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1.
The Atlantic ribbed mussel, Geukensia demissa, is found in salt marshes along the North American Atlantic Coast. As a first step to study the possibility of future cultivation and harvest of ribbed mussels for nutrient removal from eutrophic urban environments, the feeding behavior of ribbed mussels in situ was studied from July to October 2011. Two locations approximately 80 km apart were used as study sites: Milford Harbor (Connecticut; 41°12′42.46″N, 73°3′7.75″W) and Hunts Point (Bronx, New York; 40°48′5.99″N, 73°52′17.76″W). Total particulate matter was higher at Hunts Point than at Milford Harbor, but the organic content was higher at Milford than at Hunts Point. The relatively low quantity of organic content in Hunts Point seston resulted in a much higher production of pseudofeces by mussels. Mussel clearance and absorption rates were higher at Milford Harbor than at Hunts Point. Nevertheless, mussels at both sites had the same absorption efficiency, suggesting that mussels are able to adapt to conditions at both locations. Ribbed mussels decreased clearance rate when the seston quantity was high at both sites. At Hunts Point, ribbed mussels increased the gut transit time of ingested particles when the amount of inorganic particulates in the water increased. This study does not quantify nutrient removal capacity of G. demissa; however, the environmental tolerance demonstrated here, and current lack of commercial harvest, suggests that this species may be a good candidate for nutrient bioextraction in highly impacted urban environments.  相似文献   

2.
The distribution of macroinvertebrates on Connecticut tidal marshes corresponds well with that reported for other marshes along the Atlantic and Gulf coasts of the United States. The greatest densities and biomass of the ribbed mussel,Geukensia demissa, were found on marshes in the central and western part of the state where both the annual production ofSpartina alterniflora and tidal range are large. *** DIRECT SUPPORT *** A01BY019 00011  相似文献   

3.
Phragmites australis has been invading Spartina-alterniflora-dominated salt marshes throughout the mid-Atlantic. Although, Phragmites has high rates of primary production, it is not known whether this species supports lower trophic levels of a marsh food web in the same manner as Spartina. Using several related photochemical and biological assays, we compared patterns of organic matter flow of plant primary production through a key salt marsh metazoan, the ribbed mussel (Geukensia demissa), using a bacterial intermediate. Dissolved organic matter (DOM) was derived from plants collected from a Delaware Bay salt marsh and grown in the laboratory with 14C-CO2. Bacterial utilization of plant-derived DOM measured as carbon mineralization revealed that both species provided bioavailable DOM to native salt marsh bacteria. Total carbon mineralization after 19 days was higher for Spartina treatments (36% 14CO2 ± 3 SE) compared with Phragmites treatments (29% ±2 SE; Wilcoxon–Kruskal–Wallis rank sums test, P < 0.01). Pre-exposing DOM to natural sunlight only enhanced or decreased bioavailability of the DOM to the bacterioplankton during initial measurements (e.g., 7 days or less) but these differences were not significant over the course of the incubations. Mixtures of 14C-labeled bacterioplankton (and possibly organic flocs) from 14C-DOM treatments were cleared by G. demissa at similar rates between Spartina and Phragmites treatments. Moreover, 14C assimilation efficiencies for material ingested by mussels were high for both plant sources ranging from 74% to 90% and not significantly different between plant sources. Sunlight exposure did not affect the nutritional value of the bacterioplankton DOM assemblage for mussels. There are many possible trophic and habitat differences between Spartina- and Phragmites-dominated marshes that could affect G. demissa but the fate of vascular plant dissolved organic carbon in the DOM to bacterioplankton to mussel trophic pathway appears comparable between these marsh types.  相似文献   

4.
Ribbed mussels (Geukensia demissa) help form the basis of highly productive salt marshes along the Atlantic coast of North America, in southern New England, and further south. Little is known about their ecology and reproductive biology at more northern latitudes (Maritime Canada; >43o N). As a step in determining the sustainability of ribbed mussel populations near the northern limit of their range (Northumberland Strait, Gulf of St. Lawrence, Canada), gametogenesis and spawning were monitored over 3 years (May–August 2012, June–November 2014, and April–October 2015) at four sites spanning ~100 km of coastline. These sites are typically ice-covered from mid-December to March or April. The onset of gametogenesis was later, the reproductive stages on any given date were more varied, and the reproductive season was shorter than for southern populations of ribbed mussels. Oocyte density and size did not vary among sites, indicating similar site-level processes, but did vary among years. Oocyte density and size varied greatly among mussels at a given site, and within a single gonad. This highlights the importance of individual variability, perhaps related to mussel location within a marsh, and the effects of nutrients and temperature on gonads. Accounting for the individual-level variability, reproductive output was estimated at ~105 oocytes per ripe female mussel, which is within the fecundity estimates for other marine bivalve broadcast spawners.  相似文献   

5.
Paravortex gemellipara is reported from its type hostGeukensia (=Modiolus) demissa and from two new hostsIschadium (=Brachidontes) recurvum andMytilopsis (=Congeria) leucopheata. Its range on the Atlantic seaboard is extended from Woods Hole, Massachusetts south to the lower Chesapeake Bay. The worm is also reported from the Gulf of Mexico at Galveston Bay, Texas. The presence of dermal protuberances and posterior adhesive areas bearing mucous strands is recorded. Mature worms were found living in the digestive tract of their host, contrary to the findings of previous investigators who reported them from the gill and kidney.  相似文献   

6.
Age structure, recruitment, and survivorship of a Jamaica Bay, New York ribbed mussel (Geukensia demissa) population were studied over nine years at two shore elevations. Mussels were collected in November (following seasonal growth and recruitment) and March (to assay over-winter mortality). Larval recruits (0-class) averaged 55% of the population at the marsh edge compared with <9% at the higher elevation (6 m upshore). High larval settlement at the edge apparently depletes the larval supply available for settlement within the marsh interior. At the edge, the population generally contained 7 monotonically decreasing age classes compared to 15–20 age classes at the interior site. At the interior site, most 0-class mussels may not directly settle into existing mussel aggregations, but instead immigrate over a period of two years following settlement. The linear survivorship curve at the edge reflects 40–50% mortality every year. Over-winter mortality is sensitive to winter ice conditions. Simulations of reproductive output based on survivorship and fertility data combined suggest that mussel cohorts living in the marsh may approach the life time reproductive output of marsh edge mussels after about 15 years, a life span which is not uncommon at higher shore levels.  相似文献   

7.
Ribbed mussel populations at two levels of the intertidal shore were studied for 3 yr at a salt marsh site in Jamaica Bay (New York). Length-specific dry body weight was determined monthly and shell growth was monitored between April and November of each year. Production (Pi) was measured as monthly changes in body dry weight. Annual reproductive output (PR) was estimated indirectly for mussels between 10 mm and 80 mm by determining the gain in body weight prior to spawning (Weight Gained Method). Using a second method (Basal Weight Method), monthly rates of somatic production (Pg) were determined by assuming that, as mussels grow in length, a fraction of monthly Pt is allocated to increasing body weight. The monthly production allocated to growth (Pg) was estimated based on the length-specific body weight (basal weight) in March, when body weights in these populations begin to increase due to gametogenesis. Monthly rates of reproductive output (Pr) were then estimated be substraction as the difference between monthly Pt and Pg. Total PR determined by both methods were very similar. Shell and body growth were concurrent in sexually immature mussels, but body weight preceeded shell growth in older, larger animals. Annual shell increments were correlated with annual PG. In sexually mature mussels, Pr preceeds Pg in larger mussels, that is, allocations of net production to reproduction and somatic growth diverge in time with increasing shell length. Between April and November, shell growth rates were correlated with water temperature. At the higher shore level, mussels allocated a much smaller proportion of total production to growth, exceeding the reproductive effort of the lower-shore population. Variation in mussel production between years probably is related to variability in nannoplankton biomass. Although mussels higher on the shore can reduce somatic growth in order to increase fecundity and reproductive effort, total reproductive output is much reduced as compared to the marsh edge.  相似文献   

8.
Depth-specific sampling at a single location was used to examine the vertical distribution of pediveliger larvae of bivalve mollusks in the York River, an estuary of Chesapeake Bay, Virginia. The water column at the sampling site was usually well mixed, lacking consistent temperature or salinity gradients for larvae. Four species showed strong vertical stratification when collected simultaneously at three depths. Pediveliger stage larvae of a clam (Cyrtopleura costata), an oyster (Crassostrea virginica), and a shipworm (Bankia gouldi) were most abundant near the benthos, and least abundant near the surface. A mussel (Geukensia demissa), showed the reverse trend, with most pediveliger larvae near the surface. Tidal stage had a slight effect on two species (C. costata andC. virginica), but only to increase the relative abundance of larvae near the benthos during flood tide. Otherwise, neither tidal phase nor light levels (night versus day) had detectable effects on distribution patterns. Sampling very close to the sediment-water interface provided no evidence that pediveliger larvae spent a significant proportion of their time in this location. While the behavior of precompetent bivalve larvae may tend to retain them within an estuary, that of competent-to-metamorphose pediveliger larvae does not appear to have that function. Pediveliger larvae may regulate their depth to best locate potential settlement substrate. Such an hypothesis is consistent with adult habitat zones of at least some of these species in Chesapeake Bay. Removing competent-to-settle larvae from analyses of larval distributions in estuaries will enhance or clarify depth distribution patterns observed for earlier-stage larvae.  相似文献   

9.
Understanding methane emissions from natural sources is becoming increasingly important with future climactic uncertainty. Wetlands are the single largest natural source of methane; however, little attention has been given to how biota and interactions between aboveground and belowground communities may affect methane emission rates in these systems. To investigate the effects of vegetative disturbance and belowground biogeochemical alterations induced by biota on methane emissions in situ, we manipulated densities of Littoraria irrorata (marsh periwinkle snails) and Geukensia granosissima (gulf ribbed mussels) inside fenced enclosures within a Spartina alterniflora salt marsh and measured methane emissions and sediment extracellular enzyme activity (phosphatase, β-glucosidase, cellobiohydrolase, N-acetyl-β-D-glucosaminidase, peroxidase, and phenol oxidase) over the course of a year. Changes in snail density did not have an effect on methane emission; however, increased densities of ribbed mussels significantly increased the emission of methane. Sediment extracellular enzyme activities for phosphatase, cellobiohydrolase, N-acetyl-β-D-glucosaminidase, and phenol oxidase were correlated to methane emission, and none of the enzymes assayed were affected by the snail and mussel density treatments. While methane emissions from salt marsh ecosystems are lower than those from freshwater systems, the high degree of variability in emission rates and the potential for interactions with naturally occurring biota that increase emissions warrant further investigations into salt marsh methane dynamics.  相似文献   

10.
Identifying differential population structure within metacommunities is key toward describing the mechanisms that maintain biodiversity in natural systems. At both local and regional scales on the North American Atlantic coast, we assessed phylogeographic and genetic diversity patterns of six common salt marsh invertebrates using equivalent sampling schemes and sequence data from the same mitochondrial locus. In general, our results suggest little genetic structure across four previously sampled biogeographic regions and a slight increase in genetic diversity from northern to southern areas; however, two of the species (Geukensia demissa and Uca pugilator) exhibited significant differentiation between the northernmost populations and other regions, consistent with a number of previous studies. Although the minimal genetic structure recovered in this community is consistent with expectations based on the larval life history of the species examined, confirmation of this result suggests that latitudinal shifts in ecological interactions in salt marsh systems are environmentally driven, rather than due to heritable adaptation.  相似文献   

11.
We reared larval zebra mussels,Dreissena polymorpha, and quagga mussels,D. bugensis, through and beyond metamorphosis (settlement) at salinities of 0–8‰. Juvenile zebra mussels gradually acclimated to 8‰ and 10‰ have been reared at these salinities for over 8 mo. Tolerance to both higher temperatures and higher salinities increases with larval age in both species (though zebra mussel embryos and larvae have a greater degree of salinity tolerance than quagga mussel embryos and larvae). Thus, only 6% of 3-day-old zebra mussel veligers survived after exposure to 4‰ for 8 additional days, whereas there was 22% survival of veligers placed in 4‰ at day 13 and grown to settlement 11 d later. Zebra mussel pediveligers, acclimated to increasing salinity in 2‰ increments beginning at day 23, continued to survive and grow in 8‰ after 5-mo exposure, though the growth rates of these juveniles were significantly less than those of juveniles reared in lower salinities. Quagga mussels did not metamorphose and settle as quickly as zebra mussel pediveligers. No quagga mussel pediveligers had settled before exposure to artificial fresh water (AFW), 2‰ 4‰, 6‰, and 8‰ on day 30. Percent settlement of these quagga mussel juveniles (based on 100% survival at the start of experiments on day 30) was 90% in AFW, 67% at 2‰, 69% at 4‰, 46% at 6‰, and 0.1% at 8‰.  相似文献   

12.
Mussel shells have been used in a number of paleoecological and environmental studies. The interpretation of stable carbon isotopic composition of shell material is still controversial. The carbon for shell carbonate precipitation can either be derived from ambient dissolved inorganic carbon (DIC), with shells recording environmental signals, or from metabolic CO2, with the potential to disguise environmental signals. To gain insight into this question, we investigated four nearly 100-yr long-term records of aragonite shells from an extant freshwater bivalve species, the endangered freshwater pearl mussel (Margaritifera margaritifera L.). Single growth increments of the outer prismatic and the inner nacreous zones were successfully and easily separated with a simple heat treatment for chronological analyses of δ13C in single layers of each zone. Autocorrelation and semivariance statistical methods reveal that mussels show distinct individual signal patterns, which extend up to 25 yr. Signal patterns are reliably reproduced with replicate samples from defined layers within one shell and show similar patterns with a slight offset for inner nacreous and outer prismatic layers for individual animals. Mussels exposed to the same environmental conditions exhibit distinct and contradictory signature patterns, which do not match between individuals. This observation can only be explained by strong metabolic influences on shell precipitation. Environmental changes in pH, temperature, electric conductivity and atmospheric carbon signature had no or little (<5%) influence, whereas body tissue protein and body tissue δ13C signatures negatively correlated with the youngest produced shell δ13C signatures, indicating that respiration causes a preferential loss of light isotopes from body mass and an inverse enrichment in shell aragonite. Hence, the shells of the freshwater pearl mussel yield a long-term record of metabolic activity, whereas the use of δ13C in these shells as recorder for environmental signals is questionable. This may also be true for shells from other species, for which metabolic carbon incorporation has been acknowledged.  相似文献   

13.
Monthly field sampling of active animals in a Louisiana coastal salt marsh monitored changes in size class frequency distributions, ovarian development of females, and rates of egg extrusion for two species ofUca endemic to the Gulf of Mexico. Ovigerous females occurred no earlier than February forUca spinicarpa and April forUca longisignalis. Peak percentages of ovigerous females were observed in June 1992 forUca longisignalis (67%) and in March 1993 forUca spinicarpa (85%). Peaks in ash-free dry weight (AFDW, in g) of females coincide with peak periods of ovarian development and subsequent ovigery. Mean biomass as AFDW of males and females combined forUca longisignalis was 0.26 g individual?1 and forUca spinicarpa was 0.17 g individual?1. A significant correlation existed between AFDW and carapace width in both species, males and females.U. longisignalis appears to be of warm-temperate lineage, and its reproductive activity is the more seasonally restricted, with later ovarian development, earliest egg laying delayed to late spring, and peak ovigery in summer. In keeping with putative tropical affinities ofUca spinicarpa, ovarian development is episodic over a longer-period from late winter to summer, and eggs are produced earlier in the year. The more striking seasonality in reproductive activity and biomass peaks forUca longisignalis may also reflect some nutritional dependency on temperate, annual marsh plants that characterize its preferred habitats.  相似文献   

14.
Studies of the chemical characteristics of mussels and clams in seafloor hydrothermal fields are important for understanding mass fluxes and elemental partitioning from hydrothermal vents into the biosphere, metal bioaccumulation of seafloor hydrothermal ecosystems, and the sources and sinks of biogeochemical and fluid cycles. We are the first to measure the mineral, major, trace and rare earth element, and carbon and oxygen isotope compositions of mussels (Bathymodiolus platifrons) and clams (Conchocele bisecta) from the Tangyin and Yonaguni Knoll IV hydrothermal fields in the southwestern Okinawa Trough. Mineralogical analysis shows that the carbonate shells of the mussel and clam samples are mainly composed of calcite and aragonite. Metal elements exhibit linear correlations in the shells (e.g., V and U) and tissues (e.g., Li and Rb) of the mussels and clams, suggesting that not all positive correlations of elements in tissues are inherited by the shells. V/As, Ca/Sr, and Fe/Cr ratios in the mussels and clams are close to those in the seawater, indicating that element ratios of seawater might be inherited by the mussels and clams. In addition, the Fe/Cr ratio of the shells of both mussels and clams can be used to trace the local seawater composition.The total LREE concentrations of mussel and clam tissue samples are higher than those of the mussel and clam shell samples, are similar to the hydrothermal fluids, exhibit LREE enrichment (LaCN/NdCN ratios = 1.86-32.1), and no or only slightly negative Eu anomalies, indicating that benthic animals are a sink of LREEs from hydrothermal fluids, and that the Eu/Eu* ratios of fluids change when fluids are incorporated into the tissues of the mussels and clams. In addition, the δ13C values of mussel shell samples are heavier than those of the clam shell samples in the hydrothermal field, indicating that more than one carbon source may be involved in defining the δ13C compositions of the shells. The majority of the δ18O values of clam shell samples fall in the range of δ18O values of the mussel shell samples, and are close to the hydrothermal fluid δ18OH2O values, implying that the δ18O values of mussel and clam shell carbonate is influenced by the hydrothermal environment (magmatic water and fluid dilution with seawater).  相似文献   

15.
The feeding behavior of three species of mussels, the native Ischadium recurvum and the invasives Mytella charruana and Perna viridis, was studied in an invaded ecosystem in Florida (USA). In situ feeding experiments using the biodeposition method were performed along a salinity gradient in four different locations along the St. Johns River. Water characteristics, such as salinity, temperature, dissolved oxygen, and seston loads, were recorded to identify relationships between these variables and the feeding behavior of the mussels. Feeding behavior of the species varied by study site. Clearance, filtration, organic ingestion, and absorption rates of I. recurvum were negatively affected by salinity. For the invasive mussel, M. charruana, rejection was positively related to salinity while total ingestion, organic ingestion, and absorption rates were positively related to the percentage of organic matter in the seston. For P. viridis, total and organic ingestion rates were negatively affected by salinity but positively affected by total particulate matter. Condition indices for P. viridis and M. charruana were 13.16?±?0.64 and 6.63?±?0.43, respectively, compared to 4.82?±?0.41 for the native species I. recurvum, indicating that these mussels are well adapted to the environmental conditions in the area. This study indicates that the three species have different preferred habitats because of their specific responses to water characteristics. Thus, the invasive mussels will not totally occupy the niche of the native mussel in Florida despite overlapping zones. These data may help identify potential invaded areas and understand the extent of the invasion.  相似文献   

16.
Filtration rates and oxygen consumption rates were measured in mussels (Mytilus edulis) with and without pea crabs (Pinnotheres maculatus). Noninfested mussels had a significantly higher rate of oxygen consumption per hour (0.578 ml±0.012) than did infested mussels (0.352 ml±0.012). There was no significant effect of pea crab size on mussel respiration. Filtration rates of infested mussels were significantly lower than those of uninfested mussels. Assimilation efficiency was not significantly affected by pea crab infestation. The relationship between body size and oxygen consumption inP. maculatus is given by the following equation: {ie264-1} W0.626, where {ie264-2} is oxygen uptake (ml h?1), and W is dry weight (g). There was no difference between the sexes. It is concluded that the decreased oxygen consumption observed in infested mussels is not due to limitation of oxygen availability, but rather reflects a real metabolic response to the presence of the symbiont and the concomittant deprivation of food to the host. The effect is probably reversible, that is, damage can be compensated for after the symbiont has vacated the mussel, depending upon the period of infestation. Our results indicate that the mussels infested by pea crabs may be at an energetic disadvantage relative to mussels without pea crabs.  相似文献   

17.
Mean daily consumption rates on Mytilus spp. were compared among juveniles of the non-indigenous Carcinus maenas, juveniles of the indigenous Cancer irroratus, and adults of the indigenous Dyspanopeus sayi between June and August 2005 to assess the relative impact of juvenile C. maenas in field (Benacadie Channel (45°54′ N, 60°53′ E), Bras d’Or Lakes, Nova Scotia, Canada) and laboratory experiments. This study examined: (1) whether consumption rates in a field setting vary among species; (2) the effect of laboratory and field settings on species-specific consumption rates, and whether rates vary between settings for each species; and (3) the effects of temperature and salinity on the consumption rates of these species. In field experiments, there was no significant difference in consumption among C. maenas, C. irroratus, and D. sayi (0.100?±?0.067, 0.450?±?0.189, and 0.800?±?0.423 mussels crab?1 d?1, respectively). However, both C. maenas and C. irroratus consumed two to four times more prey in the laboratory than in the field. D. sayi prey consumption was also greater (although not significant) in the laboratory than in the field. In the laboratory, consumption rate was greater for C. irroratus in salinities of 26 than 17 (2.75 and 1.69–1.81 mussels crab?1 d?1, respectively), and in 17°C than 13°C (1.10–1.21 and 0.56–0.64 mussels crab?1 d?1, respectively) for C. maenas. In all experiments, consumption rates of juvenile C. maenas were lower than or similar to those of the juvenile and adult indigenous species, suggesting that the potential predatory impact of juvenile C. maenas on Mytilus spp. may not be as significant as that of the adults of this non-indigenous species.  相似文献   

18.
Net photosynthesis under a range of natural light intensities was determined for three common macrophytes of the tidal freshwater Hudson River:Vallisneria americana Michx.,Potamogeton perfoliatus L., andMyriophyllum spicatum L. Light-saturated net photosynthetic rates did not differ among species, nor were there differences among species in the light intensity at which respiration balanced photosynthesis. The initial slope (α) of the photosynthesis-irradiance (P-I) curve was greater forV. americana than the other two species. As a result, maximum photosynthetic rates were reached inV. americana at significantly lower irradiances than those required to saturate photosynthesis inP. perfoliatus andM. spicatum. This characteristic would give this species a competitive advantage under conditions in which growth is limited by light availability. Macrophyte biomass distribution showed no clear correlation with depth.V. americana was the most abundant of the three species, both in frequency of occurrence and absolute biomass. The low irradiance required for the saturation of photosynthesis inV. americana may contribute to its predominance in the turbid Hudson River.  相似文献   

19.
The relationship between molluscan shell growth rate and skeletal δ18O and δ13C was investigated in a detailed field study for the scallop, Pecten maximus. Seasonal variation in shell growth rate was found to be a governing factor influencing shell δ18O and δ13C. At low shell growth rates, shell δ18O were more positive (of the order +0.4‰) and δ13C more negative (up to −2‰) as compared with predicted values for precipitation of inorganic calcite in isotopic equilibrium with seawater. The deviations in δ18O were hypothesized as reflecting possible differences in solution carbonate chemistry at the site of mineralization in the extrapallial fluid as compared with that of the external seawater medium. The deviations in shell δ13C were consistent with incorporation of isotopically depleted respiratory 13C (i.e., a metabolic effect). A trend toward more depleted shell δ18O and δ13C values occurred at higher shell growth rates, with negative δ18O values as compared with predicted equilibrium at shell growth rates above 0.13 mm per day. These simultaneous negative deviations in skeletal δ18O and δ13C were interpreted as resulting from a kinetic effect. The implications for environmental reconstruction from molluscan isotopic records are discussed in light of a model of isotopic behavior based on the findings of the study.  相似文献   

20.
The temporal variability in abundance and population structure of the gastropodChilina ovalis Sowerby was studied in the upper intertidal zone of Queule River estuary, south-central Chile (c. 40°S). Snails were collected monthly (September 1995–December 1997) from haphazardly-located quadrats (50×50 cm, n=5 each time), and counted and measured (shell height) in the laboratory. Water and sediment samples were collected at the same time to study the snail's habitat characteristics. Overall mean abundance was 115 individuals m?2 (SD=55). Monthly abundance estimates indicated a clear decrease during 1997. This decrease appeared to be related to the annual recruitment success of the species and at least partially to water temperature and sedimentological variability. Overall size range ofC. ovalis was 1.5–27.5 mm shell height. Growth varied seasonally with highest growth rates observed after recruitment (November–February). Slower growth continued throughout the austral winter months. Despite changes in abundance between 1996 and 1997, no differences were detected when population growth estimates were compared between years. A maximum longevity of approximately 4 yr was estimated from the growth curves of the cohorts, and a life cycle with more than one reproductive period is suggested.  相似文献   

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