An ecological survey of Littoral Rotifera from some selected areas of Iraq: II. South of Iraq

Naeem Shanad Hammadi

Fishereries and Marine Resources, Agriculture College, Basrah University, Iraq.

*Corresponding Author E-mail:nae71em@yahoo.com

Abstract:

To increase an ecological information on Iraqi rotifers I collected rotiferan samples from fourteen different waterbodies in the governates of Southern Iraq, two of them at Al-Qadisiyyah: The five Shuhada Bridge (1) and Corniche of Diwaniyah (2); two stations at Al-Muthanna: Corniche of Samawah (3) and Al-Shuhada Bridge (4), three stations at ThiQar: Euphrates River (5), Alwafa canal (6) and Al-Holindi Bridge (7);  three stations atMaysan: Al-Shuhada Bridge (8), Nazim Al-Kahla River (9) and Nazim Al-Musharah River (10) and four stations at Basrah: Ad dayr Bridge (11), Garmat Ali Bridge (12), Alkhora River (13) and Abu Alkasib Coast (14) through the period between 24-27 May 2011. Littoral rotifers were sampled by filtering an approximate volume of 100 liters of waterusing a mesh size 50 µm plankton net. At the time of survey, some physical and chemical variables of the water body were measured by portable field instrument: water temperature (30-34ºC), dissolved oxygen (6.5-9 mg/l), salinity (0.7-4 ‰), pH (6.5-8.18) and nitrate (1.29-8.13mg/l). Identified rotifers belonged to thirty onespecies of eleven genera which by turn are related to eight families registered. Bdelloidea and three species were recorded from all the stations, these are, Brachionusplicatilis, Colurellaadriatica and Keratellaquadrata.

KEY WORDS: Rotifers, Biodiversity, Mesopotamia, Iraq.

Introduction:

Rotifers are microscopic aquatic animals occurring almost in all water bodies with diverse ecological conditions, their fascinating life traits together with the significant role in food chains have attracted people to explore their diversity and the dependence on ecological elements⁽¹⁾.Historically, many rotifer species have been considered to have worldwide distributions due to their high dispersal capabilities ⁽²⁾.Although most species of rotifers inhabit fresh water, some species also occur in brackish (estuarine) and marine habitats ⁽³⁾.

The southern part of Iraq received considerable attention in the field of environmental and biological studies during the seventies and beyond, as there were many of the scientific research of environmental and biological aspects of the Shatt Al-Arab River and its tributaries ⁽⁴⁾ and southern marshes⁽⁵⁾.In the context of articles published recently regarding rotiferan studies in the Southern region of Iraq^(6-8). The aim of the present study is to give basic primary information about the diversity and occurrence of the Rotifera from 14 unstudied aquatic environments at the period of the peak time.

MATERIALS AND METHODS:

This study was based on the materials collected, during a peak time of Rotifera from 24^th to 27^th May 2011 from 14 different localities (Figure 1). All stations were the running water environments ranged from deep to medium depth. The plankton samples were taken from each station by filtering 100 L of water through conical plankton net made up of bolting silk having a mesh size of 50 µm. The filtered plankton samples were preserved using 4% formaldehyde. Compound microscope was used for examination of the specimens. For identification of Rotifera, the most recent literatures were consulted (See⁴, for references). A Sedgewick-Rafter chamber was used to count the rotifers at 10x magnification with a light microscope. Rotifer community could be described from a qualitative and perspective using data expressed in terms of presence and absence of diagnosed species. The water temperature (Cº), Dissolved oxygen (mg/l), Salinity (‰), pH and nitrate were measured by YSI multi-meter model 2008. It was determined the coordinates of the selected stations using a GPS model 2003. Locations of sampling stations are illustrated on Table 1 and Figure 1.

Figure 1: Map of the study area with the locations of the 14 sampling stations at the South of Iraq.

Table 1: Locations of sampling sites at the South of Iraq.

Station number	Station location name	Directions	Governate
1	The five Shuhada Bridge	31°58'57.95"N 44°55'29.89"E	Al-Qadisiyyah
2	Corniche of Diwaniyah	31°59'33.84"N 44°54'23.21"E	Al-Qadisiyyah
3	Corniche of Samawah	31°19'8.71"N 45°16'53.91"E	Al-Muthanna
4	Al-Shuhada Bridge	31°18'49.86"N 45°17'46.50"E	Al-Muthanna
5	Euphrates River	31° 2'9.72"N 46°15'52.31"E	ThiQar
6	Alwafa canal	30°58'34.13"N 46°19'59.06"E	ThiQar
7	Al-Holindi Bridge	31° 4'26.18"N 46°16'53.41"E	ThiQar
8	Al-Shuhada Bridge	31°49'36.95"N 47° 9'0.76"E	Maysan
9	Nazim Al-Kahla River	31°50'45.25"N 47°10'3.89"E	Maysan
10	Nazim Al-Musharah River	31°51'20.35"N 47° 9'58.99"E	Maysan
11	Ad dayr Bridge	30°48'11.20"N  47°34'50.93"E	Basrah
12	Garmat Ali Bridge	30°34'26.90"N 47°44'41.18"E	Basrah
13	Alkhora River	30°30'32.26"N  47°51'0.46"E	Basrah
14	Abu Alkasib Coast	30°27'44.70"N  48° 0'6.50"E	Basrah

RESULTS:

The values of some ecological parameters are illustrated in the Table 2. The lowest value of water temperatures was 30°C at station 1 and the highest was 34°C at stations 6 and 14. Dissolved oxygen values ranged between 6 mg/l (the low value) at station 14 and 9 mg/l (the high value) at station 2. Maximum value of salinity was 4 ‰ at station 7 and the minimum was 0.7 ‰ in the station 6. The highest value of pH was 8.18 at stations12 and 14, while the lowest value was 6.5 at the station 4. Nitrate values ranged from 1.29 mg/l to 8.13 mg/l. The maximum value was recorded at station 4, while the minimum was in the station 11. The numbers of taxa recorded in each station were 17, 16, 13, 12             12, 11, 10, 20, 18, 18, 15, 16, 15 and 13 at stations 1-14 respectively. Identified rotifers belonged to thirty one species of eleven genera which by turn are related to eight families registered. Bdelloidea (which could not be identified to species level due to shrinkage) and three species were recorded from all the stations, these are, B. plicatilis, C. adriatica and K. quadrata.

Table 2: The values of some of the ecological parameters at study stations during 24-27 May 2011

Stations	Water temperature C°	Dissolved Oxygen mg/l	Salinity ‰	pH	NO3 mg/l
1	30	8.5	0.73	7.5	1.35
2	31	9	0.71	7.5	1.78
3	32	7.5	3.3	6.6	6.7
4	31.5	8	3.5	6.5	8.13
5	33	8	2	7	3.92
6	34	7	0.7	7.2	1.51
7	33	8	4	7.13	7.64
8	32	7	0.921	6.93	2.34
9	33	8.5	0.86	7.1	1.63
10	32	8	0.83	7.2	2.5
11	32	8	1.37	7.17	1.29
12	32	7	2.14	8.18	3.05
13	33	7	2.44	8.16	3.54
14	34	6.5	3.34	8.18	5.19

Table 3: Classification and occurrence of the rotifers which identified from studied stations at south of Iraq during 24-27 May 2011

Taxa	Stations
	1	2	3	4	5	6	7	8	9	10	11	12	13	14
Asplanchna sp.	+	+	—	—	—	+	+	+	—	—	—	—	—	—
Bdelloidea	+	+	+	+	+	+	+	+	+	+	+	+	+	+
Brachionusangularis	+	+	+	—	—	+	—	+	—	+	+	—	+	—
B.calycifloruscalyciflorus	—	—	—	—	+	+	—	—	—	—	+	—	—	—
B. plicatilis	+	+	+	+	+	+	+	+	+	+	+	+	+	+
B. quadridentatus	—	—	+	—	+	—	+	+	—	—	—	—	—	+
B. urceolaris	+	+	—	+	—	—	+	+	+	+	—	—	+	+
Brachionussp.	+	+	+	+	—	—	—	+	+	+	—	—	—	—
Colurellaadriatica	+	+	+	+	+	+	+	+	+	+	+	+	+	+
Euchlanisdilatata	—	—	+	—	—	—	+	—	—	+	—	—	—	—
Keratellacochlearis	—	—	+	—	—	—	—	+	+	—	—	—	—	—
K. quadrata	+	+	+	+	+	+	+	+	+	+	+	+	+	+
K. tropica	—	—	+	—	—	—	—	+	—	+	+	+	—	—
K. valga	—	—	—	—	—	—	+	—	—	—	—	—	—	—
Lecane bulla	+	+	—	—	—	—	—	—	+	—	—	+	+	—
L. closterocerca	—	—	—	+	+	+	—	+	+	+	+	+	—	—
L. hamata	—	+	—	—	—	—	—	—	—	—	—	—	—	—
L. luna	+	—	—	—	+	+	—	+	—	+	—	+	—	—
L. stenroosi	+	+	—	+	—	—	—	+	+	—	—	—	+	—
L. thalera	—	—	—	—	—	—	+	+	+	+	—	+	—	—
L. ungulata	+	—	+	—	—	+	—	—	+	—	+	—	+	+
Lecanesp.	+	+	+	—	—	—	—	+	+	—	—	+	—	—
Notholcaacuminata	+	+	—	—	—	—	—	+	—	—	+	+	—	—
N. squamula	—	+	—	—	+	+	—	—	+	+	+	+	+	+
Notholcasp.	—	—	—	+	—	—	—	—	—	—	—	+	—	—
Mytilinasp.	—	—	—	—	+	—	—	—	—	+	—	—	—	—
Polyarthradolichoptera	+	+	+	+	—	—	—	+	+	+	+	+	+	+
Synchaetalakowitziana	—	—	—	+	+	—	—	+	+	+	+	+	+	+
S. oblonga	+	+	—	+	+	—	—	—	+	+	—	+	+	+
Trichocercaporcellus	—	—	—	—	—	—	—	+	—	+	+	—	+	+
T. tetractis	+	—	—	—	—	—	—	—	+	—	+	—	+	+
Total number of taxa	17	16	13	12	12	11	10	20	18	18	15	16	15	13

Note : + means  present and  —  means  absent.

DISCUSSION:

The physio-chemical factors as temperature, salinity, pH and dissolved oxygen effect on the density and diversity of rotifers⁽⁹⁾. Rotifers able to withstand a wide range for temperature⁽¹⁰⁾. Some of the minor ecological changes may notaffect the rotifer community, as they are capable of acclimatization or modifying theirposition in the water column, but, certain other changes can affect the rotiferassemblages in the ecosystem. In adverse conditions, rotifers may produce resting eggsand, again, when environmental features become favourable, they can be hatched andamictic females capable of multiplying parthenogenetically, can be produced. Thetrophic status and rotifer assemblages of an ecosystem are very much related^(11).Salinity of the studied stations exhibited values more than those assignedfor fresh water but never exceeded 4.1‰ (Table 2).All species of rotifers were record in the present study (Table 3) which are commonly found in the southern Iraq⁽⁴⁾, it is apparent that Rotifera of the southern Iraq was dominated by ubiquitous and eurytrophic species that occur in fresh and saline waters with varied trophic states ^(4,6). B. plicatilis can live with a wide salinity range ⁽¹²⁾. Most of species in this study (Table 3) are cosmopolitans and euryhaline rotifers⁽¹³⁾. Synchaetais described as inhabiting marine or saline waters ⁽¹⁴⁾.pH values ranged between 6.5(station 4) to 8.18 (stations 12 and 14). Measured values showed that most studied stations water was alkaline. The rotifers prefer pH value in the range of 6.5 to 8.5⁽¹⁵⁾. A dissolved oxygen content of natural waters is one of the essential and limiting parameters for survival and existence of aquatic organisms. The minimum value was 6.5mg/l at station 14, and the maximum value was 9mg/l which was recorded in the station 2 (Table 2). In freshwater ecosystems, in aerobic conditions, the minimum dissolved oxygen for aquatic life may not be less than 5.0 mg/l.Rotifers can live in water with very low levels of dissolved oxygen, even in water containing just 2 mg/l of dissolved oxygen ⁽¹²⁾.There is a documented relationship between Rotifera and nitrate. The minimum value of nitrate was 1.29 mg/l at station 11, while the maximum was 8.13 mg/l at station 4. Solanki et al. ⁽¹⁶⁾, in their study on Pandu lake, found that the amounts of nitrates recorded in their study that the increased levels of nitrates prevented the growth of Rotifers and they concluded that the high concentration of nitrates resulted in the cessation of rotifers. In present study, bdelloids  were dominant at all stations because almost all them can carry a wide range of environmental conditions and are able to reproduce parthenogenesis and drought resistance ⁽¹⁷⁾.The dominant taxa were B. plicatilis, C. adriatica and K. quadrata (Table 3).This result agreed with most of the local studies ^(7,8). By looking the total number of taxa which was recorded at each station (Table 3), we found that there is a difference and diversity evident in the presence of the rotiferan taxa between stations. The highest number was 20 taxa at the station 8 (Al-Shuhada Bridge- Maysan) while the lowest number was 10 taxa in the station 7 (Al-Holindi Bridge-ThiQar) which is the paracentesis water. The reason for the difference to different environmental conditions between stations.

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Received on 02.07.2016       Modified on 17.07.2016

Accepted on 20.08.2016      ©A&V Publications All right reserved

Research J. Science and Tech. 2016; 8(3): 125-128.

DOI: 10.5958/2349-2988.2016.00016.4