Accumulation of lead, cadmium, manganese, copper and zinc by sludge worms; Tubifex tubifex in sewage sludge

Tubifex tubifex has been shown to survive in organic polluted environments, however, not much has been done on its inorganic pollution tolerance. Samples of T. tubifex and their respective sewage sludge were taken from Soche wastewater treatment plant in Blantyre City, Malawi during July 2007 to November 2008. The total number of sludge samples taken was fifty one which was made into seventeen composite samples. A total of seventeen T. Tubifex samples were also collected. The samples were analyzed for copper, lead, manganese, zinc and cadmium using standard methods from American Public Health Association and Association of Official Analytical Chemists. The concentrations of metals in sewage sludge and T. tubifex were on dry weight basis and the metals determined were acid extractable. In general, heavy metals concentration was lower in T. tubifex than in sewage sludge. The range of heavy metals concentrations were (in sludge and (T. tubifex)): zinc 275.3–361.5 mg/kg (45.0–82.2 mg/kg), manganese 293.7–230.1 mg/kg (1.21–3.69 mg/kg), copper 86.5–120.1 mg/kg (1.6–4.7 mg/kg), lead 11.2–22.4 mg/kg (Below detection limit–0.95 ) and cadmium 1.12–2.31 mg/kg (1.08–2.18 mg/kg). The results showed significant differences between the concentrations of manganese, copper, lead and zinc in sewage sludge and T. tubifex (p < 0.05). However there was no significant difference between the concentrations of cadmium in sewage sludge and T. tubifex (p > 0.05). T. tubifex did not show the ability to accumulate heavy metals (attributed to its high defecation and metabolic rate) except for cadmium hence cannot be used as a bioindicator for heavy metal pollution in sludge.     

A new approach to the Late Miocene-Early Pliocene forms of the genus Apocricetus. Apocricetus alberti (Rodentia,Mammalia) from Venta del Moro (Cabriel Basin,Spain)

The species of the genus Apocricetus are considered to form the phyletic lineage A. aff. plinii (MN11)–A. plinii–A. alberti–A. barrierei–A. angustidens (MN16). Along this lineage, gradual morphological and biometrical changes occur, but not all the species are represented by rich populations. The assemblage of Apocricetus alberti from Venta del Moro is by far the most abundant collection of this species. This population shows a great morphological variability in some characters like the morphology of the anteroconid and the anterolophulids in m1 and the shape of the anterolophule in M1, with morphotypes that resemble both older and younger populations of Apocricetus. Along the phyletic lineage of Apocricetus, a change in the shape of m3 occurs, from predominantly subtriangular forms in the oldest populations to predominantly subrectangular in the youngest. To quantify this feature we use the posterior width of the molar and the anterior width/posterior width ratio, proposing five morphological categories, from extremely triangular to subrectangular.     

Genetical Processes of Evolution on High Oceanic Islands

The Hawaiian Drosophila project has been in progress for 20 years. Recently, emphasis has been placed on studies of genetic variability in natural populations. The data generated are of extraordinary interest for understanding the genetic basis of evolution. The findings are relevant not only to islands forms but also to species in continental ecosystems. Chromosomal, electrophoretic and morphometric studies of specimens from local populations (demes) of island species have shown them generally to be as rich in genetic variability as demes of widespread continental species. The main difference between continntal and insular species is that the latter have smaller total population sizes insular species have fewer demes. On high volcanic islands, the most striking mode of speciation is through one or a few inter-island or inter-volcano founders. The case of Drosophila silvestris from the island of Hawaii is presented. Enforced isolation appears to foster genetic divergence. An unexpected results is that the founder effect does not drasticaly reduce genetic variablity. Rather, it appears to induce a shift in the polygenic heterozygous balances that underlie the genetics of quantitative characters, especially those dealing with mating behavior.In view of these findings, the well-known exuberance of novel adaptations and species observed on isolated oceanic islands is understandable.     

New remains of Eremotherium laurillardi (Lund, 1842) (Megatheriidae,Xenarthra) from the coastal region of Ecuador

New remains of Eremotherium were recovered from the Pacific coast of Ecuador’s Manabi province. The Machalilla fossiliferous locality records the northernmost presence of Eremotherium along the Pacific coast of South America. Most of the fossil remains belong to the same individual, mainly its posterior half, but other individuals are represented. Among the better-preserved specimens are skull fragments, most of the hind limb bones and a number of trunk and caudal centra. These remains were compared with samples collected during the 20th century along the southern coastal regions of Ecuador and northern Peru. Many characters of the long bones and tarsals testify to a possibly different lineage despite the closeness of other Eremotherium populations. Some metric and morphological aspects suggest a different space-temporal southern Caribbean provenance. Other Eremotherium specimens, coming from other Ecuadorian localities, were studied and compared with classic Eremotherium samples. Interesting morpho-functional aspects are pointed out with regard to the tail and its importance in the bipedal stance.     

Genetic diversity and structure of natural and transplanted eelgrass populations in the Chesapeake and Chincoteague Bays

The objective of this study was to gain baseline population data on the genetic diversity and differentiation of eelgrass (Zostera marïna L.) populations in the Chesapeake and Chincoteague bays. Natural and transplanted eelgrass beds were compared using starch gel electrophoresis of allozymes. Transplanted eelgrass beds were not reduced in genetic diversity compared with natural beds. Inbreeding coefficients (F_IS) indicated that transplanted eelgrass beds had theoretically higher levels of outcrossing than natural beds, suggesting the significance of use of seeds as donor material and of seedling recruitment following transplantation diebacks. Natural populations exhibited very great genetic structure (F_ST=0.335), but transplanted beds were genetically similar to the donor bed and each other. Genetic diversity was lowest in Chincoteague Bay, reflecting recent restoration history since the 1930s wasting disease and geographical isolation from other east coast populations. These data provide a basis for developing a management plan for conserving eelgrass genetic diversity in the Chesapeake Bay and for guiding estuary-wide restoration efforts. It will be important to recognize that the natural genetic diversity of eelgrass in the estuary is distributed among various populations and is not well represented by single populations.     

Cytological and Population Genetic Changes in Northwestern Iberian Mussels After the Prestige Oil Spill

The ecological catastrophe produced by the Prestige oil spill (November 2002) caused severe damage in both North Spanish and French coastal communities. Wild mussel populations of Mytilus galloprovincialis in a zone with marginal introgression of Mytilus edulis were affected at all levels, from high DNA damage to increased polycyclic aromatic hydrocarbon content in tissues. In this article, we describe cytological and population genetic changes of wild mussel populations from the northwestern Iberian coast following the catastrophe. The micronucleus test was employed as an indicator of cytological damage, and the Barcoding mitochondrial cytochrome oxidase I (COI) and the nuclear Glu-5′ genes were analyzed for determining the species and assessing population genetic diversity. Immediate increase of micronuclei counts after the oil spill was found, with a further decrease in consecutive months although the counts did not recover pre-Prestige levels. Reduced variation at mitochondrial sequences in the most exposed areas and reduction of M. edulis traces in the regional genetic pool also suggest long-term impact that may result in evolutionary changes. These results highlight the need of adopting more strict measures in order to prevent this type of accidents and avoid long-term effects on wild populations.     

Genetic differentiation and speciation in the estuarine isopodsCyathura polita andCyathura burbancki

We investigated the electrophoretically detectable variation at nine protein loci in seven populations ofCyathura polita and one population of the closely relatedC. burbancki from the Atlantic coast of North America. The average proportion of the genome heterozygous per individual \((\bar H)\) inC. polita ranges from about 0% in New Brunswick and Massachusetts to 9.3% in a Georgia population. \(\bar H\) in the population ofC. burbancki was 2.6%. On the basis of our results,C. polita can be separated into two geographic forms,northern (New Brunswick, Massachusetts, and Maryland) andsouthern (Georgia and Florida). The genetic distances between the southern and northernC. polita are similar to the genetic distances reported between species of several other invertebrate groups. Our genetic data support the idea that the northern and southern forms ofC. polita andC. burbancki comprise a triad of species that diverged from each other 2–3 million years ago. Since we know nothing about the genetic structure of populations ofCyathura between Georgia and Maryland, this interpretation must be considered preliminary.     

Seasonal phytoplankton composition in the lower Chesapeake Bay and old plantation Creek,Cape Charles,Virginia

During a 14-month phytoplankton study in the lower Chesapeake Bay, there was a bi-modal pattern of population peaks with fall and spring maxima. The phytoplankton was dominated bySkeletonema costatum and other diatoms similar to major dominants found on the continental shelf. The composition in an inlet adjacent to the Bay was similar throughout most of the period, but differed from Bay populations during the summer months when larger concentrations and diversity of phytoflagellates and small sized diatoms occurred. Seasonal phytoplankton assemblages characteristic for the lower and entire Chesapeake Bay are given with the seasonal appearances noted for 219 phytoplankters. The importance of nanophytoplankters, both diatoms and the phytoflagellates, to the total phytoplankton composition is also emphasized.     

The Late Pleistocene distribution of vicuñas (Vicugna vicugna) and the “extinction” of the gracile llama (“Lama gracilis”): New molecular data

We present the results of a palaeogenetic analysis of two Late Pleistocene camelids originating in southern Chile. Our analysis of two mitochondrial DNA fragments (control region and cytochrome b gene) reveals that these specimens do not belong to an extinct taxon, but rather to extant vicuña (Vicugna vicugna), whose modern distribution is restricted to the extreme elevations of the Andes, more than 3500 km to the north of where these specimens originated. Our results also suggest fossil specimens from Patagonia that are currently assigned to the extinct taxon Lama gracilis, may actually belong to V. vicugna, implying a continuous distribution of the latter from the southern tip of South America to the Andes during the Final Pleistocene. The haplotypes of both specimens are not present in modern populations, suggesting a loss of genetic diversity concomitant with the contraction of the vicuña geographical distribution during the Final Pleistocene or early Holocene.     

How Population Decline Can Impact Genetic Diversity: a Case Study of Eelgrass (<Emphasis Type="Italic">Zostera marina</Emphasis>) in Morro Bay,California

Seagrass populations are in decline worldwide. Eelgrass (Zostera marina L.), one of California’s native seagrasses, is no exception to this trend. In the last 8 years, the estuary in Morro Bay, California, has lost 95% of its eelgrass. Population bottlenecks like this one often result in severe reductions in genetic diversity; however, this is not always the case. The decline of eelgrass in Morro Bay provides an opportunity to better understand the effects of population decline on population genetics. Furthermore, the failure of recent restoration efforts necessitates a better understanding of the genetic underpinnings of the population. Previous research on eelgrass in California has demonstrated a link between population genetic diversity and eelgrass bed health, ecosystem functioning, and resilience to disturbance and extreme climatic events. The genetic diversity and population structure of Morro Bay eelgrass have not been assessed until this study. We also compare Morro Bay eelgrass to Bodega Bay eelgrass in Northern California. We conducted fragment length analysis of nine microsatellite loci on 133 Morro Bay samples, and 20 Bodega Bay samples. We found no population differentiation between the remaining beds in Morro Bay and no difference among samples growing at different tidal depths. Comparisons with Bodega Bay revealed that Morro Bay eelgrass contains three first-generation migrants from the north, but Morro Bay remains considerably genetically differentiated from Bodega Bay. Despite the precipitous loss of eelgrass in Morro Bay between 2008 and 2017, genetic diversity remains relatively high and comparable to other populations on the west coast.     

Allometry in the pliocene bivalveAstarte omalii: A new look at an old data set

The relationships between ontogeny and phylogeny have been studied for the bivalve Astarte omaliifrom the Lower, Middle, and Upper Pliocene of Belgium using canonical variates analysis, principal components in the form of multivariate allometry, and bivariate power functions or allometric equations. The results indicate that the three samples represent segments of a single evolutionary lineage which is characterized mainly by paedomorphosis where adult descendants are similar to juvenile ancestors. Recapitulation or peramorphosis is only observed for a single parameter. The Lower and Middle Pliocene samples are considered as Astarte omalii omalii,whereas the Upper Pliocene specimens are placed in A. omalii basteroti.The evolutionary trends most likely reflect changes in the living positions of the bivalves.     

Sulfur isotope study of a modern intertidal environment,and the interpretation of ancient sulfides

Extensive sulfur isotope distribution data for sulfides precipitated in an intertidal environment show no distinctive features when compared with isotope values for other marine, sedimentary sulfides. The fractionation ranges from α = 1.030 to α = 1.048. The pattern is characteristic for a system essentially open to sulfate, and isotope analyses of interstitial sulfates are corroborative. A population of sulfate-reducing bacteria of the order of 10⁹ organisms per cc of interstitial water is indicated. Seasonal variation of the isotope distribution reflects a transient sulfide composition and a bacterial population in which the fractionation effect is indirectly controlled by temperature. The data presented for this modern shallow water environment are at variance with an earlier assessment of isotopic distributions in ancient sulfides which linked shallow water environments with limited fractionation (α ? 1.025) in a closed system.     

Diurnal and Tidal Variability in the Photobiology of the Seagrass Halophila johnsonii in a Riverine Versus Marine Habitat

The threatened seagrass Halophila johnsonii grows intertidally to 3 m deep in river-influenced and marine-influenced habitats. In this study, environmental parameters and photosynthetic characteristics of H. johnsonii were measured hourly for populations from adjacent riverine and marine habitats under opposite tidal regimes (high tide at midday, low tide at midday). The two populations exhibited habitat-specific diurnal responses, which indicate long-term acclimatization to their different environments. During periods with similar bottom irradiances, effective photochemical efficiencies and chlorophyll concentrations were comparatively greater in the riverine population, indicative of low-light acclimation. In addition, ultraviolet pigment absorbance (340–345 nm) was generally greater in the riverine plants and it generally increased following ebb tides and decreasing salinity, suggesting a stress response. Multivariate analyses indicated that photosynthetic characteristics were most dissimilar when environmental conditions were most dissimilar, i.e., riverine plants when low tide occurred at midday compared to marine plants when high tide occurred at midday. Salinity, photosynthetically active radiation, and optical water quality (K _0PAR, S _CDOM, and a ₄₁₂) were most correlated with variability in photosynthetic characteristics. As there is no significant genetic variation among populations of H. johnsonii, the photosynthetic characteristics of the riverine and marine populations we examined reflect acclimation to their respective habitats through a highly phenoplastic physiology.     

Biomineralization of As(V)-hydrous ferric oxyhydroxide in microbial mats of an acid-sulfate-chloride geothermal spring, Yellowstone National Park

Acid-sulfate-chloride (pH∼3) geothermal springs in Yellowstone National Park (YNP) often contain Fe(II), As(III), and S(-II) at discharge, providing several electron donors for chemolithotrophic metabolism. The microbial populations inhabiting these environments are inextricably linked with geochemical processes controlling the behavior of As and Fe. Consequently, the objectives of the current study were to (i) characterize Fe-rich microbial mats of an ASC thermal spring, (ii) evaluate the composition and structure of As-rich hydrous ferric oxides (HFO) associated with these mats, and (iii) identify microorganisms that are potentially responsible for mat formation via the oxidation of Fe(II) and or As(III). Aqueous and solid phase mat samples obtained from a spring in Norris Basin, YNP (YNP Thermal Inventory NHSP35) were analyzed using a complement of chemical, microscopic and spectroscopic techniques. In addition, molecular analysis (16S rDNA) was used to identify potentially dominant microbial populations within different mat locations. The biomineralization of As-rich HFO occurs in the presence of nearly equimolar aqueous As(III) and As(V) (∼12 μM), and ∼ 48 μM Fe(II), forming sheaths external to microbial cell walls. These solid phases were found to be poorly ordered nanocrystalline HFO containing mole ratios of As(V):Fe(III) of 0.62 ± 0.02. The bonding environment of As(V) and Fe(III) is consistent with adsorption of arsenate on edge and corner positions of Fe(III)-OH octahedra. Numerous archaeal and bacterial sequences were identified (with no closely related cultured relatives), along with several 16S sequences that are closely related to Acidimicrobium, Thiomonas, Metallosphaera and Marinithermus isolates. Several of these cultured relatives have been implicated in Fe(II) and or As(III) oxidation in other low pH, high Fe, and high As environments (e.g. acid-mine drainage). The unique composition and morphologies of the biomineralized phases may be useful as modern-day analogs for identifying microbial life in past Fe-As rich environments.     

Frullania pinnata spec. nov. (Frullaniaceae,Porellales), a new leafy liverwort in mid-Cretaceous Burmese amber from Myanmar

An inclusion in Cretaceous amber from Myanmar is described as a new fossil species in the extant liverwort genus Frullania. The name Frullania pinnata is proposed for the taxon that is characterized by entire underleaves paired with a conspicuous pinnate branching pattern, two distinctive and stable morphological features. Entire underleaves are known in several extant Frullania species but had not previously been documented in Frullania in amber. The combination of morphological characters in this new fossil species is unknown in any crown group lineage of Frullania, and may very well represent a stem lineage element of the genus. This discovery is important because it expands our understanding of the diversity of Frullaniaceae in the Burmese amber forest as well as important ramifications for the phylogenetic reconstruction of extant Frullania lineages.     

Effects of menhaden predation of plankton populations in Narragansett Bay, Rhode Island

The Atlantic menhaden,Brevoortia tyrannus, is an abundant plankton-feeding fish that undertakes extensive seasonal migrations, moving from overwintering locations offshore south of Cape Hatteras to the mid-Atlantic Bight and New England inshore waters during spring and summer. A bioenergetic model, based on field and laboratory studies, shows that when large numbers of menhaden enter Narragansett Bay, Rhode Island, during spring and early summer, they significantly influence plankton populations through size-selective grazing and nutrient regeneration. A population biomass of 9.1×10⁶ kg of menhaden feeding for 12 h each day in the upper bay would result, in a substantial reduction of the instantaneous growth rate of the >20-μm phytoplankton. Instantaneous growth rates of zooplankton would be negative if the same population of menhaden was present, resulting in a reduction in the biomass of zooplankton. Given the ambient phytoplankton and zooplankton populations, menhaden could achieve the seasonal growth measured in Narragansett Bay during 1976 by feeding on average about 5 h d^?1. Daily nitrogen excretion rates of the 9.1×10⁶ kg menhaden population were 56.4% of the mean standing stock of ammonia-N in the upper bay. Because menhaden travel in schools their effects are likely to be intense but strongly localized, increasing spatial heterogeneity in the ecosystem. When the fish migrate southward in the fall they transfer between 3.3% and 6.2% of the nitrogen exported annually from the bay.     

Genetic transition between northern and southern populations of the estuarine isopod,Cyathura polita,and the discovery of a new species ofCyathura

Previous work on the genetics ofCyathura polita populations along the Atlantic coast indicated that northern and southern populations have diverged significantly. We used starch gel electrophoresis to study the transition between northern and southern populations for gene frequencies at four enzyme loci.Cyathura from three sites in the Carolinas were compared with those from representative populations in the north (Massachusetts) and south (Florida).Cyathura polita from the northern and southern populations were fixed for different alleles at three of the four loci assayed.C. polita from a population in North Carolina had the northern electromorph for two loci and were polymorphic at theEst locus for the northern and southern electromorphs, whileC. polita from a population in South Carolina had the southern electromorphs for two loci and were polymorphic at theMdh-1 locus for northern and southern electromorphs. Thus, there appears to be gene flow between the genetically differentiated populations in the north and south. One population ofCyathura from North Carolina had unique electromorphs at the four loci assayed and appears to be a new species.     

Stock Origins of Subadult and Adult Atlantic Sturgeon, Acipenser oxyrinchus, in a Non-natal Estuary, Long Island Sound

The anadromous acipenserid Atlantic sturgeon Acipenser oxyrinchus was listed in 2012 under the U.S. Endangered Species Act as having four endangered and one threatened distinct population segment (DPS) in American waters. Anthropogenic activities outside of natal estuaries, particularly bycatch, may hinder the abilities of some populations to rebuild. Most Atlantic sturgeon are residential for their first 2–6 years within their natal estuaries, whereas older subadults and adults may migrate to non-natal estuaries and coastal locations. Previous studies demonstrated that subadults and adults aggregate during summer at locations in Long Island Sound (LIS) and its tributary, the Connecticut River; however, the population origin of these fish is unknown. Because of its geographic proximity and relatively robust population, we hypothesized that the LIS and Connecticut River aggregations were almost solely derived from the Hudson River. We used microsatellite nuclear DNA analysis at 11 loci and mitochondrial DNA control region sequence analyses to estimate the relative contributions of nine Atlantic sturgeon populations and the five DPS to these aggregations using individual-based assignment tests and mixed-stock analysis. From 64 to 73 % of specimens from LIS were estimated to be of Hudson origin. Similarly, 66–76 % of specimens from the Connecticut River were of Hudson origin. However, moderate numbers of specimens were detected from distant spawning populations in the southeastern DPS and from two populations once thought to be extirpated or nearly so, the James River (6–7.3 %), and the Delaware River (7.6–12 %). Additionally, specimens were detected from all five DPS in both the LIS and Connecticut River collections. These results highlight the difficulty of evaluating the status of individual Atlantic sturgeon populations because of the propensity of subadults and adults to migrate for extended duration to distant sites where they may be vulnerable to anthropogenic disturbances.     

Evaluation of Genetic Diversity in Zostera japonica (Aschers. et Graebn.) for Seagrass Conservation in Brackish Lower Reaches of the Hii River System, Japan

This study examined the genetic diversity and composition of 15 populations of Zostera japonica in the Hii River system, Japan. Genetic and genotypic diversity were consistently higher in populations in the Ohashi River than those in Lake Nakaumi, and the local tidal movements may explain the observed patterns of genetic diversity. Pairwise fixation index values among the populations in Lake Nakaumi were higher than among those in the Ohashi River, even though the ranges of the distances among the populations in the two locations were almost the same. The gene flow from the Ohashi River populations was important for some populations in Lake Nakaumi. The low genotypic diversity and gene flow in Lake Nakaumi seemed similar to those of marginal populations. If this low genotypic diversity and genetic differentiation were partly caused by human activities, the promotion of gene flow should be taken into account in conserving the populations in Lake Nakaumi.     

The cyclopoid copepods,Hemicyclops adhaerens andSaphirella sp., in the Damariscotta River estuary,maine, with a note to their possible relationship

During the 14-month collection period,Hemicyclops always appeared as naupliar stages andSaphirella as immature copepodite stages at 3 stations in the middle and lower estuary.Hemicyclops nauplii were abundant during late spring and summer, with a seasonal maximum of 7448/m³ in late spring at the upstream station.Saphirella stages were observed throughout the year, but higher population densities generally occurred in the summer and fall; the highest density was 3413/m³. Both species were usually more abundant upstream than downstream. The larvae may be life stages of a single bottom-dwelling species,Hemicyclops adhaerens.