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.

A First Estimate of Species Diversity for Benthic Diatom Assemblages from the Revillagigedo Archipelago, Mexico

Recent investigations at previously unexplored localities on the Mexican coast have confirmed the high taxonomic potential of benthic marine diatom assemblages (BMDA) in the region. An exploratory study of epiphytic diatoms of macroalgae in the Revillagigedo Archipelago (RA) suggested that further studies would yield many more taxa, prompting the hypothesis that diversity measurements, based on ecological indices, would be among the highest in pristine environments. Thus, the aim of this research was to enrich the record of epiphytic diatom floristics of the RA, and to estimate species diversity based on information theory (H′). Floristically, 167 identified taxa are added here to the BMDA species list of the RA, bringing the total to 397 taxa overall, including 52 taxa that are potentially new records for the Mexican Pacific coast. Among the most conspicuous genera are Mastogloia with five new taxa and it remains the most diverse genus with 55 taxa overall, followed by Cocconeis (27), Nitzschia (24), Amphora (23), Navicula (19), Diploneis (17) and Grammatophora (15). As expected for a pristine environment, the computed species diversity values for the BMDA were high, ranging from H′ = 3.92–5.2, depicting stability. Future surveys are expected to further increase the species richness of BMDA for the RA.

Epiphytic diatoms on herbarium material from the Central Forest phytogeographic region of the Democratic Republic of the Congo

Background and aims – Epiphytic diatoms are excellent bio-indicators of the present and past ecological condition of aquatic ecosystems. In order to reconstruct the diatom history and to evaluate its diversity in the Democratic Republic of the Congo, epiphytic diatoms were sampled from herbarium specimens of aquatic plants deposited at the National Herbarium of the Congo at Yangambi (YBI) and at the herbarium of Meise Botanic Garden (BR).Material and methods – In YBI, nine specimens belonging to the Nymphaeaceae, three to the Ceratophyllaceae, and 12 to the Lentibulariaceae collected in the Central Forest phytogeographic region were sampled for diatom investigation. In addition, nine Nymphaea lotus specimens were sampled in BR. Semi-quantitative analyses were performed by light microscopy on permanent diatom slides.Key results – Analyses of the epiphytic diatom communities on YBI and BR materials showed a large diversity of 132 species belonging to 44 genera. Taxa belonging to the genus Eunotia were relatively the most abundant in all studied samples followed by Frustulia saxonica and a Desmogonium sp. The diatom communities on Nymphaea were as varied as on Ceratophyllum, while on Utricularia, a significant lower diversity was observed. The Trophic Diatom Index (TDI) and Generic Diatom Index (GDI) showed that the water quality in the Central Forest phytogeographic region was overall good during the 20th century. They point to oligotrophic conditions for the running waters with a slight increase towards more mesotrophic conditions from the 1950s onwards. The only sample in the present study indicating mesotrophic condition was from a swamp.Conclusions – The results on the epiphytic diatoms present on herbarium material can serve as a basis for sustainable management of aquatic ecosystems in D.R. Congo. In absence of an in-depth knowledge of the species and their ecological preferences, a genus-based TDI and IDG have proven to be valuable tools for water quality monitoring in tropical Africa.

TOTAL OIL CONTENT AND EPIPHYTIC DIATOM DENSITY IN SEAGRASSES LEAVES Enhalus acoroides AT PANDARATAN BEACH TAPANULI TENGAH REGENCY NORTH SUMATERA PROVINCE

The aimed of this study was to determine the total oil content at Pandaratan Beach, determine epiphytic diatoms density in seagrass leaves Enhalus acoroides at Pandaratan Beach, and determined the relationship between total oil content and epiphytic diatoms density in seagrass leaves E. acoroides at Pandaratan Beach. Based on the results of research conducted, the highest total oil content is in the area around the sea transportation route, namely 0.25 ppm and the lowest total oil content is in areas far from human activity, namely 0.16 ppm. The highest epiphytic diatoms density found in areas far from human activities, namely 932.21 Ind/cm2 and the lowest epiphytic diatoms density found in the area around the sea transportation lines, namely 663.41 Ind/cm2.The relationship between total oil content and epiphytic diatoms density at Pandaratan Beach, Tapanuli Tengah Regency, North Sumatra Province has a very weak relationship (r = 0.03).

Diatom communities differ among Antarctic moss and lichen vegetation types

Continental Antarctica is a polar desert containing sparse pockets of vegetation within ice-free areas. Despite the recognized association between lichens, mosses and epiphytic diatoms, the environmental factors controlling diatom community structure are poorly understood. We investigated the association between diatom communities and host vegetation characteristics by experimentally adding nutrients and/or water to two bryophyte (healthy and moribund) and two lichen (crustose and Usnea) vegetation types in the Windmill Islands. Diatom communities were morphologically characterized, diversity indices calculated and differences between treatments, vegetation type and vegetation characteristics tested. We identified 49 diatom taxa, 8 of which occurred with > 1% relative abundance. Bryophyte and lichen vegetation harboured significantly different diatom communities, both in composition and diversity indices. Specifically, Luticola muticopsis was more prevalent in moribund bryophytes and crustose lichens, and Usnea lichens showed lower species richness than other types. While nutrient and water additions did not significantly alter diatom communities, diversity indices and some species showed relationships with vegetation physiological characteristics, notably %N and δ13C, suggesting the importance of ambient gradients in water and nutrient availability. Collectively, this work suggests that future conditions favouring the dominance of a particular vegetation type may have a homogenizing effect on the terrestrial diatom communities of East Antarctica.

Morphology and occurrence of two epibiotic marine gomphonemoid diatoms in China

Gomphonemoid diatoms exist in both freshwater and marine environment, but marine gomphonemoid taxa are morphologically different from Gomphonema. Although the marine gomphonemoid group has been expanded with many new taxa in recent years, only the genus Gomphonemopsis was described from Chinese seas. The present study reports on species diversity and classification of marine epiphytic diatoms on seaweeds and epizoic diatoms on animals collected from several stations in the South Yellow Sea and East China Sea. Two marine gomphonemoid diatoms, Pseudogomphonema kamtschaticum and Gomphoseptatum aestuarii, were observed and identified by light and electron microscopy, representing the first record in China of these two species and genera. Our observations matched the basic features of original species descriptions. Except that we observed in P. kamtschaticum showed various areolae shapes (e. g., slit-like, "I"-like, "C"-like and circular), and ornamented macroareolae with small warts were observed in G. aestuarii. Both P. kamtschaticum and G. aestuarii were epiphytic on the seaweed Sargassum hor neri, and P. kamtschaticum was found as epizoic on an ophiuroid species of the Ophiura genus. Therefore, we have increased the records of and knowledge about marine gomphonemoid diatoms to three genera with four species in China, including Gomphonemopsis.