth desired.
For phytoplankton study, 6 liters of water were
collected at each station, preserved in 4% neutralized
formaldehyde. The supernatant water was then decanted
and the concentrated were examined for species
identification and counting. For zooplankton 6 liters of
water were collected at each stations and preserved in
5%formol and then examined and counted. Principal
component analysis was employed to detect the
correlations between the different groups of both
phytoplankton and zooplankton.
We chose two types of fish Chelon labrosus and Mugil
cephalus wich have a wide geographical distribution and
grouping both tropical, subtropical and temperate
regions. Several studies have been devoted (Ameur,
1994; El Housni, 1988; Ould, 1892).
RESULT AND DISCUSSION
Interaction between Phytopalnkton and Zooplankton
before the floods
The comparative evolution of phytoplankton and
zooplankton populations has allowed us to observe a lack
of proportionality in particular before the opening of the
sand dune. This could be related to poor quality algae
and the effect of predation by fish and plankton larvae
Chaoborus. Frequent blooms of Microcystis aeruginosa
are hardly grazed by species zooplankton.
The high abundance of phytoplankton at the closed and
shallow estuary Massa suggests that primary producers
in this phase are not controlled by grazing due to the
presence of unpalatable species and low nutritional
value, the small zooplankton as it is the group of Rotifers
herbivors, scavengers that dominate the estuary and the
absence of large of Cladocera especially downstream.
The analysis of large phytoplankton and zooplankton
groups (figure 2) showed associations between Rotifers
(Brachionus plicatilis , Brachionus urceolaris and
53. Basic Res. J. Soil Environ. Sci.
Figure 2. Principal Component Analysis of the phytoplankton and
zooplankton groups before the floods.
Hexarthra fennica) Harpacticoid (Epactophanes richardi,
Moraria sp) and Cyanophyceae (Microcystis aeruginosa,
Anabaena sp) The associations we observed are similar
to those observed in several studies that have shown a
positive correlation between Rotifers and proliferations of
Cyanobacteria in systems having a tendency to
eutrophication (Bonecker et al., 2001; Leonard and Paerl,
2005). The association between potentially toxic
Cyanobacteria (Microcystis aeruginosa, Gloeocapsa
turgida and Anabaena sp) and some species of
zooplankton (Rotifers: the genus Brachionus) in Massa
estuary is consistent with several studies showing that
some zooplankton species can coexist in the presence of
toxins produced by cyanobacteria. Indeed, (Ferrao-Filho
et al., 2009a) have shown that Cyanobacterial toxins may
be responsable for the predominance of more resistant
species such as Copepods and Rotifers,
Similarly, data analysis based on major taxonomic
groups at Massa shown that Cladocerans (Chydorus
sphearicus, Ceriodaphnia reticulata and Ceriodaphnia
quardangula) and Calanoides (Diaptomus sp) are
negatively correlated with the Cyanophyceae (Microcystis
aeruginosa, Gloecapsa turgida). This is due to the
inefficiency of these large grazers to consume
filamentous Cyanobacteria. The downstream stations
(Ameur, 1994; Bonecker et al., 2001; El Housni, 1988)
where eutrophication is accentuated because of the low
water renewal are associated with groups of
phytoplankton (diatoms and Cyanophyceae) and
zooplankton (Rotifers).
At the upstream sector (Gliwicz, 1994; Haddad, 1996;
Heinbokel et al., 1988), where eutrophication is less
acute is with more transparent waters are associated with
diatoms and Chlorophyceae for phytoplankton, the
Rotifers, Cladocerans and Cyclopoid for zooplankton
(Figure 2).
Interaction between Phytopalnkton and Zooplankton
after the floods
After the opening of the estuary (Figure 3), the first
factorial explains 88.60% of variance, with 73.68% for the
first axis. It is observed that Dictyophyceae (Dictyocha
fibula) and Dinophyceae (Prorocentrum micans,
Alexandrium minutum) are positively correlated to
Calanoides (and "other organizations" zooplankton,
Chlorophyceae (Merismopedia, Scenedesmus falcatus)
and Euglenophycées (Euglena texta) are positively
correlated with Cladocerans (Ceriodaphnia reticulata,
Bosmia longirostris) and Cyclopoid and oppose
Cyanophyceae (Scenedesmus). Zygophyceae that are
related to rotifers (Polyarthra vulgaris). Cyclopoid and
Cladocera and have a very strong correlation between
them and have a positive relationship with
Euglenophycées and diatoms (Cyclotella ocellata,
Navicula cryptocyphala...). These groups show a
negative
association
with
marine
Calanoides
(Centropages typicus Paracalanus parvus) (Figure 3). On
the Axis 2 (14.92%) was observed that diatoms
Badsi et al. 54
Figure 3. Principal Component Analysis on the phytoplankton and
zooplankton groups after the floods.
(Cyclotella ocellata, Navicula cryptocephala) are
associated with Calanoides (Diaptomus sp) and oppose
Cladocerans
(Ceriodaphnia
reticulata,
Bosmina
longirostris), the cyclopoid (Tropocyclops prasinus,
Acanthocyclps robustus) and Rotifers (Brachiouns
plicatilis, Polyarthra vulgaris). Latter group shows a
positive
correlation
with
Zygophyceae
and
Cyanophyceae.
We found a correlation between the densities of
phytoplankton and Zooplankton. This may be due to two
main factors: nutrient regeneration by Zooplankton, which
leads to an increase in Phytoplankton abundance, and
the effect of predation on fish inhabit the Massa estuary
on Zooplankton community that fosters the development
phytoplankton. The pressure of zooplankton grazing on
phytoplankton is less pronounced especially at the
downstream sector as it is populated by small species
(Rotifers) and less than Copepods. Downstream, in
addition to Rotifers, Copepods we have engaged a
grazing Cladocera more on phytoplankton species. This
observation explain the significant correlation between
groups of dominant Zooplankton (Rotifers, Copepods and
Cladocerans) and most groups of Phytoplankton
(Diatoms,
Cyanophyceae,
Chlorophyceae
and
Euglenophyceae at the Massa estuary. Befor the floods,
predation intra- Zooplankton in the Massa estuary has a
role in the structuring Zooplankton communities through
association predator - prey. In our study, Asplanchna
priodonta is mainly associated with rotifers of the genus
Brachionus, which are potential prey for this species.
Indeed, the sharp decline of Brachionus plicatilis for
development Asplanchna priodonta in summer 2009
including at stations 4 and 5 confirms that Brachionus is
diet favorable Asplanchna priodonta.
After the flood, we did not observe an effect of grazing
on
phytoplankton.
Indeed,
the
dinoflagellate
Prorocentrum micans is impreferable Zooplankton
species and this species could have a harmful effect on
Calanoides
grazers
who
peuplement
estuary
downstream. It is therefore concluded that the
Dinoflagellates seem to be not preferable by different
zooplankton during the present study, a case which is in
agreement with (Ismael and Abdel-Aziz, 2003) who
reported that the dinoflagellates Prorocentrum micans, P.
minimum and P. triestinum are unsuitable food for microand meso-zooplankton. (Heinbokel et al., 1988) noted
that rotifers often constituting the dominant grazer on the
dinoflagellates.
Befor the floods both Rotifers Brachionus plicatilis and
Brachionus urceolaris feed Cyclotella ocellata and
Navicula cryptocephala, and we have seen the
development of two species of Rotifers, which coincides
with the decline of two Phytoplankton species, such as in
March 2009, we noted a peak due to intense
development,
Cyclotella
ocellata
and
Navicula
cryptocephala , which is accompanied by low densities of
both Rotifers Brachionus plicatilis and Brachionus
urceolaris. A reverse relationship was observed between
55. Basic Res. J. Soil Environ. Sci.
Polyarthra vulgaris and two Cyclops Tropocyclops
parasinus and Acanthocyclops robustus and saw the
development of Polyarthra vulgaris in July and August
2009 and is accompanied by low densities or even the
disappearance of the two Cyclops Tropocyclops
parasinus and Acanthocyclops robustus and aims to it.
This allows us to conclude that the two Cyclops show
selectivity for food of Polyarthra vulgaris. Our findings
therefore bring a similar result compared to the literature
(Gliwicz, 1994).
For phytoplankton population, both Cyclops show a
selectivity of the diatom Cyclotella ocellata. In fact,
usually the peak densities of the two Cyclops in April and
October 2009 caused significant decrease in the
abundance of Cyclotella ocellata this allows us to suggest
the use of this diatom small by Cyclops.
The abundance of large grazers (Calanoides and large
Cladocera) is generally observed during the absence or
in the reduction of Cyanobacteria which is in agreement
with the observation of (Lampert, 1987).
Interaction between fish and plankton
Fish-phytoplankton:
101 stomcal contents was examined, the results show
that the stomach contents of both species are similar.
They show the dominance of phytoplankton.
The analysis of the diet of both species shows that in
terms of biomass the phytoplankton population is better
represented in the digestive tract of fish. Differs result
from what has been found by Haddad (1996). Indeed, the
presence of phytoplankton in the contents of digestive
tracts indicates that these fish could contribute to
improving the water quality in the Massa estuary by
reducing algal biomass.
*Mugil cephalus: phytoplankton fraction consists of
diatoms (Bacillariophyceae (95%), Cyanophyceae (3%)
and Euglenophyceae (2%).
*Chelon labrosus: phytoplankton fraction includes
pinnate and centric diatoms (94%), Cyanophyceae (4%)
and Euglenophyceae (2%).
Fish Fish –zooplankton
*Mugil cephalus: animal fraction is represented by 43%
attributed to Copepods, Cladocerans 29% and 19% of
Rotifers.
*Chelon labrosus: stomach contents is presented by
41% copepods, 27% of 18% of cladocerans and rotifers
14% ostracods. This is especially eggs of Brachionus and
individuals who dominate.
The low percentage densities of zooplankton in the
stomach contents of two species in relation to
phytoplankton biomass relative contribution and energy
intake of zooplankton could be relatively higher than that
of phytoplankton.
The results obtained in this study revealed the
adaptation of the two species to trophic environmental
conditions
CONCLUSION
The interaction between phytoplankton and zooplankton
is regulated by environmental factors, the composition
and abundance of the two communities. The Zooplankton
is committed by either selective or non- selective
mechanisms, but sometimes a species of Zooplankton
can toggle between the two mechanisms depending on
the composition of Phytoplankton available.
The
interaction
between
Phytoplankton
and
Zooplankton in the estuary Massa is regulated by
environmental factors, grazing by Zooplankton and the
composition and abundance of both phyto- zooplankton
communities. Indeed, zooplankton grazing is committed
by either selective or non- selective mechanisms, based
on the composition of phytoplankton available.
The study of diet showed a diet mainly
Zoophytoplanctonophage for both species with different
food preferences. A broad food spectrum reflecting the
adaptation of these species to trophic environmental
conditions. The high Phytoplankton fraction constituting
the gut contents of fish fauna studied is strongly reduced
Phytoplankton biomass.
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