Shallow Coastal Waters Research Articles

Cephalopoda (Mollusca) of the Colombian Caribbean Sea

The cephalopod fauna in Colombian Caribbean waters is poorly known. This work gives an overview of the species found in the area. For elaborating this list, the most relevant natural history collections where the material of the area’s is material is deposited were consulted, identifications were verified compared with type material and original descriptions and redescriptions. In the Colombian Caribbean Sea 48 cephalopod species are present in different environments, represented in 17 families and 33 genera. There is one Spirula, seven sepiolids, 21 squids, and 19 octopod species. Most animals are from shallow coastal waters.

Dynamics of Cetacean Mixed-Species Groups: A Review and Conceptual Framework for Assessing Their Functional Significance

Numerous species of cetaceans have been recorded in mixed-species groups (MSGs). By forming groups with individuals of different species, cetaceans may reduce predation risk, improve foraging, and gain social benefits. Most accounts of cetacean MSGs, however, are descriptive and little is known about their functions. Furthermore, research has been hindered by inconsistent use of terminology and the lack of a conceptual framework to guide investigations. We reviewed the cetacean literature to compare how MSGs have been termed and defined, to assess their characteristics, to evaluate what is known about their potential functions, and to provide directions for future study. In total, we reviewed 203 studies reporting observations of cetacean MSGs. These MSGs involved 54 different species, predominantly delphinids, that formed 216 different species pairs with varied morphologies and levels of relatedness. Cetacean MSGs occurred across the globe, from tropical to cold temperate seas, from shallow coastal waters to the open ocean, and varied in characteristics such as group size and frequency of occurrence. Only 27 of the reviewed studies proposed and discussed the potential functions of cetacean MSGs, suggesting reduced predation risk (5 species pairs), improved foraging (17 species pairs), and social benefits (12 species pairs) as the main drivers. In most cases, however, the factors that drive the formation of cetacean MSGs remain unknown. Amongst the reviewed studies, MSGs were referred to by various terms, often with no explicit definitions. To reduce this inconsistency, we recommend that future studies use only the termmixed-species groupwhich we define as individuals of two or more species found in close spatial proximity due to mutual or unreciprocated attraction derived from evolutionary grouping benefits. There were also few structured investigations to confirm MSG occurrence and to analyse their potential causes and consequences. To facilitate the study of cetacean MSGs, we developed a conceptual framework that establishes diverse approaches to, firstly, distinguish MSGs from chance encounters and aggregations and to, secondly, investigate their potential functions. This is necessary if we are to advance this field of study and improve our understanding of the role that MSGs play in species and community ecology.

Performance Assessments of Hurricane Wave Hindcasts

Landfalling tropical cyclones (TC) generate extreme waves, introducing significant property, personal, and financial risks and damage. Accurate simulations of the sea state during these storms are used to support risk and damage assessments and the design of coastal structures. However, the TCs generate a complex surface gravity wave field as a result of the inherently strong temporal and spatial gradients of the wind forcing. This complexity is a significant challenge to model. To advance our understanding of the performance of these models on the eastern seaboard of the United States, we conduct an assessment of four hindcast products, three based on WAVEWATCH-III and the other using the Wave Modeling project, for six major landfall TCs between 2011–2019. Unique to our assessment was a comprehensive analysis of these hindcast products against an array of fixed wave buoys that generate high quality data. The analysis reveals a general tendency for the wave models to underestimate significant wave height (Hs) around the peak of the TC. However, when viewed on an individual TC basis, distinct Hs error patterns are evident. Case studies of hurricanes Sandy and Florence illustrate complex Hs bias patterns, likely resulting from various mechanisms including insufficient resolution, improper wind input and source term parameterization (e.g., drag coefficient), and omission of wave–current interactions. Despite the added challenges of simulating complex wave fields in shallow coastal waters, the higher resolution Wave Information Study and National Centers for Environmental Prediction (ST4 parameterization only) hindcasts perform relatively well. Results from this study illustrate the challenge of simulating the spatial and temporal variability of TC generated wave fields and demonstrate the value of in-situ validation data such as the north Atlantic buoy array.

Evidence on Otolith Structure and some Ecological Features of Three Small Foraging Species along the Southern Black Sea Coast

In this study, we aimed to describe otoliths to provide information about the stomach contents of three small foraging species and to contribute to the currently limited biological and ecological evidence about the species. Seasonal experimental bottom trawl surveys were conducted along the shelf areas of the Kızılırmak-Yeşilırmak and Melet Rivers to collect investigation materials which were abundant in the bycatch composition of the target catch. The information about body size measurements, abundance values, depth, season, and locality of samplings was recorded for further evaluations. Otolith shapes were defined as discoidal to ovate for the Aphia minuta, discoidal for the Pomatoschistus marmoratus, and square for the Arnoglossus kessleri. The mean length and weight values of the Aphia minuta, which was abundant along shallow coastal waters (0-30 m), were significantly different between localities and sampling season, but no difference was found between depth ranges. Pomatoschistus marmoratus, whose distribution varied significantly between depths and seasons had dense distributions along with the depth range of 30-60 m. Arnoglossus kessleri was most abundant along with the depth range of 0-30 m and had no samples in depths of over 60 m. It was found that the mean values of length and weight of this species were only significantly different among seasons but similar over the depth ranges and localities.

Trace Metals Do Not Accumulate Over Time in The Edible Mediterranean Jellyfish Rhizostoma pulmo (Cnidaria, Scyphozoa) from Urban Coastal Waters

Jellyfish as food represent a millennial tradition in Asia. Recently, jellyfish have also been proposed as a valuable source of protein in Western countries. To identify health risks associated with the potential human consumption of jellyfish as food, trace element accumulation was assessed in the gonads and umbrella tissues of the Mediterranean Rhizostoma pulmo (Macri, 1778), sampled over a period of 16 months along the shallow coastal waters a short distance from the city of Taranto, an area affected by metallurgic and oil refinery sources of pollution. Higher tissue concentrations of trace elements were usually detected in gonads than in umbrella tissue. In particular, significant differences in the toxic metalloid As, and in the metals Mn, Mo, and Zn, were observed among different tissues. The concentrations of vanadium were slightly higher in umbrella tissues than in gonads. No positive correlation was observed between element concentration and jellyfish size, suggesting the lack of bioaccumulation processes. Moreover, toxic element concentrations in R. pulmo were found below the threshold levels for human consumption allowed by Australian, USA, and EU Food Regulations. These results corroborate the hypothesis that R. pulmo is a safe, potentially novel food source, even when jellyfish are harvested from coastal areas affected by anthropogenic impacts.

The features of the coastal fronts in the Eastern Guangdong coastal waters during the downwelling-favorable wind period

A coastal front was detected in the eastern Guangdong (EGD) coastal waters during a downwelling-favorable wind period by using the diffuse attenuation coefficient at 490 nm (Kd(490)). Long-term satellite data, meteorological data and hydrographic data collected from 2003 to 2017 were jointly utilized to analyze the environmental factors affecting coastal fronts. The intensities of the coastal fronts were found to be associated with the downwelling intensity. The monthly mean Kd(490) anomalies in shallow coastal waters less than 25 m deep along the EGD coast and the monthly mean Ekman pumping velocities retrieved by the ERA5 dataset were negatively correlated, with a Pearson correlation of − 0.71. The fronts started in October, became weaker and gradually disappeared after January, extending southwestward from the southeastern coast of Guangdong Province to the Wanshan Archipelago in the South China Sea (SCS). The cross-frontal differences in the mean Kd(490) values could reach 3.7 m−1. Noticeable peaks were found in the meridional distribution of the mean Kd(490) values at 22.5°N and 22.2°N and in the zonal distribution of the mean Kd(490) values at 114.7°E and 114.4°E. The peaks tended to narrow as the latitude increased. The average coastal surface currents obtained from the global Hybrid Coordinate Ocean Model (HYCOM) showed that waters with high nutrient and sediment contents in the Fujian and Zhejiang coastal areas in the southern part of the East China Sea could flow into the SCS. The directions and lengths of the fronts were found to be associated with the flow advection.

Microplastic fibers in the gut of highly consumed fish species from the southern Caspian Sea

This study assesses the frequency, distribution, characteristics, and chemical composition of microplastics (MPs) in the gut of highly consumed fish species, namely leaping mullet (Chelon saliens), common carp (Cyprinus carpioi), and Caspian kutum (Rutilus caspicus), in the southern Caspian Sea biome. Fibers are found to be the only shape of MPs. Black MPs and polystyrene, polypropylene, and polyethylene terephthalate polymers are dominant. MP frequency is highest in leaping mullet's gut, while kutum specimens exhibited the lowest MP frequency, reflecting that leaping mullet is a neritic species and thus highly exposed to MP influx in shallow coastal water, while the other species are benthopelagic. The estimated condition index reflected a significant difference between the species, implying that MPs may pose adverse health impacts on leaping mullet and common carp, with no undesirable effect on Caspian kutum. No significant relationship exists between biological parameters and the MP frequency in the fish gut.

Peculiarities of the Pontogammarus robustoides (Amphipoda, Gammaridae) Adaptive Reactions to the Water Temperature Increasing in the Model Ecosystem – Microcosm

The crustaceans’ family Gammaridae populations’ adaptive reactions with a water temperature increasing to the critical values were studied in the model ecosystem – the microcosm. The experiment included investigation of such indexes as population dimensional composition, precopulatory activity, number of oviparous females, embryogenesis duration, and energy metabolism at the different phases of thermocycle. Obtained data revealed optimal and critical for gammarid’s viability temperature conditions of environment. It is assumed that under conditions of climate change, when water temperature sharp fluctuations take place, in the Kyiv reservoir (Dnipro River, Ukraine) coastal shallow water crustacean’s family Gammaridae components of the invertebrates associations the structural and functional changes are expected. Temperature increasing to the critical values will promote the animals migration processes intensification; incapable of this animals will perish. Gammarids with ability to migrate in direction of areas with more favorable for their viability conditions will have a significant advantage.

Production of methane and gaseous compounds by surface microbial activity in a small pockmark field, Dunmanus Bay, Ireland

Marine pockmarks are globally widespread seabed depressions, conventionally thought to be formed by the accumulation and expulsion of microbial and thermogenic gas. However, other putative fluids and processes have been implicated in pockmark formation and gas escape to the atmosphere may be underestimated. Given the complex spectrum of aquatic settings, morphologies and sizes, there may also exist a spectrum of physical, chemical and biological processes that form pockmarks. Pockmarks in shallow coastal waters are now understood to be widespread, but the influence of physical dynamics (e.g. tides, storms, etc.), terrestrial processes and anthropogenic activities add considerable spatiotemporal complexity and uncertainty to our understanding of these features. Here, we revisit a field of small (ca. 2 m diameter), shallow (<1 m depth) pockmarks in Dunmanus Bay, Ireland. The presence of muddy surface sediments overlying sand in the pockmarked area indicates that gas accumulation within fine-grained surface sediments contributes to formation of the features. Previous work indicates that CH4 is an important seepage fluid in Dunmanus and neighbouring bays. However, based on evidence from multiple surveys, we observe considerable spatiotemporal complexity, and the transient nature of the gas within sediments points to the potential for fluids other than traditional microbial or thermogenic CH4, migrating from sources tens to hundreds of metres below the seafloor. We observed atypical porewater profiles where millimolar concentrations of H2S concentrations are observed in surface sediments in the absence of SO42− depletion, together with NH4+ build-up from ammonification of sedimentary organic matter. Archaeal methanogens, anaerobic methanotrophic archaea and SO42--reducing Deltaproteobacteria co-occur in surface sediments in the pockmark field and NMR revealed the presence of non-competitive substrates for methanogens. We hypothesize that in-situ methanogenesis and production of other volatile metabolites besides CH4 (e.g. CO2, dimethyl disulfide) from microbial degradation of organic matter are potential gaseous fluids and could contribute to the formation of small pockmarks.

Sperm chemotaxis in marine species is optimal at physiological flow rates according theory of filament surfing.

Sperm of marine invertebrates have to find eggs cells in the ocean. Turbulent flows mix sperm and egg cells up to the millimeter scale; below this, active swimming and chemotaxis become important. Previous work addressed either turbulent mixing or chemotaxis in still water. Here, we present a general theory of sperm chemotaxis inside the smallest eddies of turbulent flow, where signaling molecules released by egg cells are spread into thin concentration filaments. Sperm cells ‘surf’ along these filaments towards the egg. External flows make filaments longer, but also thinner. These opposing effects set an optimal flow strength. The optimum predicted by our theory matches flow measurements in shallow coastal waters. Our theory quantitatively agrees with two previous fertilization experiments in Taylor-Couette chambers and provides a mechanistic understanding of these early experiments. ‘Surfing along concentration filaments’ could be a paradigm for navigation in complex environments in the presence of turbulent flow.

Photo-identification comparison of four Indo-Pacific humpback dolphin populations off southeast China.

Indo-Pacific humpback dolphins (Sousa chinensis) inhabit shallow coastal waters of the Indo-Pacific region including southeast China, with at least 6 putative populations identified to date in Chinese waters. However, the connectivity among these populations has not yet been fully investigated. In the present study, we compared and cross-matched photographic catalogs of individual dolphins collected to date in the Pearl River Delta region, Leizhou Bay, Sanniang Bay, and waters southwest of Hainan Island, a total of 3158 individuals, and found no re-sighting of individual dolphins among the 4 study areas. Furthermore, there was a notable difference in the pigmentation pattern displayed by individuals from these 4 regions. We suggest that this may be a phenotypical expression of fine-scale regional differentiation among humpback dolphin groups, possibly distinct populations. Given the considerable conservation management implications it may carry (e.g. definition of management units), further research is much needed.

Global Trends in Air‐Water CO2 Exchange Over Seagrass Meadows Revealed by Atmospheric Eddy Covariance

AbstractCoastal vegetated habitats like seagrass meadows can mitigate anthropogenic carbon emissions by sequestering CO2 as “blue carbon” (BC). Already, some coastal ecosystems are actively managed to enhance BC storage, with associated BC stocks included in national greenhouse gas inventories. However, the extent to which BC burial fluxes are enhanced or counteracted by other carbon fluxes, especially air‐water CO2 flux (FCO2) remains poorly understood. In this study, we synthesized all available direct FCO2 measurements over seagrass meadows made using atmospheric Eddy Covariance, across a globally representative range of ecotypes. Of the four sites with seasonal data coverage, two were net CO2 sources, with average FCO2 equivalent to 44%–115% of the global average BC burial rate. At the remaining sites, net CO2 uptake was 101%–888% of average BC burial. A wavelet coherence analysis demonstrated that FCO2 was most strongly related to physical factors like temperature, wind, and tides. In particular, tidal forcing was a key driver of global‐scale patterns in FCO2, likely due to a combination of lateral carbon exchange, bottom‐driven turbulence, and pore‐water pumping. Lastly, sea‐surface drag coefficients were always greater than the prediction for the open ocean, supporting a universal enhancement of gas‐transfer in shallow coastal waters. Our study points to the need for a more comprehensive approach to BC assessments, considering not only organic carbon storage, but also air‐water CO2 exchange, and its complex biogeochemical and physical drivers.

Learning from Synthetic Data: Enhancing Refraction Correction Accuracy for Airborne Image-Based Bathymetric Mapping of Shallow Coastal Waters

Learning from Synthetic Data: Enhancing Refraction Correction Accuracy for Airborne Image-Based Bathymetric Mapping of Shallow Coastal Waters

Characterizing the three‐dimensional distribution of schooling reef fish with a portable multibeam echosounder

AbstractMultispecies schools of small planktivorous fishes are important constituents of reefs and coastal infrastructure; however, determining the extent and distribution of these schools is challenging. Here, we describe a novel use of a low‐cost portable multibeam echosounder from a small vessel, which can concurrently measure detailed bathymetry and the distribution of mid‐water targets with high spatial accuracy, regardless of light availability or water clarity. Fish abundance and biomass are not easily quantified by multibeam echosounders, so we developed a new metric for delineating the gridded horizontal distribution of school thickness, and assessed the metric's efficacy by examining its correlation with mean volume backscattering strength derived from a calibrated 38 kHz split‐beam echosounder (R = 0.67). We measured the distribution of fish school thickness around clusters of large concrete modules of an artificial reef using a multibeam echosounder, complemented with underwater video to aid species identification. The mean distribution of school thickness was mapped around the reef field with generalized additive mixed models. Model spatial predictions indicated schools aggregated around module clusters, rather than individual modules. Dynamic schools of fish in relatively shallow coastal waters (~ 30 m) can be surveyed over 400,000 m2 at 3 m s−1 in just 60 min. Portable multibeam echosounders are an accessible and valuable addition to quantifying the dynamic distributions of coastal fishes around features with high vertical relief.

Аутфітосозологічна характеристика піщаних терас долинного комплексу Дніпро-Карань (Середнє Придніпров’я)

Виконано дослідження стану збереженості раритетної компоненти флори ділянки на лівому березі середньої течії Дніпра площею 19036,5 га, що є об’єктом Смарагдової мережі UA0000337 «Дівички» та пропонується до створення в цих межах національного природного парку. Рослинність представлена лучно-болотними, лісо-чагарниково-болотними та лісовими угрупованнями. У ландшафтно-генетичному відношенні панівними є чотири типи місцевостей: мілководні акваторії давньостаричних озерець та прибережні мілководдя із водною та прибережно-водною рослинністю; підтоплені сегменти притерасних та западинних знижень борової тераси із комплексом чагарниково-лісо-лучно-болотної рослинності; знижених рівнинних та слабопогорбованих сегментів борової тераси із середньобагатими свіжими дерново-підзолистими ґрунтами із суборами та дібровами; сегменти піднять еолового походження із сухими слабосформованими ґрунтами та пісками із сухими борами, сосновими рідколіссями та псамофільними пустошами. Станом на сьогодні, на даному етапі дослідження флори території долинного комплексу піщаних терас Дніпро-Карань можна стверджувати про зростання тут 6 видів-созофітів міжнародного, 13 загальнодержавного та 7 регіонального значення. Із числа охоронюваних видів загальноєвропейського значення виявлені популяції 6 видів: Iris hungarica, Jurinea cyanoides, Ostericum palustre, Salvinia natans, Liparis loeselii, Trapa natans (три останні занесені також до Червоної книги України). Окрім цього, на вказаній території зареєстровано популяції ще 10 видів судинних рослин із Червоної книги України, а саме: Dactylorhiza incarnata, Daphne cneorum, Epipactis helleborine, E. palustris, Lycopodiella inundata, Lilium martagon, Neottia nidus-avis, Platanthera bifolia, Pulsatilla pratensis та Stipa borysthenica. Популяції 14 видів-созофітів представлені багатьма локалітетами із високою чисельністю особин та хорошими показниками репродуктивного процесу; 6 видів мають слабку представленість через незначну кількість самих локалітетів та низьку чисельність особин в популяціях; для популяцій 3 созофітів (Liparis loeselii, Lycopodiella inundata, Dryopteris cristata) існує небезпека зникнення у зв’язку із тим, що виявлені лише поодинокі локалітети із незначною чисельністю особин. Зважаючи на сучасний стан та розташування ландшафтного комплексу даної території є досить ймовірним зростання тут ще цілої низки видів-созофітів, що робить актуальним подальше її дослідження.

A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition

Abstract. Eastern boundary upwelling ecosystems (EBUEs) are among the most productive marine regions in the world's oceans. Understanding the degree of interannual to decadal variability in the Mauritania upwelling system is crucial for the prediction of future changes of primary productivity and carbon sequestration in the Canary Current EBUE as well as in similar environments. A multiyear sediment trap experiment was conducted at the mooring site CBmeso (“Cape Blanc mesotrophic”, ca. 20∘ N, ca. 20∘40′ W) in the highly productive coastal waters off Mauritania. Here, we present results on fluxes of diatoms and the species-specific composition of the assemblage for the time interval between March 1988 and June 2009. The temporal dynamics of diatom populations allows the proposal of three main intervals: (i) early 1988–late 1996, (ii) 1997–1999, and (iii) early 2002–mid 2009. The Atlantic Multidecadal Oscillation (AMO) appears to be an important driver of the long-term dynamics of diatom population. The long-term AMO-driven trend is interrupted by the occurrence of the strong 1997 El Niño–Southern Oscillation (ENSO). The extraordinary shift in the relative abundance of benthic diatoms in May 2002 suggests the strengthening of offshore advective transport within the uppermost layer of filament waters and in the subsurface and in deeper and bottom-near layers. It is hypothesized that the dominance of benthic diatoms was the response of the diatom community to the intensification of the slope and shelf poleward undercurrents. This dominance followed the intensification of the warm phase of AMO and the associated changes of the Atlantic Meridional Overturning Circulation. Transported valves (siliceous remains) from shallow Mauritanian coastal waters into the bathypelagic should be considered for the calculation and model experiments of bathy- and pelagic nutrients budgets (especially Si), the burial of diatoms, and the paleoenvironmental signal preserved in downcore sediments. Additionally, our 1988–2009 data set contributes to the characterization of the impact of low-frequency climate forcings in the northeastern Atlantic and will be especially helpful for establishing the scientific basis for forecasting and modeling future states of the Canary Current EBUE and its decadal changes.

Tritodynamia bengalensis n. sp., a new species of brachyuran crab from West Bengal state, India (Decapoda: Brachyura: Macrophthalmidae).

Tritodynamia bengalensis n. sp. is described on the basis of a male specimen dredged from the shallow coastal waters of West Bengal state, India. The new species is morphologically similar to T. bidentata Yang Tang, 2005 and T. serratipes Anker Ng, 2014, but can be distinguished by the carapace shape, dentition of the pollex, relative length of the dactylus of the third maxilliped, proportions of the propodus of the third pereopod, and structure of the male left gonopod. This is the first record of the genus Tritodynamia from India.

Microphytobenthic primary production on exposed coastal sandy sediments of the Southern Baltic Sea using ex situ sediment cores and oxygen optodes

The shallow coastal water zone of the tide-less southern Baltic Sea is dominated by exposed sandy sediments which are typically inhabited by microphytobenthic communities, but their primary production is poorly studied, and hence four stations between 3.0 and 6.2 m depth were investigated. Sediment cores were carefully taken to keep the natural layering and exposed in a controlled self-constructed incubator. Respiratory oxygen consumption and photosynthetic oxygen production were recorded applying planar oxygen optode sensors. We hypothesized that with increasing water depths the effects of wind- and wave-induced erosion and mixing of the upper sediment layer are dampened and expected higher microphytobenthic biomass and primary production in the incubated cores.Our data partly confirm this hypothesis, as cores sampled at the most exposed stations contained only 50% chlorophyll a m−2 compared to the deeper stations. However, primary production was highly variable, probably due to fluctuating sediment-disturbing conditions before the cores were taken. Due to these physical forces sand grains were highly mobile and rounded, and small epipsamic benthic diatoms dominated, which preferentially occurred in some cracks and crevices as visualized by scanning electron microscopy. The data fill an important gap in reliable production data for sandy sediments of the southern Baltic Sea, and point to the ecological importance and relevant contribution of microphytobenthic communities to the total primary production of this marine ecosystem. Oxygen planar optode sensor spots proved to be a reliable, sensitive and fast detection system for ex situ oxygen exchange measurements in the overlying water of intact sediment cores.

Coastal shallow waters explorer imaging spectrometer for aerial remote sensing of shallow waters in UV-VIS-NIR broadband.

Advancements in technology have widened the limits of hyperspectral imaging of remote sensing in mapping shallow water benthic habitats and bathymetry. This paper provides a novel airborne imaging spectrometer for the field. The device, composed of an off-axis two-mirror telescope and an advanced Dyson spectrometer working in the ultraviolet-visible near-infrared region, has been designed, fabricated, and evaluated. It maintained high optical performance, with a pixel spatial resolution better than 0.5 mrad, spectral resolution of 3.5 nm, field of view of 28°, and a high numerical aperture for high SNR in 330-900 nm. The imaging spectrometer will help to obtain a combination of the spectral and textural characteristics of bottom features in shallow waters. These features could result in the ability to map habitats over large coastal systems.

New Possible Earthquake Precursor and Initial Area for Satellite Monitoring

We propose a new possible earthquake precursor, a coastal water jet originating from shallow water gas seeps and colored by sediments, lifted from increased gas seeps emissions, preceding some earthquakes with offshore epicenters along the Bulgarian Black Sea coast and M ≥ 3. The new possible earthquake precursor is site specific and may be observed in shallow coastal water regions where active faults are accompanied by hydrocarbon gas seeps. We point out to a region where it can be easily detected by direct observation and satellite remote sensing, Zelenka methane seeps (ZMS), near the Bulgarian Black Sea coast. The ZMS activation is related to the tectonic stress and fracturing preceding and accompanying the earthquakes in the Shabla-Kaliakra-Balchik region along the northern part of the Bulgarian Black Sea coast. We also propose an earthquake forecasting experiment, based on the following four hypotheses: 1) The change of the methane emission of shallow horizons is related to crustal strain changes preceding earthquakes in the region; 2) extreme change of the activity of underwater methane seepages appears immediately before nearby earthquakes; 3) shallow water methane seepages activity can be monitored by remote sensing; 4) satellites can register effects from an extreme increase in their emissions. The proposed earthquake forecasting experiment is based on the monitoring of methane seepages activity in the ZMS area by direct observation and remote sensing which may provide indication for preparatory earthquake activity preceding offshore earthquakes in the region.