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1.
Time-lapse videography of limpets mounted with light-emitting diodes was used to monitor the movements of a population of the non-homing Cellana grata on a vertical gully wall in Hong Kong. Animals were monitored for >7 days to examine spatial and temporal variation in their behaviour as the tides transited from a semi-diurnal to an almost diurnal pattern. Movement was synchronised with the tides, irrespective of the day–night cycles. Limpets rested low on the shore and were stimulated to move by the rising tide. Individuals moved up shore with the flooding tide, maintaining themselves in the awash zone, and then down shore on the ebbing tide, until they reached a resting height when the tide then fell beneath them, exhibiting ‘zonal shuttling’. A tight coupling of limpet position to tide height persisted through the changing tidal pattern, and almost all animals displayed the same organisation of activity over all tides. Initiation of activity and maximum height reached were probably controlled by the tides, but the cessation of activity may have been controlled by an internal clock. The pattern observed is consistent with the threat of attack from aquatic predators coupled with the need to minimise physical stresses while exposed. It is also consistent with the avoidance of grazing lower on the shore where interspecific competition may be more intense. Limpets showed two peaks of activity per tide, corresponding to when the rate of change of tide height was the greatest, except when tides became much reduced during the transit to a diurnal pattern. Movement was triphasic: an initial rapid phase, followed by a slower phase in the high shore and then a rapid phase before the limpets stopped moving. This structure is common in limpets and in this case is likely to be a consequence of animals maintaining themselves within the awash zone. Tide height appears to determine foraging activity, but with modifications in the behaviour in response to factors operating at more local temporal and spatial scales. 相似文献
2.
The temperate sea anemone Anthopleura elegantissima is facultatively symbiotic with unicellular algae. Symbiotic A. elegantissima can supplement heterotrophic feeding with excess photosynthate from their algal partners, while asymbiotic individuals must
rely solely on heterotrophy. A. elegantissima individuals were collected from Swirl Rocks, Washington (48°25′6″ N, 122°50′58″ W) in July 2010, and prey capture and feeding
characteristics were measured to determine whether asymbiotic individuals are more efficient predators. Feeding abilities
were then measured again after a 3-week exposure to full sunlight or shaded conditions. Freshly collected asymbiotic anemones
had larger nematocysts, but symbiotic individuals showed greater nematocyte sensitivity. Sunlight enhanced digestion and reduced
cnida density in all anemones regardless of symbiotic state. Results suggest that the phototropic potential of A. elegantissima, as influenced by symbiotic condition, has little effect on heterotrophic capacity. The anemones appear to maximize heterotrophic
energy input independent of the presence or identity of their algal symbionts. 相似文献
3.
A bottom-mounted upward-facing 38-kHz echo sounder was deployed at ~400 m and cabled to shore in Masfjorden (~60°52′N, ~5°24′E), Norway. The scattering layers seen during autumn (September–October) 2008 were identified by trawling. Glacier lanternfish
(Benthosema glaciale) were mainly distributed below ~200 m and displayed three different diel behavioral strategies: normal diel vertical migration
(NDVM), inverse DVM (IDVM) and no DVM (NoDVM). The IDVM group was the focus of this study. It consisted of 2-year and older
individuals migrating to ~200–270 m during the daytime, while descending back to deeper than ~270 m during the night. Stomach
content analysis revealed increased feeding during the daytime on overwintering Calanus sp. We conclude that visually searching glacier lanternfish performing IDVM benefit from the faint daytime light in mid-waters
when preying on overwintering Calanus sp. 相似文献
4.
This study investigates the reproductive periodicity and reproductive output of the seagrass Zostera novazelandica on two intertidal reefs. Peak numbers of flowering shoots occurred during March (late summer) of two years at both sites
and no flowering shoots occurred during the winter months of July to September. There were greater numbers of flowering shoots
in seagrass patches in the low intertidal zone (up to an average of 55 per 0.1 m2) compared to the middle (up to 20 per 0.1 m2) and upper (up to 9 per 0.1 m2) zones, and about three times greater reproductive output in patches associated with tidepools compared to those not bordering
tidepools. The average number of inflorescences per shoot was 3.1 (±0.25) at one site vs 1.2 (±0.08) at the other, and showed
a progressive decrease from the lower shore to the upper shore. Patches associated with tidepools had twice the number of
inflorescences per shoot (2.8 ± 0.24) than patches not bordering tidepools (1.5 ± 0.16). The number of flowering shoots was
highly correlated with leaf width, leaf length, and ramet density, while the leaf-area index decreased from the lower shore
to the upper shore. The reproductive effort of plants, as measured by the percent biomass invested in flowering shoots during
peak reproduction, was significantly different between sites, tidepool associations, and shore level. For all the variables
measured, there was considerable spatial variation, with significant interaction terms between most factors investigated.
In laboratory experiments, more inflorescences were produced at light intensities of 30 and 300 μE m−2 s−1 than at 100 μE m−2 s−1. At a salinity of 17‰, 1.5 × the number of flowers was produced than at 33‰, while none was formed at 70‰. Plants cultured
at 5 °C had about three times the number of inflorescences than those at 15 °C, while none was formed at 25 °C.
Received: 25 June 1997 / Accepted: 24 September 1997 相似文献
5.
Assignment of individuals to populations based upon genetic data is an important ecological problem that requires many polymorphic
markers, often more than are available using single locus techniques. To demonstrate the utility of amplified fragment length
polymorphisms (AFLP) in studying larval dispersal and recruitment in coral populations, two sets of AFLP primers were used
to genotype colonies of the coral Agaricia agaricites Linnaeus from three widely separated geographic locations: the Bahamas (23°28′N, 75°42′W) and Key Largo, Florida (24°55′N,
80°31′W—two sites separated by 12 km) in 1995, and the Flower Garden Banks (FGB) in the Gulf of Mexico (27°55′N,93°36′W) in
1997. In addition to adult samples from each site, recruits were collected from settling plates placed on the East FGB for
1 year (1997–1998). The AFLP technique yielded 45 polymorphic markers. An analysis of molecular variance (AMOVA) showed significant
genetic differences among the four adult populations, even between the two Key Largo sites. The recruits were significantly
different from all adult populations except those from the FGB. Discriminant function analysis and the program AFLPOP were
used to assign individuals to populations. Using the adult AFLP-banding patterns to build the statistical models, both procedures
correctly assigned the majority of adults to their respective populations in simulations and assigned all but one of the recruits
to the Flower Garden population from where they were collected . The AFLP technique provides a simple and adaptable population
assignment method for studying recruitment processes in A. agaricites and other coral species.
Electronic Supplementary Material Supplementary material is available for this article at 相似文献
6.
Aerial sighting surveys were conducted in 2000 to evaluate the distribution and abundance of finless porpoise Neophocaena phocaenoides in the Inland Sea of Japan. We flew 60 north–south transects (2,218 km in total) at intervals of 6.43 km over the study area
between 131°3′ and 134°59′ E. In total, 148 groups were detected by two observers. The average group size was 1.56 individuals.
The effective strip half-width of each observer was estimated to be 107 m (coefficient of variation [CV] = 8.26%). Porpoise
abundance was estimated at 7,572 individuals and the density was as low as 0.506 individuals/km2 (CV = 17.3%). The sea is among the Japanese waters with the lowest density in spite of its favorable topographical conditions.
In the western stratum of the study area, where the estimated density was 1.31 individuals/km2, we observed a relatively regular distribution. In the central-eastern stratum, which had an estimated density of 0.208 individuals/km2, we confirmed a clumped distribution that was restricted to inshore waters or near islands. No individuals were observed
in waters between 132°51′ and 133°11′E, and between 133°43′ and 133°59′E, where sand dredging and other human activities have
been active, suggesting that habitat fragmentation has occurred. 相似文献
7.
Foraging behaviour in the South American sunstar Heliaster helianthus (Lamarck) was investigated quantitatively on a subtropical rocky shore in central Peru. H. helianthus feeds mainly on two mussel species, Semimytilus algosus (Gould) and Perumytilus purpuratus (Lamarck). A sequence of foraging behaviour was described and observations were made of the timing of attacks on mussel beds by sun-stars. Although H. helianthus is capable of foraging out of water, an unusual trait for asteroids, the timing of such foraging appears to be well adjusted to avoid the risk of prolonged heat and desiccation. Foraging activity began 4 h 52 min before high tide and 3 h 19 min after high tide, with a mode between 2 h 30 min and 2 h before high tide. Fifty-two percent of all foraging activity began between 3 h 30 min and 2 h before high tide, while only 12.4% began after high tide. This suggests that H. helianthus mainly relies upon changes in the rate of tidal increase as a cue to begin foraging. Foraging activity ceased between 3 h 40 min before and 4 h 29 min after high tide, with 48% ending between 2 and 0.5 h before high tide. The duration of foraging ranged from 19 to 190 min, with values between 30 and 80 min accounting for 67.4% of all observations. The median duration was 62 min. No significant correlation was detected between the time when foraging activity commenced and its duration. The intensity of foraging activity varied on consecutive days, with a general pattern of decreasing intensity after a day of relatively high activity. Foraging location in relation to a mussel bed was analysed on a marked, 8 m stretch of rocky shore. The numbers of foraging H. helianthus observed on different sections of the shore were related neither to the width of the mussel zone nor to the vertical position of the lower edge of the mussel zone, indicating that sun-stars do not rely upon these factors to assess prey availability and that ideal free distribution with regard to prey abundance does not occur on the spatial scale examined. 相似文献
8.
Spatial distribution and temporal variation of epibenthic assemblages of coralligenous biogenic rocky outcrops occurring in
the northern Adriatic Sea (45°04′–45°24′N; 12°23′–12°43′E) were investigated by photographic sampling from 2003 to 2006 at
12 randomly selected sites. The dominant reef-forming organisms were the encrusting calcareous algae (Lithophyllum stictaeforme, Lithothamnion minervae and Peyssonnelia polymorpha), while the main bioeroders were boring sponges (Cliona viridis, C. celata, C. thoosina, C. rhodensis, Piona vastifica) and the bivalve Gastrochaena dubia. Composition of the assemblages varied thorough years and among sites. Spatial heterogeneity, at local and regional scale,
prevailed over temporal variation. This variability was related both to the geo-morphological features of the outcrops and
to environmental variables. Sites clearly differed in the percent cover of reef builder and bioeroder species while only limited
temporal variation within site was found. Some taxa revealed complex intra-site temporal trends. These results provide valuable
information on the diversity and variability of epibenthic assemblages of the northern Adriatic coralligenous reefs, essential
for the management and conservation of these unique biogenic habitats. 相似文献
9.
The hypothesis that the behaviour of deep-sea scavenging fishes is influenced by seasonal input of organic matter from the
ocean surface was investigated by observing responses to baits placed on the sea floor at 4800 m depth in the NE Atlantic
(48°50′N; 16°30′W) during spring (April 1994). Data from the present study are compared with those from previous studies of
the same location made in summer 1989. The first fishes to arrive at baits were the grenadier Coryphaenoides (Nematonurus) armatus and the eel Histiobranchus bathybius, after delays of 28 and 29 min, respectively; these results are not significantly different from those of summer 1989. Similarly,
other indices of activity (staying time and swimming speed) showed no evidence of differences between years/seasons. However,
the rate of radial dispersal of bait (0.009 m s−1) by C. (N.) armatus was much slower than in all previous studies. A change in the size distribution of C. (N.) armatus to smaller individuals in spring 1994 was also evident. It is suggested that the fish on the abyssal plain may not comprise
a steady-state population and that major episodic or seasonal migrations may occur.
Received: 18 October 1996 / Accepted: 20 December 1996 相似文献
10.
Joseph M. O’Malley 《Marine Biology》2011,158(8):1887-1901
Scaly slipper lobster (Scyllarides squammosus) population ecology was examined using tag/recapture information at Necker Island (23°30′N; 164°35′W), Gardner Pinnacles
(25°00′N; 168°50′W), Maro Reef (25°30′N; 170°45′W), and Laysan Island (25°48′N; 171°45′W) in the Northwestern Hawaiian Islands
(NWHI) USA from 2002 to 2008. Although many aspects of S. squammosus life history and population dynamics were similar to those of other scyllarids, somatic growth differed from its congers.
Scyllarides squammosus growth abruptly declined at maturity and, because of this, growth at length was better described using the Schnute as opposed
to the more commonly von Bertalanffy growth model. Growth varied among locations, and survival varied among years; thereby
being the first documentation of variability in the life history of a scyllarid. This study has expanded knowledge of scyllarid
biology and documented that spatiotemporal variability in biological characteristics must be considered to understand and
describe the population ecology of this species and probably of other scyllarids. 相似文献
11.
The growth rates of the morphologically similar scyllarid lobsters Ibacus peronii (Leach, 1815) and I. chacei (Brown and Holthuis, 1998) are described using data from a tag/recapture study and from tagged lobsters kept in captivity.
Within particular size classes, we found no differences in moult increments between male and female I. peronii nor between male and female I. chacei. Small individuals of both species always had larger moult increments than larger individuals. For I. peronii, females moulted more frequently than males, and smaller size classes moulted more frequently than larger size classes. Female
I. peronii therefore grew more quickly than males and reached their estimated size at sexual maturity (51 mm carapace length) after
∼2 yr. Moulting of I. peronii was seasonal, with most lobsters (96.3%) moulting between October and January. We found no differences in growth rates of
I. peronii at two locations along the east coast of Australia: Coffs Harbour in New South Wales (30°18′S; 153°08′E), and Lakes Entrance
in Victoria (37°53′S; 148°00′E). For I. chacei, we found no differences in the frequency of moulting between males and females and, because we also found no differences
in the moult increments between males and females, the growth rates of both sexes were the same.
Received: 14 August 1999 / Accepted: 20 January 2000 相似文献
12.
Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel
(32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which
they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of
juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south
in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained
south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored
during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged
extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely
to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with
juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground. 相似文献
13.
Four populations of the native annual grassTriplasis purpurea were surveyed on coastal beaches along the south shore of Staten Island, NY, to determine the potential of this species to
colonize shoreline habitats mostly devoid of other vegetation. If the species can establish and maintain dense populations,
it may have conservation value for urban beaches disturbed by human activities. For two populations, survivorship, growth,
and reproduction were monitored at different distances from shore to determine the ability of this species to maintain viable
populations. At three sites,T. purpurea occurred in >75% of all quadrats and the highest density was 1195 plants/m2 at 74 m from shore in one recently disturbed site. Density generally increased with increasing distances from shore at low
tide (from ca. 40 – 90 m). Plants showed the greatest growth and reproduction at close distances to shore (30 – 40 m); part
of this effect was due to density in one population, but when density effects were removed statistically, there still remained
a decline in growth and reproduction with increasing distance from shore. Improved vigor nearest to shore may be due to continual
sand deposition. Survivorship showed a Type I pattern, with low mortality throughout the growing season. By colonizing newly-deposited
and continually shifting sands,T. purpurea can contribute to the earliest stages of ecological succession along disturbed beaches in eastern North America and may be
valuable to the development and management of urban coastal plant communities. 相似文献
14.
Four populations of the native annual grassTriplasis purpurea were surveyed on coastal beaches along the south shore of Staten Island, NY, to determine the potential of this species to
colonize shoreline habitats mostly devoid of other vegetation. If the species can establish and maintain dense populations,
it may have conservation value for urban beaches disturbed by human activities. For two populations, survivorship, growth,
and reproduction were monitored at different distances from shore to determine the ability of this species to maintain viable
populations. At three sites,T. purpurea occurred in >75% of all quadrats and the highest density was 1195 plants/m2 at 74 m from shore in one recently disturbed site. Density generally increased with increasing distances from shore at low
tide (from ca. 40–90 m). Plants showed the greatest growth and reproduction at close distances to shore (30–40 m); part of
this effect was due to density in one population, but when density effects were removed statistically, there still remained
a decline in growth and reproduction with increasing distance from shore. Improved vigor nearest to shore may be due to continual
sand deposition. Survivorship showed a Type I pattern, with low mortality throughout the growing season. By colonizing newly-deposited
and continually shifting sands,T. purpurea can contribute to the earliest stages of ecological succession along disturbed beaches in eastern North America and may be
valuable to the development and management of urban coastal plant communities. 相似文献
15.
The recovery of Ascophyllum nodosum, and the associated benthic community, was followed after repeated trampling disturbance at different intensities, from 2005
to 2010, at its southern limit (41°41′27″N; 8°50′57″W). The cover of A. nodosum and associated organisms and the demography of A. nodosum individuals in the most disturbed areas were followed over a recovery period of 54 months. Recovery of A. nodosum assemblages was negatively affected by increasing trampling intensity. After 54 months, the highest intensity plots were
still significantly different from control plots. Growth and mortality rates of A. nodosum increased shortly after disturbance but progressively recovered to levels close to control plots. The results of this study
demonstrate the sensitivity of this habitat-building species to human trampling and also show its plasticity to cope with
disturbance events. 相似文献
16.
The hydrothermal vent vestimentiferans Riftia pachyptila Jones, 1981 and Ridgeia piscesae Jones, 1985 live in habitats with different abundances of external CO2. R. pachyptila is found in areas with a high input of hydrothermal fluid, and therefore with a high [CO2]. R. piscesae is found in a range of habitats with low to high levels of hydrothermal fluid input, with a correspondingly broad range of
CO2 concentrations. We examined the strategies for dissolved inorganic carbon (DIC) use by the symbionts from these two species.
R. pachyptila were collected from the East Pacific Rise (9°50′N; 104°20′W) in March 1996, and R. piscesae were collected from the Juan de Fuca Ridge (47°57′N; 129°07′W) during September of 1996 and 1997. The differences in the
hosts' habitats were reflected by the internal pools of DIC in these organisms. The concentrations of DIC in coelomic fluid
from R. piscesae were 3.1 to 10.5 mM, lower than those previously reported for R. pachyptila, which often exceed 30 mM. When symbionts from both hosts were incubated at in situ pressures, their carbon fixation rates increased with the extracellular
concentration of CO2, and not HCO3
−, and symbionts from R. piscesae had a higher affinity for CO2 than those from R. pachyptila (K
1/2 of 7.6 μM versus 49 μM). Transmission electron micrographs showed that symbionts from R. piscesae lack carboxysomes, irrespective of the coelomic fluid [DIC] of their host. This suggests that the higher affinity for CO2 of R. piscesae symbionts may be their sole means of compensating for lower DIC concentrations. The δ13C values of tissues from R. piscesae with higher [DIC] in the coelomic fluid were more positive, opposite to the trend previously described for other autotrophs.
Factors which may contribute to this trend are discussed.
Received: 24 September 1998 / Accepted: 12 May 1999 相似文献
17.
Carolina Briones Ricardo Gui?ez Orlando Garrido Pablo A. Oyarzún Jorge E. Toro Montse Pérez 《Marine Biology》2012,159(8):1865-1870
For the first time in a marine bivalve species, geographic intraspecific variation in sperm morphology in the Chilean mussel, Perumytilus purpuratus, is reported. Samples were obtained in December 2010 from the rocky intertidal at three locations: Antofagasta (23o44′01.08′′S, 70o26′26.11′′W), Valparaíso (32o57′23.07′′S, 71o33′01.86′′W), and Valdivia (39°50′44.26′′S, 73°25′51.99′′W). Scanning electron microscopy was used to describe sperm traits, and genetic data were obtained by sequencing a 16S mtDNA 427-bp fragment. The results showed geographic intraspecific variation with two statistically significant patterns of genetically differentiated sperm morphologies. One genetic clade was found for Antofagasta and Valparaíso, displaying a unique sperm morphotype with a short acrosome accounting for 26 % of the head length, and the other from Valdivia, with a larger acrosome occupying 47 % of the head length. These results will lead to new research to distinguish among alternative hypotheses: the presence of cryptic species, incipient speciation, or a polymorphism in sperm traits of P. purpuratus. 相似文献
18.
19.
Olive ridley sea turtles display two different types of nesting behavior: in arribada (synchronous mass nesting) or solitarily. Contrarily to arribadas, little has been published about solitary nesters. This study aimed to expand the knowledge on internesting interval and
site fidelity of solitary nesting olive ridleys and to test a possible development of arribada nesting behavior. Data were collected in Sergipe (Brazil) over 125 km of beach from 10°30′S/36o23′W to 11°26′S/37o19′W, between
nesting seasons 2004/2005 and 2006/2007. From 962 tagged females, 173 were seen renesting. The average internesting interval
found was longer (22.35 ± 7.01 days) than previously described, which might relate to lower water temperatures during the
internesting period. Olive ridleys at Sergipe showed high nesting site fidelity, with consecutive nesting events occurring
in close proximity, non-randomly and dependently of previous events. Most of the consecutive nests were separated by 4.06–5.59 km.
Development of arribada nesting behavior was not confirmed. 相似文献
20.
The breeding performance of higher predators has often been used to monitor fluctuations in the abundance of important prey
stocks in marine ecosystems. The development of electronic data-loggers in recent years has also provided the opportunity
of using wide-ranging marine animals to measure physical oceanographic conditions. In this study, time–depth recorders (TDRs)
programmed to record temperature were deployed on female Antarctic fur seals (Arctocephalus gazella) at Bird Island, South Georgia (54°00′S; 38°02′W) during the breeding seasons 1994 to 1998. Temperature sensors had relatively
slow response times, and thermal radiation errors occurred during the day when seals spent a large proportion of their time
at the surface. Nevertheless, measurements provided temperature–depth profiles which were typical of the vertical stratification
of the ocean. During the early stages of a foraging trip temperature increased, suggesting that fur seals travelled northwards
from South Georgia towards the warmer waters of the Polar Front. In addition, higher temperatures were recorded by females
that remained at sea for longer, implying that these individuals also travelled further. Mean sea-surface temperature (SST)
increased from ∼1 to 4 °C from December to March and agreed with SSTs from ship, buoy and satellite. Future studies on marine
mammals which combine satellite tracking with oceanographic measurements are likely to provide valuable information on biophysical
aspects of the ocean.
Received: 16 June 1998 / Accepted: 13 February 1999 相似文献