Oceanography

Environmental conditions can influence the physiology of marine organisms and have important implications for their reproductive performance and capacity to supply new recruits. This study examined the seasonal reproductive patterns of the coral Montipora capitata in habitats exposed to different sedimentation regimes. Although M. capitata is a main reef-building coral in the Hawaiian Archipelago, little is known about the gametogenic cycle and reproductive ecology of this important species. Our results indicate that gamete production in M. capitata is a resilient process; no differences in gamete development or fecundity were observed among sites with very different sedimentation regimes. The gametogenic cycle of M. capitata lasts between 10 and 11 months, with spawning occurring over 3-5 months during warmer months (May-September). Oocytes were found throughout the year, but spermatocysts were only found April-August. The largest increases in oocyte size occurred during February to May, the months when solar radiation increased rapidly. The largest variation in oocyte sizes was found during July and August; during this period individual colonies contained mature oocytes for immediate spawning and new oocytes being formed for spawning the next year. The capacity of M. capitata to reproduce in areas with high sedimentation is an interesting finding highlighting the potential of the species for acclimatization, adaptation, or both. Despite this optimistic finding, the management of terrestrial runoff and the restoration of habitat quality for corals remains a top priority to ensure the renewal and maintenance of coral populations.

Multiple tracers of groundwater input (salinity, Si, 223 Ra, 224 Ra, and 226 Ra) were used together to determine the magnitude, character (meteoric versus seawater), and nutrient contribution associated with submarine groundwater discharge across the leeward shores of the Hawai'ian Islands Maui, Moloka'i, and Hawai'i. Tracer abundances were elevated in the unconfined coastal aquifer and the nearshore zone, decreasing to low levels offshore, indicative of groundwater discharge (near-fresh, brackish, or saline) at all locations. At several sites, we detected evidence of fresh and saline SGD occurring simultaneously. Conservative estimates of SGD fluxes ranged widely, from 0.02-0.65 m 3 m − 2 d − 1 at the various sites. Groundwater nutrient fluxes of 0.04-40 mmol N m − 2 d − 1 and 0.01-1.6 mmol P m − 2 d − 1 represent a major source of new nutrients to coastal ecosystems along these coasts. Nutrient additions were typically greatest at locations with a substantial meteoric component in groundwater, but the recirculation of seawater through the aquifer may provide a means of transferring terrestrially-derived nutrients to the coastal zone at several sites.

Global mean sea levels are projected to gradually rise in response to greenhouse warming. However, on shorter time scales, modes of natural climate variability in the Pacific, such as the El Niño–Southern Oscillation (ENSO), can affect regional sea level variability and extremes, with considerable impacts on coastal ecosystems and island nations. How these shorter-term sea level fluctuations will change in association with a projected increase in extreme El Niño and its atmospheric variability remains unknown. Using present-generation coupled climate models forced with increasing greenhouse gas concentrations and subtracting the effect of global mean sea level rise, we find that climate change will enhance El Niño–related sea level extremes, especially in the tropical southwestern Pacific, where very low sea level events, locally known as Taimasa, are projected to double in occurrence. Additionally, and throughout the tropical Pacific, prolonged interannual sea level in-undations are also found to become more likely with greenhouse warming and increased frequency of extreme La Niña events, thus exacerbating the coastal impacts of the projected global mean sea level rise.

1 Abstract 2 Introduction 2 Background 5 Drill sites 7 Scientific objectives 9 Operational strategy 12 Summary of achievements 12 Principal expedition results 26 Preliminary scientific assessment 27 Offshore operations 29 Outreach and communication 29 References

Straight-ahead resistance tests and static-yaw runs up to 20°yaw angle for the axi-symmetric bare hull configurations of the ''Phoenix'' underwater vehicle that were performed in the 90 m towing tank at the Institute for Ocean Technology, National Research Council, Canada, provided empirical formulae for the drag force, lift force and turning moment that are exerted on such axi-symmetric torpedo-shaped hull forms. The empirical formulae were then embedded in a numerical code to simulate the constant-depth planar manoeuvres of the MUN Explorer autonomous underwater vehicle (AUV). The simulation model was first calibrated using the sea-trial data, and then was used to study the turning manoeuvres and to compare the simulation results with those from theoretical formulae based on the linearized equations of motion. The simulation results show non-linear changes in the hydrodynamic coefficients as the turning manoeuvre becomes tighter.

To enable a relevant interpretation of otolith strontium : calcium (Sr/Ca) variations in terms of habitat shifts of eels, the Sr/Ca-salinity relationship in eel otoliths was validated. Downstream and upstream migrations of young eels were reproduced in the laboratory by transferring groups of fish every 2 months between aquaria filled with water coming from the Dordogne river (salinity = 0), the upper Gironde estuary (salinity = 5), the lower Gironde estuary (salinity = 25) and the coast (salinity = 30), which represented the salinity gradient observed in the Gironde-Garonne-Dordogne watershed. Ontogenetic changes in otolith Sr/Ca were assessed in two groups of control fish that were kept in one of either two constant salinities (fresh water or seawater). X-ray electron microprobe (wavelength dispersive spectrometry, WDS) analyses of Sr/Ca ratios in the otoliths showed that the change of aquarium was recorded as a Sr/Ca increase (downstream migration) or a Sr/Ca decrease (upstream migration). No ontogenetic effect was detected in otoliths of control fish outside glass eel marks in either group of fish. The electron microprobe (WDS) analysis of the Sr/Ca life (transected in several otoliths of eels caught in the Gironde-Garonne-Dordogne watershed) showed that some of them were migrant eels that had experienced one major habitat shift during their continental life.

A cohort model for the European eel is presented, which enables the interpretation of observed catches of yellow eel and silver eel in the western Wadden Sea in terms of recruitment data of glasseel. The model builds on various assumptions on length-dependent mortality and silvering rates and on the standard Dynamic Energy Budget (DEB) model which predicts length growth. DEB parameter values are estimated on the basis of literature data. The model predictions are generally in good agreement with the data, though the final decline in numbers in the 1980s occurs earlier than predicted. This suggests that the decrease in eel stock is not just a consequence of lower glasseel immigration but that local conditions must have impoverished, a phenomenon earlier observed in fresh water.

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher Permissions may be sought directly from Elsevier's Science & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: [email protected]. Alternatively you can submit your request online by visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material.

The hydrography and circulation of Conception Bay (Newfoundland) are described based on hydrographie, current-meter and drifter data collected over four years (1988)(1989)(1990)(1991). The seasonal cycles of température (-1.6 to 13-17°C) and salinity (31-32.5) in thé boy closely follow those on thé adjacent shelf. Exchange of bottom water was observed in April 1989. Deepwater exchange was observed from late fait to early winter of 1989-90. Tidal currents are weak, 1-2 cm s~' for thé MI and K\ consiituents. Observed Eulerian mean currents (<.3 cm s~* ) are smaller than thé standard déviation (1-11 cm s~ ); however, there is a persistent outflowing current of 10 to 20 cm s~ within 2 km of thé shoreline on thé eastern side of thé outer bay. The Lagrangian corrélation length scale is from 4 to 10 km, in agreement with thé weak cohérence squared (^0.4) found between thé fixed current-meter sites separated by greater than 4-5 km. The variable currents (up to 20 cm s~] ) tend to be cyclonic. Cyclonic eddies were observed near thé mouth on thé eastern side ofthe bay, adjacent to thé outflow. A simplified fractal dispersion model gives résidence times of 42 d similar to those obtained from a scaling analysis (30-40 d) and a diagnostic numerical model (30 d). RÉSUMÉ On décrit l'hydrographie et la circulation dans la baie Conception (T.-N.) en se basant sur des données hydrographiques, de courantomètres et de dériveurs enregistrées durant quatre ans (de 1988 à 1991). Les cycles saisonniers de température 6 à 13, TC) et de salinité (31 à 32,5) de la baie sont très près de ceux de la plate-forme voisine. On a observé un échange d'eau de fond en avril 1989. Un échange en eau profonde a eu lieu de la fin d'automne au début de l'hiver 1989/90. Les courants de marée sont faibles, 1 à 2 cm s~] pour les éléments A/2 et Kj. Les courants eulériens moyens observés (< 3 cm s~ ) sont plus petits que l'écart type ( 1 à 11 cm s~* ); toutefois, il y a un courant sortant persitant

The purpose of this work is to present a simplified model of cloud-droplet spectra that can be used as a tool for interpreting cloud microphysical observations in boundary-layer clouds, and as a way to begin quantifying the couplings between cloud microphysics, dynamics and radiative properties for eventual use in cloud parametrizations. The model is steady-state, ignores nucleation effects, and is formulated to produce horizontally averaged statistics. The major difference between this model and previous work lies in the model assumption that droplet spectra at a given level within a cloud are horizontal averages over a large number of air parcels, each of which can have a different lifting condensation level (LCL). Vertical motions are driven by buoyancy, so that liquid water and vertical velocity are simple functions of height above the LCL. This relationship, treated statistically over a large number of parcels, relates turbulent kinetic energy to horizontally averaged statistics of the droplet spectra. The broadening of droplet spectra is thus directly related to the turbulent kinetic energy within a cloud. In validating the model, results are compared with observations. It is shown that the basic droplet spectra predicted by the model are quite realistic for stratus and stratocumulus. The modelled droplet spectra broaden from cloud base to cloud top as is frequently observed, and the relationship between drop spectrum width and mean radius agrees quite well with observations.

Warming of the deep water in the Weddell Sea has important implications for Antarctic Bottom Water (AABW) formation, melting of pack ice, and the regional ocean-atmosphere heat transfer. In order to evaluate warming trends in the Weddell Sea, a historical data set encompassing CTD and bottle data from 1912 to 2000 was analyzed for temporal trends in the deep water masses: Warm Deep Water (WDW) and Weddell Sea Deep Water (WSDW). The coldest WDW temperatures were primarily associated with the Weddell Polynya of the mid-1970's. Subsequent warming occurred at a rate of ~0.012 ±0.007 o C yr -1 from the 1970's to 1990's. This warming was comparable to the global, average surface water warming observed by Levitus et al. [2000], to the warming of the WSBW in the central Weddell Sea observed by Fahrbach et al. [1998a], and to the surface ice temperature warming from 1970 to 1998 in the Weddell Sea observed by Comiso [2000]. The warming was not compensated by an increase in salinity and thus the WDW became less dense. The location of the warmest temperature was displaced towards the surface by ~200 m from the 1970's to the 1990's. Although the average Weddell Sea Deep Water (WSDW) potential temperatures between 1500 and 3500 m were warmer in the 1990's than in the 1970's, high variability in the data prevented identification of a well-defined temporal trend.

The authors establish the effect of urbanization on precipitation in the Pearl River Delta of China with data from an annual land use map (1988–96) derived from Landsat images and monthly climate data from 16 local meteorological stations. A statistical analysis of the relationship between climate and urban land use in concentric buffers around the stations indicates that there is a causal relationship from temporal and spatial patterns of urbanization to temporal and spatial patterns of precipitation during the dry season. Results suggest an urban precipitation deficit in which urbanization reduces local precipitation. This reduction may be caused by changes in surface hydrology that extend beyond the urban heat island effect and energy-related aerosol emissions.

The dynamics of the seagrass Zostera noltii in established and colonizing meadows were assessed in Ria Formosa lagoon, Southern Portugal. Shoot weight, above:belowground biomass ratio, flowering shoot density, meadow production, and biomass-density relationships were investigated. Results indicate that the species population dynamics differ clearly in different development stages of the meadows. The overall mean of flowering shoot density was five times higher in the colonizing (83 flowering shoots m)2) than in the established meadow (16 flowering shoots m)2), revealing a greater contribution of sexual reproduction during the species colonization process. The temporal variation of the biomass-density relationship in the colonizing meadow showed a cyclic seasonal trajectory, a wider range of data, and a simultaneous peak of biomass and density, suggesting no space limitations constraining the internal packing of shoots during the growing season. In the established meadow, density peaked before biomass in agreement to the dominant role of the clonal architecture of seagrasses in the configuration of closed meadows, suggesting the occurrence of self-thinning and ⁄ or regulation of ramet formation. Slope of the biomass-density relationships was similar in the established and colonizing meadows, generally suggesting similar nutritional conditions, regardless of their muddy and sandy sediments. Plants of the colonizing meadow invest mainly on the belowground fraction (above:belowground biomass ratio <1), as meadow expansion is mainly controlled by the elongation of horizontal rhizomes. The annual total production (1163 g C m)2 year)1) and the biomass turnover (34.8 year)1) were also higher in this meadow, corroborating the high investment of the species during the meadow expansion. The faster biomass turnover of the colonizing meadow implies a more limited capacity to accumulate biomass, indicating a greater exportation of organic carbon and nutrients to the coastal area. The different biomass turnover rates suggest different trophic and structural roles of Z. noltii communities in established and colonizing meadows.

~James Baker, in his introduction to a series of articles celebrating the 50th anniversary of the book The Ocrans (Sverdrup, Johnson, and Fleming, 1942), tells a story about starting in oceanography as a summer fellow at Scripps Institution of Oceanography (SIO) on an expedition with John Knauss. "Jot-ua told me that if I wanted to be an oceanographer, then I had to read The Oceans as a start." (Baker, 1992). Sverdrup, Johnson and Fleming's venerable 1942 book, The Oceans, provided an excellent text into the 1950s for graduate education in oceans sciences and was recommend reading when I began my graduate education in oceanography in the fall of 1968 at the Graduate School of Oceanography (GSO), University of Rhode Island (URI). The opening paragraph of The Oceans states:

The dynamics of the pressure distribution associated with the sea-breeze circulation is investigated. Analysis of hourly observations of surface pressure reveals that, on a typical sea-breeze day, large surface-pressure falls are recorded very far inland. Using a linear numerical model we show that this can only be understood when sound waves are taken into account. Sound waves are excited when air in the boundary layer over land expands due to diabatic heating. The numerical study reveals that vertically travelling sound waves induce a pressure increase through the entire atmosphere above the heated layer within a few minutes, while horizontally travelling sound waves induce a surface-pressure decrease over land and a surface-pressure increase over sea, with the resulting horizontal surface-pressure gradient initiating the sea breeze. Because the signal travels inland at the speed of sound (about 300 m s-I), points at a distance of more than lo00 km from the coast experience a surface-pressure decrease within an hour after the initiation of diabatic heating over land. The pressure decrease near the earth's surface over land, as well as the pressure increase aloft, is in accord with the observations at mountain stations and the analyses of the observed daytime surface-pressure changes in summer over the continent and adjacent seas. The implications of these findings for hydrostatic modelling of sea breezes are investigated. It appears that after one hour the hydrostatic sea breeze is 10% stronger than the non-hydrostatic sea breeze, while the hydrostatic return current is about 20% weaker.

El método FAO Penman (PM), es el más confiable para estimar la evapotranspiración de referencia (ETo) y es recomendado por la FAO como estándar para verificar otros métodos empíricos. En su utilización es necesaria información de cuatro parámetros meteorológicos: temperatura del aire, humedad relativa, velocidad del viento y radiación neta. La poca disponibilidad de estos parámetros limita el uso del método en muchos lugares; por lo que los modelos Thornthwaite (TM) y Hargreaves (HM) son usados con frecuencia, ya que únicamente se basan en medidas de temperatura del aire, medidas comunes en muchas estaciones meteorológicas en todo el mundo, por lo que son una opción para estimar la ETo. Sin embargo, con el objetivo de obtener resultados apropiados de ETo, los modelos HM y TM deben ser calibrados de acuerdo con las condiciones locales. En el presente estudio, los coeficientes originales de TM y HM son modificados para una calibración local en climas semi-áridos y tropicales sub-húmedos del estado de Yucatán, México, usando como estándar la ecuación Penman-de FAO. Se usaron datos meteorológicos de dos estaciones en el estado de Yucatán, México que corresponden a un clima costero semi-árido (Progreso) y a un clima tropical sub-húmedo tierra adentro (Mérida). En la comparación se analizaron los índices de concordancia (D), confianza (C), correlación (R) y regresión (R 2 ), así como indicadores del sesgo medio del error (MBE), raíz cuadrada media del error (RMSE), error relativo (RE) y el cociente entre ambas estimaciones promedio de ETo ( r). Usando HM sin ajuste se obtuvieron buenas estimaciones de ETo en Mérida y Progreso, con valores de C de 0.825 y 0.816, respectivamente. No se recomienda el uso de TM sin ajuste en ninguna de las estaciones meteorológicas estudiadas. Sin embargo, en ambas estaciones, el modelo TM estima mejor la Eto durante los meses lluviosos (de junio a octubre). En ambas estaciones meteorológicas, costera y de tierra adentro, se obtuvieron mejores estimaciones anuales de ETo con el uso de HM sin ajuste (valores de C de 0.906 y 0.917, respectivamente).

The Atlantic meridional overturning circulation (AMOC) has been observed continuously at 26 • N since April 2004. The AMOC and its component parts are monitored by combining a transatlantic array of moored instruments with submarine-cable-based measurements of the Gulf Stream and satellite derived Ekman transport. The time series has recently been extended to October 2012 and the results show a downward trend since 2004. From April 2008 to March 2012, the AMOC was an average of 2.7 Sv (1 Sv = 10 6 m 3 s −1 ) weaker than in the first four years of observation (95 % confidence that the reduction is 0.3 Sv or more). Ekman transport reduced by about 0.2 Sv and the Gulf Stream by 0.5 Sv but most of the change (2.0 Sv) is due to the mid-ocean geostrophic flow. The change of the mid-ocean geostrophic flow represents a strengthening of the southward flow above the thermocline. The increased southward flow of warm waters is balanced by a decrease in the southward flow of lower North Atlantic deep water below 3000 m. The transport of lower North Atlantic deep water slowed by 7 % per year (95 % confidence that the rate of slowing is greater than 2.5 % per year).

This study reports hydrographic and biological observations from three cruises where cyclonic and anticyclonic eddies were observed downstream of Gran Canaria island. Based on field data and remote sensing images (AVHRR and CZCS), two mechanisms associated with islandgenerated eddies, largely responsible for the formation and distribution of chlorophyll around the Canary Islands, are proposed. First, nutrient pumping and vertical uplifting of the deep chlorophyll maximum by cyclonic eddies might represent important sources of primary production in the oligotrophic waters of the Canary region. Second, eddies are responsible for the horizontal transport and distribution of chlorophyll originating near the islands or off the African coast. Water with high chlorophyll content, resulting from island stirring or local upwelling at the flanks of the islands, is incorporated into cyclonic eddies in their development and subsequently transported downstream. On the other hand, anticyclonic eddies can also entrain water rich in chlorophyll when interacting with the offshore boundary of the African coastal upwelling. This chlorophyll will be advected southward as the eddy drifts. The recurrence of cyclonic and anticyclonic eddies, together with the presence of upwelling filaments throughout the year, must have important biological consequences in the formation and transport of organic matter in the Canary region. 0 1997

Variations in the Atlantic meridional overturning circulation (AMOC) between 1979 and 2008 are documented using the operational ocean analysis, the Global Ocean Data Assimilation System (GODAS), at the National Centers for Climate Prediction (NCEP). The maximum AMOC at 40°N is about 16 Sv in average with peak-to-peak variability of 3-4 Sv. The AMOC variations are dominated by an upward trend from 1980 to 1995, and a downward trend from 1995 to 2008. The maximum AMOC at 26.5°N is slightly weaker than hydrographic estimates and observations from mooring array. The dominant variability of the AMOC in 20°-65°N (the first EOF, 51% variance) is highly correlated with that in the subsurface temperature (the first EOF, 33% variance), and therefore, with density (the first EOF, 25% variance) in the North Atlantic, and is consistent with the observational estimates based on the World Ocean Database 2005. The dominant variabilities of AMOC and subsurface temperature are also analyzed in the context of possible links with the net surface heat flux, deep convection, western boundary current, and subpolar gyre. Variation in the net surface heat flux is further linked to the North Atlantic Oscillation (NAO) index which is found to lead AMOC variations by about 5 years. Our results indicate that AMOC variations can be documented based on an ocean analysis system such as GODAS.

Climate variability and change are expected to influence the seasonal cycle in North Pacific sub-arctic marine ecosystems. The hypothesis that timing of nesting and productivity of piscivorous seabirds [kittiwakes (Rissa tridactyla and Rissa brevirostris) and murres (Uria aalge and Uria lomvia)] at the Pribilof Islands are related to variation in ocean climate as indexed by changes in sea-ice concentrations (SICs)

At-sea distributions of large scyphozoan jellyfish across the Irish Sea were studied using visual surface counts from ships of opportunity. Thirty-seven surveys were conducted along two[100 km long transects between Ireland and the UK from April to September in 2009 and 2010. Five species were recorded but only Aurelia aurita and Cyanea capillata were frequently observed. The first formal description of the seasonal changes in the abundances and distributions of these two species in the study area is provided. The highest densities of these species were more likely to be found *30 km offshore, but large aggregations were present both in coastal and offshore waters. Evidence for aggregations of medusae along physical discontinuities was provided by coupling jellyfish observations with simultaneous records of environmental parameters. The value of surveys from ships of opportunity as cost-effective semi-quantitative tools, to develop local knowledge on jellyfish abundance, distribution, and phenology is discussed.

The analyses of density fields, nitrate and chlorophyll a concentrations, Lagrangian current measurements and remote sensing of sea surface temperatures demonstrated an island mixing effect for Monhegan Island (Gulf of Maine). The island's unique location within the westward flowing arm of a counterclockwise basin gyre and hhe bathymetry surrounding the island result in a combination of vertical mixing and npwelling to produce chlorophyll maxima on the north and south flanks of the island.

In this paper, we have assessed the temporal, spatial and depth related variation of suspended particulate organic matter (POM) in the Bay of Bengal. For this purpose, suspended particulate matter (SPM) samples were collected from eight depths (2 to 1000 m) at 9 locations in the Bay of Bengal during July/August 2001 (Southwest monsoon, SWM), September/October 2002 (Fall Intermonsoon, FIM), and March/April 2003 (Spring Inter-monsoon, SPIM). The SPM samples were analyzed for chlorophyll a (Chl a), particulate organic carbon (POC) and total particulate nitrogen (TPN). The surface concentrations of POC varied from 4.3 to 11.1 µM C, 3.1 to 10.9 µM C, and 4.3 to 9.0 µM C during SWM, FIM, and SPIM, respectively. The levels of SPM, and the concentrations of Chl a, and POC were relatively higher in the offshore compared to the near shore stations, especially during SWM. The POC concentration and its contribution to the SPM were higher in the surface waters, and both decreased with increasing water column depth at most of the stations. The observed decrease with depth of POC indicates heterotrophic uptake and/or dilution by inorganic material, poor in POC. This was also reflected in the C/N ratio which generally increased with water column depth. The relatively low C/N and POC/Chl a ratios, and high Chl a and % POC during the SWM and FIM indicate the presence of relatively fresh POM in the Bay during these two seasons. The observed seasonal differences in the quality of POM appears to be governed by river runoff and the physical forces such as eddies which pump nutrients into the surface waters thereby enhancing biological production.

The continental shelf of Northeast Brazil is a unique geological region, consisting of shallow-water rhodolith beds. However, very little information exists about the complexity of this part of the continental shelf and its biogenic sedimentation. The present study analysed the characteristics of rhodoliths (size, shape and structure) and compares these characteristics with the associated sediments (Grain size, biogenic composition and percentage of CaCO3). The study area was located on a sandstone reef area on the inner continental shelf of Northeast Brazil. Our results show that recently dead rhodoliths are the main component of the pebble fraction with mean diameter near to 2 cm. The focal area is characterised by beds of rhodoliths, featuring individuals of all shapes (discoidal, ellipsoidal and spheroidal), with the ellipsoidal shape being the most abundant. The larger rhodoliths exhibited a near spheroidal shape, and their outer growth forms show high branching density (BIV). The associated sediment was predominantly composed of carbonate from marine fauna and flora, and calcareous algae contributed most to the sand fraction of the sediments. Foraminifera and molluscs were the most abundant biogenic fauna associated with the sediment. The grain size of the sediment was mostly medium and coarse carbonate sand. The results illustrate that there are correlations between the morphology of rhodoliths and the associated sediment. The biogenic composition of the sediment (Rhodophyta and Rizopoda) was correlated with different branching densities of rhodoliths (BII and BIV). The distribution of the sediment grain size also correlated with size, shape (diameter and sphericity) and structure (Branching BIII and BIV) of rhodoliths. Therefore, our results highlight that the correlations between associated sediment and diameter of rhodoliths is a reflection of the abiotic conditions, being principally determined by depth and hydrodynamic energy.

Cave diving is one of the most technical and potential dangerous forms of diving done today. It may involve use of multiple tanks, regulators and gas mixtures or rebreathers, in combination with powerful long-range diver propulsion vehicles, to penetrate thousands of meters into submerged cave systems where direct ascent to the surface in the case of emergencies is impossible. In order to carry out scientific studies under such difficult conditions, individuals must be highly competent and experienced cave divers. In spite of these problems, numerous scientific investigations in the fields of biology, ecology, microbiology, geology, hydrology and archaeology have carried out by cave diving scientists. Exploratory cave divers have provided the initial impetus for this research by exploring and mapping underwater caves.

A simple climate model has been developed to investigate the existence of the small ice cap instability in the Southern Hemisphere. The model consists of four coupled components: an atmospheric energy balance model, a thermodynamic snow-sea ice model, an oceanic mixed layer model and a terrestrial ice model. Results from a series of experiments involving different degrees of coupling in the model show that the instability appears only in those cases when an explicit representation of the Antarctic ice sheet is not included in the model. In order to determine which physical processes in the ice sheet model lead to a stabilization of the system we have conducted several sensitivity experiments in each of which a given ice sheet process has been removed from the control formulation of the model. Results from these experiments suggest that the feedback between the elevation of the ice sheet and the snow accumulation-ice ablation balance is responsible for the disappearance of the small ice cap instability in our simulation. In the model, the mass balance of the ice sheet depends on the air temperature at sea level corrected for altitude and it is, therefore, a function of surface elevation. This altitudemass balance feedback effectively decouples the location of the ice edge from any specific sea level isotherm, thus decreasing the model sensitivity to the albedotemperature feedback, which is responsible for the appearance of the instability. It is also shown that M. A. Morales Maqueda ()) A

In recent years, there has been an increasing intensity of human use of coastal areas in Galicia (NW Spain). Actually, there is great concern about rapid and unplanned urban and industrial development on certain locations, as this can generate adverse impacts on those areas. In this study, we selected three sandy beaches along the Galician coast (Chanteiro, Insuela and Valieros) facing different levels of anthropic pressure, and we analysed Talitrus saltator individuals with the aim of elucidating whether anthropogenic pressures on beaches such as tourism or pollution have an influence on the incidence of morphological developmental alterations in sandhoppers in the field. Specifically, levels of fluctuating asymmetry were selected as indicators of environmental stress. Results of two sampling dates (May and September) show that individuals collected at the most touristy and polluted beach were those showing the highest asymmetry values, although results were only statistically significant for samples collected during spring. Results are in accordance with the hypothesis that beach management and pollution reduce symmetry in sandhoppers living in altered beaches.

Most of our knowledge about deep-sea habitats is limited to bathyal (200-3000 m) and abyssal depths (3000-6000 m), while relatively little is known about the hadal zone (6000-11,000 m). The basic paradigm for the distribution of deep seafloor biomass suggests that the reduction in biomass and average body size of benthic animals along depth gradients is mainly related to surface productivity and remineralisation of sinking particulate organic carbon with depth. However, there is evidence that this pattern is somewhat reversed in hadal trenches by the funnelling of organic sediments, which would result in increased food availability along the axis of the trenches and towards their deeper regions. Therefore, despite the extreme hydrostatic pressure and remoteness from the pelagic food supply, it is hypothesized that biomass can increase with depth in hadal trenches. We developed a numerical model of gravitational lateral sediment transport along the seafloor as a function of slope, using the Kermadec Trench, near New Zealand, as a test environment. We propose that local topography (at a scale of tens of kilometres) and trench shape can be used to provide useful estimates of local accumulation of food and, therefore, patterns of benthic biomass. Orientation and steepness of local slopes are the drivers of organic sediment accumulation in the model, which result in higher biomass along the axis of the trench, especially in the deepest spots, and lower biomass on the slopes, from which most sediment is removed. The model outputs for the Kermadec Trench are in agreement with observations suggesting the occurrence of a funnelling effect and substantial spatial variability in biomass inside a trench. Further trench surveys will be needed to determine the degree to which seafloor currents are important compared with the gravity-driven transport modelled here. These outputs can also benefit future hadal investigations by highlighting areas of potential biological interest, on which to focus sampling effort. Comprehensive exploration of hadal trenches will, in turn, provide datasets for improving the model parameters and increasing predictive power.

An amplification of random perturbations by the interaction of non-linearities internal to the climatic system with external, orbital forcing is found. This stochastic resonance is investigated in a highly simplified, zero-dimensional climate model. It is conceivable that this new type of resonance might play a role in explaining the lo5 year peak in the power spectra of paleoclimatic records.

Dynamic Energy Budget (DEB) theory provides a powerful framework for interpreting toxicity data, but is not broadly applied in ecotoxicology yet. One of the reasons is the fact that estimation of DEB parameters from experimental data is certainly not a trivial affair. Almost every data analysis raises new questions, which require the formulation of specific mechanistic hypotheses. These hypotheses should be translated into model adaptations, which can subsequently be tested on the data set. In this paper, we demonstrate this procedure by analyzing a case study for ecotoxicity within the DEB framework. The case study we selected is a previously published data set for 4-n-nonylphenol in the polychaete worm Capitella teleta (formerly Capitella sp. I). Particular aspects of interest in this study are an apparent slow initial growth, and low-dose stimulation (hormesis) of growth and reproduction. In this publication, we explicitly discuss our deviations from the standard DEB model in terms of the underlying hypotheses, the existence of alternative hypotheses to explain the data, and how limited additional experiments can be designed to decide between alternative explanations.

The observed nature of buildup and collapse of warm pool in the eastern Arabian Sea and the Bay of Bengal is examined with help of sea surface temperature (SST) data collected by NIOT buoy network during the period 1998-2008. During the buildup phase, the SSTs showed a progressive increase in both the eastern Arabian Sea and the Bay of Bengal. During this phase, the amplitudes of the diurnal oscillations of SST are relatively larger in the Bay of Bengal compared to those in the Arabian Sea. During the collapse phase, the SST cooling was dramatic in the eastern Arabian Sean caused by the monsoon onset vortex. Relatively larger amplitude intraseasonal oscillations are seen only in the Bay of Bengal and off the southwest coast of India during the collapse phase.

Radiative forcing is a useful diagnostic quantity for indicating the size of climate change mechanisms, and for interpreting the results of General Circulation Model (GCM) experiments. It is also ideal for exploring the potential sensitivity of climate change simulations to assumptions regarding, for example, the horizontal and vertical distribution of changes in greenhouse gases, as a guide to whether these effects need to be incorporated into GCMs. This paper examines this issue for a range of greenhouse gases, and also examines the dependence of the forcing on horizontal averaging and the definition of tropopause position.

Extensive areas of methane-derived authigenic carbonate (MDAC) have been mapped in the Irish Sea. In the Irish Sector, 23 seabed mounds associated with the Codling Fault Zone were identified by multi-beam echo sounder mapping. Inspection by ROV-mounted video showed that these mounds are rocky features rising 5–10 m above the normal seabed; sampling showed that they are comprised of quartz grains bound together by carbonate cement, probably MDAC. Two separate locations have been mapped in the UK Sector. At Texel 11, seabed mounds and a 6–8 m high cliff were mapped geophysically (MBES, SSS and seismic profiler surveys). Video surveys showed that both the mounds and the cliff are rocky reefs colonised by a prolific fauna. Samples proved to be carbonate-cemented sediments, and carbon isotope analysis (δ13C −41 to −46% PDB) showed that the cement was MDAC. Similar surveys of the Holden’s Reefs area proved the presence of similar rocky reefs which are also cemented by MDAC. The total area covered by these two MDAC occurrences is estimated to be >500,000 m2. These MDAC occurrences are comparable in nature and formation to the ‘bubbling reefs’ of the Kattegat. As the bubbling reefs are “seabed features formed by leaking gas”, one of the marine habitats identified by the European Commission’s Habitats Directive as being sensitive and worthy of protection, it is suggested that the Irish Sea carbonate reefs should also be considered as special habitats.

The photophores of Meganyctiphanes were investigated with regard to the control of light production and with respect to their role in a hitherto unknown communication system using light flashes which became evident from observation of specialised signalling behaviour. To that purpose the light production was recorded during presentation of a range of stimuli delivered to the intact, tethered shrimp. Stimuli used were changes in ambient light, water turbulence, simulated predator approach and light flashes, as well as electric shocks and serotonin injections. Strong negative light gradients, exaggerating the natural sunset signal, reliably elicited light production, the peak of which lasted on average 2 min. In the late phase of this light production, low frequency water oscillations and turbulent flow (assumed intraspecific communication signals at close range) elicited transient increases in light production. Artificial light flashes presented to a group of shrimp evoked a signalling behaviour in which the animal points the light of its photophore beamers (positioned at the ventral side and normally directed downwards) for a fraction of a second at observers within the same depth level. The responses produced by the signalling behaviour indicate a fixed delay with respect to the triggering flash. Electric stimulation of the ventral nerve cord via implanted electrodes resulted in a strong light production with a latency of 160 ms. Injection of serotonin, resulting in haemolymph concentrations of 10–5 M and higher, initiated increasingly strong and increasingly long-lasting continuous light production. Implications for the control of the photophores are discussed.

We studied the foraging behavior and marine habitats used by Laysan (Phoebastria immutabilis) and Black-footed (Phoebastria nigripes) Albatrosses, during four consecutive breeding seasons to investigate whether these marine predators changed habitat preferences, foraging distributions, or both, in accordance with natural interannual variability in the marine environment. We used satellite telemetry to track a total of 37 Laysan and 36 Black-footed Albatrosses during the incubation periods of 2002-2006 at Tern Island, Northwest Hawaiian Islands. First passage time analysis was used to determine search effort of individual albatrosses along their respective tracks, and this metric was then related to oceanographic habitat variables using linear mixed-effects regression. The majority of individuals traveled to pelagic waters of the North Pacific, with Laysan Albatrosses demonstrating a more northwesterly distribution from the breeding colony. Laysan Albatrosses traveled farther, for longer periods, and demonstrated greater interannual variability in trip characteristics than Black-footed Albatrosses. For Laysan Albatrosses, maximum trip distance was negatively correlated with body mass change during foraging and overall breeding success. There was considerable interspecific segregation of foraging habitats, and low overlap of foraging distributions between years. For all years, and both species, sea surface temperature was consistently the most important environmental variable predicting search effort of albatrosses, suggesting that both species use similar environmental cues when searching for prey. In the context of climate variability, our results suggest that Hawaiian albatrosses demonstrate flexibility in foraging strategies and track preferred marine habitats. However, adjusting foraging behavior to climatic variability may have energetic, and subsequent reproductive consequences.