Low Tide Conditions Research Articles

Satellite-derived bathymetry using Sentinel-2 in mesotidal coasts

Coastal zones are strategic environments of high socioeconomic, political, and ecological value, with over half of the world’s population residing within 200 km of the coast. This proximity highlights their vulnerability to extreme events, which are exacerbated by global changes, leading to significant coastal impacts such as erosion, flooding, and ecosystem services deterioration. Consequently, efficient and operational methodologies for continuous monitoring are urgently needed to face these challenges. Bathymetric data are essential for understanding coastal dynamics, yet traditional data collection methods are often constrained by logistical challenges and high costs. Spaceborne remote sensing techniques offer significant advantages over traditional ground-based methods, particularly in terms of cost-effectiveness and operational efficiency. Over the last half-century, different Satellite-derived bathymetry (SDB) methodologies have been developed; however, challenges still persist. In this research, we applied a robust SDB methodology to three different study sites: Cíes Islands, Baiona Bay, and Vao beach within the Ría de Vigo, Galicia (NW Spain). These areas offer diverse and complex mesotidal environments to test for the very first time the methodology's efficacy. SDB was retrieved with a median absolute error (MedAE) ranging from 0.35 m to 1.55 m for depths up to 14 m. Results with different data source were evaluated, obtaining MedAE for nautical charts ranging from 0.46 m to 1.55 m. The precision between the data sources were quite close. In addition, multi-image composite was generated using images coinciding with both low tide (LT) and high tide (HT) conditions across the three zones. The lowest MedAE values were consistently obtained in images classified as LT (0.46 m) corresponding to Vao area. The results highlight the potential of nautical charts as a reliable source of calibration data for SDB, confirm the effectiveness of multi-image and switching models to correct artifacts and turbidity, considering tidal effects, improving single image approaches, and leverage visible bands for precise depth retrieval under varying conditions.

Assessing sediment CO2 effluxes in the coastal ecosystem of North Sumatra, Indonesia

Coastal wetlands including mangrove play a vital role in regulating the local and global carbon cycle. Coastal areas contribute greatly to the carbon exchange process due to the complex interactions that occur between the atmosphere, land, and oceans. One of the important components in coastal carbon dynamics is CO2 gas exchange between soil, water and the atmosphere. This study aims to assess CO2 efflux across various land covers (namely natural mangrove, restored mangrove, and converted mangroves to oil palm and aquaculture pond) in the coastal areas of North Sumatra Province, and analyze the effect of sea tides and ebbs on the rate of CO2 efflux and their connection with the number and area of macrozoobenthos burrows. We applied direct sampling by using the static closed chamber method attached to portable CO2 analyzer. The mean of CO2 efflux in natural mangrove forest land covers was 866±585 mgCO2/m2/h during low tide conditions and 1137±792 mgCO2/m2/h during high tide conditions, followed by oil palm plantations at 760.71±341 mgCO2/m2/h, restored mangroves during low tide of 575.24±326 mgCO2/m2/h and 597.11±180 mg CO2/m2/h during high tide conditions, and the lowest was recorded in ponds at 588.55±358 mgCO2/m2/h. Further, we observed that tidal conditions affect the magnitudes of CO2 efflux in natural and restored mangrove forests, and we did not observe similar pattern in oil palms and ponds since these land covers were not influenced by regular tidal input. We also observed that no significant relationship between the number and area of macrozoobenthos burrows and CO2 efflux. Our findings suggest that CO2 effluxes in coastal wetlands are highly dynamic and presumably driven by complex factors and therefore, understanding their magnitudes and drivers requires extensive measurement covering large spatial and temporal scales.

Diversity of Gastropods in The Mangrove Forest Area of Ujung Kulon National Park

Various kinds of reseources in coastal areas are very important for us to maintain sustainability. We can find coastal area with varios kinds of ecosystems in Ujung Kulon National Park. This study aims to determine the diversity of gastropods in the mangrove forest area of Ujung Kulon National Park. Sampling used the line transect method and the purposive sampling method with low tide conditions. Sampling was carried out at three stations which are divided into three transects at each station. The transect line was drawn along 50 m with each transect made 5 plots with a size 1 x 1 m2 with a distance between plots of 10 m. This research was held in May-June 2021. The data analysis includes the index values of diversity, dominance, evenness, and abundance. The results of the gastropod obtained consist of 20 species from 7 different families so that diversity index value were included in the medium category with the highest diversity index value owned by station 1 with a diversity index value of 2,03 and the lowest diversity index value owned by station 3 with a value of 1,56. The gastropod abundance index value has an average value of 273 ind/m2.

Changes of physiological traits on red chili pepper (Capsicum annum L.) exposed by short-term waterlogging

Abstract Tropical riparian wetland known as non-tidal lowland is potential land for agriculture, especially for vegetable cultivation such as red chili pepper (Capsicum annum L.). Transitional period (dry to rainy season) has a chance for red chili pepper cultivation in the field (at low tide conditions), but has risk of experiencing dynamic water table to waterlogging in early rainy season. The aim of this research was to determine the effects of physiological traits of red chili pepper exposure on short-term (4 days) waterlogging. This study was done at the Tropical Crop Science Laboratory, Kagoshima University, Japan. The experiment was designed as a completely randomized factorial design. The first factor was control/field capacity and waterlogging (entire growing media was submerged). The second factor was chili variety, consisting of Laris and Romario. Treatments began 14 days after transplanting, lasted four days, then followed by seven days of recovery. The results of this study showed that there were changes in photosynthetic characters between before waterlogging, after waterlogging and after recovery time, between control and waterlogging, and also between Laris and Romario. Photosynthetic and transpiration rates decreased sharply under waterlogging in after waterlogging, but increased in after recovery period on Laris, opposite on Romario. Changes occur were associated with the decline in stomatal conductance and chlorophyll fluorescence as a response to waterlogging stress. Laris as a resistant variety has the ability to recover under short-term stress conditions, so it needs to be further developed for cultivation in tropical riparian wetlands.

Contrasting Methane Seepage Dynamics in the Hola Trough Offshore Norway: Insights From Two Different Summers

AbstractThis study investigates the temporal variations in methane concentration and flare activity in the Hola trough (offshore Norway) during May 2018 and June 2022. Between these time periods, methane seep activity exhibits 3.5 times increase, as evidenced by hydroacoustic measurements. As the seep area in the Hola trough is constantly within the hydrate stability zone, the observed increase cannot be attributed to migration of its shallow boundary due to temperature increase. However, a combination of low tide conditions resulting in a lower sediment pore pressure and a bottom water temperature increase resulting in a lower methane solubility is likely to explain the increase in the number of seeps observed in June 2022. The hypothesis of tide influence is supported by data collected from a piezometer deployed and recovered during the cruise showing that the tidal effect was observed 3 m below the seafloor. Despite the numerous methane seeps detected, methane concentration and gas flow rates near the seafloor were low (<19 nM and <70 mL min−1, respectively) compared to other areas with methane seep activity. This is likely due to strong currents rapidly dispersing methane in the water column. Sub‐seafloor investigations identified pathways for gas migration in methane seep areas, influenced by topography. This study provides valuable insights into the temporal dynamics of methane concentrations, flare activity, and gas distribution in the Hola trough, contributing to our understanding of offshore methane dynamics in the region.

Tidal Characteristic Analysis Utilizing Radar Tide Gauge in Cirebon Seawater

Radar-based tide gauges are one approach in measuring water level offering easier installation and maintenance. Tidal data recording that has been done commonly applies tide staff or pressure tide gauge. In this study, a radar tide gauge was installed at Cirebon port, northern part of Java island, to determine the tidal characteristics in Cirebon seawaters. Water elevation data was recorded every 15 minutes from July 2022 to November 2023. The tidal component is calculated using least squares method while the tidal type is determined using the Formzahl number. The dominant tidal component known consists of semidiurnal component i.e. M2, S2, N2, K2, 2N2; diurnal component, K1, O1, P1, Q1, J1, TAU1; and shallow water component SSA components with a height of 11.98, 5.58, 2.91, 2.11, 1.45, 11.80, 3.89, 6.11, 2.08, 1.56 and 3.11 (in cm), respectively. Tidal type in the study area is mixed type prevailing Semidiurnal. The tidal range is around 0.8-1 m high with high tide conditions at 6.00-9.00 and 18.00 - 21.00, while low tide conditions are within 11.00 - 14.00 and 01.00 - 04.00. Elevation height calculation based on datum is done by combining the tidal components. Tidal measurement data using radar can be an alternative data to support and complement data recorded in Cirebon and may become a consideration for development and other maritime activities.

Kajian Kualitas Air Laut dan Sebaran Indeks Pencemaran di Pesisir Utara Kecamatan Palang-Tuban pada Musim Kemarau

The northern coastal area of ​​Palang Sub-District is a densely populated area in the Tuban district with high differentiation of economic activities. The large population and heterogeneous community activities on the northern coastal of Palang Sub-District have the potential to become a source of pollution which results in a decrease in seawater quality. The research aim is to analyze seawater quality on the north coast of Palang Sub-District based on seawater quality parameters and the spatial distribution of the pollution index. It is hoped that this research can help local governments to monitor and control water pollution in the area. Sea water sampling was carried out in the dry season for 2 days at high and low tide conditions. This research analyzes the concentration values ​​of BOD, COD, NO3-, TSS, detergent, oil & grease, pH, temperature, and Total coliform compared to seawater quality standards of PP RI No. 22 of 2021 Appendix VIII on Marine Biota. The spatial distribution of the water quality pollution index is the result of interpolation using the Inverse Distance Weighted (IDW) method from the results of measuring test parameters. The Pearson Correlation statistical test was carried out to determine the level of correlation between the parameters selected in determining water quality. The results of the research show a decline in the quality of the northern coastal waters of Palang-Tuban District with several parameter concentration average values ​​exceeding the quality standards, namely pH = 6.9 (QS = 7.0-8.5); TSS = 29.2 ppm (QS= 20 ppm); Nitrate = 0.4 ppm (QS = 0.06 ppm), BOD5 = 54.8 ppm (QS= 20 ppm), COD = 112.5 ppm (QS= 100 ppm). The water quality status shows that the water conditions are moderately polluted (ST1A), lightly polluted (ST1B-ST5B), and good conditions (ST4C & ST5C). Controlling and reducing the pollution load entering coastal waters needs to be carried out to prevent the quality of coastal waters from decreasing further. One of them is by creating wastewater treatment at every fishing port and fish auction.

Spatial and Temporal Deposition Rate of Beach Litter in Cadiz Bay (Southwest Spain)

This study explores the spatial and temporal distribution of beach litter accumulation rates at seven sites in Cadiz Bay, Southwest Spain, during October 2022 (i.e., autumn) and March 2023 (i.e., spring). Beach litter was collected during low tide conditions at the strandline during two series of 10 consecutive daily surveys. The main aim of this paper is to comprehensively analyze the influence of seasonality and hydrodynamic and wind patterns on litter abundance and composition. In October, 4199 items (22.58 kg) were recorded, increasing to 4634 items (22.68 kg) in March. Overall, the average litter abundance remained relatively consistent but notable variations were observed at different beach locations. Plastic litter was the most abundant in the total litter amount with 71.13% and 88.39% in October and March, respectively. Litter categories increased from 90 to 107 from October to March and the top 10 litter categories included cigarette butts (1746 in autumn and 514 in spring), plastic fragments (985 and 339) and plastic packaging (297 and 211). Statistical analyses showed no significant seasonal impact on litter quantities but confirmed seasonal variations in litter types. For instance, cigarette butts were more abundant in October, i.e., in autumn, as they are linked to the intensive use of beaches during the summer period (June–September), while wet wipes were prevalent in March, i.e., in spring, because they are associated with an increase in wastewater and river discharges recorded during the late autumn and winter months (November–February). No clear correlations were found between litter quantity and wave height, but specific patterns emerged at exposed and sheltered beaches. The findings provide valuable insights for optimizing coastal clean-up efforts with customized strategies. Further investigations are needed to fully understand the relationships between litter and environmental factors.

Spatio-temporal composition of aquatic birds community in Juluapan Lagoon, Colima, Mexican Central Pacific

Introduction: Aquatic birds (AB) are usually associated with wetlands, which provide refuge, food, and/or nesting sites for resident and migratory species. Despite their ecological importance, there is little knowledge on AB in some tropical environments, such as those found on the Colima coast. Objective: To investigate the spatial and temporal composition of the AB community in Juluapan Lagoon, Colima, Central Mexican Pacific. Methods: Monthly counts were conducted between June 2017 and May 2018 during low-tide conditions to record habitat use by AB. Species richness and bird counts were obtained to compare sampling areas; mean richness and number of individuals were compared between seasons. Results: We detected 53 species and 5 750 individuals. The highest species richness and relative abundance values were obtained in winter at the lagoon area farthest from the connection with the marine system, where anthropogenic activity is lower. Diversity was greater in zones 2 and 3 in spring, summer, and fall. Muddy flats were the most used environment, and the most frequent activity was resting. Nesting activity was only recorded in the middle of the lagoon at the mangrove during spring. Shorebirds and waders were the most dominant groups in the bird community of the Juluapan lagoon. Conclusions: This coastal wetland is a site of great biological importance for aquatic birds; thus, conservation measures should be implemented, and there should be a continuous study of the effects of anthropogenic pressure.

Modelling of ocean currents and distribution of total suspended solids in Citarum River estuary

The Citarum River is an important river in West Java, which empties into the Java Sea carrying large suspended sediment concentrations. The purpose of this study is to examine the interaction of current patterns and distribution of total suspended solids (TSS) in the Northwest and Southeast Monsoons using hydrodynamic Modelling. The flow model and TSS used were 2-dimensional models with the OpenFlows FLOOD software. The ocean tide model results were validated using the Root Mean Square Error (RMSE) method with a value of 0.10. The current velocity in the West and East monsoons ranges from 0.07 - 0.35 m/s. Currents flow north and northeast during high-tide conditions and move south and southwest during low-tide conditions in both seasons. The movement of TSS was influenced by the current patterns. The highest concentration of TSS is in the Northwest Monsoon at low tide, which was in the range of 560–575 mg/L. The lowest TSS concentration was in the Southeast Monsoon during high tide conditions, ranging from 80 to 120 mg/L. The high concentration of TSS in the Northwest Monsoon was influenced by higher rainfall, with an average in January and only 23.2 mm/day while in the Southeast Monsoon it is only 7.8 mm/day.

BIOMIMICRY OF NATURAL REEF HYDRODYNAMICS IN AN ARTIFICIAL SPUR AND GROOVE REEF FORMATION

An artificial spur-and-groove (SAG) reef formation designed to perform as a submerged breakwater was studied. Not only do natural SAG reefs effectively attenuate waves, but they also create important circulation within the system that encourages the success of corals and the overall ecosystem. Modular components were developed and imported into the CFD software FLOW-3D® HYDRO to test the wave-structure interaction while adjusting the geometry of the structure, wave conditions, and depth due to tidal changes in environmental conditions similar to Moloka’i, Hawaii. Results showed highest wave height reduction with larger wave heights as well as lower submergence during low tide conditions.

WAVE TRANSMISSION AND DISSIPATION BY HYBRID (VEGETATED WITH MANGROVE) BREAKWATERS

In recent years a group of studies for coastal protection (Hashim and Catherine (2013), Maza et al. (2018), Tomiczek et al. (2020), among others) have been carried out to determine drag coefficients in mangrove forests due to ocean waves. Following the mangrove hybrid platform concept by Tagaki (2019), and actual projects such as the mangrove rehabilitation site in the Jakarta Fishing Port, the main objective of this study was to propose and test a hybrid structure capable of controlling wave energy via breaking and dissipation. The experimental tests focused on determining the rates of the wave energy distribution (reflection, transmission and dissipation) due to the presence of an afforested mangrove zone in the upper part of the breakwater. A fixed-bottom small-scale model was tested under normal and extreme marine regimes. The prototype dimensions of the breakwater are total height 5.70 m, crest width 10 m, seaside slope 2:1 (H:V) and leeward slope (1.5:1). The barrier is composed of a rigid bottom built of artificial elements (cubipods) and a long crown intended to be vegetated (with red mangroves, for example). The rationale behind this configuration is to provide ecosystem services by an artificially built mangrove forest protected by the rigid bottom. The experimental program consisted of 54 experiments divided into 7 groups corresponding to regular and irregular waves, mean and extreme and high and low tide conditions. Other variables of interest were the density and spatial distribution of mangroves, such as core materials.

Estuarine Mixing Patterns and Siltation Impact: A Case Study of Air Rami River Estuary

Investigating the Air Rami River Estuary in Mukomuko Regency, this study examines the influence of siltation on mixing characteristics within the estuarine environment. The research aims to discern and characterize mixing patterns in the estuary, employing direct field measurements conducted during both tide and low tide conditions in March 2023. Descriptive and quantitative analyses reveal notable salinity variations, with tidal conditions exhibiting a peak salinity of 10 ppt at a depth of 2 meters, and low tide conditions showing a maximum salinity of 5 ppt at 1.5 meters depth. Temperature variations are also observed, with tide conditions reaching 31.5°C and low tide conditions at 27.2°C. Calculation of the estuary number indicates a perfectly mixed stratified estuary mixing type, characterized by an estuary number magnitude of 0.53. These findings offer insights into estuarine mixing dynamics and their implications for coastal ecosystems.
 Highlight:
 
 Siltation Impact: Investigates the influence of siltation on mixing patterns in the Air Rami River Estuary, Mukomuko Regency.
 Salinity and Temperature Variations: Describes notable variations in salinity and temperature during tide and low tide conditions, providing insights into estuarine dynamics.
 Estuary Number Analysis: Utilizes the estuary number to classify estuarine mixing type, revealing a perfectly mixed stratified estuary with implications for coastal ecosystems.
 
 Keyword: Estuarine Mixing, Siltation Influence, Salinity Variations, Temperature Dynamics, Coastal Ecosystems

CARBON STORAGE POTENTIAL OF DOMINANT MANGROVES IN WESTERN INDIAN SUNDARBANS

The Indian Sundarbans are noted for luxuriant mangrove diversity that is known to scrub carbon dioxide from the atmosphere. Precise estimation of the biomass of these species is necessary for evaluating the carbon storage pattern in the mangroves of the lower Gangetic belt. The plant biomass estimation was carried out for an average of 25 trees in 15 (10 m × 10 m) plots from the intertidal mudflats of Chemaguri (southeast portion of Sagar Island) in low tide conditions from 10th to 15th September 2022. The estimated biomass was of the order Sonneratia apetala > Avicennia alba > Avicennia marina > Excoecaria agallocha > Avicennia officinalis. The stem, branch, and leaf biomass of each species were converted into carbon by multiplying with a factor of 0.45 as per the standard procedure. The deviations observed in the results obtained from both studies call for the standardization of the process.

Infragravity waves at the Hambantota port located in the North Indian Ocean

Infragravity (IG) waves are the primary cause of harbor oscillations. The Hambantota port located in the North Indian Ocean is taken as an example to study the IG waves in the vicinity and interior of a complex-shaped real harbor and to reveal the energy transfer of IG waves toward the harbor. The research employs a combination of in-situ wave measurement and numerical simulations conducted using the spectral wave model WAVEWATCH III. The latter could provide a long-term estimation of the level of IG wave energy over a broad geographical region, though it cannot reflect the complex mechanism of IG waves near/at the shore. Results indicate that, at the sensor near the harbor entrance, the free IG wave heights HFIG generally exceeds the bound IG wave height HBIG. However, during energetic sea states (significant wave height HS > 2.5 m in this study), HBIG increases significantly and occasionally exceeds HFIG. The spatial distributions of HS, HBIG, and HFIG indicate that the narrow continental shelf surrounding Sri Lanka has a marginal effect on attenuating swell energy. Consequently, the Hambantota port experiences a substantial impact from both swell and accompanying IG waves. If solely considering the maximum acceptable HS, the downtime for large ships would be greatly underestimated. The process of wave propagation into the harbor enables the energy transfer from bound IG waves to free IG waves that finally excite harbor oscillations. Albeit the tidal range is low, the tidal level has a noteworthy impact on harbor oscillations. The IG spectral density during low tides is generally greater than that during high tides due to the enhanced nonlinear interactions of short waves under low-tide conditions.

Hydrodynamic Model due to Reclamation in Lamong Bay

PT. Teluk Lamong Terminal is one of the busiest port terminals in Indonesia. Such conditions require the development of the facility area for reclamation. This reclamation can potentially change the seabed’s contours and current patterns in the Lamong bay area of Surabaya. Therefore, the Author will conduct a research study to determine the impact of reclamation on the speed and current pattern of the existing and post-reclamation conditions in Lamong bay, Surabaya. This research conducted numerical modeling with Delft3D software. The simulation results show that the current pattern at the highest tide in the existing and reclamation models tends to have a dominant current direction from east to the northwest in the Madura strait. In contrast, some currents from the Madura strait are deflected into the Lamong bay area. On the other hand, during the lowest low tide conditions, both existing and reclamation conditions, the current pattern has a dominant direction coming from the northwest to the east, and the current in the Lamong bay area tends to exit or towards the Madura strait. There is an increase or decrease in current velocity when reclamation is carried out in each tidal condition. The highest increase in current velocity occurs at high tide with a value of 0.02 m/s, while the highest decrease in current velocity occurs at the high tide of 0.13 m/s. At the lowest ebb conditions, the highest current speed increase is 0.12 m/s, and the highest current velocity decrease is 0.03 m/s.

Monitoring Water Quality in Ballona Lagoon, Los Angeles, California: Nitrate Level Fluctuation in Low and High Tide Condition

Monitoring Water Quality in Ballona Lagoon, Los Angeles, California: Nitrate Level Fluctuation in Low and High Tide Condition

Relationships between Organic Matter Content in Seawater and Sediment in the East Coast of Bengkalis Island, Riau

Organic matter is one of indicators of environmental fertility in both land and aquatic ecosystem. In the coastal area, the content of organic matter in a certain amount can be useful for aquatic biota, but it can also cause a disturbance if the amount exceeds the assimilation capacity of the waters. This study aims to determine the organic matter content in the water column and sediment at high and low tide conditions in the waters of the East coast of Bengkalis Island as well as to determine their relationships. The study was carried out by survey method where samples and data were collected directly in the field and then were taken to the laboratory for further analysis. The results showed that the mean organic matter content in the seawater was lower at high tide (17.38 mg/L – 25.28 mg/L) than at low tide (29.63 mg/L – 35.55 mg/L), whilst in sediments the organic matter content at high tide conditions was also lower (2.28% - 5.37%) compared to low tide (3.46% - 8.62%). The sediment of the east coast of Bengkalis Island was dominated by mud type (53.62 - 93.94 %). The organic matter content in seawater and sediment showed a strong correlation with r value of 0.730 both during high tide (Y= -1.423 + 0.271X) and also during low tide (Y= -14.912 + 0.615X with r value of 0.844), respectively. Further study is still needed to provide a comprehensive understanding on the sustainable environmental condition of the east coast of Bengkalis Island as it is one of the important fishing ground.

Wave overtopping at near-vertical seawalls: Influence of foreshore evolution during storms

This work presents the results of an investigation on how wave overtopping at a near-vertical seawall at the back of a sandy foreshore is influenced by sequences of erosive storms. The experiments were carried out in the Large Wave Flume (GWK) at Leibniz University, Hannover (Germany). The tested layout consisted of a near-vertical 10/1 seawall and a sandy foreshore with an initial 1/15 slope. Three sequences of idealised erosive storms were simulated. Within each storm both the incident wave conditions and still water level were varied in time to represent high and low tide conditions. Each sequence started from a 1/15 configuration and the beach was not restored in between storms. The measurements included waves, beach profile, wave overtopping volumes. The profile of the beach was measured after each sea state tested.Wave overtopping at each stage of the tested storms was significantly influenced by bed changes. This was linked to the measured evolution of the beach. Measurements showed that a barred profile developed quickly at the start of each sequence, and scour developed at the toe of the structure during high water level conditions, while accretion or partial backfilling developed during low water level conditions. Due to these processes, the position of a sea state in the tested sequence is shown to be an important factor in determining the wave overtopping volume. Remarkably, when a weaker idealised storm followed a more energetic one, nearly the same level of overtopping was recorded. This is explained by the foreshore erosion, leading to increased water depths and wave heights at the toe of the structure. This finding allows to quantify and to explain the variability of wave overtopping in storms following one another at intervals shorter than the recovery time of the foreshore.

The influence of stochastic temperature fluctuations in shaping the physiological performance of the California mussel, Mytilus californianus.

Climate change is forecasted to increase temperature variability and stochasticity. Most of our understanding of thermal physiology of intertidal organisms has come from laboratory experiments that acclimate organisms to submerged conditions and steady-state increases in temperatures. For organisms experiencing the ebb and flow of tides with unpredictable low tide aerial temperatures, the reliability of reported tolerances and thus predicted responses to climate change requires incorporation of environmental complexity into empirical studies. Using the mussel Mytilus californianus, our study examined how stochasticity of the thermal regime influences physiological performance. Mussels were acclimated to either submerged conditions or a tidal cycle that included either predictable, unpredictable or no thermal stress during daytime low tide. Physiological performance was measured through anaerobic metabolism, energy stores and cellular stress mechanisms just before low tide, and cardiac responses during a thermal ramp. Both air exposure and stochasticity of temperature change were important in determining thermal performance. Glycogen content was highest in the mussels from the unpredictable treatment, but there was no difference in the expression of heat shock proteins between thermal treatments, suggesting that mussels prioritise energy reserves to deal with unpredictable low tide conditions. Mussels exposed to fluctuating thermal regimes had lower gill anaerobic metabolism, which could reflect increased metabolic capacity. Our results suggest that although thermal magnitude plays an important role in shaping physiological performance, other key elements of the intertidal environment complexity such as stochasticity, thermal variability and thermal history are also important considerations for determining how species will respond to climate warming.