Algal Species Diversity Research Articles

Understanding diversity-synchrony-stability relationships in multitrophic communities.

Understanding how species loss impacts ecosystem stability is critical given contemporary declines in global biodiversity. Despite decades of research on biodiversity-stability relationships, most studies are performed within a trophic level, overlooking the multitrophic complexity structuring natural communities. Here, in a global analysis of diversity-synchrony-stability (DSS) studies (n = 420), we found that 74% were monotrophic and biased towards terrestrial plant communities, with 91% describing stabilizing effects of asynchrony. Multitrophic studies (26%) were representative of all biomes and showed that synchrony had mixed effects on stability. To explore potential mechanisms, we applied a multitrophic framework adapted from DSS theory to investigate DSS relationships in algae-herbivore assemblages across five long-term tropical and temperate marine system datasets. Both algal and herbivore species diversity reduced within-group synchrony in both systems but had different interactive effects on species synchrony between systems. Herbivore synchrony was positively and negatively influenced by algal diversity in tropical versus temperate systems, respectively, and algal synchrony was positively influenced by herbivore diversity in temperate systems. While herbivore synchrony reduced multitrophic stability in both systems, algal synchrony only reduced stability in tropical systems. These results highlight the complexity of DSS relationships at the multitrophic level and emphasize why more multitrophic assessments are needed to better understand how biodiversity influences community stability in nature.

Benthic Algal Assemblages Associated with Damselfi sh Territories in The Gulf of Thailand

Territorial damselfi sh are herbivorous fi sh that help maintain algal diversity and abundance by aggressive territorial defense and algal farming. We investigated the effect of territorial damselfi sh on algal diversity and abundance on a reef at Ko Taen, Surat Thani Province, Thailand. Ten permanent patches (20 × 20 cm2) were set up inside and ten outside damselfi sh territory and monitored bimonthly. We found 22 macroalgal species with fi ve dominant species: Polysiphonia sp., Padina minor, Ulva compressa, Gelidium pusillum, and Lobophora variegata. The abundance of Polysiphonia sp. was signifi cantly higher inside damselfi sh territory than outside. In contrast, the abundances of Gelidium pusillum, Padina minor, and Ulva compressa were slightly higher outside the territory. It might be perhaps because their feeding behavior, territorial defense, and farming activities altered the benthic community. These damselfi shes exclude other herbivorous fi shes from their territories and remove unpalatable algae and maintain their algal food crop. For species diversity, there was no signifi cant difference between algal species diversity outside and inside damselfi sh territories. Our results indicated that damselfi shes have a strong effect on algal abundance and composition.

Comprehensive analysis of harmful algal blooms in indonesia: from occurrence to impact

The occurrence and frequency of harmful algal blooms have become a significant problem in Indonesia's coastal waters since 1991. This article aims to thoroughly analyze the diversity of algal species involved in these harmful algal blooms (HABs). It highlights that some algae, such as toxic species, can produce dangerous toxins, while others, such as non-toxic algae, remain harmless. This article reviews research studies that describe the occurrence, frequency, and causative types of bloom events in several contaminated coastal regions of Indonesia. The blooms had many consequences for fisheries, the aquatic environment, the economy, and public health. Among the identified species, Pyrodinium bahamense var. compressum is known for its high toxicity. The most common taxa contributing to bloom tragedy are Chaetoceros, Noctiluca, and Skeletonema. The study recognizes that human-induced nutrient enrichment is a major and significant factor in triggering the bloom phenomena. The paper recommends various management strategies and further research initiatives to prevent and reduce the impacts of HABs in Indonesia.

Metabarcoding analysis identifies high diversity of harmful algal bloom species in the coastal waters of the Beibu Gulf.

Harmful algal blooms (HABs) have occurred more frequently in recent years. In this study, to investigate their potential impact in the Beibu Gulf, short-read and long-read metabarcoding analyses were combined for annual marine phytoplankton community and HAB species identification. Short-read metabarcoding showed a high level of phytoplankton biodiversity in this area, with Dinophyceae dominating, especially Gymnodiniales. Multiple small phytoplankton, including Prymnesiophyceae and Prasinophyceae, were also identified, which complements the previous lack of identifying small phytoplankton and those unstable after fixation. Of the top 20 phytoplankton genera identified, 15 were HAB-forming genera, which accounted for 47.3%-71.5% of the relative abundance of phytoplankton. Based on long-read metabarcoding, a total of 147 OTUs (PID > 97%) belonging to phytoplankton were identified at the species level, including 118 species. Among them, 37 species belonged to HAB-forming species, and 98 species were reported for the first time in the Beibu Gulf. Contrasting the two metabarcoding approaches at the class level, they both showed a predominance of Dinophyceae, and both included high abundances of Bacillariophyceae, Prasinophyceae, and Prymnesiophyceae, but the relative contents of the classes varied. Notably, the results of the two metabarcoding approaches were quite different below the genus level. The high abundance and diversity of HAB species were probably due to their special life history and multiple nutritional modes. Annual HAB species variation revealed in this study provided a basis for evaluating their potential impact on aquaculture and even nuclear power plant safety in the Beibu Gulf.

Diversity and Ecological Characteristics of Algae in the Water Column in the Subbasin of the Large Danube Lakes During the Autumn-Winter Period (Ukraine)

The paper deals with structural and functional components of algal diversity and ecological characteristics in the water column of the large Danubian lakes, Kahul, Kartal, Yalpuh, Kuhurluy, Katlabukh, and Kytay, in the late autumn-winter of 2019-2020. The water column algal taxonomic diversity comprised of 188 species, represented by 191 infraspecies taxa from 7 divisions, 14 classes, 30 orders, 61 families, and 108 genera. According to the algal species diversity, the lakes can be put in the following order: the Yalpuh (78) > Kytay (76) > Kahul (75) > Kuhurluy (55) > Katlabukh (23) > Kartal (16 ist) Bacillariophyta, <i>Chlorophyta</i> and <i>Cyanobacteria</i> prevailed. According to habitat preference, planktonic forms made up 45%, benthic forms 24%, epiphytic forms 5%, littoral forms 15%, and eurytopic forms 11%. According to salinity preference indifferent species dominated, and according to pH preference alkaliphilic species prevailed. The Sorensen similarity index and Kendall rank correlation indices for leading families were rather low -0.18-0.43 and 0.45-0.57, respectively, which is indicative of significant differences among the algal communities in the lakes under study. The algal cell count amounted to 2,853-360,325 thousand cells · dm<sup>-3</sup>, the biomass - 0.876-64.113 g · dm<sup>-3</sup>. According to the quantitative characteristics of planktonic algal communities and <i>Cyanobacteria</i> biomass, the Danubian lakes are eutrophic.

TAXONOMY, DISTRIBUTION AND DIVERSITY OF PLANKTONIC ALGAE AT PINDIGA DAM, NIGERIA

Taxonomic identification of algae at both generic and species levels is problematic owing to several reasons including cells’ fragility, sensitivity to chemical fixatives and inconspicuous morphological features. The planktonic algae in tropical African dams have been particularlyproblematic given the paucity of algal taxonomic experts in this region. In this study, we presentfor the first time the taxonomic and geographic appraisal of planktonic Algae at Pindiga Dam. Further, planktonic algal flora and its monthly variations at the Pindiga Dam were investigated. The study revealed a total of 35 genera. Species in the family Chlorophyceae were the most abundant (42%), followed by those in the families Bacillariophyceae (38%) and Charophyceae(25%). Other taxonomic groups present were Chryophyceae, Cryptophyceae, Cynophyceae and Euglenophyta (7%) each. Trachelomonas, Tetrahedrom and Pleurozester were the most abundant taxa. The Important Value Index (IVI) and species diversity of algae are dependent on the sampling month. For instance, Trachelomonas recorded the highest IVI (23.67) and thelowest was recorded by Cryptomonas (8.18) in April, but it was observed that in May; Tetrahedrom recorded the highest IVI (22.57) and the lowest was recorded by Zygnema (9.38). In June, another set of taxa recorded the highest and the Lowest IVI namely: Pleurogaster, Crucigenia (17.63) and Netrium, Oedogenium (8.93) each. The composition of planktonic algae families in Pindiga Dam could be said to be Chlorophyceae, Bacillariophyceae, and Cyanophyceae in order of the IVI. The Simpson’s index of diversity of planktonic algae at Pindiga Dam was 0.94542, 0.94708 and 0.95364 in April, May and June respectively. The species richness in April was 1.97, in May was 1.92 and in June was 2.10. The values were high indicating a more complex plankton community with a good measure of abundance and diversity. This study has provided baseline information on the taxonomy, distribution and diversity of planktonic algae in Pindiga Dam. This knowledge is useful to groups involved in water utilities; irrigation and drainage districts, industries, private pond owners, fish farmers and aqua culturist.

Biotechnological Enhancement of Probiotics through Co-Cultivation with Algae: Future or a Trend?

The diversity of algal species is a rich source of many different bioactive metabolites. The compounds extracted from algal biomass have various beneficial effects on health. Recently, co-culture systems between microalgae and bacteria have emerged as an interesting solution that can reduce the high contamination risk associated with axenic cultures and, consequently, increase biomass yield and synthesis of active compounds. Probiotic microorganisms also have numerous positive effects on various aspects of health and represent potent co-culture partners. Most studies consider algae as prebiotics that serve as enhancers of probiotics performance. However, the extreme diversity of algal organisms and their ability to produce a plethora of metabolites are leading to new experimental designs in which these organisms are cultivated together to derive maximum benefit from their synergistic interactions. The future success of these studies depends on the precise experimental design of these complex systems. In the last decade, the development of high-throughput approaches has enabled a deeper understanding of global changes in response to interspecies interactions. Several studies have shown that the addition of algae, along with probiotics, can influence the microbiota, and improve gut health and overall yield in fish, shrimp, and mussels aquaculture. In the future, such findings can be further explored and implemented for use as dietary supplements for humans.

Algae and cyanobacteria in soils polluted with heavy metals (Northwest Russia, Murmansk region)

The analysis of algae and cyanobacteria in Albic Podzols affected by emissions of the copper–nickel plant Pechenganikel in the forest-tundra of the Arctic region was carried out. The main pollutants contained in the emissions and entering the soil are sulfur compounds and heavy non-ferrous metals. Algae and cyanobacteria were identified in soil samples collected in three zones differing in their distance from the pollution source: the zone of strong pollution (at a distance of 3 km southwest from the source of the emission), the zone of medium pollution (5-7 km), and the zone of weak pollution (16-25 km). In total, 61 species of eukaryotic algae and 2 species of cyanobacteria were found. In the studied soils, several species of algae were found with a high frequency, apparently resistant to unfavorable natural and anthropogenic factors: Chloromonas sp., Neocystis brevis, Parietochloris alveolaris, Pseudococcomyxa simplex, Stichococcus bacillaris, Interfilum terricola, Leptosira cf. obovata, Myrmecia bisecta, Nostoc muscorum. Algae from the Chlorophyta division predominated in all soils studied. Yellowgreen algae and diatoms were found only in the zone of strong pollution and were represented by a very small number of species. The presence of Microthamnion kuetzingianum, which is resistant to high acidity and heavy metals concentration, can be useful as an indicator of severe heavy metal contamination. Our study confirmed sensitivity of Vischeria magna to soil contamination with heavy metals. In long-term aspect, the species diversity of algae has increased by 35% in the soils influenced by the Pechenganikel plant in comparison with the data obtained 30 years ago, which probably indicates a certain decrease in anthropogenic load on the adjacent territories.

Ecological and taxonomic structure of winter algocoenosis in the rivers of the Sevastopol region

The paper considers the ecological and taxonomic structure of the winter algocoenosis of the Chernaya, Kacha, and Belbek rivers within the territory of the city of Sevastopol. The results of studies were obtained on 30 chemical and physical parameters of surface water samples during the period of algological sampling. The collection of field material (phytoplankton, algae in fouling, on various substrates immersed in water) and its processing was carried out according to the methods generally accepted in algological practice. The diagnostic features, as well as the similarities and differences in the species diversity of algae, have been determined. The studies carried out show that the studied algocoenosis are characterized in winter period by a rich species composition, with a significant predominance of diatoms. The algae found in the studied rivers are indicators of water purity, and their occurrence activity and abundance can indicate that the content of organic matter in the waters of the Belbek and Kacha rivers is lower than in the Chernaya river. This is confirmed by the presence of algae xenosaprobionts in the waters of the Belbek and Kacha rivers, which are indicators of clean, not polluted, with organic substances water.

Sea-ice, primary productivity and ocean temperatures at the Antarctic marginal zone during late Pleistocene

While Pleistocene glacial-interglacial cycles are commonly associated with strong waxing and waning of Northern Hemisphere ice sheets, the response of the Antarctic ice sheet and regional changes in oceanographic and environmental conditions to Pleistocene climate dynamics remain poorly constrained. We present a reconstruction of sea-ice cover, sea surface temperature and primary productivity off the Ross Sea margin (Adare Basin at the slope of the Drygalski Basin) during the marine isotope stages (MIS) 9 to 5 (350–70 thousands years ago, encompassing Terminations IV to II). Our multiproxy study relies on micropaleontology (diatoms, dinoflagellate cysts, benthic foraminifers), organic and inorganic geochemistry proxies (carbon and nitrogen isotopes, lipid biomarkers, XRF-data), and sedimentology (IRD) obtained from deep-sea core AS05-10. For each glacial-interglacial transition a clear succession of events can be observed: (near-)permanent sea ice cover during glacial stages is followed by ice-shelf break-up with episodic ice-free areas and surface water stratification. Notably, ice-shelf break-up precedes the increase in air temperature as measured in the Vostok ice core for each glacial-interglacial transition. Generally, air temperature over Vostok starts rising once sea-ice cover at site AS05-10 has significantly decreased, becoming seasonal, as indicated by the diatom species composition. This is also reflected by the high diatom productivity and increased water mixing at site AS05-10, which is indicative of its proximity to the Marginal Ice Zone. At the onset of Termination II (MIS6 to 5), high export productivity and dysoxic bottom water conditions occurred, while water temperature increased about 5 °C. During each interglacial spring/summer sea-ice cover is most reduced, and highest productivity occurs. Following each interglacial, the warm and cold fluctuations match the sawtooth character of the temperatures over Vostok. This record illustrates that at the Ross Sea margin, sea surface conditions and (export) productivity were strongly influenced by the natural climate variability of the Pleistocene. In light of this, current global warming may lead to increased ice-shelf break-up, water column stratification and shifts in the position/size of the Marginal Ice Zone with implications for algal species composition and diversity, and for primary productivity.

Subtidal macrophyte diversity and potentials in Nha Trang Bay - baseline data for monitoring a rising natural resource

Tropical coastal ecosystems provide a unique complex marine habitat with a high diversity of algal species, Viet Nam being a particular hotspot. These algae may host a variety of potential unknown or underestimated bioactive algal compounds. In parallel the worldwide rising interest in macroalgae-based products leads to increasing activities in seaweed natural harvest and mariculture within coastal waters. With this growing interest, the present work provides baseline data for a systematic and science-based macroalgal monitoring program in Nha Trang Bay, Viet Nam, to keep track of potentially interesting taxa and to identify driving environmental factors which may also naturally influence biodiversity and species abundance. The present study investigated macrophyte diversity and abundance by combining a qualitative and quantitative macroalgal survey approach with environmental sampling (e.g. physicochemical properties of water column, underwater light regime, and sediment characteristics). Surveys were performed in the dry season (May/June) 2019 in different water depths (3, 6 and 10 m) at seven sites within Nha Trang Bay. The study revealed a coastal patchwork of diverse habitats inhabited by complex macrophyte communities, including estuarine dense Sargassum forests and Turbinaria meadows, sheltered sandy seagrass (Halodule spp.) beds with upcoming Lyngbya blooms, low diverse Padina deserts and highly turbid aquaculture (lobster and fish farms) impacted sites with surprisingly high macroalgal diversity. During our study a total of 86 macrophyte species were encountered in the subtidal (>1 m water depth), whereas only 6 species (Padina australis, Sargassum mcclurei, Turbinaria ornata, Halimeda discoidea, Amphiroa fragilissima, Tricleocarpa cylindrical) were frequently found at every survey site. The observed high patchiness and presence of economically important (e.g. Sargassum spp., Gracilaria spp., Caulerpa spp., Gelidiella acerosa, Acanthophora spicifera) and potentially economically interesting (e.g. Padina australis, Turbinaria ornata, Stypopodium zonale, Chondria armata) taxa during the survey underlines the high potential of the present macrophytic bio-resource, which apparently is strongly structured and will be altered by the changing heterogenic environment.

Assessment of small water bodies Sergiev Posad district on the taxonomic diversity of green, blue-green and diatom algae

The purpose of the study was to determine the degree of saprobity of the artificial extension of the Vytravki riverbed (left tributary of the Dubna river) in the Sergiev Posad district of the Moscow region, based on the taxonomic composition of the pelagial and littoral algal flora. For this purpose, the systematic position of algae was determined using a number of domestic and foreign sources, as well as using the electronic database AlgaeBase. The most attention was paid to common indicator types, according to the literature data. Algological samples were taken in accordance with generally accepted methods; the main part of the samples was processed immediately after collection on site, the rest of the material was fixed with a formalin solution and Prat medium for detailed study in laboratory conditions under a microscope. According to the results of the study of hydrobiological samples, the composition of algal flora in the summer-autumn period was determined. There is a large species diversity of algae, represented by most of the divisions characteristic of the Central part of Russia. The green, diatomaceous, and blue-green algae divisions were the most represented. Maximum species diversity was observed for the genera Scenedesmus (9 species) and Pediastrum (10 species). Diatoms are the second group in terms of frequency of occurrence of species that live both in standing water and in rheophilic conditions. Blue-green algae were represented by pelagic forms, with a small frequency of occurrence. Among them, the genera Anabaena (5 species) and Microcystis (3 species) are notable for their high species diversity. The algal flora of the pond was marked divisions, dinophyceae and kropotova, typical for oligotrophic and distrophic reservoirs, indicating a high quality water environment. The established hydrochemical parameters of the reservoir were normal and were similar to the reservoirs of Central Russia at the end of the growing season, which were not exposed to anthropogenic impact.

Mass developments of Euglena sanguinea Ehrenberg in South Africa

Blooms of Euglena sanguinea Ehrenberg were observed at two different locations in South Africa, Mpumalanga province during 2016 and Limpopo province during 2020. Besides being responsible for a blood-red discolouration of the water, the species is also toxic, causing fish mortalities. Samples from South Africa were dominated by E. sanguinea and very low concentrations and diversity of other algal species were present. Microscopic studies revealed that the size ranges and the morphology of the cells corresponded to descriptions of the species in literature. High quality micrographs, illustrating the general cell structure and most features used for accurate identification, are provided. Intensive literature searches allowed mapping of the worldwide geographical distribution of the species, which revealed that it was sparsely distributed throughout Africa, because it was reported from only seven countries. Only one previous record of its presence in experimental ponds in South Africa exists, rendering this study a second record for its presence in the country.

Management of Enteric Methanogenesis in Ruminants by Algal-Derived Feed Additives

In this paper, we critically review the current state of nutritional management strategies to reduce methane emissions resulting from enteric fermentation in livestock production. In this context, it highlights the novel strategy regarding the use of macroalgal- and microalgal-derived feed additives. Several feed management strategies for ruminants focus on the inclusion of nutritional supplements, increasing proportion of starch, or supplementation with high-energy lipids. These strategies aim to improve animal productivity, whilst at the same time reduce methane emissions. Algae supplements are currently investigated as novel ingredients for decreasing methanogenesis, with the potential production of algal biomass also contributing to reducing greenhouse gas emissions. Thus, utilisation of algal biomass as a feed concentrate in dietary supplementation presents a sustainable and environmentally friendly strategy. This review summarises the current stage of research on dietary strategies and their influences on the metabolic processes during enteric fermentation. This information is essential for developing strategies to mitigate methane emissions in the livestock industry. We specifically present the opportunities that algae could offer as a feed additive for methanogenic reduction in cattle. The data compiled from the peer-reviewed literature revealed synergistic effects of algal biomass on methane reduction and animal productivity. However, the challenges regarding the mass cultivation of macro- and microalgae were noticed. Considering the diversity of algal species, future research should increase screening efforts to include more species and dosage evaluation, along with efforts to see if such effects are sustained over time.

Assessment of diversity and physico-chemical parameters of cyanobacteria, diatoms and other algal species in the paddy fields of Belagavi district, Karnataka

Algae are the diverse group of organisms in the soil and aquatic environment. The role of them in soil fertility enhancement has been extensively studied worldwide. Belagavi is a tropical agricultural belt in the North Karnataka region with highly fertile soil. Water and soil samples were collected randomly from the paddy field of 15–20 well-distributed spots in 4 selected locations viz Kusumali, Jamboti, Kinaye and Piranwadi. The identification revealed the presence of 94 species and 71 genera in the investigated sites. Among all, 62 species belonged to Bacillariophyceae, 14 species to Chlorophyceae, 10 species to Cyanophyceae, 3 to Xanthophyceae, followed by Trebouxiophyceae and Zygnematophyceae (2 species each) and one species of Ulvophyceae. The maximum number of 62 species was recorded from Kusamali, followed by 49 species in Kinaye, 44 in Jamboti and 35 in Piranwadi. The month of February had the highest number of species (61), decreased to 45 in March, 42 in April and 37 in May. Among the physicochemical parameters analysed for the soil samples, it was found that the pH of the soil is slightly acidic in all the study sites ranged between 5.03–5.85. Further, the electrical conductivity (EC) varied from 0.27–0.345 dS/m, found to be in a good range. Estimation of available micro and macronutrients of soil were measured, and it was found to be at low to moderate levels. The present study indicates the extensive distribution of different classes of algae in the rice fields of four study locations in Belagavi.

Anti-inflammatory effects of peptides from a marine algicolous fungus Acremonium sp. NTU492 in BV-2 microglial cells.

Located in tropical and subtropical region, Taiwan is an island with high algal species diversity. In this study, a number of fungal strains were isolated from marine macroalgae collected from northeastern intertidal zone of Taiwan. Preliminary anti-inflammatory screening has shown that the methanolic extracts of solid fermented products of the red alga Mastophora rosea-derived fungal strain Acremonium sp. NTU492 exhibited significant bioactivity. In an attempt to disclose the active principles from this fungal strain, a series of separation and purification was thus undertaken, which has led to the isolation and characterization of seven compounds including four new peptides, namely acrepeptins A–D (1–4), along with previously reported destruxin B (5), guangomide A (6), and guangomide B (7). Their structures were elucidated by spectroscopic analysis and compared with literatures. Of these, acrepeptins A (1) and C (3) showed markedly inhibitory activities on nitric oxide production in lipopolysaccharide-activated microglial BV-2 cells with IC50 values of 12.0 ± 2.3 and 10.6 ± 4.0 μM, respectively. Furthermore, acrepeptins A (1) and C (3) significantly attenuated the expression of inducible nitric oxide synthase in a concentration-dependent manner (5–40 μM).

Molecular Assessment of the Tribes Streblocladieae and Polysiphonieae (Rhodomelaceae, Rhodophyta) in the British Isles Reveals New Records and Species that Require Taxonomic Revision

The use of molecular tools often shows that regional species diversity differs from what we know from assessments based on morphological identifications. The seaweed flora of the British Isles has been well established over a long period from foundational work published during the XVIII-XIX centuries to more recent revisions based on molecular tools. The application of these tools (primarily rbcL sequences), alongside morphological observations, to the study of the tribes Streblocladieae and Polysiphonieae in the British Isles led us to three new records of species, as well as two species that require taxonomic revision. Polysiphonia morrowii Harvey, P. delicata Diaz-Tapia and Vertebrata tripinnata (Harvey) Kuntze are recorded for the first time in the British Isles. Finding P. morrowii and P. delicata, which are considered introduced or cryptogenic in Europe, is not surprising and these new records improve our knowledge of their distribution. Vertebrata tripinnata had previously been recorded in southern Europe and collecting it on the northern coast of Ireland considerably expands its known distribution. We also found that rbcL and cox1 sequences for the morphologically divergent V. simulans (Harvey) Kuntze and P. ceramiiformis P.Crouan & H.Crouan (which has never been transferred to Vertebrata) from the British Isles were identical, and we propose to reduce the latter to a synonym of the former. Finally, we found two pseudo-cryptic species represented in specimens morphologically assigned to V. fruticulosa (Wulfen) Kuntze, and we propose the resurrection of V. martensiana (Kutzing) Pineiro-Corbeira, Maggs & Diaz-Tapia. This work further evidences the relevance of reassessing red algal species diversity using molecular tools, even in regions where floras are considered well-known.

Effect of habitat type on algal species diversity and distribution at high altitudes

To investigate how habitat type influences species diversity and distribution of algae, 115 sampling sites across eight different habitats (stream, spring, lake, pool, wetland, ditch, trough, hot-spring) were randomly sampled from Ağrı province, Turkey. A total of 392 algal taxa (gamma diversity) were identified, of which 212 taxa (54.08%) belonged to Bacillariophyta while the rest (180 taxa) belonged to seven other groups (Chlorophyta, Charophyta, Euglenophyta, Cyanobacteria, Miozoa, Ochrophyta, and Cryptophyta). 150 taxa were encountered only once. The highest alpha diversity was found in ditches (H' =4.57, 235 taxa) followed by streams (H' = 4.40, 238 taxa), and the lowest diversity was recovered in troughs (H' = 2.62, 42 taxa). Relatively high Whittaker's beta diversity (Bw = 19) indicated a low level of similarity among sampling sites suggesting that no common taxonomic group was solely effective enough to change dominancy level of any species among the habitats. The first two axes of Canonical Correspondence Analysis accounted for 58.1 % of the total variance in the occurrence of 152 algal taxa (all taxa recovered from more than three samples) and described gradients across four environmental variables (habitat type, pH, elevation and water temperature). Ditches significantly contribution to alpha and gamma diversity in the province although they have relatively small surface area and shallow water compared to other habitat types. High alpha diversity in ditches may be related to the positive effect of geographic and climatic factors in mountainous area. Future possibilities are discussed.

Influence of ecological factors on soil algae in different types of mountain tundra and sparse forests in the Northern Urals

ABSTRACT We studied how ecological factors affect species composition and structure of soil algal assemblages in different types of mountain tundra and sparse forests in the Northern Urals. Soil moisture, pH, nitrogen content and amount of solar radiation were determined using Ellenberg indicator values from phytoindicators. Species identification of soil algae was made using light microscopy following algal culture. We identified 74 algal species from five divisions. Most species were Cyanobacteria and Chlorophyta. For each habitat type we identified species with high frequency and fidelity. Algal species diversity was maximal in herbaceous plant communities, minimal in lichen communities, and showed a positive correlation with soil moisture and nitrogen content.

Excess of nitrogen reduces temporal variability of stream diatom assemblages

Nutrient enrichment degrades water quality and threatens aquatic biota. However, our knowledge on (dis)similarities in temporal patterns of biota among sites of varying level of nutrient stress is limited. We addressed this gap by assessing temporal (among seasons) variation in algal biomass, species diversity and composition of diatom assemblages in three streams that differ in nutrient stress, but are otherwise similar and share the same regional species pool. We monitored three riffle sections in each stream bi-weekly from May to October in 2014. Temporal variation in water chemistry and other environmental variables was mainly synchronous among riffles within streams and often also among streams, indicating shared environmental forcing through time. We found significant differences in diatom assemblage composition among streams and, albeit less so, also among riffles within streams. Diatom assemblages in the two nutrient-enriched streams were more similar to each other than to those in the nutrient-poor stream. Taxa richness did not differ consistently among the streams, and did not vary synchronously at any spatial scale. Temporal variation in diatom assemblage composition decreased with increasing DIN:TotP ratio, likely via a negative effect on sensitive taxa while maintaining favorable conditions for certain tolerant taxa, irrespective of season. This relationship weakened but remained significant even after controlling for stochastic effects, suggesting deterministic mechanisms between nutrient levels and diatom assemblage stability. After controlling for stochastic effects temporal variability was best explained by DIN suggesting that excess of nitrogen reduces temporal variability(intra-annual beta diversity) of diatom assemblages. The high temporal variation, and especially the lack of temporal synchrony at the within streams scale, suggests that single sampling at a single site may be insufficient to reliably assess and monitor a complete stream water body. Our results also showed that measures including species identity outperform traditional diversity metrics in detecting nutrient stress in streams.