scholarly journals Seasonal zonation patterns of the sandy beach bivalveDonax deltoides(Bivalvia: Donacidae) in subtropical eastern Australia

2019 ◽  
Author(s):  
Stephen Totterman
Keyword(s):  
Thermal Stress ◽  
Intertidal Zone ◽  
Sandy Beach ◽  
Seasonal Pattern ◽  
High Tide ◽  
Swash Zone ◽  
Eastern Australia ◽  
Zonation Patterns

ABSTRACTSeasonal low tide zonation patterns of the sandy beach bivalveDonax deltoidesare described from eleven beaches in subtropical eastern Australia. Ten low tide transects were sampled at equal along shore intervals along the length of each beach. Three quadrats were sampled at each of seven across shore levels on each transect, from the high tide drift line, across the intertidal zone and to the bottom of the low tide swash zone. Zone counts showed thatD. deltoidesshifted towards the low tide swash zone in summer and buried in the intertidal zone in winter. It is proposed thatD. deltoidesmoves down shore in summer to avoid thermal stress in the intertidal zone. This seasonal pattern is important when planning surveys for this species.

scholarly journals A “feet digging” swash zone sampling method for the sandy beach bivalve Donax deltoides (Bivalvia: Donacidae)

2019 ◽  
Author(s):  
Stephen Totterman
Keyword(s):  
Sampling Method ◽  
Sandy Beach ◽  
Low Cost ◽  
Sampling Unit ◽  
Recreational Fishing ◽  
Swash Zone ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Eastern Australia ◽  
Zone Sampling

ABSTRACTA “feet digging” method for sampling the sandy beach bivalve Donax deltoides was evaluated by comparison to quadrat-based results from eleven beaches in subtropical eastern Australia. The method was developed from a recreational fishing technique that involves twisting one’s feet into the thixotropic sand to dislodge buried clams which are then recovered by hand. Several plots are sampled across the swash zone in one five-minute sampling unit and the process is replicated at several locations along the beach. Mean feet digging clam counts were proportional to mean transect linear clam densities (r = 0.98). Clam length-frequency distributions from feet digging were similar to those from quadrat sampling except that feet digging was not effective for clams < 16 mm. Feet digging counts are sensitive to both across shore (tidal) and alongshore variation in clam abundance and were less precise than those from quadrat-based methods (CV 1.2× larger). However, feet digging is fast and the method should be useful for low cost surveys of Donax deltoides and similar “surf clams”.

scholarly journals Intertidal habitat use of bottlenose dolphins (Tursiops truncatus) in Bahía San Antonio, Argentina

2017 ◽  
Vol 98 (5) ◽  
pp. 1109-1118
Author(s):  
Els Vermeulen
Keyword(s):  
Habitat Use ◽  
Intertidal Zone ◽  
Tursiops Truncatus ◽  
San Antonio ◽  
Bottlenose Dolphins ◽  
High Tide ◽  
Marine Conservation ◽  
Shallow Waters ◽  
Encounter Rate ◽  
Western Atlantic

Very little information is available on bottlenose dolphin (Tursiops truncatus) habitat use in the South-western Atlantic. It is, however, essential in understanding their ecology and to improve conservation management. In this study, habitat use of bottlenose dolphins was examined in Bahía San Antonio, an area frequented by the species. Given the large tidal amplitude and extended intertidal zone in this bay, special focus was given to the intertidal vs subtidal habitat use patterns. Bottlenose dolphins were observed in only half of the surveyed area, with on average 1 dolphin group encountered per 100 km surveyed. All dolphin groups were seen in shallow waters <10 m deep. GLM analyses showed that especially during high tide, depth had an important effect on the dolphin encounter rate, with most dolphin groups encountered in the intertidal zone. While in the intertidal zone, most dolphin groups were observed to be engaged in surface feeding activities. The presented data indicate dolphins remained in shallow waters, and moved to the intertidal zone during high tide where they appear to find feeding opportunities. This information is believed to be of high value in understanding this population's ecological needs, and essential when aiming to improve marine conservation efforts at times of increased anthropogenic pressures in the area.

scholarly journals EFFECTS OF SEASONAL VARIATIONS ON SANDY BEACH GROUNDWATER TABLE AND SWASH ZONE SEDIMENT TRANSPORT

2014 ◽  
Vol 1 (34) ◽  
pp. 59
Author(s):  
Norasman Othman ◽  
Ahmad Khairi Abd Wahab ◽  
Mohamad Hidayat Jamal
Keyword(s):  
Sediment Transport ◽  
Seasonal Variations ◽  
Sandy Beach ◽  
Groundwater Table ◽  
Swash Zone

scholarly journals FIELD MEASUREMENTS OF BEDFORMS IN A RIP CHANNEL ON A MACRO-TIDAL BEACH

2012 ◽  
Vol 1 (33) ◽  
pp. 93
Author(s):  
Antony Thorpe ◽  
Jon Miles ◽  
Gerd Masselink ◽  
Paul Russell ◽  
Tim Scott ◽  
...  
Keyword(s):  
Sandy Beach ◽  
High Tide ◽  
Field Measurements ◽  
Rip Current ◽  
Peak Period ◽  
Migration Rates ◽  
Sand Ripple ◽  
Current Maximum ◽  
Offshore Flow ◽  
And Migration

A Sand Ripple Profiler (SRP) was deployed in a rip channel on a dissipative sandy beach to measure bedform height (∆), length (λ) and migration rate (Mr¬) throughout a macro-tidal cycle with an offshore significant wave height of 0.7 m and peak period of 10 s. At lower tidal elevations in the strong offshore flow of the rip current (maximum = 0.4 m/s) bedforms (∆ = 0.15 m, λ = 3 m) were found to migrate offshore (Mr = 0.21 m/hr). Outside of active rip current conditions (water depth (h) = >~2.5 m) bedforms were found to be of smaller scale (∆ = 0.09 – 0.12 m, λ = 1 – 1.2 m) migrating onshore at a rate of 0.35 m/hr at mid tide (h = 3.3 m) and 0.03 m/hr at high tide (h = 6.3 m). Onshore migration rates were found to increase with increased wave skewness and velocity variance.

scholarly journals Cross-Shore Suspended Sediment Transport in Relation to Topographic Changes in the Intertidal Zone of a Macro-Tidal Beach (Mariakerke, Belgium)

2019 ◽  
Vol 7 (6) ◽  
pp. 172 ◽  
Author(s):  
Evelien Brand ◽  
Lars De Sloover ◽  
Alain De Wulf ◽  
Anne-Lise Montreuil ◽  
Sander Vos ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Intertidal Zone ◽  
Field Experiments ◽  
High Tide ◽  
Laser Scanner ◽  
Quantitative Agreement ◽  
Suspended Sediment Transport ◽  
Transport Direction ◽  
Erosion And Accretion

Sediment transport is a key element in intertidal beach morphodynamics, but measurements of sediment transport are often unreliable. The aim of this study is to quantify and investigate cross-shore sediment transport and the resulting topographic changes for a tide-dominated, sandy beach. Two fortnight-long field experiments were carried out during which hydrodynamics and sediment dynamics were measured with optical and acoustic sensors, while the beach topography was surveyed with a permanent terrestrial laser scanner. Suspended sediment was generally well-mixed and currents were largest at approximately 1.5 m above the bed, which resulted in a peak in sediment transport at 1/3 of the high tide level. The mean transport direction was onshore during calm conditions (wave height <0.6 m) thanks to tidal currents and offshore during energetic conditions due to undertow. Oscillatory transport was always onshore because of wave asymmetry but it was subordinate to mean transport. The intertidal zone showed an alternation of erosion and accretion with formation of morphological features during energetic (no storm) conditionsand smoothening of the morphology during calm conditions. A good qualitative and quantitative agreement was found between the daily cross-shore suspended load and beach volume changes, especially during calm conditions.

High Tide Movements and Homing Behaviour of the Tidepool Sculpin Oligocottus maculosus

1971 ◽  
Vol 28 (3) ◽  
pp. 383-389 ◽  
Author(s):  
John M. Green
Keyword(s):  
Spatial Distribution ◽  
Intertidal Zone ◽  
High Tide ◽  
Homing Behavior ◽  
Homing Behaviour ◽  
Oligocottus Maculosus

Tagging studies show that the tidepool sculpin Oligocottus maculosus Girard shows fidelity to specific tide pools and will return to their pools when displaced. The results indicate that the navigational ability of O. maculosus is not solely dependent upon familiarity with geographical features of the intertidal zone. It is suggested that homing behavior functions as a mechanism stabilizing the spatial distribution of this species.

scholarly journals Responses of the mussel Brachidontes rodriguezii to aerial exposure: implications on growth and physiological condition

2019 ◽  
Vol 97 (7) ◽  
pp. 612-618 ◽  
Author(s):  
María Eugenia Torroglosa ◽  
Juliana Giménez
Keyword(s):  
Shell Length ◽  
Intertidal Zone ◽  
Physiological Condition ◽  
Physiological Stress ◽  
High Tide ◽  
Aerial Exposure ◽  
Intertidal Zones ◽  
The North ◽  
Calcein Am ◽  
High Intertidal Zone

The length of aerial exposure (i.e., environmental conditions) of an organism, due to daily tides, induces physiological responses. A mark–recapture field experiment was conducted in two intertidal zones (low tide and high tide) using the stain calcein AM to determine growth, as measured by shell length, of the mussel Brachidontes rodriguezii (d’Orbigny, 1842) along its vertical distribution off the north Argentinean coast. In the high intertidal zone, B. rodriguezii exhibited slower growth in shell length because of the physiological stress resulting from aerial exposure during low tides. In the low intertidal zone and during spring, B. rodriguezii exhibited faster growth in shell length. It is suggested that growth of B. rodriguezii relies on several environmental factors (temperature, photoperiod, and aerial exposure) that fluctuate according to tidal height.

Ecology and behaviour of immature Culicoides melleus (Coq.) (Dipt., Ceratopogonidae)

1972 ◽  
Vol 62 (1) ◽  
pp. 113-127 ◽  
Author(s):  
J. R. Linley ◽  
G. M. Adams
Keyword(s):  
Intertidal Zone ◽  
Laboratory Experiments ◽  
High Tide ◽  
Time Of Day ◽  
Fourth Instar ◽  
Tidal Level ◽  
Sand Surface ◽  
Tide Level ◽  
The Vertical Distribution ◽  
Incoming Tide

The distribution of the larvae and pupae of Culicoides melleus (Coq.) in a natural beach habitat in an inlet on the Florida coast was studied in relation to tidal level and time of day. Larvae and pupae were confined to the intertidal zone and these distributions were unaffected by time of day or tidal level. Distributions of younger larval instars were displaced towards the inferred area of oviposition at higher elevations on the beach. Pupae were associated with the zone at and somewhat below high tide level. Differences in the vertical distribution of larvae between 0 and 2 in. deep between dark (pre-dawn)/low tide, morning/low tide and afternoon/low tide conditions were probably associated with larval response to light and heat.In laboratory experiments with a temperature gradient, second- to fourth-instar larvae preferred the 18–25°C range, but the fourth instars were the least discriminating. Laboratory experiments with a simulated beach showed that pupae flooded on an incoming tide remained in their burrows and immediately buried themselves more deeply when waves were generated in the water; they were able to return to the surface if buried, and survived drowning for four days. Inundated areas were avoided as pupation sites. The orientation of pupae at the sand surface and their formation in burrows was related to negative phototactic responses of the pupating larvae.

scholarly journals MOSAIC PATTERNS OF THERMAL STRESS IN THE ROCKY INTERTIDAL ZONE: IMPLICATIONS FOR CLIMATE CHANGE

2006 ◽  
Vol 76 (4) ◽  
pp. 461-479 ◽  
Author(s):  
Brian Helmuth ◽  
Bernardo R. Broitman ◽  
Carol A. Blanchette ◽  
Sarah Gilman ◽  
Patricia Halpin ◽  
...  
Keyword(s):  
Climate Change ◽  
Thermal Stress ◽  
Intertidal Zone ◽  
Rocky Intertidal ◽  
Rocky Intertidal Zone

Numbers of naked amoebae inhabiting the intertidal zone of two geographically separate sandy beaches

2000 ◽  
Vol 80 (4) ◽  
pp. 731-732 ◽  
Author(s):  
Andrew Rogerson ◽  
Fiona Hannah ◽  
Gwen Hauer ◽  
Phillip Cowie
Keyword(s):  
Intertidal Zone ◽  
Sandy Beach ◽  
Sandy Beaches ◽  
Beach Sand ◽  
Cultivation Method ◽  
Future Studies ◽  
Beach Communities ◽  
Shallow Subtidal ◽  
Lower Intertidal Zone ◽  
Naked Amoebae

Numbers of naked amoebae (Gymnamoebae) inhabiting the lower intertidal zone of two sandy beaches were estimated using a novel enrichment cultivation method. Samples were collected between June and September, 1999. Beach sand at Kames Bay, Isle of Cumbrae, Scotland contained on average 2604 amoebae cm−3 while at Dania Beach, Florida, USA, sand harboured 4236 amoebae cm−3. This is the first study to focus on the abundance of naked amoebae inhabiting a sandy beach. These numbers are higher than densities generally reported for shallow subtidal sands and show that amoebae must be considered in future studies on the dynamics of sandy beach communities.

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