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Background Coronavirus disease 2019 (COVID-19) has been associated with a range of cardiovascular manifestations, including myocardial injury and thrombo-embolism. Pulmonary embolism (PE) causing anteroseptal/anterior ST elevations that mimic myocardial infarction have previously been described. This phenomenon is thought to be related to right ventricular injury from large emboli. Case summary A 48-year-old woman with history of type 2 diabetes mellitus and hypertension presented to her local hospital with fever, cough, nausea, and dyspnoea. A test for SARS-CoV-2 was taken, and she was discharged with instructions to self-quarantine. She was subsequently notified of a positive SARS-CoV-2 result. Three days later, she re-presented with worsening dyspnoea and respiratory failure requiring intubation. On hospital Day 6, she became acutely hypoxic and hypotensive. Telemetry was noted to have ST changes, prompting ECG that revealed sinus tachycardia with prominent new ST elevations in her precordial leads. Transthoracic echocardiogram showed normal left ventricular function; however, the right ventricle was moderately dilated with positive McConnell’s sign. Due to her unstable clinical state and high suspicion for PE, she was treated with tenecteplase 50 mg i.v. with complete resolution of her ST elevations and improved oxygenation. Discussion Given the high rates of thrombo-embolic events in COVID-19 patients, PE should be in the differential diagnosis of ST elevation, particularly in younger patients with few risk factors for coronary artery disease.

Patients with massive and submassive pulmonary embolism (PE) require rapid identification, triage, and consideration for reperfusion therapy. Use of an existing ST-segment elevation myocardial infarction (STEMI) team and activation protocol may be an effective means to care for these patients.The objective of this analysis was to evaluate a pilot study using the STEMI team and a dedicated PE protocol for treatment of patients with massive and submassive PE.From June 2014 to April 2016, a total of 40 patients with massive and submassive PE were evaluated. Baseline demographics, mode of hospital entry (transfer-in, in-hospital, and emergency department [ED] arrival), treatment time intervals (door to computed tomography PE protocol [CTPE], CTPE to invasive pulmonary angiogram, door to treatment time), procedures performed, and in-hospital clinical events were collected.Mean age was 56 ± 14 years, 17 (42%) were male, and 12 (30%) had a prior history of deep venous thrombosis or PE. Twenty-three patients (57%) had massive PE and 17 patients (43%) had submassive PE. Mode of hospital entry was transfer-in (38%), in-hospital (20%), and ED arrival (42%). Four patients (10%) presented with cardiac arrest, 8 patients (20%) required intubation, and 5 patients (12%) required extracorporeal membrane oxygenation. Ten patients (25%) received anticoagulation therapy or placement of inferior vena cava filter, 3 patients (7.5%) received diagnostic pulmonary angiography alone, and 27 patients (67.5%) received endovascular treatment. For patients arriving via the ED, door to CTPE was 4.9 ± 3.6 hours, CTPE to diagnostic pulmonary angiography was 7.8 ± 8.5 hours, and door to treatment time was 10.2 ± 9.0 hours. Endovascular devices utilized included combinations of rheolytic and other thrombectomy devices as well as catheter-directed fibrinolysis. Length of hospital stay was 15 ± 15 days and in-hospital survival rate was 90%.Use of an existing STEMI team and activation protocol is a feasible method to care for patients with massive and submassive PE. This pilot study demonstrated rapid treatment times with low in-hospital mortality.

The production of uniform-sized and multilayer microbubbles enables promising medical applications that combine ultrasound contrast and targeted delivery of therapeutics, with improvements in the consistency of acoustic response and drug loading relative to non-uniform populations of microbubbles. Microfluidics has shown utility in the generation of such small multi-phase systems, however low production rates from individual devices limit the potential for clinical translation. We present scaled-up production of monodisperse dual-layered microbubbles in a novel multi-array microfluidic module containing four or eight hydrodynamic flow-focusing orifices. Production reached 1.34 × 10(5) Hz in the 8-channel configuration, and microbubble diameters in the high-speed regime (> 5 × 10(4) Hz) ranged between 18.6-22.3 μm with a mean pooled polydispersity index under 9 percent. Results demonstrate that microfluidic scale-up for high-output production of multilayer bubbles is possible while maintaining consistency in size production, suggesting that this method may be appropriate for future clinical applications.

Coastal seas are critical components of the global carbon cycle, yet little research has been conducted on the impact of ocean acidification on coastal benthic organisms. Calcifying marine organisms are predicted to be most vulnerable to a decline in oceanic pH (ocean acidification) based on the assumption that calcification will decrease as a result of changes in seawater carbonate chemistry, particularly reduced carbonate ion concentration (and associated saturation states). Net calcium carbonate production is dependent on an organism's ability to increase calcification sufficiently to counteract an increase in dissolution. Here, a critical appraisal of calcification in five benthic species showed, contrary to popular predictions, the deposition of calcium carbonate can be maintained or even increased in acidified seawater. This study measured changes in the concentration of calcium ions seen in shells taken from living animals exposed to acidified seawater. These data were compared with data f...

The Arctic Ocean currently has the highest global average pH. However, due to increasing atmospheric CO2 levels, it will become a region with one of the lowest global pH levels. In addition, Arctic waters will also increase in temperature as a result of global warming. These environmental changes can pose a significant threat for marine species, and in particular true Arctic species that are adapted to the historically cold and relatively stable abiotic conditions of the region. Consequently, we investigated some key physiological responses of brittlestar Ophiocten sericeum, a polar endemic which can dominate benthic infauna, to a temperature increase of 3.5°C (ambient, 5–8.5°C) and CO2 induced reduction in pH of 0.6 units (pH 7.7) and 1 unit (pH 7.3) below ambient (pH 8.3). Metabolism was upregulated at low pH. Faster arm regeneration stimulated by increased temperature was counteracted by low pH; at pH 7.3 in the high-temperature treatment, the maintenance of calcium carbonate structures in undersaturated conditions resulted in reduction in the rate of arm regeneration, possibly due to accelerated the use of energy reserves. If so, this could result in an energy deficit at times of increased energetic costs associated with responding to the combined factors of high temperature and low pH.

The global ocean and atmosphere are warming. There is increasing evidence suggesting that, in addition to other environmental factors, climate change is affecting species distributions and local population dynamics. Additionally, as a consequence of the growing levels of atmospheric carbon dioxide (CO2), the oceans are taking up increasing amounts of this CO2, causing ocean pH to decrease (ocean acidification). The relative impacts of ocean acidification on population dynamics have yet to be investigated, despite many studies indicating that there will be at least a sublethal impact on many marine organisms, particularly key calcifying organisms. Using empirical data, we forced a barnacle (Semibalanus balanoides) population model to investigate the relative influence of sea surface temperature (SST) and ocean acidification on a population nearing the southern limit of its geographic distribution. Hindcast models were compared to observational data from Cellar Beach (southwestern United Kingdom). Results indicate that a declining pH trend (-0.0017 unit/yr), indicative of ocean acidification over the past 50 years, does not cause an observable impact on the population abundance relative to changes caused by fluctuations in temperature. Below the critical temperature (here T(crit) = 13.1 degrees C), pH has a more significant affect on population dynamics at this southern range edge. However, above this value, SST has the overriding influence. At lower SST, a decrease in pH (according to the National Bureau of Standards, pHNBs) from 8.2 to 7.8 can significantly decrease the population abundance. The lethal impacts of ocean acidification observed in experiments on early life stages reduce cumulative survival by approximately 25%, which again will significantly alter the population level at this southern limit. Furthermore, forecast predictions from this model suggest that combined acidification and warming cause this local population to die out 10 years earlier than would occur if there was only global warming and no concomitant decrease in pH.

The Arctic Ocean and its associated ecosystems face numerous challenges over the coming century. Increasing atmospheric CO2 is causing increasing warming and ice melting as well as a concomitant change in ocean chemistry (“ocean acidification”). As temperature increases it is expected that many temperate species will expand their geographic distribution northwards to follow this thermal shift; however with the addition of ocean acidification this transition may not be so straightforward. Here we investigate the potential impacts of ocean acidification and climate change on populations of an intertidal species, in this case the barnacle Semibalanus balanoides, at the northern edge of its range. Growth and development of metamorphosing post-larvae were negatively impacted at lower pH (pH 7.7) compared to the control (pH 8.1) but were not affected by elevated temperature (+4 °C). The mineral composition of the shells did not alter under any of the treatments. The combination of reduced growth and maintained mineral content suggests that there may have been a change in the energetic balance of the exposed animals. In undersaturated conditions more mineral is expected to dissolve from the shell and hence more energy would be required to maintain the mineral integrity. Any energy that would normally be invested into growth could be reallocated and hence organisms growing in lowered pH grow slower and end up smaller than individuals grown in higher pH conditions. The idea of reallocation of resources under different conditions of pH requires further investigation. However, there could be long-term implications on the fitness of these barnacles, which in turn may prevent them from successfully colonising new areas.

Ocean acidification and global warming are occurring concomitantly, yet few studies have investigated how organisms will respond to increases in both temperature and CO2. Intertidal microcosms were used to examine growth, shell mineralogy and survival of two intertidal barnacle post-larvae, Semibalanus balanoides and Elminius modestus, at two temperatures (14 and 19°C) and two CO2 concentrations (380 and 1,000 ppm), fed with a mixed diatom-flagellate diet at 15,000 cells ml−1 with flow rate of 10 ml−1 min−1. Control growth rates, using operculum diameter, were 14 ± 8 μm day−1 and 6 ± 2 μm day−1 for S. balanoides and E. modestus, respectively. Subtle, but significant decreases in E. modestus growth rate were observed in high CO2 but there were no impacts on shell calcium content and survival by either elevated temperature or CO2. S. balanoides exhibited no clear alterations in growth rate but did show a large reduction in shell calcium content and survival under elevated temperature and CO2. These results suggest that a decrease by 0.4 pH(NBS) units alone would not be sufficient to directly impact the survival of barnacles during the first month post-settlement. However, in conjunction with a 4–5°C increase in temperature, it appears that significant changes to the biology of these organisms will ensue.

The effects of CO2-induced acidification on survival, shell mineralogy, embryonic devel- opment and the timing of larval release were investigated in the intertidal barnacle Semibalanus bal- anoides using an intertidal microcosm system. Compared to that in the control (CO2 = 344 ppm, pH = 8.07), adult survival was 22% lower in the high-CO2 treatment (CO2 = 922 ppm, pH = 7.70) and sig- nificant changes in the mineral structure of the adult shell were observed. Embryonic development rate was significantly slower in the high-CO2 treatment than in the control but still resembled 'nat- ural' rates seen in populations found in similar locations. There was an estimated 19 d delay in devel- opment under high-CO2 conditions, which resulted in a 60% reduction in the number of nauplii reaching hatching stage at the time when over 50% of the control nauplii had hatched. We conclude that ocean acidification could potentially further compromise embryonic development in a species already stressed by temperature, which could in turn impact naupliar development and recruitment. S. balanoides, the adults of which live in a highly variable environment, has been shown to be detri- mentally impacted by a chronic change in chemical conditions (pH lowered beyond the current range) over a crucial period in their life cycle. Under experimental high-CO2 conditions, some adults were able to survive and larvae were able to hatch. This may indicate that there is still potential for organisms to find suitable habitats and for populations to develop and survive.

Macroecology provides a novel conceptual framework for analysis of the distribution and abundance of organisms at very large scales. Its rapid development in recent years has been driven primarily by studies of terrestrial taxa; the vast potential of marine systems to contribute to the macroecological research effort remains largely untapped. International collaborative efforts such as MarBEF have provided fresh impetus to the collation of regional databases of species occurrences, such as the newly available MacroBen database of the European soft sediment benthic fauna. Here, we provide a first macroecological summary of this unique database. We show that in common with almost all previously analysed assemblages, the frequency distribution of regional site occupancies across species in the MacroBen database is strongly right-skewed. More unusually, this right skew remains under logarithmic transformation. There is little evidence for any major differences between higher taxa in this frequency distribution (based on the 8 animal classes for which we have sufficient data). Indeed, considerable variation in occupancy persisted across the taxonomic hierarchy, such that most variation occurred between species within genera. There was a weak positive relationship between local population density and regional occupancy across species, but this abundance–occupancy relationship varied considerably between higher taxa and between geographical areas. Our results highlight the potential of databases such as MacroBen to consolidate macroecological generalities and to test emerging theory.

The pan-European MacroBen database was used to compare the AZTI Marine Biotic Index (AMBI) and the Benthic Quality Index (BQIES), 2 biotic indices which rely on 2 distinct assessments of species sensitivity/tolerance (i.e. AMBI EG and BQI E[S]0.05) and which up to now have only been compared on restricted data sets. A total of 12 409 stations were selected from the database. This subset (indicator database) was later divided into 4 marine and 1 estuarine subareas. We computed E(S50)0.0 in 643 taxa, which accounted for 91.8% of the total abundances in the whole marine indicator database. AMBI EG and E(S50)0.05 correlated poorly. Marked heterogeneities in E(S50)0.0 between the marine and estuarine North Sea and between the 4 marine subareas suggest that sensitivity/tolerance levels vary among geographical areas. High values of AMBI were always associated with low values of BQIES, which underlines the coherence of these 2 indices in identifying stations with a bad ecological status (ES). Conversely, low values of AMBI were sometimes associated with low values of BQIES resulting in the attribution of a good ES by AMBI and a bad ES by BQIES. This was caused by the dominance of species classified as sensitive by AMBI and tolerant by BQIES. Some of these species are known to be sensitive to natural disturbance, which highlights the tendency of BQIES to automatically classify dominant species as tolerant. Both indices thus present weaknesses in their way of assessing sensitivity/tolerance levels (i.e. existence of a single sensitivity/tolerance list for AMBI and the tight relationship between dominance and tolerance for BQIES). Futurestudies should focus on the (1) clarification of the sensitivity/tolerance levels of the species identifiedas problematic, and (2) assessment of the relationships between AMBI EG and E(S50)0.05 within and between combinations of geographical areas and habitats.

In recent years the non-native polychaete Sternaspis scutata has rapidly expanded its range in inshore muddy sediments along the coast of SW England (UK). To determine the impact the arrival of this moderately large infaunal deposit feeding polychaete could have on benthic biodiversity and ecosystem function, a mesocosm experiment has been conducted. Sternapsis scutata were added to undisturbed sediment cores containing natural fauna. Individuals of S. scutata were added at densities 2x and 10x the current abundance of this species at the collection site in Plymouth Sound. Nutrient fluxes and macrobenthic diversity were assessed after a period of fifty days. Despite the very large increase in biomass caused by the addition of S. scutata to the sediment cores there was no significant difference in the diversity of the resident benthic biota in treated cores. It is concluded that despite its size, the relative immobility of S. scutata dictates that its presence has little impact on the species around it. The addition of this species did significantly reduce the release of nitrite (NO2-) and increase the release of ammonium (NH4+) from the sediment. These findings support the assertion that the relationship between biodiversity and ecosystem functioning is idiosyncratic.

In addition to the predicted rise in temperature, a recognised consequence of increased atmospheric CO2 is ocean acidification. The response of marine organisms to the stresses associated with acidification is still not understood, and a number of recent experiments have addressed this problem. The starting point for many of these studies has been the development of a system by which seawater pH can be altered and then maintained. The current paper presents details of a tempera- ture- and pH-controlled microcosm system, which enables the establishment of a tidal regime, for the experimental investigation of intertidal organisms. Two climate scenarios were simulated to evaluate the system's precision and accuracy; Year 2008 ('low' (CO2): 380 ppm and 14°C) conditions and Year 2100 ('high' (CO2)) conditions (based on the IPCC—Intergovernmental Panel on Climate Change— 2007 A2 scenario, 'high' (CO2): 1250 ppm and 2.0 to 5.4°C warming). The temperature and seawater carbonate chemistry were reliably maintained for 30 d during which time newly settled barnacle cyprids were allowed to metamorphose into juveniles, then grow and develop. The pH and (CO2) had 95% confidence intervals of ±0.03 units and ±17 ppm, respectively, under low (CO2) conditions, and of ±0.02 units and ±43 ppm, respectively, under high (CO2) conditions. The tidal regime is fully adjust- able, and on this occasion was set to a 6 h cycle. These microcosms have proved ideal for studying ben- thic organisms from a variety of near-surface environments and at different stages of their life-cycle.

Since the rate of global climate change began to accelerate in the 1980s, the coastal seas of Britain have warmed by up to 1°C. Locations close to the northern range edges of a southern trochid gastropod Osilinus lineatus in Britain previously surveyed in the 1950s and 1980s were resurveyed during 2002–2004 to determine whether changes in the success of near-limit populations had occurred during the period of climate warming. Between the 1980s and the 2000s, the range limits had extended by up to 55 km. Populations sampled over a latitudinal extent of 4 degrees from northern limits towards the centre of the range showed synchronous increases in abundance throughout the years sampled, suggesting a large-scale factor such as climate was driving the observed changes. These increases in abundance and changes in range limits are likely to have occurred via increased recruitment success in recent years.

The diversity of soft-bottom polychaete assemblages in one Antarctic (Admiralty Bay) and two Arctic (Kongsfjord and van Mijenfjord) localities was compared. The data sets included 79 (Admiralty Bay), 80 (Kongsfjord) and 44 (van Mijenfjord) samples collected with use of 0.1 m2 van Veen grab. The number of species per sample in Kongsfjord (mean 19.9 ± 8.0 SD) was higher than that in Van Mijenfjord (13.7 ± 8.3) or Admiralty Bay (15.7 ± 9.4). The differences in species numbers reflected differences in numbers of individuals in samples: 310.4 ind/0.1 m2 ± 178.0 in Kongsfjord, 132.7 ind/0.1 m2 ± 88.7 in Van Mijenfjord and 138.9 ind/0.1 m2 ± 91.5 in Admiralty Bay. The Hurlbert diversity for 50 individuals (ES[50]) was similar at all sites: 10.7 ± 3.4 in Kongsfjord, 9.7 ± 4.2 in van Mijenfjord, 10.5 ± 4.9 in Admiralty Bay. The shape of species accumulation curves was also similar for all localities. There was no significant difference (at P < 0.05) either in the total number of species or in species richness as estimated by Chao1 and Chao2 estimators. The generic and family richness at three sites was also similar. We found no substantial differences in the distribution of species among families. At both poles Terebellidae, Ampharetidae, Maldanidae, Spionidae and Polynoidae were dominant in terms of species numbers. The similarity of infaunal polychaete diversity at the polar sites studied contrasts with the substantial differences reported for epi-megafauna. Our study suggests that the patterns of diversity of polar benthic communities are shaped by patterns of habitat heterogeneity which appears to mask any historical processes.

The activity of Arctic tidal glaciers results in high turbidity, high rate of inorganic particulate sedimentation and sedimentary instability in near-glacier marine basins. The chronic physical disturbance of sediments is accompanied by low input levels of organic matter. The response of soft-bottom macrofauna to glacial disturbance was studied in Kongsfjord, Svalbard. The quantita- tive characteristics of the macrofauna of 4 associations located along a gradient of glacier-induced disturbance were examined. Benthic biomass decreased with increased proximity to the glacier (from 10.9 g wet weight (ww) m -2 in the outermost association to 2.7 g ww m -2 in the glacial bay). Faunal density was highest in the transitional zone (592 ind. 0.1 m -2 ) between the central basin (425 ind. 0.1 m -2 ) and the inner glacial bay (442 ind. 0.1 m -2 ). The average individual biomass was lowest in the glacial bay as a result of the smaller body size of organisms. A decrease in the size of organisms in disturbed sites was not accompanied by a classical shift from 'equilibrium' to 'opportunistic' species. The functional structure of the faunal associations was simplified in the impoverished glacial bay association where 1 guild, the mobile surface-detritus feeders, strongly dominated. Average species number per sample was lowest in the glacial bay (22 species) and highest in the transitional associa- tion (42 species). Species diversity expressed by the Shannon-Wiener and Hurlbert rarefaction indices and evenness expressed by the Pielou index was lower in the glacial bay than in the remain- ing associations. The decrease in biomass, mean size of organisms, species diversity and evenness as well as the peaked distribution (i.e. maximum in the transitional zone) of density and species richness are consistent with patterns reported in studies of different natural and anthropogenic disturbances. Some distinct features of the case of glacial-induced disturbance include relatively high taxonomic distinctness and low beta diversity and low faunal dispersion in the near-glacier association.

High-latitude seas are mostly covered by multi-year ice, which impacts processes of primary production and sedimentation of organic matter. Because of the warming effect of West Spitsbergen Current (WSC), the waters off West Spitsbergen have only winter ice cover. That is uncommon for such a high latitude and enables to separate effects of multiyear-ice cover from the latitudinal patterns. Macrofauna was sampled off Kongsfjord (791N) along the depth gradient from 300 to 3000 m. The density, biomass and diversity at shallow sites situated in a canyon were very variable. Biomass was negatively correlated with depth (R ¼� 0:86; po0.001), and ranged from 61 g ww m � 2 (212 m) to 1 g ww m � 2 (2025 m). The biomasses were much higher than in the multiyear-ice covered High Arctic at similar depths, while resembling those from temperate and tropical localities. Species richness (expressed by number of species per sample and species–area accumulation curves) decreased with depth. There was no clear depth-related pattern in diversity measures: Hurbert rarefaction, Shannon–Wiener or Pielou. The classic increase of species richness and diversity with depth was not observed. Species richness and diversity of deep-sea macrofauna were much lower in our study than in comparable studies of temperate North Atlantic localities. That is related to geographic isolation of Greenland–Icelandic–Norwegian (GIN) seas from the Atlantic pool of species. r 2004 Elsevier Ltd. All rights reserved.

By the end of the 21st century models of climate change predict that the air temperature over most of the British Isles will increase by between 2 and 3 °C and sea-level will rise by 40–50 cm. Over that period it will become windier and mean wave height will increase, as will the frequency of storms. These changes in climate and weather will impact the intertidal zone of the UK and will cause distribution changes in many of the common invertebrate species that live there. Where these changes are severe they may well impact on patterns of distribution of ducks and wading birds. In the British Isles a number of organisms live close to their geographical limits of distribution. Some of these species might be expected to extend their range as climatic restraints are relaxed. Species currently limited by cool summers or winter cold will move northwards. In most cases the effects on the distribution of waterbirds will be small. For example, the replacement of the Northern Limpet Patella vulgata by the Southern Limpet P. depressa is unlikely to adversely affect Eurasian Oystercatchers Haematopus ostralegus. Of wider concern is the possibility that as climate warms the abundance and productivity of brown algae will decrease. This is likely to have two significant effects for waders. First, it would represent a loss of potentially rich feeding grounds for species such as Ruddy Turnstone Arenaria interpres that feed on small easily desiccated invertebrates living on or below the seaweed. Secondly, as algae die or are broken away the resulting debris is exported to sediment habitats where it considerably boosts the in situ production of bacteria at the base of the food web. An increase in sea-level will only have a major impact on the extent of rocky shore invertebrate communities where shore topography prevents the upward migration of the biota. Where a seawall limits shores, for example, biological production will be curtailed as the area available for colonization decreases. Increases in the size of waves and the frequency of storms will mimic increasing exposure and there will be a significant reduction in algal production in areas that are affected.

The relative impact on macrofaunal diversity of 7 naturally co-occurring bioturbators has been examined in a benthic mesocosm experiment. The bioturbators chosen were selected because of their potential vulnerability to the disturbances associated with demersal trawling. The experiment was conducted at the Solbergstrand mesocosm (Norwegian Institute for Water Research) using subtidal sediment collected from Bjornehodebukta, a small sheltered bay in the Oslofjord. For 3 of the bioturbating species (Brissopsis lyrifera, Aphrodita aculeata and Amphiura chiajei) a positive, linear relationship was demonstrated between bioturbator abundance and measures of species rich- ness (number of species and Margalef species richness). It was suggested that the presence of these bioturbating species increased oxygen penetration into the sediment, leading to an enhancement in the ability of benthic systems to process organic material. This had a beneficial effect on the associ- ated fauna in terms of maintaining levels of diversity. For Nephtys caeca, highest species diversity was seen in the low abundance treatments. Predation by N. caeca on small polychaetes is proposed as a possible explanation of the lower diversity in high-density treatments. It is concluded that B. lyrifera, A. aculeata, A. chiajei and N. caeca are functionally similar with respect to setting the diversity of the associated macrobenthic community and may therefore fulfill the same role within the benthic ecosystem. The presence of Calocaris macandreae, Nuculana minuta and Astarte sulcata had no detectable effect on diversity. Trawling has been shown to reduce the abundance of bioturbating species, and the current study demonstrates important implications of this loss on the maintenance of diversity. In addition, the interactions between bioturbation, diversity and organic enrichment high- light the need for management of anthropogenic impacts within the coastal environment in a holistic way rather than by isolation.

A multi-scale study of patterns of biodiversity of the fauna of the upper basin of the Kongsfjord, Svalbard (78°55′N, 11°56′E) revealed that there were low rates of species turnover at distances in excess of 2 km. Where patterns within the assemblage were detected, they were largely the result of changing patterns of dominance within a restricted species pool of, for the most part, small-bodied animals. There are relatively few hierarchical studies of species turnover at the scale we have reported and all report different spatial relationships between faunal similarity and separation of the samples. It is strongly recommended that comparative measures of species turnover, estimates of the size of species pools, or comparative estimates of species diversity should include information on the spatial distribution, relative to habitat patchiness, of the samples considered.

The spatial scale of megafaunal assemblage variation in apparently homogeneous subtidal sediment was investigated using quantitative observations from a remotely operated vehicle (ROV). Quantitative abundance estimates of surface-dwelling megafauna and biotic sediment features associated with burrowing megafauna were derived from video images using the Automated Benthic Image-Scaling System (ABISS), a novel method of applying scale to images collected by ROVs. Spatially referenced images were collected with a maximum sample separation of 400 m within a broader area of apparently homogeneous sediment in Plymouth Sound (Devon, UK) during May 2000 and March 2001. Rank-correlograms were constructed to examine the extent and form of the megafaunal spatial structure. The megafaunal assemblage was neither uniformly distributed nor temporally stable. A hierarchy of spatial structure was detected within the megafaunal assemblage, whereby patches with minimum radius between 123 and 163 m were nested within patches up to 400-m radius. The approach described in this paper offers ways forward to address how variation of megafaunal spatial structure affects macrofaunal assemblage structure and to discuss the application of remote imaging to map and predict the conservation value of subtidal soft sediments.

The standard method for collecting information on both the abundance and distribution of surface-dwelling megafauna, and biotic sediment-features associated with burrowing megafauna has been direct observation and counting by divers. However, remote observations allow information comparable to diver observations to be applied to investigations at greater depths and over wider spatial extents than divers may achieve. The present paper compares abundance estimates of megafaunal biotic sediment-features obtained from diver and remotely operated vehicle-mapping techniques. Results show strong agreement between estimates of total-feature and conspicuous- feature abundance, providing assurance that remote observation techniques are not subject to systematic errors in estimation of feature abundance. The ability to detect the smallest features appeared to differ between observation techniques, but this was an artefact caused by measurement of features rather than feature detection. A laser diode array attached to the camera to quantify image scale increased the amount of quantitative data that may be extracted from remote images.

Patients with massive and submassive pulmonary embolism (PE) require rapid identification, triage and consideration for reperfusion therapy. The purpose of this analysis was to evaluate a pilot study using the ST elevation myocardial infarction (STEMI) team and a dedicated PE protocol for treatment

Species body size spectra have been constructed for macrofauna assemblages from four sites with contrasting sediment granulometry and heterogeneity in and around Plymouth Sound. The number of species and species turnover (β diversity) were higher on coarse sediment. While the fauna were distinct between sites, the median geometric size-class was conservative (class 14; 0.153–0.305 mg dry blotted weight). Only one site had significantly lower heterogeneity within the species size spectrum, yet this was the most heterogeneous sediment. As such, we were unable to reject the null hypothesis that species body size distribution patterns are conservative despite differences in sediment granulometry and heterogeneity.

The spatial scale of local patterns in the fauna of two contrasting shallow water sediment assemblages has been investigated using hierarchical sampling. Replicate samples were taken at separations of 50 cm, 5 m, 50 m and 500 m. No significant differences between samples could be detected on any of these scales in a fine sand assemblage. However, in a heavily bioturbated sandy mud, samples separated by more than 50 m were significantly different from each other. This separation was largely a result of changes in the pattern of dominance among the most abundant species, particularly annelids. In a complimentary set of analyses, animals were regrouped either by higher taxa or by body size. The numerically important annelids and crustaceans showed a pattern of spatial similarity close to the full data set, but that shown by molluscs was clearly distinct. Large bodied animals were also independent of the main pattern while smaller species conformed to it. In the case of the latter, separation of sites at the 50 m scale could be related to patterns of species richness as well as dominance.

In most subtidal soft-sediment faunal assemblages there is a trough in the species size distribution separating the macrofauna and meiofauna. To examine the hypothesis that this may be maintained by the avoidance of competition between macrofaunal adults and settling larvae, samples were taken from around Svalbard, an area where most macrofaunal species have either lecithotrophic or direct development. At three contrasting sites, bimodality of the species size spectrum was conserved. However, it is proposed that the adult-larval interaction hypothesis should not be rejected as low endemism in the fauna of the study area suggests its species size spectrum probably reflects evolutionary processes outside rather than within the Arctic.

Samples of the macrobenthic fauna of soft sediments were collected from around Svalbard during the 1991 Arctic EPOS cruise of RVPolarstern. Although faunal variability could be related to sediment granulometry and depth, all stations to the south and east of the Archipelago lay within the broadly defined central Barents Sea community. In this community,α-diversity was variable and sampled between 77 and 337 m showed no clear relationship to depth. Diversity in the area close to the polar front was notably high, rarefaction predicting that 43±5.5 species might occur in a sample of 201 individuals.k-Dominance plots suggested that muddy sand communities around Svalbard were no less diverse than similar assemblages in the North Sea.

The research presented in this dissertation presents a methodology to experimentally predict and simulate the mechanical behavior of polymers under high strain rate deformation. Specifically, the interplay between the effects of temperature and strain rate on polymer behavior is examined and then used as a tool to help recreate the high rate mechanical response of several different polymers: ranging from rubbers to amorphous polymers to composites. Multiple literature reviews are conducted and presented in this thesis, e.g. experimental mechanics test methods, high rate behavior, time-temperature equivalence, constitutive modeling, and temperature measurement methods. In accordance with mechanical theory, an experimental and analytical protocol in rate- and temperature- dependence was applied to a range of PVC materials ranging in plasticizer contents. Further to this, these PVC materials were modeled with a rubbery model describing the network stress seen in polymer behavior, and an amorphous polymer model to describe PVC low to high rate responses to deformation. This modeling develops insights in the adiabatic nature of high rate response. Time-temperature equivalence, and the temperature rise during adiabatic deformation, are studied and exploited in order to implement a proposed experimental method which simulates the high rate deformation of polymeric materials. The development of an experimental methodology to simulate and predict high rate behavior is presented, applied, and expanded to a range of materials: amorphous polymers (e.g. PVC 20wt% plasticizer, PMMA, PC) and composites (e.g. polymer bonded explosive simulant). The work also presents and highlights the fact that micro to nano-scale imaging may be used in parallel with the simulation method in order to better understand high rate behavior. Furthermore, in result of the studies conducted in this body of work, several novel techniques were developed, or improved upon, and applied to the current research (e.g. additions to time-temperature equivalence, temperature measurement methods at high, moderate, and low strain rates, and a method for measuring the high rate behavior of soft materials).

Experimental manipulations of food supply were performed on soft sediment cores from two European estuaries, the Westerscheldt and the Gironde, with a view to determining benthic macrofaunal community response. Over a period of twenty weeks in a laboratory mesocosm system, both communities showed losses in terms of numbers of individuals and small, but non-significant, losses in terms of numbers of species. Whereas no effect of the different types of foods or the dose levels at which they were supplied was detected for the Westerscheldt benthic community, that of the Gironde showed some significant response. This was largely attributed to the differential mortality of spionid polychaetes across the dose levels used, with the highest dose, equivalent to 200 g C m−2 yr−1, only just maintaining their initial population densities. The results are discussed in terms of the importance of lateral advection of food particles at the benthic boundary layer and the general insufficiency of many estimates of carbon input to shallow benthic systems.

Combined hydroacoustic, video and direct examination by scuba-diving of the underwater meadows of Hornsund, a flagship biodiversity site in Svalbard, revealed 17 species of macroalgae with a biomass, dominated by Laminariales, of as much as 3 kg m -2 . The biomass dominants were Laminaria digitata and Saccharina latissima , which were most abundant at depths of between 5 and 10 m. The species data presented are the first records for the fjord and provide a starting point for new research and a baseline for future assessments of climate-induced changes. Keywords: Macroalgae; Hornsund; Arctic fjord; West Spitsbergen; laminariales (Published: 18 July 2012) Citation: Polar Research 2012, 31 , 18900, http://dx.doi.org/10.3402/polar.v31i0.18900

The pattern of occurrence and recent changes in the distribution of macrobenthic organisms in fjordic and coastal (nearshore) Arctic waters are reviewed and future changes are hypothesized. The biodiversity patterns ob- served are demonstrated to be contextual, depending on the specific region of the Arctic or habitat type. Two major areas of biotic advection are indicated (the North Atlantic Current along Scandinavia to Svalbard and the Bering Strait area) where larvae and adult animals are transported from the species-rich sub-Arctic areas to species-poor Arctic areas. In those Arctic areas, increased temperature associ- ated with increased advection in recent decades brings more boreal-subarctic species, increasing the local biodiversity when local cold-water species may be suppressed. Two other large coastal areas are little influenced by advected waters; the Siberian shores and the coasts of the Canadian Archipelago. There, local Arctic fauna are exposed to increasing ocean temperature, decreasing salinity and a reduction in ice cover with unpredictable effect for biodiversity. One the one hand, benthic species in Arctic fjords are exposed to increased siltation (from glacial meltwater) and salinity decreases, which together may lead to habitat homogenization and a subsequent decrease in biodiversity. On the other hand, the innermost basins of Arctic fjords are able to maintain pockets of very cold, dense, saline water and thus may act as refugia for cold- water species.

As part of a programme to re-assess the existence of latitudinal gradients in the diversity of the macrobenthic infauna of soft sediments, samples were taken from Sassenfjord, Spitzbergen. Abundancebiomass curves showed the shallowest sites to be moderately disturbed, possibly as a result of glacial run-off from the Gipselva. These clearly differed from a site at 123 m which appeared to be in an undisturbed state. A comparison of the diversity profile of the latter site (78 °N) with those of physically similar sites in the North Sea (55 °N) and off the coast of Java (7 °S), sampled by identical methods, shows no real difference in diversity.

Marine organisms that produce calcium carbonate structures are predicted to be most vulnerable to a decline in oceanic pH (ocean acidification) based on the understanding that calcification rates will decrease as a result of changes in the seawater carbonate chemistry thereby reducing carbonate ion concentration (and associated saturation states). Coastal seas are critical components of the global carbon cycle yet little research has been conducted on acidification impacts on coastal benthic organisms. Here, a critical appraisal of calcification in six benthic species showed, contrary to popular predictions, calcification can increase, and not decrease, in acidified seawater. Measuring the changes in calcium in isolated calcium carbonate structure as well as structures from live animals exposed to acidified seawater allowed a comparison between a species' ability to calcify and the dissolution affects across decreasing levels of pH. Calcium carbonate production is dependant on the ability to increase calcification thus counteracting an increase in dissolution. Comparison with paleoecological studies of past high carbon dioxide (CO2) events presents a similar picture. This conclusion implies that calcification may not be the critical process impacted by ocean acidification; particularly as all species investigated displayed physiological trade offs including reduced metabolism, health, and behavioural responses, in association with this calcification upregulation, which possess as great a threat to survival as an inability to calcify.

Species abundance data for benthic communities, collected during 1971–1988 off Northumberland on the north-east coast of England (western North Sea) and the Skagerrak (eastern North Sea), and pelagic data collected in corresponding areas during 1958–1988 by the Continuous Plankton Recorder (CPR) survey have been subjected tomulti-dimensional scaling ordination. Changes in community structure at the two benthic stations show a high degree of similarity, characterised by a transition in the late 70s. Similarly, there is a less marked transition between the 70s and 80s in pelagic community structure from the eastern North Sea but pelagic data from the western North Sea shows no discernible patterns. Benthic community biomass data, available only for the Skagerrak station, enabled abundance/biomass comparison curves to be constructed which demonstrated a change from un-disturbed communities in the early and mid 70s to moderately disturbed communities in the late 70s and 80s. North Sea macrofaunal abundance, and, in the Skagerrak, macrofaunal biomass appear to co-vary with phytoplankton colour and total zooplankton abundance, although there are insufficient data for statistical testing. A number of factors including eutrophication and/or pollution may be responsible for these changes in community structure.

At a large North Sea pockmark, with active methane seeps, surface sediments were found to have higher insoluble sulphide concentrations than sedlments from the surrounding area. The fauna of the pockmark was characterized by 2 species which have not pi-evlously been reported from the Fladen Ground in the northern North Sea. These species were a b~valve, Thyasira sarsi (which is known to contain endosymbiotic sulphur-oxidising bacteria) and a mouthless and gutless nematode, Astomonerna sp., which also contains endosymbiotic bacteria The nematode was the dominant meiofauna species in the pockmark sediments. Both macro-lnfauna and total nematodes were in low abundance in samples taken from the base of the pockmark. Sediment samples from the pockmark contained numerous otoliths, implying that substantial winnowing of the sediment had taken place. This was supported by studies on the sulphide concentrations in the sediment which showed multiple layering of the sediments on the sides of the pockmark, suggesting displacement. The carbon isotope compositions (6I3c) of the tissues of benthic animals from in and around the pockmark were generally in the range -16 to -2O%, indicating that little methane-derived carbon was contributing to their nutrition. T sarsi had the most 13c-depleted tissues, -31.4 to -35.1 L, confirming the nutritional dependence of this species on chemoautotrophic bacteria that utilize reduced sulphur.

Several recent studies have shown the potential value of chloroform-soluble fluorescent age pigments (FAPs) in determining the age of marine invertebrates with no permanent hard parts. The primary assumption in estimating age from FAPs is that there is a linear (or at least monotonie) increase in FAP content with time. We have tested this assumption with the trochid gastropod Monodonta lineata , a species whose age can be established unequivocally from shell growth checks. Samples of 10 age classes (1.5–10.5 yr) were obtained and FAPs extracted from lyophilised cerebral ganglia and digestive gland. The fluorescence emission spectra were similar to those reported for other organisms, though the wavelength of maximum intensity varied with tissue, sex and age. Cerebral ganglia often showed two major emission peaks, digestive gland only one. Thin-layer chromatography indicated that at least three fluorescent compounds were present in the extracts. Digestive gland total FAP content did not vary for the first 5 yr of growth, but then trebled during the next 5 yr. The tissue concentration of FAP showed no statistically significant trend. Cerebral ganglia total FAP content increased during the first 5 yr then remained constant for the next 3 yr before declining. There was a steady decline in the concentration of cerebral ganglion FAP throughout life. These patterns indicate a complex relationship between FAP content and calendar age, and indicate that (at least in Monodonta ) FAPs have little practical value for determining age.

Long-term research in the western English Channel, undertaken by the marine laboratories in Plymouth, is described and details of survey methods, sites, and time series given in this chapter. Major findings are summarized and their limitations outlined. Current research, with recent reestablishment and expansion of many sampling programmes, is presented, and possible future approaches are indicated. These unique long-term data sets provide an environmental baseline for predicting complex ecological responses to local, regional, and global environmental change. Between 1888 and the present, investigations have been carried out into the physical, chemical, and biological components (ranging from plankton and fish to benthic and intertidal assemblages) of the western English Channel ecosystem. The Marine Biological Association of the United Kingdom has performed the main body of these observations. More recent contributions come from the Continuous Plankton Recorder Survey, now the Sir Alister Hardy Foundation for Ocean Science, dating from 1957; the Institute for Marine Environmental Research, from 1974 to 1987; and the Plymouth Marine Laboratory, which was formed by amalgamation of the Institute for Marine Environmental Research and part of the Marine Biological Association, from 1988. Together, these contributions constitute a unique data series-one of the longest and most comprehensive samplings of environmental and marine biological variables in the world. Since the termination of many of these time series in 1987-1988 during a reorganisation of UK marine research, there has been a resurgence of interest in long-term environmental change. Many programmes have been restarted and expanded with support from several agencies. The observations span significant periods of warming (1921-1961; 1985-present) and cooling (1962-1980). During these periods of change, the abundance of key species underwent dramatic shifts. The first period of warming saw changes in zooplankton, pelagic fish, and larval fish, including the collapse of an important herring fishery. During later periods of change, shifts in species abundances have been reflected in other assemblages, such as the intertidal zone and the benthic fauna. Many of these changes appear to be related to climate, manifested as temperature changes, acting directly or indirectly. The hypothesis that climate is a forcing factor is widely supported today and has been reinforced by recent studies that show responses of marine organisms to climatic attributes such as the strength of the North Atlantic Oscillation. The long-term data also yield important insights into the effects of anthropogenic disturbances such as fisheries exploitation and pollution. Comparison of demersal fish hauls over time highlights fisheries effects not only on commercially important species but also on the entire demersal community. The effects of acute ("Torrey Canyon" oil spill) and chronic (tributyltin [TBT] antifoulants) pollution are clearly seen in the intertidal records. Significant advances in diverse scientific disciplines have been generated from research undertaken alongside the long-term data series. Many concepts in marine biological textbooks have originated in part from this work (e.g. the seasonal cycle of plankton, the cycling of nutrients, the pelagic food web trophic interactions, and the influence of hydrography on pelagic communities). Associated projects currently range from studies of marine viruses and bacterial ecology to zooplankton feeding dynamics and validation of ocean colour satellite sensors. Recent advances in technology mean these long-term programmes are more valuable than ever before. New technology collects data on finer temporal and spatial scales and can be used to capture processes that operate on multiple scales and help determine their influence in the marine environment. The MBA has been in the forefront of environmental modelling of shelf seas since the early 1970s. Future directions being pursued include the continued development of coupled physical-ecosystem models using western English Channel time-series data. These models will include both the recent high-resolution data and the long-term time-series information to predict effects of future climate change scenarios. It would be beneficial to provide more spatial and high-resolution temporal context to these data, which are fundamental for capturing processes that operate at multiple scales and understanding how they operate within the marine environment. This is being achieved through employment of technologies such as satellite-derived information and advanced telemetry instruments that provide real-time in situ profile data from the water column.

Long-term research in the western English Channel, undertaken by the marine laboratories in Plymouth, is described and details of survey methods, sites, and time series given in this chapter. Major findings are summarized and their limitations outlined. Current research, with recent reestablishment and expansion of many sampling programmes, is presented, and possible future approaches are indicated. These unique long-term data sets provide an environmental baseline,for predicting complex ecological responses to local, regional, and global environmental change. Between 1888 and the present, investigations have been carried out into the physical, chemical, and biological components (ranging from plankton and fish to benthic and intertidal assemblages) of the western English Channel ecosystem. The Marine Biological Association of the United Kingdom has performed the main body of these observations. More recent contributions come from the Continuous Plankton Recorder Survey, now the Sir Alister Hardy Foundation for Ocean Science, dating from 1957; the Institute for Marine Environmental Research, from 1974 to 1987; and the Plymouth Marine Laboratory, which was formed by amalgamation of the Institute for Marine Environmental Research and part of the Marine Biological Association,,from 1988. Together, these contributions constitute a unique data series-one of the longest and most comprehensive samplings of enviromnental and marine biological variables in the world. Since the termination of many of these time series in 1987-1988 during a reorganisation of UK marine research, there has been a resurgence of interest in long-term environmental change. Many programmes have been restarted and expanded with support from several agencies. The observations span significant periods of warming (1921-1961; 1985-present) and cooling (1962-1980). During these periods of change, the abundance of key species underwent dramatic shifts. The first period of warming saw changes in zooplankton, pelagic fish, and larval fish, including the collapse of an important herring fishery. During later periods of change, shifts in species abundances have been reflected in other assemblages, such as the intertidal zone and the benthic fauna. Many of these changes appear to be related to climate, manifested as temperature changes, acting directly or indirectly. The hypothesis that climate is a forcing factor is widely supported today and has been reinforced by recent studies that show, responses of marine organisms to climatic attributes such as the strength of the North Atlantic Oscillation. The long-term data also yield important insights into the effects of anthropogenic disturbances such as fisheries exploitation and pollution. Comparison of demersal fish hauls over time highlights fisheries effects not only on commercially important species but also on the entire demersal community. The effects of acute ("Torrey Canyon" oil spill) and chronic (tributyltin [TBT] antifoulants) pollution are clearly seen in the intertidal records. Significant advances in diverse scientific disciplines have been generated from research undertaken alongside the long-term data series. Many concepts in marine biological textbooks have originated in part from this work (e.g. the seasonal cycle of plankton, the cycling of nutrients, the pelagic food web trophic interactions, and the influence of hydrography on pelagic communities). Associated projects currently range.from studies of marine viruses and bacterial ecology to zooplankton feeding dynamics and validation of ocean colour satellite sensors. Recent advances in technology mean these long-term programmes are more valuable than ever before. New technology collects data on finer temporal and spatial scales and can be used to capture processes that operate on multiple scales and hell) determine their influence in the marine environment. The MBA has been in the forefront of environmental modelling of sheaf seas since the early 1970s. Future directions being pursued include the continued development of coupled physical-ecosystem models using western English Channel time-series data. These models will include both the recent high-resolution data and the long-term time-series information to predict effects of future climate change scenarios. It, would be beneficial to provide more spatial and high-resolution temporal context to these data, which are fundamental for capturing processes that operate at multiple scales and understanding hoiv they operate within the marine environment. This is being achieved through employment of technologies such as sateillite-derived information and advanced telemetry instruments that pro vide real-time in situ profile data from the water column.

Over 2 years, experiments were conducted to compare the effects of sediment disturbance by different bioturbating, macrofaunal organisms on the diversity and structure of the associated infaunal community. The four species investigated were the bivalves Nuculoma tenuis (Montagu, 1808) and Abra alba (Wood, 1802), the heart urchin Brissopsis lyrifera (Forbes, 1841), and the burrowing decapod Calocaris macandreae (Bell, 1846). These organisms were chosen to allow assessment of the effects of contrasting feeding activities and body sizes of the bioturbating species on the diversity of the macrobenthic communities. Bioturbation by the sub-surface deposit feeders N. tenuis and B. lyrifera promoted higher levels of α and β diversity in treatments exposed to intermediate levels of disturbance. Whilst no such ‘intermediate response’ was demonstrated for A. alba or C. macandreae, it was evident that changes in the associated fauna were influenced by the feeding type of the bioturbating organism responsible. It was also shown that different elements of the associated community responded differently to biotic disturbance. The results indicate that the variability in density and distribution of such bioturbators are important factors in structuring infaunal communities, and in setting and maintaining levels of diversity in apparently homogeneous areas.

Droplet-based microfluidic systems enable a variety of biomedical applications from point-of-care diagnostics with third world implications, to targeted therapeutics alongside medical ultrasound, to molecular screening and genetic testing. Though these systems maintain the key advantage of precise control of the size and composition of the droplet as compared to conventional methods of production, the low rates at which droplets are produced limits translation beyond the laboratory setting. As well, previous attempts to scale up shear-based microfluidic systems focused on increasing the volumetric throughput and formed large droplets, negating many practical applications of emulsions such as site-specific therapeutics. We present the operation of a parallel module with eight flow-focusing orifices in the dripping regime of droplet formation for the generation of uniform fine droplets at rates in the hundreds of kilohertz. Elevating the capillary number to access dripping, generation of monodisperse droplets of liquid perfluoropentane in the parallel module exceeded 3.69 × 10(5) droplets per second, or 1.33 × 10(9) droplets per hour, at a mean diameter of 9.8 μm. Our microfluidic method offers a novel means to amass uniform fine droplets in practical amounts, for instance, to satisfy clinical needs, with the potential for modification to form massive amounts of more complex droplets.

This article discusses the utility and limitations of urethroscopy and cystoscopy in both male and female cats. The special equipment and techniques necessary to adequately visualize the urethra and bladder of female cats are described in some detail. The emerging ability to visualize the male urethra is introduced. Photographs taken through the cystoscope are used to illustrate both normal anatomy and lesions likely to be encountered with cats with lower urinary tract disease. Cystoscopy is an important diagnostic tool for an inclusionary and exclusionary diagnosis of interstitial cystitis (sterile idiopathic inflammation).

The human pulmonary microvasculature from the apical bronchopulmonary segment was studied by scanning electron microscopy using latex replicas. The latex replica was composed of a blend of vinyl chloride latexes using a plasticized vinyl chloride copolymer with a vinyl chloride copolymer. The polymerized latex produced a cast of the pulmonary arterial vascular tree, including the capillary patterns, which freely anastomose, thereby draining blood into pulmonary veinules and veins. The latex was injected via a gravity flow system modified from its earlier application in Guinea pig lungs. The apparently normal lungs from two recently deceased humans (dead for 5-6 hours and held in refrigeration) were perfused with heparinized Ringer's solution and subsequently injected with latex. The resulting latex casts of the capillaries revealed a three-dimensional network arranged in irregular vascular rings or ovals. This pattern was most conspicuous in deep and intermediate bronchopulmonary segmental areas. However, the subpleural capillaries produced casts that often terminated blindly, as observed with stereo SEm, suggesting that these vessels may tend to form thrombi more easily as compared with capillaries from other regions of the lung alveoli. The pulmonary arteriolar replicas contained indentations representing endothelial cell nuclei, and the capillary replicas projected oval evaginations that may represent discrete loci or capillary mural attenuations.

Seasonal changes in the rate of shell formation frequently affect the surface morphology of molluscan shells, with reductions in feeding activity and calcification rates at low temperatures producing winter rings that can be used for age determination. Such annuli are well-known in lamellibranchs and have greatly facilitated studies on their growth, longevity and other age-related processes (as reviewed by Wibur & Owen, 1964; Rhoads & Panella, 1970; Comfort, 1957, 1979). However, they occur less frequently in gastropods and many species that do show such checks are relatively short-lived, or else their growth ceases or becomes erratic on sexual maturity.