Changing depositional environments in the semi-restricted Late Jurassic Lemeš Basin (Outer Dinarides; Croatia)

The up to 450 m-thick Upper Jurassic Lemeš Formation includes organic-rich deep-water (max. ~ 300 m) sedimentary rocks deposited in the Lemeš Basin within the Adriatic Carbonate Platform (AdCP). The Lemeš Formation was investigated regarding (1) bio- and chemostratigraphy, (2) depositional environment, and (3) source rock potential. A multi-proxy approach—microfacies, Rock–Eval pyrolysis, maceral analysis, biomarkers, and stable isotope ratios—was used. Based on the results, the Lemeš Formation is subdivided from base to top into Lemeš Units 1–3. Deposition of deep-water sediments was related to a late Oxfordian deepening event causing open-marine conditions and accumulation of radiolarian-rich wackestones (Unit 1). Unit 2, which is about 50 m thick and Lower early Kimmeridgian (E. bimammatum to S. platynota, ammonite zones) in age, was deposited in a restricted, strongly oxygen-depleted basin. It consists of radiolarian pack- and grainstones with high amounts of kerogen type II-S organic matter (avg. TOC 3.57 wt.%). Although the biomass is predominantly marine algal and bacterial in origin, minor terrestrial organic matter that was transported from nearby land areas is also present. The overlying Unit 3 records a shallowing of the basin and a return to oxygenated conditions. The evolution of the Lemeš Basin is explained by buckling of the AdCP due to ophiolite obduction and compressional tectonics in the Inner Dinarides. Lemeš Unit 2 contains prolific oil-prone source rocks. Though thermally immature at the study location, these rocks could generate about 1.3 t of hydrocarbon per m2 surface area when mature.

Cobalt: An Essential Micronutrient for Plant Growth?

Cobalt is a transition metal located in the fourth row of the periodic table and is a neighbor of iron and nickel. It has been considered an essential element for prokaryotes, human beings, and other mammals, but its essentiality for plants remains obscure. In this article, we proposed that cobalt (Co) is a potentially essential micronutrient of plants. Co is essential for the growth of many lower plants, such as marine algal species including diatoms, chrysophytes, and dinoflagellates, as well as for higher plants in the family Fabaceae or Leguminosae. The essentiality to leguminous plants is attributed to its role in nitrogen (N) fixation by symbiotic microbes, primarily rhizobia. Co is an integral component of cobalamin or vitamin B12, which is required by several enzymes involved in N2 fixation. In addition to symbiosis, a group of N2 fixing bacteria known as diazotrophs is able to situate in plant tissue as endophytes or closely associated with roots of plants including economically important crops, such as barley, corn, rice, sugarcane, and wheat. Their action in N2 fixation provides crops with the macronutrient of N. Co is a component of several enzymes and proteins, participating in plant metabolism. Plants may exhibit Co deficiency if there is a severe limitation in Co supply. Conversely, Co is toxic to plants at higher concentrations. High levels of Co result in pale-colored leaves, discolored veins, and the loss of leaves and can also cause iron deficiency in plants. It is anticipated that with the advance of omics, Co as a constitute of enzymes and proteins and its specific role in plant metabolism will be exclusively revealed. The confirmation of Co as an essential micronutrient will enrich our understanding of plant mineral nutrition and improve our practice in crop production.

New marine algal records from Arabian Gulf coastline of Kuwait

During 2014-2016 a project was launched to update and examine the current status of five phyla of benthic marine algae, in addition to epiphytic diatoms and marine Tracheophyta thriving along the coastal area of Kuwait. 173 species of algae were collected and identified. Fourteen new records of algal species for Kuwait including 2 species as new records from the Arabian Gulf are here reported for the first time. These species are assigned to the Chlorophyta (4), Ochrophyta (1), Rhodophyta (5) and Cyanobacteria (4). From Kuwait coastal line one species of marine angiosperm is also found for the first time. Five algal species collected from Kuwait coastal line remain unidentified.

Ecological Studies on Marine Algal-Dwelling Copepoda (Harpacticoida) from Wellington, New Zealand

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>

Ecological Studies on Marine Algal-Dwelling Copepoda (Harpacticoida) from Wellington, New Zealand

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>

A novel random forest approach to revealing interactions and controls on chlorophyll concentration and bacterial communities during coastal phytoplankton blooms

Increasing occurrence of harmful algal blooms across the land–water interface poses significant risks to coastal ecosystem structure and human health. Defining significant drivers and their interactive impacts on blooms allows for more effective analysis and identification of specific conditions supporting phytoplankton growth. A novel iterative Random Forests (iRF) machine-learning model was developed and applied to two example cases along the California coast to identify key stable interactions: (1) phytoplankton abundance in response to various drivers due to coastal conditions and land-sea nutrient fluxes, (2) microbial community structure during algal blooms. In Example 1, watershed derived nutrients were identified as the least significant interacting variable associated with Monterey Bay phytoplankton abundance. In Example 2, through iRF analysis of field-based 16S OTU bacterial community and algae datasets, we independently found stable interactions of prokaryote abundance patterns associated with phytoplankton abundance that have been previously identified in laboratory-based studies. Our study represents the first iRF application to marine algal blooms that helps to identify ocean, microbial, and terrestrial conditions that are considered dominant causal factors on bloom dynamics.

Potential Antiviral Properties of Industrially Important Marine Algal Polysaccharides and Their Significance in Fighting a Future Viral Pandemic

Over the decades, the world has witnessed diverse virus associated pandemics. The significant inhibitory effects of marine sulfated polysaccharides against SARS-CoV-2 shows its therapeutic potential in future biomedical applications and drug development. Algal polysaccharides exhibited significant role in antimicrobial, antitumor, antioxidative, antiviral, anticoagulant, antihepatotoxic and immunomodulating activities. Owing to their health benefits, the sulfated polysaccharides from marine algae are a great deal of interest globally. Algal polysaccharides such as agar, alginate, carrageenans, porphyran, fucoidan, laminaran and ulvans are investigated for their nutraceutical potential at different stages of infection processes, structural diversity, complexity and mechanism of action. In this review, we focus on the recent antiviral studies of the marine algae-based polysaccharides and their potential towards antiviral medicines.