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Light micrographs of selected diatom taxa found in Lake Mrtvo More in 2016. A-G -Cocconeis scutellum var. scutellum, H-O -Cocconeis costata, P-S -Cocconeis dirupta var. flexella, T-V -Licmophora flabellata, W, X -Licmophora paradoxa, Y, Z -Rhabdonema adriaticum, AA -Halamphora hyalina, AB, AC -Halamphora kolbei, AD -Navicula flagellifera, AE -Nitzschia frustulum, AF, AG -Opephora mutabilis, AH, AI, AJ, AK -Mastogloia cuneata. Scale bar: 10 µm applies to all images.
Source publication
The initial colonization of bacteria and diatoms on a immersed artificial substrate and the development of diatom assemblages in relation to physico-chemical parameters were investigated on a weekly basis at one station in the marine Lake Mrtvo More, South Croatia, from April to October 2016. According to TRIX trophic index, lake showed different t...
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Context 1
... scutellum, while motile forms were better related in the samples from July, August and September (Fig. 5). Taxa presented in the samples collected from July to September were associated with higher seawater temperature and higher nutrient concentrations (e.g. P. rudum, R. adriaticum, T. coarctata). Erect diatoms (e. g. L. paradoxa, L. flabellata, Fig. 6) appeared in October, when salinity was low. Tab. 1. Diatom taxa with their average abundances contributing to dissimilarities (cumulative = 90%) between diatom assemblages from Group 1 and Group 2, according to SIMPER analysis. Av.abund. -average abundance, Av.diss. -average dissimilarity, Contrib. -contribution to differences (%), ...
Context 2
... scutellum, while motile forms were better related in the samples from July, August and September (Fig. 5). Taxa presented in the samples collected from July to September were associated with higher seawater temperature and higher nutrient concentrations (e.g. P. rudum, R. adriaticum, T. coarctata). Erect diatoms (e. g. L. paradoxa, L. flabellata, Fig. 6) appeared in October, when salinity was low. Tab. 1. Diatom taxa with their average abundances contributing to dissimilarities (cumulative = 90%) between diatom assemblages from Group 1 and Group 2, according to SIMPER analysis. Av.abund. -average abundance, Av.diss. -average dissimilarity, Contrib. -contribution to differences (%), ...
Citations
... Despite their ecological importance, the taxonomic knowledge of benthic diatoms in marine coastal environments is still rather low compared to freshwater ecosystems. However, in the last decades, there have been intense efforts to understand the diatom flora growing on different substrata in the coastal regions (Semina 2003;Álvarez-Blanco and Blanco 2014;Park et al. 2018;Car et al. 2020;Nunes et al. 2022). When identifying benthic communities, small cells (nanoplankton; approximately 20 µm or less) and/or cryptic species could create a challenge to diatom taxonomy. ...
... The artificial coastline seems to limit the diatom dispersal in Istanbul. Formerly, composition differences were observed between artificial and natural substrates (Albay and Akcaalan 2003;Potapova and Charles 2005) or alterations in diatom assemblages reflecting environmental changes were reported (Car et al. 2020). Although substrate specificity was observed in small-scale research areas where environmental factors became relatively less important (Bere and Tundisi 2011), it was also indicated that no significant differences were found on diatom assemblages at different substrates (Jüttner et al. 1996). ...
... In addition, the taxonomic knowledge of marine benthic ecosystems is still insufficient compared to freshwater benthic diatoms (Pérez-Burillo et al. 2022) and there is a lack of expertise in marine benthic diatom taxonomy. In contrast to freshwater diatoms, dissimilarities in diatom composition are higher in different coastal areas, possibly with salinity as a major driving factor (Car et al. 2020;Risjani et al. 2021). Therefore, there may be difficulties in characterizing the flora of specific coastal sites. ...
The importance of sustainable bioassessment and management of coasts to maintain good trophic status is increasing due to the high anthropogenic impacts on marine ecosystems. Diatoms are one of the most important assemblages and useful tools for assessing the state of the environment due to their advantages over other organisms such as short life span and rapid reaction to environmental changes in aquatic systems. In this study, our objective was to investigate marine benthic diatoms and compare them using three different methods: light microscopy (LM), scanning electron microscopy (SEM), and molecular metabarcoding (MB). LM observations were supported by SEM; in addition, 18S rRNA metabarcoding was used to reveal the diatom flora. The results showed that the highest number of genera was observed with LM (49), followed by SEM (27) and MB (21). Eight genera were found to be common by all three methods. Although MB identified a small number of genera, it verified the presence of common taxa through a rigorous analysis. However, all the methods used gave consistent results in confirming that the diatom assemblages found along the coasts of Istanbul in the Sea of Marmara exhibited low diversity. Our results suggest that the morphological approach to the study of marine benthic diatoms can be complemented by the metabarcoding approach, which showed encouraging results, and that both approaches can be mutually supportive.
... Partecta are narrow, and uniform and terminate before reaching the apices. The taxon is possibly common in warm coastal waters (Hustedt & Jensen, 1985;Witkowski et al., 2000), although not commonly reported, and is also present in the Adriatic Sea and Greek coasts (Loir, 2010(Loir, -2014Car et al., 2020). Hustedt, 1933 Fig. 4E, F References: Hustedt & Jensen (1985), Loir & Novarino (2013). ...
This study reports on newly recorded and several rare marine benthic diatoms from the Turkish coasts of the Aegean Sea. Altogether 510 species were observed from 6 locations throughout the Aegean Sea, and taxonomic and biogeographic remarks concerning thirty-four new recorded species are presented. Amongst the represented taxa, Amicula, Auricula, Cyclophora, Minidiscus, Oestrupia and Ralfsiella were observed for the first time in Turkish coastal waters. Biddulphia seychellensis, Cyclophora tabellariformis, Grammatophora maxima, G. gibberula, Amphicocconeis mascarenica, Cocconeis maxima, Amicula specululum, Caloneis egena, Diploneis dalmatica, D. droopii, Mastogloia affinis, M. linearis, M. mauritana and Oestrupia powelii var. vidovichii, which were rarely recorded from the coasts of the oceans and the Mediterranean Sea, were examined by light microscopy (LM) and scanning electron microscopy (SEM). Also, the findings revealed that the geographic range of A. mascarenica, B. seychellensis, C. tabellariformis and Psammodictyon corpulentum, which were distributed in warmer marine waters, has expanded to the temperate waters of the Aegean Sea. Additionally, the recently described species Hyalosira septata, from the loggerhead sea turtle carapace and the Turkish Mediterranean Sea coast was observed in the Aegean Sea. This study contributes to the diatom knowledge of marine waters from the understudied Aegean Sea coasts of Türkiye, enhancing the biogeography of some rare and well-established taxa.
... The zooplankton/other groups in the studied shrimp farms were mostly composed of Ciliophora, Discosea, Gastrotricha, and Nematoda, which are phyla containing algal and bacterial predators (Nosek and Bereczky, 1983;Poinar, 2010;Riera and Todaro, 2012;Santoferrara et al., 2017;Fisher et al., 2019;Lotonin and Smirnov, 2020). The algal group mostly consisted of Bacillariophyta (diatom) and Chlorophyta (green algae) containing suspended microalgae (Car et al., 2020;Mohseni et al., 2020;Tahir et al., 2020). The bacterial group was mainly composed of Bacteroidetes, Chloroflexi, Cyanobacteria, and Proteobacteria (Kawaichi et al., 2013;Chen et al., 2019;Liu et al., 2019;Zammit, 2019;Tanay et al., 2020). ...
... panduriforme) and green algae (T. marina and Nannochloris sp.) types, which are photosynthetic floating microalgae (Car et al., 2020;Mohseni et al., 2020;Tahir et al., 2020). They absorb nitrogen sources, such as ammonia, and synthesize proteins through metabolism, including photosynthesis (El-Sheekh et al., 1994;González-Camejo et al., 2020). ...
Microbes are essential in biofloc technology for controlling nitrogen levels in water. The composition and function of microorganisms with biofloc systems were reported; however, data on microorganisms other than bacteria, such as algae (which are essential in the nitrogen cycle) and zooplankton (which are bacterial and algal predators), remain limited. The microbial communities (including bacteria, algae, zooplankton, and fungi) were investigated in shrimp farms using biofloc technology. Using Illumina MiSeq sequencing, the V4 region of 18S rRNA and the V3–V4 region of 16S rRNA were utilized for the analysis of the eukaryotic and prokaryotic microbial communities. As a result, it was found that the biofloc in the shrimp farm consisted of 48.73%–73.04% eukaryotic organisms and 26.96%–51.27% prokaryotic organisms. In these shrimp farms, prokaryotic microbial communities had higher specie richness and diversity than eukaryotic microbial communities. However, the eukaryotic microbial communities were more abundant than their prokaryotic counterparts, while algae and zooplankton dominated them. It was discovered that the structures of the microbial communities in the shrimp farms seemed to depend on the effects of predation by zooplankton and other related organisms. The results provided the nitrogen cycle in biofloc systems by the algal and bacterial groups in microbial communities.
... Even though our results are based on only spring and autumn observations, they can be easily interpreted as the effect of environmental variables on diatom distribution. Water temperature is known as a driving factor in marine waters (Car et al., 2020;Cotiyane-Pondo et al., 2021) and seems to have a similar effect on the distribution of benthic diatoms in the Sea of Marmara. Furthermore, salinity was another driving factor significantly affecting species richness. ...
... In terms of salinity, our results confirm that salinity can influence diatom distribution, however, it should be taken into consideration with other variables such as water temperature, light radiance or nutrients (Underwood et al., 1998;Wachnicka et al., 2010). It was also interesting that the common genera of marine waters which are known as pollution tolerant species (Car et al., 2020) did not seem to be influenced by the environmental variables here, even if members of these genera were relatively abundant in the highly mesotrophic and eutrophic coasts of the eastern Sea of Marmara. ...
The Sea of Marmara, located in northwest Turkey, comprises challenging environmental conditions and is an important bridge between the Black Sea and the Aegean Sea. In this study, we assessed the trophic situation of the coasts of the Sea of Marmara using the benthic diatom composition and their relation to the environmental variables in the spring and autumn of 2019 and 2020. A total of 120 samples were collected and 452 species were observed; Navicula Bory and Nitzschia Hassal were represented with the highest numbers of taxa. Analysis of Similarity (ANOSIM) revealed that diatom communities differed significantly between the spring-autumn periods and years. Canonical Correspondence Analysis (CCA) showed that diatoms grouped underwater temperature, salinity, dissolved oxygen, and TIN influence. TRIX observations revealed a highly mesotrophic-eutrophic status along the coasts. Our study contributes to the knowledge of diatom diversity, distribution and community changes in spring and autumn on the coasts Sea of Marmara. Our findings suggest that marine benthic diatoms could be used as eutrophication indicators in the coastal waters for long-term monitoring with the support of environmental parameters.
... Surprisingly, despite the grazing pressure by O. sinensis, a considerable biomass and diversity of diatom species was still present on the grazed panels. Car et al. (2020) also observed similar consumption of the periphyton by snails on artificial substrates. Overall, the grazing pressure at Site 2 was most likely the cause of the lower number of species observed at Site 2 compared to Site 1. ...
... The considerable weekly fluctuations in diatom abundances were characterised by diverse genera. Newly submerged substrates are known to be quickly colonised by bacteria, followed by pioneer diatom species (Pennesi and Danovaro, 2017;Car et al., 2020), depending on the species growth form and their ability to withstand factors such as competition and grazing once attached (Round et al., 1990; Fricke et al., 2016). The colonisation of substrate and the subsequent biofilm development was driven by the presence of the microphytobenthos at the site of interest. ...
... The colonisation of substrate and the subsequent biofilm development was driven by the presence of the microphytobenthos at the site of interest. The initial colonisation by bacteria enhances the attachment of diatoms on the substrate (Totti et al., 2007;Car et al., 2020). Benthic diatom species attachment is also facilitated by the nature of the substrate (Desrosiers et al., 2014) and the presence of suspended benthic species in the water column. ...
Benthic diatoms form an important component of the microphytobenthos and have long been utilised as suitable bioindicators in aquatic systems. However, knowledge on benthic diatom community succession on hard substrata (biofilm) remains understudied in austral marine coastal systems. In this study, we investigated benthic diatom colonisation on artificial substrates (Plexiglass) over a period of 5 weeks at two locations with different physical environments along the warm temperate coast of South Africa. Results revealed relatively similar physico-chemical conditions but highly contrasting diatom community development were observed between the two sites. While there were some shared taxa, site-specific dynamics resulted in significantly different diatom species diversity and richness, facilitated by common (e.g., Nitzschia ventricosa and Cocconeis scutellum) and a large percentage of rarely observed species such as Cocconeis testudo and Lyrella lyra. A total of 134 species belonging to 44 genera were observed during the study. The overall diatom composition differed spatio-temporally during the experimental period, with the fluctuating species occurrences and abundances highlighting the rapid microalgal species turnover within days, under natural conditions. Environmental variables were shown to have varying influences as drivers of the diatom community descriptors. Multivariate modelling confirmed that study site and the interaction between site and sampling occasion were important predictors of diatom abundances, and the overall observed community composition. The current results suggest that benthic diatoms on artificial substrata could be incorporated as suitable indicators of change along the coastline subject to further investigations, taking into account site-specific differences driven by habitat complexity and environmental variability. The experimental method proved to be efficient and can be implemented to study the response of benthic diatoms to localised nutrient enrichment around the coastline.
... Their study revealed a significant correlation between DIN and high abundance of certain diatom genera (e.g. Cocconeis), indicating the response of certain taxa to nutrient levels particularly along an eutrophication gradient (Agatz et al., 1999;Kafouris et al., 2019;Car et al., 2020). Although excluded in the current analyses, nutrients in the form of dissolved inorganic phosphorus and silicates are essential in microalgal growth and productivity, and tend to influence variation in diatom assemblages (Hafner et al., 2018;Kafouris et al., 2019;Car et al., 2020). ...
... Cocconeis), indicating the response of certain taxa to nutrient levels particularly along an eutrophication gradient (Agatz et al., 1999;Kafouris et al., 2019;Car et al., 2020). Although excluded in the current analyses, nutrients in the form of dissolved inorganic phosphorus and silicates are essential in microalgal growth and productivity, and tend to influence variation in diatom assemblages (Hafner et al., 2018;Kafouris et al., 2019;Car et al., 2020). Spatio-temporal nutrient availability and, in turn microalgal biomass, strongly aid in driving the dynamics of nearshore communities (Menge et al., 1997;Chatterjee et al., 2013). ...
... Tekwani et al., 2013) and marine waters (e.g. Hafner et al., 2018;Car et al., 2020). Taking into account the previous findings from a coastline-wide assessment (Cotiyane-Pondo et al., 2020), the extent of temperature as a causative factor at a small-scale (the current study) is particularly interesting and requires temporal monitoring given the high diurnal and seasonal temperature variability. ...
Marine epilithic diatom abundance and species richness are highly variable along the South African coastline. To determine the variability in spatial diversity and benthic-pelagic exchanges, we conducted a baseline study of the Bird Island ecosystem in Algoa Bay. Diatom samples were collected from the rocky substrate and the adjacent water column in conjunction with physico-chemical variables at five localities around the island. Species belonging to Achnanthes, Cocconeis, Licmophora and Navicula genera were found to be widely distributed around the island. Diatom species abundance and diversity varied around the island and a dominance of typically benthic species in the surf zone, coupled with a low abundance of truly planktonic species, was evident. The low number of planktonic diatoms in the water column and their absence in benthic samples in this study suggests an intertidal system driven largely by benthic diatoms. Elevated dissolved inorganic nitrogen (DIN), indicative of the guano influence from resident seabirds, along with temperature and turbidity, influenced the observed diatom composition and distribution. This study reveals an interplay between benthic and planktonic diatoms in the nearshore environment providing some insight into their contribution to the intertidal and subtidal foob web. It further provides important information for future comparisons of benthic diatoms on Bird Island in light of their ecological indicator properties under global environmental change scenarios for this region.
