Regular Tides Research Articles

Invasive Vaucheria aff. compacta (Xanthophyceae) and its distribution over a high Arctic tidal flat in Svalbard

The high Arctic Svalbard tidal flat ecosystem is impacted by global warming, which could allow invasion by additional species with changes in the environment supporting their growth. The transport of additional species to Svalbard could be aided by an increase in the numbers of people traveling there. Anthropogenic activities related with global warming create opportunities for organisms to move across previously isolated regions, thus advancing biotic homogenization and extinctions. Our study focused on essential quantitative and qualitative information about the occurrence of widespread mats of the invasive siphonaceous yellow-green alga Vaucheria aff. compacta in the Adventfjorden tidal flat. We outline the present ecological state of V. aff. compacta mats (land cover estimation) and discuss the origin and future development of this microphytobenthic community. Phylogenetic analyses based on rbcL genes confirmed that the studied alga is closely related to V. compacta, inside the section Piloboloideae. With the help of a drone mapping survey, we estimated that V. aff. compacta area cover was about ca 231.1 m2 ( ± 10.55%, n = 11) across the drone mapped tidal flat area of 2475 m2. We confirmed that invasive V. aff. compacta is a coastal cosmopolitan species widely disseminated on shores in both hemispheres. Invasive V. aff. compacta is an important component of the Adventforden sea-land ecotone, which affects large-scale changes within the intertidal system, stabilizes the sediment coming in with the regular tides and protect the seashore ecosystem against erosion. As a result of global warming in the Arctic, invasive V. aff. compacta facilitates the greening of the Arctic.

Newcastle disease sero and viro-prevalence in rural poultry in Chittagong, Bangladesh

Bangladesh experiences some of the highest malnutrition rates in the world, and efforts are being made to increase food security and overall health status. One of the largest constrains on increasing food security is endemic diseases among livestock and poultry populations. Newcastle Disease (ND) is one of these viral endemic diseases reducing food security. However, the sero- and viro-prevalence of ND has not been thoroughly studied in rural poultry in Bangladesh. Knowledge of farm management practices and their effect on ND sero and viro-prevalence is needed before interventions can occur, and efforts to improve the endemic state of ND cannot begin without a baseline study. This cross-sectional study randomly sampled 129 rural households with 245 chickens for the sero-prevalence and active infection rate of rural chickens in two selected upazilas (sub-districts) of the Chittagong district. ELISA was used for the detection of sero-prevalence, and cloacal samples were analyzed for ND presence using one-step RT-PCR. The aims of this study were to describe farmer demography, determine the ND sero-prevalence at the household and individual chicken level, estimate the proportionate ND prevalence at the individual chicken level, determine potential risk factors for ND sero-prevalence at the household level, and determine challenges farmers face with household chicken farming. The overall household level ND sero-prevalence based on ELISA was 31.8% (41/129) (95% CI: 23.9–40.6%), whereas the overall bird level ND sero-prevalence based on ELISA was 21.2% (52/245) (95% CI: 16.5–26.8%). ND prevalence based on RT-PCR was 12.5% (4/32) (95% CI: 3.5–29.0%). The odds of ND sero-positivity was significantly higher in farms belonging to Rangunia than in farms belonging to Anowara with an odds ratio (OR) of 7.8 (95% CI: 3.3–18.6%). The odds of ND sero-positivity was significantly lower in poultry house cleaning frequency of once or twice weekly compared with once daily cleaning (OR = 0.3; 95% CI: 0.1–0.8%). High cleaning frequency may produce excessive stress on poultry predisposing them to infection. Poultry rearing is different between Anowara and Rangunia. Anowara (coastal) scavenging areas become restricted because of regular tide flow allowing small fishes and other aquatic animals to be the dominant scavengers in Anowara. The incoming tide also removes viral reservoirs such as feces and dead birds that may otherwise be readily accessed by healthy chickens.

INSIGHT ANALYSIS ON DYKE PROTECTION AGAINST LAND SUBSIDENCE AND THE SEA LEVEL RISE AROUND NORTHERN COAST OF JAVA (PANTURA) INDONESIA

Land subsidence and the sea level rise is newly well known phenomenon around northern coast of Java Indonesia (PANTURA). The occurrence of land subsidence at least recognize at the first of the city or urban area development, while the sea level rise was recognize from several last decades corresponds to the global warming. Following the both phenomena, tidal inundation (in Javanese they call it “Rob”) is now becoming another newly well known phenomenon along PANTURA. In the recent years the tidal inundation comes not only at a high tide but even at the regular tide in some area. Sea level rise and the land subsidence are considered as the causes deriving the occurrence of tidal inundation. Dykes have been built against tidal inundation around PANTURA (e.g. in Jakarta, Blanakan, Pekalongan, Semarang, and Demak). Nevertheless, since the land subsidence and the sea level rise are believed to be continuing through times, insight analysis on these dykes “protector” is necessary. How long the dyke would effectively protect the land area would be highlight in this paper.

Optimum Water Quality Monitoring Network Design for Bidirectional River Systems.

Affected by regular tides, bidirectional water flows play a crucial role in surface river systems. Using optimization theory to design a water quality monitoring network can reduce the redundant monitoring nodes as well as save the costs for building and running a monitoring network. A novel algorithm is proposed to design an optimum water quality monitoring network for tidal rivers with bidirectional water flows. Two optimization objectives of minimum pollution detection time and maximum pollution detection probability are used in our optimization algorithm. We modify the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm and develop new fitness functions to calculate pollution detection time and pollution detection probability in a discrete manner. In addition, the Storm Water Management Model (SWMM) is used to simulate hydraulic characteristics and pollution events based on a hypothetical river system studied in the literature. Experimental results show that our algorithm can obtain a better Pareto frontier. The influence of bidirectional water flows to the network design is also identified, which has not been studied in the literature. Besides that, we also find that the probability of bidirectional water flows has no effect on the optimum monitoring network design but slightly changes the mean pollution detection time.

Approaching Russian History from European Seas

Approaching Russian History from European Seas Ryan Tucker Jones (bio) Lars Elenius, Hallvard Tjelmeland, Maria Lähteenmäki, and Alexey Golubev, eds., The Barents Region: A Transnational History of Subarctic Northern Europe. 518pp. Oslo: PAX, 2015. ISBN-13 978-8253036519. 349.00 kr. Michael North, The Baltic: A History, trans. Kenneth Kronenberg. 448pp. Cambridge, MA: Harvard University Press, 2015. ISBN-13 978-0674970830. $22.95. Michael Pye, The Edge of the World: A Cultural History of the North Sea and the Transformation of Europe. 360pp. New York: Pegasus Books, 2014. ISBN-13 978-1681772066. $17.95. Russian history, despite efforts such as Kritika’s, remains largely stuck within national or, at best, imperial and comparative frameworks. Few Russian historians have engaged with new trends in transnational histories, much less the sea-centric histories that have reshaped national histories around the Pacific, Atlantic, and Indian oceans.1 As Julia Leikin noted in a recent review for this journal, a few historians have begun to explore Russian relationships to the ocean, but the conversation remains at its beginning.2 The three works under review here suggest an alternative entry into this type of history. Scholars of neighboring countries, regions, and seas are increasingly incorporating Russia in their surveys, in recognition of the fact that Russia has long been [End Page 203] active in various European maritime spaces. As such, these books offer an intriguing avenue into Russian history, one that allows overlooked regions, stories, and people to come to the forefront in ways usually foreclosed by national histories. They also possess the potential to normalize Russian history by stressing Russian similarities to European historical trajectories, shaped by long-standing interaction and the leveling action of the regular tides of shared seas. Not all seas are the same, though. The North Sea, the Baltic, and the Barents, the subjects of three new books, all share high latitudes and convoluted shorelines inhabited by diverse peoples, but the similarities end there. While the North and Barents seas are bathed by a warm Gulf Stream, the Baltic is frozen for much of the year. The first two seas’ fisheries are also much richer. But such ecological characteristics and the environmental histories they helped shape are not the subjects of these books. This, in my opinion, is a missed opportunity to argue for the particular value of sea-based histories and leaves many important connections between Russia and Europe unexplored. An environmentally informed approach, for example, has been taken by scholars of the Pacific (e.g., Paul D’Arcy’s The People of the Sea), the Atlantic (Jeffrey Bolster’s The Mortal Sea), and the Indian Ocean, in the process uncovering entirely new historical narratives for new communities of humans and others.3 The three books under review here focus instead on the well-established but still fruitful themes of contact and convergence. This focus produces important insights for Russian history, though to varying degrees in each work. In general, the earlier each book’s chronological center of gravity, the less it has to say about Russia. Each book also varies in its commitment to a focus on the sea, with some telling parallel histories around a common center and others honing in on the maritime connections themselves. Taken together, they should alert Russian historians to the possibilities offered by the histories of seas, as well as some of the limitations of approaching the subjects without grappling seriously with the ocean itself. [End Page 204] Michael Pye’s The Edge of the World takes the strongest sea-centric approach to history. He claims that such an approach is actually the best way to recapture the viewpoint of his subjects, mostly the people of Northern Europe in the centuries after the fall of the Roman Empire and before the Renaissance. For them, there was no meaningful distinction between ocean and land, no “seaside” as an intervening space of leisure and barrier to the impact of far-off strangers. This is a world that many think of as the “Dark Ages,” but that Pye would prefer to call a “long morning” of modernity. Instead of darkness and isolation, the period was actually characterized by “constant exchange over water” and...

Tidal inundation (“Rob”) investigation using time series of high resolution satellite image data and from institu measurements along northern coast of Java (Pantura)

Tidal inundation (in Javanese they call it “Rob”) is now becoming a well known phenomenon along northern coast of Java Indonesia (Pantura). The occurrence of tidal inundation was recognized at least in the early 2000 and even earlier. In the recent years the tidal inundation comes not only at a high tide but even at the regular tide in some area across Pantura. In fact in location such as Pondok Bali, north of Blanakan, north of Pekalongan, north of Semarang and north west of Demak, seems those areas are sinking to the sea through times. Sea level rise and land subsidence are considered as main factors deriving the occurrence of this tidal inundation. We were using time series of high resolution satellite image data and insitu data measurements to mapping the tidal inundation along northern coast of Java. All available data from google data satellite archives (year 2000- recent years) and any available sources being analyze together with field surveys tagging and also from media information. As a result we can see the tidal inundation are taking place in Tanggerang, Jakarta, Bekasi, Cilamaya, Pondok Bali, Blanakan, Indramayu, Cirebon, Brebes, Tegal, Pemalang, Pekalongan, Kendal, Semarang, Demak, Gresik, Surabaya, Sidoarjo and Pasuruan.

조력발전소 가동 후 시화호 내 조간대의 면적 변화

− The intertidal area in Lake Sihwa formed after operation of Sihwa-Lake tidal power plant and the change of the area in Lake Sihwa by period were analyzed. For computation of the intertidal area, remote sensing techniques were applied and high resolution Digital Elevation Model (DEM) was generated with root mean square (rms) error 14.4 cm. The intertidal area was 165.1 km in 1910s, 115.2 km in 1991 before completion of Sihwa dyke, 5.6 km in 2010 during the period on operation of sluice gate, and 20.3 km in 2013 after operation of Sihwa tidal power plant. Intertidal in Lake Sihwa was nearly dissipated after completion of Sihwa dyke, but significantly increased with operation of Sihwa tidal power plant from April 2012 as developing a regular tide environment and increasing of sea water flux. The re-formation of tidal flat of Sihwa Lake is an uncommon case. This study that precisely analyzed on the area of artificially formed Sihwa tidal flat would be applicable for management and making conservation plan.

Effects of Sea Level Variation on Biological and Chemical Concentrations in a Coastal Upwelling Ecosystem

Oscillations in sea level due to meteorological forces related to wind and pressure affect the regular tides and modify the sea level conditions, mainly in restricted waters such as bays. Investigations surrounding these variations and the biological and chemical response are important for monitoring coastal regions mainly where upwelling shelf systems occur. A spatial and temporal database from Quick Scatterometer satellite vector wind, surface stations from the Southeast coast of Brazil and surface seawater data collected in Anjos Bay, Arraial do Cabo city, northeast of Rio de Janeiro State were used to investigate the meteorological influences in the variability of the dissolved oxygen, nutrients, meroplankton larvae and chlorophyll-a concentrations. Multivariate statistical approaches such as Principal Component Analysis (PCA) and Clustering Analysis (CA) were applied to verify spatial and temporal variances. A correlation matrix was also verified for different water masses in order to identify the relationship between the above parameters. A seasonal variability of the meteorological residual presents a well-defined pattern with maximum peaks in autumn/winter and minimum during spring/summer with negative values, period of occurrence of upwelling in this region. This lowering of the sea level is in accordance with the increasing of nutrients and meroplankton larvae for the same period. CA showed six groups and an importance of the zonal and meridional wind variability, including these variables in a single cluster. PCA retained eight components, explaining 64.10% of the total variance of data set. Some clusters and loadings have the same variables, showing the importance of the sea-air interaction.

Strategies of post-larval dispersal in non-tidal soft-sediment communities

Considering the relative significance of different dispersal rates and strategies is key for a better understanding of the scale and potential thresholds of benthic recovery processes. Despite our increased understanding of post-larval dispersal in tidal areas, our knowledge of post-larval dispersal potential is very limited for non-tidal systems, for example in the Baltic Sea, where dispersal has not previously been quantified in soft-sediment communities. For non-tidal systems the absence of regular tidal-mediated currents would suggest that post-larval dispersal potential might be limited. In this study a combination of traps was used to quantify post-larval dispersal across a wind exposure gradient in a non-tidal system. Traps allowed for a comparison of species either emerging from the sediment, being transported in sediment bedload, being transported in the water column or settling from the water column. Results from this study provide the first evidence that also in the Baltic Sea, a non-tidal system, benthic species disperse in relative proportions distinctly different from the relative composition of the resident community. A variety of post-larval dispersal strategies with species-specific differences were observed. Dispersal in the water-column might be comparatively less important in the Baltic Sea where tidal currents are absent. The majority of epifaunal species represented in the ambient community were also recorded within all dispersal modes, whereas infaunal species were less common. This suggests that, in the absence of regular tides, infaunal dispersal may be more stochastic and dependent on wind-induced waves and currents exceeding a long-term average. Post-larval dispersal was also found to be modified by the local hydrodynamic regime. Our results highlight the importance of different post-larval dispersal strategies for connectivity in soft-sediment communities in non-tidal systems.

Modeling the effects of tidal resuspension and deposition on early diagenesis of contaminants

In order to better understand the effects of tidal resuspension on contaminant cycling in coastal waters, coupled physical and biogeochemical 1-D time and depth dependent numerical models were developed. The physical model calculates sediment resuspension and deposition in response to imposed tidal current forcing and passes time series of erosion rate, deposition rate, suspended sediment load, and shear velocity to the biogeochemical water quality model. The water quality model simulates interactions between a water column, a resuspendable floc layer, and the underlying sediments through multiple resuspension and deposition cycles induced by regular tides. It includes advection and diffusion of both particulate and dissolved contaminant phases, organic carbon biodegradation, and linear-reversible contaminant sorption. Pyrene and particulate organic carbon cycling were simulated simultaneously for this study. The model was used to explore the responses of relatively clean sediments to contaminated input loadings under different levels of hydrodynamic forcing. Model results confirm influences of resuspension found in previous field and model studies, and show some unexpected effects on porewater fluxes. The results indicate that tidal resuspension 1) accelerates organic carbon degradation rate in the water column; 2) affects porewater fluxes by increasing mass transport, but decreasing the concentration difference between the water column and sediments, with unexpected results; 3) decreases accumulation (burial fluxes) in the sediments; 4) prolongs particle residence time in the water column and allows greater diagenesis and sorption/desorption to take place. Sensitivity analyses using a Monte Carlo simulation technique indicate that sediment porosity is the most critical parameter for the model, indicating further development and testing. Enhancing the prognostic skill of the model will require comparison to specific data sets from laboratory experiments and field measurements, but it is clear that resuspension may influence the sites and rates of organic matter mineralization in shallow environments and therefore affect distributions of particulate organic carbon and organic contaminants.

Plant zonation in irregularly flooded salt marshes: relative importance of stress tolerance and biological interactions

Summary 1 Most studies of salt marsh plant zonation have been at middle to high latitudes of the northern hemisphere, in euhaline or periodically hypersaline marshes with regular tides. In this study, we examined plant zonation in an irregularly flooded marsh in southern Brazil. Pore water characteristics were compared in four vegetation zones across a marsh elevation gradient. Reciprocal transplants between vegetation zones and removal experiments were performed to examine species interactions in low and mid marshes. 2 There was no distinctive gradient of physical stress across the elevation of irregularly flooded low and mid marshes. Moreover, the three dominant plants, Spartina alterniflora, Spartina densiflora and Scirpus maritimus, were able to grow across the entire elevation gradient, i.e. within zones normally occupied by the other species. The only exception was Spartina alterniflora, which was strongly limited by selective herbivory by the crab Chasmagnathus granulata in the Scirpus maritimus zone. 3 Although intra- and interspecific competition reduced growth of all three species, no competitive hierarchy was found in any vegetation zone. 4 These results suggest that, as in tidal marshes of the north hemisphere, competition is important in structuring salt marsh plant communities. In contrast, however, plant zonation in irregularly flooded marshes cannot be explained by displacement of competitive subordinates to physically stressful habitats. The roles of founder effects and selective herbivory in such marshes therefore merits further investigation.

Endogenous swimming rhythms of juvenile blue crabs, Callinectes sapidus, as related to horizontal transport

The blue crab Callinectes sapidus settles and metamorphoses in areas of aquatic vegetation in estuaries. Crabs in the first–fifth instar stages (J1–5) then emigrate from these areas by walking on the bottom or pelagic dispersal throughout estuaries. The present study was designed to characterize the timing of this migration pattern relative to the light–dark and tidal cycles. Field sampling in Pamlico Sound, NC, USA indicated that J4–5 juveniles were most abundant in the water column during the night. J4–5 juveniles were collected from Pamlico Sound in an area near Oregon Inlet that has semi-diurnal tides, a Mid-Sound area where tides are weak, and on the West side where regular tides do not occur. Crabs from all three sites had a circadian rhythm in which they swam up in the water column during the time of darkness in the field. Peak swimming consistently occurred at about 0300 h, but was not related to the timing of the tidal cycle. Similar results were obtained for juvenile crabs from an adjacent estuary having semi-diurnal tides. Dispersal at night reduces predation by visual predators, and allows early juvenile blue crabs to disperse planktonically from initial settlement sites.

Effects of embryonic salinity exposure on larval development in two populations of the estuarine crab Chasmagnathus granulatus Dana, 1851 (Crustacea: Brachyura)

Summary Life cycles of crabs include embryos, larvae, juveniles and adults that may inhabit different habitats and, consequently, cope with differing environmental cues. Embryos and adults of many estuarine crabs must tolerate diluted water, whereas their oceanic planktonic larvae live under constant salinity. The goal of this study was to investigate the effects of low salinity experienced during the embryonic phase on the survival and growth of larvae reared at low and high salinities. The observed effects of salinity on development (larval survival, developmental duration and first crab size) were compared between two populations (Mar Chiquita Lagoon, 37°45'S, and San Antonio Bay, 40°72'S) of Chasmagnathus granulatus, a semi-terrestrial estuarine crab of the southwestern Atlantic. We observed interpopulational differences in low salinity tolerance of embryos and larvae which may have been related to environmental differences between habitats. The strong effect of wind on the tides and the irregular influx of freshwater cause salinity at Mar Chiquita to be variable, both in time and space, in an unpredictable way. Embryos and larvae from this lagoon tolerated low salinities but their responses varied among individuals. Embryonic acclimation to low salinity here seems likely. Crabs in San Antonio Bay, on the contrary, experienced high and constant salinities and regular tides, and their embryos did not tolerate low salinities. Low salinity tolerance would not have an adaptive advantage in this area.

Rates of Sediment Accumulation in a Tidal Freshwater Marsh

ABSTRACT Rates of sediment accumulation were determined for a Delaware River tidal freshwater marsh utilizing radiometric, palynological and sediment flux estimating techniques plus historical reviews. All techniques showed good agreement, indicating that tidal freshwater marshes are capable of preserving evidence of processes and events that have shaped the estuary through time. Prior to 1940, the marsh was a slowly accreting swamp accumulating material at the rate of 0.04 cm yr-1 prior to colonization of the region in the late 1600s and a somewhat more accelerated rate of 0.12 cm yr-1 prior to the introduction of regular tides in 1940. Between 1940 and 1988 average rates of accumulation ranged between 1.04 and 1.38 cm yr-1, being highest near the tidal channe . During the period 1954-65, rates averaged 1.67 cm yr-1 due to increased storm activity. Since 1966, storm activity has decreased and sediment accumulation rates have averaged 0.97 cm yr-1, reflecting these changes. The current average rate of accumulation is four times the rate of sea-level rise for this region of the estuary. It is hypothesized that sediment accumulation will continue to exceed sea level rise until the marsh surface approximates mean high water.

RHYTHMS IN LARVAL RELEASE BY AN ESTUARINE CRAB (RHITHROPANOPEUS HARRISH)

Ovigerous females of the crab Rhithropanopeus harrisii were collected subtidally, and their rhythms in larval release monitored under constant conditions in the laboratory. Larvae from a single crab are generally released as a burst lasting less than 15 minutes. Larval release by crabs from an estuary lacking regular tides mainly occurs in the 2-h interval after sunset and is not related to coastal tides, which suggests a circadian rhythm. This rhythm can be entrained on an altered light-dark cycle. Larval release by crabs from an estuary with semi-diurnal tides begins at high tides and continues for 2 hours, suggesting a circatidal rhythm. Significantly more releases occur during the night. Crabs from the estuary without regular tides change from a circadian to a circatidal rhythm after being in the estuary with semi-diurnal tides. Alternatively, crabs from the estuary with semi-diurnal tides change to a circadian rhythm when exposed to a light-dark cycle and non-tidal conditions in the laboratory. Thus ...