High Tide Research Articles

Dynamic emergent leaf area in tidal wetlands: Implications for satellite-derived regional and global blue carbon estimates

The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate highlights the importance of blue carbon in tidal wetlands in combating climate change. In this study, we highlight the uncertainty associated with leaf area index (LAI) estimations in tidal wetlands, specifically salt marshes, a key vegetation parameter for productivity models and Earth System Models (ESM). LAI, derived from satellite reflectance data, is linked to atmospheric carbon exchange and gross primary production (GPP) across vegetative ecosystems. However, estimating salt marsh LAI is challenging because canopy height and density vary across short distances, and tidal flooding alters the atmosphere-exposed leaf area, hereafter called emergent leaf area index (ELAI), at short time scales. Further, in tidal wetlands dominated by species such as Spartina alterniflora, canopy height and density vary across short distances. We present a novel approach for measuring spatiotemporal dynamics in tidal wetland ELAI. We modeled ELAI from vertical LAI profiles and created spatial estimates across tidal periods. We then linked ELAI with eddy covariance carbon (C) fluxes through footprint modeling and revealed correlations between emergent leaf area and C fluxes. Next, we demonstrated that ELAI can be readily estimated across 10-m spatial scales using Sentinel-2 satellite data, even during high tides (R2 = 0.89; NRMSE = 10%). Finally, we showed a common product, MODIS MYD15A2H, underestimated (20%) LAI during dry conditions but overestimated (7–93%) during high flooding. Dynamic ELAI could reduce uncertainties in satellite-derived global GPP products when developing blue carbon budgets for ecosystems threatened by accelerated sea level rise.

Study of Hydrodynamic Patterns of Tanjung Pasir Banten Waters to Support the NCICD Sea Wall Development Plan

Numerical modeling of hydrodynamics (HD) around the Tanjung Pasir Waters was carried out using MIKE 21 HD Flexible Mesh software to get the current velocity pattern conditions during the west and east monsoons. This activity is to support the NCICD sea wall construction plan. In addition, the results that will be obtained in this modeling are the conditions of the speed and direction of the current in various tidal conditions during spring and neap. The data used in this modeling include wind speed and direction, wave height, wave period, and wave direction. Based on the research that has been done, the validation value of Naotide tidal data on tidal field data is 93.8 %. HD MIKE 21 modeling results on field data have a validation value of 93.4 %. Extract points 4 and 5 which are the northernmost, have the highest current velocity values compared to the other points. In addition, when heading to the high tide phase, both spring and neap conditions, the current velocity value has the highest value.

Temporal variation of freshwater as control of mangrove in Banyuasin Estuary, South Sumatra, Indonesia

Abstract. Surbakti H, Nurjaya IW, Bengen DG, Prartono T. 2023. Temporal variation of freshwater as control of mangrove in Banyuasin Estuary, South Sumatra, Indonesia. Biodiversitas 24: 1502-1510. The Banyuasin Estuary receives much freshwater, which transports low-salinity water from upstream to the sea through the rivers that flow along the area. The interaction between the freshwater mass from the river and the highly saline seawater mass moving toward the estuary will affect the condition of the mangroves in the region. This study aims to estimate the freshwater runoff from the two main rivers (Musi River and Banyuasin River) into the Banyuasin Estuary in different seasons, at high and low tides, and their impact on the mangroves present in both estuaries. The interaction between the freshwater and seawater masses can be explained using the freshwater fraction and transect methods used for mangrove zonation analysis. This research focuses on the mouth of the Musi River and the Banyuasin River. The present study showed the influence of freshwater fraction at the mouth of the Musi River is very strong in all seasons, dominated by oligohaline and mesohaline conditions. In contrast, the mouth of the Banyuasin River is dominated by mesohaline and polyhaline conditions. Altogether, ten species of mangroves have been found in the Banyuasin Estuary. Of which, low saline tolerant species, namely Nypa fruticans and Sonneratia caseolaris, are predominant, whereas salt tolerant species, namely Avicennia marina, are predominant in the mouth of the Banyuasin River.

California coastal access damage from early winter 2022-2023 storms: A photo essay

Atmospheric rivers, “bomb cyclones,” storm waves and high tides wreaked havoc along the central California coast from San Francisco to Monterey. From 26 December 2022 to 11 January 2023, more than 10 inches of rain fell in central California (Landers 2023). During this same time period, higher high tides were 6-ft or greater for 10 of these days and 35-ft high waves were noted. Beaches, beach accesses, and coastal trails were on the front lines for storm defenses and damage. In addition to the extensive new coverage, the National Oceanic and Atmospheric Administration’s National Geodetic Survey (NOAA/NGS) collected continuous post-storm(s) airborne photography along the west coast that will be invaluable in analyzing future long-term shoreline changes (NOAA/NGS 2023). The following photos, taken soon after the storms, show some of the coastal damage near and in Monterey Bay.

Research on Seawater Intrusion Suppression Scheme of Minjiang River Estuary

Seawater intrusion in the Minjiang River estuary has gravely endangered the water security of the surrounding area in recent years. Previous studies mainly focused on exploring the mechanism of intrusion, but failed to provide a scheme for suppressing seawater intrusion. The three most relevant determinants to chlorine level, which represented the strength of seawater intrusion, were determined using Pearson correlation analysis as being the daily average discharge, daily maximum tidal range, and daily minimum tidal level. Considering the lower requirement of sample data and the ability to handle high-dimensional data, the random forest algorithm was used to construct a seawater intrusion suppression model and was combined with a genetic algorithm. The critical river discharge for suppressing estuary seawater intrusion determined using this model. The critical river discharge was found to gradually increase with the maximum tidal range, which in three different tide scenarios was 487 m3/s, 493 m3/s, and 531 m3/s. The practicable seawater intrusion suppression scheme was built up with three phases to make it easier to regulate upstream reservoirs. In the scheme, the initial reading of river discharge was 490 m3/s, and it rose to 650 m3/s over six days, from four days before the high tide's arrival to two days following it, and before falling down to 490 m3/s at the end. Verified with the 16 seawater intrusion events in the five dry years, this scheme could eliminate 75% of the seawater intrusion risk and effectively reduce the chlorine level for the remaining 25% of events.

Entrapment of harbour porpoises (Phocoena phocoena) in herring weirs in the Bay of Fundy, Canada

Harbour porpoises (Phocoena phocoena) are small coastal cetaceans vulnerable to mortality in fishing operations. Not all interactions are fatal, however, and each year many porpoises swim into and are subsequently released from herring weirs in the Bay of Fundy, Canada through a targeted release programme. This study examines catch composition, body condition, characteristics associated with mortality and factors affecting entrapment of porpoises in weirs between 1992-2001. A total of 886 porpoises were recorded in weirs during this period. A total of 657 animals were involved in attempted releases: 588 were released alive and 69 were incidentally killed during release. The remainder of the animals swam out on their own or their fates were unknown. Estimated annual mortality represents less than 0.01% of the Bay of Fundy/Gulf of Maine population and only 1.03% of its annual potential biological removal level. The number of porpoises caught in weirs varied from eight in 1996 to 312 in 2001. Of the 390 animals released with a numbered identification tag, 25 were recaptured in weirs and 4 of those porpoises entered a weir a third time. Males comprised 63.5% of entrapments. Weirs and demersal gillnets captured animals from the same population, but the weir bycatch was biased towards younger, smaller animals. Porpoises that became trapped in weirs exhibited measures of body condition similar to those killed in gillnets and by gunshot wounds in the same waters. None were considered emaciated. Mortality in weirs appeared to be random; porpoises that died during release attempts were of the same age and sex composition and body condition as the individuals that survived. The use of a specialised large-mesh seine significantly increased the probability of successful release. Observations of the stomach contents data of porpoises killed in weirs indicate that porpoises feed while trapped in weirs, but perhaps not at the same rate as animals killed in gillnets. Entrapments peaked in August, concurrent with the highest landings of Atlantic herring, the target species of the weir fishery. Based on a logistical regression model, porpoises are 3.3 times more likely to swim into a weir on a night in which high tide falls during darkness. Weir entrapments do not have a significant effect on this population, largely because of on-going efforts to release porpoises from weirs.

Dynamics of upstream saltwater intrusion driven by tidal river in coastal aquifers

For the coastal aquifers, recent research have shown that the tidal has a significant effect on saltwater intrusion in the near-shore aquifer. However, it is currently unclear how the tidal river contributes to the groundwater flow and salinity distribution in the upstream aquifer of the estuary. This study examined the effects of a tidal river on the dynamic characteristics of groundwater flow and salt transport in a tidal river-coastal aquifer system using field monitoring data and numerical simulations. It was found that changes in tidal-river level led to the reversal of groundwater flow. For a tidal cycle, the maximum area of seawater intrusion is about 41.16 km2 at the end of the high tide stage. Then the area gradually decreased to 39.02 km2 at the end of the low tide stage. More than 2 km2 area variation can be observed in a tidal cycle. Compared to the low tide stage, the area of SWI increased by 5 % at high tide stage. The SWI region was also spreading landward from the tidal river. In addition, we quantified the water exchange and salt flux between the tidal river and aquifer. When the tidal fell below the level of the riverbed, the water exchange rate was stabilized at about −1.6 m/h. The negative value indicated that the river was recharged by the groundwater. With the increasing of tidal water level, the water exchange rate gradually changes from negative to positive and reached the maximum value of 3.2 m/h at the beginning of the falling tide stage. The presence of a physical river dam can amplify the difference in water level between high and low tides, thereby enhancing the influence of a tidal river on water exchange and salt flux. The findings lay the foundation for gaining a comprehensive understanding of the tidal river on groundwater flow and salt transport in upstream aquifers.

Use of psychotropic drugs in the elderly in France: Are we condemned to remain at high tide?

Psychotropics are widely used drugs, especially in the elderly, especially in France. This, and the risks associated to their use, logically led to concerns that resulted in numerous studies, reports, and regulatory actions intending to limit this use. This review objective was to provide an overview of psychotropic use in elderly subjects in France for antipsychotics, antidepressants, and benzodiazepines and related drugs. The narrative review performed is structured in two parts. The first reminds the initial steps of psychotropic use monitoring in the general French population. The second provides information on psychotropic use in elderly in France using the latest open data released by the French Health Insurance system and processed using the dedicated DrugSurv tool developed within the DRUGS-SAFE® and DRUGS-SAFE® programs. This was completed examining the most recent studies regarding psychotropic use in elderly in France, whether they consisted in publications or reports. At least before the COVID-19 epidemic, decreases in psychotropic prevalence of use among the elderly in France could be observed, mostly for antipsychotics or benzodiazepines (e.g. antipsychotics, 2006-2013: 10.3% decrease and benzodiazepines 2012-2020: decrease from 30.6% to 24.7% in subjects aged ≥65). Psychotropic prevalence of use remained however very high overall (e.g. antidepressants, 2013: 13% in subjects aged 65-74 and 18% in aged ≥65), exceeding that of most other countries, with a significant proportion of inappropriate use (e.g. in 30% of benzodiazepine users, all ages) carrying a clearly identified risks for uncertain benefit. Initiatives have been multiplied at the national level to reduce psychotropic overuse in the elderly. The reported prevalences demonstrate their effectiveness is obviously insufficient. This limited effectiveness is not specific to psychotropics and might reside in a failure to create strong adherence to messages and recommendations. Other levels should be considered, especially regional, for interventions coupled with pharmacoepidemiologic monitoring allowing impact assessment.

Spotted Gully Shark Triakis megalopterus at Robben Island, Table Bay, South Africa

We report a sighting of a Spotted Gully Shark Triakis megalopterus at Robben Island, 7 km from the nearest mainland, in Table Bay, South Africa. The sighting was made on 18 February 2023 within an hour of high tide.

Kandungan nitrogen saat pasang dan surut di Sungai Mahakam Kota Samarinda

This study aims to determine the levels of nitrogen compounds in the Mahakam river at high and low tide, and to compare it with the quality standard East Kalimantan Timur Regulation Number 02 0f 2011 concerning Water Quality Management and Water Pollution Control. The data obtained in the field and the results of the analysis in the laboratory are displayed in the form of tables and graphs. The data is presented based on a descriptive picture to get conclusions from the results of the study, with an independent sample t-test and compared the average between the two cases. The levels of Ammonia, Nitrite and Nitrate at high tide were significantly lower than at low tide. lower than at low tide. Ammonia levels at high tide ranged from 0.382- 0.424 mg/L, and have exceeded the quality standard threshold of regional Regulation of East Kalimantan Province Number 02 of 2011. Nitrite levels at high tide range from 0.027- 0.068 mg/L and ar low tide 0.04 - 0.068 mg/L, and still meet the quality standards of East Kalimantan Province Regulation Number 02 0f 2011.Nitrate levels at high tide range from 0.89 – 1.20 mg/L and at low tide 1.00 – 1.20 mg/L, which still meets the quality standards of East Kalimantan Province Regualation No. 01 of 2011. The levels of Ammonia, Nitrite and Nitrate at high and low tide were not significantly different.

Nowcasting of Wind in the Venice Lagoon Using WRF-FDDA

The Four-Dimensional Data Assimilation module (FDDA) is used in combination with the WRF model for the analysis of two case studies of high tide (on 4 April 2019 and on 12 November 2019) that affected the Venice Lagoon in the recent past. The system is implemented in the perspective of an operational use for nowcasting of 10 m wind, which will be part of a numerical system aimed at the forecast of the sea level height in the Venice Lagoon. The procedure involves the assimilation of data from meteorological surface stations distributed within the Venice Lagoon and in the open northern Adriatic Sea in front of the lagoon, as well asthe radiosonde profiles available within the simulation domain. The two cases were selected considering that the real-time forecasts missed their evolution, and the sea level height was significantly underpredicted. The comparison of the simulated wind with the observations shows a fairly good agreement over short time scales (1–2 h) in both cases; hence, the WRF-FDDA system represents a promising tool and a possibly valuable support to the decision makers in case of high tide in the Venice Lagoon.

Hydrodynamic model approach to study the pattern of sea surface currents around the Tanjungpinang City reclamation site

This study aims to study the pattern of sea surface currents at the research site using a hydrodynamic modelling approach. Hydrodynamic models are approaches used to study large-scale and long-term patterns of sea surface currents (past, present, and future projections). Study on the sea surface currents at the research site was conducted by constructing the 2D hydrodynamics model which was simulated for 30 days to describe the pattern of sea surface current at the research site. Finite differences methods were used in solving the equation of the 2D hydrodynamic model. Validation result showed that the model has a good performance and it was relevance to in-situ measurement. The simulation results showed a significant difference in current velocity during high and low tides. Current velocity is higher at high tide (0.15-0.18 m/s) than at low tide (0.06-0.10 m/s). At high tide, current direction is dominant towards the southeast and southwest. At low tide, current direction is dominant to the north and northwest. The sea surface currents at the research site are strongly influenced by tidal conditions. At high tide, sea surface current will move towards the coast and at low tide the sea surface current will move away from the coast.

Study of Types and Production of Trap Net Fishery Fish based on Moon Phase in the Waters of Segeri District, Pangkep Regency, South Sulawesi Indonesian

The research was carried out in October-November 2020 in the waters of the Pangkep Regency. The data collected consisted of primary and secondary data, using direct observation in the field. Tidal observations were carried out in every moon phase for 2 x 24 hours. I collected data on the type and number of catches in each month’s phase. Tidal analysis using the criminal method and descriptive analysis of the types and quantities of trap net fish production (kg) and (Rp). The full moon phase is the highest tide at 185 cm and the lowest at 42 cm. The average sea level (mean sea level) is 113.5 cm. Types of trap net catch based on the moon phase in the waters of Sergei District, Pangkep Regency, identified 13 types of catches. The highest amount of fish production was obtained by the full moon phase of 100 kg, followed by the 80 kg dead moon phase, 95 kg early quarter moon, and 65 kg final quarter moon phase.

Identifikasi Kelimpahan Mikroplastik Sungai Batanghari Wilayah Nipah Panjang Kabupaten Tanjung Jabung Timur

One of the biggest environmental issues today is plastic waste. This waste cannot be avoided and continues to increase which in its decomposition takes 50-100 years and will be fragmented into smaller forms called microplastics. Microplastic measuring < 5 mm with various shapes. The people of the Nipah Panjang area dispose of plastic waste into the Batanghari River which is likely to cause microplastic content. To determine the number of microplastics, it is necessary to identify the abundance of microplastics found in the Nipah Panjang area on the Batanghari River using quantitative methods. The tool used is Planktonet mesh 150 with a diameter of 20 cm. The sampling process was carried out for one day with two samplings, namely in the morning at low tide at 09.00-11.00 WIB and in the afternoon at high tide at 15.00 WIB. The study's results were sampling in the morning at low tide with 327 microplastic particles and the highest in the afternoon at high tide, namely 443 microplastic particles. The temperature in the morning and evening ranges from 29°C - 32°C. The results showed that four types of microplastics were found, namely the type of fiber, filament, fragment, and granule. From the four locations of Sungai Air samples, the most microplastic fragments were found with a total of 353 particles, the second most were filament types with a capacity of 191 particles, the third type of fiber with a total of 186 particles, and the least types of granules with a total of 40 particles. Microplastic at low tide is lower than at high tide. The abundance of microplastics from the four sampling locations of river water is 25,666.67 particles/m3.

Tidal cycle and time of day control pH levels in coastal habitats of the western Indian Ocean: the case of Mnazi and Chwaka Bays in Tanzania

Ocean acidification, a progressive decrease in the pH and change in the carbonate chemistry of seawater caused by the uptake of carbon dioxide (CO2) from the atmosphere, is a growing crisis that threatens marine species. pH data relevant to a species’ natural habitat in the coastal waters of the western Indian Ocean (WIO) is still sparse, limiting the capacity to undertake manipulative studies to better understand the impacts of ocean acidification on marine species. This study investigated tidal and day-night pH variations in mangrove, seagrass, and coral reef habitats of the WIO by using Tanzania as a case study. The mean pH of the studied coastal habitats was highest in seagrass (8.49 ± 0.29), followed by coral reef (8.33 ± 0.06), and lowest in mangrove (8.20 ± 0.17). Seagrass habitats had the highest pH (9.06) during the day at low spring tides, mangrove habitats had the highest pH (8.45) during the day at high spring tides, and coral reef habitats had the highest pH (8.47) during the day at low tides. Seagrass habitats had the widest pH range (1.03), followed by mangrove habitats (0.54), while coral reef habitats had the narrowest range (0.23). The water with the highest pH during the day was transported to nearby mangrove habitats during incoming tides and to coral reef habitats during outgoing tides, resulting in the highest mean pH in mangrove and coral reef habitats during spring high and low tides, respectively. pH within the seagrass habitats correlated strongly and positively with changes in temperature (r=0.80), dissolved oxygen (r=0.84), and salinity (r=0.72), while pH in mangrove habitats correlated moderately and positively with dissolved oxygen (r=0.59). This study provides in-situ evidence on the pH fluctuations in the WIO’s coastal habitats over time and space, with water from seagrass habitats capable of raising the pH of water in nearby mangrove and coral reef habitats during the day, thereby potentially helping in the mitigation of the effects of ocean acidification on these habitats.

Participatory mangrove planting as a coast abration disaster mitigation effort in Pasimarannu Village, Sinjai Regency

Pasimarannu village as one of the villages experiencing coastal abrasion and threatening the settlements of residents living in coastal areas. During the high tide, several houses were submerged by sea water, and during the east and west seasons the wind was strong enough so that the high waves reached under the houses. Attention and effort are needed in anticipating the level of damage that will occur. The community service program is carried out by providing awareness and active participation of the community in protecting the coast through participatory mangrove planting. The method of implementing the activities consists of socialization and FGD on the implementation of the activity plan, Formation of Forest Farmer Groups (KTH), mangrove nurseries, participatory mangrove planting, embroidery, and maintenance, as well as program monitoring and evaluation. Technical activities involve extension workers and forestry technical personnel. The key to the success of this participatory planting is the right planting time to avoid the strong currents and waves in the east monsoon. Routine maintenance activities to anticipate and eradicate oyster pests that damage plants during the vulnerable phase, which is up to 4 months of planting.

Protecting coastal infrastructure in the face of increasing climate related pressures: A cost-benefit analysis of maintaining a tidal kayaking feature in Ireland

Climate change, the rising of sea levels and extreme weather conditions that can result in exceptional high tides and storm surges are threatening vulnerable coastal infrastructure. In this study, we investigate the recreational value of a tidal kayaking feature situated on the west coast of Ireland that is threatened in such a manner. A lock gate and sea wall, that separate the open sea from a natural sea lagoon, forms a standing wave at this kayaking site. The structure, built in the 1800s is currently in need of urgent maintenance works and the lagoon also needs dredging. By means of a travel cost model, the study derives the recreational use value of the site while a cost-benefit analysis estimates the net present value of carrying out repair works at the feature. We estimated that the consumer surplus is approximately €49,000 per year and the recreational benefits are more than three times the costs of restoring the site. The paper argues that cost-benefit analysis will be particularly important to justify funding the protection of small-scale coastal infrastructure where the benefit values to society are mainly non-market.

Effects of tidal cycle on greenhouse gases emissions from a tropical estuary

The potential effects of tidal and diel cycles on fluxes and concentrations of carbon dioxide (pCO2), methane (CH4), and nitrous oxide (N2O) along with associated biogeochemical processes remain poorly understood in tropical estuaries. The present study, based on six-hourly sampling for nine consecutive days at three locations along the salinity gradient in the Mahanadi estuary of India, revealed that the tidal forcing affected pCO2 and CH4 in the mixing zone with elevated concentrations during low tide with maximum concentrations up to 21,606 μatm and 285 μM, respectively. pCO2 increased with decrease in tidal height within low and high tide duration as well, possibly due to higher relative contribution of freshwater with high CO2. N2O, on the other hand, showed no significant variability with tidal cycle or water level fluctuation during high and low tide. Barring the offshore region, the study area was source of greenhouse gases to the atmosphere.

Where land meets sea: Intertidal areas as key‐habitats for sharks and rays

AbstractIntertidal habitats (i.e. marine habitats that are (partially) exposed during low tide) have traditionally been studied from a shorebird‐centred perspective. We show that these habitats are accessible and important to marine predators such as elasmobranchs (i.e. sharks and rays). Our synthesis shows that at least 43 shark and 45 ray species, of which 54.5% are currently threatened, use intertidal habitats. Elasmobranchs use intertidal habitats mostly for feeding and as refugia, but also for parturition and thermoregulation. However, the motivation of intertidal habitat use remains unclear due to limitations to observe elasmobranch behaviour in these dynamic habitats. We argue that elasmobranch predators can play an important role in intertidal food webs by feeding on shared resources during high tide (i.e. ‘high‐tide predators’), which are accessible and also consumed by terrestrial or avian predators during low tide (i.e. ‘low‐tide predators’). In addition, elasmobranchs are able to change the bio‐geomorphology of intertidal habitats by increasing habitat heterogeneity due to feeding activities and may also alter resource availability for other consumers. We discuss how the ecological role of elasmobranchs in intertidal habitats is being affected by the continued overexploitation of these species, and conversely, how the global loss of intertidal areas poses an additional threat to an already vulnerable taxonomic group. We conclude that studies on intertidal ecology should include both low‐tide (e.g. shorebirds) and high‐tide (e.g. elasmobranchs) predatory guilds and their ecological interactions. The global loss of elasmobranch predatory species and intertidal habitat provides additional compelling arguments for the conservation of these areas.

Hydrocarbon production reduces natural methane seeps in the Santa Barbara channel

Abundant natural hydrocarbon seepage in the Santa Barbara Channel includes large amounts of gas, mainly methane. Numerous seeps are focused along a faulted anticlinal axis where in 1982 ARCO placed two large (900 m2 each) steel gas capture tents on the seabed adjacent to Platform Holly. The seep rate into the tent at high tide is about 5 percent less compared with low tide (2 m tidal range). An earthquake in 2013 (M = 4.8) did not affect seepage rates into the steel tents, indicating that gas was not released by fault dilation. The CO2 and H2S content of the captured gas are anomalously low compared to typical Holly gas due to bacterial and sea water-gas interaction at the seep tent.Platform Holly production had an overall effect of reducing gas seepage into the tents over time. Wells beneath the tents at 1-km depth had a much greater influence on the seepage rate than more distal wells. The nearby wells had a direct effect on seepage rate when they were put on production (seepage decreased) versus shut in (seepage increased). The response time was within hours, indicating a direct hydraulic connection between the reservoir at 1 km subsea and the seabed. Permeability of the approximate 1-km fault pathway between the reservoir and the seep tent is calculated to be about 3 × 10−14 m2(30 millidarcys). Gradually, the seep rate declined from peak flow in 1990 (4.5 × 104 m3 dy-1) to less than 7.1 × 103 m3 dy−1 in 2013. In June of 2013, a horizontal well was completed high on the structural anticline between Platform Holly and directly beneath the seep tents. Within three weeks of turning on this new well, seepage into the tents completely ceased, ending more than 30 years of natural methane seepage captured by the tents.