Stable oxygen and carbon isotope information on the establishment of a new, opportunistic foraminiferal fauna in a Swedish Skagerrak fjord basin, in 1979/1980

Significant faunal changes reported from recent, coastal environments, which are not directly influenced by urban and industrial impact, are rarely seen. In Gullmar Fjord on the Swedish west coast, a significant foraminiferal fauna change occurred in connection with severe low-oxygen conditions that evolved in the winter of 1979/1980. A foraminiferal fauna marked by common Skagerrak–Kattegat species, which had previously characterised the deep fjord basin, was replaced by the opportunistic, low-oxygen tolerant species Stainforthia fusiformis (Williamsson).To study this phenomenon further we performed stable oxygen and carbon isotope analyses on the indicator species itself, S. fusiformis, both on specimens from sediment cores representing approximately the last 85 years and on living (stained) individuals taken from a transect across the deep fjord basin. Our purpose was to detail how and why S. fusiformis, came to dominate the fauna.The oxygen isotope results suggest that salinities and temperatures in the deep basin have been relatively constant over the last c. 85 years, while the carbon isotopes show a significant change towards more negative values in association with the faunal shift of 1979/1980. The combined results from both the cores and the surface sediments suggest that S. fusiformis did not inhabit the deep basin until 1980. Before then, almost all specimens of S. fusiformis were small sized and their carbon isotope values suggest they were re-deposited shallow-water specimens that had been transported down to the central, deep basin as part of a suspension load. After a major faunal extinction in 1979–1980, S. fusiformis of all sizes suddenly appeared in large numbers and their carbon isotopic values were similar to the signal from registered in the recent, living fauna within the deep basin. This suggests that the opportunistic S. fusiformis established itself in the deep basin as a consequence of the severe low-oxygen event and the faunal crash of the previously dominating Skagerrak–Kattegat fauna.     

Benthic foraminiferal population fluctuations related to anoxia: Santa Barbara Basin

The pore-water geochemistry and benthic foraminiferal assemblages of sediments from two slope sites and within the central portion of the Santa Barbara Basin were characterized between February 1988 and July 1989. The highest foraminiferal numerical densities (1197 cm^–3 as determined by an ATP assay) occurred at a slope site in June 1988 (550 m) in partially laminated sediments. In continuously laminated sediments from the central basin, foraminifera were found living (as determined by ATP assay) in October 1988 to depths of 4 cm, and specimens prepared for transmission electron microscopy were found with intact organelles to 3 cm, indicating their inhabitation of anoxic pore waters. Ultrastructural data from Nonionella stella is consistent with the hypothesis that this species can survive by anaerobic respiration. However, the benthic foraminifera appear unable to survive prolonged anoxia. The benthic foraminiferal population was completely dead in July 1989 when bottom water O₂ was undetectable.     

Experimental and field evidence of Antarctic foraminiferal tolerance to anoxia and hydrogen sulfide

The common occurrence of foraminifera in strata deposited under anoxic environmental conditions throughout the geologic record raises the question of whether foraminifera actually survive anoxic or reducing conditions. To test this, benthic foraminifera from McMurdo Sound, Antarctica were exposed to anoxic or reducing conditions for 30 days. These Antarctic forms are known to be exposed to anoxic events in their natural environment. An adenosine triphosphate (ATP) assay was used to determine foraminiferal survival, and their ultrastructure was examined using transmission electron microscopy (TEM) to evaluate any possible effect that might have resulted from exposure to anoxic or reducing conditions. The experimental treatments did not have any statistically significant effects upon the foraminifers with regards to survival or average ATP content per individual including the four most common living species. Some ultrastructural evidence for encystment (fibrillar membrane-bound bodies in the cytoplasm of many specimens) was observed. Field data include the observation thatGlobocassidulina cf.G. biora resides in sediments to depths of 7 cm, as evidenced by ultrastructural investigations. A specimen ofGlobocassidulina cf.G. biora collected from sediments containing anoxic pore waters showed numerous bacteria within the confines of the organic lining. The occurrence of cytoplasmic inclusions similar in appearance to car☐ysomes within these bacteria suggest possible affinities to the chemolithotrophicThiobacillus. Bacteria of this type were not observed in specimens collected from oxygenated pore waters. These field and laboratory findings suggest that certain foraminifera may be facultative anaerobes able to withstand reducing conditions.     

Changes in k, rb, and na transport to shoots after anoxia

The effect of anoxia on subsequent uptake and transport of K, Rb, and Na was examined with seedlings of barley (Hordeum vulgare L.), corn (Zea mays L.), and tall fescue (Lolium × Festuca hybrid derivative) to further our understanding of xylem loading. Roots were incubated in solutions depleted of O₂ by flushing with N₂ gas. After 1 hour exposure, plants were returned to aerated solutions for 16 hours prior to measuring uptake and transport. For each species, anoxia pretreatment significantly enhanced Na transport to the shoot. The rate of Na accumulation into roots, however, was not affected. There was no enhancement of either K or Rb accumulation in shoots, indicating specificity for Na transport. A minimum exposure to anoxia of 30 minutes and a minimum of 12 hours elapsed time was necessary to achieve the maximum rate of Na transport to the shoot in barley seedlings. Accumulation of Na in the shoot of both the control and anoxia pretreated barley plants was inhibited by anoxia and by addition of the proline analog, l-azetidine-2-carboxylic acid, during the uptake period. Enhancement of Na transport was associated with a proportional increase in the rate of synthesis of a membrane bound protein with a molecular weight of 78,000 daltons.     

Living foraminifera and total populations in salt marsh peat cores: Kelsey Marsh (Clinton, CT) and the Great Marshes (Barnstable, MA)

Common species of intertidal agglutinated benthic foraminifera in salt marshes in Massachusetts and Connecticut live predominantly at the marsh surface and in the topmost sediment (0–2.5 cm), but a considerable part of the fauna lives at depths of 2.5–15 cm. Few specimens are alive at depths of 15–25 cm, with rare individuals alive between 25–50 cm in the sediments. Specimens living between the sediment surface and 25 cm deep occur in all marsh settings, whereas specimens living deeper than 25 cm are restricted to cores from the lower and middle marsh, and have an irregular distribution-with-depth. Lower and middle marsh areas are bioturbated by metazoa, suggesting that living specimens reach these depths at least in part by bioturbation. High-marsh sediments in New England consist of very dense mats of Spartina patents or Distichlis spicata roots and are not bioturbated by metazoa. In this marsh region bioturbation by plant roots and vertical fluid motion may play a role in moving the foraminifera into the sediment. The depth-distribution of living specimens varies with species: living specimens of Trochammina inflata consistently occur at the deepest levels. This suggests that species have differential rates of survival in the sediment, possibly because of differential adaptation to severe dysoxia to anoxia, or because of differing food preferences. There is no simple correlation between depth-in-core and faunal diversity, absolute abundance, and species composition of the assemblages. It is therefore possible to derive a signal of faunal changes and thus the environmental changes that may have caused them from the complex faunal signal of fossil assemblages.     

Pseudoidium javanicum,a new species of powdery mildew on Acalypha spp. from Indonesia

Pseudoidium javanicum is proposed as a new species based on analyses of 28S, ITS and IGS rDNA sequences, and morphological data. This new species was found on Acalypha wilkesiana var. marginata, A. argentea, and A. cristata collected from Cibodas Botanical Garden, Bogor (West Java Province, Indonesia). Our analyses showed that all these specimens have identical rDNA sequences and similar morphological characteristics. They form a distinct clade separated from other species of Erysiphaceae. Pseudoidium javanicum differs from Erysiphe acalyphae by having shorter conidiophores and foot cells 1–3 times as long as the 0–2 following cells. The conidial size of Ps. javanicum is also smaller than that of E. jatrophae.     

Metabolic depression is delayed and mitochondrial impairment averted during prolonged anoxia in the ghost shrimp, Lepidophthalmus louisianensis (Schmitt, 1935)

Lepidophthalmus louisianensis burrows deeply into oxygen-limited estuarine sediments and is subjected to extended anoxia at low tides. Large specimens (> 2 g) have a lethal time for 50% mortality (LT₅₀) of 64 h under anoxia at 25 °C. Small specimens (< 1 g) have a significantly higher LT₅₀ of 113 h, which is the longest ever reported for a crustacean. Whole body lactate levels rise dramatically under anoxia and exceed 120 μmol g.f.w.^− 1 by 72 h. ATP, ADP, and AMP do not change during 48 h of anoxia, but arginine phosphate declines by over 50%. Thus arginine phosphate may help stabilize the ATP pool. Surprisingly, when compared to the aerobic resting rate, ATP production under anoxia declines only moderately during the first 12 h, and drops to only about 30% between 12 and 48 h. Finally, after 48 h of anoxia, a major metabolic depression to less than 5% occurs. Downregulation of metabolism is delayed in L. louisianensis compared to many invertebrates that exhibit facultative anaerobiosis. Bioenergetic constraints as a result of eventual metabolic depression lead to ionic disturbances like calcium overload and compromised membrane potential of mitochondria. Because these phenomena trigger apoptosis in mammalian species, we evaluated the susceptibility of ghost shrimp mitochondria to opening of the mitochondrial permeability transition pore (MPTP) and associated damage. Energized mitochondria isolated from hepatopancreas possess a pronounced capacity for calcium uptake. Exogenous calcium does not stimulate opening of the MPTP, which potentially could reduce cell death during prolonged anoxia.     

Mitochondrial Ultrastructure of Three Hygrophyte Species at Anoxia and in Anoxic Glucose-Supplemented Medium

Mitochondrial ultrastructure of excised roots of Alisma plantago-aqisaticaL., Lycopus europaeus L and Glyceria fluitans L. were electron-microscopicallystudied at anoxia and in anoxic glucose- supplemented mediumin order to find Out if the roots of the three hygrophytes growingon water-logged anaerobic soils have an increased resistanceto anoxia. Irreversible destruction of mitochondrial membranes and othersubcellular structures was shown to occur in the above plants'roots after 24 h at anoxia or in anoxic glucose-supplementedmedium. Only in roots of Glyceria had exogenous glucose a protectiveaction, yet in this case, too, a 48 h anacrobic exposure resultedin a deep-going degradation of cell ultrastructure. It is concluded that though the plants in question grow on soilsdevoid of O₂ their roots avoid anaerobiosis through translocationof O₂ from aerated parts, which appears to explain why theseplants have not developed a biochemical mechanism of adaptationto anaerobiosis in the process of evolution. Key words: Anaerobiosis, hygrophytes, mitochondrial ultrastructure     

Current Status of Immunofluorescence Techniques for Rapid Detection of Shigellae in Fecal Specimens

Polyvalent Shigella conjugates were prepared for Shigella groups A, B, C, and D. After preliminary testing with pure cultures of both homologous and heterologous organisms, these reagents were used in three evaluation studies. Fecal specimens from patients hospitalized with diarrhea, from children involved in an institutional outbreak of dysentery due to S. sonnei, and from patients with diarrhea in Arizona were screened by fluorescent-antibody (FA) tests and were cultured. Specimens were examined at various periods of time after collection and after incubation in broth and saline. Results showed that shigellae were detected most frequently when specimens were cultured immediately after collection. FA tests revealed more positive results when the specimens were incubated in either saline or broth than when they were examined immediately after collection. The S. sonnei conjugate gave the most reliable results of any of the Shigella FA reagents used in these investigations. It proved to be both sensitive and specific.     

Novel Clade of Rickettsia spp. from Leeches

Intracellular rickettsia-like structures were found in the tissues of a glossiphoniid leech, Torix tagoi, by transmission electron microscopy. Diagnostic PCR analysis using specific primers suggested that of the nine glossiphoniid species examined, two species, T. tagoi and Hemicrepsis marginata, harbored bacteria of the genus Rickettsia. A 1.5-kb eubacterial 16S rRNA gene segment obtained from each of these species was amplified by PCR, cloned, and sequenced. Phylogenetic analysis of the 16S rRNA gene demonstrated that the Rickettsia species found in the leeches constituted a novel clade that is distinct from the clade of arthropod-associated Rickettsia species. In natural populations, 97.7% (43 of 44) of T. tagoi leeches and 100% (9 of 9) of H. marginata leeches carried Rickettsia, suggesting that infection with Rickettsia is prevalent in these leeches. This is the first report of Rickettsia found in annelids.

     

Phylogenetic placement of Cibicidoides wuellerstorfi (Schwager, 1866) from methane seeps and non‐seep habitats on the Pacific margin

Benthic foraminifera are among the most abundant groups found in deep‐sea habitats, including methane seep environments. Unlike many groups, no endemic foraminiferal species have been reported from methane seeps, and to our knowledge, genetic data are currently sparse for Pacific deep‐sea foraminifera. In an effort to understand the relationships between seep and non‐seep populations of the deep‐sea foraminifera Cibicidoides wuellerstorfi, a common paleo‐indicator species, specimens from methane seeps in the Pacific were analyzed and compared to one another for genetic similarities of small subunit rDNA (SSU rDNA) sequences. Pacific Ocean C. wuellerstorfi were also compared to those collected from other localities around the world (based on 18S gene available on Genbank, e.g., Schweizer et al., 2009). Results from this study revealed that C. wuellerstorfi living in seeps near Costa Rica and Hydrate Ridge are genetically similar to one another at the species level. Individuals collected from the same location that display opposite coiling directions (dextral and sinstral) had no species level genetic differences. Comparisons of specimens with genetic information available from Genbank (SSU rDNA) showed that Pacific individuals, collected for this study, are genetically similar to those previously analyzed from the North Atlantic and Antarctic. These observations provide strong evidence for the true cosmopolitan nature of C. wuellerstorfi and highlight the importance of understanding how these microscopic organisms are able to maintain sufficient genetic exchange to remain within the same species between seep and non‐seep habitats and over global distances.     

Biogeographic distribution of rudists and benthic foraminifera: An approach to Campanian-Maastrichtian palaeobiogeography of Turkey

Transgressive sequences of Campanian-Maastrichtian Stages in Turkey generally begin with medium- to coarse-grained clastics and continue with shallow marine limestones, reefal limestones and then open marine rhythmic fine-grained clastics. These mixed siliciclastic-carbonate sequences are observed on three main platforms known as Rhodope-Pontide (RPP), Anatolide-Tauride (ATP) and Arabian (AP). New species of the rudist genera Gorjanovicia, Radiolites, Sauvagesia, Durania and Sabinia are observed on the RPP. Yvaniella and Ugarella are only found on this platform. Orbitoides gruenbachensis Papp is the most abundant species of benthic foraminifera on the RPP. Cideina soezerii (Sirel), Dizerina anatolica Meriç, Helicorbitoides boluensis Sirel, Ilgazina unilateralis Erdo?an, Nummofallotia kastamonica Özgen-Erdem, Selimina spinalis ?nan, Sirelina orduensis Meriç and ?nan, Smoutina cruysi Drooger are also observed on this platform. Rudist and benthic foraminifera on the ATP have both high diversity and abundance in comparison with RPP and AP faunas. Genus and species diversity of the rudist fauna is quite high: 17 genera and 36 species are described. New rudist genera such as Darendeella, Kurtinia and Balabania and many new species of Radiolitidae and Hippuritidae may be restricted to this platform. Characteristic larger benthic foraminifera contain 18 genera and 37 species. Among benthic foraminifera Loftusia ketini Meriç, L. turcica Meriç and Av?ar, Postomphalocyclus merici ?nan and Pseudoedomia hekimhanensis Görmü? are also likely restricted to this platform. Rudist diversity on the AP is poor. Four endemic genera (Vautrinia, Dictyoptychus, Paracaprinula and Hatayia) and two species (Hippurites syriaca Vautrin, Pironaea syriaca Vautrin) characterize the fauna on this platform. Loftusia diversity and abundance among the benthic foraminifera is quite high. Arnaudella grossouvreii Douvillé, Discyclina schlumbergeri Munier-Chalmas, Loftusia harrisoni Cox, L. elongata Cox, L. matsumaruii Meriç and Görmü? and Pseudorbitolina marthae Douvillé are only documented from southeastern Anatolia. Biogeographic distributions of rudist and benthic foraminifera show different faunal associations on the three main platforms (RPP, ATP and AP). Our data from both rudist and benthic foraminifera indicate that different faunal associations and existence of restricted genera and species may be associated with a deep marine barrier to circulation during the Campanian-Maastrichtian. Southern and northern branches of the Neotethyan Ocean are considered to be barriers in preventing migration of the species.     

Near anoxia and sulfide as possible factors influencing the spatial distribution of Acartia tonsa and Acartia clausi: Comparative evaluation of egg tolerance

In many coastal and estuarine areas the planktonic copepods Acartia tonsa and Acartia clausi show a spatial separation with A. tonsa restricted to brackish waters and confined environments and A. clausi inhabiting areas more influenced by sea water. The hatching and viability of A. tonsa and A. clausi eggs exposed to anoxia and anoxia/sulfide (conditions that are frequent in bottom waters of the most confined areas) was evaluated to determine if these stress factors play a role in the distribution of these species. Subitaneous eggs, spawned by laboratory reared organisms, were incubated in near anoxia (< 7.59 × 10^− 3 mmol O₂ L^− 1) or anoxia/sulfide (∼ 1 mmol L^− 1) for different periods (1, 4, 8 and 15 days), then transferred to normoxic conditions. The exposure of the eggs to near anoxia and sulfide appears to induce the same response (quiescence) in both species. Exposure times ≤ 8 days to near anoxia or anoxia/sulfide did not affect egg viability, while 15 day exposure caused significant declines in hatching success of both species. A significant difference between the effects of near anoxia and anoxia/sulfide was observed when incubation lasted 15 days; hatching of eggs exposed to sulfide being higher than that of eggs exposed to near anoxia for both species. No significant differences were observed between the two species in hatching success of eggs exposed to both near anoxia and anoxia/sulfide (with the exception of eggs incubated in near anoxia for 4 days). The results indicate that the impact of anoxia and sulfide on the eggs of the two Acartia species cannot be a factor explaining the spatial distribution in coastal and brackish environments of these copepods.Feeding experiments on A. clausi were also performed. Suitability of different algal species to rear this copepod was evaluated and the results were compared with data previously obtained for A. tonsa. Differences in feeding needs between A. clausi and A. tonsa are discussed.     

Molecular characterization of the non-costate morphotypes of buliminid foraminifers based on internal transcribed region of ribosomal DNA (ITS rDNA) sequence data

We performed molecular phylogenetic analyses of four morphotypes of the benthic foraminiferal genus Bulimina (B. aculeata, B. marginata f. marginata, B. marginata f. denudata, and B. elongata) based on sequences of internal transcribed spacer region of ribosomal DNA (ITS rDNA). Six genetically distinct phylotypes were revealed by our phylogenetic analyses. The six phylotypes basically correspond to the fundamental morphotypes: clades A + B (B. aculeata); clade C (B. elongata); clade D (B. marginata f. denudata); clade E (B. marginata f. marginata genotype 1); and clade F (B. marginata f. marginata genotype 2). All six phylotypes are well distinguished, except phylotype B, which shows only little sequence divergence compared to clade A, possibly indicating that genetic differentiation is in progress. Morphological characters including the direction, placement, and shape of spines, the angle of undercutting of chamber periphery, and the roundness of the chambers were stable among specimens of each clade. In contrast, the length and density of spines, and chamber size, were variable within each clade. These intermediate morphological characters may reflect ecophenotypic variation. Our study clearly shows that the examined B. acuelata, elongata, and denudata morphospecies are genetically separated and that B. marginata is a species complex comprising several genotypes. A novel phylotype represent different morphotype compare to B. marginata f. marginata that can be distinguished based on differences of chamber angularity, the direction, placement, and shape of spines, and test dimensions.     

Taxonomic composition and distribution of soft-walled monothalamid foraminifera in the area of Zernov’s Phyllophora Field (NW Black Sea)

We studied assemblages of soft-walled, single-chambered foraminifera (monothalamids) at eight stations in the area of Zernov's Phyllophora Field (ZPF) on the NW continental shelf of the Black Sea. This work is based on samples collected during Cruise 70 of the RV Professor Vodyanitsky and provides the first analysis of the taxonomic composition of monothalamids from this region. These delicate, poorly known foraminifera were found at all stations in the studied area. They were represented by nine forms that are identified to species or genus level as well as 14 undescribed species, nine of which are found in the Black Sea for the first time. Four species, Psammophaga sp., Vellaria pellucida, Goodayia rostellata and Krymia fusiformis, were most abundant, with Psammophaga sp. being the dominant species overall. Previous studies have suggested a link between members of this genus and eutrophication. There are a number of taxonomic parallels between these ZPF assemblages and those from the Adriatic Sea, e.g. the occurrence of the genera Goodayia, Psammophaga and Vellaria, although it is possible that some other taxa are endemic to the Black Sea.     

Chemotaxonomic and ecological implications of anthocyanins in Elythranthera

Elythranthera emarginata (Lindl.) A. S. George and E. brunonis (Endl.) A. S. George both contain cyanidin-3,5-diglucoside and delphinidin-3,5-diglucoside. Pigment concentrations in E. marginata are 2 · 5 times those of E. brunonis. Cyanidin/delphinidin ratios in both species are essentially the same. These findings are discussed in relation to the taxonomy, color, and the life cycle of Elythranthera.     

Sulfide and cyanide induced mortality and anaerobic metabolism in the arcid blood clam Scapharca inaequiv alvis

1. The survival and metabolic adjustments of the blood clam S. inaequivalvis have been determined at environmental anoxia and tissue anoxia induced by sulfide and cyanide.2. Times to 50% mortality were established in clams placed in oxygenated seawater with and without dissolved sulfide or free cyanide or deoxygenated seawater with and without dissolved sulfide.3. Anaerobic metabolism was studied in live animals and in red blood cells incubated in vitro. Tissue anoxia due to sulfide and cyanide caused greater changes in the levels of aspartate and the pyruvate derivatives, compared to environmental anoxia.     

Carbon Transport and Root Respiration of Split Root Systems of Phaseolus vulgaris Subjected to Short Term Localized Anoxia

The influence of anoxia on carbon transport and root respiration was evaluated by applying [U-¹⁴C]sucrose to the foliage. Translocation patterns to the root systems of two dry edible bean genotypes (Phaseolus vulgaris L.) were examined after a 3-day exposure to aerated and nonaerated environments. Localized anoxia of root systems was simulated by growing roots in split configurations and exposing half of the system to anoxic conditions. Anoxia of the root system for 72 hours reduced the movement of ¹⁴C label into the roots with concurrent accumulations in the hypocotyl region. The translocation of ¹⁴C label to anoxic roots was less than 50% of the aerated controls of both genotypes. Most of the ¹⁴C label translocated to anoxic root systems was excluded from respiratory metabolism during the 3-hour pulse/chase period and was an order of magnitude less than the aerated controls. These observations suggest that the bulk of ¹⁴C label which entered the root during the anoxic period was unavailable for metabolism by the enzymes of glycolysis and/or was diluted by a relatively large metabolite pool. A higher percentage of ¹⁴C label was translocated to the aerated half of the localized anoxia treatment relative to the half of the aerated controls. The proportion of ¹⁴C label translocated to the root system in the aerated control was 20 and 16% compared to 28 and 25% in the aerated localized anoxia treatment for the genotypes Seafarer and line 31908, respectively. Line 31908 partitioned a greater percentage of ¹⁴C-labeled compounds to the actively growing fraction of the root system in the localized anoxia treatment than did Seafarer. This suggests a greater reliance on previously stored carbohydrate for immediate root growth in Seafarer than in line 31908.