Tidal Migration Research Articles

Use of a mangrove estuary as a nursery area by postlarval and juvenile banana prawns, Penaeus merguiensis de Man, in Northern Australia

In the Embley River, Gulf of Carpentaria, Australia, the largest catches of the commercially important banana prawns, Penaeus merguiensis , were made on mangrove-lined, steeply sloping mud banks. The upstream limit of distribution of P. merguiensis was found to coincide with the distribution of broad bands of fringing mangrove forests but, except in the wet season, was not related to salinity levels. Although some postlarval P. merguiensis settled on all habitat types in the estuary, large catches were only taken on the mangrove-lined banks. Catches of both postlarvae and juveniles in the upstream reaches of a small creek were almost five times higher than those in the river near the creek mouth. Moreover, prawns in the 2 to 4 mm carapace length (CL) size class were poorly represented in the river but were abundant in catches in the small creek. This suggests that either the survival rate of postlarvae is highest in the upper reaches of the small creeks, or that the small prawns are migrating from the main river into the creek. As prawns increase in size above 5 mm CL it appears that they take part in daily tidal migrations from small creeks to the river and begin a gradual migration from the creeks to the river.

Barrier Island Evolution and Reworking by Inlet Migration along the Mississippi-Alabama Gulf Coast: ABSTRACT

ABSTRACT The five barrier islands along the Mississippi-Alabama coast are located 10 to 14 miles (16 to 23 kilometers) offshore and separate Mississippi Sound from the Gulf of Mexico. The barrier islands in the chain are, from east to west: Dauphin Island, Petit Bois Island, Horn Island, Ship Island, and Cat Island. The islands are low sand bodies situated on a relatively broad Holocene sand platform that extends 70 miles (113 kilometers) from Dauphin Island on the east to Cat Island on the west. The platform varies in thickness from 25 to 75 feet (7.6 to 23 meters) and rests on Holocene marine clays or on Pleistocene sediments. The barrier islands are nourished chiefly by littoral drift from sand sources to the east. The barrier island chain predates the St. Bernard lobe of the Mississippi delta complex, which began to prograde about 3,000 years ago, and continued until it was abandoned approximately 1,500 years ago. In contrast to the other islands, Cat Island at the western down-drift end of the Mississippi-Alabama barrier island chain, is characterized by more than 12 prominent east- west oriented progradational linear ridges. The ridge system of Cat Island is interpreted as a relict of an earlier stage in the life cycle of the barrier platform when there was a more robust littoral drift system and an abundant sediment supply. During the Pre-St. Bernard Delta period of vigorous sedimentation, the islands in the barrier chain probably exhibited progradational ridges similar to those now found only on Cat Island. Presently, only vestigial traces of these progradational features remain on the islands to the east of Cat Island. Unlike Cat Island, which has been protected and preserved by the St. Bernard Delta, the other barrier islands have been modified and reworked during the past 1,500 years by processes of island and tidal inlet migration, accompanied by a general weakening of the littoral drift and a reduction of the available sediment supply. The four tidal passes, or inlets, that separate the barrier islands are broad low areas in the Holocene barrier island sand platform, ranging from 3.5 to 5.8 miles (5.6 to 9.3 kilometers) in width. The water depth in the passes is generally shallow, less than 15 feet (4.6 meters), except in the tidal channels where natural depths of more than 30 feet (9 meters) are often reached. Due to the water depths reached by the tidal channels, the nearly the full thickness of the Holocene island platform east of Cat Island has likely been reworked during the migration of the islands and tidal passes. Additionally, the down-drift islands have become increasingly sediment-starved due to sediment losses in the island passes. Shoals and lobes of sand, commonly found on the north (Mississippi Sound) side of the barrier islands, are interpreted to be the remains of interchannel shoals that mark former tidal inlet positions.

Ontogeny and importance of tidal vertical migrations in the retention of larval smelt Osmerus mordax in a well-mixed estuary

Ontogeny and importance of tidal vertical migrations in the retention of larval smelt Osmerus mordax in a well-mixed estuary

The relationship of juvenile southern mole crabs Hippa australis Hale (Crustacea : Anamura : Hippidae) to surficial swash water-circulation over several diurnal spring-tide cycles during winter conditions on a micro-tidal sandy beach

The location of the southern mole crab Hippa australis Hale within the swash zone at North Beach, Western Australia, was studied with respect to tidal levels, wave run-up, beach morphology, and wave energy conditions over a 4-day period. H. australis undertake distinct tidal migrations within the ground-water resurgence zone on the sandy beachface where characteristics of the water circulation system alter with tidal fluctuations. They locate themselves high in the swash zone at low tide and low in the swash zone at high tide. Mole crabs avoid high wave energy conditions as indicated by their scarcity during storms at North Beach. Their immediate reappearance in higher number as storm surges subside further indicates that they avoid storms by burrowing deep into the substratum. The position of mole crabs at any time during the tidal cycle may be related to the opportunities of feeding in the swash zone.

Semi-diurnal variation in beachface aggradation and degradation

Sequences of morphologic change on the beachface at South Beach, Wollongong, N.S.W., were monitored for several semi-diurnal spring-tide cycles. The observations were made to establish temporal and spatial variation in the beachface response to tide, swash and groundwater interactions. It was anticipated that the sequences would differ under high and low wave energy conditions and on different parts of the same beach, where the foreshore morphology varied markedly. To test these propositions, two-dimensional beachface responses to tide, swash and groundwater level variation have been compared for two beachface profiles, one transecting the horn of a giant cusp and the other the embayment of the same cusp. The beach survey results were specified in two ways: (1) by examining the changes in sand-surface elevation at each survey point along the profiles; and (2) by transforming the survey data with a moving-axis system whose origin followed the intersection of the sea-level with the beachface over the tide cycle. In the first instance, the sequences of beach change along each profile were similar to those described from elsewhere ∗ ∗ Duncan (1964) and Strahler (1966). , although the profiles were undergoing different secular displacements. During the course of the survey, the salient was eroded and the embayment infilled. The net changes were determined by the dynamic balance of erosion versus deposition occurring with the flood and ebb of each tide cycle. Application of the moving-axis technique identified switching between erosional and depositional states in the swash zone on the salient. The swash zone changes were controlled by the tide and groundwater fluctuations. Beachface degradation began with the tide rise and terminated shortly after mid-ebb tide. Maximum degradation occurred when the beachface was most saturated, approximately 1 to 2 h after high tide. In both high and low energy conditions, the sequence of cut and fill was similar to that described in earlier work ∗∗ ∗∗ Duncan (1964). . Tidal migration of the sea-level and water-table effluent-line across the beachface established the location of the zones of erosion and deposition. Above the effluent-line, an unsaturated beach condition enhanced deposition. Below the line, the beachface was saturated and erosional conditions prevailed. The dynamic balance, given as the amount of erosion versus deposition over each tide cycle, was associated with the different levels of wave energy and sediment supply.

Biogenic and Physical Modes of Stratification and Shell Bed Formation in the Recent Intertidal Environments of Bahia la Choya, Northern Gulf of California

Fossil concentrations such as shell beds are preferred collection sites for paleontological and paleoecological data. Although ample attention has been paid to the roles and implications of physical processes in shell bed formation, the role of biogenic sediment reworking in generating shell beds has received little study.Subsurface shell beds in the Recent intertidal environment at Bahia la Choya form via three distinct processes: storm deposition, tidal channel migration, and biogenic reworking. Shell beds on the outer tidal flats are produced primarily by storm sedimentation. Lateral migration of the main tidal channel produces shell beds along the channel margins. Shell beds on the inner flats distant from the main tidal channel are generated by vertical “conveyorbelt” recycling of fine sediment by deposit feeders. Biogenic reworking concentrates shells at depth into subsurface shell beds, producing a distinct form of biogenic bedding, termed biogenic stratification.These three modes of shell bed formation leave recognizable taphonomic and sedimentologic signatures. Biogenic stratification in particular has important implications for sedimentation rates, sediment reworking, and faunal condensation in ancient strata.

Distribution and abundance of Donax serra Röding (Bivalvia: Donacidae) as related to beach morphology. I. Semilunar migrations

Donax serra Röding is unusual among intertidal dwelling Donax species in that it does not undergo tidal migrations. We examined the distribution and abundance of the D. serra population along a 200-m section of exposed sandy beach throughout a 96-day period. D. serra was shown to exhibit a semilunar pattern of movement corresponding to the spring-neap tidal cycle. These migrations keep the D. serra band in the zone of water-saturated sand close to the water table. The data also indicate that D. serra exhibits higher abundances on the flatter portions of the beach where the water flow patterns are more suitable for filter-feeding.

Updrift Migration of Tidal Inlets

Three mechanisms are responsible for tidal inlet migration in an updrift direction (counter to net longshore transport): (1) attachment of distal ebb tide delta bars to the downdrift barrier spit; (2) storm-induced breaching and subsequent stabilization to form a new inlet; and (3) ebb tide discharge around a channel bend creating a three-dimensional flow pattern which erodes the outer channel bank and accretes on the inner channel bank. The last two mechanisms can result in either updrift or downdrift inlet migration, depending on channel geometry in the bay and barrier beach configuration. The last mechanism is discussed here for the first time. Analysis of historical charts and aerial photographs, combined with an historical storm synthesis, shows that all three mechanisms are active at a natural tidal inlet along a sandy coast (Nauset Inlet, Cape Cod, MA). On a time scale of 10 years, these mechanisms were effective in producing an updrift migration of more than 2 km. Initiation of updrift migration c...

Holocene sedimentation of a wave-dominated barrierisland shoreline: Cape Lookout, North Carolina

The sedimentary record of 130 km of microtidal (0.9 m tidal range) high wave energy (1.5 m average wave height) barrier island shoreline of the Cape Lookout cuspate foreland has been evaluated through examination of 3136 m of subsurface samples from closely spaced drill holes. Holocene sedimentation and coastal evolution has been a function of five major depositional processes: (1) eustatic sea-level rise and barrier-shoreline transgression; (2) lateral tidal inlet migration and reworking of barrier island deposits; (3) shoreface sedimentation and local barrier progradation; (4) storm washover deposition with infilling of shallow lagoons; and (5) flood-tidal delta sedimentation in back-barrier environments. Twenty-five radiocarbon dates of subsurface peat and shell material from the Cape Lookout area are the basis for a late Holocene sea-level curve. From 9000 to 4000 B.P. eustatic sea level rose rapidly, resulting in landward migration of both barrier limbs of the cuspate foreland. A decline in the rate of sea-level rise since 4000 B.P. resulted in relative shoreline stabilization and deposition of contrasting coastal sedimentary sequences. The higher energy, storm-dominated northeast barrier limb (Core and Portsmouth Banks) has migrated landward producing a transgressive sequence of coarse-grained, horizontally bedded washover sands overlying burrowed to laminated back-barrier and lagoonal silty sands. Locally, ephemeral tidal inlets have reworked the transgressive barrier sequence depositing fining-upward spit platform and channel-fill sequences of cross-bedded, pebble gravel to fine sand and shell. Shoreface sedimentation along a portion of the lower energy, northwest barrier limb (Bogue Banks) has resulted in shoreline progradation and deposition of a coarsening-up sequence of burrowed to cross-bedded and laminated, fine-grained shoreface and foreshore sands. In contrast, the adjacent barrier island (Shackleford Banks) consists almost totally of inlet-fill sediments deposited by lateral tidal inlet migration. Holocene sediments in the shallow lagoons behind the barriers are 5–8 m thick fining-up sequences of interbedded burrowed, rooted and laminated flood-tidal delta, salt marsh, and washover sands, silts and clays. While barrier island sequences are generally 10 m in thickness, inlet-fill sequences may be as much as 25 m thick and comprise an average of 35% of the Holocene sedimentary deposits. Tidal inlet-fill, back-barrier (including flood-tidal delta) and shoreface deposits are the most highly preservable facies in the wave-dominated barrier-shoreline setting. In the Cape Lookout cuspate foreland, these three facies account for over 80% of the sedimentary deposits preserved beneath the barriers. Foreshore, spit platform and overwash facies account for the remaining 20%.

Tidal migrations of the littoral salt marsh snail Melampus bidentatus Say

Quantitative field observations and experiments on populations of the snail Melampus bidentatus Say revealed tidal-related shifts in their distribution within the intertidal zone of a New England salt marsh. Adult M. bidentatus were found at lower marsh levels during periods of neap tidal cycles and moved to higher ground on days of spring tides. Juveniles did not participate in these periodic migrations and remained in the middle portion of the overall M. bidentatus range, often concealed under the stems and exposed roots of marsh grasses. Some adult snails, but not juveniles, also climbed grass stems during high tides, but did so irregularly and in variable numbers. Since only one-third of the climbers went high enough to avoid flood waters, this vertical migration is unlikely to serve essential respiratory or temperature control functions. Experiments on the locomotory behavior of snails in a laboratory chamber in which humidity and slope of crawling surface were controlled complemented field observations. Wet (high relative humidity, rH) conditions induced up-slope movement at greater speeds and lower turning rates than observed in dry (low rH) conditions. Partially dehydrated (10% loss of body water) snails showed strong geotactic responses (down-slope) but moved up-slope when placed in wet conditions. Juvenile snails exhibited no preferential movement in any chamber conditions but did reduce their crawling speeds and increase their turning rates in response to dry conditions. These combined field and laboratory studies emphasize that M. bidentatus adults respond strongly to specific environmental conditions with locomotory behavior that may help reduce the risk of potentially dehydrating exposure. As is discussed, M. bidentatus possesses a number of physiological capabilities for dealing with water stress. The behavior described herein adds a behavioral adaptation of use to this air-breathing snail in persisting as one of the few resident animals in the highly variable conditions of the salt-marsh intertidal zone.

Dispersal and recruitment of blue crab larvae in Delaware Bay, U.S.A.

Results of a three-year survey of the occurrence of Callinectes sapidus larvae in the mouth of Delaware Bay indicated that stage I zoea larvae were most abundant insurface water as compared to mid-depths and near bottom. The major peak in abundance of stage I zoea larvae occurred in early August with a secondary peak in early September. Peaks in abundance of megalopae occurred five weeks after the respective peaks in zoeal abundance. Zoea stages II–VIII were not collected in the bay mouth. Results of sampling every 3 h over consecutive tidal cycles showed that stage I zoea larvae were most common in the water column on ebbing tidal currents. Megalopae were most common in the water column on flooding tidal currents, suggesting a tidally related, vertical migration. It was concluded that stage I zoea larvae are flushed from the estuary and undergo development on the continental shelf. Megalopae are then transported back to inshore waters by a combination of winds and currents and invade the estuary by means of migration into the water column on flooding tidal currents and migration to the bottom on ebbing tidal currents.

Report: London International Food and Drink Exhibition

The Banc d'Arguin in Mauritania is an area characterised by shallow waters and tidal flats with extensive seagrass beds. The aim of this study was to determine the role of the Banc d'Arguin tidal flats as a habitat and a nursery for shrimps. Shrimps were sampled in the Baie d'Aouatif in the intertidal (ponds, Zostera noltii seagrass beds and bare sediment) with a push net during high and low tide, a beam trawl during high tide and in the subtidal (Cymodocea nodosa and Zostera noltii seagrass beds) with a beam trawl during low and high tide from January to March 2002. In total, eleven shrimp species (9349 individuals) were found, the most abundant of which were Palaemon elegans, Hippolyte longirostris, H. inermis (in subtidal) and Peneaus spp., whereas Athanas nitescens, Leander tenuicornis, Palaemon adspersus, Pontophilus fasciatus, Sicyonia carinata and Processa edulis subsp. crassipes were less abundant. At high tide in the intertidal all species were mainly found in sheltered areas (ponds and seagrass) rather than in unvegetated habitats. Mark-recapture experiments showed that shrimps migrate between intertidal ponds during high tide. Densities in the subtidal were similar during high and low tide, suggesting that there is no substantial tidal migration to and from the tidal flats for any of the species. Two subtidal shrimp species seemed to prefer Cymodocea nodosa beds. A large fraction of the individuals of five shrimp species carried eggs. Ten of the eleven species caught were also found as juveniles. The results of this study, and earlier studies, indicate that many shrimp species reproduce in or near the tidal-flat area of the Banc d'Arguin. Some shrimp species, notably Penaeus kerathurus and P. notialis, are likely to use the area as a nursery, migrating offshore as adults. This suggests that the Banc d'Arguin is an important resource for commercial fishery.

Underwater television observations on the intertidal movements of shore crabs,Carcinus maenas, across a mudflat

Closed circuit underwater television observations showed that, in summer, large numbers ofCarcinus maenasperformed daytime tidal migrations up and down a small mudflat in the Menai Strait, North Wales. At the observation point, 25 m above mean low water mark of spring tides, numbers of crabs moving upshore on flood tides averaged 84 m—1of tideline, ranging from 48 to 126 m—1. Most crabs were of 20–50 mm carapace width (1 and 11 groups); none smaller than 15 mm was seen. Peak movements occurred in at least 0.5 m depth of water. Over the high tide period, most crabs were dispersed over the upper half of the mudflat where crab population densities of 1·8–2·5 m—2were indicated by diving observations.

Effects of Oyster Beds on Back-Barrier Geomorphology--a Three-Dimensional Model: ABSTRACT

Studies along the South Atlantic coastline show that the geomorphology of tidal flats and salt marshes is commonly altered or controlled by the development of Crassostrea virginica oyster mounds. Two major mechanisms for geomorphic control have been recognized. (1) The oyster mound is a long sinuous bar encompassing large parts of the tidal-flat fringe. This bar acts as a barrier, slowing and in some areas completely impeding drainage of the flat during the receding tide. The impoundment of sediment-laden water increases the rate of deposition over the flat, eventually raising the surface topography and accelerating the progradation of the fringing salt marsh. (2) An oyster mound grows perpendicular across a small tidal channel, effectively damming the channel, causing in reased rates of sedimentation. Sometimes the tidal prism of the channel has been sufficiently altered so that an initiation of lateral tidal-creek migration occurs. Migration rates up to 1 m/year have been measured. In other cases, the channel fills with a fine-grained plug. Coring of two marsh systems in South Carolina shows that oyster mounds can play an important role in the depositional history of the marsh. In areas where lateral tidal creek migration occurs, much of the stratigraphic record is dominated by channel-fill point-bar sequences. Combining modern process data with subsurface cross sections derived from over 20 cores, a three-dimensional model showing the effects of oyster mounds on the back barrier environment has been developed. End_of_Article - Last_Page 1661------------

Tidal phenomena and migration, production, and distribution of hydrocarbon pools

New problems in the migration of fluids and in the formation and distribution of hydrocarbon pools in relation to tidal phenomena are discussed in the context A.R. Kinzikeyev's paper, Effects of Earth Tides as a Factor in the Migration, Formation, and Distribution of Hydrocarbon Pools, Geologiya Nefti i Gaza, 1978, no. 5, 36-39. (JMT)

TIDAL RHYTHMS OF ACTIVITY AND PHOTOTAXIS OF AN ESTUARINE CRAB LARVA

1. Tidal rhythms in swimming speed and phototaxis were measured in stage III zoeae of the crab Rhithropanopeus harrisii. Larvae were captured in the Newport River estuary, North Carolina, and maintained under constant conditions in the laboratory. 2. Swimming speed increases during rising tide with a maximum several hours after low tide, and decreases to a minimum about 2 hr after high tide. It is argued that this pattern is the basis of the endogenous tidal vertical migration, in which the larvae ascend on rising tides and descend on falling tides. 3. The tidal rhythm in phototaxis consists of an increase in negative responsiveness which is strongest around the middle of the rising tide, and a decline to a minimum during falling tides. Positive phototaxis shows the opposite pattern. There is no convincing evidence that phototaxis participates in vertical migration. It is hypothesized that the phototactic pattern represents a tidal rhythm in a shadow response used for predator avoidance.

The sand-burrowing amphipod Amphiporeia virginiana Shoemaker 1933 in the tidal plankton

The abundance of Amphiporeia virginiana in the tidal plankton over a high energy sandy shore in southern Maine increased to maximum values 1 to 1.4 m above mean low water (MLW) with no clear evidence of a diurnal cycle affecting swimming activity. The species undergoes daily tidal migrations over the shore with swimming activity increasing just before high tide and generally peaking during ebbing tides. Results of experiments with laboratory-held animals supported these conclusions, although swimming rhythms disappeared rapidly after 24 h in the laboratory. The swimming behavior of the species assists reproductive contact of sexes that are segregated in the sand, contributes to short-term fluctuations in distribution and abundance, and assists the species in maintaining dominance on high energy sandy shores.

Tidal Vertical Migration: An Endogenous Rhythm in Estuarine Crab Larvae

Field-caught larvae of the estuarine crab Rhithropanopeus harrisii have a tidal rhythm of vertical migration when maintained in constant conditions. Laboratory-reared larvae do not show this rhythm. Endogenous tidal vertical migrations aid the retention of these planktonic larvae in estuaries near the parent populations.

Tidal movements of the macrofauna on an exposed sandy beach in South Africa

All epifaunal and shallow‐burrowing, intertidal macrofauna on an exposed sandy beach appear to undergo tidal migrations which vary in extent but are all upshore on the incoming tide and downshore on the outgoing tide during day and night. In the crustaceans this is probably endogenous rhythmic behaviour and they show increased activity at night. In the molluscs this movement is not synchronised by an intrinsic mechanism but results from behavioural responses to changing physical conditions. The large wedge clam, Donax serra, shows no tidal migrations but does show a semilunar rhythm of movement from just above mean tide level (MTL) during springs to the low tide level during neap tides.

Dynamics of Spatial Pattern for the Gastrotrich Tetranchyroderma bunti in the Surface Sand of High Energy Beaches

AbstractThis paper is a quantitative study of the spatial pattern of the intertidal gastrotrich. Tetranchyroderma bunti, and its migration pattern during a tidal cycle on three high energy beaches of Bogue Banks, North Carolina, USA. Included in the study were the macrodistribution and micro‐distribution. T. bunti is gregarious and forms a clumped spatial pattern in the sand. The four clump sizes found were 2.2, 3.3, 4.4, and 5.5 cm with a ratio of 9: 6: 4: 1, respectively. The spatial pattern of these clumps suggests that the general spatial pattern of the population in its most dense area is aggregated clumped. Field experiments show that this is a stable pattern during at least part of the low tide period, and laboratory experiments suggest that the low water content of the sand at low tide contributes to this stability by decreasing the movement of the gastrotrichs. A significant difference (p<0.05) was found in the density of the gastrotrichs parallel to the shore line, but part of this difference was due to local shifts in the spatial pattern of the population instead of a change in the longshore abundance. T. bunti showed a tidal migration pattern opposite to that of the ground water movement.