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We report the first occurrence of a diatom species, Nitzschia navis-varingica in the Sea of Marmara. Previously, this species was observed in the Mediterranean Sea in 2016. Samples were collected from the coast of Darıca, Istanbul, Turkey, on 22 June 2021 during a large-scale mucilage event. The species was isolated, cultured under laboratory conditions, and investigated with scanning electron microscopy and light microscopy.

We report the complete chloroplast genome of the MED1 strain of Nephroselmis pyriformis from the Eastern Mediterranean Sea. At 111,026 bp, this genome is smaller and more compact than those of Neph...

Microalgal species have been used as a food source and as medicine since ancient times in Africa, Mexico and China. In our study we focused on the whole cell extracts of three microalgal species that have not been studied before: the diatom Nitzschia navis-varingica, the haptophyte Chrysochromulina aliferaand the dinoflagellate Heterocapsa pygmaea.Effects of the diatom Nitzschia navis-varingica, the haptophyte Chrysochromulina aliferaand the dinoflagellate Heterocapsa pygmaeaon mammalian macrophage cells were investigated first time in this study.A significant anti-inflammatory impact of cell extracts in distilled water was observed.Direct anti-inflammatory influence of the extracts without any solvents or further processes facilitates its usage in biotechnology. Furthermore, the ability to include these species in the human diet brings out new opportunities in terms of increasing the tolerance to certain allergic food products in patients with allergic reactions as well as inflammatory bowel disease. Moreover, these species can be used in the creams for the atopic applications on the skin to prevent skin allergies. With this study, we are presenting data supporting the biotechnological potential of the diatom Nitzschia navis-varingica, the haptophyte Chrysochromulina aliferaand the dinoflagellate Heterocapsa pygmaea species against inflammatory and allergic reactions.

Simple Summary Diatoms are microalgae known for their ecological importance. Among them, just a few species are able to produce a blue pigment. We describe Haslea silbo sp. nov., a cosmopolitan species of blue diatoms, found on both sides of the Atlantic Ocean. The description includes the use of both microscopy and next generation sequencing. It has been possible to observe its reproduction in the laboratory, and the blue pigment it produces has also been studied. Abstract Specimens of a new species of blue diatoms from the genus Haslea Simonsen were discovered in geographically distant sampling sites, first in the Canary Archipelago, then North Carolina, Gulf of Naples, the Croatian South Adriatic Sea, and Turkish coast of the Eastern Mediterranean Sea. An exhaustive characterization of these specimens, using a combined morphological and genomic approach led to the conclusion that they belong to a single new to science cosmopolitan species, Haslea silbo sp. nov. A preliminary characterization of its blue pigment shows similarities to marennine produced by Haslea ostrearia, as evidenced by UV–visible spectrophotometry and Raman spectrometry. Life cycle stages including auxosporulation were also observed, providing data on the cardinal points of this species. For the two most geographically distant populations (North Carolina and East Mediterranean), complete mitochondrial and plastid genomes were sequenced. The mitogenomes of both strains share a rare atp6 pseudogene, but the number, nature, and positions of the group II introns inside its cox1 gene differ between the two populations. There are also two pairs of genes fused in single ORFs. The plastid genomes are characterized by large regions of recombination with plasmid DNA, which are in both cases located between the ycf35 and psbA genes, but whose content differs between the strains. The two sequenced strains hosts three plasmids coding for putative serine recombinase protein whose sequences are compared, and four out of six of these plasmids were highly conserved.

A benthic diatom, Nitzschia navis-varingica was found for the first time in the Mediterranean Sea. Effects of this diatom species together with the haptophyte Chrysochromulina alifera and the dinoflagellate Heterocapsa pygmaea isolated from the northeastern Mediterranean Sea coast on prostate, breast cancer and fibroblast cell lines were investigated. Algal extracts did not exert any toxic effect on these cell lines and it had growth stimulatory impact on the cells without discrimination of cell type. Our results suggest potential use of these algal extracts in tissue repair and cell growth boosting additive in the diet of humans as well as animals. Moreover, these algal extracts have potential to be used as natural resource in the skin vitalizing creams of cosmetics industry and as wound healing agents in the atopic drugs.

Abundance and carbon biomass of different phytoplankton groups obtained by microscopy were compared with taxonomy derived from pigment measurements and CHEMTAX analysis of samples collected in June 2006 in the NW Black Sea. The diatom Chaetoceros curvisetus was dominant in terms of carbon biomass based on cell volume at inshore stations, while the coccolithophore Emiliania huxleyi was prevalent at offshore. Emiliania huxleyi reached bloom abundance of 3.3 × 106 cells L− 1. The chlorophyll a (chl a) concentration within phytoplankton groups as allocated by CHEMTAX was in agreement with microscopy derived carbon biomasses of the taxonomic groups diatoms, dinoflagellates and cryptophytes only. Carbon biomass of less abundant phytoplankton taxa (cyanophytes, euglenophytes and chlorophytes) did not correlate with group-specific chl a. It was not possible to detect E. huxleyi bloom by CHEMTAX analysis probably due to much higher biomass of other species containing 19’-hexanoyloxyfucoxanthin. Nutrient concentrations were generally high in the waters where diatom and dinoflagellates dominated the community but low in the area of E. huxleyi bloom. A good correlation between total carbon biomass of phytoplankton and chl a was found and the estimated C:chl a ratio of phytoplankton varied between 36 and 256 (in average 124 ± 50).

Monitoring for 6 years (2001–2006) showed that the population explosion of the alien ctenophore Mnemiopsis leidyi in the southern Caspian Sea coincided with a decline in the abundance and species number of mesozooplankton. While this decline appeared to have reduced the nourishment of sprat (also known as kilka), it seemed to have affected phytoplankton favorably mainly due to the decrease in grazing pressure. During 2001–2002, when M. leidyi abundance and biomass were at their highest levels, abundance of dinoflagellates and cyanophytes exceeded that of diatoms. Before the invasion (1996) and in some years after the invasion (2003, 2004 and 2006) diatom abundance was higher than the abundance of other groups. In September 2005, an unprecedented bloom of the toxic cyanophyte Nodularia sp. was observed in the southern Caspian Sea. Disappearance of edible zooplankton such as Eurytemora spp. was among the first changes observed after the expansion of M. leidyi in the area. Some changes in the macrobenthic fauna were also conspicuous after the increase of this ctenophore. While the biomass of some deposit feeders, such as the polychaete Nereis diversicolor and oligochaete species increased, benthic crustaceans decreased sharply in abundance during 2001–2003 and completely disappeared during 2004–2006. Iranian catches of kilka, the most abundant and widespread zooplanktivorous fish, decreased significantly in the southern Caspian Sea after 1999. Iranian landings of kilka dropped ~70% from 69,070 ± 20,270 t during 1995–2000 to 23,430 ± 12,240 t during 2001–2006, resulting in a loss of at least 125 million US dollars to the economy. There were also changes in the total catches of large predators such as the kutum and mullet, which mainly feed on kilka, between 1991 and 2006.

Effects of atmospheric deposition and other environmental factors on phytoplankton dynamics were evaluated from an open (having offshore characteristics) and a coastal station in the northeastern Mediterranean between December 2000 and December 2001. Data on phytoplankton, chlorophyll a, nutrients, temperature and salinity were obtained at bi-weekly or more intense intervals during 1 yr, whilst transport of Saharan dust towards the sampling region was monitored daily by SeaWiFS (sea-viewing wide field-of-view sensor) images. Diatoms were the group of highest average biomass during the entire investigation period. Although coccolithophores (mainly Emiliania huxleyi) numerically dominated at the open station during the study period, their maximum abundance was as low as 50 x 10 3 cells l -1 . The intensity of dust transport was observed to be highest in spring. Less intense transports were observed in summer and autumn. Several intense episodic dry and wet dust deposition events during the spring season observed by SeaWiFS images caused little or no increase in phytoplankton abundance and biomass in the following days and weeks. Nevertheless, it appears that less intense dust transport events increased phytoplankton abundance and biomass in August, September and October 2001, when water column stratification was at its peak. However, these increases were much weaker than the major winter-early spring bloom (in February and March), which was caused by upwelling, mixing the water column. We suggest that the impact of atmospheric nutrient input on phytoplankton in the Mediterranean is rather low on a yearly basis.

The effects of nitrate, ammonium and phosphate on the abundance, chlorophyll a content (chl a), in vivo fluorescence, particulate organic carbon, nitrogen, phosphorus and cell morphology of the diatom Skeletonema costatum, the dinoflagellate Prorocentrum micans and the coccolithophore Emiliania huxleyi were investigated in the laboratory. The carbon:chlorophyll a ratio (as weight), a parameter often used in productivity estimates, differed substantially among the three species as well as at different nutrient concentrations at the end of the exponential growth phase. The cell chl a content was higher in the earlier phases of growth in all three species in agreement with previous investigations. Average chl a content per cell during the experiments was higher in P. micans (8 pg) than in S. costatum (0.4 pg) and E. huxleyi (0.2 pg). However, chl a content per unit volume was higher in E. huxleyi (~15 fg μm−3) than in S. costatum (~7 fg μm−3) and P. micans (~1 fg μm−3). Prorocentrum micans cultures reached the highest total biovolume (74 mm3 L−1 and was 3 and 5 times higher than S. costatum and E. huxleyi cultures, respectively) under high nutrient concentrations. Nevertheless, total chl a concentration of S. costatum culture was almost twice higher (122 μg L−1) than that of the other two species at the end of the exponential growth phase. Phosphate consumption by S. costatum occurred at higher rates compared to the other two species during the experimental period, probably showing that this nutrient was more favourable for this species. Our findings from these laboratory experiments emphasize that chl a values in the natural habitat may not accurately indicate actual phytoplankton biomass.

The species composition, abundance, and biomass of micro- (>15 μm) and nano- (

Bu derlemenin amacı bitkisel planktonun ekolojik önemini ve iklim değişikliğindeki rolünü incelemektir. Denizlerde besin zincirinin en alt halkasını oluşturan fitoplanktonun karbon üretimi dünya birincil üretiminin yarısını karşılamaktadır. Fitoplankton yeryüzündeki oksijenin de yarısını üretmektedir. Bu tek hücreli organizmalar küresel iklim değişikliğinde de rol oynamaktadır. İki farklı mekanizma ile fitoplanktonun küresel ısınmayı azaltabileceği önerilmiştir. Birincisinde bu fitoplankton atmosferden karbondioksiti alıp organik karbona çevirir ve ölen organizmalarla deniz tabanına gönderilir. Dolayısıyla atmosferdeki karbondioksit miktarı azalarak sera etkisi azaltılmış olur. İkinci mekanizma okyanuslarda yaygın olarak görülen bazı fitoplankton gruplarından çıkan dimetilsülfat gazı ile gerçekleşir. Bu gaz atmosferde sülfat aerosollerine yükseltgenerek bulut yoğunlaşma çekirdeği olarak görev yapar. Bulut oluşumu güneş ışınlarının yeryüzüne ulaşmasını engelleyeceği için bu gazın küresel bir soğumaya yol açabileceği belirtilmiştir. Biyosferdeki bitki kütlesinin sadece %0,2’sine karşılık gelen fakat tüm deniz canlılarının direk veya dolaylı olarak besin kaynağı olan fitoplanktonun çağın en büyük sorunlarından biri olan küresel ısınmayı etkileyebildiği düşünüldüğünde bu organizmaların ekosistemdeki yeri ve önemi daha iyi anlaşılmaktadır.

Lessardia elongata Saldarriaga & Taylor is identified for the first time in the north-western Black Sea in the present study. This species has probably been recorded with different names in the Black Sea due to lack of detailed investigations with scanning electron microscopy (SEM) or fluorescence microscopy. Our identification is based on observations with an electron microscope in September 2004 and with an epifluorescence and light microscope in June 2006. Cells were 5–10 µm wide, 22–30 µm long in formaldehyde fixed samples, fusiform, transparent, and had a faint broad girdle. Epitheca was slightly larger than the hypotheca and recently ingested prey could often be seen in the antapical half of the cell within very conspicuous vacuoles. Thin and faint thecal plates were hardly visible under epifluorescence microscope after staining the cells with fluorescence brightener 28 in the fixed samples. Cell abundances up to 18,400 cells l–1 and 87,000 cells l–1 were observed in September 2004 and June 2006, respectively.

The invasive ctenophore Mnemiopsis leidyi (Agassiz) which was transported from the Black Sea into the Caspian Sea at the end of the 1990s, has negatively affected the ecosystem of the Caspian Sea. Zooplankton abundance, biomass and species composition were evaluated on the Iranian coast of the Caspian Sea during 2001-2006. A total of 18 merozooplankton (13 species composed of larvae of benthic animals) and holozooplankton (4 Copepoda and 1 Cladocera) species were identified. The total number of zooplankton species found here was 50% less than in a previous investigation performed in the same region in 1996 before the introduction of M. leidyi into the Caspian Sea. Cladocera species seemed to be highly affected by the invasion of M. leidyi; only one species, Podon polyphemoides, remained in the study area, whereas, 24 Cladocera species were found in the study carried out in 1996. While Copepoda Eurytemora minor, E. grimmi, Calanipeda aquae dulcis and Acartia tonsa were abundant before the M. leidyi invasion, only A. tonsa (copepodites and adults) dominated the inshore and offshore waters after the invasion. The maxima in zooplankton abundance (22,088 ± 24,840 ind.m-3) and biomass (64.1 ± 56.8 mg.m-3) were recorded in December 2001 and August 2004, respectively. The annual mean zooplankton abundance during 2001-2006 was in the range of 3,361- 8,940 ind.m-3 which was 2-5 fold less than the zooplankton abundance in 1996. During 2001-2006, the highest abundance and biomass of M. leidyi were observed during summer-autumn coincident with warm temperatures and generally when abundance of other zooplankton organisms was low., JRC.H.5-Land Resources Management

A significant correlation was observed between satellite derived chlorophylla(Chla) concentrations and the biomass of the invasive comb jellyfishMnemiopsis leidyiin the southern Caspian Sea. By consuming the herbivorous zooplankton, the predatory ctenophoreM. leidyimay have caused levels of Chlato rise to very high values ( mg ) in the southern Caspian Sea. There might also be several other factors concurrent with predation effects ofM. leidyiinfluencing Chlalevels in this region, such as eutrophication and climatic changes which play major roles in nutrient, phytoplankton, and zooplankton variations. The decrease in pelagic fishes due to overfishing, natural, and anthropogenic impacts might have provided a suitable environment forM. leidyito spread throughout this enclosed basin.

The contribution of phytoplankton groups to total chlorophyll a (chl a) was derived using CHEMTAX from pigment measurements by HPLC and compared with the carbon (C) biomass estimations obtained from microscopy in the southern Baltic Sea in April 2005. Five different matrices of pigment:chl a input ratios, derived from the literature, were tested. Successive runs of CHEMTAX showed peridinin:chl a for dinoflagellates and fucoxanthin:chl a for diatoms to converge at 0.452 ±0.02 (mean ± SD) and 0.489 ± 0.03, respectively, with initial ratios varying by a factor of 2 to 3 across matrices. The 2 techniques were in relatively good agreement for the dominant phytoplankton groups. Peridinin, diadinoxanthin, chlorophylls c1 and c2 (here grouped together as chl c1+c2), fucoxanthin and alloxanthin were the principal accessory pigments; dinoflagellates, diatoms and cryptophytes were the groups forming the majority of the C biomass. Diadinoxanthin and chl c1+c2 were mainly associated with the dominant dinoflagellates rather than with other phytoplankton classes. Excluding cyanophytes, the correlation between carbon biomass of other minor phytoplankton groups and their chl a was either poor or not significant due to uncertainties in either microscopic counts or CHEMTAX classification. There was a good correlation between carbon biomass of phytoplankton and chl a. The estimated C:chl a ratio of total phytoplankton varied between 8 and 40 (in average 20 ± 7), with a higher value for dinoflagellates (30 ± 17) than for diatoms (9 ± 7). Fucoxanthin- containing small flagellates might have led to the overestimation of the diatom contribution by CHEMTAX at a few stations., JRC.H.3-Global environement monitoring

The chemical composition of suspended particulate organic matter (SPOM) in the Black Sea water column has been characterized by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The results are discussed in terms of the hydro-chemical properties of the water column. Phytoplankton cultures grown in the lab also were analyzed to provide reference information for the euphotic zone SPOM. The composition of SPOM in the Black Sea displays important vertical variations dependent on specific distinct biochemical processes in the water column. Identical pyrolysis markers indicative for proteins, lipids, carbohydrates and chlorophylls were obtained from SPOM in the euphotic zone of the Black Sea and the phytoplankton cultures. Nevertheless, the relative contribution of lipids and carbohydrates to Black Sea SPOM was higher than in phytoplankton cultures. The lipid to protein ratio throughout the water column seems to determine the C/N ratio of SPOM. Below the oxycline, the relative contribution of proteins to the SPOM pool increased while the lipid content of the SPOM decreased. The protein composition changed substantially in the suboxic/anoxic transition zone, as expressed by the increase in pyrrole/indole ratio. Elemental sulfur was observed in particulates suspended at the upper anoxic zone, and the relative intensity of the S8 peak varied regionally with more intense multi-peaks in SW shelf-break station, in agreement with the lateral flux of O2. Sulfur-containing organic compounds (e.g. thiophenes), including organic polysulphides (e.g. 1,2-dithiole-3-thiones) were detected in some deep anoxic samples, indicating that sulphurization of organic matter may be active in the water column.