Environmental assessment of oyster beds in the northern Arabian Gulf Coast of the United Arab Emirates.

The United Arab of Emirates (UAE) hosts valuable coastal and marine biodiversity, and oysters are one of the habitants of its marine ecosystem. Oysters play an essential role in the nearshore coasts where they work as an active filter. They filter nutrients, phytoplankton, sediments, heavy metals, and toxins out of the water, which improves the water quality. This is the first study that characterizes oyster bed habitats in the UAE by analyzing water quality parameters, polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs)and heavy metals in water, sediments and oyster samples collected from five locations along the coasts of Sharjah, Ajman, and Umm al Quwain. Oyster bed areas supported a diverse assemblage of benthic life including oysters, scallops, pen shells, hard corals, and macroalgae. Mobile species in these habitats included groupers, emperors, snappers, sea snakes, among others. The phytoplankton assemblages were dominated by diatoms, dinoflagellates, and small cryptophytes. Harmful diatom Pseudonitzschia was found in all locations. No detectable concentrations of PAHs and OCPs were reported in this study, and water quality parameters were within the acceptable levels for the region. On the other hand, water quality index was reported marginal, mostly due to the presence of higher than acceptable concentrations of chromium and mercury in all sites studied. Bioconcentration factors concluded that oysters were able to bioconcentrate metals such as arsenic, cadmium, chromium, and zinc, when compared to water. No detectable concentrations of lead and mercury were reported in oysters, suggesting higher depuration rates for those metals.

Phytoplankton bloom detection during the COVID-19 lockdown with remote sensing data: Using Copernicus Sentinel-3 for north-western Arabian/Persian Gulf case study.

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.

Laciniporus arabicus gen. et sp. nov. (Dinophyceae, Peridiniales), a new thecate, marine, sand-dwelling dinoflagellate from the northern Indian Ocean (Arabian Sea)1.

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.

Ailadinium reticulatum gen. et sp. nov. (Dinophyceae), a New Thecate, Marine, Sand-Dwelling Dinoflagellate from the Northern Red Sea.

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.

Composition, diversity and distribution of microbenthos across the intertidal zones of Ryazhkov Island (the White Sea).

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.

PROROCENTRUM BIMACULATUM SP. NOV. (DINOPHYCEAE, PROROCENTRALES), A NEW BENTHIC DINOFLAGELLATE SPECIES FROM KUWAIT (ARABIAN GULF)(1).

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.

The Gulf: a young sea in decline.

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.