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The aim of this study implied comparing the morphology of periodontal tissues in patients with diabetes mellitus following the results of surgical intervention due to inflammatory and destructive periodontal diseases. We used an erbium laser and a standard surgical method. For this, histological samples obtained from 34 patients were examined. The biopsy samples in Group 1 were studied prior to the surgical treatment of inflammatory and destructive periodontal diseases. Group 2 included histological samples of patients following surgeries employing conventional surgical techniques. Group 3 included gum biopsies obtained after surgical interventions performed with the erbium laser. The research outcomes revealed that when performed in patients with diabetes mellitus complicated with diabetic microangiopathy of the gingival mucosa, surgical curettage or a standard surgical operation with a scalpel did not lead to any significant decrease in the chronic inflammatory process. The morphological picture of the gum soft tissues in patients with Type I and II diabetes mellitus, 3 months after the treatment with the erbium laser as a cutting tool, matched the usual structure of the mucous membrane with no obvious signs of inflammation.

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

Kuwait, which is located in the northwestern Arabian Gulf, has experienced several incidences of marine life mortality during the past two decades. Mortalities included pelagic and benthic fish, Sea Cucumbers and Mollusks including pearl oysters. Most of the mortalities occurred in Kuwait Bay, which is shallow and semi-enclosed. The Bay encompasses Sulaibikhat Bay, whose coastal waters are nutrient-rich and eutrophicated due to sewage discharge into its waters. Other mortalities were reported outside Kuwait Bay, especially in marinas and southern waters of Kuwait. Kuwait’s marine environment has been increasingly affected by harmful algal blooms, which increased by frequency and severity. Other Gulf countries experienced serious mortality incidences as well. Different causes were responsible for the different marine mortalities in Kuwait and the region, including untreated sewage input, eutrophication, bacterial infection, algal blooms, hypoxic conditions, pollution, and dredging. The above mortalities impacted the economy, and affected aquaculture activities, the fishing operations, coastal tourism, damaged coral reefs, and forced the closure of desalination plants. This study summarizes the different mortality incidents that occurred in the northwestern Arabian Gulf during the period of 1999 to 2019 and their possible causes. Efforts, taken by Kuwait to improve the environmental conditions of the degraded coastal area of Kuwait Bay, include for example, the designation of a marine protected area in southern Kuwait Bay that would ensure the continued production of ecological services of the protected Bay area.

This chapter summarizes the results of research studies, which addressed the peculiarity of the estuarine and northern Arabian Gulf marine environment and the influence of the Shatt Al-Arab River and its associated marshes on the oceanography and biodiversity of the northern Gulf. The findings of the studies indicated that the northern waters of Kuwait, which are impacted by the Shatt Al-Arab River discharge, displayed lower salinity, higher nitrate concentration, higher chlorophyll-a, and higher sedimentation. The biodiversity of the northern waters of the Gulf also was significantly distinguished from the adjacent area away from the influence of the river flow. Discharge of the Shatt Al-Arab is considered to be a dominating driver of the northern Gulf’s ecology and largely responsible for the primary and secondary productivity of Kuwait’s waters. Long-term reduction in river discharge due to man-made alterations (damming and diversion of rivers) impacted the oceanographic characteristics of Kuwait’s waters with implication to fisheries resources. Management of Shatt Al-Arab River discharge into the Gulf requires cooperation among the riparian countries and downstream countries like Kuwait to preserve the productivity, biodiversity, and uniqueness of the northern Gulf ecosystems. Long-term monitoring and assessment as well as joint research programs involving scientists from the three concerned countries, Kuwait, Iraq, and Iran, are needed.

To examine whether a country-wide COVID-19 lockdown affected phytoplankton development, variability of chlorophyll-a concentrations in the north-western Arabian/Persian Gulf (Kuwait Bay) was investigated using remote sensing instruments Sentinel OLCI between 2018 and 2020 and compared to available in situ collected data. Satellite-retrieved chlorophyll concentrations considerably increased in inshore waters of Kuwait Bay, 1-2 months following the initiation of the 24/7 curfew. The extremely high concentrations of dissolved inorganic nutrients, especially ammonia, and coincided phytoplankton bloom were revealed in June-July 2020 by opportunity field sampling, supporting the satellite-derived bloom detection. Remote sensing operational monitoring with high spatial resolution sensors provides an exceptional opportunity for emergency analysis and decision making in conditions of natural or anthropogenic crises, which forces the development of regional remote sensing algorithms for the shallow marine environment of the Gulf.

In the Arabian Gulf, mangroves play a particularly important role in maintaining biodiversity. Water and intertidal sediments were collected from eight sampling locations in April 2017 to assess the environmental status of the mangrove forest in the Khor al Beida, Umm Al Quwain, which is one of the largest natural mangrove forests in the United Arab Emirates (UAE). Khor al Beida is also a breeding ground for the largest Gulf colony of a regionally endemic Socotra cormorant. Total metal concentrations of water and sediments were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and ranged between 0.001&ndash, 2.873 mg/L and 0.08&ndash, 12683.02 mg/kg, respectively. Most metals were within permissible levels, except for copper, iron, aluminum, zinc, and nickel. Hazard Quotient calculations showed low risk to the ecosystem in relation to the presence of heavy metals, with the exception of zinc. Fifty-three diatom species of pennate benthic forms were identified in the intertidal sediments. For the first time in the UAE, diatom composition and diatom diversity values were quantitatively estimated in the surface sediments and a short sediment core. Overall, the assessment suggests that the mangrove forest is currently undisturbed and shows very little anthropogenic impact, yet, protection and conservation efforts are necessary in order to maintain its current status.

Spatial distribution of the chlorophyll-a and phytoplankton community composition related to different water masses were studied during regional cruise in February-March 2006 across the Arabian/Persian Gulf and the Sea of Oman, the marginal seas of the Western Indian Ocean.Chlorophyll-a concentrations were measured using in vitro method with fluorescence detection and also were assessed as in vivo fluorescence measured by submersible fluorometer. Nearly four hundred species of phytoplankton were enumerated and identified using microscopy in the samples collected at the same stations.High phytoplankton abundance was associated with diatom-dominated phytoplankton blooms in the central and northwestern part of the Gulf, in the Strait of Hormuz and in the Sea of Oman. The average concentration of in vitro measured surface chlorophyll-a in the studied area was 2.5 mg/m3, with the maximum over 9 mg/m3. The relationships between the concentrations of satellite remotely sensed chlorophyll and in vitro measured chlorophyll-a were found to be mostly in good agreement. The highest concentrations of the surface chlorophyll (> 4 mg/m3) were observed in the areas where diatom-dominated blooms were identified. It was revealed a significant relationship between the phytoplankton composition and water masses indexed by salinity.The main significance of this study is in the first data set of in vitro measured precise chlorophyll-a concentrations that were obtained along with phytoplankton abundance and taxonomic diversity from the entire region of the Arabian/Persian Gulf and the Sea of Oman. This data set can be used for remote sensing measurements validation and as a baseline for future studies of the biological productivity changes in the Western Indian Ocean.

The spatial distribution of the phytoplankton (diversity, composition, and cell abundance) was described in relation to local environmental conditions across the Arabian Gulf, the Strait of Hormuz, and the Sea of Oman based on data of ROPME cruise of winter 2006. The 376 phytoplankton taxa identified in these waters represented a diverse composition of species with a prevalence of dinoflagellates and diatoms. Three peaks in the phytoplankton abundance were recorded throughout the studied area associated with diatom-dominated phytoplankton blooms in the central and northwestern part of the Arabian Gulf and in the Sea of Oman and the adjacent waters. The studied area was divided into three main regions by cluster analysis based on differences in the phytoplankton composition and concentration. The Sea of Oman and the Strait of Hormuz were occupied by highly abundant, strongly diatom-dominated phytoplankton assemblage. The Arabian Gulf was divided into two main regions along a diagonal northwest-southeast axis, with rather diatom-dominated phytoplankton assemblage off the south and along the Iranian coast but with flagellate-dominated phytoplankton of the north and along the Arabian coast. The distance-based linear modeling revealed a significant relationship between the phytoplankton composition and water masses as indexed by salinity. Our results demonstrated that abundance and composition of winter phytoplankton were related to water circulation pattern in the Arabian Gulf and the Sea of Oman.

Kuwait's marine area, located at the far north-western corner of the Arabian/Persian Gulf, is under significant and diverse anthropogenic effects, which are exacerbated by climatic changes. Microalgal blooms occur in Kuwait's waters year round and are caused by proliferation of microalgae, cyanobacteria, and photosynthetic ciliates. The diverse assemblage of potentially toxic diatoms and dinoflagellates known elsewhere to cause syndromes of human poisoning was revealed in Kuwait's marine environment. A wide range of potentially harmful microalgae that can be associated with mortality of marine biota, including known ichthyotoxic dinoflagellates, raphidophycean and haptophyte flagellates, were observed routinely in Kuwait's waters. The chronological overview of recorded algal bloom events indicates that Kuwait's marine environment is increasingly affected by harmful algal blooms (HABs). Both toxic and high biomass blooms were associated with fish mortality in Kuwait's coastal waters. Most of algal blooms occurred during the warm periods in spring and autumn, whereas fish mortality events linked to high biomass blooms mainly during the hot summer season. Long-term variability in occurrence and composition of phytoplankton blooms in Kuwait's waters was largely governed by alteration of dissolved inorganic nitrogen to phosphorus stoichiometric ratio.

The Arabian/Persian Gulf [hereafter the Gulf (Sheppard et al. (Mar Pollut Bull 60:13–38, 2010) mentioned that fourteen historical variants of the name of the Arabian/Persian Gulf are known. Here the name ‘Gulf’ is used, as is the case in several preceding scientific papers.)] is a marginal sea of the Indian Ocean connected with the Gulf of Oman through the Strait of Hormuz. Remote sensing approaches to the studies of phytoplankton biomass variability within this very productive and hydrographically and optically complex area are reviewed and analyzed. The remote-sensing reflectance of the Gulf surface is significantly affected by bottom reflection due to the Gulf’s shallowness. Another crucial factor is the deposition of aeolian dust transported through the atmosphere from the adjacent deserts. Spatial and temporal variability in phytoplankton biomass estimated as remotely sensed chlorophyll concentrations together with physical factors are analyzed with a special emphasis on high biomass and toxic phytoplankton blooms.

A small Prorocentrum species was found during a pilot taxonomic survey of marine benthic dinoflagellates in the northwestern Arabian Sea, Oman. Based on the study of cells from natural samples and laboratory cultures using light and scanning electron microscopy, this taxon is attributed to the little-known Prorocentrum sipadanense, recorded so far only from East Malaysia. The description of this species has been emended to include details of internal cell structure, composition of its periflagellar area and intraspecific variability in size, shape and pore pattern. Round to oval or ovoid cells of P. sipadanese are surrounded by a prominent marginal ridge and are 17.9–23.9 µm long and 15.0–19.8 µm wide, with a foveate to reticulate thecal plate surface and asymmetric and scarce pore pattern. The small, V-shaped periflagellar area is composed of nine platelets. Cells possess two golden-brown chloroplasts with a central starch-sheathed pyrenoid and small posterior nucleus. In addition, the phylogenetic position of this taxon in Prorocentrum was revealed for the first time based on SSU and LSU rDNA data. The presence of P. sipadanense among epiphytic dinoflagellates from the Omani coast constitutes its first report from the Indian Ocean.

A new thecate, photosynthetic, sand-dwelling marine dinoflagellate, Laciniporus arabicus gen. et sp. nov., is described from the subtidal sediments of the Omani coast in the Arabian Sea, northern Indian Ocean, based on detailed morphological and molecular data. Cells of L. arabicus are small (16.2-30.1 μm long and 13.1-23.2 μm wide), dorsoventrally compressed, with a small apical flap-shaped projection pointing to the left. The thecal plate pattern is distinguished by minute first precingular plate and sulcus, which extends into the epitheca, with large anterior and right sulcal plates. The Kofoidian thecal tabulation is Po, X, 4', 2a, 7'', 6c, 6s, 5''', 2''''. Morphologically, the revealed plate pattern has an affinity to the Peridiniales, and LSU rDNA based phylogenetic analyses placed L. arabicus within the Thoracosphaeraceae, close to calcareous-cyst producing scrippsielloids, predatory pfiesteriaceans, and photosynthetic freshwater peridinioids Chimonodinium lomnickii and Apocalathium spp. However, the thecal plate arrangement of L. arabicus differs noticeably from any currently described dinoflagellates, and the species stands out from closely related taxa by extensive differences in physiology and ecology.

A new photosynthetic, sand-dwelling marine dinoflagellate, Ailadinium reticulatum gen. et sp. nov., is described from the Jordanian coast in the Gulf of Aqaba, northern Red Sea, based on detailed morphological and molecular data. A. reticulatum is a large (53–61 μm long and 38–48 μm wide), dorsoventrally compressed species, with the epitheca smaller than the hypotheca. The theca of this new species is thick and peculiarly ornamented with round to polygonal depressions forming a foveate-reticulate thecal surface structure. The Kofoidian thecal tabulation is APC (Po, cp), 4′, 2a, 6′′, 6c, 4s, 6′′′, 1p, 1′′′′ or alternatively it can be interpreted as APC, 4′, 2a, 6′′, 6c, 4s, 6′′′, 2′′′′. The plate pattern of A. reticulatum is noticeably different from described dinoflagellate genera. Phylogenetic analyses based on the SSU and LSU rDNA genes did not show any supported affinities with currently known thecate dinoflagellates.

The composition and distribution of the main unicellular eukaryotic groups (diatom algae, ciliates, dinoflagellates (DF), other phototrophic (PF) and heterotrophic flagellates (HF)) were investigated in sandy sediments at five stations allocated across the tidal sheltered beach of the White Sea. Overall, 75 diatoms, 98 ciliates, 16 DF, 3 PF and 34 HF species were identified; some are new records for the White Sea. Common species for each group are illustrated. Diatoms and ciliates showed high alpha-diversity (species richness per sample), whereas flagellates were characterized by high beta-diversity (species turnover across the intertidal flat). Each group demonstrated its own spatial pattern that was best matched with its own subset of abiotic variables, reflecting group-specific responses to environmental gradients. Species richness increased from the upper intertidal zone seaward for ciliates but decreased for HF, whereas autotrophs showed a relatively uniform pattern with a slight peak at the mid-intertidal zone. Across the littoral zone, all groups showed distinct compositional changes; however, the position of the boundary between “upper” and “lower” intertidal communities varied among groups. Most of the species found at Ryazhkov Island are known from many other regions worldwide, indicating a wide geographic distribution of microbial eukaryotic species.

Background The occurrence of a small brackish water bloom-forming dinoflagellate belonging to the genus Peridiniopsis is reported for the first time from the Shatt Al-Arab River in Iraq. Based on the study of cell morphology, this taxon was attributed to the recently described Peridiniopsis minima, recorded so far only from the Jiulongjiang River, China. Results The description of P. minima was extended to include some previously unreported details of the thecal surface, apical pore complex, and sulcus structure using light and scanning electron microscopy. Cells of this species from Iraq were oval to rhombic in shape and slightly dorso-ventrally compressed, with distinct red eyespot and endosymbiont nucleus. Cells were covered by a thin theca with the Kofoidian plate formula Po, X, 3′, 1a, 6″, 5c, 5 s, 5′′′, 2′′′′. Complementing the original description of the species, five plates were discerned in the composition of the sulcal area, and the presence of small median sulcal plate was confirmed. Conclusion The finding of P. minima in the waters of Shatt Al-Arab River represents a new addition to the Iraqi aquatic microflora. Our observations of this dinoflagellate in brackish waters of the Shatt Al-Arab River system extend the known range of salinity tolerance for this species.

Saburova M., Chomerat N. and Hoppenrath M. 2012. Morphology and SSU rDNA phylogeny of Durinskia agilis (Kofoid & Swezy) comb. nov. (Peridiniales, Dinophyceae), a thecate, marine, sand-dwelling dinoflagellate formerly classified within Gymnodinium. Phycologia 51: 287–302. DOI: 10.2216/10-22.1 A new taxon of the dinoflagellate genus Durinskia Carty & Cox, previously considered a member of Gymnodinium Stein, is characterized from intertidal sand flats of Kuwait, in the northwestern part of the Arabian (Persian) Gulf. The taxonomic status of this dinoflagellate was reassessed on the basis of morphological and molecular data. Light and electron microscopical examinations revealed a previously undescribed delicate theca. The thecal plate formula is Po, x, 4′, 2a, 7″, 5c, 6s, 5‴, 2‴′. Based on the cell shape, thecal plate arrangement, the presence of a slit-like apical pore and an eyespot, as well as on SSU rDNA sequence data, the organism is reclassified as Durinskia agilis (Kofoid & Swezy) Saburova, Chomerat &...

A new benthic dinoflagellate species, Prorocentrum bimaculatum sp. nov., is studied from Kuwait's marine sediments, based on detailed morphological and molecular data. Cells are large, oblong oval in shape. They are 49.9-55.3 μm long and 38.4-43.2 μm wide. The ornamentation of this new species is peculiar, and characterized by smooth valves with large pores (0.32-0.50 μm) scattered on their surface, except in two circular patches of ∼15 μm in diameter, devoid of ornamentation and located on both sides of the valve centers. The periflagellar area is widely triangular, located in a moderate excavation of the right valve, and comprises nine platelets. The intercalary band of P. bimaculatum is smooth. The molecular phylogenetic position of this new taxon was inferred from SSU and LSU rDNA genes. In both phylogenetic analyses, P. bimaculatum branched with high support with Prorocentrum consutum and formed a clade sister to the one including P. lima and related species such as P. arenarium, P. belizeanum, P. hoffmannianum, and P. maculosum. From the phylogenetic study, since most species related to P. bimaculatum are known for their toxic effects and production of okadaic acid, this new species can be considered as a potential toxin producer, but this has to be analyzed.

Microalgal blooms occur in Kuwait's waters year round. Seasonal non-harmful blooms are part of the annual succession in marine ecosystems and are a typical phenomenon in Kuwait's waters as well as in the Gulf region. The ecology and taxonomy of phytoplankton in Kuwait's waters have been studied during the past few decades; however, only very limited detailed taxonomical studies have been done on marine phytoplankton as a whole, as well as on potentially harmful species. Together with the phytoplankton, benthic microalgae are important primary producers and an essential component of the intertidal zone in Kuwait's marine environment. Potentially toxic microalgae were found in the intertidal sediments of Kuwait. A total of 62 identified taxa can be categorized as potentially harmful species in the collected samples from Kuwait's waters and intertidal flats. Among them, 43 taxa are potentially toxic to humans and marine biota, and 10 taxa are potentially harmful to fish and invertebrates. Potentially toxic species are usually recorded in low densities in Kuwait's waters. However, the presence of a significant number of potentially harmful species in its phytoplankton can be regarded as a significant finding with latent hazards for humans and marine ecosystems. Documentation of this sporadic high abundance together with significant species richness of the potentially toxic phytoplankton, requires more intensive and comprehensive studies of Kuwait's marine environment.

Studies of the phytoplankton community were conducted in the north-western Arabian Gulf in 2005 and 2006. Seven stations throughout Kuwait’s waters were sampled. Th e infl uence of nutrient-rich freshwaters from the Shatt al-Arab resulted in high phytoplankton productivity characterized by high species diversity with a strong dominance of diatoms, especially in northern Kuwait. Phytoplankton species richness gradually increased from north to south. Spatial distribution of both total abundance and biomass of phytoplankton indicated signifi cant diff erences in species structure and size spectrum of the microalgae. Th e analysis of the temporal and spatial phytoplankton variability (distribution of total abundance and biomass, similarity of species compositions and local community structure) indicated that Kuwait’s northern waters diff ered from areas further south in terms of phytoplankton structure and temporal and spatial variability. Environmental heterogeneity is mainly attributed to the infl uence of the Shatt al-Arab system, which aff ects the temporal and spatial variability of the phytoplankton community.

A new benthic dinoflagellate species, Prorocentrum bimaculatum sp. nov., is studied from Kuwait's marine sediments, based on detailed morphological and molecular data. Cells are large, oblong oval in shape. They are 49.9-55.3 μm long and 38.4-43.2 μm wide. The ornamentation of this new species is peculiar, and characterized by smooth valves with large pores (0.32-0.50 μm) scattered on their surface, except in two circular patches of ∼15 μm in diameter, devoid of ornamentation and located on both sides of the valve centers. The periflagellar area is widely triangular, located in a moderate excavation of the right valve, and comprises nine platelets. The intercalary band of P. bimaculatum is smooth. The molecular phylogenetic position of this new taxon was inferred from SSU and LSU rDNA genes. In both phylogenetic analyses, P. bimaculatum branched with high support with Prorocentrum consutum and formed a clade sister to the one including P. lima and related species such as P. arenarium, P. belizeanum, P. hoffmannianum, and P. maculosum. From the phylogenetic study, since most species related to P. bimaculatum are known for their toxic effects and production of okadaic acid, this new species can be considered as a potential toxin producer, but this has to be analyzed.

We studied benthic harpacticoid grazing on diatom algae from two sites on the White Sea intertidal sandflat. Diatoms from sediments and from harpacticoid gut contents were sampled in situ, identified and counted, and grazing rates were calculated by two ways: (1) using potential daily ration estimations and (2) from the gut content and gut-residence time data. Paraleptastacus kliei did not contain any diatoms in the guts and presumably fed on other objects (bacteria or flagellates). Two other dominating species studied, Heterolaophonte minuta and Huntemannia jadensis, contained an average of 604 and 222 diatom cells per specimen. Diet composition differed significantly from the natural algal community. Two diatoms of intermediate cell size (Nitzschia palea var. debilis and Navicula sp.) contributed 92–97% of gut content for H. minuta and 58–81% for Hn. jadensis, whereas these diatoms amounted to only about 10% of biomass in native community. Mean consumption rates were estimated as 50–200 μg of wet biomass/day/cm2, so the harpacticoids grazed only between 3 and 11% of the total microalgae biomass per day. The grazing impact on the two preferred diatom populations, however, was much more intensive, 10–30% per day for Navicula sp. and 55–228% for N. palea. Therefore, native harpacticoid populations demonstrate highly selective feeding and could be strongly limited by their food in spite of seemingly plentiful total abundance of microphytobenthos. This disproportionally high grazing pressure upon some species apparently could affect the structure of microalgae communities resulting in low relative abundance of mid-sized forms. We hypothesize that a very dynamic spatio-temporal distribution of epibenthic harpacticoids (short-living micropatches) may be the possible adaptation to such local food limitation.

Meiobenthos (harpacticoids), microzoobenthos (ciliates) and microphytobenthos (epipelic diatoms and dinoflagellates) were collected during July 1999 using nested sampling at the scales of decimeters, meters and tens of meters. Similarity between samples decreased rapidly with distance for all groups, but unicellular organisms were distributed more heterogeneously at a large scale than meiobenthos. Microspatial (decimeter scale) variations contributed the main part of total variation of harpacticoid abundance, while the large-scale differences were less important. On the contrary, these differences yielded the main variability for ciliates and especially for microalgae. The relative role of temporal variability decreased steadily for the smaller-sized organisms. Stability of spatial structure at multiple scales was estimated by Mantel correlations, Rm, between the successive similarity matrices. For harpacticoids, the results showed intensive and chaotic turnover of microaggregations. For microbenthos, rather high Rm values were found in smaller scales: tens of meters—for ciliates, from meters on—for dinoflagellates, and already from decimeter scale and on—for diatoms. Thus, the general spatial pattern (that is the arrangement of micropatches) was more stable for microbenthos than for meiobenthos. Temporal variability of species structure, in contrast to the spatial one, was highest for the smallest organisms. Correlations between size groups, using both total abundance and species composition, differed for microspatial, meso-spatial or temporal distribution. At the microscale, there were slight but significant negative correlations between harpacticoids and microalgae. Meso-scale distribution of dinoflagellates and diatoms differed significantly due to their different preferences in sediment properties. Ciliates were strongly positively correlated with dinoflagellates. At the microscale, each group had an individual community pattern. At larger scales, species composition of diatoms, ciliates and harpacticoids varied in space in coordination, while dinoflagellates behaved independently. It is hypothesized that body size determines the spatio-temporal scale of the perception of environmental heterogeneity.

An investigation of vertical distribution, rhythms of vertical migration and division of epipelic free-living diatom algae was carried out at different sediment depths on intertidal sandflat in the Chernaya River Estuary (Kandalaksha Gulf, White Sea, Russia) during the summers of 1994-2001. The depth of penetration of viable microalgae cells in the sediment did not exceed 4.2 cm in the areas with clay sublayers, where zones with high negative Eh values were located closer to the surface. Diatom habitats in the areas with coarse sand sublayers extended to more than 8 cm depth. Approximately 40% of diatoms were present in the topmost 2 mm layer. The subsurface portion of diatom cells on average was concentrated within the layer with Eh values ranging from 0 to -80 mV. Eh values below -100 mV limited diatom penetration in deep anoxic sediment layers. The deep portion of diatom populations consisted basically of dividing cells. A cytological analysis of diatom cell distribution showed that the proportion of cells in the different phases of mitosis increased with increasing depth, and reached 80 to 90% at a depth of 2 to 3 cm. The regular presence of dividing diatom cells almost exclusively in aphotic anoxic sediments was noted first. The study of the dynamics of microphytobenthic vertical distribution revealed active diurnal vertical migration depending on temperature, light and tide regimes. The frequency of doublet cells (FDC) in epipelic diatom populations was in inverse proportion to cell concentrations in the photic zone. Diatom divi- sion was registered only during incubation in the porewater, which was rich in inorganic nutrients and dissolved organic matter. We suppose that a more stable habitat with higher concentrations of nutrients (especially nitrogen) in their more reduced forms (NH4 + instead of NO3 - ) provides more favourable conditions for cell growth and division at the depth of several cm within the sediment compared, to the surface layer. Migration activity of diatom algae is an adaptation which permits cells to consume energy and to undergo fission under optimum conditions in spatially disconnected zones.

Even though very few biological data on dinoflagellates from Iraqi aquatic ecosystems are available to date, there are none on the genusScrippsiella. For this reason, the survey was conducted along four sites in the Shatt Al-Arab River between November 2009 and July 2010. A dense population ofScrippsiella-like dinoflagellate was observed in the studied samples during November and December 2009. Less dense population of the same taxon was encountered in the downstream sites in July 2010. Based on observations of thecal plate pattern in epifluorescence microscopy, the species was attributed toScrippsiella trochoidea. The occurrence ofS. trochoideais reported for the first time in Iraqi waters from a wide range of temperature (17.9°C–35.2°C) and salinity (2.3–16.7).

The occurrence of noctilucoid dinoflagellates Abedinium dasypus and Scaphodinium mirabile is reported for the first time from the Indian Ocean (Kuwait's waters, north-western Arabian Gulf). The morphology of live cells is described on the basis of light microscopic examination and photographically documented for both species. The world distribution of these dinoflagellates is reviewed.

The occurrence of the dinoflagellate Kryptoperidinium foliaceum is reported for the first time from a hypersaline environment in Kuwait based on recurrent observations of this species from a tidal creek in appreciable numbers. This new record extends the known range of salinity tolerance for K. foliaceum to more than 100 psu. The distribution of the species along a salinity gradient within the tidal creek was studied. The morphological features of the species on the basis of light and epifluorescence microscopy observations are described.

The Gulf is located in a subtropical, hyper-arid region. It is shallow, and bordered by several wealthy states (Fig. 16.1) undergoing rapid economic growth involving substantial construction along shores and offshore regions, underpinned by its oil and gas industry, and by wealth derived from financial centres. Thriving economic activity has, over the past few decades, begun to exert significant pressure on the Gulf’s marine environment. It is changing rapidly, by developments which include construction, substantial coastline alterations, habitat loss, creation of beds of shifting or suspended sediments, and temperature and salinity changes in restricted water flows along the coast, as well as by climate warming. The Gulf suffers from a “shifting baseline syndrome” (Pauly 1995; Sheppard 1995) and it is difficult to find any meaningful baselines, not only because of ongoing, intensive constructions that cause large-scale alterations of the environment, but also because of several recent episodes of marine mortality from seawater warming.

This review examines the substantial changes that have taken place in marine habitats and resources of the Gulf over the past decade. The habitats are especially interesting because of the naturally high levels of temperature and salinity stress they experience, which is important in a changing world climate. However, the extent of all natural habitats is changing and their condition deteriorating because of the rapid development of the region and, in some cases from severe, episodic warming episodes. Major impacts come from numerous industrial, infrastructure-based, and residential and tourism development activities, which together combine, synergistically in some cases, to cause the observed deterioration in most benthic habitats. Substantial sea bottom dredging for material and its deposition in shallow water to extend land or to form a basis for huge developments, directly removes large areas of shallow, productive habitat, though in some cases the most important effect is the accompanying sedimentation or changes to water flows and conditions. The large scale of the activities compared to the relatively shallow and small size of the water body is a particularly important issue. Important from the perspective of controlling damaging effects is the limited cross-border collaboration and even intra-country collaboration among government agencies and large projects. Along with the accumulative nature of impacts that occur, even where each project receives environmental assessment or attention, each is treated more or less alone, rarely in combination. However, their combination in such a small, biologically interacting sea exacerbates the overall deterioration. Very few similar areas exist which face such a high concentration of disturbance, and the prognosis for the Gulf continuing to provide abundant natural resources is poor. © 2009.

Taxonomic data of free-living benthic flagellates in Kuwait’s intertidal sediments are summarized. A full list of the species composition is presented, including distribution on different sediment types, species occurrence and light micrographs for each taxon identified. A total of 67 flagellate species were identified, representing six classes. Most of them are reported from Kuwait for the first time. The most abundant and diverse species were sand-dwelling dinoflagellates (43 taxa).