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Epipsammic J.benthic Mar. Biol. Ass. India, of 49Kuwait (1) : 27Bay - 34, January - June 2007 27

Benthic microalgae on a sheltered intertidal in of the Northern Arabian

S.Y.Al-Mohanna, P.George and M.N.V.Subrahmanyam Department of Biological Sciences, Marine Science Programme, Kuwait University, P.O.Box 5969, Safat 13060, Kuwait. Email:[email protected] Abstract The sheltered intertidal of have scanty macrophytes but are rich in microflora. The dominant epipsammic of the microbial mats are . Dominant cyanobacterial forms include Microcoleus chthonoplastes, Oscillatoria nigro-viridis, and Lyngbya aestuarii. Algal (mea- sured as chlorophyll a concentrations) varied at the three study sites (A, S and K) reflecting their relative shelteredness. The mean annual chlorophyll a concentrations at sites A and S were 57 mg chl a m-2 and 315 mg chl a m-2 respectively. The most sheltered site K had a mean annual chlorophyll a concentration of 815 mg chl a m-2. Seasonal variation in the total epipsammic mat biomass contribution to the bay from the three sites was not observed reflecting its perennial in the sheltered Bay of Kuwait Bay. Keywords: Cyanobacteria, microflora, epipsammic, biomass, intertidal mudflats, Kuwait Bay

Introduction Intertidal zones are subjected to naturally occurring (Figs.1 & 2). It extends 48 km inland from the Arabian fluctuations in movement owing to tidal and wind Gulf, and is 40 km long and 25 km wide at the mouth. induced currents and waves. These have led to the for- Its bottom topography is generally flat and featureless. It mation of unique assemblages of flora and fauna as has shallow depths not exceeding 8m at its entrance resultants of horizontal gradient of shore exposure. In the (Khalaf, 1988). Surrounding the bay are intertidal mudflats, dynamically sheltered Kuwait Bay, microbial mats thrive up to 4 km wide at low . Tidal currents form the major on broad expanses of mudflats (Jones, 1986 a, b; Clayton, source of water circulation in the bay, and a weak counter- 1986) where water movement does not scour surfaces too clockwise circulation appears to prevail over most of the harshly. year (Figs. 3 & 4). The speed of the currents is highest Microbial mats or the lab-lab, formed of epipsammic at the entrance of the bay and decreases progressively (attached) and epipelic (motile) microalgal associations are towards its western portion, where it is usually -1 2 highly productive and their importance as a < 40cms Sulaibikhat Bay (approximately 70 km ) forms source of primary have received great atten- a highly sheltered tidal embayment that lies in the south- tion in temperate areas (Sundbäck and Jönsson, 1988; de western corner of Kuwait Bay (Figs. 1 & 3). For the Jonge and Colijn, 1994; MacIntyre et al., 1996; De Sousa present study, three sites (A, K and S) were selected at et al., 1998). Their role in food webs as source of fixed the intertidal mudflat of Sulaibikhat Bay (Fig. 2). Site ‘A’ carbon for many macrofauna has been studied (Herman located north of Sulaibikhat Bay, is part of a pristine salt et al., 1999; Al-Mohanna et al., 2004; Al-Zaidan et al., marsh tidal flat of Ashish Al- area. This site faces 2006). However, in comparison to epipelic microalgal eastward and hence receives direct solar radiation from associations, epipsammic associations have received very dawn to dusk. This shore is subjected to frequent strong little attention, particularly for the northern Arabian Gulf NE wind. On the other hand, site ‘K’ is located south region. This paper reports the composition, biomass and of Sulaibikhat Bay, adjacent to Port. This site spatial distribution pattern of epipsammic benthic has been subjected to infill at the landward edge, has few microalgae on a highly sheltered intertidal mudflat region man-made and characterized by the pres- in Kuwait Bay. ence of perpendicular seaward barriers constructed for commercial use. This site fails to receive direct solar Materials and methods radiation until the sun is up in the horizon (35-400) Study site: Kuwait Bay is a semi-estuarine area lo- due to its facing westward and surrounded from the east cated along the northern province of the Kuwaiti by anthropogenic alterations that include tall trees and

Journal of the Marine Biological Association of India (2007) 28 S. Y. Al-Mohanna and others

Fig.1. Location of Kuwait Bay Fig.2. Sulaibikat Bay is an embayment at the south-west of Kuwait Bay

Fig.3. Anti-clockwise currents during the tide cycle Fig.4. Sulaibikhat Bay - water movement - high tide (solid arrows) and ebb tide (broken arrows) buildings. Moreover, this shore is characterized by a mild epipsammic micro-flora. The epipsammic micro-flora, being prevailing wind. Site ‘S’ located opposite Sulaibikhat heavy, readily settled down, while the non-attached epipelic residential area, between site ‘A’ and site ‘K’, has also benthic and planktonic and detrital material remained been subjected to extensive infill at the landward edge. in suspension, and was decanted off. Sub-samples of As microbial mats are centered on the upper shore, the epipsammic microflora were prepared for pigment analy- horizontal region from mean highest high water down to sis, ash free dry weight determination and microscopy. 150m toward low waterline was marked as the survey The remaining sediment from each core was air-dried, and boundary at each site. 25 g of it was mixed with 250 ml of tap water containing 10 ml aqueous sodium hexametaphosphate (6.25 g/litre). Sample collection and preparation: Sediment samples This mixture was allowed to soak overnight. After break- were collected using a hand-held 5 cm diameter corer ing the soaked sediment with a glass rod, a 63-µm sieve inserted to a depth of 10 cm. Five random samples were was used to separate the fraction ( > 63 µm) collected from each site every month during March 2002 and mud fraction (particle = 63 µm). The sieve containing to February 2003. Samples were stored on ice and kept the sand fraction was dried in an oven at 100oC and in the dark until return to the laboratory, where they were cooled in a desiccator. The dried sand was weighed on frozen for later analysis.The top 3 mm of the collected a digital balance (Scientech SL 5200D) to the nearest sediment cores were carefully separated and repeatedly 0.01g. The percentage of sand and mud was calculated for swirled with filtered to remove the non- sediment analysis.

Journal of the Marine Biological Association of India (2007) Epipsammic benthic microalgae of Kuwait Bay 29

Temperature at mud surface was recorded using a 90% of the mat at the three sites were composed of digital thermocouple thermometer (Cole-Parmer Instru- Microcoleus chthonoplastes, Oscillatoria nigro-viridis, ment Co., Chicago). A mercury thermometer with an and Lyngbya aestuarii (Figs. 8-11). M. chthonoplastes accuracy of ±0.5oC was used to measure the dominated on the top areas of the where the of air and water in tide pools. and pH of water substrate was well drained at low tide and last covered by in tide pools were measured using a hand-held refracto- water during high tide (Fig. 8), while O. nigro-viridis and meter and digital pH meter (KAHLSICO, California) L. aestuarii prevailed in the lower adjacent moist areas of respectively. The above physical and chemical parameters littoral zone (Figs. 9 & 10). The less dominant Spirulina were recorded monthly during the sampling period. major (Fig. 11) was occasionally found at site K. Faecal Absorption spectrophotometry (Lorenzen, 1967) was pellets were frequently encountered on top of the micro- employed for pigment analysis, using the digital single bial mat, reflecting that the mat were heavily grazed upon cell mode UV/VIS spectrophotometer (BECKMAN DU (Fig. 12). ® 520). Total organic (AFDW) content of the sediment Pigment analysis: Mean annual biomass of mat (as was determined after oven drying at 80oC to constant measured by chlorophyll a) at site K differed significantly weight, followed by the loss on ignition at 500oC for 5 from sites A and S (ANOVA, F=25.54, P<0.001). The h in a muffle furnace (Gallenkamp Co.). Taxonomical mean annual concentration of chlorophyll a at site A and determination of the dominant mat components was car- -2 -2 ried out to lowest possible taxon, using Jones (1986a) S were 57 mg chl a m and 315 mg chl a m respec- and Al-Hasan and Jones (1989). An Olympus IX50 tively, whereas mean annual value of mat biomass at site -2 Inverted Microscope and a Nikon Microphot-FXA Mi- K was much higher (815 mg Chl a m ) in comparison croscope were used for this exercise. Sediment type at the to the other two sites. three sites was determined, based on mud/sand ratio The mudflats of Sulaibikhat Bay were rich in mat (Flemming, 2000). biomass throughout the year. There was no significant Results seasonal variation in total biomass of the three sites (ANOVA, F=1.26, P>0.05). However, site K which Physical and chemical parameters: From the profiles made highest contribution to the total biomass (815 mg of environmental parameters, it is evident that tempera- Chl a m-2), showed a significant seasonal variation tures (air, sediment surface and water pool) were always (ANOVA, F=3.87, P>0.003). This site experienced an higher at site A than at the other two sites (Table1). early summer bloom after which the standing stock of Salinity of tidal pool water was highest at site A and chlorophyll a decreased and remained low until Novem- lowest at site K. ber (Fig. 13). The standard errors are found to increase Sediment type: In sites A and K, the dominant sedi- with increasing chlorophyll a concentration at site K (Fig. ment constituent was sand (64% and 74% respectively). 13).A significant correlation existed between AFDW and Mud was the dominant fraction in site S (65%). As per chlorophyll a concentrations in the surface sediment mud/sand ratio, the sediment in sites A and K were (r2=0.636, P<0.01). Figure 14 shows the scatter plot of classified as ‘muddy sand’, while that in site S as ‘sandy mud’ (Table 2). Table 2. Sediment texture fraction at sites A, S and K Mat components: The epipsammic mat associations Sites Sand Mud were found to occur as dark green-blue layer at the fringe A 64% 35% of the eulittoral zone (Figs. 5 - 7). Filamentous S 35% 65% cyanobacteria formed the dominant components at the K 74% 26% three sites (Fig. 7). Few remained attached. 80-

Table1. Range of physical and chemical parameters during the period 2002-2003 Sites Air Mud surface Tide Tide pool Tide Temp. (°C) Temp. (°C) pool Temp. (°C) Salinity(ppt) pH A 19.0-42.6 16.9-37.7 17.3-36.8 53.43-75.83 7.00-8.87 S 17.0-36.7 14.4-31.1 13.4-31.1 47.67-68.00 7.00-8.68 K 17.0-36.0 16.2-31.9 14.8-31.0 41.33-51.67 7.02-9.53

Journal of the Marine Biological Association of India (2007) 30 S. Y. Al-Mohanna and others

Figs. (5) Extensive (cyanobacterial) mat -Microcoleus chthonoplastes (arrow), Oscillatoria nigro-viridis mat (arrowhead), aggregates of benthic diatoms on Oscillatoria (block arrow); (6) Intact sheet of Oscillatoria (arrow); (7) The mat formed of cyanobacterial filaments (arrow); (8) Single trichome of Microcoleus chthonoplastes surrounded by thick mucilage layer (arrows); (9) Several filaments of Oscillatoria; (10) Lyngbya aestuarii filaments; (11) Several filaments of Spirulina major; (12) Faecal pellets (arrows) on top of the algal mat.

Journal of the Marine Biological Association of India (2007) Epipsammic benthic microalgae of Kuwait Bay 31

Table 3. Spearman rank correlation coefficient between concentration of Chlorophyll a and environmen- tal parameters at sites A, S and K Chlorophyll a Parameters SiteA Site S Site K Mud-surface Temp. 0.448 (ns) -0.308 (ns) -0.713 * Tide pool salinity -0.547 (ns) -0.224 (ns) 0.768 * Tide pool pH -0.098 (ns) -0.224 (ns) -0.084 ns ns = not statistically significant. * = P<0.01 (r2=0.768, P<0.01). No significant correlation was found between pH and chlorophyll a even at this site. Discussion Mean annual microalgae (cyanobacteria) biomass was highest at site K (Fig. 13), reflecting the relatively more sheltered nature of this area of Sulaibikhat Bay. This site -2 Fig. 13. Chlorophyll a concentrations (mg Chl a m ± SE) of mudflat is highly wave-protected when compared to at site A (o), site S (∆), and site K ( ) from March the other sites. This is due to the construction of perpen- 2002 to February 2003 dicular seaward barriers (jetties or groins) for commercial use. Such a shore alteration along site K has interfered with the natural processes, affecting the general water circulation, diminishing the velocity of water (wave fetch), limiting the rip currents and interfering with the long shore drift during rise of tide. The increase in the degree of shore exposure from sites K to A through S is re- flected in the biomass recorded at these sites. Wave- generated turbulence and shear stress may cause re-sus- pension of surface sediments and their associated microphytobenthos and, consequently, lower the microalgae biomass (de Jonge and van Beusekom, 1995). During the present investigations, it was realized that increasing ex- posure carries an increased risk of dislodgement and physical damage, limiting the range and of at the three sites of Sulaibikhat Bay. Though Fig. 14. Scatter plot showing the relationship between site A had the same sediment type as at K (muddy sand), AFDW (g organic matter m-2) and chlorophyll a con- the former showed much less biomass and abundance of centration (mg Chl a m-2) in sediment samples from the the mat than the latter. It appeared that at site A, the three sites. Spearman rank correlation coefficient, natural exposure plays a role in limiting/restricting r2=0.636, P<0.01 cyanobacterial colonization along the shore of Sulaibikhat Bay. Indeed, site A is a pristine shore that is much exposed to prevailing NE winds, relatively fast longshore these two variables. Spearman rank correlation coeffi- currents and long-shore drifts. cients (r2) between concentrations of chlorophyll a and a range of physico-chemical parameters at the three sites Epipsammic mat associations usually occur as a band indicated that there was no significant correlation between of microbial bio-film along the fringe of the eulittoral zone chlorophyll a and mud surface temperature, salinity and of mudflats (Figs. 5 & 6). The sediment (in top of littoral pH (tide pool) at site A and S (Table 3). However, zone) is coarse and less moist, while the adjacent lower significant correlations were found at site K: (i) mud regions are characterized by a mixture of mud and sand. surface temperature (r2=-0.713, P<0.01) and (ii) salinity Krumbein et al. (1994) reported that cyanobacteria prefer

Journal of the Marine Biological Association of India (2007) 32 S. Y. Al-Mohanna and others coarse sediments for colonization. During the present euglenoids in summer, then back to diatoms in autumn. study, it was observed that the filaments of cyanobacteria In the present study, a negative correlation (r2=-0.713, formed intertwined network of mat, binding the sand P<0.01) between chlorophyll a and mud surface tempera- particles (Fig. 7), while diatoms prefer the finer ture (16.2 oC – 31.9 oC) suggests that extremely high with lesser interstitial space to avoid hampering their have a negative impact on the growth of migration. This agreed with the findings of Watermann et cyanobacteria. al. (1999) who stated that cyanobacteria favour coarser Salinity values were always highest at site A and sediments while diatoms dominate on mud with small lowest at K. Exposure at low tide opens the shore and its grains. In this study M. chthonoplastes is found to substratum to high air temperatures resulting in a high dominate the uppermost sandy region of the that is characterized by relatively large sand grains evaporation rate and the perfusion of the sediments with and covered by water during high tide. The filaments of water of high salt content. Indeed white crust of salt was this cyanobacterium are enveloped by thick mucilage layer always encountered on the sediment surface of sites A (Fig. 8) that helps to protect its trichomes to overcome the and S, particularly during the neap . Clayton (1986) long periods of exposure to atmospheric air and desicca- stated that salinity gradient across the mat and alternate tion. O. nigro-viridis and L. aestuarii, on the other hand, saturation and desiccation of it produce changes in the occur as single filaments surrounded by thin mucilage sediment surface morphology leading to zoning in the layer and tend to prefer relatively moister and finer sub- microalgal mat itself. A correlation between chlorophyll a strates where mud and sand mix. The ability of microbial and salinity was seen only at site K where the sediment biofilms to influence the behaviour of intertidal sediments was relatively more moisture laden and no white crust of is now recognized (Grant and Gust, 1987; Paterson et al., salt was encountered. It is apparent that other factors such 1990). The mats dominated by cyanobacterial cells and as the duration of and submergence, influence extracellular polymeric secretions effectively stabilize the of weather and evaporation, indirectly affect temperature substrate (Watermann et al., 1999). It may, therefore, be and salinity, thus determining the abundance, distribution possible to relate the degree of biostabilization to biomass and biomass of cyanobacteria in situ. as well as the physical properties of the sediment (Pater- There is no significant seasonal variation in total bio- son et al., 1990). mass of microbial mats for the three sites of Sulaibikhat Watermann et al. (1999) reported that beside grain Bay. A similar pattern in the seasonal variation of size, temperature is also an important limiting factor for microphytobenthos biomass has been reported by Brotas the microbial mat growth. The intertidal mudflats fre- et al.(1995); De Sousa et al.(1998) in Tagrus Eastuary quently experience a much wider range of temperature () and Santos (Brazil) respectively. How- than the other . This is due, in part, to their ever, an initial summer bloom was observed at site K relatively large surface area/volume ratios, thus allowing because at very favourable temperatures, cyanobacteria heating and cooling more rapidly under prevailing atmo- appeared in mud as patches amid the diatoms. Watermann spheric conditions (Boaden and Seed, 1996). This is true et al. (1999) concluded from laboratory experiments that for site A where sediment surface is highly exposed to at high temperatures, grain size may have less control on various fluctuations in atmospheric and environmental the growth behaviour of cyanobacteria, and temperature conditions including weathering (wind), degree of expo- effects apparently over-rule the substrate factor. The sure to sun and wave actions compared with other sites. characteristic patterns of laminated biomass intertwined Such factors have led to low values of abundance and with sand grains is lacking on mud. Here, the filamentous restricted the distribution of microbial mat at this site. A cyanobacteria only build surficial biofilms (Paterson, 1994). correlation between chlorophyll a and temperature was Microphytobenthos communities are known to present seen only at site K, which was most sheltered and where heterogeneous distributions in space – patchiness (Brotas temperature fluctuation was less pronounced. Laboratory and Plante-Cuny, 1998). The large standard error com- studies by Watermann et al. (1999) have proved that a puted for site K represents an irregular or patchy distri- high temperature range (150C -250C) favours cyanobacteria bution of chlorophyll a due, in part, to blooming of growth, with highest biomass at 150C on sand, while microbial mats. Thus, patchiness increases with increase diatoms dominate at a low temperature range (100C - in biomass. Declines in algal biomass could be due to a 150C). Barranguet et al. (1997) have observed that, in the range of factors, such as nutrient limitation, consumption uniformly sandy NE region of Molenplaat, there is a by grazers, desiccation or dislocation by adverse weather succession from diatoms in to cyanobacteria and conditions. Cyanobacteria were found to be resistant to

Journal of the Marine Biological Association of India (2007) Epipsammic benthic microalgae of Kuwait Bay 33 nutrient stress (Villbrandt et al., 1990). It has been well EXZ0011, Environment Public Authority (EPA), established that grazing by micro-, meio- and macrofauna Kuwait, 407 pp. (Fig. 12) may affect microphytobenthos biomass, but Al-Zaidan, A. S. Y., D. A. Jones, S. Y. Al-Mohanna and most studies have been limited to a single or few con- R. Meakins. 2003. Endemic macrofauna of Sulaibikhat sumer and have been performed in laboratory or Bay and mudflat habitats, Kuwait: status experimental systems rather than in situ (Miller et al., and need for conservation. J. Arid Environ., 54(1): 1996; Al-Zaidan et al., 2003; Al-Mohanna et al., 2004). 115-124. Montagna (1984) and Morrisey (1988) suggested desic- ——————, H. Kennedy, D. A. Jones and S. Y. Al- cation and grazing to be possible causes for summer Mohanna. 2006. Role of microbial mats in Sulaibikhat 13 declines in mat biomass. The absence of seasonal varia- Bay (Kuwait) mudflat food webs: evidence from d C tion in the total epipsammic mat biomass from the three analysis. Mar. Ecol. Prog. Ser., 308: 27-36. sites reflects their perennial nature in the Bay which is Barranguet, C., P. M. J. Herman and J. J. Sink. 1997. barren of macroalgal life. It is reasonable, therefore, to Microphytobenthos biomass and compo- suggest that the microbial mats (lab-lab) at the mudflats sition studied by pigment biomarkers: importance and of Sulaibikhat Bay/Kuwait Bay form an important and/or fate in the carbon cycle of a tidal flat. J. Res., 38: main source of carbon to tidal flat’s inhabitants. 59-70. In the Arabian Gulf, the ecological importance of Boaden, P. J. S. and R. Seed. 1996. An Introduction to cyanobacteria in the intertidal mudflats was recognized for Coastal . Blackie Academic & Professional Pbl., UK, 218 pp. the first time after the 1991 and subsequent massive oil spill along the eastern of Saudi Arabia. Brotas, V., T. Cabrita, A. Portugal, J. Serodio and F. These impacted-oil tar shores experienced extensive growth Catarino. 1995. Spatio-temporal distribution of of cyanobacterial mats that allowed re-colonization of microphytobenthic biomass in tidal flats of Tagus Estuary (Portugal). Hydrobiologia, 300/301: 93-104. macrofauna in these areas after being wiped out com- pletely by the oil spill (Hoffman, 1996; Jones et al., Brotas, V. and M. R. Plante-Cuny. 1998. Spatial and 1996). The recolonized macrofauna were reported to graze temporal patterns of microphytobenthic taxa of es- on cyanobacterial mats as source of nutrition, thereby tuarine tidal flats in Tagrus Estuary (Portugal) using reducing their biomass to a narrow band on the top of the pigment analysis by HPLC. Mar. Ecol. Prog. Ser., 171: 43-57. shores (Jones et al., 1996). Despite mudflats’ unique entity and ecological importance, many coastal planners Clayton, D. A. 1986. Ecology of mudflats with particular and engineers frequently look at them as un-interesting reference to those of the northern Arabian Gulf. In: coastal habitats or wastelands and subject them to several Halwagy, R., Clayton, D. and Behbehani, M. (Eds.). alterations associated with urbanization and industrializa- Marine Environment and Pollution. Alden Press, Oxford, p.83-96. tion. Unplanned actions could destroy such habitats and their primary producers (microbial mats) beyond repair, De Jonge, V. N. and F. Colijn. 1994. Dynamics of which can result in total loss of that sustains microphytobenthos biomass in the Ems estuary. Mar. local commercial fisheries. Ecol. Prog. Ser., 104: 185-196. —————. and J. E. E. Van Beusekom. 1995. Wind- and Acknowledgements tide-induced re-suspension of sediment and micro- The authors wish to thank Prof. Stephen Dadzie and phytobenthos in the Ems Estuary. Limnol. Oceanogr., Dr. Amani S. Al-Zaidan of Department of Biological 40: 766-778. Sciences, Kuwait University for their critical comments De Sousa, E. C. P. M., L. R. Tommasi and C. J. David. concerning the manuscript. They also wish to acknowl- 1998. Microphytobenthic , biom- edge the assistance of the personnel of Microbial Project ass, nutrients and pollutants of Satos Estuary, Sao No. EXZ0011, Environment Public Authority, Kuwait. Paulo, Brazil. Braz. Arch. Biol. Technol., 41(1): 27- 36. References Flemming, B. W. 2000. A revised textural classification of Al-Hasan, R. H. and W. E. Jones. 1989. Marine algal flora gravel-free muddy sediments on the basis of ternary and sea grass of the coast of Kuwait. J. Univ. Kuwait diagrams. Cont. Shelf. Res., 20: 1125-1137. (Sci.), 16: 289-339. Grant, J.and G. Gust.1987. Prediction of coastal sediment Al-Mohanna, S. Y., D. A. Jones, M. N. V. Subrahmanyam stability from photopigment content from mats of and P. George. 2004. The role of microbial mats in purple sulphur . Nature, London, 330: 244- the Arabian Gulf . Final report of project 246.

Journal of the Marine Biological Association of India (2007) 34 S. Y. Al-Mohanna and others

Herman, P. M. J., J. J. Middelburg, J. Van De Koppel and tats: I. Distribution, abundance and primary produc- C. H. R. Heip. 1999. The ecology of estuarine tion. , 19: 186-201 . Adv. Ecol. Res., 29: 195-240. Miller, D. C., R. J. Geider, and H. L. Macintyre. 1996. Hoffman, L. 1996. Recolonization of the intertidal flats by Microphytobenthos: The ecological role of the secret microbial mats after the Gulf War Oil Spill. In: Krupp garden of unvegetated, shallow-water : F., A.H. Abuzinada and I.A. Nader (Eds.) A Marine Role in sediment statbility and shallow-water food Wildlife Sanctuary for the Arabian Gulf: Environmen- webs. ibid., 19: 202-212. tal Research and Conservation Following the 1991 Gulf War Oil Spill. NCWCD, Riyadh and Senckenberg Montagna, P. A. 1984. In situ measurement of meiobenthic Research Institute, Frankfurt, p. 96-115. grazing rates on sediment bacteria and edaphic dia- toms. Mar. Ecol. Prog. Ser., 18:119-130. Jones, D. A. 1986a. A Field Guide to the seashore of Morrisey, D. J. 1988. Differences in effects of grazing by Kuwait and the Arabian Gulf. Kuwait University Press, deposit feeders Hydrobia ulvae (Pennant) (Gastropoda: Kuwait, 192 pp. Prosobranchia) and Corophium arenarium Crawford ————— 1986b. Ecology of the rocky and sandy shores (Amphipoda) on sediment microalgal populations:II. of Kuwait. In: Halwagy, R., Clayton, D.A, and Quantative Effects. J. Exp. Mar. Biol. & Ecol., 118: Behbehani, M (Eds.) Marine Environment and Pollu- 43-53. tion. Alden Press, UK, p. 69-82. Paterson, D. M. 1994. Microbial mediataion of sediment —————., I. Watt, J. Plaza and T. D. Woodhouse. 1996. structure and behaviour, In: Stal. L J. and Caumette. Natural recovery of the intertidal biota within the P (Eds.) NATO ASI Series, Vol.G35, Micobial Mats, proposed marine and wildlife sanctuary for the Springer, Berlin, p. 97-109. Arabian Gulf (Saudi Arabia) after the 1991 Gulf War —————., R. M. Crawford and C. Little. 1990. Sub- oil spill. In: Krupp, F., Abuzinada, A. and Nader. I aerial exposure and changes in the stability of inter- (Eds.) A Marine Wildlife Sanctuary for the Arabian tidal sediments. Estuar. Coast. Shelf Sci., 215: 251- Gulf: Environmental Research and Conservation Fol- 260. lowing the 1991 Gulf War Oil Spill. NCWCD, Riyadh and Senckenberg Res Inst, Frankfurt, p.138-158. Sundbäck, K. and B. Jönsson. 1988. Microphytobenthic Khalaf, I. 1988. Quaternary calcareous hard rocks and productivity and biomass in sublittoral sediments of a associated sediments in the intertidal and offshore stratified bay, southeast Kattegat. J. Exp. Mar. Biol. zone of Kuwait. Mar. Geol., 30: 1-27. Ecol., 122: 63-81. Villbrandt, M., L. J. Stal and W. E. Krumbein. 1990. Krumbein, W. E., D. M. Paterson and L. J. Stal. 1994. Interactions between and oxygenic Biostabilization of sediments. Bibliotheks-und in a marine cyanobacterial mat. FEMS Informationssystem der Universitat Oldenburg, Ger- Microbial Ecol., 74: 59-72. many, 526pp. Lorenzen, C. J. 1967. Determination of chlorophyll and Watermann, F., H. Hillebrand, G. Gerdes, W. E. Krumbein phaeo-pigments: spectrophotometric equations. Limnol. and U. Sommer 1999. Composition between benthic Oceanogr., 12: 343-346. cyanobacteria and diatoms as influenced by different grain sizes and temperatures. Mar. Ecol. Prog. Ser., Macintyre, H. L., R. J. Gelder and D. C. Miller. 1996. 187: 77-87. Microphytobenthos: the ecological role of the ‘secret Received: 14 May 2007 garden’ of un-vegetated, shallow-water marine habi- Accepted: 31 August 2007

Journal of the Marine Biological Association of India (2007)