ALBERT

Notes: SUMMARY. 1. The annual cycle of the freshwater sponge, Anheteromeyenia ryderi, was studied in a seepage pond in Connecticut. The adult form of the sponge persisted throughout the year, although some specimens at the edge of the pond degenerated by late summer. During the middle of the winter, adult sponges had a simplified tissue morphology with reduced numbers of flagellated chambers.2. Gemmules of A. ryderi were also present during all seasons. Gemmule germination occurred during the spring, and some specimens produced new gemmules by late spring.3. The gemmules of A. ryderi underwent a protracted diapause which was broken under both natural and laboratory conditions by several months exposure to low temperatures (≤5°C).4. The gemmules of Heteromeyenia tubisperma were also shown to undergo diapause, but in this case diapause was broken by a relatively short cold treatment (1 month).

Notes: In 1980 the State of Connecticut began a tidal marsh restoration program targeting systems degraded by tidal restrictions and impoundments. Such marshes become dominated by common reed grass (Phragmites australis) and cattail (Typha angustifolia and T. latifolia), with little ecological connection to Long Island Sound. The management and scientific hypothesis was that returning tidal action, reconnecting marshes to Long Island Sound, would set these systems on a recovery trajectory. Specific restoration targets (i.e., pre-disturbance conditions or particular reference marshes) were considered unrealistic. However, it was expected that with time restored tides would return ecological functions and attributes characteristic of fully functioning tidal salt marshes. Here we report results of this program at nine separate sites within six marsh systems along 110 km of Long Island Sound shoreline, with restoration times of 5 to 21 years. Biotic parameters assessed include vegetation, macroinvertebrates, and use by fish and birds. Abiotic factors studied were soil salinity, elevation and tidal flooding, and soil water table depth. Sites fell into two categories of vegetation recovery: slow, ca. 0.5%, or fast, more than 5% of total area per year. Although total cover and frequency of salt marsh angiosperms was positively related to soil salinity, and reed grass stand parameters negatively so, fast versus slow recovery rates could not be attributed to salinity. Instead, rates appear to reflect differences in tidal flooding. Rapid recovery was characterized by lower elevations, greater hydroperiods, and higher soil water tables. Recovery of other biotic attributes and functions does not necessarily parallel those for vegetation. At the longest studied system (rapid vegetation recovery) the high marsh snail Melampus bidentatus took two decades to reach densities comparable with a nearby reference marsh, whereas the amphipod Orchestia grillus was well established on a slow-recovery marsh, reed grass dominated after 9 years. Typical fish species assemblages were found in restoration site creeks and ditches within 5 years. Gut contents of fish in ditches and on the high marsh suggest that use of restored marsh as foraging areas may require up to 15 years to reach equivalence with reference sites. Bird species that specialize in salt marshes require appropriate vegetation; on the oldest restoration site, breeding populations comparable with reference marshland had become established after 15 years. Use of restoration sites by birds considered marsh generalists was initially high and was still nearly twice that of reference areas even after 20 years. Herons, egrets, and migratory shorebirds used restoration areas extensively. These results support our prediction that returning tides will set degraded marshes on trajectories that can bring essentially full restoration of ecological functions. This can occur within two decades, although reduced tidal action can delay restoration of some functions. With this success, Connecticut's Department of Environmental Protection established a dedicated Wetland Restoration Unit. As of 1999 tides have been restored at 57 separate sites along the Connecticut coast.

Notes: Abstract Macroinvertebrates were examined on an impounded valley marsh in Stonington, Connecticut, that has changed from aTypha-dominated system to one with typical salt-marsh vegetation during 13 years following the reintroduction of tidal exchange. Animal populations on this restored impounded marsh were evaluated by comparing them with populations on a nearby unimpounded valley marsh of roughly the same size. Populations of the high marsh snail,Melampus bidentatus Say, were quantitatively sampled along transects that extended from the water-marsh edge to the upland; those of the ribbed mussel,Geukensia demissa Dillwyn, were sampled in low marsh areas on transects along the banks of creeks and mosquito ditches. The occurrence of other marsh invertebrates also was documented, but their abundance was not measured. The mean density ofMelampus was 332±39.6 SE/m2 on the restored impounded marsh and 712±56.0 SE/m2 on the unimpounded marsh. However, since snails were larger on the restored impounded marsh, the difference in snail biomass was less pronounced than the difference in snail density. MeanMelampus biomass was 4.96±0.52 SE g dry wt/m2 on the restored impounded marsh and 6.96±0.52 SE g dry wt/m2 on the unimpounded marsh. On the two marshes, snail density and biomass varied in relation to plant cover and other factors. The density and biomass ofGeukensia at the edge of the marsh were comparable on the restored impounded and unimpounded marshes. Mean mussel densities ranged from 80 to 240/m2 and mean mussel biomass varied from 24.8–64.8 g dry wt/m2 in different low marsh areas. In contrast, below the impoundment dike, meanGeukensia density was 1100±96.4 SE/m2 and meanGeukensia biomass was 303.6±33.28 SE g dry wt/m2. A consideration of all available evidence leads to the conclusion that the impounded marsh is in an advanced phase of restoration.

Notes: Abstract A survey of Connecticut lakes and rivers revealed the presence of 7 species of freshwater sponge: Spongilla lacustris, Ephydatia muelleri, Eunapius fragilis, Anheteromeyenia ryderi, A. argyrosperma, Corvomeyenia carolinensis, and Corvospongilla novaeterrae in order of decreasing frequency of occurrence. Corvomeyenia carolinensis has not been reported previously beyond its type locality in South Carolina. In addition, microscleres of Spongilla lacustris, Anheteromeyenia-like megascleres, Ephydatia muelleri-like megascleres, and smooth megascleres (amphioxeas), which could not be assigned to a particular species, were found in surface sediments from lake cores. Spongilla lacustris inhabiting small rivers produced brown, thick-capsuled gemmules during the summer and yellow, thin-capsuled gemmules during the fall. The thick-capsuled gemmules, but not the thin-capsuled gemmules, are tolerant of desiccation; and populations of Spongilla lacustris and Ephydatia muelleri survived severe drying of their habitats during the summer.

Notes: Abstract A survey of 28 Connecticut water bodies for spicular remainsoffreshwater sponges preserved in lacustrine sediments revealed14species representing 10 genera. Sediments were examined atfivelevels (ca 1991, ca 1970, ca 1934, ca 1890, ca ≤ 1875)todocument changes in species composition, distribution, andabundance. Five species were recorded statewide in all fivegeologic regions: Spongilla lacustris, Heteromeyeniatubisperma, Anheteromeyenia ryderi, Eunapius fragilis, andEphydatia muelleri. Spongilla lacustris was the mostcommonand widely distributed species. Factors that may havecontributedto the observed distribution of the spongillids in Connecticutareregional differences in lake water chemistries, individualspeciestolerances, and differences in extent of dispersal of variousspecies. Most of the more abundant species are widelydistributedwith respect to water quality parameters. Anheteromeyeniaargyrosperma, Duosclera mackayi and Trochospongillapennsylvanica appear to be restricted to waters exhibitingthelower ranges for conductivity, alkalinity and calcium content.Ingeneral, a greater number of spicules was found in bottomsedimentsof the surveyed lakes as compared with the surface sediments.Oftenthis was correlated with increased sediment accumulation ratesinmore recent periods. When this fact is taken into account, itappears that populations of a number of sponge species haveremained relatively constant in many of the lakes over thepastcentury. However, in some lakes exhibiting lower or onlyslightlyhigher sediment accumulation rates at the surface, fewerspiculeswere also found in more recent sediments, suggesting an actualdecline in sponge population sizes. Changes in abundance overthelast 100 years may be related to changes in land use practicesinsurrounding watersheds and the associated changes in waterchemistries.

Notes: Abstract Most green gemmules of Spongilla lacustris survived enclosure in ice at −20 °C for up to 30 days; however, their rate of germination at 20 °C was less rapid than that of control gemmules. The length of time spent at low temperature had little effect on gemmule survival. In contrast, repeated cooling to −20 °C and warming to 4 °C led to a progressive decline in gemmule viability. These results indicate that cold injury occurs primarily during transitions between high and low temperatures.

Notes: Abstract Examination of spicules from a living sponge confirmed thepresenceof Corvomeyenia carolinensis in Mohawk Pond, LitchfieldCounty, Connecticut. Until recently this species had only beenreported from one locality in South Carolina. Based uponspiculeobservations in dated sediment samples this species appears tohaveexisted within Mohawk Pond throughout the past 100+years.

Notes: Abstract Gemmules of the freshwater sponge, Eunapius fragilis (Leidy), survived exposure to 30 ppt natural sea water at 20 °C for up to 27 days and to 37 ppt Instant Ocean sea water for up to at least 9 days. This high salinity tolerance may have made possible the dispersal of the sponge on the hulls of ocean-going ships that frequented freshwater ports. The gemmules also survived 9-day exposures to 5% NaCl, 20% NaCl and some artificial sea waters containing only a few of the major ions. All of these solutions inhibited germination of the gemmules during the period of exposure, and treatment with 30 ppt natural sea water, 37 ppt Instant Ocean sea water, 20% NaCl and a solution containing Na+, Cl− and SO inf4 sup2− had a persisting inhibitory effect on gemmule germination after the gemmules were returned to pond water at 20 °C. Many of the gemmules that did not germinate under favorable conditions following treatment could be stimulated to germinate after they were chilled at 4 °C for 4 or more months. Such gemmule inhibition mimics natural diapause which also is broken by exposure to low temperature.

Notes: Abstract Gemmules of Anheteromeyenia ryderi survived 24 h exposure to air temperatures as low as −20 °C under laboratory conditions. Drying the gemmules of A. ryderi at 5 °C under laboratory conditions resulted in a reduced viability and a slower germination rate following rehydration compared with undried control gemmules. Only 25% of the gemmules germinated after drying for one month. Up to 25% of the gemmules of A. ryderi that were tested survived aerial exposure from early November to early April when a pond in Connecticut inhabited by this sponge was drained. During this period air temperatures dropped to as low as −16 °C. Continued aerial exposure of the gemmules during the summer resulted in nearly complete gemmule mortality.

Notes: Oogenesis and embryonic development in the marine sponge, Haliclona ecbasis, were studied using standard histological procedures.When the oocytes reach a diameter of about 30 μ, nurse cells begin to aggregate around them. Then when the oocytes are about 36 μ in diameter, they begin to engulf the associated nurse cells. Whole nurse cells are engulfed; and although the nucleus of the nurse cells disappears either as or soon after the cells are engulfed, the cytoplasm remains essentially unchanged. The accumulation of these cells within the oocytes most of the cytoplasm is nurse cell cytoplasm.During cleavage of the egg, the engulfed nurse cells are gradually fragmented, but otherwise appear unchanged. At the same time the cytoplasm of the nurse cells is progressively incorporated into that of the blastomeres by what appears to be fusion process. When the latter process is complete, the embryo develops into a typical parenchymula larva.