Summer Sea Temperatures Research Articles

Seasonal Molecular Difference in Fibrillar Collagen Extracts Derived from the Marine Sponge Chondrosia reniformis (Nardo, 1847) and Their Impact on Its Derived Biomaterials.

Chondrosia reniformis (Nardo, 1847) is a marine sponge of high biotechnological interest both for its natural compound content and for its peculiar collagen, which is suitable for the production of innovative biomaterials in the form, for instance, of 2D membranes and hydrogels, exploitable in the fields of tissue engineering and regenerative medicine. In this study, the molecular and chemical-physical properties of fibrillar collagen extracted from specimens collected in different seasons are studied to evaluate the possible impact of sea temperature on them. Collagen fibrils were extracted from sponges harvested by the Sdot Yam coast (Israel) during winter (sea temperature: 17 °C) and during summer (sea temperature: 27 °C). The total AA composition of the two different collagens was evaluated, together with their thermal stability and glycosylation level. The results showed a lower lysyl-hydroxylation level, lower thermal stability, and lower protein glycosylation level in fibrils extracted from 17 °C animals compared to those from 27 °C animals, while no differences were noticed in the GAGs content. Membranes obtained with fibrils deriving from 17 °C samples showed a higher stiffness if compared to the 27 °C ones. The lower mechanical properties shown by 27 °C fibrils are suggestive of some unknown molecular changes in collagen fibrils, perhaps related to the creeping behavior of C. reniformis during summer. Overall, the differences in collagen properties gain relevance as they can guide the intended use of the biomaterial.

Analysis of the Spatial and Temporal Variation of Sea Ice and Connectivity in the NEP of the Arctic in Summer in Hot Years

Climate warming has enabled the Arctic region to achieve seasonal navigation, and sea ice concentration is an important factor affecting the navigation of the Arctic waterways. This article uses the Arctic sea ice concentration data of the three highest temperatures in 2016, 2019, and 2020, combined with the Arctic summer sea level pressure, wind field, temperature, temperature anomaly, ice age, and sea ice movement data to analyze the spatial and temporal variation of sea ice and connectivity in the Northeast Passage (NEP) of the Arctic in Summer in three hot years, and summarizes the causes of sea ice anomalies. The results show that: (1) the summer Arctic sea ice extent in 2016, 2019 and 2020 were all lower than the multi-year average sea ice extent, and the summer sea ice extent in 2020 had the largest change trend; (2) in October of these three years, the sea ice was all negative anomalies, extending the opening time of the NEP; (3) when the sea ice concentration was 30% as the threshold, the navigation period of the NEP in 2016 was from mid-August to late October, 2019 was from the beginning of August to mid-October, 2020 was from the end of July to the end of October, and 2020 was the longest year since the opening of the NEP; (4) when the sea ice concentration was 10% as the threshold, the navigation period of the NEP in 2016 was from the end of August to the end of October, 2019 was from early August to mid-October, and 2020 was from the beginning of August to the end of October; (5) the key navigable areas of the NEP in the past three years were the central waters of the East Siberian Sea, the New Siberian Islands and the Vilkitsky Strait; (6) the navigation period of the NEP in 2016, 2019 and 2020 was longer. The main reasons were that the temperature of the NEP in the past 3 years was relatively high, the wind was weak, the sea ice movement had little effect, and the sea ice age in the key navigable areas was first year ice, which was easy to melt, which greatly promoted the opening of the NEP.

The impact of rising sea temperatures on an Arctic top predator, the narwhal

Arctic top predators are expected to be impacted by increasing temperatures associated with climate change, but the relationship between increasing sea temperatures and population dynamics of Arctic cetaceans remains largely unexplored. Narwhals (Monodon monoceros) are considered to be among the most sensitive of Arctic endemic marine mammals to climate change due to their limited prey selection, strict migratory patterns and high site fidelity. In the context of climate change, we assume that the population dynamics of narwhals are partly influenced by changes in environmental conditions, with warm areas of increasing sea temperatures having lower abundance of narwhals. Using a unique large dataset of 144 satellite tracked narwhals, sea surface temperature (SST) data spanning 25 years (1993–2018) and narwhal abundance estimates from 17 localities, we (1) assessed the thermal exposure of this species, (2) investigated the SST trends at the summer foraging grounds, and (3) assessed the relationship between SST and abundance of narwhals. We showed a sharp SST increase in Northwest, Mideast and Southeast Greenland, whereas no change could be detected in the Canadian Arctic Archipelago (CAA) and in the Greenland Sea. The rising sea temperatures were correlated with the smallest narwhal abundance observed in the Mideast and Southeast Greenland (< 2000 individuals), where the mean summer sea temperatures were the highest (6.3 °C) compared to the cold waters of the CAA (0.7 °C) that were associated with the largest narwhal populations (> 40,000 individuals). These results support the hypothesis that warming ocean waters will restrict the habitat range of the narwhal, further suggesting that narwhals from Mideast and Southeast Greenland may be under pressure to abandon their traditional habitats due to ocean warming, and consequently either migrate further North or locally go extinct.

Features of the Three Dimensional Structure in the Pacific Sub-surface Layer in Summer

The anomaly of the summer sea temperature is analyzed by a spatial-temporal synthetically rotated orthogonal function (REOF) at three different depths (0 m, 40 m, and 120 m) over the area 110°E~100°W and 30°S~60°N. The spatial-temporal distribution shows that the “signal” of annual anomaly is stronger in the sub-surface layer than the surface layer, and it is stronger in the eastern equatorial Pacific than in the western area. The spatial structure of the sea temperature anomaly at different layers is related to both the ocean current and the interaction of ocean and atmosphere. The temporal changing trend of the sub-surface sea temperature in different areas shows that the annual mean sea temperature increases and the annual variability evidently increases from the 1980s, and these keep the same trend with the increasing El Nino phenomenon very well.

Increasing thermal stress for tropical coral reefs: 1871\u20132017

Tropical corals live close to their upper thermal limit making them vulnerable to unusually warm summer sea temperatures. The resulting thermal stress can lead to breakdown of the coral-algal symbiosis, essential for the functioning of reefs, and cause coral bleaching. Mass coral bleaching is a modern phenomenon associated with increases in reef temperatures due to recent global warming. Widespread bleaching has typically occurred during El Niño events. We examine the historical level of stress for 100 coral reef locations with robust bleaching histories. The level of thermal stress (based on a degree heating month index, DHMI) at these locations during the 2015–2016 El Niño was unprecedented over the period 1871–2017 and exceeded that of the strong 1997–1998 El Niño. The DHMI was also 5 times the level of thermal stress associated with the ‘pre-industrial’, 1877–1878, El Niño. Coral reefs have, therefore, already shown their vulnerability to the modest (~0.92 °C) global warming that has occurred to date. Estimates of future levels of thermal stress suggest that even the optimistic 1.5 °C Paris Agreement target is insufficient to prevent more frequent mass bleaching events for the world’s reefs. Effectively, reefs of the future will not be the same as those of the past.

Distribution of Polycystine Radiolarians in Bottom Surface Sediments and Its Relation to Summer Sea Temperature in the High-Latitude North Atlantic

An objective of the study is to get new biogeographic information on the modern polycystine radiolarians from the high-latitude North Atlantic. The quantitative radiolarian dataset was compiled from publications and own micropaleontological counts from samples of the bottom surface sediments of the North Atlantic north of 40°N and Nordic Seas. Standard statistical treatment of micropaleontological data by factor analysis reveals five radiolarian assemblages which have their highest load at the specific temperature range in agreement with the oceanographic setting. An occurrence of radiolarian assemblages reflects extension and interaction of the warm North Atlantic and cold Polar/Arctic waters. Radiolarian distribution exhibits good correlation with the climatically averaged summer sea temperature on depth level of 200 m.

The bivalve Glycymeris pilosa as a multidecadal environmental archive for the Adriatic and Mediterranean Seas

We evaluated the potential of Glycymeris pilosa as an environmental indicator for the Mediterranean region by applying sclerochronological techniques on a sample set collected from Pašman Channel in the middle Adriatic Sea. Maximal longevity of analyzed shells was 69 years. Growth increments in acetate peels of the hinge region had clear boundaries, and there was a strongly synchronous signal in growth-increment width among individuals. The final, replicated chronology spanned 1969 to 2013. Shell growth negatively correlated with local summer sea temperatures and positively with November precipitation. High correlation between shell growth and circulation patterns in the northern Ionian was also observed, with slower growth occurring during cyclonic regimes. Given its broad distribution in the region and the ability to crossdate, generate annually-resolved chronologies, and of a length that substantially overlaps with observational records, G. pilosa has considerable potential to test hypotheses relating to environmental variability and biological response in the Mediterranean.

Trends and Factors Influencing the Length, Compensatory Growth, and Size‐Selective Mortality of Juvenile Bristol Bay, Alaska, Sockeye Salmon at Sea

AbstractThe productivity of Bristol Bay, Alaska, Sockeye Salmon Oncorhynchus nerka increased during the mid‐1970s. This increase is believed to be partially due to an increase in early marine growth associated with the 1976–1977 cool‐to‐warm shift in summer sea surface temperature (SST). The body size of juvenile salmon during their first year at sea is believed to regulate their ability to survive over winter. The back‐calculated smolt length, first‐year ocean growth, and total juvenile length of Sockeye Salmon from five Bristol Bay river systems (Egegik, Kvichak, Naknek, Ugashik, and Wood) and two smolt ages were used to examine trends and factors influencing total juvenile length, compensatory growth, and size‐selective mortality in the first year in the ocean from 1962 to 2007. Juvenile length increased in relation to summer sea temperature, the 1977–2001 and 2002–2007 warm temperature regimes, smolt length, and compensatory growth. Compensatory growth—an inverse relationship between first‐year ocean growth and smolt size—increased over time as well as after the 1976–1977 climate regime shift, was more common in age‐1.0 fish than in age‐2.0 juveniles, and was important in determining the length of juvenile Sockeye Salmon from the Wood River (the shorter fish among rivers and smolt ages). The coefficient of variation in length did not change with SST, suggesting that size‐selective mortality occurred prior to the end of the first year at sea for all 10 fish groups. The predictor variables that were significant in the models varied among river systems and smolt ages. This study demonstrated that the frequency of compensatory growth and the total lengths of juvenile Sockeye Salmon during their first year at sea increased with summer SST (range, 7.5–10.5°C) in the eastern Bering Sea, a possible mechanism for the increased productivity of Bristol Bay Sockeye Salmon associated with warmer sea temperatures.Received June 2, 2015; accepted February 23, 2016

Sea surface temperature and torrential rains in the Valencia region: modelling the role of recharge areas

Abstract. Heavy rain events are frequently recorded in the Western Mediterranean causing economic losses and even human casualties. The Western Mediterranean is a deep and almost closed sea surrounded by high mountain ranges and with little exchange of water with the Atlantic ocean. A main factor in the development of torrential rains is ocean-atmosphere exchanges of heat and moisture that can potentially destabilize air masses travelling over the sea. The study of air mass trajectories previous to the rain event permits the identification of sea areas that could probably contribute to the development or intensification of rainfall. From a previous Mediterranean sea surface temperature climatology, its spatio-temporal distribution patterns have been studied showing two main distribution modes in winter and summer and transitional regimes in spring and autumn. Hence, three heavy precipitation events, for such winter and summer sea temperature regimes and for fall transition, affecting the Valencia region have been selected to study the effect of sea surface temperature in torrential rains. Simulations with perturbed sea surface temperature in different areas along the air mass path were run to compare results with unperturbed simulation. The variation of sea surface temperature in certain areas caused significant changes in model accumulated values and its spatial distribution. Therefore, the existence of areas that at a greater extent favour air-sea interaction leading to the development of torrential rainfall in the Valencia region has been shown. This methodology could be extended to the whole Mediterranean basin to look for such potential recharge areas. The identification of sea areas that contribute to the development or intensification of heavy rain events in the Mediterranean countries could be a useful prognosis and/or monitoring tool.

Patterns of coral settlement in an extreme environment: the southern Persian Gulf (Dubai, United Arab Emirates)

Coral settlement is a key ecological process in the maintenance, recovery and resili- ence of coral reef ecosystems. Coral reefs in the Persian Gulf survive in one of the world's most extreme environments, yet there remains limited knowledge of the role of coral settlement consid- ered critical for maintaining population dynamics. Spatial and temporal patterns of coral settle- ment were examined at 6 sites in Dubai, United Arab Emirates, using settlement tiles deployed and collected every 3 mo from 2009 to 2011 following coral community surveys. Settlement was highly seasonal with the highest settlement rates between June and August (3.2 spat tile �1 ± 0.21 SE), when summer sea temperatures approached 35°C. There was a smaller settlement pulse between September and November, but no settlement between December and May. Settlement was observed 1 to 4 mo after the major spawning season (April and May), suggesting either delayed settlement of larvae, or spatial and/or taxonomic disparity between studies of reproduc- tion versus settlement. Settlement rates varied significantly among sites, but spatial variation was consistent between the 2 years of the study, suggesting strong effects of local environmental con- ditions or local coral assemblages. Poritidae and Acroporidae comprised 27 and 11% of the spat respectively, there were no Pocilloporidae and the most abundant coral spat (61%) were from other, not identifiable, families. These data indicate that observed long-term shifts in the commu- nity structure of adult coral assemblages are being reinforced through a combination of settlement and post-settlement processes, such that there is limited scope for recovery of former Acropora - dominated coral assemblages in the Persian Gulf.

Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon

AbstractFarley, E. V., Starovoytov, A., Naydenko, S., Heintz, R., Trudel, M., Guthrie, C., Eisner, L., Guyon, J. R. 2011. Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon. – ICES Journal of Marine Science, 68: 1138–1146. Overwinter survival of Pacific salmon (Oncorhynchus sp.) is believed to be a function of size and energetic status they gain during their first summer at sea. We test this notion for Bristol Bay sockeye salmon (O. nerka), utilizing data from large-scale fisheries and oceanographic surveys conducted during mid-August to September 2002–2008 and from February to March 2009. The new data presented in this paper demonstrate size-selective mortality for Bristol Bay sockeye salmon between autumn and their first winter at sea. Differences in the seasonal energetic signatures for lipid and protein suggest that these fish are not starving, but instead the larger fish caught during winter apparently are utilizing energy stores to minimize predation. Energetic status of juvenile sockeye salmon was also strongly related to marine survival indices and years with lower energetic status apparently are a function of density-dependent processes associated with high abundance of juvenile sockeye salmon. Based on new information regarding eastern Bering Sea ecosystem productivity under a climate-warming scenario, we hypothesize that sustained increases in spring and summer sea temperatures may negatively affect energetic status of juvenile sockeye salmon, potentially resulting in increased overwinter mortality.

Spatial Distribution, Energetic Status, and Food Habits of Eastern Bering Sea Age‐0 Walleye Pollock

AbstractAge‐0 walleye pollock Theragra chalcogramma were collected from the eastern Bering Sea during years when ocean temperatures were anomalously warm (2004‐2005) and cool (2006‐2007). Variability in spatial distribution, food habits, energetic condition, and recruitment to the age‐1 life stage was investigated in relation to thermal regime. Age‐0 walleye pollock were large in size and widely distributed during warm years, whereas they were small and largely confined to the middle domain of the eastern Bering Sea during cool years. Energy density was positively correlated with body weight and was greater during years when conditions were anomalously cool. The proportion of smaller age‐0 walleye pollock in the diet of larger individuals was high when conditions were warm (21.9% of diet by weight), and euphausiids were the most important prey (36.5% of diet by weight) when conditions were cool. Eastern Bering Sea age‐0 walleye pollock were abundant and broadly distributed from Bristol Bay to offshore and northern locations during warm years; during cool years, age‐0 fish were less abundant and their distribution was constricted to the southeastern Bering Sea. An inverse relationship between brood year abundance and survival from age 0 to age 1 was found. Our results indicate that when spring (summer) sea temperatures on the eastern Bering Sea shelf are very warm and when the water column is highly stratified during summer, age‐0 walleye pollock allocate more energy to growth than to lipid storage, leading to low energy density before winter and thus to higher overwinter mortality.

Status, trends, and patterns of covariation of breeding seabirds at St Lazaria Island, Southeast Alaska, 1994–2006

AbstractAim We examined patterns of covariation among piscivorous and planktivorous seabirds breeding at St Lazaria Island in order to evaluate their responses to interannual changes in sea surface temperature, a variable that affects marine food webs. In addition, we evaluated seabird population trends for responses to decadal‐scale changes in the marine ecosystem.Location St Lazaria Island, Sitka Sound, Alaska.Methods Established seabird monitoring protocols for the Alaska Maritime National Wildlife Refuge were followed in estimating population trends, the timing of nesting events and the reproductive success of eight species of seabirds between 1994 and 2006.Results Population increases were noted for storm‐petrels (Oceanodroma furcata and O. leucorhoa), rhinoceros auklets (Cerorhinca monocerata) and glaucous‐winged gulls (Larus glaucescens). We found no population trend for pelagic cormorants (Phalacrocorax pelagicus), but it appeared that populations of common (Uria aalge) and thick‐billed (U. lomvia) murres and of tufted puffins (Fratercula cirrhata) declined. We detected no linear trends in either breeding chronology or reproductive success over the study period for any seabird. All species of piscivorous seabirds apparently responded similarly to environmental cues as there was a positive covariation among species in the timing of nesting. Piscivores tended to nest earlier, and most species had higher rates of reproductive success in years with relatively warm spring sea temperatures. In contrast, planktivorous Leach’s storm‐petrels (O. leucorhoa) tended to nest earlier when spring and summer sea temperatures were relatively cool. Clearly, seabirds at St Lazaria were responding to interannual changes in sea temperatures near the breeding colony, probably as a result of effects on the food webs.Main conclusions Every seabird species we monitored at St Lazaria exhibited significant population trends between 1994 and 2006. For most species there appeared to be a relationship between both the timing of nesting and reproductive rates and spring or summer sea surface temperatures. Responses at both decadal (populations) and interannual (timing and reproductive success) scales make seabirds useful candidates for helping to monitor change in the marine environment.

Fathers in hot water: rising sea temperatures and a Northeastern Atlantic pipefish baby boom

We report unprecedented numbers of juvenile snake pipefish, Entelurus aequoreus, in continuous plankton records of the Northeastern Atlantic since 2002. Increased sea surface temperatures (SSTs) in the Northern Hemisphere, linked to global warming, are a likely cause. Analysis of a long-term time-series of SST data in the Northeastern Atlantic shows a rise in winter, spring and summer sea temperatures (January-September), when the eggs of E. aqueoreus, which are brooded by the male, are developing and the larvae are growing in plankton. From what is known of the reproductive biology of closely related species, we suggest that the increased abundance of larval and juvenile E. aequoreus in the plankton as far west as the Mid-Atlantic Ridge may reflect the impact of temperature on abundance, through its effects on the operational sex ratio and potential reproductive rate, the onset of the breeding season and juvenile survival in this sex role reversed fish.

Late Pleistocene–Holocene radiolarian paleotemperatures in the Norwegian Sea based on artificial neural networks

Artificial Neural Networks (ANN) were trained by using an extensive radiolarian census dataset from the Nordic (Greenland, Norwegian, and Iceland) Seas. The regressions between observed and predicted Summer Sea Temperature (SST) indicate that lower error margins and better correlation coefficients are obtained for 100 m (SST 100) compared to 10 m (SST 10) water depth, and by using a subset of species instead of all species. The trained ANNs were subsequently applied to radiolarian data from two Norwegian Sea cores, HM 79-4 and MD95-2011, for reconstructions of SSTs through the last 15,000 years. The reconstructed SST is quite high during the Bølling–Allerød, when it reaches values only found later during the warmest phase of the Holocene. The climatic transitions in and out of the Younger Dryas are very rapid and involve a change in SST 100 of 6.2 and 6.8 °C, taking place over 440 and 140 years, respectively. SST 100 remains at a maximum during the early Holocene, and this Radiolarian Holocene Optimum Temperature Interval (RHOTI) predates the commonly recognized middle Holocene Climatic Optimum (HCO). During the 8.2 ka event, SST 100 decreases by ca. 3 °C, and this episode marks the establishment of a cooling trend, roughly spanning the middle Holocene (until ca. 4.2 ka). Successively, since then and through the late Holocene, SST 100 follows instead a statistically significant warming trend. The general patterns of the reconstructed SSTs agree quite well with previously obtained results based on application of Imbrie and Kipp Transfer Functions (IKTF) to the same two cores for SST 0. A statistically significant cyclic component of our SST record (period of 278 years) has been recognized. This is close to the de Vries or Suess cycle, linked to solar variability, and documented in a variety of other high-resolution Holocene records.

Comparisons of the 1995 and 1998 coral bleaching events on the patch reefs of San Salvador Island, Bahamas

Coral patch reefs around San Salvador Island, Bahamas have been monitored with the aid of Earthwatch volunteers three times a year since 1992. During that period two significant mass bleaching events occurred: autumn 1995, and late summer 1998. Elsewhere in 1995, bleaching was caused by higher-than-normal summer sea temperatures; in San Salvador, however, temperatures were normal. In 1998 a prolonged period of higher-than-normal sea temperatures preceded bleaching on San Salvador and worldwide. During the 1995 event, one of the monitored reefs had twice the percentage of coral colonies bleached as the other two. Bleaching was more evenly distributed among the reefs during the 1998 event. In 1995 Agaricia agaricites was significantly more affected than other coral species, with almost 50% of all its colonies showing bleaching. Bleaching was more evenly spread among coral species in 1998, with five species showing bleaching on more than 40% of their colonies. Bleaching began on Millepora as early as August during the 1998 event and progressed to other species through the remainder of the autumn. In 1995 bleaching was not seen until late autumn and appeared to impact all affected species at about the same time. Recovery from the 1995 event was complete: no coral death or damage above normal background levels were seen. In the 1998 event, all Acropora cervicornis on the monitored reefs died and A. palmata was severely damaged. Millepora sp. lost almost half of their live tissue, and Montastraea sp. showed significant tissue damage following this event. Phototransect analysis suggests that more than 20% of total live tissue on affected species died during the 1998 event. A. cervicornis has demonstrated no re-growth from 1998 to 2000 on monitored reefs. Monitoring has suggested significant differences in causes and courses in these two events.

Temperature and Embryonic Development in Relation to Spawning and Field Occurrence of Larvae of Three Antarctic Echinoderms.

The effects of temperature on development and viability were measured at 14 levels between -2{deg}C and +3{deg}C on embryos of two asteroids (Odontaster validus and Odontaster meridionalis) and an echinoid (Sterechinus neumayeri) from Signy Island, Antarctica. Development rates were 2 to 10 times slower than those for temperate or tropical echinoderms, with times to hatching up to 240 h. Development rates for the two asteroids differed by 1.15 x, and rates for both species approximately doubled over the experimental temperature range. In O. validus, embryo viability was independent of temperature, but in O. meridionalis viability declined with increasing temperature. Development rates for S. neumayeri were little affected by temperature above +0.2{deg}C, but declined rapidly at lower temperatures. Conversely, the number of nonviable eggs was low and constant below +1.7{deg}C, but rose rapidly at higher temperatures. A window of optimal temperature, between +0.2{deg}C and +1.7{deg}C, has therefore been proposed for development time and embryo viability in this population of S. neumayeri. Spawning trials and field observations of larvae indicated that the time of gamete release and periods of larval development in S. neumayeri coincided with austral summer sea temperatures in the same window. Embryos of O. meridionalis and O. validus are released in winter, when temperatures are constantly below -1.6{deg}C. Comparison of the different strategies suggests that larval food supply and predation during planktonic phases are not the dominant ecological factors for these species.

Studies on southern Australian abalone (genus Haliotis) XVIII. Ring formation in H. scalaris

The abalone Haliotis scalaris deposits two fine rings a year in the spire, one in about December and the other from May to July, corresponding roughly to summer and winter sea temperature extremes. Additional fine rings, and in particular brown rings, are deposited in response to boring annelids and drilling muricid gastropods. Multiple regression analysis revealed a relationship between the number of rings in the spire and the variables: age of the shell, extent of infestation by annelids, and the number of brown rings. The analysis showed that additional fine rings’ and brown rings are deposited according to the degree of parasitic attack.

First occurrence and new length record for the bigeye thresher shark in the north‐east Atlantic

The first confirmed record for the bigeye thresher shark Alopias superciliosus caught in the far north‐east Atlantic is described here. The specimen was the longest and heaviest recorded to date. Above‐average summer sea temperatures occurred in the catch area in 1995.

WEATHERING EXPERIMENT ON SPILLED CRUDE OILS USING A CIRCULATING WATER CHANNEL

ABSTRACT Crude oil spilled in the sea is mixed with the sea water by the wind and waves resulting in increases in its water content and viscosity as time passes. We have constructed a small, transfer type circulating water channel of an elliptical cuit-track form. Using an attached circulating unit, together with a war tunnel, artificial waves are generated to enable simulation corresponding to the natural circumstances in the sea. The experiment disclosed the following results.Drastic changes in the properties (water content and viscosity) of the oil depend on the power of waves.Contrasting processes are observed between heavy and light crude oils during weathering.Heavy crude oils form a massive water-in-oil emulsion (mousse) with increases in both water content and viscosity.Light crude oils behave differently at summer sea temperatures,