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DEEPEST DISTRIBUTION OF ATLANTIC HERMATYPIC CORALS DISCOVERED IN THE BAHAMAS.
Get PDFHermatypic corals were collected in deep water with the JOHNSON-SEA -LINK submersibles on the western and southern margins of the Little Bahama Bank (LBB), northern Grand Bahama Bank (GBB), and San Salvador Island, Bahamas. The deepest distribution of hermatypic corals known in the Atlantic Ocean was found at San Salvador. Agaricia grahamae was collected from a firm attachment on the wall at 115m (observed to 119m), and Montastrea cavernosa from 11 3m. When compared with the other collection sites, maximum depth of coral growths was shallowest off western LBB (A. grahamae - 76m, M. cavernosa - 61m, Madracis decactis -75m) and northern GBB (Agaricia sp. - 76m) and was intermediate off southern LBB (M. decactis - 98m, M. cavernosa - 93m, A. grahamae -91m).
The variations in maximum depth distribution of the corals at these sites is probably due to geomorphology of the bank margins, sediment flux, and light penetration. The base of the vertical wall at the shelf edge is approximately 120, 100, 90 and 90m at San Salvador, southern and western LBB, and northern GBB sites, respectively. Below the wall at San Salvador is a steep (60-70*) limestone slope with little sediment accumulation. At the other sites, a rubble slope generally abuts the wall base, preventing deeper coral growth. Flux of shelf sediment onto the deeper reefs at San Salvador, which is a small island with narrow shelf, may be relatively low compared to GBB and LBB sites. Deepest coral growth at San Salvador was greatest on the eastern and southern margins where incident light would be greatest. Maximun photosynthetically active radiation (400 -700 rm) near the maximum depth of coral growth was 2.55 µΕ/m2/s (0.15 % of surface irradiance). Ranges of temperature (22.6-30.0 \u27 C) and conductivity (51.1 -57 µmho/cm2) were similar at all sites and probably not factors in variations of coral distribution
BARNACLE PLATE SEDIMENT PRODUCTION BY SHEEPSHEAD, THE INDIAN RIVER, FLORIDA.
Get PDFLiving barnacles eaten by sheepshead fishes results in the production of broken barnacle plate sediment. The yearly rate of production of broken barnacle plates is 4,9 kg m-2 and varies seasonally, with the largest mean flux in summer (22,5 g m? day-l) and the least in winter (1.9 g m-2 day ). The mean grain size mode of broken barnacle plates is positively correlated with the flux of broken barnacle plates, Experiments with exclusion and inclusion cages support the postulation that increases in flux and size of broken barnacle plates are caused by the feeding activity of larger sheepshead
NEARSHORE AND SHELF-EDGE OCULINA CORAL REEFS: THE EFFECTS OF UPWELLING ON CORAL GROWTH AND ON THE ASSOCIATED FAUNAL COMMUNITIES.
Get PDFColonies of Oculina varicosa were collected from nearshore, mid-shelf, and shelf-edge reefs off central eastern Florida. The shelf-edge reefs are inundated episodically throughout the year by upwelling of cool, nutrient rich water. On the inner shelf, cyclic seasonal factors predominate and upwelling intrudes only for a few weeks during the summer. Growth rates of the coral are significantly greater on the shelf-edge reefs than nearshore, even though at the shelf-edge temperatures are cooler and the coral lacks zooxanthellae. Species diversities of assemblages of decapods and mollusks associated with the coral are greater at the shelf-edge reef than at the mid- and inner-shelf reefs. It is suggested that the upwelling of nutrient rich water onto the shelf-edge Oculina reefs enhances the growth rate of the coral and facilitates the greater species diversity of the associated faunal communities compared to the inner-shelf reefs
EARLY LARVAL STAGES OF THE INDO-PACIFIC CORAL GALL-FORMING CRAB HAPALOCARCINUS MARSUPIALIS STIMPSON, 1859 (BRACHYURA, HAPALOCARCINIDAE) CULTURED IN THE LABORATORY.
Get PDFHapalocarcinus marsupialis, the type-species in the family Hapalocarcinidae,is one of at least 27 species in 8 genera of these remarkable little crabs that settle on living scleractinian corals and eventually become partially or completely imprisoned in the resultant gall produced by the host coral. Hapalocarcinus marsupialis is widely distributed and has been recorded from the eastern tropical Pacific (Garth & Hopkins, 1968) and throughout the Indo-west Pacific (Edmondson, 1933; Fize & Serene, 1957; Takeda & Tamura, 1979; among others). Although much is known about the general biology of the species (see e.g., Potts, 1915), only the first stage larvae have been described. Potts (1915), Edmondson (1933), Fize (1956) and Al-Kholy (1963) all provided brief descriptions or illustrations of first zoeal stages, most of which are inadequate to allow meaningful comparisons with larvae from other hapalocarcinids. Coupled with the inadequacies just noted is the fact that hapalocarcinid larvae are among the more difficult of brachyurans to culture in the laboratory, apparently requiring extended lengths of time in several zoeal stages in order to complete their development (see Fize, 1956; Scotto & Gore, 1981). In order to further clarify the systematic position of the adult members, an attempt was made to rear larvae of H. marsupialis through as many developmental stages as possible. Regrettably, only the first 2 zoeal stages of H. marsupialis were obtained. Accordingly, we provide herein complete descriptions of these stages and compare the larvae with those of Troglocarcinus corallicola Verrill, noting several morphological characters which may be important at both the generic and specific levels
SEDIMENT PRODUCED FROM ABRASION OF THE BRANCHING STONY CORAL OCULINA VARICOSA.
Get PDFSoft rubber tumbling barrels, some with screen windows, were used to simulate natural abrasion of coral branches. Tumbled for equal times, sealed barrels produced more sediment from coral branches than barrels with windows, and dead coral produced more sediment than live coral. Tumbled dead coral produced a gravel mode (2-4 mm) of fragmented barnacles and a sand mode (0.2 mm) of coral. Tumbled live coral produced similar results but lacked barnacles. Time series tests of 1-1000 minutes showed that closed barrels produced increasingly greater percentages of carbonate mud and increasingly finer sand grain-size modes. Tumbling barrels with screen windows yielded particles of unchanging size through the same intervals. Natural sediment with broken coral branches contained coral sand most abundantly between 0.125-0.250 mm, which is the same as produced by tumbling dead coral in barrels with screen windows. Strong grain-size modes at 0.2 mm produced by sonification and tumbling of live and dead coral in sealed and screen-window barrels support the Sorby Principle of skeletal breakdown
COMMUNITY COMPOSITION, STRUCTURE, AREAL AND TROPHIC RELATIONSHIPS OF DECAPODS ASSOCIATED WITH SHALLOW- AND DEEP-WATER OCULINA VARICOSA CORAL REEFS: STUDIES ON DECAPOD CRUSTACEA FROM THE INDIAN RIVER REGION OF FLORIDA, XXIV.
Get PDFDecapod crustaceans associated with living colonies of the scleractinian coral Oculina varicosa were sampled quantitatively for I year at 4 reef stations encompassing depths of 6, 27, 42, and 80 m off the central eastern Florida coast. A total of 42 samples of individual colonies yielded over 2,300 decapods in 15 families, 35 genera and 50 species, and was species-rich in xanthid and majid crabs (10, 6 spp., respectively), and alpheid shrimp (9 spp.). The community was predominantly anomuran with two species of hermit crabs (Pagurus carolinensis, P. piercei), a porcellanid crab (Megalobrachium soriatum) and a galatheid crab (Galathea rostrata) comprising four of the six most abundant species which accounted for 70% of all collected individuals.
Similarity between stations was low (8%) with only four species present at all stations. A gradient of species assemblages from shallow to deep stations corresponded with a similar gradient in environmental factors, with mean temperatures of24.6, 18.4, and 16.2°C recorded at 6, 42, and 80 rn, respectively. These temperatures and periodic cold-water summer upwelling affected species composition, with several species being lost at 6 m and never occurring at deeper stations. Wave surge and sedimentation, greatest at 6 rn, affected trophic partitioning, with a filter feeder (M. soriatum) numerically dominant here, whereas a detritivore (P. carolinensis) dominated deeper, less disturbed stations. The biotope also differed topographically among stations. At 6 m Oculina grew as thick-branched, wave-resistant colonies with encrusting bases and were widely scattered among a cover of algae and sponges on limestone ledges. At 80 m massive coral thickets formed banks composed solely of O. varicosa. Greater heterogeneity of the habitat surrounding the 6-m corals may be one reason this station had the highest species numbers (30) and species distribution (32% occurred nowhere but here).
Analyses of the effects of coral age on numbers of decapod species (S) and individuals (N) showed no significant correlation, whereas 48.8% of the variance in Sand 42.9% in N were related to the percentage of dead dry weight of the coral colony (r = .709, P \u3c .001; r = .667, P \u3c .001, respectively). Mean densities of individuals decreased with depth (44.47.5 N/100 g dead coral wt) and densities of most dominant species were positively correlated with size of the dead, rather than the live portion of the coral. Densities of the obligate commensals Domecia acanthophora and Troglocarcinus corallicola, however, were independent of coral size
IN SITU GROWTH RATES OF THE SCLERACTINIAN CORAL OCULINA VARICOSA OCCURRING WITH ZOOXANTHELLAE ON 6-M REEFS AND WITHOUT ON 80-M BANKS.
Get PDFRates of linear branch extension were determined for Oculina varicosa for one year on a nearshore, shallow-water reef (6 m] and on a shelf-edge. 0. varicosa coral bank (80 m) off central eastern Florida, U.S.A. Both site and season had a significant effect on growth with most of the variability due to the site factor. Linear branch growth was significantly greater at 80 m (x=16.1 mm/yr) than at 6 m (x= 11.3 mm/yr) although temperature was significantly lower at 80 m than 6 m (x=16.2, 24.6° C, respectively). The growth of the 6-m coral, possessing zooxanthellae, showed a negative response to high sedimentation rates which reduced light levels. Growth rates at both stations showed a positive response to water temperature and solar radiation and a negative response to current velocity
INSHORE OCCURRENCE AND NUPTIAL BEHAVIOR OF THE ROUGHTAIL STINGRAY DASYATIS CENTROURA (DASYATIDAE), ON THE CONTINENTAL SHELF, EAST CENTRAL FLORIDA.
Get PDFAt 0935 on November 30, 1978, a male and female roughtail stingray Dasyatis centroura were observed for a period of 10 minutes in an apparent courtship or mating ritual. This observation, using the JOHNSON-SEA-L1NK research submersible (J-S-L1, Dive Number 615), took place near the base of a deep-water, Oculina varicosa coral bank (Reed, 1980) 27 km east of Ft. Pierce, Florida at 27° 32. 8\u27N, 79° 58.8\u27W and at a depth of 80 m. The area was a flat sand bottom 20-30 m from the base of the 17 m high Oculina coral bank. A few pieces of limestone with Oculina rubble protruded through the green silty-sand, and patches of the gorgonian Titanideum frauenfeldii and the antipatharian Cirrhipathes desbonii covered the bottom. Visibility was 6-8 m, current 5 ern/sec from the south, and the temperature was 20.4°C. An externally mounted Benthose camera with 200 Ektachrome film and a hand held 35 mm single lens reflex camera were used to record the event. Thirty-five sequential photographs were taken of these rays
DISTRIBUTION AND STRUCTURE OF DEEP-WATER OCULINA VARICOSA CORAL REEFS OFF CENTRAL EASTERN FLORIDA.
Get PDFData on the distribution and growth-form of the scleractinian Oculina varicusa were compiled from 135 submersible dives with the JOHNSON-SEA-L1NK submersibles and 57 dredge and trawl records by the R/V GOSNOLD and R/V AQUARIUS. A deep-water form of O. varicosa, lacking zooxanthellae, was found in depths of 50 to 100 m off central eastern Florida. These colonies are arborescent with highly anastomosed, irregular dendritic branches. Over 50 sites were located at which living colonies of O. varicosa from 0.25 to 2 m diameter occur either singly or as sparsely scattered groups. Nine areas were found with massive thickets of contiguous colonies up to 2 m in height. Extensive banks of Oculina thickets were found at five locations. The banks have a relief of 17 to 24 m and steep slopes of 30-45°, especially on the south side which faces into the Florida Current. The structure of these thickets and banks is very similar to deep-water Lophelia prolifera banks. Temperatures on the Oculina banks ranged from 7.5 to 26.5°C and had a yearly mean of 15°C
BENTHIC MACROFAUNAL ASSOCIATIONS IN LAKE WORTH, FLORIDA, AND THEIR USE AS INDICATORS OF WATER QUALITY.
No full textBimonthly benthic samples (April, 1972 to March, 1973) taken at eleven stations provide quantitative reference data on the benthic macrofaunal communities of Lake Worth in Palm Beach County, Florida. Distribution and structure in relation to sediment types and sources of pollution are discussed. One hundred seventy-one taxa were identified. The five top-ranked species were the bivalve Mulinia lateralis; the polychaetes Spiochaetopterus oculatus, Paraprionospio pinnata, and Glycinde solitaria; and the amphipod Cerapus sp. Stations were grouped as sand, silty-sand, mud, and outfall stations based on similarity of faunal composition and sediment type. The sand and silty-sand stations had the highest diversity (H\u27) and species richness (spp/180) values. The mud and outfall stations had low H\u27 and spp/180 values which were similar to values reported for pollution-stressed areas in other studies. The outfall station was dominated by the pollution-tolerant polychaete Capitella capitata