Changes In Seawater Temperature Research Articles

Effects of "Reduced" and "Business-As-Usual" CO2 Emission Scenarios on the Algal Territories of the Damselfish Pomacentrus wardi (Pomacentridae).

Turf algae are a very important component of coral reefs, featuring high growth and turnover rates, whilst covering large areas of substrate. As food for many organisms, turf algae have an important role in the ecosystem. Farming damselfish can modify the species composition and productivity of such algal assemblages, while defending them against intruders. Like all organisms however, turf algae and damselfishes have the potential to be affected by future changes in seawater (SW) temperature and pCO2. In this study, algal assemblages, in the presence and absence of farming Pomacentrus wardi were exposed to two combinations of SW temperature and pCO2 levels projected for the austral spring of 2100 (the B1 “reduced” and the A1FI “business-as-usual” CO2 emission scenarios) at Heron Island (GBR, Australia). These assemblages were dominated by the presence of red algae and non-epiphytic cyanobacteria, i.e. cyanobacteria that grow attached to the substrate rather than on filamentous algae. The endpoint algal composition was mostly controlled by the presence/absence of farming damselfish, despite a large variability found between the algal assemblages of individual fish. Different scenarios appeared to be responsible for a mild, species specific change in community composition, observable in some brown and green algae, but only in the absence of farming fish. Farming fish appeared unaffected by the conditions to which they were exposed. Algal biomass reductions were found under “reduced” CO2 emission, but not “business-as-usual” scenarios. This suggests that action taken to limit CO2 emissions may, if the majority of algae behave similarly across all seasons, reduce the potential for phase shifts that lead to algal dominated communities. At the same time the availability of food resources to damselfish and other herbivores would be smaller under “reduced” emission scenarios.

Multiple environmental changes induce interactive effects on bacterial degradation activity in the Arctic Ocean

AbstractThe Arctic Ocean faces multiple environmental changes induced by climate change on both global and regional scale. In addition to global changes in seawater temperature and pH, Arctic waters receive organic matter enrichment due to increasing pelagic primary production, enhanced sea ice melting and increasing terrestrial carbon loads. We experimentally tested individual and combined effects of warming, acidification and organic matter amendment on growth, biomass production and extracellular enzyme activities of bacterioplankton in Fram Strait during early summer. Results reveal pH optima of 6.7–7.6 for extracellular leucine‐aminopeptidase and below pH 6.0 for beta‐glucosidase in the West Spitsbergen Current. These optima well below the current seawater pH imply increasing hydrolytic activity with ongoing ocean acidification. However, the new synthesis of extracellular enzymes during 4‐d incubations obscured the biochemical pH effects. Elevated temperature and carbohydrate supply had strongly interactive effects on bacterial biomass production in both Atlantic Water of the West Spitsbergen Current and Polar Water of the East Greenland Current. Activation energies ranged from 45 kJ mol−1 to 52 kJ mol−1 at in situ substrate concentration, while substantially higher values of 122–174 kJ mol−1 could be estimated from incubations with carbohydrate addition. The net loss of total amino acids in carbohydrate‐amended incubations was significantly reduced at elevated temperature in all experiments, suggesting enhanced de novo synthesis. Our findings show that the complexity of combined effects must be considered to better assess the potential of climate change to alter biogenic carbon and energy fluxes in marine systems.

Environmental influence on commercial fishery landings of small pelagic fish in Portugal

Small pelagic fishes are particularly abundant in areas with high environmental variability (zones of coastal upwelling and areas of tidal mixing and river discharge), and because of this, their abundance suffers large inter-annual and inter-decadal fluctuations. In Portugal, the most important species in terms of landings are European sardine, Atlantic horse mackerel and Atlantic chub mackerel. Small pelagic fish landings account for 62.8 % of the total fish biomass and represent 32.7 % of the economical value of all catches. We have investigated trends in landings of these small pelagic fishes and detected the effects of environmental factors in this fishery. In order to explain the variability of landings of small pelagic fishes, we have used official landings (1965–2012) for trawling and purse seine fisheries and applied generalized linear models, using the North Atlantic Oscillation index (NAO) (annual and winter NAO index), sea surface temperature (SST), wind data (strength and North–South and East–West wind components) and rainfall, as explanatory variables. Regression analysis was used to describe the relationship between landings and SST. The models explained between 50.16 and 51.07 % of the variability of the LPUE, with the most important factors being winter NAO index, SST and wind strength. The LPUE of European sardine and Atlantic horse mackerel was negatively correlated with SST, and LPUE of Atlantic chub mackerel was positively correlated with SST. The use of landings of three important species of small pelagic fishes allowed the detection of variations in landings associated with changes in sea water temperature and NAO index.

The effects of water acidification, temperature and salinity on the regenerative capacity of the polychaete Diopatra neapolitana

Changes in seawater pH, temperature and salinity are expected to occur in the near future, which can be a threat to aquatic systems, mainly for marine coastal areas, and their inhabiting species. Hence, the present study proposes to evaluate the effects of temperature shifts, pH decrease and salinity changes in the tissue's regenerative capacity of the polychaete Diopatra neapolitana. This study evidenced that D. neapolitana individuals exposed to lower pH exhibited a significantly lower capacity to regenerate their body, while with the increase of temperature individuals showed a higher capacity to regenerate their tissues. Furthermore, the present work demonstrated that individuals exposed to salinities 28 and 35 did not present significant differences between them, while salinities 21 and 42 negatively influenced the regenerative capacity of D. neapolitana. At the end of regeneration, comparing all conditions, high salinity (42) seemed to have a greater impact on the regenerative capacity of individuals than the other factors, since under this condition individuals took longer to completely regenerate. Overall, this study demonstrated that variations in abiotic factors can strongly affect D. neapolitana's performance.

Century-scale trends and seasonality in pH and temperature for shallow zones of the Bering Sea

No records exist to evaluate long-term pH dynamics in high-latitude oceans, which have the greatest probability of rapid acidification from anthropogenic CO2 emissions. We reconstructed both seasonal variability and anthropogenic change in seawater pH and temperature by using laser ablation high-resolution 2D images of stable boron isotopes (δ(11)B) on a long-lived coralline alga that grew continuously through the 20th century. Analyses focused on four multiannual growth segments. We show a long-term decline of 0.08 ± 0.01 pH units between the end of the 19th and 20th century, which is consistent with atmospheric CO2 records. Additionally, a strong seasonal cycle (∼ 0.22 pH units) is observed and interpreted as episodic annual pH increases caused by the consumption of CO2 during strong algal (kelp) growth in spring and summer. The rate of acidification intensifies from -0.006 ± 0.007 pH units per decade (between 1920s and 1960s) to -0.019 ± 0.009 pH units per decade (between 1960s and 1990s), and the episodic pH increases show a continuous shift to earlier times of the year throughout the centennial record. This is indicative of ecosystem shifts in shallow water algal productivity in this high-latitude habitat resulting from warming and acidification.

Climate change and marine benthos: a review of existing research and future directions in the North Atlantic

There is growing evidence that climate change could affect marine benthic systems. This review provides information of climate change‐related impacts on the marine benthos in the North Atlantic. We cover a number of related research aspects, mainly in connection to two key issues. First, is the relationship between different physical aspects of climate change and the marine benthos. This section covers: (a) the responses to changes in seawater temperature (biogeographic shifts and phenology); (b) altered Hydrodynamics; (c) ocean acidification (OA); and (d) sea‐level rise‐coastal squeeze. The second major issue addressed is the possible integrated impact of climate change on the benthos. This work is based on relationships between proxies for climate variability, notably the North Atlantic Oscillation (NAO) index, and the long‐term marine benthos. The final section of our review provides a series of conclusions and future directions to support climate change research on marine benthic systems. WIREs Clim Change 2015, 6:203–223. doi: 10.1002/wcc.330This article is categorized under: Climate, Ecology, and Conservation > Modeling Species and Community Interactions

Calving of a tidewater glacier driven by melting at the waterline

AbstractWe present a study of the development of a thermo-erosional notch at the waterline and its influence on calving of Hansbreen, a medium-sized grounded tidewater glacier in southern Svalbard. The study is based on the results of undercut notch melt modelling, based on measurements of sea-water properties, repeated terrestrial laser scans and analysis of time-lapse camera images. There is a strong correlation between observed calving activity and modelled melt rate of the undercut notch. Measured depths of the undercut reach 4 m and vary greatly over time. The calving activity of Hansbreen was significantly lower in 2011 than in 2012, due to the persistent presence of the ice pack in Hornsund fjord, which cooled the sea surface and suppressed the wave action. Calving on Hansbreen is controlled by a local imbalance of forces at the front, due to thermo-erosional undercutting at the sea waterline. Calving activity is therefore sensitive to changes in sea-water temperature and wave height. It may be expected that calving rates will rise with increased advection of warm oceanic water to the Arctic.

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

One of the most expanded records to contain the final fortunes of ammonoid cephalopods is within the López de Bertodano Formation of Seymour Island, James Ross Basin, Antarctica. Located at ~65° South now, and during the Cretaceous, this sequence is the highest southern latitude onshore outcrop containing the Cretaceous-Paleogene (K–Pg) transition. We present comprehensive new biostratigraphic range data for 14 ammonite and one nautiloid species based on the collection of >700 macrofossils from high-resolution sampling of parallel sedimentary sections, dated Maastrichtian to earliest Danian in age, across southern Seymour Island. We find evidence for only a single, abrupt pulse of cephalopod extinction at the end of the Cretaceous when the final seven ammonite species disappeared, consistent with most evidence globally. In the lead up to the K–Pg extinction in the James Ross Basin, starting during the Campanian, ammonite diversity decreased overall, but the number of endemic taxa belonging to the family Kossmaticeratidae actually increased. This pattern continued into the Maastrichtian and may be facies controlled, linked to changes in sea level and seawater temperature. During the early Maastrichtian, ammonite diversity dropped significantly with only two species recorded from the basal López de Bertodano Formation on Seymour Island. The subsequent diversification of endemic taxa and reappearance of long-ranging, widespread species into the basin resulted in an increase in ammonite diversity and abundance during the mid-Maastrichtian. This was coincident with an apparent period of warming temperatures and sea level rise interpreted from palynology and sedimentology, perhaps reflecting a high latitude expression of the Mid-Maastrichtian Event. Late Maastrichtian diversity levels remained stable despite reported climatic and environmental variation. Ammonite diversity patterns during the Maastrichtian parallel those of microfossil species such as nannofossil and planktonic foraminifera, suggesting that dynamic climatic and environmental changes affected many planktonic and nektonic organisms during the latest Cretaceous. However, we suggest that these perturbations had a minimal effect on overall diversity prior to the catastrophic extinction event at the K–Pg boundary.

ВИЗНАЧЕННЯ ПАРАМЕТРІВ ТЕПЛООБМІННИХ АПАРАТІВ СИСТЕМИ РЕГАЗИФІ-КАЦІЇ LNG-ТЕРМІНАЛУ ПРОДУКТИВНІСТЮ 5 МЛРД. М3 НА РІК

The paper is devoted to the important scientific and technical problem of development of the modern and high-efficient storage and regasification liquefied natural gas terminal. The design, calculated performance and mass-dimensional parameters of heat exchangers and pumping equipment for the regasification system of the LNG terminal with annual capacity of 5 billion m 3 at the northern Black Sea coast conditions are presented. The regasification system provides evaporation and superheating of liquefied natural gas to meet the given parameters of evaporated gas at the inlet of the main pipeline. The composition of the system includes heat exchangers: reboilers to evaporate the liquefied gas and superheaters to get the necessary temperature of evaporated gas. The seawater is suggested as the source of heat for evaporation and superheating of the natural gas, with the pumping station is to be used for pumping the water through heat exchangers. To make a sufficient investigation the change in seawater temperature throughout the season is had to be taken into account. Peculiarities of the annual maintenance of reboilers, superheaters and pumps due to change in the seawater temperature have been shown in the paper. A shell-and-tube heat exchanger type with multiple reverse flow of LNG is suggested to use for the reboiler. The superheater is designed as the finned-tube heat exchanger with multiple cross-flow of seawater. The set of limits was applied to the calculations among them are: the temperature drop of seawater on the heat exchanger is less then 3 °C (±1) and the maximum permissible speed of seawater in heat exchanger is 2 m/s. According to the calculations, the necessary amount of reboilers and superheaters is 10 items each type with the dimensions of reboiler about 1,25×1,4×4,1 m and superheater about 3,6×1,55×1,55 m. Seawater flow adjustment during the year, corresponding to its temperature, permits to meat ecological limits and to provide the regasification of the daily capacity of liquefied natural gas at the pressure of 4 MPa and outlet temperature greater than 2 oC as it is shown by dint of mathematical simulation. The range of seawater flow is 6700…9350 kg/s, the necessary pumping station power – 4300 kWt

Prediction of paralytic shellfish toxin based on a projected future climate scenario for South Korea

This study aimed to predict the seasonal patterns of paralytic shellfish poison (PSP) level in the next 90years based on a future climate scenario, Representative Concentration Pathway (RCP) 8.5. To achieve this goal, we constructed a censored regression model using seawater temperature, weekly change in seawater temperature, salinity, rainfall, insolation, shell species, and areas prone to red tide as potentially influential environmental factors on PSP level in the coastal areas of South Korea. The censored regression model is used instead of the ordinary regression model because the PSP data had a large portion of non-detectable (ND) data. All of the continuous environmental covariates had significant quadratic relationships with the PSP toxin level except insolation. These results indicated that there are favorable ranges of seawater temperature, weekly change in seawater temperature, salinity, and rainfall to PSP production. To predict the future PSP distribution, we plugged the environmental condition data under a future climate scenario, RCP 8.5 scenario, in the estimated regression model. In the future, it is expected that the highest frequency of shellfish poisoning outbreaks will occur during the earlier months in the year, such as February and March, whereas most outbreaks of shellfish poisoning have occurred in April and May during recent years in South Korea.

Glacial induced closure of the Panamanian Gateway during Marine Isotope Stages (MIS) 95–100 ([formula omitted

The final phase of the closure of the Panamanian Gateway and the intensification of Northern Hemisphere Glaciation (NHG) both occurred during the Late Pliocene. Glacial–interglacial (G–IG) variations in sea level might, therefore, have had a significant impact on the remaining connections between the East Pacific and the Caribbean. Here, we present combined foraminiferal Mg/Ca and δ18O measurements from Ocean Drilling Program (ODP) Site 1241 from the East Pacific and ODP Site 999 from the Caribbean. The studied time interval covers the first three major G–IG Marine Isotope Stages (MIS 95–100, ∼2.5 Ma) after the intensification of NHG. Analyses were performed on the planktonic foraminifera Neogloboquadrina dutertrei and Globigerinoides sacculifer, representing water mass properties in the thermocline and the mixed-layer, respectively. Changes in sea water temperature, relative salinity, and water column stratification strongly suggest that the Panamanian Gateway temporarily closed during glacial MIS 98 and 100, as a result of changes in ice volume equivalent to a drop in sea level of 60–90 m. Reconstructed sea surface temperatures (SST) from G. sacculifer show a glacial decrease of 2.5 °C at Site 1241, but increases of up to 3 °C at Site 999 during glacial MIS 98 and 100 suggesting that the Panamanian Gateway closed during these glacial periods. The Mg/Ca-temperatures of N. dutertrei remain relatively stable in the East Pacific, but do show a 3 °C warming in the Caribbean at the onset of these glacial periods suggesting that the closing of the gateway also changed the water column stratification. We infer that the glacial closure of the gateway allowed the Western Atlantic Warm Pool to extend into the southern Caribbean, increasing SST (G. sacculifer) and deepening the thermocline (N. dutertrei). Additionally, ice volume appears to have become large enough during MIS 100 to survive the relatively short lasting interglacial MIS 99 so that the gateway remained closed. Towards the end of MIS 98, during MIS 97 and into MIS 96 temperatures on both sides are mostly similar suggesting water masses exchanged again. Additionally, Caribbean variations in SST and δ18Owater follow a precession-like cyclicity rather than the obliquity-controlled variations characteristic of the East Pacific and many other tropical areas, suggesting that regional atmospheric processes related to the trade winds and the InterTropical Convergence Zone (ITCZ) had a dominant impact in the Caribbean.

Fisheries in a warming ocean: trends in fish catches in the large marine ecosystems of the world

Trends in annual catches of fish species in the large marine ecosystems (LMEs) of the world were analysed, relating them with changes in sea surface temperature. LMEs are large coastal areas with broad ecosystem similarities, and the vast majority of them have warmed in the period of 1982–2006. Changes in sea water temperature, induced by climate change, affect the geographic distribution of fish species in marine ecosystems. Shifts in distribution of fish will most likely affect the abundance, distribution and composition of fisheries catches. In the present paper, a decreasing trend in the catches of fish species in warming LMEs was observed. Catches in years of cold and warm winters were compared for each of the eight fish species most caught in the world. Generally, mean catches of polar and temperate species were higher in years of warm winters in the LMEs located in the northern part of the species range and in years of cold winters in LMEs of the southern regions of their ranges. Mean catches of subtropical species were higher in cold years in LMEs of lower latitudes and in warm years in LMEs of higher latitude regions. The results obtained for fish catches agree with a poleward shift of fish species as a response to ocean warming, posing challenges for future fisheries management.

Projecting future distribution of the seagrass Zostera noltii under global warming and sea level rise

In future decades, coastal ecosystems are expected to be exposed to increased risk of experiencing adverse consequences related to climate change, exacerbated by human induced pressures. The seagrass Zostera noltii forms meadows mainly within the intertidal zone, leading it to be particularly vulnerable to seawater temperature increase and sea level rise (SLR). Considering the presently declining situation and the predicted scenarios of increasing seawater temperature and SLR by the end of the 21st century, we assessed the response of Z. noltii to climate change (i) accounting for changes in seawater temperature at its entire biogeographical range level; and (ii) under SLR scenarios at estuary level (Oka estuary, Basque Country, south-eastern Bay of Biscay). Objectives were addressed coupling habitat suitability models with climate change simulations. By the end of the 21st century, seawater temperature increase will trigger a northward distributional shift of 888km in the suitable habitat of the species, and a retreat of southernmost populations. The loss of southernmost populations due to climate change may imply future conservation problems. In contrast, SLR and derived changes in current velocities are expected to induce the landward migration of the species in the Oka estuary, increasing the available suitable intertidal areas (14–18%) to limits imposed by anthropogenic barriers. This modelling approach could lead to an advanced understanding of the species’ response to climate change effects; moreover, the information generated might support conservation actions towards the sites where the habitat would remain suitable for the species under climate change.

Carbon isotope evidence for sedimentary discontinuities in the lower Toarcian of the Lusitanian Basin (Portugal): Sea level change at the onset of the Oceanic Anoxic Event

The Toarcian Oceanic Anoxic Event (T-OAE), Early Jurassic, was an episode of rapid warming and deep perturbation of the carbon cycle, as suggested by the large carbon and oxygen isotope excursions recorded by various carbonate and organic materials of this age. Previous studies have shown that strata deposited immediately below the T-OAE are marked by widespread discontinuities, but their duration and synchronicity remain uncertain. In this study, we use the carbon isotope profiles of twelve sections from the Lusitanian Basin, Portugal, to correlate shallower and deeper settings and identify the durations and possible causes of these discontinuities. The obtained correlation suggests the existence of three major discontinuities. The first occurs close to the Pliensbachian–Toarcian boundary and locally corresponds to an interval of condensation due to rapid transgression. The second and most marked discontinuity occurs in the mid-upper part of the Polymorphum ammonite Zone. Depending on the location in the Lusitanian Basin, this discontinuity is interpreted to reflect either marine erosion (in deeper parts of the basin) or subaerial exposure (in the shallow parts of the basin), both induced by a high-amplitude sea-level fall. In intermediate parts of the basin, this discontinuity is interpreted as a transgressive ravinement surface due to subsequent sea-level rise. This latter transgression induced the formation of a third discontinuity of sedimentary condensation (uppermost Polymorphum Zone) that corresponds to the interval of highest rate of sea-level rise just before the onset of the T-OAE. The comparison of the carbon isotope record of the Lusitanian Basin with that of other European basins indicates that these discontinuities are present on a wide paleogeographical scale within the western Tethys, and correspond to marked changes in seawater temperatures and CO2 levels, implying a control by high-amplitude, likely glacio-eustatic sea-level changes.

Seawater temperature changes associated with the North Brazil current dynamics

This study used hydrographic data (CTD and ADCP) collected along the north Brazilian continental shelf and the adjacent oceanic area (the north Brazilian zone) and 13 years of monthly data of sea surface temperatures (SSTs) obtained from the Tropical Rainfall Measuring Mission satellite microwave images. In July and August 2001, the core of the North Brazil Current (NBC) with a velocity exceeding 1.2 m s−1 in the upper 150 m was observed near the break of the north Brazilian continental shelf. The satellite and in situ SSTs from the same time indicate that relatively cold waters (<27.5 °C) extended throughout the NBC region where the vertical distribution of temperature displayed a rise of the 26 °C isotherm to near the surface on transects where the NBC was more intense. These observations indicated that the NBC plays an important role in temperature changes in the water column near and/or over the north Brazilian continental shelf margin even at times when, theoretically, the NBC may be expected to be less intense (April–May) and warm waters dominate the area. The distribution of accumulated temperature change reveals that the NBC may contribute to possible nutrient upwelling of the bottom boundary layer along the continental shelf to surficial areas and offshore following the NBC deflection or merely into the North Atlantic.

Upper Campanian–Maastrichtian holostratigraphy of the eastern Danish Basin

One of the most expanded upper Campanian–Maastrichtian successions worldwide has been cored in a series of boreholes in eastern Denmark. A high-resolution holostratigraphic analysis of this part of the Chalk Group has been undertaken on these cores, notably Stevns-1, in order to provide a record of changes in chalk facies, water depths and sea-water temperatures. Combined lithological data, a suite of petrophysical logs including gamma ray (GR) logs, nannofossil and dinoflagellate palaeontology, stable carbon isotopes, seismic reflection and refraction sections form the basis for the definition of two new formations and six members, three of which are new, and for recognition of Boreal nannofossil subzones UC15eBP to UC20dBP. The upper Campanian–lowermost Maastrichtian Mandehoved Formation is subdivided into the Flagbanke and Boesdal Members and the Maastrichtian Møns Klint Formation is subdivided into the Hvidskud, Rørdal, Sigerslev, Kjølby Gaard Marl and Højerup Members. The Boesdal and Rørdal Members show high GR values and a pronounced chalk-marl cyclicity. The Rørdal and the thin Kjølby Gaard Marl Members have a regional distribution and can be traced over most of the Danish Basin, whereas the Højerup Member is restricted to the easternmost part of Sjælland. The other members consist of rather featureless white chalk.

Range expansions across ecoregions: interactions of climate change, physiology and genetic diversity

AbstractAimClimate change is expected to drive range shifts among a wide array of organisms. Non‐indigenous species (NIS) provide a unique opportunity to observe the establishment of range boundaries in a way that cannot be directly seen for native species. Recent studies have indicated that climate change facilitates biological invasions at local scales. However, the generality of these effects is unclear, as there is a dearth of comparative studies that assess how rapid environmental change affects species ranges across taxa and biogeographic provinces.LocationThe South African coast and other coastlines across the world.MethodsWe first studied the distribution of shallow‐marine benthic organisms along the South African coastline and analysed the global distribution of NIS. We then obtained DNA sequence data from a suite of co‐occurring NIS from along the studied coastline and compared these data with available genetic information from other regions of the world. Subsequently, we conducted physiological experiments to assess how thermal tolerance was related to species distribution. Finally, we analysed ship‐based seawater temperature records and compared these with past changes in the range size and abundance of NIS. These records were used to estimate shipping intensity and NIS propagule pressure.ResultsWe found that NIS with a variety of thermal tolerances and distributions have expanded their ranges and increased in abundance as seawater temperature regimes have changed. We found little interannual variation in shipping transport intensity. Most haplotypes of the studied NIS in South Africa were shared with other regions.Main conclusionsThis study provides empirical evidence that NIS, regardless of their thermal tolerance, range size and genetic variability, are expanding their ranges and increasing in abundance. This trend is uncorrelated with levels of human‐mediated NIS transport but concurrent with changes in seawater temperature, which suggests that climate change fosters the spread and abundance of NIS across multiple spatial scales.

Impact of temperature and prey shell thickness on feeding of the oyster drill Urosalpinx cinerea Say

Feeding rates and selection of the oyster drill Urosalpinx cinerea were investigated with several long term temperature alteration experiments. Oyster drill prey selection was assessed in terms of prey (oyster) size and shell thickness. Drills fed on oysters with thinner shells 86% of the time and selectively preyed on smaller (1g wet weight) oysters during colder months and larger (10g wet weight) oysters during warmer months. Analysis of U. cinerea seasonal feeding patterns showed virtually no feeding during winter months (January to March) and a significant increase to over 1 gram of prey tissue per week during summer (July to September). A nine month experiment compared feeding rates of U. cinerea at two different temperature levels: ambient seawater (control) and temperatures elevated 4°C above ambient. Oyster drills showed a 60% increase in feeding rate in the warmer treatment, especially during late summer, fall and early winter. Both temperature manipulation and annual feeding experiments revealed a significant temperature dependence of U. cinerea feeding rates. Seasonal or long-term seawater temperature changes related to climate change could strongly affect the predator–prey relationship between U. cinerea and its prey.

Mass transport‐dominated sedimentation in a foreland basin, the Hidaka Trough, northern Japan

Mass transport is an important process of sediment redistribution from shallow to deep sea basins. It is vital to understand this process for disaster prevention and protection of economic interests in coastal and offshore areas. We describe mass transport‐dominated sedimentation in an active foreland basin, the Hidaka Trough, which developed from collision between the northeastern Japan arc and the Kuril arc. The basin is deformed by east‐west compression associated with large, frequent earthquakes. The trough is filled with thick (&gt;4.5 km) sediments, ranging from coal‐bearing Cretaceous terrestrial strata to modern diatomaceous hemipelagic mud and volcanic ash. Bottom‐simulating reflectors and the distribution of mud volcanoes, pockmarks, and acoustic wipe‐out zones on the seismic records suggest the presence of subsurface gases in the sediments. The basin features stacked mass transport deposits (MTDs), but no channel‐levee systems have developed. The MTDs are relatively thin (&lt;30 m) and are derived from three sides of the basin margin. Initiation of submarine slope failure in this area may be controlled by multiple factors that increase driving forces and decrease resistance of the slopes. The driving forces include oversteepening of the margin slope as a result of thrusting and folding, and additional downslope gravitational acceleration caused by cyclic shaking during earthquakes. Decreased resistance in the slopes may be caused by the accumulation of excess pore‐water pressure driven by a high‐sedimentation rate, gas hydrate dissociation accompanying changes in sea level or seawater temperature, and liquefaction in coarse‐grained beds during earthquakes.

Faunal shift in southern California's coastal fishes: A new assemblage and trophic structure takes hold

Trends in coastal fish abundance indices were examined using a novel 39-year (1972–2010) time series recorded at southern California coastal power plants. Since 1972, the annual mean abundance index significantly declined (r2 = 0.45, p < 0.001). The mean annual biomass index likewise declined but with a large interruption in 2005–2006 when an influx of large bodied, southern species increased the annual means. Ensemble mean abundance indices for fished and unfished species declined at similar rates. Two faunal shifts were identified, 1983–1984 and 1989–1990. The ensemble mean, annual entrapment rate abundance index during the current period (1990–2010) represents only 22% of that recorded during the first and most abundant period, 1972–1983. The mean biogeographic distribution of the assemblage was non-linear over time including a shift south during the 1980s through the 1990s before shifting north in recent years. The northern shift in recent years accompanied higher variability than previously recorded and was likely related to the overall low abundance. Since the early 1980s, the mean trophic level derived from abundance declined. The observed patterns were not correlated with commonly employed composite indices such as the Pacific Decadal Oscillation, but did show some sensitivity to changes in coastal seawater temperature and density over time. Timing of the observed faunal shifts in the fish assemblage was consistent with reported oceanographic shifts. These data suggested factors beyond fishing, such as oceanographic change, have substantially impacted the coastal fishes of southern California.