Fine Sand Substrate Research Articles

Experimental study on spread radius and burning rate of spill fires on a fine sand substrate

Experimental study on spread radius and burning rate of spill fires on a fine sand substrate

Application of compost in the different of pen culture substrates type for the intensification of sea cucumber, Holothuria scabra (Jaeger 1883) culture

Intensification of aquaculture is directed at the effort to increase productivity by carrying capacity of production factors. This study was conducted to evaluate the growth performance of Holothuria scabra cultured intensively through the application of compost fertilizer. H. scabra were reared for 90 days (20 individuals/m2 of density), using a pen culture method on the three different substrates, namely fine sand, seagrass mud, and coarse sand, where each treatment was made as four replicates. The amount of compost used for the type of each substrate was the same. The results showed that applying compost in sea cucumbers culture using the pen culture method was proven to be effective in increasing the growth performance of sea cucumbers H. scabra, with the weight gain, growth rate, and survival, respectively, ie: 49.10±1.62 g; 1.26±0.03% g/day and 90.00% on seagrass mud substrate; 46.00±6.92 g; 1.23±0.11% g/day and 89.00% on a fine sand substrate and the lowest is 42.05±g; 1.13±0.08% g/day and 87.50% were found on a coarse sand substrate. The growth response was not significantly different between the three substrate types (Duncan’s test, p>0.05), indicating that the availability of nutrient sources in substrates is one of the key factors for the intensification of H. scabra culture.

The success of seagrass restoration using Enhalus acoroides seeds is correlated with substrate and hydrodynamic conditions

The extent of seagrass areas and their associated ecosystem functions and services have been declining due to many factors. Seagrass restoration is important to mitigate such declines. Seagrass restoration using seeds can be a viable method due to the high seed availability of some seagrass species and could enhance seagrass resilience to climate change stress. However, this method sometimes has low success rates due to high seed predation and seeds being washed away by wave action or substrate movement. The research was conducted to compare the settlement of Enhalus acoroides seeds and the establishment of seedlings on different sediment types (fine sand, coarse sand, and hard substrate with rubble) combined with different wave exposure levels (high and moderate). This is the first study to observe seed survival and seedling establishment of the tropical seagrass E. acoroides in the wild. On average, 64% of seeds dispersed on fine sand substrate at a moderate exposure site survived and developed into established seedlings by the end of the 40 days observation period, but the survival of seeds dispersed on coarse sand at high exposure and hard substrate at moderate exposure only remained above 50% for up to 3 days, and had declined to 2% and 1.4%, respectively, by day 40. Six years later, surviving E. acoroides sample from the coarse sand and hard substrate both had well-developed rhizomes but fewer roots than the plant from the fine sand site, these rhizome and roots characteristics were likely adaptations to increase anchoring capacity in the specific site. The results indicate that Enhalus seed settlement and seedling establishment can readily occur at sites with fine sand substrate and lower wave exposure; however, additional measures may be required at more exposed sites with mobile or hard substrates until seedlings become established.

Redescription, paleogeography, and experimental paleoecology of the Silurian phyllocaridGonatocaris

AbstractGonatocaris decora(Clarke, 1901) is an unusual, highly ornamented Silurian phyllocarid from the Pittsford Shale Member of the Vernon Formation, Salina Group of New York, that has been allied withEmmelezoein the past due to the possession of an ‘optic tubercle.’ The systematic positions ofGonatocarisandEmmelezoehave been difficult to assess due to the lack of complete remains, attributions based on spurious characters, and missing and unfigured specimens. Relatively recent collections ofGonatocaris decora, along with a relocation of the original type material ofEmmelezoe, have allowed a reexamination of all relevant genera and a more robust systematic placement forG. decora. Characters of generic importance forGonatocarisinclude a greatly elongated abdomen; an acute angle of the ventral carapace margin separating distinct anteroventral and posteroventral margins from each other; and distinctive, multiscale horizontal ridge-like ornament of the carapace valves. Growth was found to be isometric. Experimental work done using a model of the scale-like ornament and multiple grain sizes of substrate indicates that cuticle ornament may have served to increase friction between the animal and a fine sand substrate, although resistance to predation is the currently favored hypothesis. BecauseGonatocarisspecies are currently known only from the eastern margin of Laurentia and northern South China, it is likely that this genus was nektonic. Accumulations of similarly sized carapaces and other disarticulated sclerites in shallow-water settings may indicate spawning events following molting en masse.

Distribution of Benthic Foraminifera off Kelantan, Peninsular Malaysia, South China Sea

Abstract We investigated the distribution of modern benthic foraminifera from Kelantan waters in the western part of the Sunda Shelf, South China Sea. Twenty-nine benthic foraminiferal species were identified from seven samples collected along a ∼250 km-long transect perpendicular to the Kelantan coastline. Calcareous hyaline species made up 57% of the overall assemblages collected in the study area, followed by calcareous porcelaneous (23%) and agglutinated (20%) species. Cluster analysis recognised two distinctive groups. Group A represented the shallow inner-shelf area (19–35 m water depth) with a coarse sand-dominated substrate where Amphistegina papillosa (13.37%) and Assilina ammonoides (11.04%) were highly abundant. Group A had lowest diversity with no agglutinated species. Group B, occurred at 40–60 m water depth, had higher foraminiferal diversity and was characterised by a very fine sand substrate. The foraminiferal assemblages here were dominated by calcareous hyaline species in group B followed by calcareous porcelaneous and agglutinated species. Group B was characterised by Assilina ammoinodes (11.04%), Heterolepa dutemplei (10.29%), and Discorbinella bertheloti (10.03%). The dominant agglutinated species in Group B were Textularia agglutinans (4.93%) and Cylindroclavulina bradyi (3.55%). Shallow-water species, such as Amphistegina spp., were absent from Group B. Our study shows that the distribution of benthic foraminiferal assemblages from the western Sunda shelf off Kelantan, is closely associated with changes in seafloor sediment, distance from the shore, and water depth.

4TEFFECTS OF GRAIN SIZE, ROUGHNESS, AND HARDNESS OF SEA FLOOR ON BACK SCATTERING VALUE BASED ON HYDROACOUSTIC DETECTION

3TBased on results of detection hydroacoustic, backscattering value from the first reflection (E-1) can describe the roughness and from the second reflections (E-2) can describe the hardness of sea floor. The objective of this study was to analyze the relationship between grain size, roughness and hardness with backscattering values using the hydroacoustic method. The results showed that the roughness, hardness, and diameter size fraction of fine sand substrate were greater than that of muddy sand substrate. The backscattering values of very fine sand substrate were also greater than that of muddy sand substrate.Keywords: Hydroacoustic, bottom, backscattering

4TEFFECTS OF GRAIN SIZE, ROUGHNESS, AND HARDNESS OF SEA FLOOR ON BACK SCATTERING VALUE BASED ON HYDROACOUSTIC DETECTION

<p>3TBased on results of detection hydroacoustic, backscattering value from the first reflection (E-1) can describe the roughness and from the second reflections (E-2) can describe the hardness of sea floor. The objective of this study was to analyze the relationship between grain size, roughness and hardness with backscattering values using the hydroacoustic method. The results showed that the roughness, hardness, and diameter size fraction of fine sand substrate were greater than that of muddy sand substrate. The backscattering values of very fine sand substrate were also greater than that of muddy sand substrate.</p><p>Keywords: Hydroacoustic, bottom, backscattering</p>

Protodrilidae (Annelida: Polychaeta) from the Hawaiian Islands and Comparison with Specimens from French Polynesia

Abstract: Three species of Protodrilidae were collected from the islands of O'ahu and Ni'ihau in the Hawaiian chain, including specimens closely resembling Parenterodrilus taenioides (Jouin, 1979), described from Mo'orea (French Polynesia). Others are probably an undescribed species of Parenterodrilus that was found in fine sand substrate collected off Wai'anae, O'ahu. A third species, Protodrilus albicans Jouin, 1970, described from Banyuls-sur-Mer (Mediterranean $ea) and recorded from Mo'orea and Tahiti as well, was also collected from O'ahu. Depths and habitat characteristics are given for these new records to the Hawaiian fauna. It is suggested that the wide geographical distribution of the different “cosmopolitan species” of Protodrilidae is related both to the dispersal by free-swimming larvae and to the ancient origin of this interstitial fauna.

Effects of Slope, Substrate, and Temperature on the Locomotion of the Ornate Box Turtle, Terrapene ornata

Ornate box turtles, from the Sand Hills of Nebraska, live in a habitat characterized by slopes, a fine sand substrate, and temperatures that can vary greatly, both diurnally and seasonally. We examined the locomotor responses of these turtles to slope, substrate, and temperature. Only 25% of the turtles could successfully walk on slopes as steep as −40°. They were better at walking upslope, but their speed progressively decreased as slope increased. As grade increased, they primarily adjusted stride frequency on upslopes but stride length on downslopes. Turtles appear to be much more affected by slopes than are lizards. Speed was significantly reduced on sand substrates in comparison to Styrofoam, and this was primarily because of a reduction in effective stride length. Speed increased with increasing temperature from 20 to 35 C, almost entirely resulting from an increase in stride frequency; however, the Q10 for locomotor performance was low. Turtle speeds in the field averaged 0.05 m/s, and, although there was a tendency for higher speeds at higher operative environmental temperatures, this was not statistically significant. Within their natural Sand Hill habitat, these turtles are often active under conditions of slope, substrate, and temperature that are suboptimal for locomotion. However, locomotor performance is not adversely affected to any appreciable degree by the potential constraints of their habitat.

Population differentiation of the Stellaria longipes complex within Saskatchewan's Athabasca sand dunes

Stellaria arenicola, a recent derivative within the S. longipes complex, is an endemic of the Athabasca sand dunes. Analysis of 11 morphological characters on 40 genets showed that both the endemic and parental (S. longipes) species are present within the Thomson Bay dune field and that the two forms are distinct. Individuals of S. arenicola were distinguished by only a few characters, typically, large yellow capsules with reflexed teeth and yellowish leaf and stem pigmentation. The endemic also exhibited a higher sexual reproductive output. Many characteristics of vegetative morphology showed plasticity in both species, but the two remained distinct when grown in a common garden. On the sand dunes S. longipes is restricted to beach dunes bordering Lake Athabasca while S. arenicola is predominant on the active dune field inland. The two dune systems represented environmentally distinct microhabitats. The active inner dunes were characterized by an unstable, fine sand substrate and intense insolation. Field reciprocal transplants showed S. longipes was selected against in the inner dune habitat, while S. arenicola performed relatively well on the beach. Stellaria arenicola possibly arose in the active sand dune habitat as a result of selection pressure and genetic isolation.

Gray Whale and Walrus Feeding Excavation on the Bering Shelf, Alaska

ABSTRACT Sidescan sonar has been used to delineate benthic feeding structures of the California gray whale (Eschrichtius robustus) and Pacific walrus (Odobenus rosmarus divergens) on the northeastern Bering Shelf. The gray whales (average mouth length, 2.0 m), when suction feeding on infaunal amphipods, create shallow pits in the sea floor, typically 2.5 m 1.5 m 10 cm deep, which are distinct and mappable on sidescan sonographs. Similarly, walrus, when foraging for shallow clams, create long, linear feeding furrows that average 47 0.4 0.1 m (length-width-depth). The distr bution of the whale pits over 22,000 km2 of the Bering Shelf closely matches 1) sightings of feeding whales identified by mud plumes; 2) the distribution of ampeliscid amphipods, the gray whale's main prey; and 3) the distribution of a transgressive inner-shelf fine sand that serves as a substrate for the amphipods. The walrus' furrows are recognized over 6,600 km2 of variable muddier or coarser-grained substrate with clam-rich benthic communities that surround the fine sand substrate of whale feeding areas. The whale feeding pits are commonly enlarged and oriented by seasonal storm-related scour. Nonenlarged pits (less than 5.3 m2 in area) form a discrete statistical population that we define as fresh. We estimate that a minimum of 5.6 percent (1,200 km2) of the feeding area of the northeastern Bering Shelf (22,000 km2) was covered by fresh pits made by whales during the 1980 feeding season. Assuming that the average pit depth is 10 cm, a minimum of 120 106 m3 (172 106 metric tons) of sediment, equivalent to about three times the yearly sediment load of the Yukon River, is excavated and injected into the water c lumn by as many as 16,000 gray whales feeding in northeastern Bering Sea each season. As a result of 1) sediment resuspension by whales, 2) average current speeds of 10.7 cm/s northward during the feeding season, and 3) enhanced post-feeding current scour because of bottom roughening, the following occur: the majority of the clay fraction (4.3 106 metric tons) of resuspended sediment is advected to the Chukchi Sea each year; sand gradually is transported northward and fills old feeding pits; modern mud does not accumulate in this region; and the whale-disturbed sand lacks physical sedimentary structures and matrix mud. Walrus feeding features are smaller, formed in higher-energy environments, and modified more rapidly than whale feeding pits. The amount of sediment reworking by walrus feeding may nearly equal that of whale feeding, but this cannot be quantified accurately.

Side-Scan Sonar Assessment of Gray Whale Feeding in the Bering Sea

Side-scan sonar was used to map and measure feeding pits of the California gray whale over 22,000 square kilometers of the northeastern Bering Sea floor. The distribution of pits, feeding whales, ampeliscid amphipods (whale prey), and a fine-sand substrate bearing the amphipods were all closely correlated. The central Chirikov Basin and nearshore areas of Saint Lawrence Island supply at least 6.5 percent of the total gray whale food resource in summer. While feeding, the whales resuspend at least 1.2 x 10(8) cubic meters of sediment annually; this significantly affects the geology and biology of the region.

Population dynamics and reproductive cycle of Pholo� minuta (Polychaeta: Sigalionidae) in Galway Bay

Pholoe minuta (Fabricius) is a prominent member of the Amphiura filiformis (O.F. Muller) subcommunity in Galway Bay, Ireland. The aim of the present investigation was to study the population dynamics and reproductive cycle of P. minuta in this area. Monthly sampling over a 2 yr period (November 1978–October 1980), at a permanent station (18 m) with a fine sand substrate, revealed a mean density of 96 individuals per 0.1 m2. The width of the fifth elytron was correlated with total body length and was used as a basis for analysing population structure. Four distinct year classes were evident and estimates of recruitment levels and growth rates were calculated. P. minuta is polytelic and reproduces for the first time when approaching 3 yr of age. Spawning occurred in March—April and appeared to be associated with a seasonal low in bottom-water temperature.