Notes on the ecology of Astropecten aranciacus

In a shallow coastal region of Sardinia (European Mediterranean Sea) the activity pattern and migration habits of the sea star Astropecten aranciacus were studied by means of SCUBA diving. The species is nocturanl, with two modes of abundance. Different size classes revealed different activity schedules. A sample taken at dusk consisted of comparatively large-sized sea stars, while another sample taken at night included small-sized sea stars with the larger individuals. By tagging the sea stars with numbers, their locomotory activity during the night, as well as day, was investigated.     

Pollution assessment of the lower basin of Lakes Kainji/Jebba, Nigeria: heavy metal status of the waters, sediments and fishes

The objective of this investigation was to examine the heavy metal status of the lower basin of Kainji dam (used for hydroelectricity generation), which includes Lakes Kainji/Jebba, Nigeria, and the potential for human exposure to heavy metals from eating fish caught in the lakes. Water, sediments and fish were sampled from the lakes and evaluated for As, Cu, Co, Cr, Fe, Hg, Mn, Ni, Pb, Sb, Ti, V and Zn using the EDXRF technique. Fe and Mn were found to be present at high mean concentrations in the water (13 and 9 μg L^-1), sediment (7092 and 376 μg g^-1) and fish (11.4 and 4.6 μg g^-1) samples. Sb (3.2 μg L^-1), Ti (4.1 μg L^-1), Cr (2.2 μg L^-1), Co (1.2 μg L^-1), Cu (1.3 μg L^-1) and Pb (1.2 μg L^-1) in the water samples and Sb (29 μg g^-1), Ti (27 μg g^-1), V (27 μg g^-1), Cr (27 μg g^-1), Co (40 μg g^-1), Ni (33 μg g^-1), Cu (25 μg g^-1), Zn (59 μg g^-1) and Pb (19 μg g^-1) in the sediment samples were found to be of medium mean concentrations. The other metals were present at trace levels (<1 μg), including As and Hg in the fish and sediment samples. There was an appreciable increase in␣metal concentrations in going from the water to the sediment samples. The probable source of the pollutants is anthropogenic, arising from agricultural activities, corrosion/abrasion of the ferrous steel material and additives in the lubricants and insulation used for auxiliary services on the turbine floor of the dam constructed on the lakes. However, natural geological sourcing from the underlying lake rock cannot be totally ignored, particularly the high levels of Fe and Mn in the sediment samples. The potential risk for human exposure to these metals emanates from the fish caught in the lakes and subsequently consumed, as there are already significant levels of these metals in the two fish species analysed, Tilapia (Oreochromis niloticus) and Chrysicthys (Chrysicthys auratus).     

Notes on the Nerita (Archaeogastropoda) populations of Aldabra Atoll,Indian Ocean

Nerita undata, N. plicata, N. polita, N. albicilla and N. textilis are common intertidal gastropods on Aldabra Atoll. Each species prefers a different level on the shore and/or different degrees of exposure to wave action. Patterns of zonation, population size-frequency structure and biomass are given. N. undata exhibits 2 distinct ecophenotypes. Normal types occur on expsed to moderately sheltered shores but are replaced by type B in extremely sheltered conditions. Differences in shell morphology and population structure are also noted. Foraging by all species was confined to hours of darkness, generally at low tide. Activity of N. polita was induced slightly on overcast days. N. undata and N. textilis are cryptically coloured and often visible during the day. N. plicata is conspicuous, but is protected by a strong shell. N. polita and N. albicilla are often brightly and variably coloured, but both are concealed during daylight. No Nerita were found infected with trematodes, suggesting that the degree of infection was extremely low. Habitats of the Aldabran Nerita are compared with 3 species on Barbados, West Indies.     

基于景观生态学的天目湖湿地公园规划

通过野外调查和利用1∶1000、1∶10000地形图作GIS判读分析,以景观生态学原理为指导,对天目湖湿地公园进行规划。在将天目湖湿地划分成平坦开阔区、岛山、浅冲和廊道4类斑块基础上,以保护和利用湿地资源,发挥廊道的生态功能,突出绿斑、蓝带、开敞空间的整合为规划控制思路,对规划出的水生花卉园、湖滨生态园、平桥河生态廊道、芦苇园、林岛园、"双龙"入湖生态景观带以及生态产业和生态人居园7类用地布局作了描述。     

Physiological ecology of four Polysiphonia species (Rhodophyta,Ceramiales)

Photosynthesis and respiration of 4 species of the marine red algal genus Polysiphonia were evaluated under a variety of light, temperature and salinity conditions. The manometric results were compared with the local distribution and abundance of each species. The species can be separated into two distinct categories based on their overall distribution and temperature optima: (1) cold water plants [P. lanosa (L.) Tandy and P. elongata (Hudson) Sprengel], with peak photosynthesis at 21° to 24°C, but with active photosynthesis as low as 5°C; (2) plants with warm-water affinities [P. nigrescens (Hudson) Greville and P. subtilissima Montagne], having photosynthetic optima at 27° to 30°C, and exhibiting little or no photosynthesis below 10°C. The plants from the first group exhibit thermal injury at temperatures of 25°C and show a narrow tolerance to low salinities during periods of high temperatures. The plants from the second group show thermal injury at 30°C and have a wider tolerance to low salinities. The horizontal distribution of the 4 Polysiphonia species within the Great Bay Estuary System of New Hampshire, USA, is primarily governed by their tolerances to high temperatures and low salinities. The temperature optimum for each of the species corresponds to its particular estuarine distribution. Thus, P. subtilissima, having the highest temperature optimum, penetrated furthest into the Estuary, while P. lanosa, having the lowest temperature optimum, was restricted to the more coastal stations. There was a good correspondence between the natural distribution patterns and the manometric results.Published with the approval of the Director of the New Hampshire Agricultural Experiment Station as Scientific Contribution No. 731.Scientific Contribution No. 4 of the Jackson Estuarine Laboratory.     

Chemical fractionation of metals in core sediments of Orogodo River,southern Nigeria

Sequential chemical extraction of metals (Cu, Ni, Mn, Fe, Pb, Cr, and Zn) from core sediments of the Orogodo River was carried out with a view of providing information on the phase distribution of these metals with respect to depths and seasons. The results indicate that copper was speciated into organic matter/sulfide, Fe–Mn oxides, and residual forms at 0–5?cm depth while at deeper sections copper was predominantly in the residual form. Nickel was speciated mainly into Fe–Mn oxides and residual forms. The average of lead in various particulate phases of the sediment are 0–100% for residual; 0–8% for carbonate; 0–16.2% for exchangeable; 0–10% for organic matter/sulfide form and 22–56% for Fe–Mn oxides bound metals. Manganese was speciated into exchangeable (10–36%) and Fe–Mn oxides bound (10–48%) at the surface layers of 0–20?cm depths and predominantly in the residual form in deeper sections implying partitioning into trioctahydral clay and/or well-defined crystalline oxides. Iron was predominantly in the Fe–Mn oxides and residual fractions, less than 8% in the organic fraction, and 24.4–37.3% in the exchangeable and carbonates fractions at the surface. The percentage contributions of iron in the exchangeable and carbonate fractions decreased to 3.2% at 55–60?cm depth. The amount of chromium in the exchangeable fraction ranged from 0% to 7% for exchangeable; 0–26.5% for organic matter/sulfide bound; 3.8–17.9% for Fe–Mn oxides; and 46.8–100% for residual fraction. The mobility factors of the metals indicated that these metals were relatively mobile at top sections as compared with deeper sections. The overall picture of metal mobility and availability indicates potential contamination risk by Fe, Zn, Mn, and Pb in the Orogodo River sediment system.     

A review of the chemical ecology of the Cerambycidae (Coleoptera)

Summary. This review summarizes the literature related to the chemical ecology of the Cerambycidae and provides a brief overview of cerambycid biology, ecology, economic significance, and management. Beetles in the family Cerambycidae have assumed increasing prominence as pests of forest and shade trees, shrubs, and raw wood products, and as vectors of tree diseases. Exotic species associated with solid wood packing materials have been notable tree killers in North American urban and peri-urban forests. In forested ecosystems native species respond to disturbances such as fires and windstorms, and initiate the biodeterioration of woody tissue. Eggs are laid by females, on or through the bark surface of stem and branch tissue of moribund, recently killed or decomposing woody plants; larval cerambycids (roundheaded woodborers) typically feed in the phloem and later in the xylem. Females will also, in some cases, select living hosts, e.g. adult conifer and angiosperm trees, for oviposition. Research on the chemical ecology of over 70 species has revealed many examples of attractive kairomones (such as floral volatiles, smoke volatiles, trunk and leaf volatiles, and bark beetle pheromones), repellents and deterrents, oviposition stimulants, short- and long-range sex pheromones, and defensive substances. Emerging generalities are that attractants tend to be monoterpenoids and phenolic esters; oviposition stimulants are monoterpenoids and flavanoids; short-range sex pheromones are female-produced, methyl-branched cuticular hydrocarbons; and long-range sex pheromones are male-produced -hydroxy ketones and (,)-diols ranging in length from 6 to 10 carbons. The latter compounds appear to originate from glands in the male thorax; putative defensive substances originate from metasternal secretory pores or mandibular glands. In one unusual case, a flightless, subterranean female that attacks sugar cane produces a sex pheromone that is derived from the amino acid isoleucine. With significantly more than 35,000 species of Cerambycidae worldwide, these generalities will be subject to change as more species are examined. Addendum The authors would like to point out that the electronic version is more accurate than the printed version.     

The foraging ecology of hoverflies (Diptera,Syrphidae): circular movements on composite flowers

Summary An energetic analysis of the foraging behaviour for nectar of Eristalis tenax L. is presented. The rate of energy gain while foraging on Aster is low (0.01 W) relative to similar calculations for bees, but the flies can fill their crop in about 75–220 min. Flies visit the nectar-bearing ring of florets on a capitulum systematically, leaving when they have circled it once (Fig. 1). A simple decision-making rule appears to be used to decide when to leave.     

Population ecology and secondary production of the polychaete Loimia medusa (Terebellidae)

In soft-sediment marine and estuarine habitats, population dynamics of resident species are an important aspect of commnity structure and function, yet the population dynamics of many members of these communities remain poorly studied. The population dynamics and secondary production of the infaunal terebellid polychaete Loimia medusa (Savigny) were investigated in a shallow sand habitat of the York River, Chesapeake Bay, Virginia, between June 1989 and December 1990. Monthly sampling throughout 1 yr revealed that individuals were present year-round with maximum densities of 60 ind m^-2 and a life span of 1 yr. Abundances were highest from August through September when two cohorts recruited to the population. Mean individual growth was highest in summer, and appeared to be a function of temperature rather than food limitation. Adults were reproductive from May through October and exhibited high fecundity; the number of oocytes segment^-1 ranged from 201 to 15840 among worms. Larvae initially appeared approximately 1 mo after gametes were first observed in adult L. medusa, and these larvae appeared to spend less than 1 mo in the plankton. Abundances of larvae in the water column were significantly higher around new moon, suggesting lunar spawning periodicity. New recruits attained sexual maturity within 2 mo of settlement. Secondary production was 3.3 g ash-free dry wt m^-2 yr^-1 and the P/B (production/biomass) ratio was 3.0. Despite equilibrium species characteristics such as large size, high fecundity, and planktonic larvae, L. medusa exhibits some characteristics typically ascribed to opportunistic species, namely, the capacity for rapid growth and maturation, a short life span and a relatively high P/B ratio. This mixture of life history characteristics emphasizes that there is no simple dichotomy between opportunistic and equilibrium species. We caution that the dominance of large infaunal polychaetes in soft-bottom estuarine and marine environments may not be a useful indicator of undisturbed habitats.     

Notes on the occurrence of Tilapia zillii (Pisces) in Suez Bay

Tilapia zillii Gervais is recorded for the first time from Suez Bay off the Institute of Oceanography and Fisheries, Ataqa (UAR), during October and November 1965 and 1966. Salinities and temperatures of surface sea water ranged from 42 to 42.79 and 23° to 24.4°C, respectively. The occurrence of specimens of T. zillii in the Bay indicates that it can tolerate high salinities and survive in the sea.     

Halistaura bruuni sp. nov. (Leptomedusae,Mitrocomidae) with notes on its distribution and ecology

A new hydromedusa collected in 1963 in the Bay of Bengal during the International Indian Ocean Expedition by the RV Anton Bruun is here described as Halistaura bruuni sp. nov. Some environmental data are given. The new species is characterized by a number of open marginal vesicles approximately equal to that of the tentacles, oval gonads on the distal half of the radial canals, and by the presence of nematocyst depots in the tentacle bulbs.Publ. No. 273 of the Instituto Oceanográfico da U. S. P.     

Interactions between light and temperature on the physiological ecology ofGracilaria tikvahiae (Gigartinales: Rhodophyta)

Main effects and interactions of light and temperature on rates of growth (), net photosynthesis (P_s), and dark respiration (R) of the red seaweedGracilaria tikvahiae were investigated in outdoor, nutrient-replete continuous-flow seawater culture chambers. Below 15°C,G. tikvahiae did not grow and between 15° and 30°C, both main effects and interactions of light and temperature on and P_s were significant, which explains the occurrence of this alga as a summer annual in its northern range. Temperature interacted with light (I) through its influence on the vs I and P_s vs I curves. The initial slope of the vs I curve, , the light saturation intensity, I_s, and maximum growth rate, _max, were all significantly lowerat 15°C compared to 20°, 25°, or 30°C. Maximum values of _max, the P_s:R ratio and the net photosynthesis:gross photosynthesis ratio (P_s:P_g) all occurred at 25°C, suggesting that this is the best temperature for growth ofG. tikvahiae. Values for P_max increased up to 30°C, indicating that the temperature for maximum growth and net photosynthesis are not the same forG. tikvahiae. Significant photoinhibition of growth and photosynthesis at full incident sunlight (I₀) occurred at 15°C but not at 20°, 25°, or 30°C. Steele's equation fit the 15°C vs I data best, whereas the hyperbolic tangent function fit the 20°, 25°, and 30°C data best. Main effects and interactionof light intensity and temperature on rates of R were also significant (P<0.001). R was highly intercorrelated with and P_s (0.86r0.94), indicating that R inG. tikvahiae is primarily regulated by growth rate and not temperatureper se. Environmental factors that regulate growth, such as light intensity, exert a great influence on R inG. tikvahiae.     

Interactions between light and temperature on the physiological ecology ofGracilaria tikvahiae (Gigartinales: Rhodophyta)

The biology and ecology of the Antarctic scallop Adamussium colbecki has been investigated on the west side of McMurdo Sound, Antarctica, principally at Explorers Cove, during the austral summer of 1981–1982. This conspicuous benthic invertebrate exhibits highest densities, 85 individuals m^-2, in shallow (4 to 6 m) water. Densities decrease to 20 m^-2 at 30 m. Biomass levels are highest in shallow water, 1 600 g wet wt m^-2. Provisional growth information suggests that 8 cm individuals are about 12 yr old. Mortality is apparently caused chiefly by a hyposaline lens of seawater, which forms under the sea ice during the summer melt; predators do not appear to be important. High biomass levels and a short generation time suggest that A. colbecki is an important species in a very productive community on the west side of McMurdo Sound. The shallow benthos of Explorers Cove is an important exception to the generalization that Antarctic ecosystems are dominated by indigestible filter-feeders.     

Seasonal variation and partition of trace metals (Fe, Zn, Cu, Mn, Cr, Cd and Pb) in surface sediments: relationship with physico-chemical variables of water from the Calabar River, South Eastern Nigeria

The seasonal variation and partition of trace metals (Fe, Cu, Zn, Mn, Cd, Cr and Pb) in the surface sediments of the Calabar River are reported. Chemical partition of the metals in the sediments reveals that 2–30% of the total metal load was contributed by the non-detrital (acid-soluble) fraction, while fine-grained host minerals/compounds are the main carriers of the detrital (acid-insoluble) fraction (70–98%). Using multivariate statistical analysis, the seasonal fluctuations in the distribution of some of the metals show significant influence by physio-chemical changes (dissolved oxygen, pH, salinity and conductivity) in the water column. Fe–Mn oxide grain coatings and sulphide materials have been identified as scavengers of some of the non-detrital and detrital trace metals in the sediments. On the basis of index of geoaccumulation (I-geo) and comparison with previous studies, the Calabar River surface sediments have been classified as unpolluted.     

Filter-feeding ethology of benthic invertebrates (ascidians). IV. Pumping rate,filtration rate,filtration efficiency

A combination of a direct and an indirect method has been used for the first time in the study of filter-feeding in benthic invertebrates. Experiments over 12 h periods under constant temperature, pH, light and feeding conditions have been carried out with 3 species of ascidians: Ciona intestinalis (Linné, 1767); Phallusia mammillata (Cuvier, 1815) and Styela plicata (Lesueur, 1823). In C. intestinalis and P. mammillata, no pumping rhythm has been found; the water flow was constant for 12 h, except for some brief accidental interruptions. In S. plicata, the particular rhythm of spontaneous periodical contractions recorded during the experiment were related to gamete emission. The speed of water flow, which was fairly constant during recording, varied considerably during the 12 h period; these variations were generally related to modifications in the diameter of the cloacal siphon. The average speeds, in cm sec^-1, lay between 5.7 and 9.5 for C. intestinalis, 5.2 and 19.4 for P. mammillata, and between 5.3 and 10.7 for S. plicata. Variations in the pumping-rate were small, oscillating around a mean value. In ml h^-1 g^-1 dry weight of organs these were 5,829 to 5,982 (mean=5,906) for C. intestinalis, 6,142 to 6,592 (mean=6,312) for P. mammillata, 1,0508 to 1,1505 (mean=1,0708) for S. plicata. Filtration was continuous without any particular rhythm; filtration rates in ml h^-1 g^-1 dry weight of organs varied between 4,244 and 4,418 (mean=4,331) for C. intestinalis, 4,620 and 4,960 (mean=4,779) for P. mammillata, 8,482 and 9,078 (mean=8,760) for S. plicata. The curves representing pumping and filtration were clearly parallel, indicating that filtration efficiency did not vary greatly during the course of an experiment; the rates obtained were 65 to 87% (mean=74%) for C. intestinalis, 66 to 88% (mean 76%) for P. mammillata, and 73 to 90% (mean=80%) for S. plicata. The slightly higher mean value in S. plicata is probably related to the higher complexity of the branchial apparatus of this species.     

Sensory ecology of a semi-aquatic spider (Dolomedes triton)

Summary Preferred ambush sites of fishing spiders Dolomedes triton (Pisauridae) were investigated, primarily with respect to aquatic vegetation and wave action, at five locations differing in these variables along the shore of Dow Lake (near Athens, Ohio). The linear density of spiders correlated positively with the presence of aquatic vegetation. D. triton most often stood at a distance from shore proportional to the width of the zone of floating and emergent vegetation (Fig. 2). Usually they positioned their bodies in the horizontal plane on floating living or dead plant parts. Spider density was negatively correlated with the amplitude of wind-generated waves (Fig. 4). The maximum energy of these waves measured on breezy days was at a frequency of 1.4 Hz, with no components exceeding 10 Hz (Fig. 5). Spiders could discriminate high-amplitude (up to 40 mm) wind waves from prey waves, probably since the latter have substantially higher frequencies (Figs. 3, 5).     

Seasonal variation assessment of impact of industrial effluents on physicochemical parameters of surface water of River Challawa,Kano, Nigeria

The physicochemical characteristics of the River Challawa in the Kumbotso Local Government Area of Kano State were studied across four seasons (warm and dry, cold and dry, hot and dry, and warm and wet seasons) between October 2006 and August 2008. Physicochemical parameters like pH, electrical conductivity (EC), total dissolved solids (TDSs), total suspended solids (TSS), alkalinity, turbidity, hardness, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia, chloride, nitrate, sulfate, and phosphate were analyzed and compared with standard permissible limits. The mean range of parameters determined across the seasons revealed: 8.36–8.59 for pH; 209.57–335.27 µS cm^?1 for EC; 134.05–208.5 mg L^?1 for TDS; 182.4–273.45 mg L^?1 for TSS; 125.3–276.07 mg L^?1 for hardness; 16.11–40 mg L^?1 of CaCO₃ for alkalinity; 2.76–3.78 mg L^?1 for DO; 1.9–43.33 mg L^?1 for BOD; 231.67–310.06 mg L^?1 for COD; 221.67–441.67 mg L^?1 for turbidity; 17.98–35.89 mg L^?1 for chloride; 5.12–8.89 mg L^?1 for nitrate; 37–558.83 mg L^?1 for sulfate; and 0.47–0.81 mg L^?1 for phosphate. Data showed that all parameters determined were significantly different among the various sampled sites across seasons. With the exception of COD, EC, and phosphate, all other parameters determined were within the WHO and USPH standard limits.     

Comparative feeding ecology of two sympatric rockfish congeners,Sebastes caurinus (copper rockfish) and S. maliger (quillback rockfish)

Possible differences in the diet or metabolism of sympatric finback and humpback whales in the Gulf of St. Lawrence were investigated through analysis of their blubber fatty acids. Free-ranging finback (Balaenoptera physalus, n=19) and humpback (Megaptera novaeangliae, n=10) whales were sampled through biopsy during summer 1991. The two species differed in the chemical composition and stable carbon isotope distribution of fatty acids extracted from their outermost blubber layer. Finback blubber was slightly but significantly richer in its relative proportions of 12:0, 13:0, i14:0, 17:0, 18:1 n9, 18:1 n7, and 20:0 (probability of difference 99%), 18:2 n6, 18:0, and 19:0 (probability 95%), and 16:1 n5 and 16:0 (90%). The stable isotope ratio of finback total fatty acids averaged-25.5±0.4%. Humpbacks contained relatively more i16:0, 18:1 n5, 20:5 n3, and 22:6 n3 (probability 99%), 16:1 n7, i18:0, 20:4 n6, and 22:5 n3 (95%), and 20:4 n3 (>90%). Their fatty acid ¹³ averaged -25.8±0.5% (different from finbacks with a probability of 95%). There was no significant difference between the two species in the relative proportions of 14:1, 14:0, i15:0, a15:0, 15:0, i17:0, a17:0, 17:1, 20:1 n9, 20:1 n7, 22:1 n11, or 22:1 n9, which together made up one-third of total fatty acids. We used principal component and cluster analyses to integrate and visualize the differences in the chemometric data sets. The chemical and isotopic differences found in the present study are consistent with a slightly lower trophic position for humpbacks compared to finbacks in the Gulf of St. Lawrence, reflecting a difference in long-term, average diet.     

Feeding behavior and ecology of shallow-water unstalked crinoids (echinodermata) in the Caribbean Sea

The feeding behavior, living position, and skeletal morphology of 8 species of reef-dwelling Caribbean comatulid crinoids are intimately related to the regime of water movement prevailing in the microhabitat. These adaptations are related to the dependence of the crinoid suspension-feeding mechanism on externally produced water movements for a continuous food supply. Greater numbers of co-occurring comatulid species (6 to 7) and larger populations have been found off Colombia and Panamá than off Curaçao and Jamaica (4 species). It is suggested that these differences may be related to increased or diversified primary productivity close to the larger land masses. Overal food availability as determined by primary productivity may, thus, be an important factor controlling the regional diversity and abundance of these species.     

Sexual dimorphism and the mating ecology of polar bears (Ursus maritimus) at Svalbard

We assessed the role of size, mass, and age in mating and non-mating polar bears (Ursus maritimus) at Svalbard, Norway, during the spring breeding season. The ratio of male to female mass, in male-female pairs, ranged from 1.00 to 3.02 ([`(x)] = 1.99 overline x = 1.99 ) indicating that mating males were larger than mating females but with substantial variation. Paired males were older than unpaired males and male mass was related to age. However, males paired with females were not significantly different in body mass from those males caught alone. Wounds and scars resulting from fights between males began at about 6 years of age and peaked at about 17 and 20 years of age, respectively. The frequency of broken canines in males, presumably due to increased male-male conflicts, increased with age but showed little increase in females. The wide range of male size in male-female pairs and the age-related signs of injury suggest that male polar bears engage in both scramble competition and contest competition for access to breeding females. The mating system of polar bears is variable but is best described as female defense polygyny or serial monogamy.