Book

Intercalibration and Distribution of Diatom Species in the Baltic Sea 5

January 1998

Publisher: Opulus Press Uppsala

Authors:

Pauline J. M. Snoeijs

Stockholm University

Nataliya Balashova

St Petersburg University

Volume 5 in a series which has resulted from a joint intercalibration programme of the Baltic Marine Biologists (BMB) Working Group 27. Each species is illustrated with a photograph and extensive references to the appropriate up-to-date information literature. This book can be ordered from http://www.nhbs.com and other internet book stores. In volumes 1-5 the following 500 species are treated, all, illustrated, each on a separate page: Achnanthes amoena Achnanthes bahusiensis Achnanthes bremeyeri Achnanthes brevipes Achnanthes brevipes var. intermedia Achnanthes cf. minuscula Achnanthes dispar Achnanthes fimbriata Achnanthes fogedii Achnanthes groenlandica Achnanthes lemmermannii Achnanthes linkei Achnanthes longipes Achnanthes oblongella Achnanthes pericava Achnanthes submarina Achnanthes vistulana Achnanthidium microcephalum Achnanthidium minutissimum Achnanthidium thermale Actinocyclus normanii Actinocyclus normanii fo. subsalsus Actinocyclus octonarius var. crassus Actinocyclus octonarius var. tenellus Actinoptychus senarius Amphora abludens Amphora acutiuscula Amphora beaufortiana Amphora cf. bacillaris Amphora cf. exigua Amphora cf. tenerrima Amphora coffeaeformis Amphora commutata Amphora copulata Amphora decussata Amphora fogediana Amphora helenensis Amphora holsatica Amphora hyalina Amphora hybrida Amphora laevissima Amphora lineolata Amphora luciae Amphora macilenta var. typica Amphora maletractata var. constricta Amphora micrometra Amphora ostrearia var. lineata Amphora ovalis Amphora pediculus Amphora rhombica var. intermedia Amphora robusta Amphora staurophora Amphora subholsatica Amphora veneta Amphora wisei Anaulus balticus Aneumastus minor Aneumastus tusculus Anomoeoneis sphaerophora fo. costata Anomoeoneis sphaerophora fo. sculpta Anorthoneis vortex Ardissonea crystallina Ardissonea fulgens Asterionella formosa Attheya decora Attheya septentrionalis Aulacoseira islandica Aulacoseira subarctica Bacillaria paxillifer Berkeleya fennica Berkeleya micans Berkeleya rutilans Biremis ambigua Biremis lucens Brachysira aponina Kützing Brachysira vitrea Brebissonia lanceolata Caloneis aemula Caloneis amphisbaena Caloneis amphisbaena fo. subsalina Caloneis bacillum Caloneis crassa Campylodiscus bicostatus Campylodiscus clypeus Campylodiscus echeneis Catenula adhaerens Cavinula cocconeiformis Cavinula pseudoscutiformis Cerataulina pelagica Cerataulus turgidus Chaetoceros affinis Chaetoceros brevis Chaetoceros cf. borealis Chaetoceros cf. fallax Chaetoceros danicus Chaetoceros decipiens Chaetoceros diadema Chaetoceros holsaticus Chaetoceros mitra Chaetoceros muelleri var. subsalsum Chaetoceros similis Chaetoceros simplex Chaetoceros subtilis Chaetoceros throndsenii Chaetoceros wighamii Cocconeis costata Cocconeis disculus Cocconeis molesta var. crucifera Cocconeis neothumensis Cocconeis pediculus Cocconeis peltoides Cocconeis placentula Cocconeis placentula var. euglypta Cocconeis pseudomarginata Cocconeis quarnerensis Cocconeis scutellum Cocconeis speciosa Cocconeis stauroneiformis Coscinodiscus asteromphalus Coscinodiscus granii Coscinodiscus radiatus Coscinodiscus wailesii Cosmioneis pusilla Craticula cuspidata Ctenophora pulchella Cyclostephanos dubius Cyclotella atomus Cyclotella choctawhatcheeana Cyclotella meneghiniana Cyclotella radiosa Cyclotella schumannii Cyclotella stelligera Cylindrotheca closterium Cymatopleura elliptica Cymatopleura solea Cymbella affinis Cymbella cistula Cymbella helvetica Cymbella lanceolata Cymbella pusilla Denticula creticola Denticula sundayensis Denticula tenuis var. crassula Diatoma bottnica Diatoma moniliformis Diatoma tenuis Diatoma vulgaris Dickieia subinflata Didymosphenia geminata Dimeregramma minor Diploneis decipiens var. parallela Diploneis didyma Diploneis domblittensis Diploneis interrupta Diploneis litoralis Diploneis mauleri Diploneis oculata Diploneis smithii Diploneis smithii var. dilatata Diploneis smithii var. pumila Diploneis smithii var. rhombica Diploneis stroemii Diploneis suborbicularis Ditylum brightwellii Donkinia angusta Donkinia recta var. minuta Ellerbeckia arenaria Encyonema caespitosum Encyonema lacustre Encyonema prostratum Encyonema silesiacum Encyonopsis behrei Encyonopsis microcephala Entomoneis paludosa Entomoneis pseudoduplex Entomoneis punctulata Epithemia adnata Epithemia sorex Epithemia turgida Epithemia turgida var. westermannii Eucampia zodiacus Fallacia clepsidroides Fallacia cryptolyra Fallacia florinae Fallacia forcipata Fallacia litoricola Fallacia plathii Fallacia pseudolitoricola Fallacia pseudony Fallacia pygmaea Fallacia tenera Fragilaria amicorum Fragilaria capucina Fragilaria crotonensis Fragilaria gedanensis Fragilaria heidenii Fragilaria hyalina var. durietzii Fragilaria inflata var. istvanffyi Fragilaria parasitica Fragilaria striatula Fragilaria vaucheriae Fragilariopsis cylindrus Frustulia creuzburgensis Gomphocymbella ancyli Gomphonema acuminatum var. coronatum Gomphonema olivaceum Gomphonema parvulum Gomphonemopsis exigua Gomphonemopsis exigua var. platypus Gomphonemopsis pseudexigua Grammatophora marina Grammatophora oceanica Guinardia flaccida Gyrosigma acuminatum Gyrosigma attenuatum Gyrosigma balticum Gyrosigma eximium Gyrosigma fasciola Gyrosigma macrum Gyrosigma strigilis Hantzschia virgata Hantzschia virgata var. gracilis Hantzschia virgata var. wittii Haslea crucigera Haslea crucigeroides Haslea ostrearia Hustedtiella baltica Hyalodiscus scoticus Hyalosira delicatula Karayevia clevei Leptocylindrus danicus Leptocylindrus minimus Licmophora abbreviata Licmophora communis Licmophora dalmatica Licmophora debilis Licmophora gracilis var. anglica Licmophora hyalina Licmophora oedipus Licmophora rhombica Lunella bisecta Luticola mutica Lyrella sulcifera Martyana atomus Martyana martyi Martyana schulzii Mastogloia baltica Mastogloia braunii Mastogloia elliptica Mastogloia exigua Mastogloia lanceolata Mastogloia pumila Mastogloia pusilla Mastogloia smithii Mastogloia smithii var. amphicephala Melosira arctica Melosira lineata Melosira moniliformis Melosira nummuloides Melosira varians Melosira westii fo. parva Meridion circulare Navicula aboensis Navicula arenaria Navicula armoricana Navicula bipustulata Navicula bottnica Navicula capitata var. hungarica Navicula clamans Navicula crucicula Navicula cruciculoides Navicula cryptocephala Navicula decussis Navicula digitoradiata Navicula directa Navicula duerrenbergiana Navicula eidrigiana Navicula finmarchica Navicula flanatica Navicula germainii Navicula germanopolonica Navicula gregaria Navicula infirmitata Navicula integra Navicula jentzschii Navicula lanceolata Navicula laterostrata Navicula lesmonensis Navicula margaritiana Navicula meniscus Navicula microdigitoradiata Navicula oblonga Navicula oestrupii Navicula palpebralis Navicula pavillardii Navicula pelagica Navicula peregrina Navicula perminuta Navicula phyllepta Navicula platystoma Navicula portanova Navicula protracta Navicula pseudocrassirostris Navicula radiosa Navicula ramosissima Navicula ramosissima var. torquata Navicula reinhardtii Navicula rhynchocephala Navicula salinarum Navicula scutelloides Navicula slesvicensis Navicula starmachioides Navicula supralitoralis Navicula tripunctata Navicula vanhoeffenii Navicula viminoides Neidium iridis var. amphigomphus Neosynedra provincialis Nitzschia acicularis Nitzschia ardua Nitzschia aurariae Nitzschia bacillum Nitzschia brevissima Nitzschia cf. angustatula Nitzschia cf. distans Nitzschia clausii Nitzschia dippelii Nitzschia dissipata Nitzschia dubia Nitzschia dubiiformis Nitzschia elegantula Nitzschia filiformis Nitzschia frigida Nitzschia frustulum Nitzschia grossestriata Nitzschia heufleriana Nitzschia inconspicua Nitzschia littorea Nitzschia lorenziana Nitzschia microcephala Nitzschia paleacea Nitzschia pusilla Nitzschia recta Nitzschia recta var. robusta Nitzschia reversa Nitzschia salinicola Nitzschia scalaris Nitzschia scalpelliformis Nitzschia sigma Nitzschia sigmoidea Nitzschia thermaloides Nitzschia valdestriata Nitzschia vitrea Odontella aurita Odontella mobiliensis Odontella sinensis Opephora marina Opephora olsenii Paralia sulcata Parlibellus berkeleyi Parlibellus delognei Parlibellus hamulifer Parlibellus plicatus Pauliella taeniata Petrodictyon gemma Petroneis granulata Petroneis humerosa Petroneis latissima Petroneis marina Petroneis monilifera Pinnularia acuminata Pinnularia appendiculata Pinnularia cruciformis Pinnularia elegans Pinnularia halophila Pinnularia lundii Pinnularia mesolepta Pinnularia neomajor Pinnularia quadratarea Placoneis clementis Placoneis gastrum Placoneis placentula Plagiogramma staurophorum Plagiotropis lepidoptera Plagiotropis tayrecta Plagiotropis vanheurckii Plagiotropis vitrea Planothidium calcar Planothidium delicatulum Planothidium dubium Planothidium frequentissimum Planothidium oestrupii Planothidium rostratum Planothidium septentrionalis Pleurosigma aestuarii Pleurosigma angulatum Pleurosigma elongatum Pleurosigma formosum Pleurosigma lanceolatum var. cuspidatum Pleurosigma salinarum Pleurosigma subsalsum Pleurosira laevis fo. polymorpha Porosira glacialis Proboscia alata Proschkinia poretzkajae Psammodictyon panduriforme var. continua Psammothidium bioretii Psammothidium punctulatum Psammothidium rossii Pseudogomphonema kamtschaticum Pseudonitzschia pseudodelicatissima Pseudonitzschia pungens Pseudosolenia calcar-avis Pseudostaurosira brevistriata Pseudostaurosira brevistriata var. inflata Pseudostaurosira perminuta Pseudostaurosira zeillerii Pteroncola inane Reimeria sinuata Rhabdonema arcuatum Rhabdonema minutum Rhizosolenia delicatula Rhizosolenia fragilissima Rhizosolenia hebetata fo. semispina Rhizosolenia pungens Rhizosolenia setigera Rhoicosigma compactum Rhoicosphenia curvata Rhopalodia acuminata Rhopalodia brebissonii Rhopalodia gibba Scoliotropis latestriata Sellaphora bacillum Sellaphora pupula Skeletonema costatum Skeletonema subsalsum Stauroneis acuta Stauroneis phoenicenteron Stauroneis simulans Stauroneis spicula Staurophora amphioxys Staurophora salina Staurophora wislouchii Staurosira cf. construens var. venter Staurosira construens Staurosira construens var. binodis Staurosira elliptica Stephanodiscus binderanus Stephanodiscus hantzschii Stephanodiscus hantzschii fo. tenuis Stephanodiscus minutulus Stephanodiscus neoastraea Stephanodiscus parvus Stephanodiscus rotula Striatella unipunctata Surirella brebissonii Surirella brightwellii var. baltica Surirella crumena Surirella minuta Surirella striatula Synedra acus Synedra ulna Tabellaria fenestrata Tabellaria flocculosa Tabularia fasciculata Tabularia investiens Tabularia ktenoeides Tabularia tabulata Tabularia waernii Terpsinoë americana Thalassionema nitzschioides Thalassiophysa hyalina Thalassiosira anguste-lineata Thalassiosira baltica Thalassiosira eccentrica Thalassiosira guillardii Thalassiosira hyperborea var. lacunosa Thalassiosira hyperborea var. pelagica Thalassiosira lacustris Thalassiosira levanderi Thalassiosira oestrupii Thalassiosira proschkinae Thalassiosira pseudonana Thalassiosira punctigera Thalassiosira weissflogii Trachyneis aspera Tryblionella apiculata Tryblionella circumsuta Tryblionella coarctata Tryblionella gracilis Tryblionella hungarica Tryblionella levidensis Tryblionella littoralis Tryblionella littoralis Tryblionella navicularis Tryblionella plana Tryblionella plana var. fennica Tryblionella punctata Tryblionella salinarum Undatella quadrata

Two new diatom species of the genus Gomphonemopsis (Bacillariophyceae) from the coast of China and two new combinations for the genus

Article

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Mar 2024

Two new diatom species belonging to the genus Gomphonemopsis are described, Gom-phonemopsis nana sp. nov. and Gomphonemopsis gaoi sp. nov. These two species were compared in detail with congeners. Gomphonemopsis nana is distinguished by its high stria density and small size. This species was found so far to be epiphytic only on the eelgrass collected from Qingdao Bay (Yellow Sea). Gomphonemopsis gaoi is characterized by its isopolar valves, simple proximal raphe endings and acutely rounded apices. This taxon was separated from the exoskeleton of marine copepods sampled from the Futian Mangrove Nature Reserve (South China Sea). In addition, two new combinations, Gomphonemopsis oahuensis (Hustedt), comb. nov. are proposed. This study increases the records and knowledge of Gomphonemop-sis along the coast of China.

New Records of Diatoms (Bacillariales, Rhopalodiales & Surirellales) with ultrastructure details from the Black Sea Coast of Turkey

Article

Full-text available

Nov 2021

Diatoms associated with the order Bacillariales, Rhopalodiales and Surirellales are well known to be present in marine and brackish waters. In this study, diatoms in the western Black Sea coasts of Turkey were investigated with ultrastructure details. Species belonging to the Bacillariales, Rhopalodiales and Surirellales were subject to light microscopy (LM) and scanning electron microscopy (SEM) analysis, and a total of twenty-four taxa were investigated. This study examines details on the morphology and biogeography of the taxa with remarks on their distribution in Turkey. The results revealed that four species were reported on the Turkish coasts for the first time. These species were Nitzschia liebethruthii, N. volvendirostrata, Epithemia guettingeri and Campylodiscus scalaris.

Epilithic diatoms (Bacillariophyceae) from cloud forest and alpine streams in Bolivia, South America

Article

Jan 2007

A floristic study based on epilithic samples collected from Bolivian cloud forest streams yielded a total of 172 taxa, 41 of which were new or could not be determined based on available literature. Five new taxa at the species and form levels (Gomphonema andinum, G. pumilum var. elegans f. biseriatum, G. pumilum var. rigidum f. biseriatum, Nitzschia boliviana, and N. soratensis) and two new combinations (Pseudostaurosira laucencis and Ulnaria contracta) are presented. Undetermined taxa are only listed herein and a more detailed study will be presented at a later date. The large number of taxa found in only a few samples suggests the Bolivian cloud forests may be a hot spot for epilithic diatom diversity. The use of combined light microscopy (LM) and scanning electron microscopy (SEM) data is of prime importance in the study of this diversity.

Epilithic diatoms (Bacillariophyta) from cloud forest and alpine streams in Bolivia, South America 3: Diatoms from Sehuencas, Carrasco National Parkc, Department of Cochabamba

Article

Full-text available

Oct 2009

Studies on Bolivian diatoms are scarce and they do not represent the great geographic variability of the country. One of the regions with the highest biological diversity in Bolivia is the Yungas (cloud forest), a 90.500 km2 strip located between the Andean Puna and the Amazonian lowlands. The Carrasco National Park is the park with the largest extension of Yungas within its boundaries. This park is located east from Cochabamba, the third largest city in Bolivia, and has an area of ca 6.226 km2, serving as a refuge to 5.000 recorded species of plants and more than 300 species of vertebrates. Very little is known about the aquatic biota in the zone and there are no studies on diatoms. One of the preferred tourist spots within the park is Sehuencas, located 17°31'42" S and 65°16'17" W and characterized by numerous lotic waterbodies. The present work was carried on 5 epilithic samples from which 118 species, varieties and forms were identified using light (LM) and scanning electron microscopy (SEM). Forty-two (36%) of these taxa were not found in the literature for South America or other regions of the world. This high percent age of unknown taxa suggests a high potential for the contribution of new organisms to science, many of which are possibly endemic to the region, thus justifying an additional effort to preserve the aquatic habitats in the park. Two new species are described herein (Fragilaria cochabambina Morales sp. nov. and Achnanthidium sehuencoensis Morales sp. nov.) and comparisons with published morphologically similar taxa are presented. Un knowns remain undescribed until larger populations that allow detailed LM and SEM studies are found.

Spatial variability of Holocene sediments in light studies of cores from the Arkona Basin, south-western Baltic Sea

Article

Jan 2025
QUATERN INT

Presented studies performed on two gravity cores with acoustic profiles, new radiocarbon dates from macro-fossils, and results from previous studies, have outlined the spatial variability of Arkona Basin sediments. Analyses of diatoms, grain size, and geochemistry revealed characteristics of the depositional environment developed during the Ancylus and Littorina stages. New geochemical data, along with previous results from western Arkona Basin using the PCA method, revealed division sediments across three groups, explained by terrigenous silica, organic matter, and calcium content factors. The grain size distribution together with geochemical parameters confirmed the existence of the erosional brackish-water basement, visible in the acoustic profiles as the distinct reflector R3. Reflector R3 is located at the boundary between Ancylus Lake and Littorina Sea sediments and stands base of the initial Littorina Sea. Comparing grain size characteristics of the sediments deposited during the Littorina Sea stage revealed spatial diversity of the depositional environment in the Arkona Basin. The western cores located close to Darss Sill during the onset of the Littorina stage confirmed a calm depositional environment, while in the northern part of the basin, dynamic activity of bottom currents was observed. During the second phase of the Littorina stage, dated around 6-5 ka cal. BP, there was an intensi-fication of sediment transport and deposition processes, accompanied by the appearance of marine diatom forms in the western cores. Simultaneously, relatively calm depositional conditions existed in the northern and central parts of the basin.

Holocene shoreline displacement, land-cover change and human settlement distribution on the southeast coast of Sweden

Article

Full-text available

Oct 2024
J QUATERNARY SCI

In this study, we investigate the interplay between relative sea-level changes, the development of human settlements and land-cover changes in the Västervik-Gamlebyviken region on the southeast coast of Sweden, an important archaeological area from the Mesolithic until recent times. The reconstruction of shore displacement was based on diatom analysis of radiocarbon-dated sediment cores from three lake basins combined with previously published lake isolation data. The resulting curve was used to construct palaeogeographical maps for selected time windows. Land-cover changes were inferred from pollen data from three lakes using the Landscape Reconstruction Algorithm with its two models REVEALS and LOVE. Our data suggest that people took advantage of the land gained due to an overall fall in relative sea level from~35 to~3 metres above sea level (m a.s.l.) over the last 10 000 years, interrupted by periods of transgression and highstands. A sea-level regression of~16 m occurred between 10 000 and 8500 cal a BP followed by an~3-4-m sea-level rise, reaching~22 m a.s.l. at~7500 cal a BP, which corresponds to the maximum Littorina Sea shoreline in the area. The available archaeological findings for the Mesolithic and Early Neolithic (8950-5450 cal a BP) agree well with the shore displacement curve showing that settlements and human activities were concentrated along or above the shorelines as defined from our study. During the transgression after 8500 cal a BP, however, seasonal settlements were submerged (as shown by findings of polished stone tools and hearths buried in sand) and used again during the subsequent regression after 4600 cal a BP. The Iron Age (2450-900 cal a BP) corresponds partly to a highstand at~11 m a.s.l. between 3600 and 2000 cal a BP and partly to a rapid regression of~8 m between 2000 and 1500 cal a BP, and both periods coincide with known human activities along the contemporaneous shoreline. The rapid regression after 2000 cal a BP corresponds to an increase of both regional and local landscape openness and the beginning of a continuous record of crop cultivation.

Diatomite evidence for a small palaeo mountain lake at 3400 m asl, Lesotho, southern Africa

Article

Full-text available

Jul 2024

The Eastern Lesotho Highlands experience an excess of rainfall sufficient to form the country's primary export, supplying the economic hub of southern Africa, Gauteng South Africa. However, there is currently only one natural lake in the country, Letšeng‐la Letsie, and evidence of palaeolakes in the region is therefore of particular interest. This study presents the analysis of a diatomite outcrop from a depression northwest of Mafadi Summit, at 3400 m asl. The presence of diatomite, dominated by the facultative planktonic species Staurosirella pinnata and Staurosira construens and abundant planktonic Aulacoseira ambigua , is indicative of the continuous presence of a shallow lake between ~4600 and 100 cal a bp. Comparative analysis of rainfall for the Mafadi and Letšeng‐la Letsie regions from CHIRPS gridded rainfall data demonstrates sufficient rainfall for a lake of comparable size, if not larger, as Mafadi receives considerably more rainfall than Letšeng‐la Letsie. Analysis of the SRTM 30‐m Digital Elevation Model and Topographic Position Index calculations demonstrate the feasibility of a shallow surface water feature at Mafadi. The conversion of this palaeolake into the contemporary wetland is hypothesized to be the result of post‐industrial warming, possibly augmented by migration of livestock into the Eastern Lesotho Highlands.

Holocene environmental changes inferred from palaeobotanical data of Curonian Lagoon sediments

Article

Full-text available

Jan 2024
BALTICA

Environmental development and water level changes in the south-western part of the Curonian Lagoon are reconstructed based on the results of bottom sediment investigations, including data on lithology, diatoms, pollen, and radiocarbon dating. Three stages have been identified in the ~ 10000-year history of the lagoon’s development. The diatoms suggest that in the Early Holocene, the southern part of the Curonian Lagoon was a shallow freshwater basin, mainly fed by run-off from the continent. During the Middle Holocene, the study area was a marshy coastal zone. Due to a change in hydrological conditions at the beginning of the Late Holocene, it became an open-water part of the lagoon.

A new species of Craspedostauros (Bacillariophyceae) from the west coast of Sweden, with taxonomic and ecological notes on Craspedostauros laevissimus

Article

Full-text available

Jan 2024
BOT MAR

Since its separation from Stauroneis in 1999, several new species of Craspedostauros were discovered in a variety of habitats and geographic locations, adding morphological and phylogenetic data to the investigations of the genus. In a survey of littoral diatoms of Sweden, both on the west and east coasts, two epiphytic stauros-bearing species were encountered and assigned to Craspedostauros following the characteristic features of this genus, including the possession of a stauros narrower than the central area and cribrate areolae. One species is described as new to science; Craspedostauros lateralis sp. nov., and the other is of uncertain identity but bears morphological similarity to C. laevissimus. Caspedostauros lateralis is a marine epiphytic species found in the west coast of Sweden, off Gothenburg city. Based on light and electron microscopy, a detailed description of the morphological and ultrastructural features of these species is given and a comparison of the distinguishing characters with allied species is discussed. Some ecological data and the occurrence of associated species on the host macrophyte are provided.

Are Toxic Substances Always Toxic? Case Studies of Different Organismal Responses Based on Brackish-Water Microphytobenthic Communities from the Baltic Sea

Article

Full-text available

Nov 2023

In this manuscript, we present the results of ecotoxicological tests conducted on the Baltic microphytobenthos community consisting largely of cosmopolitan species showing the responses at the community (taxonomic composition and structure), population (abundance), and cellular (chloroplast shape) levels. The tests were carried out for three chemicals with different modes of action on photosynthetic organisms, i.e., copper (II) chloride (at concentrations of 2·10⁻⁵ g·dm³ and 2·10⁻³ g·dm⁻³), glyphosate in the form of Roundup® (concentrations ranging from 4.2·10⁻² to 8.5 g·dm⁻³), and the ionic liquid [BMIM]Cl (at concentrations of 1.13·10⁻³ g·dm⁻³ and 1.75·10⁻² g·dm⁻³). The results of the study indicate that the responses of microphytobenthos at each level analysed are highly variable and difficult to predict a priori based on experiments performed on single strains. In addition, it was shown that microphytobenthic communities are relatively resistant to the substances tested, which is due to taxonomic richness and the resulting potential for substitution of sensitive taxa by more resistant taxa. The results obtained in the tests also indicate that the number of cells of individual taxa can remain at a similar level or increase over short periods of time despite the deformation of chloroplasts in a numerous group of cells.

The Relationship between Total Mercury, Its Fractions and Species Diversity of Diatom Taphocoenoses Deposited in Surface Sediments (Southern Baltic Sea)

Article

Full-text available

Nov 2023

Mercury is a toxic metal that in excessive amounts negatively affects the human nervous system. It can biomagnify to enrich successive levels of the trophic web with higher and higher concentrations of Hg. Diatoms are cosmopolitan microalgae that represent the base of the trophic web. The objective of this study was to determine the importance of diatoms in the accumulation of Hg in surface sediments in the example of Puck Lagoon (southern Baltic Sea). The study verified the relationship of mercury forms with diatoms’ characteristic salinity groups and individual diatom species. The identified diatom flora permitted the distinguishment of three regions with different salinity preferences. The obtained results suggest that, together with organic matter and fine sediment fraction, diatoms are an important element of the marine environment in accumulating Hg. Area I, dominated by euhalobous and mesohalobous diatom species, was characterized by a high statistically significant correlation of mesohalobous with HgSO4, Hg in complexes with organic matter and HgS. In Area II, associated with the highest Hg concentrations (ca. 100 ng g−1), euhalobous showed a statistically significant linear correlation with HgSO4. In contrast, in Area III, the freshwater diatom community was associated with stable Hg forms. The identified species showed a connection with labile forms of Hg that can undergo biomagnification.

Insights into Diatom Substrate Preferences in the Inter-Tidal Zone of a Subarctic Coast

Article

Full-text available

Oct 2023

Diatoms are reliable environmental bioindicators, but their application in coastal environments remains limited. Substrate has been put forward in the literature as an important variable in determining diatom habitat preferences. This study focuses on benthic diatom assemblages and their relationship with substrate specificity in a subarctic tidal environment, which could be relevant for environmental monitoring and management. A variety of substrates were sampled and physicochemical variables measured in various areas of the Bay of Sept-Îles region (northern Gulf of Saint-Lawrence, Canada). We recorded 606 species at 14 sites from 11 substrate types to determine the associations between diatoms and their habitats. Our results suggest that the variability of assemblages in the bay is the result of a combination of the identified variables (temperature, salinity, and total dissolved solids), explaining 26.5% of the variation, and other unmeasured variables (e.g., nutrients, wave action, and currents). Substrate was not identified as a significant variable in the statistical analyses. However, some common species in the surveyed assemblages appeared to show preferences for the substrates they colonized.

Rhoicosphenia johannessoniae (Bacillariophyceae), a new diatom from the Swedish coast of the Baltic Sea

Article

Sep 2023

Rhoicosphenia is a relatively small diatom genus regarding the number of species and the genus is characterized by its wedge-shaped frustule and heterovalvar structure. It is one of the few genera that is distributed in both marine and freshwater habitats. Few species of Rhoicosphenia are known along the stretched Baltic Sea coast of Sweden. The present study describes a new epiphytic species of Rhoicosphenia from the brackish water of Grisslehamn in the northern part of the Baltic Sea. Rhoicosphenia johannessoniae sp. nov. appears closely related to R. baltica, but differs in having more elongated and protracted base pole, densely packed areolae and a central area located below the central part of the valve. Detailed descriptions of the species based on light and electron microscopy, as well as a comparison with related taxa, are provided. The present work is part of a larger project aiming to study the littoral diatoms of Sweden. The finding of this species, together with other species previously described within the project, will add to our knowledge of the diatom assemblages of the Baltic Sea which seems to have a richer flora than earlier anticipated.

Holocene relative shore‐level changes and development of the Ģipka lagoon in the western Gulf of Riga

Article

Full-text available

Jul 2023

Holocene relative shore-level changes and development of the Ģipka palaeolagoon in the western Gulf of Riga are reconstructed using multiproxy analyses by combining litho-, biostratigraphical and chronological data with remote sensing and geophysical data. The results show the development of the Ģipka basin from the Ancylus Lake/Initial Litorina Sea coastal zone (before c. 9.1 cal. ka BP) to coastal fen (c. 9.1 to 8.4 cal. ka BP) and gradual development of the Litorina Sea lagoon (c. 8.4 to 4.8 cal. ka BP) and its transition to a freshwater coastal lake (c. 4.8 to 4.6 cal. ka BP), fen (c. 4.6 to 4.2 cal. ka BP), and river floodplain (since c. 4.2 cal. ka BP). The highest shorelines of the Ancylus Lake and Litorina Sea were mapped at an elevation of 12–11 and 9 m a.s.l., respectively. A new relative shore level (RSL) curve for the western Gulf of Riga was constructed based on RSL data from the Ģipka area and from nearby Ruhnu Island studied earlier. The reconstruction shows that the beginning of the last marine transgression in the western Gulf of Riga started at c. 8.4 cal. ka BP, and concurred with the 1.9 m RSL rise event recorded from the North Sea basin. Diatom analysis results indicate the existence of the Ģipka lagoon between c. 7.7 and 4.8 cal. ka BP, with the highest salinity c. 6.1 cal. ka BP. During the existence of the brackish lagoon, settlement sites of the Neolithic hunter–gatherer groups existed on the shores of the lagoon in the period c. 6.0 to 5.0 cal. ka BP.

Anthropogenic impact on a seacoast landscape during the last 1300 years in central Latvia, Northeastern Europe

Article

Mar 2023

Human‐induced activities around Lake Lilaste in the central Latvian sandy coastal area have been reconstructed over a 1300‐year period. We use a combination of well‐established geoarchaeological research methods ( ¹⁴ C dating, pollen, nonpollen palynomorphs, REVEALS modeling, diatoms, C/N ratio, magnetic susceptibility, loss on ignition) to study the human impact on the environment. Historical context aids focus on records of resource (e.g., timber) exploitation in the area. The continuous record of human indicator pollen and agricultural landscape suggests this area was suitable for habitation well before the studied time period, likely due to the ecosystem services it provided. Our proxy‐based study, combined with historical background, reveals a significant human impact on the terrestrial environment since the 14th century. Deficiency of trees in the northern outskirts of Riga during the 17th–19th century was likely. Anthropogenic activity has led to both deforestation and change in species composition. Our paleo records indicate recognizable human‐driven legacy in current seacoast landscape.

Late Holocene Vistula River floods recorded in grain size distributions and diatom assemblages of marine sediments of the Gulf of Gdańsk (Baltic Sea)

Article

Full-text available

May 2023
PALAEOGEOGR PALAEOCL

During the large flood of the Vistula River in 2010, the riverine brackish water surface plume extended up to 70 km into the Gulf of Gdańsk (Baltic Sea), leaving a thin layer of medium-grained sand deposits. It inspired a search for palaeoflood records in marine sediments. Thus, we aimed to identify the most useful flood indicators and apply them to reveal palaeoflood records in sediment cores from the Gulf of Gdańsk. The study is based on analyses of surface samples, collected during and one year after the 2010 flood, and two long sediment cores, which were subjected to high-resolution grain size, diatom, and geochemical analyses, while chronology was based on the combined AMS 14C, 210Pb and 137Cs dating. It was found that, in a water depth of less than 30 m, modern large flood deposits were not preserved after a year. Sediment cores retrieved from greater water depths (over 60 m) were composed of sandy mud, and most of the 1 cm thick sediment samples were characterized by unimodal grain size distribution. However, some of the samples were bimodal, with the additional mode in fine-grained fractions, which is interpreted to be the result of direct deposition from riverine flood surface water plume. The diatom assemblages revealed a moderate downcore variability, except for the intervals characterized by bimodal grain size distributions. They contained elevated amounts of benthic oligohalobous (freshwater) and decreased euhalobous and mesohalobous taxa, supporting the likely interpretation of these layers as deposited during river flood events. During the last c. 4 ka, a dozen major flood events were identified. However, their application to flood climate reconstruction is challenging because of relatively frequent and partly unknown changes in major river mouth positions in the past. We suggest that thin deposits of major floods left on the seafloor and subjected to further mixing maybe still recognized using a combination of high-resolution grain size distribution and diatom analyses supplemented by a good understanding of the depositional system history.

Biodiversity of the benthic diatom flora in the coastal zone of the Gulf of Gdańsk: a case study of the Gdynia–Sopot transect

Article

Full-text available

Jun 2022

The objective of this study is to determine microhabitat preferences of benthic species occurring in epilithic (living on stones), epipsammic (growing on sand), epipelic (growing on mud) and epiphytic (living on seagrass) assemblages of the shallows of the Gulf of Gdańsk (southern Baltic Sea). The study material was collected from 19 sites along the Gdynia–Sopot coastal zone, including the Port of Gdynia. Most of the identified diatom taxa were observed in two or three microhabitats. However, diatom species living in only one type of microhabitat and those occurring in all analyzed microhabitats were also recorded. Autecological preferences of the identified diatoms indicate organic pollution of the coastal zone of Gdynia and Sopot. However, a higher frequency of α-mesosaprobionts and polysaprobionts indicates an increase in organic pollution in the Port of Gdynia and Marina Sopot, which is associated with intense port activity and large tourist traffic.

The pennate benthic diatoms of the sand beach of Kruglaya Bay (the Black Sea)

Article

Full-text available

Aug 2022

For the first time in the Kruglaya Bay of the Black Sea, 25 taxa of Bacillariophyta from 17 genera were found, three of them were new for the Crimea and the Black Sea Halamphora tenerrima, Amphora tenuissima, and Navicula antonii. Marine (40%), coastalbrackish (32%) and boreal-tropical (32%), arctic-boreal-tropical (24%), boreal and cosmopolitan (20% and 16%, respectively) prevailed. The morphological characteristics of the species in the SEM (scanning electronic microscope) and LM (light microscope), as well as the occurrence, ecology, phytogeography, and general distribution in various regions of the World Ocean are given.

Holocene relative water level and storminess variation recorded in the coastal peat bogs of the Vistula Lagoon, southern Baltic Sea-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Article

Full-text available

Oct 2022
QUATERNARY SCI REV

The history of regional sea-level changes is critically important for building global environmental reconstruction models and identifying major driving forces. The coastal peatlands located on the terraces of the Vistula Lagoon (Gulf of Gda nsk, southern Baltic Sea) are one of the most valuable, and not yet fully explored, archives of the regional history of sea-level and storminess changes during the middle and late Holocene. The comprehensive analysis of peat and gyttja allowed establishing radiocarbon calibrated time series of stable carbon isotope composition (d 13 C), pollen and diatom data. The results indicate that the sea-level increased from~20 to 8 m below present sea level between 9000 and 7000 yr b2k at an average rate of~6 mm/year. Around 5000 yr b2k, the sea-level was~2.5 m lower than at present, which indicates a decrease in the rate of sea-level rise to~2.75 mm/year between 7000 and 5000 yr b2k. During the last 5000 years, the sea-level had risen at~0.5 mm/year to the present position. Changes in brackish diatoms, Pediastrum sp. concentrations, and maxima of d 13 C suggest ten periods of increased rates of sea-level rise and storminess between 7000 and 1500 yr b2k. Increased sea-levels and stormy surges on the peat surface occurred mainly during cold periods or the periods of transitions. These observations are in good agreement with climate fluctuations in the Northern Hemisphere related to the variations in total regional solar irradiation.

Holocene relative sea level changes in the Västervik-Gamlebyviken region on the southeast coast of Sweden, southern Baltic Sea

Article

Full-text available

Oct 2022
BOREAS

We reconstruct the Holocene shore displacement of the Västervik-Gamlebyviken area on the southeast coast of Sweden, characterised by a maritime cultural landscape and archaeological significance since the Mesolithic. Sediment cores were retrieved from four lake basins that have been raised above sea level due to the postglacial land uplift and eustatic sea level changes after the melting of the Fennoscandian Ice Sheet. The cores were radiocarbon dated and analysed for loss on ignition and diatoms. The isolation thresholds of the basins were determined using LiDAR data. The results provide evidence for the initiation of the first Littorina Sea transgression in this area at 8.5 thousand calibrated years before present (cal. ka BP). A relative sea level rise by ∼7 m a.s.l. is recorded between 8.0 and 7.5 cal. ka BP with a highstand at ∼22 m a.s.l. between 7.5 and 6.2 cal. ka BP. These phases coincide with the second and third Littorina Sea transgressions, respectively, in the Blekinge area, southern Sweden and are consistent with the final deglaciation of North America. After 6.2 cal. ka BP, the relative sea level dropped below 22 m a.s.l., and remained at ∼20 m a.s.l. until 4.6 cal. ka BP coinciding with the fourth Littorina Sea transgression in Blekinge. From 4.6 to 4.2 cal. ka BP, the shore displacement shows a regression rate of 10 mm a−1 followed by a slowdown with a mean value of 4.6 mm a−1 until 1.6 cal. ka BP, when the relative sea level dropped below 3.3 m a.s.l. The Middle to Late Holocene highstand and other periods of minor sea level transgressions and/or higher salinity between 6.2 and 1.7 cal. ka BP are attributed to a combination of warmer climate and higher inflow of saline water in the southern Baltic Sea due to stronger westerlies, caused by variations in the North Atlantic atmospheric patterns.

Biodiversity of the benthic diatom flora in the coastal zone of the Gulf of Gdańsk: a case study of the Gdynia–Sopot transect

Article

Full-text available

Sep 2022
OCEANOL HYDROBIOL ST

Effects of the Ionic Liquid [BMIM]Cl on the Baltic Microphytobenthic Communities

Article

Full-text available

Sep 2022

Ionic liquids (IL) are regarded as the solution to the modern world’s need to create and use compounds that exhibit a range of desirable properties while having a low environmental impact. However, recent reports are shattering the image of ionic liquids as environmentally friendly substances, especially in relation to the aquatic environment, revealing their potentially toxic effects. To assess the potential environmental impact of ILs, we conducted an experiment involving 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), a substance considered to be the least hazardous among the imidazolium chloride ILs, on Baltic microphytobenthic communities. Microphytobenthos collected from the environment was tested under controlled laboratory conditions, and both the cell counts and the chloroplast condition were used as endpoints. It was shown that [BMIM]Cl at concentrations of 10−3 and 10−2, considered safe based on a cumulative impact assessment, has a negative effect on the condition of the microalgal cells and causes a reduction in population size. Although, under the influence of [BMIM]Cl, only a small proportion of the species was eliminated from the communities, only two species among those important to the communities showed resistance to this compound and eventually began to dominate the communities.

Distribution of marine benthic diatoms on the coasts of the sea of Marmara and their responses to environmental variables

Article

Jul 2022
J MARINE SYST

The Sea of Marmara, located in northwest Turkey, comprises challenging environmental conditions and is an important bridge between the Black Sea and the Aegean Sea. In this study, we assessed the trophic situation of the coasts of the Sea of Marmara using the benthic diatom composition and their relation to the environmental variables in the spring and autumn of 2019 and 2020. A total of 120 samples were collected and 452 species were observed; Navicula Bory and Nitzschia Hassal were represented with the highest numbers of taxa. Analysis of Similarity (ANOSIM) revealed that diatom communities differed significantly between the spring-autumn periods and years. Canonical Correspondence Analysis (CCA) showed that diatoms grouped underwater temperature, salinity, dissolved oxygen, and TIN influence. TRIX observations revealed a highly mesotrophic-eutrophic status along the coasts. Our study contributes to the knowledge of diatom diversity, distribution and community changes in spring and autumn on the coasts Sea of Marmara. Our findings suggest that marine benthic diatoms could be used as eutrophication indicators in the coastal waters for long-term monitoring with the support of environmental parameters.

Copper chloride (II) effect on the composition and structure of marine microphytobenthic communities

Article

Full-text available

Jun 2022
ENVIRON MONIT ASSESS

To assess the temporary effects of the increased copper ion inflow on estuarine microphytobenthic communities, ecotoxicological tests were conducted using natural microphytobenthic assemblages obtained from an artificial substratum exposed to the waters of the southern Baltic Sea (Gulf of Gdańsk). The applied copper ion concentrations reflected permitted copper values established for waters of a good ecological status (2·10–5 g Cu·dm⁻³), and the maximum copper concentrations which, according to the current environmental regulations, are allowed to be discharged into the environment (2·10–3 g Cu·dm⁻³). In the studied communities, diverse responses of single species to CuCl2 exposure were recorded, including both growth inhibition and stimulatory effects as well. Despite the shift in the community composition and structure, total cell number remained at a similar level. The results of our investigations suggest that microphytobenthic assemblages are resistant to CuCl2 which is facilitated by the shift in the community composition resulting from the increasing cell number of copper tolerant species.

Studying biodiversity–ecosystem function relationships in experimental microcosms among islands

Article

Full-text available

Mar 2022
ECOLOGY

Ecological studies on islands have provided fundamental insights into the mechanisms underlying biodiversity of larger organisms, but we know little about the factors affecting island microbial biodiversity and ecosystem function. We conducted a field experiment on five Baltic Sea islands where we placed aquatic microcosms with different levels of salinity mimicking environmental stress and allowed diatoms to colonize the microcosms via the air. Using structural equation models (SEM), we investigated the interconnections among environmental and dispersal‐related factors, diatom biodiversity, and ecosystem productivity (represented by chlorophyll a concentration). We also tested whether the body size structure of the community influences productivity together with biodiversity. In SEMs, we found no relationship between species richness or evenness and productivity. However, productivity increased with increasing mean body size of species in the communities. The effects of environmental stress on both biodiversity and ecosystem productivity were highlighted as species richness and evenness declined, whereas productivity increased at the highest salinity levels. In addition to salinity, wind exposure affected both biodiversity metrics and productivity. This study provides new insights into microbial community assembly in a field experimental setting and the relationship between biodiversity and ecosystem function. Our results indicate that salinity presents a strong abiotic filter, leading to communities that may be species poor, yet comprise salinity‐tolerant and relatively productive species at high salinity. Our findings also emphasize the importance of mean community body size in mediating the effects of environmental conditions on productivity and suggest that this trait should be considered more broadly in biodiversity–ecosystem function studies.

Epipelic and epipsammic microalgae responses to environmental parameters: the Black Sea case study (the Gulf of Odesa, Ukraine)

Article

Dec 2021

Being part of autotrophic system in the sandy beaches epipelic and epipsammic microalgae play an essential role in primary production formation and transferring elements through the food chain. Acting as mixotrophs, they also participate in reduction of organic matter. But it is still less known about their response to pull of environmental factors. In particular, what is the range of main environmental parameters in sand supralittoral. The aim of this paper was to see the interaction between microalgae abundance and 14 environmental factors during field multifactoral experiment: 5 parameters describing sand grain composition, nutrients, temperature and salinity of water, hydrodynamics and water toxicity. We also analyzed the biodiversity of epipelic and epipsammic microalgae and their distribution in the North Western Black Sea. We revealed 76 taxa of microalgae: 39% epipelic and 27% epipsammic. The priority factor for psammon algal community in any season is size of sand grains and dissolved silicates. Other variables depend on the season: while in summer, inorganic nitrogen (nitrates and nitrites) affects the microphytes more intensively than others, in autumn it is replaced by organic nitrogen and silty fraction.

Late-Holocene relative sea-level changes and palaeoenvironment of the Pre-Viking Age ship burials in Salme, Saaremaa Island, eastern Baltic Sea

Article

Dec 2021

Two unique Pre-Viking Age ship burials were found from Salme village, Saaremaa Island, eastern Baltic Sea, containing remains of seven men in the smaller and 34 men in the larger ship. According to the archaeological interpretations, these ships belonged to a viking crew possibly from the Stockholm-Mälaren region, eastern Sweden. Geoarchaeological research was conducted in the area to reconstruct Late-Holocene relative sea-level (RSL) changes and shoreline displacement to provide environmental context to these burials. In this paper we present a Late-Holocene shore displacement curve for the Saaremaa Island and GIS-based palaeogeographic reconstructions for the Salme area. The curve shows an almost linear RSL fall from 5.5 to 0.8 m a.s.l. between 1000 BC and 1300 AD with an average rate of 2 mm/year. A slowdown in regression may be attributed to accelerated sea-level rise after the Little Ice Age and during the industrial period, being consistent with the tide-gauge measurements from the 20th century. Palaeogeographic reconstructions indicate the existence of a strait in the Salme area during the burial of the ships. The eastern part of the strait with water depth up to 2.8 m was about 80–100 m wide. The relatively steep and wind-protected shores in that part of the strait were probably the best places in the area for landing the viking ships. According to sedimentological evidence and diatom data, the narrowing of Salme palaeostrait occurred between 1270 and 1300 AD. Salme I and II ships were buried at 650–770 AD into the sandy-gravelly coastal deposits which had accumulated there in the open coastal zone about 710–450 years earlier. Reconstructions show that the ships were located about 2–2.5 m above coeval sea level and more than 100 m from the coastline. Thus, both ships were probably moved from the shore to the higher ground for burial.

Sediment sequence at Muhos, western Finland – a window to the Pleistocene history of the Scandinavian Ice Sheet

Article

Full-text available

Nov 2021
BOREAS

In this study, we analysed a ˜54‐m sediment core consisting of Quaternary sediments overlying the Neoproterozoic Muhos Formation in central western Finland, adjacent to the Gulf of Bothnia. The sediments recovered were logged, and their sedimentological characteristics defined. Two fine‐grained sediment units were subjected to biostratigraphical studies using pollen and diatom analyses. In addition, two sand‐rich units and a wooden stick were dated by the optically stimulated luminescence (OSL) and 14C‐AMS methods. The core sediments were divided into six units, where several diamicton, sand and gravel, and silt‐and‐clay‐dominated beds were studied. The results indicate that the sediment succession of the core beneath the Holocene Litorina Sea and the Ancylus Lake sediments of the Baltic Basin were deposited in glacial and lacustrine environments that existed in the Oulu River valley during the time period between the Saalian glaciation (MIS 6) and the Holocene. The stratigraphical evidence, supported by the OSL ages, suggests that the Scandinavian Ice Sheet (SIS) entered the Muhos area during the Saalian glaciation, and at least during three separate time intervals in the Weichselian stage. Stratigraphically controlled and age‐bracketed evidence shows that the first Weichselian SIS advance extended further south in the eastern part of Fennoscandia than previously estimated, and that this ice growth phase occurred during the Early Weichselian Herning Stadial (MIS 5d). The subsequent ice growth phases occurred during the Middle (MIS 4) and Late (MIS 2) Weichselian substages. The lacustrine and littoral sediments of the Muhos core were correlated with the late Eemian interglacial (MIS 5e) and two Weichselian interstadials (MIS 5c and MIS 3).

Novel Diatoms (Bacillariophyta) from tropical and temperate marine littoral habitats with the description of Catenulopsis gen. nov., and two Catenula species

Article

Oct 2021

Regions with high levels of biodiversity, which mostly correspond to tropical regions, can be treated as treasuries of endemism, even for single-celled life forms. Learning about these areas, and the species present in them, is key to understanding the processes that govern their emergence and sustainability. This paper is a contribution towards revealing the biodiversity of marine benthic diatom species of the world. The samples used in this paper were taken from East Java (Indonesia), Nosy Be (north-west Madagascar) and the Tagus estuary (Portugal). We describe a new diatom genus, Catenulopsis, and propose the first species of the genus from Nosy Be, named Catenulopsis catenulafalsa. We also describe two new Catenula species, one from Java (Catenula javanica) and the other from Portugal (Catenula brotasiae). The paper also discusses the characteristics of Catenula adhaerens and variations in the species across geographic space. We characterize the morphological variation of C. adhaerens in samples from equatorial West Africa, South Africa, Portugal, Japan, Madagascar and Indonesia.

Вплив екологічних факторів на мікроводорості псамону на прикладі Одеської затоки (Чорне море, Україна)

Article

Full-text available

Sep 2021

Досліджено вплив екологічних факторів на морські мікроводорості піщаного узбережжя Одеської затоки. Незважаючи на достатню вивченість впливу фізичних та хімічних факторів середовища на мікроводорості, процеси, що відбуваються на піщаній супраліторалі в регіоні Чорного моря, потребують додаткових досліджень. В ході польового багатофакторного експерименту на узбережжі Одеської затоки досліджено взаємозалежність між чисельністю мікроводоростей та 14 екологічними факторами: низка параметрів, що визначають гранулометричний склад піску, біогенні елементи, температуру, солоність води, гідродинаміку та токсичність. Проаналізовано таксономічний склад мікроводоростей фітопсамону та їх розподіл у різних біотопах у холодноводний та тепловодний періоди. Пріоритетним фактором для угруповання фітопсамону в будь-який сезон є розмір піщинок та концентрація розчиненого кремнію. Інші параметри залежать від пори року: влітку сполуки мінерального азоту (нітрати та нітрити) є пріоритетним фактором, восени цю роль відіграють органічний азот та мулиста фракція піску.

DNA metabarcoding reveals differences in distribution patterns and ecological preferences among genetic variants within some key freshwater diatom species

Article

Jul 2021
SCI TOTAL ENVIRON

Our study evaluates differences in the distribution and ecology of genetic variants within several ecologically important diatom species that are also key for Water Framework Directive monitoring of European rivers: Fistulifera saprophila (FSAP), Achnanthidium minutissimum (ADMI), Nitzschia inconspicua (NINC) and Nitzschia soratensis (NSTS). We used DADA2 to infer amplicon sequence variants (ASVs) of a short rbcL barcode in 531 environmental samples from biomonitoring campaigns in Catalonia and France. ASVs within each species showed different distribution patterns. Threshold Indicator Taxa ANalysis revealed three ecological groupings of ASVs in both ADMI and FSAP. Two of these in each species were separated by opposite responses to calcium and conductivity. Boosted regression trees additionally showed that both variables greatly influenced the occurrence of these groupings. A third grouping in FSAP was characterized by a negative response to total organic carbon and hence was better represented in waters with higher ecological status than the other FSAP ASVs, contrasting with what is generally assumed for the species. In the two Nitzschia species, our analyses confirmed earlier studies: NINC preferred higher levels of calcium and conductivity. Our findings suggest that the broad ecological tolerance of some diatom species results from overlapping preferences among genetic variants, which individually show much more restricted preferences and distributions. This work shows the importance of studying the ecological preferences of genetic variants within species complexes, now possible with DNA metabarcoding. The results will help reveal and understand biogeographical distributions and facilitate the development of more accurate biological indexes for biomonitoring programmes.

New Records of the Diatoms (Bacillariophyceae) from the Coastal Lagoons in Korea

Article

Full-text available

Jun 2021

Lagoons are natural bodies of water that are isolated from the sea due to the development of a sand bar or spit. Each lagoon has distinct ecological characteristics, and these sites also serve as popular tourist attractions because they are common habitats for migratory birds and are characterized by beautiful natural scenery. Lagoons also have distinct ecological characteristics from those of their associated estuaries, and there are active research efforts to classify, qualify, and quantify the high biodiversity of lagoons. The lagoons in Korea are primarily distributed in the East Sea, and are represented by Hwajinpo, Yeongrangho, and Gyeongpoho. Here, we report the discovery of 11 un-recorded diatom species (Diploneis didyma, Mastogloia elliptica, Cosmioneis citriformis, Haslea crucigera, Pinnularia bertrandii, Pinnularia nodosa var. percapitata, Gyrosigma sinense, Gomphonema guaraniarum, Gomphonema italicum, Navicula freesei, Trybionella littoralis var. tergestina) among samples collected from the Hwajinpo, Hyangho, Maeho, Gapyeongri wetland, Cheonjinho, and Gyeongpoho lagoons in Korea during a survey from 2018-2020. We present the taxonomic characteristics, ecological information , habitat environmental conditions, and references for these 11 species.

Diatom sedimentary assemblages and Holocene pH reconstruction from the Canadian Arctic Archipelago's largest lake

Article

Jun 2021

The Arctic has warmed significantly over the past decades. However, the evolution of Arctic climate during the Holocene remains to be clarified in more detail, and regional factors controlling aquatic ecosystem evolution need to be better defined to grasp the sensitivity of lakes to rapid environmental change. Nettilling Lake was studied for changes in sedimentary diatom assemblages over the last 5 000 years. Lake water pH was reconstructed by applying a diatom-based lake water pH inference model. We hypothesized that the changes in diatom assemblages were driven by variations in lake water transparency and attendant water turbidity associated with the input of fine suspended solids from glacial meltwaters. Reduced underwater light resulted in greater abundance of planktonic over benthic taxa from ca. 5 000 to 3 000 yrs. cal. BP, followed by less turbid conditions and proliferation of benthic taxa during regional cooling. The lake water was slightly alkaline throughout the Holocene, ranging between pH 7.1 and 7.7. Our results support the notion that hydrological processes, dependent on climate variations, have a first-order influence on the regulation of the lake water pH through glacial meltwater inputs, which will likely continue to control the lake's long-term chemical and biological evolution. RÉSUMÉ

Exploring Multiple Aspects of Taxonomic and Functional Diversity in Microphytobenthic Communities: Effects of Environmental Gradients and Temporal Changes

Article

Full-text available

May 2021

Biodiversity has traditionally been quantified using taxonomic information but the importance of also considering its functional characteristics has recently gained an increasing attention among microorganisms. However, studies exploring multiple aspects of taxonomic and functional diversity and their temporal variations are scarce for diatoms, which is one of the most important microbial groups in aquatic ecosystems. Here, our aim was to examine the taxonomic and functional alpha and beta diversities of diatoms in a coastal rock pool system characterized by a naturally high environmental heterogeneity. We also investigated the temporal differences in the diversity patterns and drivers. The relationship between the species richness and functional dispersion was temporally coherent, such that species-poor communities tended to be functionally clustered. The trend between the species richness and taxonomic uniqueness of community composition was temporally inconsistent, changing from negative to non-significant over time. Conductivity or distance to the sea or both were key determinants of species richness, functional dispersion, and uniqueness of community composition. The increase of community dissimilarity with an increasing environmental distance was stronger for the taxonomic than the functional composition. Our results suggest that even minor decreases in the species richness may result in a lowered functional diversity and decreased ecosystem functioning. Species-poor ecosystems may, however, have unique species compositions and high contributions to regional biodiversity. Despite changing the species compositions along the environmental gradients, communities may remain to have a high functional similarity and robustness in the face of environmental changes. Our results highlight the advantage of considering multiple biodiversity metrics and incorporating a temporal component for a deeper understanding of the effects of environmental changes on microbial biodiversity.

Cocconeis tsara sp. nov., C. santandrea sp. nov. and allied taxa pertaining to the new section Loculatae

Article

Full-text available

Feb 2021

The genus Cocconeis is highly diverse and composed of several groups with distinctive morphologies. Several Cocconeis, characterized by complex areola occlusions, are here grouped under the new section Loculatae. The complex loculate are-olae are either present on both valves, or most often only on the sternum valve (SV). Among the Loculatae taxa, some were described as varieties of Cocconeis scutellum, whereas others were assigned species rank. Critical SEM examination is required to correctly discriminate members of this section. Cocconeis tsara sp. nov. and C. santandrea sp. nov. are marine tropical benthic diatoms with loculate areolae justifying their membership to the proposed section. Based on ultrastructure, a cladistic analysis is performed to determine the relationships between these taxa. A traditional dichotomous tree based on the most particular features encountered on this group is constructed to aid in species determination. Several of the Loculatae taxa are epiphytic, one was observed as epizoic. The necessity of high resolution SEM to discern details of the SV areola occlusions and the raphe valve valvocopula (RVVC), and the nomenclatural descriptive terms used by authors, are discussed to better compare recent and historical descriptions.

Checklist of marine diatoms from the Turkish coastal waters with updated nomenclature

Article

Full-text available

Jan 2021

Marine diatom research in the coastal waters of Turkey started nearly two centuries ago. In the last decades, in-creasing numbers of contri-butions extended the knowledge of the marine phytoplankton. While sev-eral studies dedicated to planktonic forms and the checklists published con-cerning on the phytoplank-ton, relatively low numbers of benthic diatom studies were performed. Therefore, this is the first detailed list of the marine diatoms in-cluding both planktonic and benthic forms in Turkish coasts. This paper brings up the checklist of the past re-search referring to the au-thors in the last two centu-ries within the scope of the latest nomenclature. A total of 767 taxa (species, varie-ties and forms) belonging to 183 genera were listed. This study focussed into the study areas according to the reviewed literature and showed that many areas are yet to be investigated.

Littorina and post-Littorina sedimentological processes in the Odra Channel in light of multidisciplinary investigations of a sediment core, Pomeranian Bay, southern Baltic Sea

Article

Oct 2020
QUATERN INT

A multi-proxy study was performed on a gravity core supplemented by acoustics profiles and new radiocarbon dates of macrofossils found in the sedimentation history of the Odra Channel during the Holocene. The channel is located in the western part of Pomeranian Bay and was shaped by a pre-Odra river that flowed northwest along the Peene valley and the eastern part of Rügen Island during a drop in Yoldia Sea level. The acoustic profiling enabled identification of glacial till, the Baltic Ice Lake and Littorina sediments. The studied core penetrated only marine sediments deposited during Littorina and Post-Littorina stages and was the subject of grain size, geochemical and diatom analyses. The age of appearance of a marine environment in the studied area was estimated at 7200 yrs BP. The performed studies enabled division of the core into three phases of environmental evolution: the Littorina I phase occurred during the time span 7200–6000 yrs BP and is described as a shallow water brackish basin with a low rate of sea level rise and favourable conditions for biogenic production, the Littorina II phase dated at 6000–3800 yrs BP reflects a deep marine environment with relatively high salinity and greater current velocity, and the last phase, Post-Littorina, covered the last 3800 yrs BP and turned out to be a strongly energetic environment with decreasing salinity. The change from Littorina II to Post Littorina phase correlates clearly with a change in the acoustic reflection. Core analyses could be associated with extreme stormy cold events known as Bond events dated at 5900–5500 yrs BP and 4200 yrs BP evidencing the final destruction of the Odra Bank barrier.

Relative sea level changes and glacio-isostatic modelling in the Beagle Channel, Tierra del Fuego, Chile: Glacial and tectonic implications

Article

Full-text available

Nov 2020

Keywords: MIS 5e Holocene Beagle Channel Coastal sections Peat Lacustrine Marine and lagoon sediments Vertical tectonics Age of deglaciation Relative sea level changes Glacio-isostatic modelling Ice-sheet thickness a b s t r a c t The Beagle Channel crosses the southernmost tip of South America (Tierra del Fuego), connecting the South Atlantic with the Southeastern Pacific. Raised beaches occur up to 10 m above mean sea level (m a.m.s.l.), especially along the northern (Argentinian) shore, and have been dated using marine shells. The southern (Chilean) shore is well-known for its abundance of shell middens at different levels above the present shore, particularly along the island of Isla Navarino, but the relative sea level history in this glacially impacted landscape has not previously been investigated. In this study we present postglacial relative sea level changes on Isla Navarino, based on sediment cores from six lagoons, bogs or lakes, and stratigraphic investigations of three open sections, of which one is of MIS 5e age. In addition, one core from a lagoon in the southwestern Beagle Channel has been analysed and a system of terraces was mapped in the northwestern Beagle Channel. The analyses of the core sites have resulted in two tentative relative sea level curves, displaying a rapid sea level rise at 8500À6500 cal yr BP, amounting tõ 10 and 14 m in eastern and western Isla Navarino, respectively, and reaching levels of~8 and > 10 m, respectively, followed by a slow relative sea level fall. Our sea level observations have been compared with a range of modelling results of glacial-isostatic adjustments (GIA) for estimating timing of degla-ciation and ice sheet thicknesses. Based mainly on the GIA modelling of the altitude of the MIS 5e beach sediments, situated at 13 m, we can conclude that no other uplift than GIA is needed to explain their altitude. Regarding the modelling of postglacial sea levels we can conclude that no model has been found that satisfies all of the observational evidence, but that deglaciation most likely preceded Northern Hemisphere main deglaciation by at least 3 kyr, which agrees with the deglaciation age of Isla Navarino (>16 000 cal yr BP). In addition, our model runs imply that the Patagonian and Tierra del Fuego ice sheet thicknesses were in the order of~1500 m.

The Planktic and Benthic Communities of the Russian Part of the South-Eastern Baltic Sea

Chapter

Jan 2025

The current state and changes in biological communities of the Russian part of the South-Eastern Baltic Sea during two first decades of twenty-first century is considered. In phytoplankton, some typical cold-water dominants have been lost from the spring complex of species and the productivity of summer phytoplankton has been 4–7 times higher in some years. The species composition and spatial distribution of zooplankton in the shallow water zone are analyzed. For the first time, distribution patterns for macroalgae communities are determined for the Russian South-Eastern Baltic Sea, including biotopes dominated by perennial red alga Furcellaria lumbricalis. It is shown that the maximum depth of macroalgae growth in the study area has shifted toward lower depths in comparison with those characteristics of the Baltic Sea. The location, composition, and structure of bottom macrozoobenthos communities are described. For the first time for the study area, lists of species of phytoplankton, zooplankton, and phytobenthos are presented. The revised list of macrozoobenthos species is also provided.

Shallow marine diatom assemblage change during the past million years in the Nishimikawa Plain, Aichi Prefecture, Japan愛知県西三河平野における過去100 万年間の浅海生珪藻化石群集の変遷

Article

Mar 2024

Diatom assemblages recovered from three drilling cores, GS-HKN-1, GS-NSO-2 and TK No.1 cores, drilled in the Nishimikawa Plain, Aichi Prefecture, Japan, are investigated. The diatom assemblages from each core comprise a series of repeating assemblages dominated by marine and brackish-water diatoms and freshwater diatoms. Diatom zones were defined in each core (zones HKN1-1 to 8, NSO2-1 to 4 and TK1-1 to 6, respectively, from lower to upper), and the diatom assemblages in each zone were documented and their depositional environments were also estimated. The age of the marine intervals, which consist mainly of marine and brackish-water diatom assemblages, and their correlation with oxygen isotope stages (MIS) indicate that at least nine marine intervals are intercalated in the sediments of the Nishimikawa Plain over the past million years. The last occurrence of Cyclotella stylorum in the late Early Pleistocene, Lancineis rectilatus in MIS15 or MIS17, Diploneis cf. bombus in MIS11, and Paralia fenestrata only occurs above MIS19. The biostratigraphy of these diatom fossils can provide a useful stratigraphic reference for the Pleistocene in this area. Microscopic photographs of the key diatom fossils are illustrated, together with a list of references and illustrations for the basis of identification.

Diatoms in Saline Lakes Paleoclimate and Paleoecology Interpretations

Article

Jul 2017

E. J. Ekdahl

Average global temperatures are predicted to rise over the next century and changes in precipitation, humidity, and drought frequency will likely accompany this global warming. Understanding associated changes in continental precipitation and temperature patterns in response to global change is an important component of long-range environmental planning. For example, agricultural management plans that account for decreased precipitation over time will be less susceptible to the effects of drought through implementation of water conservation techniques. A detailed understanding of environmental response to past climate change is key to understanding environmental changes associated with global climate change. To this end, diatoms are sensitive to a variety of limnologic parameters, including nutrient concentration, light availability, and the ionic concentration and composition of the waters that they live in (e.g. salinity). Diatoms from numerous environments have been used to reconstruct paleosalinity levels, which in turn have been used as a proxy records for regional and local paleoprecipitation. Long-term records of salinity or paleoprecipitation are valuable in reconstructing Quaternary paleoclimate, and are important in terms of developing mitigation strategies for future global climate change. High-resolution paleoclimate records are also important in groundtruthing global climate simulations, especially in regions where the consequences of global warming may be severe.

Stochastic frontier analysis of catfish (Clarias gariepinus) aquaculture agribusiness for sustainable fisheries development: Evidence from Nigeria

Article

Full-text available

Jun 2021

Dicta Ovuevuraye Ogisi

Technical efficiency assessment and enhancement is critical to sustainable fisheries development in Nigeria. This study examines stochastic frontier of catfish aquaculture agribusiness for sustainable fisheries development. Purposive sampling technique was employed to select 110 catfish farmers in areas with high density catfish farms. Primary data were collected directly from catfish farmers using structured questionnaire. The analytical tools used were descriptive statistics, net farm income, stochastic frontier production function (SPF) and t-statistics. The result shows that most of the catfish farmers were young people within the productive age of 40-49 years. Catfish farmers had obtained various levels of formal education. Finding shows that feeds cost was the highest variable cost (72.75%). Feed had a positive and significant relationship (P<0.05) with catfish output. Mean technical efficiency is 53.49%. The estimated variance (δ2s=0.2125) is statistically significant (P<0.05), indicating that profit inefficiency is highly significant among catfish farmers. Estimated Gamma (γ) value of 0.26 implies that 26% of the total variation in catfish profit efficiency is due to the joint effect of technical inefficiency factors. The most significant efficiency factors are fish feed and pond size. The age and educational status of farmers are the most important determining factors of inefficiency in catfish production system. Lack of finance was the most serious constraint faced by catfish farmers. The study recommended that catfish farmers should form cooperative unions to facilitate their access to cooperative funding.

Etude de la pertinence des peuplements du microphytobenthos estuarien pour la mise en place d'un bio-indicateur de la qualité des eaux de transition

Technical Report

Full-text available

May 2022

In order to establish the ecological status of transitional water bodies, the European Water Framework Directive (WFD) is based on the evaluation of a certain number of biological quality elements, as well as physicochemical parameters supporting biology. As phytoplankton monitoring is not considered relevant due to the high turbidity characterizing the large estuaries in mainland France and overseas departments (French Guiana), the possibility of using microphytobenthos as a biological indicator of the ecological status of estuaries is being explored as a possible alternative. This activity report presents all the work carried out in 2021 within the framework of an OFB / University of Nantes agreement concerning estuarine microphytobenthos, summarizes all the work carried out since the start of the project and concludes the project. This work is divided into two parts. The first part concerns the micro-scale study (cm2) based on variations in the diversity and biomass of communities in relation to natural and anthropogenic pressures. The objective is to explore the possibility of developing a bio-indicator of the quality of estuarine water which draws inspiration from work carried out for freshwater. In 2021, we analyzed the data collected during the 2018 field campaigns in the estuaries of La Penzé, Morlaix, and the Seine. We related the data of microphytobenthos biomass estimated by the concentration of chlorophyll-a, also adding the data from 2016. We were able to identify the role of nutrients and secondarily macrofauna. The highest biomasses were observed for the site with the highest concentrations of ammonium, phosphates, and silicates. This confirmed the idea put forward in the article by Oiry & Barillé (2021) of microphytobenthos as a bioindicator of nutrient concentrations, in particular ammonium and nitrates. With this in mind, we wrote a manuscript describing an ecological niche-based method to identify which taxa have the best bioindication potential for nitrates and ammonium. The principle was outlined in last year's report (Oiry et al. 2020). We therefore now have the ability to assign an indicator value and ecological sensitivity to taxa of microphytobenthos by analogy with what is done for freshwater. We are, however, limited by the available dataset, which is 2-3 orders of magnitude smaller than what exists in freshwater. The range of environmental data, in particular nutrients, does not reach the values described for highly anthropized European estuaries. We, therefore, believe that we have laid the foundations to develop a bio-indicator based microphytobenthos communities. The last objective of the micro-scale actions was to update the database of benthic diatoms in mainland France. The current database includes 11,511 taxonomic entries found in 49 different references. The time period of the references used in this database now extends from 1888 to 2019. We have reconfigured the data in the Darwin Core Archive format, which is a standard for computer data on biodiversity. This will allow the database to be uploaded to the Global Biodiversity Information Facility (GBIF, https://www.gbif.org/) and to prepare a publication in the Biodiversity Data Journal (https://bdj.pensoft.net ). The second part concerns the macro-scale (km2) study of the microphytobenthos (MPB) using satellite remote sensing. We continued the observation of the MPB of the 42 Transitional Water Bodies (TWB) using the Sentinel-2 constellation of the European Space Agency which had been carried out for the year 2018 (Oiry & Barillé, 2021). This year we analyzed all the images available for 2019 and 2020, and therefore had 3 years of data. For each TWB and each date available, the biomass of MPB (estimated by the NDVI vegetation index) and the % cover of intertidal zones by MPB were recovered. Thus for each TWB, the frequency distribution of these two variables was obtained. We thus determined the 90 percentile (P90) of these two variables for each TWB. TWBs composed mainly of sandy sediments were treated separately from those composed mainly of muddy sediments. The median P90 for each estuary was compared to a reference P90 selected from estuaries that had the lowest median concentrations of nitrogenous nutrients from the Naïades platform (naiades.eaufrance.fr). An Ecological Quality Ratio (EQR) is thus proposed which combines the two metrics with a weighing principle. The EQR was applied to the 42 TWBs in mainland France.

Transfer of Fragilaria atomus Hust. to the genus Stauroforma (Bacillariophyta) based on observation of type and newly collected material

Article

Dec 2013

Fragilaria atomus was described from a brackish water lagoon in southern Finland and has subsequently been reported from several localities worldwide. However, due to its small size, it can be easily mistaken with other small, morphologically similar araphid diatoms. To clarify the morphological, metric and structural features of the species, lectotype material from BRM (Hustedt's diatom collection) and specimens from salt marshes in Brazil were studied using light and scanning electron microscopy. Fragilaria atomus is compared to seven morphologically similar taxa belonging to Fragilaria, Stauroforma and Psammoneis. The results revealed that some important features of Fragilaria (discoid closing plates, rimoportulae and spines) are not present in F. atomus. The absence of these structures, together with the opposite striation pattern, round areolae, features of the apical pore field, and reduced or absent sternum, suggest that a transfer of F. atomus to Stauroforma is appropriate. The distribution and ecology of F. atomus is discussed.

Qualitative and quantitative study of the planktonic and epiphytic diatoms in east hammer marsh southern Iraq

Thesis

Full-text available

Dec 2019

Sarah Sadiq Rasheed

Quantitative and qualitative study of the planktonic and epiphytic diatoms in east hammer marsh southern Iraq

Reconstruction of the geological history of the Lithuanian Maritime Region from MIS 6 to MIS 3

Article

Full-text available

Jun 2021
QUATERN INT

The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called Lithuanian Maritime Region (LMR) - a belt several tens of kilometres wide along the Baltic Sea coast - is characterised by a complicated Quaternary structure and many of unsolved problems related to stratigraphy and palaeogeography. The inter-till lacustrine sediments widespread in the middle part of the Pleistocene thickness play a key role in solving the mentioned problems. The primary inter-till sediments were attributed, as a single lithostratigraphic unit, to the late Saalian Glaciation (MIS 6, Pamarys Sub-Formation; according to the Lithuanian Quaternary Stratigraphic Scheme). Subsequent detailed investigations show that the investigated inter-till succession represents a more complicated sediment complex formed over a wide time interval from the Saalian ice sheet decay at the very end of MIS 6 to the beginning of severe climate cooling during MIS 4. This standpoint is confirmed by the results of a few series of OSL and IR-OSL datings of inter-till sediments, as well as by data of pollen and diatom analysis. The more detailed stratigraphic subdivision of the inter-till sedimentary complex offers a new significant insight into the regional stratigraphic scheme of the Quaternary. As a result of the mentioned investigations, a new original reconstruction of the palaeogeographic situation in the LMR during the MIS 6 - MIS 3 time span was carried out. The lowermost part of the investigated inter-till sediments, attributed to MIS 6, could be correlated with the third MIS 6 warming in Northern Eurasia about 155 ka ago. The reconstruction of the palaeoenvironmental changes starting from MIS 6 and lasting to MIS 3 shows that the Eemian Sea MIS 5e in age was absent in the LMR, while part of the south-eastern Baltic Sea region was covered by a continental ice sheet during MIS 4 and, possibly, the very beginning of MIS 3.

Diatom Record of Holocene Moisture Variability in the San Bernardino Mountains, California, USA

Chapter

Full-text available

Apr 2021

Lower Bear Lake, in the San Bernardino Mountains, contains a Holocene paleohydrology record for southern California. The diatom and sediment geochemistry record indicates that the region experienced a wet Early Holocene followed by a gradual decrease in precipitation, which was punctuated by four strong and five weak pluvial episodes. The Lower Bear Lake record is compared with that of Silver Lake, a Mojave River terminal lake with headwaters in the San Bernardino Mountains, which exhibited several pluvial events at roughly the same time. The comparison is extended to records in relative proximity to Bear Lake (Dry Lake, Lake Elsinore, and San Joaquin marsh) and to two lakes with headwaters in the Sierra Nevada (Tulare Lake and Owens Lake). All exhibit a wet Early and early Middle Holocene wet interval and gradual drying through the remainder of the Holocene but differ in the expression of the pluvial episodes observed at Lower Bear Lake. The pluvial episodes are likely the result of changes in the storm track that affects the frequency and magnitude of winter storms in the area. These episodes are controlled by complex oceanic and atmospheric interactions and may be the result of the synchronous interaction of several teleconnections.

Mastogloia jahniae sp. nov., a new diatom (Bacillariophyceae) from the Baltic Sea coast of Sweden

Article

Full-text available

Feb 2021

Described is here Mastogloia jahniae sp. nov. a species new to science from Skatan on the Baltic Sea, east coast of Sweden. Description of this new species is based on light and scanning electron microscopy. The new species is classified in the Mastogloia section Ellipticae and is characterized by having radiating short and long striae around the central area, sinuous raphe branches and partecta displaced toward the middle of the valve by a siliceous flange. M. jahniae sp. nov. in terms of size is rather small whereas in terms of ecology appears an epipelic brackish water species. The new species was rather rare in all samples collected from Skatan and has not been found in the other adjacent regions sampled. A comparison with similar established Mastogloia species is provided.

Ecotoxicological Studies on the Effect of Roundup® (Glyphosate Formulation) on Marine Benthic Microalgae

Article

Full-text available

Jan 2021
Int J Environ Res Publ Health

Glyphosate is a very effective herbicide and the main active ingredient in Roundup®—the most extensively used herbicide in the world. Since glyphosate is highly water soluble it reaches water bodies easily in surface water runoff. This prompted us to undertake an experiment to evaluate the effects of glyphosate in Roundup® on natural communities of marine microphytobenthos. Microphytobenthos communities were obtained from the environment, and after transporting them to the laboratory and acclimatizing them, they were tested under controlled conditions. Changes in microphytobenthos composition and structure and the deteriorating condition of the cells of community-forming organisms (assessed by analyzing changes in chloroplast shape) were used to assess the impact of Roundup® on endpoints. The tests indicated that microphytobenthic communities were relatively resistant to herbicide. The species richness of the communities probably enabled them to rebuild effectively. Sensitive species were replaced by those more tolerant of glyphosate. Only at the highest glyphosate concentration (8.5 g·dm −3) tested was a strong negative effect noted that limited community abundance and eliminated some of the organisms. The dominant diatoms in the communities were replaced by intensively developing cyanobacteria; which ultimately comprised nearly 60% of all the cells observed in the communities.

Diatoms in Estuaries and Tidal Marshes

Article

Full-text available

Oct 2007

Scott W. Starratt

Diatoms from estuarine and marsh sediments can be used to evaluate a number of geological processes. Information on salinity, elevation, and substrate derived from modern assemblages have been used to determine local and regional Holocene sea level history, identify seismic and tsunami events, and aid in the recognition of regional variations in precipitation. In order to apply diatoms to these questions, it is necessary to have a detailed knowledge of the ecology of marine, brackish, and freshwater taxa, as well as an understanding of the taphonomic processes that determine the final diatom assemblage. The potential for studies of pre-Holocene estuarine depositional systems is largely limited by the availability of study sites.

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Intercalibration and Distribution of Diatom Species in the Baltic Sea 5

Abstract

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