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Full-Text Articles in Life Sciences
Color Image-Analyzed Fluorescence Microscopy: A New Tool For Marine Microbial Ecology, Ml Sieracki, Cl Viles
Color Image-Analyzed Fluorescence Microscopy: A New Tool For Marine Microbial Ecology, Ml Sieracki, Cl Viles
VIMS Articles
BACTERIA, cyanobacteria, protozoa and small eukaryotic phytoplankton are now known to be funda- mental components of marine planktonic ecosystems (Azam et al., 1983; Sieburth, 1984). These organisms have high potential growth rates, are efficient convert- ers of material and energy, and usually constitute most of the plankton biomass (Davis et al., 1985; Fuhrman et al., 1989). Their different trophic levels are often closely coupled. These characteristics require that experimental and sampling designs for studying the microbial populations incorporate appropriate (i.e., small) temporal and spatial scales. The corollary to this is that large numbers of samples must be taken. If these …
Small-Scale Organism Distributions And Patterns Of Species Diversity: Evidence For Positive Interactions In An Estuarine Benthic Community, Linda C. Schaffner
Small-Scale Organism Distributions And Patterns Of Species Diversity: Evidence For Positive Interactions In An Estuarine Benthic Community, Linda C. Schaffner
VIMS Articles
No abstract provided.
Utilization Of Marsh And Seagrass Habitats By Early Stages Of Callinectes-Aapidus - A Latitudinal Perspective, R J. Orth, J Van Montfrans
Utilization Of Marsh And Seagrass Habitats By Early Stages Of Callinectes-Aapidus - A Latitudinal Perspective, R J. Orth, J Van Montfrans
VIMS Articles
Seagrass beds and marshes have been identified as important nurseries for the blue crab, Callinectes sapidus. This nursery paradigm is based on blue crab abundance data from trawl, seine and drop-net sampling that has revealed greater abundances in these habitats than in adjacent unvegetated areas. Recently, more quantitative and intensive sampling in seagrass beds and marshes over broad latitudinal scales, combined with manipulative experiments, indicate that the same habitat may vary in utilization on regional scales. Mechanisms accounting for enhanced abundances in these nursery habitats have not been elucidated from a latitudinal perspective. Regional comparisons of blue crab catch data …
Utilization Of A Seagrass Meadow And Tidal Marsh Creek By Blue Crabs Callinectes-Sapidus Ii. Spatial And Temporal Patterns Of Molting, Ch Ryer, J Van Montfrans, Rj Orth
Utilization Of A Seagrass Meadow And Tidal Marsh Creek By Blue Crabs Callinectes-Sapidus Ii. Spatial And Temporal Patterns Of Molting, Ch Ryer, J Van Montfrans, Rj Orth
VIMS Articles
Blue crabs were collected weekly from a lower Chesapeake Bay seagrass meadow and adjacent tidal marsh creek over 2 months (July-August 1987) and molt staged. Molting activity, determined from a total of I ,220 crabs, was greater in the grassbed than in the marsh creek, and greater for small crabs and females. The difference between the two habitats in molting activity decreased from the first to the second month of sampling, possibly in response to seasonal decline in seagrass biomass. The proportion of small (<70 mm) females in both habitats was greatest on full moons. There was a lunar rhythm of molting activity by large crabs (2:70 mm), with peak molting activity on fuIl moons. SmaIl crabs demonstrated a similar, but nonsignificant rhythm of molting. We suggest that blue crabs approaching ecdysis aggregate in seagrass meadows, taking advantage of the refuge from predation that this structurally complex habitat affords. Lunar rhythmicity of molting activity may further reduce predation mortality through a dilution effect.
Molting In The Mature Female Blue-Crab, Callinectes-Sapidus Rathbun, Kirk J. Havens, Jr Mcconaugha
Molting In The Mature Female Blue-Crab, Callinectes-Sapidus Rathbun, Kirk J. Havens, Jr Mcconaugha
VIMS Articles
The present study examined the hypothesis that mature female blue crabs, Callinectes sapidus, do not enter a terminal anecdysis. Induced molting via eyestalk ablation, size frequency distributions, gonad development and limb regeneration indices from field collected animals are used as indicators of potential post maturity molts. Eyestalk ablation of 15mature females resulted in ecdysis in II individuals approximately 51 days (standard error = 0.64) after ablation, indicating a physiological ability of mature females to complete ecdysis. Analysis of size frequency distributions from catch data indicated two distinct shifts from smaller to larger females, one in early spring and a second …
Daily, Monthly And Annual Settlement-Patterns By Callinectes-Sapidus And Neopanope-Sayi Megalopae On Artificial Collectors Deployed In The York River, Virginia - 1985-1988, J Van Montfrans, Ca Peery, R J. Orth
Daily, Monthly And Annual Settlement-Patterns By Callinectes-Sapidus And Neopanope-Sayi Megalopae On Artificial Collectors Deployed In The York River, Virginia - 1985-1988, J Van Montfrans, Ca Peery, R J. Orth
VIMS Articles
Daily, monthly and annual settlement of dominant brachyuran megalopae on six replicate artificial settlement substrates (collectors) was examined at one site in the York River, Virginia, from mid-July or early August to early December during 1985-1988. Callinectes sapidus Rathbun, an exported estuarine species, and Neopanope sayi (Smith), a retained estuarine species, were the numerically dominant colonizers of collectors. C. sapidus settlement was highly episodic (l-3-day duration) and significantly associated with the full moon period (lunar day 15-22). The temporal mean of settlement for C. sapidus each year fell within a 12-day period (24 September-6 October) over the 4 years. C. …
Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia, Ej Olmi, J Van Montfrans, Rn Lipcius, R J. Orth, Pw Sadler
Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia, Ej Olmi, J Van Montfrans, Rn Lipcius, R J. Orth, Pw Sadler
VIMS Articles
Blue crab, Callinectes sapidus, megalopae and juveniles were sampled in the plankton and on natural (grassbeds) and artificial settlement substrates (collectors) at two sites in each of two areas of a lower Chesapeake Bay tributary (York River, Virginia) to examine spatial variability in blue crab recruitment. Spatial patterns of abundance were not consistent across habitats (plankton, artificial collectors and grassbeds) or time. Densities of planktonic megalopae were homogeneous at 1-2 m (within site) but varied at spatial scales of hundreds of meters (between sites) and kilometers (between areas). Settled megalopae were distributed unevenly within and between sites, but their abundance …