Macroscopic Green Algae Research Articles

Natural attenuation of metals by algal mat from acid mine drainage at Malanjkhand copper mine

Filamentous macroscopic green algae are observed in acidic (pH 4.47–5.75) and metal-enriched discharges from the Malanjkhand copper mine (India), which is the largest one in Asia. The genuses of the algae are identified as Microspora and Ulothrix. The Microspora occurs as the most dominant one and thrives in wide range of pH. The pH of the water and precipitation of the secondary metal-(oxy)hydroxides in the bottom sediment are found to be the controlling factors for the occurrence and growth of algal biomass. The concentration of Cu, Fe, Ni, Pb, and Zn in mine discharges has been reduced by many folds in downstream of the algal site. The algal biomass contains very high concentration of metals, particularly Fe and Cu; the order of the metal content is Fe > Cu > Zn > Ni > Pb. This study also demonstrates the influence of pH on distribution of metals in algae. The concentration of Fe and Cu ranges from 0.95 to 9.14% and 1.74 to 3.66%, respectively. Based on this study, it is found that Microspora can be used as bioindicator of acid mine drainage (AMD) impact around copper mine. Due to the exceptionally high metal accumulation potential, Microspora-dominated algal biomass can be used for bioremediation of the AMD and recovery of Cu in particular.

Applications of environmental DNA methods for charophyte biodiversity

The use of environmental DNA (eDNA) for qualitative species inventories offers great potential as a cost-effective tool for species identification. This requires that the target species release DNA, reference information is available and detection methods exist. Environmental DNA analyses are currently used routinely to inventory fish fauna (Wang et al. 2021), molluscs (Klymus et al. 2017) or insects (Uchida et al. 2020). For other groups, such as macrophytes, there is not much information available (Scriver et al. 2015). In plants, identifying suitable eDNA markers been much more challenging, as no single DNA region has been accepted for the purposes of barcoding. Within this project, we assessed if stoneworts (Charophytes, Characeae) can be detected by using eDNA analysis and if it can be used to support macrophyte monitoring. Charophytes are macroscopic green algae which, because of their role as habitat engineers, are of special importance for aquatic ecosystems. Many charophyte species are bound to clean, nutrient-poor fresh and brackish waters (e.g. Melzer 1999) and are regarded bioindicators for water quality by national and international directives (e.g. Habitats Directive, EU Water Framework Directive). Being sensitive to anthropogenic pressures, a drastic decline in populations with increasing eutrophication has been reported (Sand-Jensen et al. 2017) . However, the diversity of Characeae is often underestimated due to difficulties in morphological determination, and the genetic identification of charophytes has been established only in the recent few years (e.g. Nowak et al. 2016). We assessed the potential utility of eDNA to document the diversity of charophyte species. eDNA from a fresh water lake (Dreetzsee, Germany, 2018) and from a brackish water site (Darß-Zingst Lagoon System, Germany, 2018) was extracted from filtered or ethanol‐precipitated water samples, and we designed and tested eDNA markers based on four regions of the chloroplast genome - atpB, rbcL, psbC, and matK. Of the four regions, matK and rbcL were most likely to amplify DNA from charophyte species. Both sites exhibit a diverse charophyte flora, which we successfully could identify to species/group level by eDNA analysis. In a current study, the developed eDNA markers are used to scrutinize the charophyte population of the Schlei estuary (Germany, Schleswig-Holstein). Since conventional monitoring can only be carried out once a year at a few sites, Characeae have not been observed in recent years, or only very sporadically. As it is not possible to survey the entire Schlei, especially due to high water turbidity, the eDNA methodology is tested to assess the presence of Characeae species.

Entomotoxic Activity of Prasiola crispa (Antarctic Algae) in Nauphoeta cinerea Cockroaches: Identification of Main Steroidal Compounds.

Prasiola crispa is a macroscopic green algae found in abundance in Antarctica ice free areas. Prasiola crispan-hexaneextract (HPC) induced insecticidal activity in Nauphoeta cinerea cockroaches after 24 h of exposure. The chemical analysis of HPC revealed the presence of the followingphytosterols: β-sitosterol, campesterol and stigmasterol. The incubation of cockroach semi-isolated heart preparations with HPC caused a significant negative chronotropic activity in the heartbeats. HPC affected the insect neuromuscular function by inducing a complete inhibition of the cockroach leg-muscle twitch tension. When the isolated phytosterols were injected at in vivo cockroach neuromuscular preparations, there was a progressive inhibition of muscle twitches on the following order of potency: β-sitosterol > campesterol > stigmasterol. HPC also provoked significant behavioral alterations, characterized by the increase or decrease of cockroach grooming activity, depending on the dose assayed. Altogether, the results presented here corroborate the insecticide potential of Prasiola crispa Antarctic algae. They also revealed the presence of phytosterols and the involvement of these steroidal compounds in the entomotoxic activity of the algae, potentially by modulating octopaminergic-cholinergic pathways. Further phytochemical-combined bioguided analysis of the HPC will unveil novel bioactive compounds that might be an accessory to the insecticide activity of the algae.

Diversity and Distribution of Characeae in the Maghreb (Algeria, Morocco, Tunisia)

Characeae are macroscopic green algae present in the Maghreb (Morocco, Algeria, Tunisia) that are known since the 19th century works of Desfontaines (1800) and Braun (1868). Feldmann (1946) published the first regional synthesis, and this study provides a new Maghreb-wide synthesis of all collections made since 1784 (570 observations distributed over 464 sites). Each of the 31 reported species is described in detail with its diagnostic features, ecology and distribution in the three Maghrebian countries. Distribution maps distinguish between the three collection periods: 1780–1939, 1940–1979, and 1980–2016. An illustrated key is provided to help botanists working in the Maghreb to identify the taxa. From a biogeographical perspective, the Characean flora of the Maghreb is dominated by elements originating from northern (European) countries (61.3%) that include regionally very rare species such as Chara strigosa and C. tomentosa. The Mediterranean-Atlantic element is also well represented (32.3%), with some Mediterranean endemics (Chara imperfecta, C. oedophylla, C. vulgaris var. gymnophylla). Finally, two taxa that have an affinity for tropical conditions (Chara zeylanica and Lamprothamnium succinctum) extend to the southern Sahara. In North Africa, 14 species (7 Chara, 2 Lamprothamnium, 4 Nitella and 1 Sphaerochara) are threatened and raise issues about their conservation; three of these are particularly endangered: Chara imperfecta, C. oedophylla and Lamprothamnium papulosum.

Canopy cover as the key factor for occurrence and species richness of subtropical stream green algae (Chlorophyta)

Understanding how local and regional environmental factors influence species richness remains a key issue in ecology. Green algae (Chlorophyta) are a diverse and widely occurring group, which may be a good model for studying the factors that influence species richness at local and regional scales. Here, we tested the influence of local (water quality and structural complexity) and regional environmental factors (phyto-ecological regions) on the occurrence and species richness of macroscopic green algae (MGA) in subtropical streams. We sampled algae in 105 streams located in the four major phyto-ecological regions of the Brazilian subtropics. We used cross-transect technique in streams to sample algae and environmental variables. To determine the most important variables in species occurrence and richness, we used Hierarchical Partitioning analysis (HP). We found that canopy cover alone explained 34% of MGA occurrence, regardless of phyto-ecological region. At the sites where MGA occurred, the species richness was determined by both regional and local factors. The species richness was mainly influenced by phyto-ecological region, which explained 34% of the variation in species richness, along with canopy cover and pH which explaining 22% and 15% respectively. The highest richness was found in non-forested regions, in transects without canopy cover, and slightly acidic pH. Our results illustrate how the combination of regional and local factors can shape the spatial distribution of species richness and are pivotal to understanding richness patterns at broad spatial scales.

Carbon Dynamics in a Hardwater Lake: Effect of Charophyte Biomass on Carbonate Deposition

ABSTRACT: The photosynthetic activity of phytoplankton (in pelagial) and macrophytes (in littoral) is considered to be one of the main factors affecting the carbon cycle in lakes. This concerns in particular hardwater ecosystems, where most of the carbon is available in the form of Ca- or Mg-bicarbonates. In such ecosystems charophytes (macroscopic green algae, forming dense meadows) are regarded as the most effective carbonate producer due to the HCO3 — utilization and the formation of thick CaCO3 encrustations. Calcium carbonate and biomass production of charophytes were studied in a small and shallow charophyte-dominated Lake Jasne (Western Poland). Fresh and dry weight of plants, percentage contribution of calcium carbonate and production of CaCO3 per 1 m2 were studied at three depths (1, 3 and 5 m) in three sample sites (each sampled area — 0.04 m2). Additionally, physical-chemical parameters of water samples were studied. It was found that the dry weight of charophytes and the values of calcium carb...

The significance of Chara vegetation in the precipitation of lacustrine calcium carbonate

AbstractA significant portion of calcium carbonate is deposited in lake sediments as a result of biological processes related to the photosynthetic activity of phytoplankton in the pelagic realm and, in addition, macrophytes in the littoral zone. Lake Wigry, one of the largest lakes in Poland (north‐east Poland), is characterized by: (i) carbonate sediments with a CaCO3 content exceeding 80% within the littoral zone; and (ii) large areas of submerged vegetation dominated by charophytes (macroscopic green algae, Characeae family). It is claimed that charophytes are highly effective in utilizing HCO3− and forming thick CaCO3 encrustations. Thus, this study was aimed at evaluating the CaCO3 production by dense Chara stands overgrowing the lake bottom reaching a depth of 4 m. In late July 2009, the fresh and dry mass of plants, the percentage contribution of calcium carbonate and the production of CaCO3 per 1 m2 were investigated along three transects at three depths (1 m, 2 m and 3 m, with each sample area equal to 0·0625 m2) per transect. The composition and structure of phytoplankton and the physico‐chemical properties of the water analysed in both the littoral and pelagic zones served as the environmental background and demonstrated moderately low fertility in the lake. The greatest dry plant mass exceeded 1000 g m−2 and CaCO3 encrustations constituted from 59% to over 76% of the charophyte dry weight. Thus, the maximum and average values of carbonates precipitated by charophytes were 685·5 and 438 g m−2, respectively, which exceeded previously reported results. A correlation of carbonate production with the depth of Chara stands was detected, and intermediate depths offered the most favourable conditions for carbonate precipitation (589 g m−2 on average). As precipitated carbonates are ultimately stored in bottom deposits, the results highlight the significance of charophytes in lacustrine CaCO3 sedimentation.

Benthic diatoms of the Vistula River estuary (Northern Poland): Seasonality, substrata preferences, and the influence of water chemistry

SUMMARYSeasonal studies of water bodies in separate branches of the Vistula River estuary in Northern Poland were conducted over 30 months from May 2005 to October 2007. Diatom samples were collected from different substrata from two sites located in the river mouth, which has physical characteristics as a result of a complex interplay of natural and human influences that have taken place over the last 100+ years. The diatom flora growing on hard surfaces near the river banks such as sand, muddy sand, rocks, macroscopic green algae and/or vascular aquatic plants was recorded. All diatom taxa collected were distinguished based on their morphological features using light (LM) and scanning electron microscopy (SEM). A total of 187 species belonging to 61 genera were identified. A canonical correspondence analysis indicated that the diatom assemblages were definitely associated with salinity as well as nutrient concentrations and substratum type. During the study, malformations of diatom valves were observed in 48% of the microphytobenthos samples. Abnormal outline morphology and ornamentation deformities in several individuals of nine different species were recorded, which were mainly in epilithic and epiphytic communities collected from spring to autumn.

Transient existence of life without a cell membrane: a novel strategy of siphonous seaweed for survival and propagation.

Siphonous seaweeds, which constitute a vital component of coral reefs, are structurally simple, single-celled coenocytic macroscopic green algae. Kim et al.1 have recently shown the extraordinary wound-repair and propagation mechanism of one such siphonous green alga--Bryopsis plumosa. Nucleocytoplasmic aggregates, which are released after injury to this plant, are membraneless structures that can survive in seawater for 10-20 minutes, before they are surrounded by a gelatinous envelope. Subsequently, a cell membrane and cell wall are synthesized around each of these aggregates and the resulting individual cells, so formed, develop into new plants. This report represents a significant advance in our understanding of wound response and, more significantly, is probably the first example of transient survival of life without a cell membrane!

The Myxophyceae of the Marshes of Southern Delaware

Thirty-six species of blue-green algae were observed in collections from the marshes of southern Delaware. All major vegetational zones support a single myxophycean association dominated by the three primary oscillatoriaceous species (sensu Drouet, 1968)Microcoleus lyngbyaceus (Kutzing) Crouan,Schizothrix calcicola (Agardh) Gomont andSchizothrix arenaria (Berkeley) Gomont. All three species contribute to the formation of coherent mats over the marsh sediments in bare areas subject to alternate periods of inundation by salt water and exposure. Firm mats are not produced unlessS. arenaria is present in abundance. Pannes and pools support the largest populations of blue-green algae in the summer. Significant but reduced populations overwinter in mats of macroscopic green algae and among the dead, lodged culms of the grasses of the high and low marshes. The availability of light at the sediment surface and the extent to which it is attenuated by the marsh angiosperms are the major factors determining the distribution of the algae on the marshes. When synonymy is taken into account, there is considerable agreement among the various published accounts of the myxophycean floras of marshes in the temperate North Atlantic region. It is suggested that the myxophycean association found on the marshes of southern Delaware may, with certain reservations, be taken as the type of a single ubiquitous, endemic temperate North Atlantic blue-green algal association. *** DIRECT SUPPORT *** A00BY066 00005

Inhibition of photosynthetic electron transport by DDT and DDE.

The effect of DDT and DDE (a metabolite of DDT) on chloroplast electron transport was investigated. Photosynthetic electron transport in isolated spinach and barley chloroplasts as well as chloroplasts isolated from macroscopic green algae,Cdium fragile andChaetomorpha aerea, was inhibited by both compounds. Photoreduction and photophosphorylation measured in the presence of ferricyanide showed 50% inhibition at 2×10−5 M DDT and DDE. P/2e ratios were 1·2–1·5, and remained constant in the presence of both inhibitors. The addition of uncouplers such as ammonium ion and carbonyl cyanide,m-chlorophenylhydrazone did not overcome the inhibition of the chlorinated hydrocarbons. Inhibition of phenazine methosulfate-catalyzed cyclic photophosphorylation by DDT and DDE was observed at low light intensities but was not seen at 2·5×105 erg cm−2sec−1 and above. In the presence of DDT, a slow rise in measuring beam fluorescence was observed. The actinic beam fluorescence was slightly less than that in the control. Inhibition by DDT and DDE appears to be similar to that of DCMU. Brief sonication of the chloroplasts increases the sensitivity to DDT. The lack of penetration of DDT to terrestrial plant chloroplasts may be the reason why these are protected from this insecticide.

The Trapping and Binding of Subtidal Carbonate Sediments by Marine Vegetation in Bimini Lagoon, Bahamas

ABSTRACT In the shallow water lagoon of Bimini, Bahamas, the following plants are sufficiently abundant to influence sedimentation locally.--mangroves (Rhizophora mangle), marine grass (Thalassia testudinum), macroscopic green algae (Penicillus, Batophora, Halimeda, Rhipocephalus and Udotea) and microscopic red, green and blue-green algae forming surface mats of intertwining filaments (Laurencia, Enteromorpha, Lyngbya and (?)Schizothrix). Plants were observed under conditions of natural tidal currents and artificial unidirectional currents produced in an underwater flume and measurements were made of the abilities of the plants to trap and bind the carbonate sediment. The density of plant growth is crucial in the redu tion of current strength at the sediment-water interface. The most effective baffles are Rhizophora roots exposed above the sediment, dense Thalassia blades and Thalassia blades with dense epiphytic algae, Laurencia intricata and Polysiphonia havanensis. All three types can reduce the velocity of water from a speed sufficiently high to transport loose sand grains along the bottom in clear areas (30 cm/sec) to zero at the sediment-water interface in the vegetated areas. The strongest binders of sediment are the roots of Rhizophora and Thalassia. These two hardy plants trap and bind sediment for a sufficient time to produce an accumulation higher than in nearby areas without dense mangroves or grass. Macroscopic green algae growth is not suf iciently dense and the holdfasts too weak to appreciably affect the accumulation of sediment although they provide a degree of stabilization to the substrate. Algal mats trap sediment chiefly by adhesion of grains to the sticky filaments. Their ability to resist erosion by unidirectional currents varies considerably depending on mat type, smoothness of surface and continuity of the cover. The intact areas of dense Enteromorpha mat can withstand currents five times stronger than those that erode loose unbound sand grains. Premature erosion of mats by currents occurs at breaks in the mat surface caused by the burrowing or browsing action of animals. Algal mats were found to be ephemeral features and consequently do not build up thick accumulations of sediment as do dense grass and m ngroves. The thickest accumulations of sediment in the lagoon correlate with deepest bedrock surfaces. The distribution of many plants in the lagoon is directly or indirectly controlled by the depth to bedrock; for example, mangroves on bedrock highs, marine grass in sediment-filled depressions.