Phosphorus enrichment of stream ecosystems generally increases primary production in the benthos, but the consequences of eutrophication for the nutritional quality of periphyton for grazers are less clear. On short time scales, high phosphorus inputs may lead to reduced C:P ratios and high essential fatty acid contents of periphyton, which are both considered important determinants of food quality

The marine red alga Porphyra umbilicalis has high tolerance towards various abiotic stresses. In this study, the contents of floridoside, isofloridoside and trehalose were measured using gas chromatography mass spectrometry (GC‐MS) in response to desiccation and rehydration treatments; these conditions are similar to the tidal cycles that P. umbilicalis experiences in its natural habitats. The GC‐MS

The taxonomic placement of strains belonging to the extremophilic red alga Galdieria maxima has been controversial due to the inconsistent phylogenetic position inferred from molecular phylogenetic analyses. Galdieria maxima nom. inval. was classified in this genus based on morphology and molecular data in the early work, but some subsequent molecular phylogenetic analyses have inferred strains of

Wild Microcystis have high diverse colonial structure and size, including variable colony geometry, cell arrangement, and diameter. These structural and dimensional variations may play an important role in continual, frequent Microcystis blooms during summer and autumn, the cause of which still remains unclear. Here, laboratory cultures and field investigations were applied to assess the variation

Harmful cyanobacterial blooms (CyanoHABs) are a rapidly proliferating global problem, threatening the use and sustainability of our freshwater resources. In recent decades, the USA, China and other developed and developing countries threatened by CyanoHAB expansion have developed collaborative efforts aimed at mitigating and managing this environmental and human health problem. However, an escalating

Species concepts formalize evolutionary and ecological processes, but often conflict with one another when considering the mechanisms that ultimately lead to species delimitation. Evolutionary biologists are, however, recognizing that the conceptualization of a species is separate and distinct from the delimitation of species. Indeed, if species are generally defined as separately evolving metapopulation

Giant clams harbor three genera of symbiotic dinoflagellates (Symbiodinium, Cladocopium , Durusdinium ) as extracellular symbionts (zooxanthellae). While symbiotic dinoflagellates can synthesize amino acids to benefit the host, they are nitrogen‐deficient. Hence, the host must supply them with nitrogen including urea, which can be degraded to ammonia and carbon dioxide by urease (URE). Here, we report

Carpopeltis maillardii has been regarded as a widely distributed species in the Indo‐Pacific region. In this study, we analyzed the genetic diversity of C. maillardii and related species collected from Taiwan and the Indian Ocean based on rbc L sequences, in order to elucidate species boundaries, diversity, and biogeographic patterns. Our analyses show that C. maillardii specimens are only distantly

Pyropia haitanensis (also named as Neoporphyra haitanensis ) is an economically important red seaweed that inhabitsupper intertidal zones. The thallus tolerates extreme fluctuating environmental stresses (e.g., surviving more than 80% water loss during low tides). To elucidate the global molecular responses relevant to this outstanding desiccation tolerance, a quantitative proteomics analysis of P

The genus Minidiscus comprises a group of ecologically‐important and globally‐distributed planktonic diatoms that are characterized by their small cell size, high mantle and processes more or less concentrated in the valve center. Monoclonal strains were established from collections along the Chinese coast. In the phylogenetic analyses inferred from a LSU and SSU dataset, six Minidiscus species clustered

To unlock the potential of Chlorella stigmatophora (Trebouxiophyceae, Chlorophyta) and Hemiselmis andersenii (Cryptophyceae, Cryptophyta) as natural reactors for biotechnological exploitation, their lipophilic extracts were characterized using Fourier Transform Infrared spectroscopy with Attenuated Total Reflectance (FTIR‐ATR) and Gas Chromatography‐Mass Spectrometry (GC‐MS) before and after alkaline

Marine heatwaves (MHWs) are emerging as forceful agents of ecosystem change and are increasing in frequency, duration and intensity with climate change. During MHWs, physiological thresholds of native species may be exceeded while the performance of invasive species with warm affinities may be enhanced. As a consequence, MHWs could significantly alter an ecosystems invasive dynamics, but such interactions

Species within the green algal order Cladophorales have an unconventional plastome structure where individual coding regions or small numbers of genes occur as linear single‐stranded DNAs folded into hairpin structures. Another group of photosynthetic organisms with an equivalently reduced chloroplast genome are the peridinin dinoflagellates of the Alveolata eukaryotic lineage whose plastomes are mini‐circles

The sensitivity of kelps to elevated temperatures has been linked to recent declines in some kelp populations, with cascading impacts on marine communities. However, it remains unclear how thermal stress affects the ability of kelps to respond to other environmental factors, which could influence their vulnerability to climate change. We investigated the effect of thermal stress on the ability of the

Photosynthetic dinoflagellates are ecologically and biogeochemically important in marine and freshwater environments. However surprisingly little is known of how this group acquires inorganic carbon or how these diverse processes evolved. Consequently, how CO2 availability ultimately influences the success of dinoflagellates over space and time remains poorly resolved compared to other microalgal groups

A partial rbc L sequence from the type material of Spongites discoideus from southern Argentina showed that it was distinct from rbc L sequences of South African specimens to which that name had been applied based on morpho‐anatomy. A partial rbc L sequence from an original syntype specimen, herein designated the lectotype, of Lithophyllum marlothii , type locality Camps Bay, Western Cape Province

Sea ice algae contribute up to 25% of the primary productivity of polar seas and seed large‐scale ice‐edge blooms. Fluctuations in temperature, salinity, and light associated with the freeze/thaw cycle can significantly impact the photophysiology of ice‐associated taxa. The effects of multiple co‐stressors (i.e., freezing temperature and high brine salinity or sudden high light exposure) on the photophysiology

Phytohormones are pivotal signaling compounds in higher plants, in which they exert their roles intracellularly, but are also released for cell‐to‐cell communication. In unicellular organisms, extracellularly released phytohormones can be involved in chemical crosstalk with other organisms. However, compared to higher plants, hardly any knowledge is available on the roles of phytohormones in green

In the last decade, the known biogeography of nitrogen fixation in the ocean has been expanded to colder and nitrogen‐rich coastal environments. The symbiotic nitrogen‐fixing cyanobacteria group A (UCYN‐A) has been revealed as one of the most abundant and widespread nitrogen‐fixers, and includes several sublineages that live associated with genetically distinct but closely related prymnesiophyte hosts

Molecular studies have reported the co‐existence of two species of Agarophyton in New Zealand: the newly described A. transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more wide‐spread A. chilense. Here we compared the distribution, genetic diversity, and structure of both Agarophyton species throughout the archipelago using sequences of the nuclear

Nereocystis luetkeana is a canopy‐forming kelp that exhibits morphological plasticity across hydrodynamic gradients, producing broad, undulate blades in slow flow and narrow, flattened blades in fast flow, enabling thalli to reduce drag while optimizing photosynthesis. While the functional significance of this phenomenon has been well studied, the developmental and physiological mechanisms that facilitate

Skeletonema marinoi is one of the most widely widespread marine planktonic diatoms in temperate coastal regions and sometimes can form massive blooms. Yet, the molecular mechanisms of triacylglycerol (TAG) synthesis in nutrient deficiency conditions for this species is still unknown. This study aimed to investigate how TAG biosynthetic pathway of S. marinoi reacts to the culture age and nitrogen (N)

The polyphasic approach has been widely applied in cyanobacterial taxonomy, which frequently led to additions to the species inventory. Increasing our knowledge about species and the habitats they were isolated from enables new insights into the ecology of newly established genera and species allowing speculations about the ecological niche of taxa. Here, we are describing three new species belonging

Morphological and molecular features were analyzed for a species of Phacus to better understand the phylogenetic relationships among them and establish the taxonomy. Phylogenetic analyses were based on nSSU rDNA and the research resulted in 55 new sequences. The study included species available in algal collections and those isolated directly from the environment in Poland and the Czech Republic. As

The subtidal kelp Nereocystis luetkeana (hereafter Nereocystis ) maintains an upright stature by producing a single gas‐filled float (pneumatocyst) that provides buoyancy. The ability of Nereocystis pneumatocysts to inflate with gas underwater is peculiar, and the gas composition of pneumatocysts has been the topic of several studies over the last 100 years. Past studies of pneumatocyst gases only

Nitric oxide (NO) is widely recognized as an important transmitter molecule in biological systems, from animals to plants and microbes. However, the role of NO in marine photosynthetic microbes remains unclear and even less is known about the role of this metabolite in Antarctic sea‐ice diatoms. Using a combination of microsensors, microfluidic chambers, and artificial sea‐ice tanks, a basic mechanistic

Microalgae exhibit extensive potential for counteracting imminent challenges in the nutraceutical, pharmaceutical, and biomaterial sectors, but lack economic viability. Biotechnological systems for contamination control could advance the economic viability of microalgal feedstock, but the selection of suitable strains that sustainably promote microalgal productivity remains challenging. In this study

A high proportion of the kelp Laminaria hyperborea production is exported from kelp forests following seasonal storms or natural annual old blades loss. Transport of drifting kelp fragments can lead to temporarily accumulations in benthic subtidal habitats. We investigated the degradation processes of L. hyperborea in a low subtidal sandy bottom ecosystem by setting up a six‐month cage experiment to

The poorly understood filamentous cyanobacterium Pseudanabaena is commonly epiphytic on Microcystis colonies and their abundances are often highly correlated during blooms. The response and adaptation of Microcystis to iron limitation have been extensively studied, but the strategies Pseudanabaena uses to respond to iron limitation are largely unknown. Here, physiological responses to iron limitation

In all, 26 cultures of the harmful marine dinoflagellate Karlodinium , isolated from Japanese and Philippine coastal waters, were examined using LM, SEM, and molecular phylogeny inferred from ITS and LSU rDNA. Seven Karlodinium species (six from Japan and four from Philippines), K. australe , K. ballantinum , K. decipiens , K. gentienii , K. veneficum , K. zhouanum , and a novel species Karlodinium

The determination of the ploidy level of an organism is a prerequisite for studies of evolution, cellular function, and genomic construction. Identification of the ploidy of the economically important red alga Gracilariopsis lemaneiformis has been hindered by its small genome and large number of chromosomes. Therefore, in the current study, PloidyNGS, a tool that calculates the number of reads supporting

Dissolved organic carbon (DOC) is an important source of carbon and energy for microbes, but whether it can be used by phytoplankton has not been systematically studied, and the underlying molecular metabolism remains poorly understood. Here, we investigated the ability of phytoplankton to utilize glycerol as a representative of DOC. The widespread presence and expression of glycerol transporter genes

ON THE COVER: A colonial chrysophyte Synura hibernica , composed by several elongated cells joined together by their posterior ends. Note the layer or imbricate silica scales covering the entire surface of the cells. This species has a striking distribution pattern, being quite common in North America but much less so in Europe where it occurs only in western Ireland.

We evaluated the life cycle of Leathesia marina through molecular analyses, culture studies, morphological observations, and ploidy measurements. Macroscopic sporophytes were collected from two localities in Atlantic Patagonia and were cultured under long‐day (LD) and short‐day (SD) conditions. Molecular identification of the microscopic and macroscopic phases was performed through the cox 3 and rbc

To test the proposal that rotifers release one or more chemical microalgal growth inhibitors in addition to devouring the microalgal cells, the effects of different concentrations of filtered, bacteria-free, rotifer culture filtrate (RCF) on the growth and physiological parameters of Chlorella sp., and the response of Chlorella sp. at different starting cell densities to 10% RCF were studied. The results

Membrane permeabilities to CO2 and HCO3− constrain the function of CO2 concentrating mechanisms that algae use to supply inorganic carbon for photosynthesis. In diatoms and green algae, plasma membranes are moderately to highly permeable to CO2 but effectively impermeable to HCO3−. Here, CO2 and HCO3− membrane permeabilities were measured using an 18O‐exchange technique on two species of haptophyte

Uptake dynamics of dissolved inorganic phosphate (DIP) and dissolved inorganic nitrate (DIN) in young Palmaria palmata (n  = 49), cultivated in a range of DIP concentrations (0.0–6.0 µmol · L−1) and nonlimiting DIN concentration (50 µmol · L−1) under fully controlled laboratory conditions, were quantified in a ‘pulse‐and‐chase’ approach over 5 weeks. Two different uptake rates were specified: (1) surge

Saccharina japonica is a brown macroalga that has been commercially cultivated in China for almost a century. As a natural raw material, it is widely used in the food and pharmaceutical industries, and it may potentially be useful for biofuel production. However, little is known about the genes involved in carbohydrate biosynthesis, and their regulation is less understood. In this study, the analysis

Lake snow, caused by the freshwater centric diatom Lindavia intermedia , has become problematic in several large, oligotrophic New Zealand lakes over the past decade. Macroaggregates produced by L. intermedia foul fishing lines, intake screens, and water filters, and have a negative impact on recreational values. It was confirmed that the fibers constituting lake snow are composed of chitin, two chitin

Ceratium furcoides is an invasive freshwater dinoflagellate that in the last three decades has expanded its geographic distribution in South America, being recently found in Paraná River floodplain (Argentina). Despite growing concern about the presence and impacts of this invader, information regarding genetic diversity in the Southern Hemisphere is missing. This work constitutes the first phylogenetic

The cosmopolitan red algal genus Pyropia sensu lato is the most speciose of the bladed Bangiales genera. In a major revision of the Bangiales, Pyropia was resurrected from Porphyra, although there was evidence at the time that species of Pyropia could be separated into several genera. Subsequent global phylogenetic analyses continued to resolve species assigned to Pyropia into several major clades

The uptake and conversion of a free-living cyanobacterium into a photosynthetic organelle by the single-celled Archaeplastida ancestor helped transform the biosphere from low to high oxygen. There are two documented, independent cases of plastid primary endosymbiosis. The first is the well-studied instance in Archaeplastida that occurred ca. 1.6 billion years ago, whereas the second occurred 90-140

Since the first phylogenetic study of the order Batrachospermales, Batrachospermum was shown to be paraphyletic. Subsequently, sections of the genus have been methodically investigated using DNA sequences and morphology in order to propose new genera and delineate species. Batrachospermum section Turfosa is the last section with multiple species yet to be examined. New sequence data of specimens from

A pink to red-pigmented cryptophyte of undetermined taxonomic affinity was isolated and cloned from two seasonally ice-covered. meromictic, saline Antarctic aquatic environments: Bayly Bay (BB) and Ace Lake (AL). The clones shared a number of morphological and ultrastructural similarities with other cryptomonad genera, which confounded identification by light and electron microscopy. Cellular pigments

The Arctic Ocean is a unique ecosystem hosting a biodiversity that has not yet been elucidated in full detail. There is increasing evidence that there are more kelp species constricted to Arctic/sub-Arctic habitats hitherto not well investigated, such as Hedophyllum nigripes, which is morphologically very similar to cold-temperate Laminaria digitata. Hedophyllum nigripes was originally described as

The eukaryotic green microalga Tetraselmis suecica is commonly used for aquaculture purposes because of its high stress tolerance and ease of culture in a wide spectrum of environments; they are therefore suitable candidates for biotechnology applications. To date, no data are available regarding chloroplast transformation vectors based on specific endogenous promoters and homologous targeting regions

The Symbiodiniaceae are a family of marine dinoflagellates known mostly for their endosymbiotic interactions with invertebrates and protists, but facultatively and exclusively free-living life histories in this family are also evident. A recent systematic revision of the Symbiodiniaceae replaced the clade-based nomenclature of seven divergent lineages of "Symbiodinium" sensu lato with one based on

Worldwide, macroalgae have invaded near-shore marine ecosystems. However, their haplodiplontic life cycles have complicated efforts to predict patterns of growth and spread, particularly since most theoretical predictions are derived from diplontic taxa (i.e., animals). To complete one revolution of the life cycle, two separate ploidy stages, often including separate haploid sexes, must pass through

The biological processes involved in the preservation, viability, and revival of long‐term dormant dinoflagellate cysts buried in sediments remain unknown. Based on studies of plant seed physiology, we tested whether the revival of ancient cysts preserved in century‐old sediments from the Bay of Brest (France) could be stimulated by melatonin and gibberellic acid, two molecules commonly used in seed

Geographic variation of phenotypic traits affects the capacity of species to withstand and adapt to environmental stress. Here, we examined how geographic origin influences UV stress tolerance of the red seaweeds Chondracanthus chamissoi and Gelidium lingulatum distributed along the South‐East Pacific coast between 20° S and 42° S. Seaweeds from six (C. chamissoi ) and five (G. lingulatum ) populations

Detailed morphological documentation is provided for established Proschkinia taxa, including the generitype, P. bulnheimii, and P. complanata, P. complanatula, P. complanatoides and P. hyalosirella, and six new species. All established taxa are characterized from original material from historical collections. The new species described in this paper (P. luticola, P. staurospeciosa, P. impar, P. modesta

Sargassum horneri is a habitat-forming species in the Northwest Pacific and an important contributor to seaweed rafts. In this study, 131 benthic samples and 156 floating samples were collected in the Yellow Sea and East China Sea (ECS) to test the effects of seaweed rafts on population structure and connectivity. Our results revealed high levels of genetic diversity in both benthic and floating samples

The domesticated marine microalga Diacronema lutheri is of great interest for producing various highly valuable molecules like lipids, particularly long-chain polyunsaturated fatty acids (LC-PUFA). In this study, we investigated the impact of phosphorus (P) and nitrogen (N) starvation on growth, carbon fixation (photosynthetic activity) and partitioning, and membrane lipid remodeling in this alga during

Comparative organelle genome studies of parasites can highlight genetic changes that occur during the transition from a free-living to a parasitic state. Our study focuses on a poorly studied group of red algal parasites, which are often closely related to their red algal hosts and from which they presumably evolved. Most of these parasites are pigmented and some show photosynthetic capacity. Here

With the advent of more comprehensive research into the microbiome and interactions between animals and their microbiota, new solutions can be applied to address conservation challenges such as husbandry and medical care of captive animals. Although studies on epizoic algae are relatively rare, and the function and role of those mainly photosynthetic organisms in the animal microbiome is not well understood

The main aims of this work were to assess phylogenetic relationships of the trentepohlialean photobionts in tropical, mainly sterile, lichens collected in Bolivia, to examine their genetic diversity, host specificity, and the impact of habitat factors on the occurrence of Trentepohliales. Based on rbcL marker analysis, we constructed a phylogenetic tree with eight major clades of Trentepohliales, of

Samples of Pithophoraceae, collected in diverse freshwater and damp terrestrial habitats from tropical and subtropical China, were characterized morphologically and ultrastructurally, and their phylogenetic position was determined based on nuclear ribosomal DNA sequences. Our phylogenetic analysis resolved a novel lineage of Pithophoraceae, sister to Aegagropilopsis. Based on our phylogenetic results

We assessed the relative influence of ecoregional features in explaining diatom distribution in the Orinoco river basin. Ecoregions in the Colombian Orinoco can be seen as imprints of the evolutionary history of the basin, for their current biodiversity and physiographic features are the result of the geological and climatic shifts that have occurred since the Tertiary. Thus, they represent an ideal

Populations of many Mediterranean marine species show a strong phylogeographic structure, but the knowledge available for native seaweeds is limited. We investigated the genetic diversity of the green alga Halimeda tuna based on two plastid markers (tufA gene and a newly developed amplicon spanning five ribosomal protein genes and intergenic spacers, the rpl2-rpl14 region). The tufA sequences showed

Mixotrophic algae that combine photoautotrophy with phagotrophy in a single cell are prevalent in marine ecosystems. Here, we assessed the ability of food ingestion in coccolithophores, an important group of calcifying haptophytes inhabiting the oceans. We tested four species from different coccolithophore lineages (Emiliania huxleyi, Calcidiscus leptoporus, Coccolithus braarudii, and Calyptrosphaera