Macrophyte detritus in the winter diet of the estuarine mysid,Neomysis americana

Neomysis americana, a common prey item in the diet of estuarine fish, is seasonally abundant in saltmarsh tidal creeks of North Inlet, South Carolina. Visual examination of mysids collected in winter revealed only diatom tests in their guts, with nearly all of the ingesta unidentifiable. Immunological diet analysis provided strong evidence that proteins fromSpartina alterniflora detritus were present in the guts of field-collected mysids. Laboratory determinations of weight-specific ingestion rates for male and female mysids fed particulateS. alterniflora were best described by a curvilinear quadratic function. Ingestion rates ranged from zero to 0.116 mg C ingested per mg C body weight per hr, or greater than 200% of body carbon per day if continuous feeding is assumed. These high ingestion rates may indicate low assimilation efficiency, but ifN. americana’s assimilation efficiency is similar to that of other mysid species, then this mysid may represent an efficient trophic link between saltmarsh macrophyte production and higher trophic levels. The occurrence ofSpartina detritus in the guts of winter mysids suggests that detritivory may be important during periods of scarce food.     

Food availability and the feeding ecology of ichthyofauna of a Ria Formosa (South Portugal) water reservoir

The feeding habits of several fish species in a water reservoir of the Ria Formosa, Portugal, that has similar ecological characteristics to the outside tidal channels, were studied and compared with food availability. The gilthead seabream (Sparus aurata), the most abundant fish species, mainly selected gastropods and bivalves, although occasionally fish and small crustaceans such as tanaids, ostracods, and cumaceans were also selected. Polychaetes, although abundant in the environment, were not particularly selected by any of the fish species studied. The diets of all the species studied were characterized by a large variety of prey, allowing them to survive in environments of low diversity and poor stability, such as coastal lagoons. These fish are largely benthic feeders, essentially eating the epimacroinvertebrates and endomacroinvertebrates and, occasionally, fish.Diplodus vulgaris andDiplodus annularis preferentially selected gastropods and small crustaceans.Spondyliosoma cantharus generally preyed on crustaceans, including the highly mobile epifauma, the mysids, and decapods.Halobatrachus didactylus andAnguilla anguilla, had very diversified diets that included fish.Mullus barbatus were found to have selected all groups of crustaceans and also bivalves. Wrasses, gobies, andDiplodus sargus, all small-sized fish, singled out small crustaceans, gastropods, and bivalves. The Sparids were the least specialized predators, with broader niches than the other species. They preferentially selected molluscs, which were abundant in the environment. A large overlap of diets was observed and competition may be important when fish biomass is high.     

Predation impact on the meiobenthic harpacticoidCanuella perplexa in a lagoon of the Po River Delta,Italy

The impact of predation by juvenile marbled gobies,Pomatoschistus marmoratus, on the meiobenthic harpacticoid copepodCanuella perplexa was investigated at a subtidal station located in a shallow-water, brackish embayment of the Po River delta, northern Italy, in summer and fall 1978. In august, predation mainly centered on adults, with a very large number of prey for each predator; the energy supplied by the harpacticoid is high enough to sustain, almost entirely, the gobies’ daily energy requirement. The situation is different in September and October, when the adult copepod population declines dramatically and predation is shifted to less energy-providing copepodites and marbled gobies sensibly widen their prey spectrum.C. perplexa showed alterations of biological parameters, such as clutch size and average brood size, to cope with such a heavy predation pressure.     

Marine,brackish, and freshwater fish communities in the vegetated and bare shallows of an Australian Coastal River

Fish communities found in the marine, brackish, and freshwater shallows of the Clarence River (New South Wales, Australia) were sampled over a 12-mo period to compare communities inhabiting bare and vegetated substrata. A total of 26,107 fish representing 57 species and 36 families was collected biomonthly suing a 6-mm mesh siene. Permanent residents (i.e., species found throughout the year) were primarily gobies (Gobiidae) and gudgeons (Eleotridae). Juveniles of many species found as adults in other parts of the river were seasonally abundant in the shallows. Most numerous was a small ambassid, the glassy perchlet (Ambassis jacksoniensis), the majority of which was collected from marine and brackish regions of the river. Firetail gudgeons (Hypseleotris compressus) were caught in highest numbers at the freshwater sites. Cluster analysis suggested that fish communities in widely separated vegetated sites were more similar to each other than to those in adjacent bare sites. Shallow vegetated (Zostera capricorni) habitats in the marine region of the river had greatest diversity and highest abundances of fish, particularly during recruitment periods. At these times, juveniles of many commercially important species were captured, including yellowfin bream (Acanthopagrus australis), sea mullet (Mugil cephalus), flat-tail mullet (Liza agentea), tarwhine (Rhabdosargus sarba), luderick (Girella tricuspidata), silver biddy (Gerres subfasciatus), and sand whiting (Sillago ciliata). The vegetated (Vallisneria gigantea) sites in the brackish region also had significantly more species and individuals during recruitment periods (spring) than bare sites. Although freshwater vegetated sites consistently had more individuals than freshwater bare sites, there were no significant differences in species richness between vegetated and bare habitats. The need to conservatively manage shallow-water fish habitats is stressed. *** DIRECT SUPPORT *** A01BY073 00004     

Absolute ages of Quaternary radiolarian datum levels in the equatorial Pacific

Radiolarian assemblages were examined in two Quaternary cores (V24-58; RC11-209) from the tropical Padific Ocean. Eight radiolarian datum levels were identified in each core, and “absolute” ages were estimated for these levels by interpolation between paleomagnetic reversal boundaries previously established for the cores. The tropical radiolarian zonation for the Quaternary proposed by Nigrini (1971) appears to be most useful in terms of the reliability and ease of identification of the proposed zonal boundaries. Our estimated ages for the base of each of these zones are: Buccinosphaera invaginata Zone (Zone 1): 210,000 yr BP; Collosphaera tuberosa Zone (Zone 2): 370,000 yr BP; Amphirhopalum ypsilon Zone (Zone 3): 940,000 yr BP; Anthocyrtidium angulare Zone (Zone 4): 1,700,000 yr BP.A comparison of our age estimates with those of Quaternary radiolarian datum levels in cores from other regions suggests that significant diachroneity on a scale of up to several hundred thousand years may exist for some (and perhaps all) of these “events.” Diachroneity is most readily studied and documented in late Neogene cores where the absolute ages of the magnetic polarity reversals are known most precisely, but may also exist (though difficult to recolve) in earlier Cenozoic sediments. The existence of such diachroneity, if demonstrated through further studies, would have significant implications for our understanding of evolutionary patterns of planktonic communities in different biogeographic regions.     

A Late Glacial–Holocene Tephrochronology for Glacial Lakes in Southern Ecuador

Despite the presence of numerous active volcanoes in the northern half of Ecuador, few, if any, distal tephras have been previously recognized in the southern one third of the country. In this article, we document the presence of thin (0.1–1.0-cm-thick) distal tephras comprising glass and/or phenocrysts of hornblende and feldspar in sediment cores from five glacial lakes and one bog in Las Cajas National Park (2°40′–3°00′S, 79°00′–79°25′W). The lake cores contain from 5 to 7 tephras, and each has a diagnostic major element geochemistry as determined from electron microprobe analysis of 710 glass shards and 440 phenocrysts of feldspar and hornblende. The loss of sodium with exposure to the electron microbeam causes a 10±7 wt.% (±1σ) reduction in Na content, which we empirically determined and corrected for before correlating tephras among the sediment cores. We use a similarity coefficient to correlate among the sediment cores; pair-wise comparison of all tephras generally yields an unambiguous correlation among the cores. Six tephras can be traced among all or most of the cores, and several tephras are present in only one or two of the cores. Twenty-six accelerator mass spectrometry ¹⁴C dates on macrofossils preserved in the sediment cores provide the basis for establishing a regional tephrochronology. The widespread tephras were deposited 9900, 8800, 7300, 5300, 2500, and 2200 cal yr B.P. The oldest tephras were deposited 15,500 and 15,100 cal yr B.P., but these are not found in all cores. Two of the tephras appear correlative with volcaniclastic strata on the flanks of Volcán Cotopaxi and one tephra may correlate with strata on the flanks of Volcán Ninahuilca; both volcanoes are in central Ecuador. The absence of tephras in sediment cores correlative with the numerous eruptions of active volcanoes of the past two millennia implies that the earlier eruptions, which did deposit tephras in the lakes, must have been either especially voluminous, or southerly winds must have prevailed at the time of the eruption, or both.     

Environmental changes in the wetlands of Southern Iraq based on palynological studies

Palynological techniques are useful in reconstructing past environments, especially when other sources of information are lacking. We have embarked on a palynological study of the wetlands in Southern Iraq in an attempt to determine the nature and extent of past plant communities and other conditions prior to the drying of the wetland in the 1990s. Ten 1-m depth cores were collected from selected locations in marshes and shallow open water wetlands in Mesopotamian wetlands of Southern Iraq. Pollen diagrams from three short cores from the Hawizeh wetlands serve as a reference because this site has not been drained. The palynomorphs in these cores were Gramineae, Chenopodiaceae, Typha, Isonandra lanceolata, Bursarea, Artocarpus, Ireantea, Arenga, Crinum, Palmae, Navia, Tofieldia, Ipomorea, Xyris, and Morus. Fungal spores including Polyporisporites, Pluricellaesporites palyadosporites, Fusiformisporites, Spegazzinites indicus, Diporisporites, Plochmopellinites, Lycoperdon, Miliolinites, Dryadosporites constrictus, and Trichothyrites padapakarensis were noteworthy. Charcoal was scattered through the cores and indicate activities associated with human settlements. Many other forms of cuticles, filaments, insects, algae, and foraminifera test linings were also recorded. A second set of pollen samples were analyzed from 160 soil samples from eight cores collected from the wetland area which was dried during the 1990s. These data show a mixture of pollen and spores that could be used to evaluate past vegetation, climatic, and ecological changes. Preliminary results indicated that chenopodiaceous have increased while germinate types have declined which probably reflected desertification and a trend towards a more aeolian landscape during the 1990s. It is hoped that these studies will be useful in establishing conditions of the wetlands prior to destruction and will assist in setting restoration goals in the future. Case studies of one deep borehole (153 m) near Amara city for evaluating late Quaternary history and dig of 3 m depth to evaluate ancient desertification by wetland dryness were taken for correlation and connection with this recent sediment.     

Marsh-creek connectivity: Fish use of a tidal salt marsh in Southern California

Salt marsh habitats influenced by southern California's mixed, semi-diurnal tides are, on average, accessible to fishes less than 16% of the time. However, five species (four natives, one oxotic) and a variety of juvenile and adult size classes were collected on the marsh surface during a year-long sampling from June 1997 through June 1998 at Sweetwater Marsh National Wildlife Refuge on San Diego Bay.Fundulus parvipinis andGillichthys mirabilis were the most abundant fish species using the marsh. Analyses of their guts revealed that the marsh surface provides a rich foraging area for fishes on high spring tides.F. parvipinnis with marsh access consumed six times as much food as fishes restricted to creek habitats (on a g-food g-fish^?1 basis) and also fed on additional prey types. Because the salt marsh is an important foraging area for fishes, we recommend that restoration projects (especially those intended to mitigate lost fish habitat) include vegetated areas with interconnecting tidal creeks.     

Some life history aspects of the seaboard goby (gobiosoma ginsburgi) in Rhode Island

This paper represents the first report of adultG. ginsburgi from Rhode Island waters since 1938. Gobies were collected only from subtidal shell communities in high salinity waters. Seaboard gobies eat a variety of benthic invertebrates but feed most heavily on harpacticoid copepods. Gravid females collected in July contained one size class of ova indicating a single spawning per season. Egg counts ranged from 1268 to 1977 per female. Larval densities indicate that peak spawning occurs in July and suggest thatG. ginsburgi is more abundant in the Sakonnet River and nearby Narragansett Bay than previously reported.     

Stable isotopes and cellulase activity as evidence for detritus as a food source for juvenile Gulf menhaden

Menhaden are one of the most abundant components of fish communities in Gulf and Atlantic estuaries. Juvenile menhaden have been reported to have zooplankton, phytoplankton, andSpartina-derived detritus in their guts. However, there has been disagreement over the importance of the detritus as a food source. We show, using physiological and stable isotope evidence, that detritus can be used by juvenile Gulf menhaden. Their diet is very roughly 30% detritus- and 70% plankton-based.     

High-resolution saturated hydraulic conductivity logging of borehole cores using air permeability measurements

Saturated hydraulic conductivity (K _s) is one of the most important parameters determining groundwater flow and contaminant transport in both unsaturated and saturated porous media. The hand-held air permeameter technique was investigated for high-resolution hydraulic conductivity determination on borehole cores using a spatial resolution of ～0.05 m. The suitability of such air permeameter measurements on friable to poorly indurated sediments was tested to improve the spatial prediction of classical laboratory-based K _s measurements obtained at a much lower spatial resolution (～2 m). In total, 368 K _s measurements were made on ～350 m of borehole cores originating from the Campine basin, northern Belgium, while ～5,230 air permeability measurements were performed on the same cores, resulting in a K _s range of seven orders of magnitude. Cross-validation demonstrated that, using air permeameter data as the secondary variable for laboratory based K _s measurements, the performance increased from R ²?=?0.35 for ordinary kriging (laboratory K _s only) to R ²?=?0.61 for co-kriging. The separate treatment of horizontal and vertical hydraulic conductivity revealed considerable anisotropy in certain lithostratigraphical units, while others were clearly isotropic at the sample scale. Air permeameter measurements on borehole cores provide a cost-effective way to improve spatial predictions of traditional laboratory based K _s.     

Palynostratigraphy of two Neogene boreholes from the northwestern portion of the Solimões Basin,Brazil

Palynological studies in large basins yield the most significant results for understanding basinal and continental evolution. We selected the Solimões Basin in the upper reaches of the Amazon River as our study site due to the availability of drill cores in this jungle-covered terrain. The purpose of this paper is contribute to the palynological knowledge and to evaluate the palynostratigraphic schemes of Venezuelan (LM sheme) and Colombia (Jea sheme) applied for large basin situated in the Amazon jungle. Taxonomic studies of the analysed samples indicate a significant presence of Grimsdalea magnaclavata, suggesting both cores represent the Mio-Pleistocene Solimões and Iça Formations. These results are integrated and correlated with previously collected data for the entire basin, Venezuelan and Colombia. The ages attributed to the Miocene intervals of the boreholes studied vary according to the palynostratigraphic scheme. According to the biostratigraphy based on data from Venezuelan (LM sheme), the borehole 1AS-51-AM presents range in Early Miocene–Early Pliocene and from Middle Miocene–Early Pliocene in 1AS-52-AM. When the data from Colombia (Jea sheme) is used, the ages range from the Middle Miocene–Late Miocene in both boreholes. The differences between the results of two biostratigraphic schemes indicate the existence of distinct stratigraphic arrangements recorded in palynoflora of the Brazilian Amazon.     

Stage-specific spatial and temporal variability in the diets of larval winter flounder (<Emphasis Type="Italic">Pseudopleuronectes americanus</Emphasis>) in a northeastern U.S. estuarine nursery

Collections of winter flounder (Pseudopleuronectes americanus) larvae were made biweekly from March to May in 1999 and 2000 in the Navesink River-Sandy Hook Bay estuarine system, New Jersey, to determine stage-specific spatial and temporal variability in diets. Relatively high percentages of larvae with empty guts were found at low water temperatures. Percentages of empty guts did not differ by larval stage (preflexion and postflexion) or region of collection (river and bay). There was high intraregional variability in percentages of larvae with empty guts. Nauplii, invertebrate eggs, and polychaete larvae were dominant prey items followed by tintinnids, bivalve and gastropod veligers, and diatoms. Ontogenetic dietary shifts were evident in both years. Preflexion winter flounder largely consumed nauplii, invertebrate eggs, and tintinnids; postflexion winter flounder consumed the largest prey (polychaete larvae) but also retained small prey items in their diets. Water temperature significantly affected the percentages of larvae feeding on nauplii (p<0.05) and tintinnids (p<0.08) in 2000. Region of collection was not significantly related to diets because of high intraregional variability. Fine scale spatial (within regions, stations were approximately 3 km apart) and temporal (weeks) dietary variation of larval winter flounder could result in accompanying variation in development, growth stage duration, and survival.     

A chlorine isotope study of DSDP/ODP serpentinized ultramafic rocks: Insights into the serpentinization process

Eight DSDP/ODP cores were analyzed for major ion concentrations and δ³⁷Cl values of water-soluble chloride (δ³⁷Cl_WSC) and structurally bound chloride (δ³⁷Cl_SBC) in serpentinized ultramafic rocks. This diverse set of cores spans a wide range in age, temperature of serpentinization, tectonic setting, and geographic location of drilled serpentinized oceanic crust. Three of the cores were sampled at closely spaced intervals to investigate downhole variation in Cl concentration and chlorine isotope composition.The average total Cl content of all 86 samples is 0.26 ± 0.16 wt.% (0.19 ± 0.10 wt.% as water-soluble Cl (X_WSC) and 0.09 ± 0.09 wt.% as structurally bound Cl (X_SBC)). Structurally bound Cl concentration nearly doubles with depth in all cores; there is no consistent trend in water-soluble Cl content among the cores. Chlorine isotope fractionation between the structurally bound Cl⁻ site and the water-soluble Cl⁻ site varies from − 1.08‰ to + 1.16‰, averaging to + 0.21‰. Samples with negative fractionations may be related to reequilibration of the water-soluble chloride with seawater post-serpentinite formation. Six of the cores have positive bulk δ³⁷Cl values (+ 0.05‰ to + 0.36‰); the other two cores (173-1068A (Leg-Hole) and 84-570) have negative bulk δ³⁷Cl values (− 1.26‰ and − 0.54‰). The cores with negative δ³⁷Cl values also have variable Cl⁻ / SO₄² ratios, in contrast to all other cores. The isotopically positive cores (153-920D and 147-895E) show no isotopic variation with depth; the isotopically negative core (173-1068A) decreases by ∼1‰ with depth for both the water-soluble and structurally bound Cl fractions.Non-zero bulk δ³⁷Cl values indicate Cl in serpentinites was incorporated during original hydration and is not an artifact of seawater infiltration during drilling. Cores with positive δ³⁷Cl values are most likely explained by open system fractionation during hydrothermal alteration, with preferential incorporation of ³⁷Cl from seawater into the serpentinite and loss of residual light Cl back to the ocean. Fluid / rock ratios were probably low as evidenced by the presence of water-soluble salts. The two isotopically negative cores are characterized by a thick overlying sedimentary package that was in place prior to serpentinization. We believe the low δ³⁷Cl values of these cores are a result of hydration of ultramafic rock by infiltrating aqueous pore fluids from the overlying sediments. The resulting serpentinites inherit the characteristic negative δ³⁷Cl values of the pore waters. Chlorine stable isotopes can be used to identify the source of the serpentinizing fluid and ultimately discern chemical and tectonic processes involved in serpentinization.     

Deglaciation, basin formation and post-glacial climate change from a regional network of sediment core sites in Ohio and eastern Indiana

Many paleoclimate and landscape change studies in the American Midwest have focused on the Late Glacial and early Holocene time periods (~ 16–11 ka), but little work has addressed landscape change in this area between the Last Glacial Maximum and the Late Glacial (~ 22–16 ka). Sediment cores were collected from 29 new lake and bog sites in Ohio and Indiana to address this gap. The basal radiocarbon dates from these cores show that initial ice retreat from the maximal last-glacial ice extent occurred by 22 ka, and numerous sites that are ~ 100 km inside this limit were exposed by 18.9 ka. Post-glacial environmental changes were identified as stratigraphic or biologic changes in select cores. The strongest signal occurs between 18.5 and 14.6 ka. These Midwestern events correspond with evidence to the northeast, suggesting that initial deglaciation of the ice sheet, and ensuing environmental changes, were episodic and rapid. Significantly, these changes predate the onset of the Bølling postglacial warming (14.8 ka) as recorded by the Greenland ice cores. Thus, deglaciation and landscape change around the southern margins of the Laurentide Ice Sheet happened ~ 7 ka before postglacial changes were felt in central Greenland.     

Chemical differentiation of the Galilean satellites of Jupiter: 4. Isochemical models for the compositions of Io, Europa, and Ganymede

Models for the composition and structure of the Galilean satellites of Jupiter (Io, Europa, and Ganymede) were constructed using geophysical data provided by the Galileo mission on the mass, average density, and moment of inertia, as well as thermodynamic data on the equation of the state of water, high-pressure ices, and meteoritic materials. The distribution of density, pressure, temperature, and gravity acceleration in the interiors of the satellites was determined. A simulation of the internal structure of the satellites showed the possibility of identical bulk compositions for water-free Io and the rock-iron cores of Europa and Ganymede (i.e., satellites without their outer ice-water shells). The sizes of the satellites’ cores (Fe with 10 wt % S) and the thicknesses of the ice-water shells of Europa (120 km) and Ganymede (900 km) were also estimated. These satellites contain 7 and 47% H₂O, respectively. The radii of Fe-10% S cores are 737 km for Io, 695 km for Ganymede, and 576 km for Europa. The ratios of the radii and masses of the Fe-S scores and rock-iron cores of Io, Ganymede, and Europa are almost identical and equal R(Fe-10%S core)/R _Cor = 0.4 and M(Fe-10% S core)/M _Cor = 10.55 ± 0.3 wt %. It was shown that the geochemical parameters of the rock-iron constituent of the satellites are similar to the material of L/LL chondrites. The silicate fraction of the satellites contains about 16 wt % FeO and shows an Fe/Si mass ratio of 0.53. The total iron to silicon mass ratio is also identical in the three satellites: (Fe_tot/Si)_Cor = 0.99 ± 0.02. This value is different from that in the bulk compositions of the most oxidized carbonaceous chondrites and the most reduced H chondrites. Io, Europa, and Ganymede could be formed in the accretion disk of Jupiter from a material similar to L/LL chondrites under relatively low temperatures, not higher than the evaporation temperature of Fe and Fe-Mg silicates.     

The peat bog at Zinnwald-Georgenfeld revisited after 25 years: Geochemical investigation of water,Sphagnum moss and peat cores

From 1992 to 1994, trace metal concentrations of bog water, Sphagnum mosses and peat cores of the bog “Georgenfelder Hochmoor” at Zinnwald-Georgenfeld in the Eastern Ore Mountains (Germany) were investigated. A sampling campaign in September 2019 allows the comparison of the older measurements with today's trace metal concentrations. No changes were found in the bog waters, while the trace metal concentrations of the Sphagnum mosses have decreased significantly. Due to the low growth rate of the peat and despite certain heterogeneity between the peat cores, the investigated elemental data for the peat sampled in the 1990s and in 2019 are in the same concentration range. The maximum concentrations are measured in the upper samples of all peat cores for the analysed elements (except sulphur). Compared to upper crustal data, a different behaviour of the elements is observed: Cr, Sc, Ti, and V, rare earth elements show crustal ratios, while Al and Si are also influenced by crust-air fractionation. Cd, Cu, Ni, Pb, and Zn are additionally enriched by anthropogenic atmospheric inputs from industry and transport. These results confirm the assumption that peat cores record past atmospheric deposition.     

Trace analysis of hydrocarbons in coral cores from Saudi Arabia

As part of a long-term environmental assessment of the impact of the 1991 Gulf War on coral reefs, the Australian Institute of Marine Science (AIMS) conducted growth and chemistry studies on coral cores from the Arabian Gulf. Twenty-eight cores were collected from four coral reefs located offshore from Saudi Arabia.Annual coral growth bands surrounding the 1991 oil spill were analysed in selected cores. Additionally, in cores that extended to the early 1980s, annual layers from 1980 to 1986 were analysed for possible residues from the 1983–4 oil spill caused by the Nowruz oil field blowout during the Iraq–Iran war. Both major spill events were targeted to provide additional confidence in relating oil concentrations to specific pollution events. We detected petroleum biomarkers in several coral annual bands related to the major pollution events. However, the oil remaining in these cores has been altered over time and the biomarker ratios found in these oil residues differed from Gulf crude oils.The concentrations of hydrocarbons were compared with the growth parameters of the coral cores. Only one sample may have recorded an “impact” of oil exposure. There was no other correspondence between slight changes in growth parameters between years and the trace chemistry. Therefore, chemical analysis enabled detection of the exposure incident, but provided no insight into the amount of oil to which the coral had been exposed. The chemical data can only infer biological impact if growth was significantly decreased.The average coral growth characteristics of Porites from the four sites in the Arabian Gulf were normal, as predicted from the average water temperatures of the region. There was an indication of an overall decline in growth over time, which should be monitored in the future.     

Formation of supermassive black holes due to the tidal deceleration of stellar black holes, globular clusters, and galaxies

The formation and evolution of supermassive (10²?10¹⁰ M _⊙) black holes (SMBHs) in the dense cores of globular clusters and galaxies is investigated. The raw material for the construction of the SMBHs is stellar black holes produced during the evolution of massive (25?150M _⊙) stars. The first SMBHs, with masses of ～1000M _⊙, arise in the centers of the densest and most massive globular clusters. Current scenarios for the formation of SMBHs in the cores of globular clusters are analyzed. The dynamical deceleration of the most massive and slowly moving stellar-mass (< 100M _⊙) black holes, accompanied by the radiation of gravitational waves in late stages, is a probable scenario for the formation of SMBHs in the most massive and densest globular clusters. The dynamical friction of the most massive globular clusters close to the dense cores of their galaxies, with the formation of close binary black holes due to the radiation of gravitational waves, leads to the formation of SMBHs with masses ? 10³ M _⊙ in these regions. The stars of these galaxies form galactic bulges, providing a possible explanation for the correlation between the masses of the bulge and of the central SMBHs. The deceleration of the most massive galaxies in the central regions of the most massive and dense clusters of galaxies could lead to the appearance of the most massive (to 10¹⁰ M _⊙) SMBHs in the cores of cD galaxies. A side product of this cascade scenario for the formation of massive galaxies with SMBHs in their cores is the appearance of stars with high spatial velocities (> 300 km/s). The velocities of neutron stars and stellar-mass black holes can reach ～10⁵ km/s.     

Short-term effects of salinity reduction and drainage on salt-marsh biogeochemical cycling andSpartina (cordgrass production

To assess the biogeochemical effects of tidal restrictions on salt-marsh sulfur cycling and plant growth, cores of short-formSpartina alterniflora peat were desalinated and kept either waterlogged or drained in greenhouse microcosms. Changes in netSpartina production, and porewater and solid phase chemistry of treated cores were compared to natural conditions in the field collection site over a 21-mo period. Net production among treatments increased significantly in drained and waterlogged peat compared to field conditions during the first growing season. Constantly high sulfide in waterlogged cores accompanied reduced plant growth. Aeration invigorated growth in draimed cores but led to oxidization of sulfide minerals and to lowered pH. During the second growing season, growth declined in the drained treatment, probably because of acidification and decreased dissolved inorganic nitrogen. Results are pertinent to the success of current wetland protection and restoration activities in the coastal zone.