scholarly journals Inter-algal movement of marked blue-rayed limpets, Patella pellucida L., between kelps on the lower shore

2001 ◽  
Vol 67 (3) ◽  
pp. 398-400 ◽  
Author(s):  
D. McGrath
Keyword(s):  
Lower Shore

Calcareous meiofauna associated with the calcareous alga Corallina officinalis on bedrock and boulder-field shores of Ceredigion, Wales, UK

2020 ◽  
pp. 1-13
Author(s):  
Brent Wilson ◽  
Lee-Ann C. Hayek
Keyword(s):  
Breaking Waves ◽  
Red Alga ◽  
Low Energy ◽  
Rock Pools ◽  
Lower Shore ◽  
Calcareous Alga ◽  
Corallina Officinalis ◽  
Modes Of Life ◽  
Sessile Organisms

Abstract The intertidal coastline of Ceredigion, Wales, comprises a patchwork of unstable sand and cobble beaches, and stable bedrock areas and boulder-fields. The last two shoreline types support rock-pools with growths of the red alga Corallina officinalis, the thalli of which are a popular substrate for calcareous epiphytes. Replicate samples of C. officinalis (four per site) were taken from (a) three bedrock sites (Ceinewydd, Aberystwyth Victoria Rocks and Castle Rocks) and (b) three boulder-fields (Llanon, Aberaeron lower shore (Aberaeron LS), Llanina) on the lower shore. The middle shore boulder field at Aberaeron (Aberaeron MS) was also sampled. These replicates were examined for calcareous meiofauna (63–2000 μm) not previously examined as a community: spirorbids, foraminifera, gastropods, bryozoans, ostracods and ophiuroids. These were assigned to sessile and vagile modes of life. The sessile association overwhelmingly dominated bedrock coastlines and the Aberaeron MS, while the vagile association was at its most abundant on the Corallina from lower shore, stable boulder-fields. Gastropods were almost entirely limited to Corallina on boulder-fields. We hypothesize that the boulders induce low-energy turbulence among breaking waves, allowing the less firmly attached vagile meiofauna to dominate on C. officinalis in rock-pools in lower shore boulder-fields. The small attachment area of sessile organisms allows them to settle bedrock sites in greater densities than do vagile organisms at boulder-field sites, which are presumed to require larger foraging areas.

Rhythms of activity and foraging in the intertidal insect Anurida maritima: coping with the tide

2000 ◽  
Vol 80 (1) ◽  
pp. 189-190 ◽  
Author(s):  
Fiona K. McMeechan ◽  
Andrea Manica ◽  
William A. Foster
Keyword(s):  
Food Supply ◽  
Feeding Activity ◽  
Soil Surface ◽  
Constant Light ◽  
Locomotory Activity ◽  
Main Function ◽  
Lower Shore ◽  
Free Running

The intertidal insect Anurida maritima (Apterygota: Collembola) has a circatidal rhythm of locomotory activity on the soil surface which was observed during both the day and the night. The main function of this activity was foraging for food. When a superabundant food supply was provided on the upper shore, this completely repressed the usual migration to the lower shore. There was a clear rhythm in feeding activity which was highest shortly after the sea uncovered the insects' shelters and declined rapidly during the intertidal period. The circatidal rhythm of locomotory activity persisted in the laboratory in constant light for seven days (15 cycles). A free-running rhythm underlying the degree of aggregation was also detected.

Distribution, abundance and recruitment of Chthamalus (Crustacea: Cirripedia) populations along the central coast of Portugal

2001 ◽  
Vol 81 (3) ◽  
pp. 461-468 ◽  
Author(s):  
P. Range ◽  
J. Paula
Keyword(s):  
Reproductive Season ◽  
Tagus Estuary ◽  
Rocky Shores ◽  
Central Coast ◽  
Lower Shore ◽  
Exposed Shore ◽  
Chthamalus Montagui ◽  
Main Factors ◽  
One Year ◽  
Cross Fertilization

The distribution, abundance and recruitment of Chthamalus species were studied for one year at two rocky shores on the central coast of Portugal. Chthamalus montagui is the most abundant intertidal barnacle on the Portuguese mainland. Higher abundance of C. montagui was found on the lower levels of the more sheltered shore, which is closer to the influence of the Tagus estuary. Chthamalus stellatus was also present, in very low densities, and always confined to the lower level of the barnacle zone. Chthamalus stellatus was more common at the shore farther away from the estuary, in which exposure to wave action is higher. The metamorphs of C. stellatus settled at the studied shores are considered to be immigrants from other populations, where the density of adults is sufficient for cross-fertilization to occur. Chthamalus spp. recruited almost continuously throughout the year, with a peak between July and September and a gap during February and March. Variations in phytoplanktonic assemblages and temperature may be the main factors controlling the reproductive season of Chthamalus spp. Recruitment was usually stronger on the lower shore levels but extended for a longer period higher on the shore. Seasonalvariations of C. montagui abundance were greater on the lower levels of the more exposed shore. This is probably due to faster growth and higher mortality of barnacle populations occupying the lower shore levels at the more exposed habitats.

scholarly journals Marine Turf of an Invasive Alga Ousts Lugworms From Lower Shore

2021 ◽  
Author(s):  
Karsten Reise ◽  
Dagmar Lackschewitz
Keyword(s):  
North Sea ◽  
Wadden Sea ◽  
Benthic Fauna ◽  
Algal Turf ◽  
The Novel ◽  
Mosaic Pattern ◽  
Arenicola Marina ◽  
Lower Shore ◽  
Tide Level ◽  
Invasive Alga

Abstract Bare sandy flats at and below low tide level were observed in 2020 to have been invaded by an introduced grass-like alga, Vaucheria cf. velutina (Xanthophyceae). A dense algal turf accumulated and stabilized mud where resident seniors of the lugworm Arenicola marina had reworked rippled sand. Algae and worms were incompatible. Initially, rising patches with algal turf alternated with bare pits where lugworms crowded. Their bioturbation inhibited young algae, while the felt of established algal rhizoids clogged feeding funnels of worm burrows. Eventually, the mosaic pattern of competitors gave way to a coherent algal turf without lugworms. Concomitantly, a rich small-sized benthic fauna took advantage of the novel algal turf. This exotic Vaucheria has the potential for taking over at the lower shore of the Wadden Sea (eastern North Sea, European Atlantic).

scholarly journals Impact of Climate Change on Coastal Meadows: a Mesocosm Approach

2021 ◽  
Author(s):  
Thaisa Bergamo ◽  
Raymond Ward ◽  
Christopher Joyce ◽  
Kalev Sepp
Keyword(s):  
Climate Change ◽  
Ecosystem Services ◽  
Water Level ◽  
Plant Communities ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Migratory Bird ◽  
Lower Shore ◽  
Wide Range ◽  
Coastal Meadows

<p>Coastal meadows supply a wide range of ecosystem services, including high carbon storage, high plant species richness and a wide variety of habitat types, which supports breeding and migratory bird populations. However, global change (climate change, pollution and environmental degradation) poses several threats to the stability and ecosystem services supplied by coastal meadows. Specifically within the Baltic Sea, recent estimates foresee various degrees of sea level rise along the Estonian coast and salinity is expected to decrease in the eastern Baltic and increase in the west. In order to assess the effects of climate change in coastal wetlands, an investigation of the influence of changes in water level and salinity on coastal wetland plant communities was undertaken. Future scenarios of Estonian coastal wetlands were evaluated using a three-year mesocosm experiment simulating altered environmental conditions. The response of three plant communities (Open Pioneer, Lower Shore and Upper Shore) were assessed in terms of changes in species composition through time. The experiment included 45 mesocosms, 15 per community with 5 treatments (3 replicates per treatment) with control, altered water level and salinity. Exploratory analysis, ANOVA and NMDS, were used to assess changes in the plant communities throughout the duration of the project. Preliminary results show that Open Pioneer is more sensitive to decreased salinity. A decrease in percentage cover of species adapted to high salinity concentration (e.g. <em>Spergularia marina</em>) was observed. On the other hand, Lower Shore didn’t show any clear changes with the treatments. In order to obtain deeper insights, further analysis are needed to reveal complex community shifts under altered physical conditions.</p>

scholarly journals Spatial-temporal distribution and recruitment of Stramonita haemastoma (Linnaeus, 1758) (Mollusca) on a sandstone bank in Ilhéus, Bahia, Brazil

2011 ◽  
Vol 71 (4) ◽  
pp. 799-805
Author(s):  
JJB. Santos ◽  
G. Boehs
Keyword(s):  
Temperature Variation ◽  
Population Ecology ◽  
Temporal Distribution ◽  
Egg Capsules ◽  
Lower Shore ◽  
Stramonita Haemastoma ◽  
Continuous Reproduction

We examined aspects of the population ecology of the gastropod Stramonita haemastoma at Ilhéus, Bahia, Brazil. We collected monthly from October 2007 through September 2008 on a sandstone bank 1.5 km long, on which two points and two sampling levels were defined. We took five previously randomised replicates at each level, using a square enclosing an area of 0.0625 m². The snails were photographed, counted, and measured at the site. Both recruits and other individuals in the population preferentially inhabit the regions closer to the lower shore, where they are submerged for longer periods and are less subject to physiological stresses caused by temperature variation and desiccation. The cracks and holes in the bank serve as refuges and places for S. haemastoma to lay their egg capsules. Recruits were observed throughout the study period, and the population showed continuous reproduction.

The relationship between the distribution of genetically distinct inbred lines and upper lethal temperature in Lasaea rubra

1990 ◽  
Vol 70 (3) ◽  
pp. 557-570 ◽  
Author(s):  
H. Walters-Tyler ◽  
J. Davenport
Keyword(s):  
Inbred Line ◽  
Genetic Basis ◽  
Thermal Response ◽  
Indirect Evidence ◽  
High Water ◽  
Inbred Lines ◽  
Rocky Shores ◽  
Lower Shore ◽  
Single Temperature ◽  
The Relationship

Lasaea rubra is an inbreeding bivalve species, living at most heights on rocky shores. Freshly collected animals from different shore heights showed significantly different upper median lethal temperatures (MLTs), with upper shore animals having higher MLTs than lower shore specimens. Experiments with animals acclimated for at least one month to a single temperature (15°C) demonstrated that these differences in upper MLT were unaffected by thermal acclimation. Electrophoretic investigation showed that the differences in thermal response had a genetic basis. Homogeneous populations of the high-water inbred line (‘Inbred line A’) had a higher MLT than homogeneous populations of ‘Inbred line C’ which was found on the middle and lower shore. No differences were detected between the MLTs of separate populations of Inbred lines A or C. A third inbred line (‘Inbred line B’) was found on the middle shore, but no homogeneous populations were found. However, indirect evidence suggests that Inbred line B has a thermal response intermediate between those of Inbred lines A and C. Study of populations made up of mixtures of inbred lines confirmed the relationship between upper MLTs and genetic composition of the population.

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