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Sharks are one of the most threatened groups of marine animals worldwide, mostly owing to overfishing and habitat degradation/loss. Although these cartilaginous fish have evolved to fill many ecological niches across a wide range of habitats, they have limited capability to rapidly adapt to human-induced changes in their environments. Contrary to global warming, ocean acidification was not considered as a direct climate-related threat to sharks. Here we show, for the first time, that an early ontogenetic acclimation process of a tropical shark (Chiloscyllium punctatum) to the projected scenarios of ocean acidification (ΔpH = 0.5) and warming (+4°C; 30°C) for 2100 elicited significant impairments on juvenile shark condition and survival. The mortality of shark embryos at the present-day thermal scenarios was 0% both at normocapnic and hypercapnic conditions. Yet routine metabolic rates (RMRs) were significantly affected by temperature, pH and embryonic stage. Immediately after hatching, the Fulton condition of juvenile bamboo sharks was significantly different in individuals that experienced future warming and hypercapnia; 30 days after hatching, survival rapidly declined in individuals experiencing both ocean warming and acidification (up to 44%). The RMR of juvenile sharks was also significantly affected by temperature and pH. The impact of low pH on ventilation rates was significant only under the higher thermal scenario. This study highlights the need of experimental-based risk assessments of sharks to climate change. In other words, it is critical to directly assess risk and vulnerability of sharks to ocean acidification and warming, and such effort can ultimately help managers and policy-makers to take proactive measures targeting most endangered species., (© 2014 The Author(s) Published by the Royal Society. All rights reserved.)

Onuphis farensis sp. nov. (Annelida, Polychaeta) is described, based on a population inhabiting intertidal sandbanks in the mesotidal coastal lagoon of Ria Formosa (Southern Portugal). It can be distinguished from all other known species within the genus by having bi- and tridentate pseudocompound hooks on the first 4 chaetigers, single filament branchiae from chaetiger 5, and subacicular hooks from chaetiger 9. The species was previously collected in the Bay of Cádiz and Isla Cristina (SW Spain), in a similar habitat to Ria Formosa, but referred to O. geophiliformis Moore, 1903. The taxonomic status of other Onuphis species recorded in the European waters is also discussed. On the whole, O. pancerii Claparède, 1868, described from the Gulf of Naples, has been treated as a junior synonym of O. eremita Audouin & Milne-Edwards, 1833, but taking the more restrictive definition of this species accepted today, should be considered as a valid Mediterranean species. Finally, O. opalina (Verrill, 1873) and O. rullieriana (Amoureux, 1977) may be synonymous, as both species are similar morphologically, occur at similar depths, and have partially overlapping geographical distributions. The different diagnostic characters utilised for the new species are analysed, with the number of chaetigers with postchaetal lobes determined to be a poor taxonomic character for the genus Onuphis, proving to be size-related. A synoptic table with all worldwide species of the genus Onuphis is provided, together with a dichotomic key for the species hitherto recorded in the European and nearby waters.

Both climate change and biological invasions are among the most serious global environmental threats. Yet mechanisms underlying these eventual interactions remain unclear. The aim of this study was to undertake a comprehensive examination of the physiological and biochemical responses of native (Ruditapes decussatus) and alien-invasive (Ruditapes philippinarum) clams to environmental warming. We evaluated thermal tolerance limits (CTMax), routine metabolic rates (RMRs) and respective thermal sensitivity (Q10 values), critical oxygen partial pressure (Pcrit), heat shock response (HSP70/HSC70 levels), lipid peroxidation (MDA build-up) and antioxidant enzyme [glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD)] activities. Contrary to most studies that show that invasive species have a higher thermal tolerance than native congeners, here we revealed that the alien-invasive and native species had similar CTMax values. However, warming had a stronger effect on metabolism and oxidative status of the native R. decussatus, as indicated by the higher RMRs and HSP70/HSC70 and MDA levels, as well as GST, CAT and SOD activities. Moreover, we argue that the alien-invasive clams, instead of up-regulating energetically expensive cellular responses, have evolved a less demanding strategy to cope with short-term environmental (oxidative) stress-pervasive valve closure. Although efficient during stressful short-term periods to ensure isolation and guarantee longer survival, such adaptive behavioural strategy entails metabolic arrest (and the enhancement of anaerobic pathways), which to some extent will not be advantageous under the chronically warming conditions predicted in the future., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions between them. Light is considered as a major factor affecting coral skeleton morphology, due to their symbiotic relation with photosynthetic zooxanthellae. Nonetheless, most studies addressing the importance of light on coral morphological plasticity have focused on photosynthetically active radiation (PAR) intensity, with the effect of light spectra remaining largely unknown. The present study evaluated how different light spectra affect the skeleton macro- and microstructures in two coral species (Acropora formosa sensu Veron (2000) and Stylophora pistillata) maintained under controlled laboratory conditions. We tested the effect of three light treatments with the same PAR but with a distinct spectral emission: 1) T5 fluorescent lamps with blue emission; 2) Light Emitting Diodes (LED) with predominantly blue emission; and 3) Light Emitting Plasma (LEP) with full spectra emission. To exclude potential bias generated by genetic variability, the experiment was performed with clonal fragments for both species. After 6 months of experiment, it was possible to detect in coral fragments of both species exposed to different light spectra significant differences in morphometry (e.g., distance among corallites, corallite diameter, and theca thickness), as well as in the organization of their skeleton microstructure. The variability found in the skeleton macro- and microstructures of clonal organisms points to the potential pitfalls associated with the exclusive use of morphometry on coral taxonomy. Moreover, the identification of a single factor influencing the morphology of coral skeletons is relevant for coral aquaculture and can allow the optimization of reef restoration efforts.

The jumbo squid, Dosidicus gigas, can survive extended forays into the oxygen minimum zone (OMZ) of the Eastern Pacific Ocean. Previous studies have demonstrated reduced oxygen consumption and a limited anaerobic contribution to ATP production, suggesting the capacity for substantial metabolic suppression during hypoxic exposure. Here, we provide a more complete description of energy metabolism and explore the expression of proteins indicative of transcriptional and translational arrest that may contribute to metabolic suppression. We demonstrate a suppression of total ATP demand under hypoxic conditions (1% oxygen, PO2 =0.8 kPa) in both juveniles (52%) and adults (35%) of the jumbo squid. Oxygen consumption rates are reduced to 20% under hypoxia relative to air-saturated controls. Concentrations of arginine phosphate (Arg-P) and ATP declined initially, reaching a new steady state (~30% of controls) after the first hour of hypoxic exposure. Octopine began accumulating after the first hour of hypoxic exposure, once Arg-P breakdown resulted in sufficient free arginine for substrate. Octopine reached levels near 30 mmol g(-1) after 3.4 h of hypoxic exposure. Succinate did increase through hypoxia but contributed minimally to total ATP production. Glycogenolysis in mantle muscle presumably serves to maintain muscle functionality and balance energetics during hypoxia. We provide evidence that post-translational modifications on histone proteins and translation factors serve as a primary means of energy conservation and that select components of the stress response are altered in hypoxic squids. Reduced ATP consumption under hypoxia serves to maintain ATP levels, prolong fuel store use and minimize the accumulation of acidic intermediates of anaerobic ATP-generating pathways during prolonged diel forays into the OMZ. Metabolic suppression likely limits active, daytime foraging at depth in the core of the OMZ, but confers an energetic advantage over competitors that must remain in warm, oxygenated surface waters. Moreover, the capacity for metabolic suppression provides habitat flexibility as OMZs expand as a result of climate change., (© 2014. Published by The Company of Biologists Ltd.)

The intertidal zone is an extremely variable habitat, imposing stressful conditions on its inhabiting communities. Tolerance towards extremes of temperature, salinity and pH are crucial in these habitats. Despite the vast literature on stress tolerance, few studies have focused on the synergistic effects of several variables on thermal tolerance and HSP70 (heat shock protein 70 kDa) levels. In this work, the crabs were exposed to three experimental conditions 1) thermal ramp at standard pH (8) and saline conditions (35‰) (named T), 2) thermal ramp at standard pH (8) and hyposaline conditions (15‰) (named T plus HypoS), and 3) thermal ramp at lower pH (7) and standard saline conditions (35‰) (named T plus A). Two physiological parameters (Critical Thermal Maximum - CTMax, and osmolality) and a stress biomarker (HSP70) were chosen for this analysis. These parameters were measured in all of the aforementioned conditions. CTMax for each set of conditions was reached by exposing the organisms to a rate of temperature increase of 1 °C h(-1) until loss of equilibrium. Haemolymph samples were taken every 2 °C to quantify HSP70 and osmolality. Results showed that CTMax did not differ between crabs solely exposed to T stress and crabs exposed to T plus HypoS stress. However, HSP70 production was impaired in T plus HypoS stress. When crabs were exposed to T plus A stress, they showed a significantly higher CTMax, suggesting that short-term exposure to acidified conditions may alter the thermal window of this species. Nevertheless, in T plus A conditions HSP70 production was impaired as well. Regarding osmolality it decreased according to temperature increase in all tested stress conditions. This study showed that the heat stress response is altered by the synergistic effect of variables. Physiological end-points (i.e. CTMax) may vary and the expression of stress proteins such as HSP70 may be impaired., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The chemical diversity associated with marine natural products (MNP) is unanimously acknowledged as the "blue gold" in the urgent quest for new drugs. Consequently, a significant increase in the discovery of MNP published in the literature has been observed in the past decades, particularly from marine invertebrates. However, it remains unclear whether target metabolites originate from the marine invertebrates themselves or from their microbial symbionts. This issue underlines critical challenges associated with the lack of biomass required to supply the early stages of the drug discovery pipeline. The present review discusses potential solutions for such challenges, with particular emphasis on innovative approaches to culture invertebrate holobionts (microorganism-invertebrate assemblages) through in toto aquaculture, together with methods for the discovery and initial production of bioactive compounds from these microbial symbionts.

Early life stages of many marine organisms are being challenged by rising seawater temperature and CO₂ concentrations, but their physiological responses to these environmental changes still remain unclear. In the present study, we show that future predictions of ocean warming (+4°C) and acidification (ΔpH=0.5 units) may compromise the development of early life stages of a highly commercial teleost fish, Solea senegalensis. Exposure to future conditions caused a decline in hatching success and larval survival. Growth, metabolic rates and thermal tolerance increased with temperature but decreased under acidified conditions. Hypercapnia and warming amplified the incidence of deformities by 31.5% (including severe deformities such as lordosis, scoliosis and kyphosis), while promoting the occurrence of oversized otoliths (109.3% increase). Smaller larvae with greater skeletal deformities and larger otoliths may face major ecophysiological challenges, which might potentiate substantial declines in adult fish populations, putting in jeopardy the species' fitness under a changing ocean., (© 2014. Published by The Company of Biologists Ltd.)

Little is known about the capacity of early life stages to undergo hypercapnic and thermal acclimation under the future scenarios of ocean acidification and warming. Here, we investigated a comprehensive set of biological responses to these climate change-related variables (2°C above winter and summer average spawning temperatures and ΔpH=0.5 units) during the early ontogeny of the squid Loligo vulgaris. Embryo survival rates ranged from 92% to 96% under present-day temperature (13-17°C) and pH (8.0) scenarios. Yet, ocean acidification (pH 7.5) and summer warming (19°C) led to a significant drop in the survival rates of summer embryos (47%, P<0.05). The embryonic period was shortened by increasing temperature in both pH treatments (P<0.05). Embryo growth rates increased significantly with temperature under present-day scenarios, but there was a significant trend reversal under future summer warming conditions (P<0.05). Besides pronounced premature hatching, a higher percentage of abnormalities was found in summer embryos exposed to future warming and lower pH (P<0.05). Under the hypercapnic scenario, oxygen consumption rates decreased significantly in late embryos and newly hatched paralarvae, especially in the summer period (P<0.05). Concomitantly, there was a significant enhancement of the heat shock response (HSP70/HSC70) with warming in both pH treatments and developmental stages. Upper thermal tolerance limits were positively influenced by acclimation temperature, and such thresholds were significantly higher in late embryos than in hatchlings under present-day conditions (P<0.05). In contrast, the upper thermal tolerance limits under hypercapnia were higher in hatchlings than in embryos. Thus, we show that the stressful abiotic conditions inside the embryo's capsules will be exacerbated under near-future ocean acidification and summer warming scenarios. The occurrence of prolonged embryogenesis along with lowered thermal tolerance limits under such conditions is expected to negatively affect the survival success of squid early life stages during the summer spawning period, but not winter spawning.

Marine phycotoxins derived from harmful algal blooms are known to be associated with mass mortalities in the higher trophic levels of marine food webs. Bivalve mollusks and planktivorous fish are the most studied vectors of marine phycotoxins. However, field surveys recently showed that cephalopod mollusks also constitute potential vectors of toxins. Thus, here we determine, for the first time, the time course of accumulation and depuration of paralytic shellfish toxins (PSTs) in the common octopus (Octopus vulgaris). Concomitantly, the underlying kinetics of toxin transfer between tissue compartments was also calculated. Naturally contaminated clams were used to orally expose the octopus to PSTs during 6 days. Afterwards, octopus specimens were fed with non-contaminated shellfish during 10 days of depuration period. Toxins reached the highest concentrations in the digestive gland surpassing the levels in the kidney by three orders of magnitude. PSTs were not detected in any other tissue analyzed. Net accumulation efficiencies of 42% for GTX5, 36% for dcSTX and 23% for C1+2 were calculated for the digestive gland. These compounds were the most abundant toxins in both digestive gland and the contaminated shellfish diet. The small differences in relative abundance of each toxin observed between the prey and the cephalopod predator indicates low conversion rates of these toxins. The depuration period was better described using an exponential decay model comprising a single compartment - the entire viscera. It is worth noting that since octopuses' excretion and depuration rates are low, the digestive gland is able to accumulate very high toxin concentrations for long periods of time. Therefore, the present study clearly shows that O. vulgaris is a high-potential vector of PSTs during and even after the occurrence of these toxic algal blooms., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The ability to understand and predict the effects of ocean warming (under realistic scenarios) on marine biota is of paramount importance, especially at the most vulnerable early life stages. Here we investigated the impact of predicted environmental warming (+3 °C) on the development, metabolism, heat shock response and antioxidant defense mechanisms of the early stages of the common octopus, Octopus vulgaris. As expected, warming shortened embryonic developmental time by 13 days, from 38 days at 18 °C to 25 days at 21 °C. Concomitantly, survival decreased significantly (~29.9 %). Size at hatching varied inversely with temperature, and the percentage of smaller premature paralarvae increased drastically, from 0 % at 18 °C to 17.8 % at 21 °C. The metabolic costs of the transition from an encapsulated embryo to a free planktonic form increased significantly with warming, and HSP70 concentrations and glutathione S-transferase activity levels were significantly magnified from late embryonic to paralarval stages. Yet, despite the presence of effective antioxidant defense mechanisms, ocean warming led to an augmentation of malondialdehyde levels (an indicative of enhanced ROS action), a process considered to be one of the most frequent cellular injury mechanisms. Thus, the present study provides clues about how the magnitude and rate of ocean warming will challenge the buffering capacities of octopus embryos and hatchlings' physiology. The prediction and understanding of the biochemical and physiological responses to warmer temperatures (under realistic scenarios) is crucial for the management of highly commercial and ecologically important species, such as O. vulgaris.

The combined effects of future ocean acidification and global warming on the hypoxia thresholds of marine biota are, to date, poorly known. Here, we show that the future warming and acidification scenario led to shorter embryonic periods, lower survival rates and the enhancement of premature hatching in the cuttlefish Sepia officinalis. Routine metabolic rates increased during the embryonic period, but environmental hypercapnia significantly depressed pre-hatchling's energy expenditures rates (independently of temperature). During embryogenesis, there was also a significant rise in the carbon dioxide partial pressure in the perivitelline fluid (PVF), bicarbonate levels, as well as a drop in pH and oxygen partial pressure (pO₂). The critical partial pressure (i.e. hypoxic threshold) of the pre-hatchlings was significantly higher than the PVF oxygen partial pressure at the warmer and hypercapnic condition. Thus, the record of oxygen tensions below critical pO₂ in such climate scenario indicates that the already harsh conditions inside the egg capsules are expected to be magnified in the years to come, especially in populations at the border of their thermal envelope. Such a scenario promotes untimely hatching and smaller post-hatching body sizes, thus challenging the survival and fitness of early life stages.

The Humboldt (jumbo) squid, Dosidicus gigas, is a part-time resident of the permanent oxygen minimum zone (OMZ) in the Eastern Tropical Pacific and, thereby, it encounters oxygen levels below its critical oxygen partial pressure. To better understand the ventilatory mechanisms that accompany the process of metabolic suppression in these top oceanic predators, we exposed juvenile D. gigas to the oxygen levels found in the OMZ (1% O(2), 1 kPa, 10 °C) and measured metabolic rate, activity cycling patterns, swimming mode, escape jet (burst) frequency, mantle contraction frequency and strength, stroke volume and oxygen extraction efficiency. In normoxia, metabolic rate varied between 14 and 29 μmol O(2) g(-1) wet mass h(-1), depending on the level of activity. The mantle contraction frequency and strength were linearly correlated and increased significantly with activity level. Additionally, an increase in stroke volume and ventilatory volume per minute was observed, followed by a mantle hyperinflation process during high activity periods. Squid metabolic rate dropped more than 75% during exposure to hypoxia. Maximum metabolic rate was not achieved under such conditions and the metabolic scope was significantly decreased. Hypoxia changed the relationship between mantle contraction strength and frequency from linear to polynomial with increasing activity, indicating that, under hypoxic conditions, the jumbo squid primarily increases the strength of mantle contraction and does not regulate its frequency. Under hypoxia, jumbo squid also showed a larger inflation period (reduced contraction frequency) and decreased relaxed mantle diameter (shortened diffusion pathway), which optimize oxygen extraction efficiency (up to 82%/34%, without/with consideration of 60% potential skin respiration). Additionally, they breathe 'deeply', with more powerful contractions and enhanced stroke volume. This deep-breathing behavior allows them to display a stable ventilatory volume per minute, and explains the maintenance of the squid's cycling activity under such O(2) conditions. During hypoxia, the respiratory cycles were shorter in length but increased in frequency. This was accompanied by an increase in the number of escape jets during active periods and a faster switch between swimming modes. In late hypoxia (onset ~170 ± 10 min), all the ventilatory processes were significantly reduced and followed by a lethargic state, a behavior that seems closely associated with the process of metabolic suppression and enables the squid to extend its residence time in the OMZ.

The objectives of the present work were to investigate the temporal variation in the fatty acid (FA) composition of the octocoral Veretillum cynomorium, examine the effects of reproduction and environmental factors on FA variation, and establish a chemotaxonomic identification for this species. Mean oocyte size-frequency distributions showed that the majority of the oocytes had an intermediate size (Group II) before spawning (April and June). The late-vitellogenic oocytes (Group III) became absent in August and October and, during this post-spawning period, oocytes were primarily of small size (Group I). Most of the major FA, 16:0, 18:0, 20:4n-6, 20:5n-3, and the tetracosapolyenoic fatty acid (TPA), 24:6n-3, varied significantly throughout the year (p<0.01), with two peaks in August/October and February. The boost in early oogenesis, also associated with warmer temperatures, seemed to be responsible for the observed increase in FA content between June and August. The highest values of FA content were observed in February when intermediate oogenesis (Group II) was at its peak and there were considerable levels of available food in the environment. Also, the increase in food availability seemed to trigger the final stages of gametogenesis. The high quantity of 18:1n-7, odd-numbered and branched FAs, suggested the presence of a dynamic bacterial community in V. cynomorium, probably as an adaptive response to the lack of symbiotic microalgae. Although the presence of TPAs is the main feature distinguishing octocorals from other coral species, here we showed that there was no single FA clearly dominating the FA composition of V. cynomorium throughout the year. Instead, four main FAs share similar concentrations: 16:0, 20:4n-6, 20:5n-3 and 24:6n-3. The predominance of these four FAs combined with the higher amount of 24:6n-3 when compared to 24:5n-6 may serve as a chemotaxonomic feature to distinguish this octocoral species (or genus)., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: The knowledge about the capacity of organisms' early life stages to adapt to elevated temperatures is very limited but crucial to understand how marine biota will respond to global warming. Here we provide a comprehensive and integrated view of biological responses to future warming during the early ontogeny of a keystone invertebrate, the squid Loligo vulgaris., Methodology/principal Findings: Recently-spawned egg masses were collected and reared until hatching at present day and projected near future (+2°C) temperatures, to investigate the ability of early stages to undergo thermal acclimation, namely phenotypic altering of morphological, behavioural, biochemical and physiological features. Our findings showed that under the projected near-future warming, the abiotic conditions inside the eggs promoted metabolic suppression, which was followed by premature hatching. Concomitantly, the less developed newborns showed greater incidence of malformations. After hatching, the metabolic burst associated with the transition from an encapsulated embryo to a planktonic stage increased linearly with temperature. However, the greater exposure to environmental stress by the hatchlings seemed to be compensated by physiological mechanisms that reduce the negative effects on fitness. Heat shock proteins (HSP70/HSC70) and antioxidant enzymes activities constituted an integrated stress response to ocean warming in hatchlings (but not in embryos)., Conclusions/significance: The stressful abiotic conditions inside eggs are expected to be aggravated under the projected near-future ocean warming, with deleterious effects on embryo survival and growth. Greater feeding challenges and the lower thermal tolerance limits of the hatchlings are strictly connected to high metabolic demands associated with the planktonic life strategy. Yet, we found some evidence that, in the future, the early stages might support higher energy demands by adjusting some cellular functional properties to increase their thermal tolerance windows.

Tropical coastal ecosystems, such as mangroves, have a great ecological and socioeconomic importance for adjacent systems and local populations, but intensive environmental impact monitoring is still lacking, mainly in East Africa. This study evaluated the potential anthropogenic disturbance on Palaemon concinnus population structure and fitness. Palaemon concinnus populations from one peri-urban (domestic sewage impacted) and two pristine mangrove creeks were studied by sampling nearly 100 shrimps per location every 15 days for 12 months. The shrimps at the peri-urban location were larger, experienced longer reproductive periods, presented higher proportion of ovigerous females and better embryo quality when compared with shrimps inhabiting pristine locations. Physiological indices (RNA/DNA ratio) were similar between shrimps at pristine and peri-urban mangroves. However, a higher level of parasitation by a Bopyridae isopod, Pseudione elongata indicated some degree of stress on the host at the peri-urban mangrove, with potential effects on the host population dynamics., (Copyright © 2010. Published by Elsevier Ltd.)

We examined the oxygen consumption rates and activity levels of respiratory enzymes involved in the aerobic (citrate synthase [CS]) and anaerobic (octopine dehydrogenase [ODH]) metabolism of gonatid squids (Gonatus onyx and Gonatus pyrus) as a function of body size. The energy expenditure rates of gonatids (ranging from 2.51 to 8.79 micromol O(2) g(-1) h(-1) at 5 degrees C) are among the highest in Animalia when mass and temperature are taken into account. They reflect the low efficiency of jet propulsion and the animals' active life strategy as diel vertical migrants in the pelagic environment. Both metabolic rate and aerobic muscle potential (CS activity) were size independent across a size range of four orders of magnitude, which may be a result of their unusual body geometric allometry, extensive cutaneous respiration, and decreased energy-saving opportunities at larger sizes. Anaerobic metabolic potential (ODH activity) revealed a shift from positive scaling in juveniles to negative scaling among larger sizes. Juveniles are found in shallow water, where they are more susceptible to visually cued predators and require quicker size-specific escape responses and higher burst swimming capacities. Conversely, adults have reduced requirements for predator/prey interactions in the light-limited deep sea. Anaerobic metabolic scaling reflects an adaptive response to the changing physical and ecological demands across a depth gradient during this species's ontogenetic vertical migration.

Although the oceans cover 70% of the Earth's surface and the open ocean is by far the largest ecosystem on the planet, our knowledge regarding diversity patterns of pelagic fauna is very scarce. Here, we examine large-scale latitudinal and depth-related patterns of pelagic cephalopod richness in the Atlantic Ocean in relation to ambient thermal and productive energy availability. Diversity, across 17 biogeochemical regions in the open ocean, does not decline monotonically with latitude, but is positively correlated to the availability of oceanic resources. Mean net primary productivity (NPP), determined from ocean color satellite imagery, explains 37% of the variance in species richness. Outside the poles, the range in NPP explains over 40% of the variability. This suggests that cephalopods are well adapted to the spatial patchiness and seasonality of open-ocean resources. Pelagic richness is also correlated to sea surface temperature, with maximum richness occurring around 15 degrees C and decreasing with both colder and warmer temperatures. Both pelagic and benthos-associated diversities decline sharply from sublittoral and epipelagic regions to the slope and bathypelagic habitats and then steadily to abyssal depths. Thus, higher energy availability at shallow depths seems to promote diversification rates. This strong depth-related trend in diversity also emphasizes the greater influence of the sharp vertical thermal gradient than the smoother and more seasonal horizontal (latitudinal) one on marine diversity.