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Long-term biological time series that monitor ecosystems across the ocean’s full water column are extremely rare. As a result, classic paradigms are yet to be tested. One such paradigm is that variations in coastal upwelling drive changes in marine ecosystems throughout the water column. We examine this hypothesis by using data from three multidecadal time series spanning surface (0 m), midwater (200 to 1,000 m), and benthic (~4,000 m) habitats in the central California Current Upwelling System. Data include microscopic counts of surface plankton, video quantification of midwater animals, and imaging of benthic seafloor invertebrates. Taxon-specific plankton biomass and midwater and benthic animal densities were separately analyzed with principal component analysis. Within each community, the first mode of variability corresponds to most taxa increasing and decreasing over time, capturing seasonal surface blooms and lower-frequency midwater and benthic variability. When compared to local wind-driven upwelling variability, each community correlates to changes in upwelling damped over distinct timescales. This suggests that periods of high upwelling favor increase in organism biomass or density from the surface ocean through the midwater down to the abyssal seafloor. These connections most likely occur directly via changes in primary production and vertical carbon flux, and to a lesser extent indirectly via other oceanic changes. The timescales over which species respond to upwelling are taxon-specific and are likely linked to the longevity of phytoplankton blooms (surface) and of animal life (midwater and benthos), which dictate how long upwelling-driven changes persist within each community.

Social recognition is the ability of individuals in a species to differentiate among conspecifics based on their identity or biologically meaningful demographic. Despite evidence that they have sophisticated brains, complex behavioural repertoires, and acute sensory processing, surprisingly little is known about mechanisms aiding social recognition in cephalopods. This class’s unique chemotactile sense by the ventral arm surfaces gathers considerable information used in predator–prey interactions. Does it also help mediate social interactions? This study utilised 366 h of focal animal observations to assess the likelihood of Hapalochlaena maculosa, a nocturnal species, to retreat after physically contacting conspecifics based on their sex, familiarity and mating history. Females retreated from both sexes equally, while males were more likely to retreat after contacting female conspecifics. Most conspicuously, males were significantly more likely to retreat after contacting females with which they had already mated. These findings provide the first evidence for chemotactile sex discrimination and mate recognition within cephalopods, and supplement previous observations that male H. maculosa do not appear to detect the sex of conspecifics from a distance. The decision to retreat from or stay with an individual based on their sex or mating history, only after physical contact, emphasises the importance of chemotactile behaviour in octopus sensory ecology and behaviour. Furthermore, male octopuses have limited spermatophore production, and the use of chemotactile social recognition observed here may highlight the importance of reproduction, specifically sperm allocation and avoidance of sexual cannibalism, on the evolution of sensory ecology and cognition within this lineage.

The deep-ocean carbon cycle is poorly quantified. An abyssal benthic rover was developed to make long time-series measurements of seafloor processes related to organic carbon remineralization and sequestration. Benthic Rover II (BR-II) is an autonomous dual-tracked vehicle that measures bottom water temperature and oxygen concentration, current velocity, and sediment community oxygen consumption (SCOC; respiration). BR-II is programmed to transit with low surface-contact pressure across the seafloor, photograph bottom conditions, and stop regularly to occupy respirometer incubation sites, with deployment periods up to 1 year. Now, continuously operational at a 4000-m station in the northeast Pacific over 5 years, substantial weekly, seasonal, annual, and episodic events have been recorded, which are critical to assessing the deep-ocean carbon cycle. There was a significant increase in phytodetritus cover (

Female octopuses are known to store sperm from multiple males they encounter throughout a breeding season, before laying a single clutch with mixed paternity. Although octopuses display a broad range of precopulatory behaviours, and both sperm competition and cryptic female choice have been hypothesized to occur, the current understanding of how these processes influence resulting paternity remains limited. This study aimed to identify behavioural factors associated with paternity patterns and the capacity of females to bias paternity postcopulation to specific males in the southern blue-ringed octopus, Hapalochlaena maculosa. Genetic markers and controlled, sequential, laboratory pairings of genotyped individuals were used to examine paternity patterns and compare them to relative signatures of male sperm remaining in female oviducal glands after egg laying. Multiple paternity was discovered in all 12 laboratory-reared clutches. There was no indication that the relative time spent in copulation affected the resulting paternity. Males that waited for females to terminate the copulation had greater paternity when they were the first candidate male, but this was not the case among second candidate males. The relative quantities of candidate male alleles detected in female oviducal glands after egg laying were consistent with relative paternity of the candidate males in all but three cases. In one of these, sibship analysis revealed that the male that obtained less paternity than expected was in fact the female's full-sibling brother. Although this study found no evidence for female postcopulatory selection of male sperm, anecdotal evidence suggests that female H. maculosa might benefit from polyandry if chemical processes can favour clutch fertilization by unrelated males. Future studies, investigating paternity bias among genotyped males of varying, but known relatedness to the female, might help to validate this pattern.

The southern blue‐ringed octopus, Hapalochlaena maculosa (Hoyle, 1883) lacks a planktonic dispersal phase, yet ranges across Australia's southern coastline. This species’ brief and holobenthic life history suggests gene flow might be limited, leaving distant populations prone to strong genetic divergence. This study used 17,523 genome‐wide SNP loci to investigate genetic structuring and local adaptation patterns of H. maculosa among eight sampling sites along its reported range. Within sites, interrelatedness was very high, consistent with the limited dispersal of this taxon. However, inbreeding coefficients were proportionally lower among sites where substructuring was not detected, suggesting H. maculosa might possess a mechanism for inbreeding avoidance. Genetic divergence was extremely high among all sites, with the greatest divergence observed between both ends of the distribution, Fremantle, WA, and Stanley, TAS. Genetic distances closely followed an isolation by geographic distance pattern. Outlier analyses revealed distinct selection signatures at all sites, with the strongest divergence reported between Fremantle and the other Western Australian sites. Phylogenetic reconstructions using the described sister taxon H. fasciata (Hoyle, 1886) further supported that the genetic divergence between distal H. maculosa sites in this study was equivalent to that of between established heterospecifics within this genus. However, it is advocated that taxonomic delineations within this species should be made with caution. These data indicate that H. maculosa forms a clinal species pattern across its geographic range, with gene flow present through allele sharing between adjacent populations. Morphological investigations are recommended for a robust resolution of the taxonomic identity and ecotype boundaries of this species.

The Metabolic Theory of Ecology (MTE) posits that metabolic rate controls ecological processes, such as the rate of resource uptake, from the individual‐ to the ecosystem‐scale. Metabolic rate has been found empirically to be an exponential function of whole organism body mass. We test a fundamental assumption of MTE, whether resource uptake scales to metabolism, by examining detritivores accessing a single common resource pool, an ideal study case. We used an existing empirical model of ingestion for aquatic deposit feeders adjusted for temperature to test whether ingestion by abyssal deposit feeders conforms to MTE‐predicted feeding rates. We estimated the sediment deposit‐feeding rates of large invertebrates from two abyssal study sites using time‐lapse photography, and related those rates to body mass, environmental temperature, and sediment organic matter content using this framework. Ingestion was significantly related to individual wet mass, with a mass‐scaling coefficient of 0.81, with 95% confidence intervals that encompass the MTE‐predicted value of 0.75, and the same pattern determined in other aquatic systems. Our results also provide insight into the potential mechanism through which this fundamental assumption operates. After temperature correction, both deep‐ and shallow‐water taxa might be summarized into a single mass‐scaled ingestion rate.

Chemoreception cues potentially influence intraspecific interactions of cephalopods, including mate choice. However, at present there is limited empirical evidence demonstrating whether cephalopods can use olfaction to identify the sex or identity of conspecifics. This study examined the responses of the southern blueringed octopus, Hapalochlaena maculosa (Hoyle, 1883), to conspecific odours during controlled laboratory trials. The ventilation rates in aquaria of 25 wild-sourced animals were measured during four treatments: baseline, sea water, sea water containing male conspecific odour and sea water containing female conspecific odour. When used as 'receivers' in trials, female H. maculosa significantly increased their ventilation rates in response to male odours, but not to female odours. However, female response decreased significantly with the receiver's size during female-odour treatments. The ventilation rates of male H. maculosa were statistically similar in all treatments. However, their ventilation rates showed a significant progressive increase over the observation period during male and female-odour treatments. Eighteen of these animals (nine females and nine males) were used in focal-animal trials 1 week after odour-cue experiments. Of these individuals, females were significantly more receptive to copulation attempts, and spent significantly more time per day in copulation, with males whose odours had elicited a weaker ventilation response in prior trials. These results suggest that female H. maculosa can use chemosensory cues to discriminate the sex, and possibly identity, of conspecifics and that this information might influence their mate choice. However, the mechanisms underlying these responses and subsequent copulatory access to females by males remain unknown.

Measuring the quantity and composition of sinking particulate matter is key to understanding biogeochemical processes in the ocean. This has been done in the past with sequencing sediment traps, which collect and store particulate matter in sample bottles for subsequent laboratory analysis. Having a limited number of bottles, these traditional traps force the user to choose between finer time resolution and longer deployment duration. We have built a new sediment trap that analyzes the collected material in situ, eliminating the need to preserve and store the samples. This new instrument, the Sedimentation Event Sensor (SES), captures macro images of the sample with front and back lighting, and takes fluorometric measurements in two bands as proxies for the presence of chlorophyll a and accessory pigments. The SES can process 6200 samples during a single deployment, which is the equivalent of 15 samples per day for more than a year. Here, we describe the design of the SES and present the results of its first three deployments at 3910 m depth. Images and fluorometry data revealed high variability of sinking particulate matter composition on the order of hours. Sedimentation patterns detected by the SES largely agreed with mass flux patterns measured from traditional traps deployed concurrently nearby. Given the functional differences, the SES is best used to complement rather than replace traditional sediment traps.

The deep ocean benthic environment plays a role in long-term carbon sequestration. Understanding carbon cycling in the deep ocean floor is critical to evaluate the impact of changing climate on the oceanic systems. Linear inverse modeling was used to quantify carbon transfer between compartments in the benthic food web at a long time-series study site in the abyssal northeastern Pacific (Station M). Linear inverse food web models were constructed for three separate years in the time-series when particulate organic carbon (POC) flux was relatively high (1990: 0.63 mean mmol C m?2 d?1), intermediate (1995: 0.24) and low (1996: 0.12). Carbon cycling in all years was dominated by the flows involved in the microbial loop; dissolved organic carbon uptake by microbes (0.80–0.95 mean mmol C m?2 d?1), microbial respiration (0.52–0.61), microbial biomass dissolution (0.09–0.18) and the dissolution of refractory detritus (0.46–0.65). Moreover, the magnitude of carbon flows involved in the microbial loop changed in relation to POC input, with a decline in contribution during the high POC influxes, such as those recently experienced at Station M. Results indicate that during high POC episodic pulses the role of faunal mediated carbon cycling would increase. Semi-labile detritus dominates benthic faunal diets and the role of labile detritus declined with increased total POC input. Linear inverse modeling represents an effective framework to analyze high-resolution time-series data and demonstrate the impact of climate change on the deep ocean carbon cycle in a coastal upwelling system.

Long time-series studies are critical to assessing impacts of climate change on the marine carbon cycle. A 27-year time-series study in the abyssal northeast Pacific (Sta. M, 4000 m depth) has provided the first concurrent measurements of sinking particulate organic carbon supply (POC flux) and remineralization by the benthic community. Sediment community oxygen consumption (SCOC), an estimate of organic carbon remineralization, was measured in situ over daily to interannual periods with four different instruments. Daily averages of SCOC ranged from a low of 5.0 mg C m−2 day−1 in February 1991 to a high of 31.0 mg C m−2 day−1 in June 2012. POC flux estimated from sediment trap collections at 600 and 50 m above bottom ranged from 0.3 mg C m−2 day−1 in October 2013 to 32.0 mg C m−2 day−1 in June 2011. Monthly averages of SCOC and POC flux correlated significantly with no time lag. Over the long time series, yearly average POC flux accounted for 63 % of the estimated carbon demand of the benthic community. Long time-series studies of sediment community processes, particularly SCOC, have shown similar fluctuations with the flux of POC reaching the abyssal seafloor. SCOC quickly responds to changes in food supply and tracks POC flux. Yet, SCOC consistently exceeds POC flux as measured by sediment traps alone. The shortfall of ~37 % could be explained by sediment trap sampling artifacts over decadal scales including undersampling of large sinking particles. High-resolution measurements of SCOC are critical to developing a realistic carbon cycle model for the open ocean. Such input is essential to evaluate the impact of climate change on the oceanic carbon cycle, and the long-term influences on the sedimentation record. Electronic supplementary material The online version of this article (doi:10.1007/s10498-016-9293-3) contains supplementary material, which is available to authorized users.

Holothurians are among the most abundant benthic megafauna at abyssal depths, and important consumers and bioturbators of organic carbon on the sea floor. Significant fluctuations in abyssal holothurian density are often attributed to species-specific responses to variable particulate organic carbon flux (food supply) stemming from surface ocean events. We report changes in densities of 19 holothurian species at the abyssal monitoring site Station M in the northeast Pacific, recorded during 11 remotely operated vehicle surveys between Dec 2006 and Oct 2014. Body size demographics are presented for Abyssocucumis abyssorum, Synallactidae sp. 1, Paelopatides confundens , Elpidia sp. A, Peniagone gracilis , Peniagone papillata , Peniagone vitrea , Peniagone sp. A, Peniagone sp. 1, and Scotoplanes globosa . Densities were lower and species evenness was higher from 2006–2009 compared to 2011–2014. Food supply of freshly-settled phytodetritus was exceptionally high during this latter period. Based on relationships between median body length and density, numerous immigration and juvenile recruitment events of multiple species appeared to take place between 2011 and 2014. These patterns were dominated by elpidiids (Holothuroidea: Elasipodida: Elpidiidae), which consistently increased in density during a period of high food availability, while other groups showed inconsistent responses. We considered minimum body length to be a proxy for size at juvenile recruitment. Patterns in density clustered by this measure, which was a stronger predictor of maximum density than median and mean body length.

This study investigates the evolution of deep-sea lebensspuren assemblages before, during, and after five high-energy episodes over a storm-events period lasting 25 days. Bioturbational changes were characterized through brief benthic storm events in the northeastern Pacific at the abyssal time-series site Station M (4000 m depth). Quantification of seafloor coverage was processed to evaluate variations on the substratum type. A total of 15 lebensspuren morphotypes were identified. Most traces could be associated with feeding faecal casts, crawling tracks, dwellings and resting structures. Lebensspuren assemblages were similar before and after the storm-events period; full assemblage was re-established in one week. This high energy period was associated with an impoverishment of lebensspuren abundance and assemblage diversity. Only elpidiid holothurian feeding faecal casts recorded a notable increase in abundance during this period of high energy. In addition, this energetic stage involved the appearance of exhumed surface patches. Holothurian feeding activity appeared to have been primarily influenced by the local-scale erosion and re-suspension of unconsolidated surface sediment, which led to the reorganization of organic matter resources. We propose the mobility of elpidiid holothurians allowed them to gain a competitive advantage in obtaining these new resources. This research presents a novel relationship between lebensspuren, faunal activity, and bottom currents that broadens our understanding of benthic community responses to deep-sea bottom currents. Finally, we discuss these results as they pertain to the fossil record to assess how bioturbational structure development could be controlled by substratum type, organic matter availability and duration of energetic episodes.

Biological communities on the abyssal plain are largely dependent on detritus from the surface ocean as their main source of energy. Seasonal fluctuations in the deposition of that detritus cause temporal variations in the quantity and quality of food available to these communities, altering their structure and the activity of the taxa present. However, direct observations of energy acquisition in relation to detritus availability across megafaunal taxa in abyssal communities are few. We used time-lapse photography and coincident measurement of organic matter flux from water column sediment traps to examine the impact of seasonal detrital inputs on resource acquisition by the deposit feeding megafauna assemblages at two sites: Station M (Northeast Pacific, 4000 m water depth) and the Porcupine Abyssal Plain Sustained Observatory (PAP-SO, Northeast Atlantic 4850 m water depth). At Station M, studied over 18-months, the seasonal particle flux was followed by a salp deposition event. At that site, diversity in types of deposit feeding was related to seabed cover by detritus. At PAP-SO, studied over 30 months, the seasonal particle flux consisted of two peaks annually. While the two study sites were similar in mean flux (~8.0 mgC m−2 d−1), the seasonality in the flux was greater at PAP-SO. The mean overall tracking at PAP-SO was five times that of Station M (1.9 and 0.4 cm2 h−1, respectively); both are likely underestimated because tracking by some common taxa at both sites could not be quantified. At both sites, responses of deposit-feeding megafauna to the input of detritus were not consistent across the taxa studied. The numerically-dominant megafauna (e.g. echinoids, large holothurians and asteroids) did not alter their deposit feeding in relation to the seasonality in detrital supply. Taxa for which deposit feeding occurrence or rate were correlated to seasonality in particle flux were relatively uncommon (e.g. enteropneusta), known to cache food (e.g. echiurans), or to be highly selective for fresh detritus (e.g. the holothurian Oneirophanta mutabilis). Thus, the degree of seasonality in deposit feeding appeared to be taxon-specific and related to natural history characteristics such as feeding and foraging modes.

Megafaunal seafloor assemblages on the Monterey Fan in the NE Pacific (Station M, 4000 m depth) were studied between 2006–2018 using remotely operated vehicles (ROVs) as part of a continuing time-series study that began in 1989. Since 2006 we identified nearly 120,000 individual animals representing over 142 morphospecies, and observed continuous changes in the megafaunal assemblage. This study, which tracked variation in observed morphospecies over a 13-year period, is one of the most detailed long-term records of megafaunal change for abyssal depths. Our investigation shows that new variations continued to emerge, reinforcing the concept that the deep-sea is dynamic over short time scales, rather than static over long periods. Some species were uncommon, but later observed in high numbers, then decreased to very low or undetectable levels (e.g. Elpidia sp. A), while others (e.g. Psychropotes longicauda) exhibited a relatively persistent presence with less fluctuation in abundance. Decreasing total echinoderm density from 2013–2018 did not correspond with the continued occurrence of large episodic POC flux events between 2016–2018. This may be attributed to the quality of food supply arriving at the seafloor and the varied ability of organisms to utilize it. Long-term tracking (30 years) of 10 specific epibenthic echinoderm species originally quantified from camera-sled images shows a pattern of assemblage structure, perhaps returning toward the composition observed in the 1990s and early 2000s. Many questions remain as to how this abyssal site and others will change with continued, and potentially increasing, anthropogenic change in the upper ocean. For example, the marine heat anomaly known as the ‘Warm Blob’ may have influenced major ecological processes at the abyssal seafloor in terms of morphospecies and functional group composition due to changes in POC flux. The degree of dynamism continues to indicate that ad hoc or short-term investigations provide a limited perspective for assessing community structure in conservation or resource exploitation impact assessment studies in the deep sea.

High-temporal-resolution views of particle flux to the abyssal benthic boundary layer are provided for an eight-month period (October 2014–June 2015) at the long-term monitoring site Station M within the California Current ecosystem. Contributions of fecal pellets and aggregates to particulate organic carbon (POC) flux at 3900 m depth were estimated based on optical sediment trap (Sedimentation Event Sensor) images captured as a time-series of 2 h collections. POC flux estimated from Sedimentation Event Sensor (SES) images explained variation in carbon consumption and the carbon budget balance (supply – demand) with finer resolution than POC flux measurements from bulk collections by a concurrently deployed conventional sediment trap. Indicators of particle transport by benthic boundary layer currents and active transport by zooplankton were evaluated by comparing SES-estimated POC flux to measured current speed and direction, hours since solar noon, and modeled lunar illumination at the surface. Influence of particles (fecal pellets and aggregates) on the carbon budget was evaluated by comparing particle-specific contributions to POC flux with sediment community oxygen consumption (SCOC) measured by the Benthic Rover at 4000 m depth. During the eight-month sampling period, salp fecal pellets delivered an estimated 45% of the total POC flux to the benthic boundary layer and were responsible for an estimated 74% of a temporary carbon surplus in May and June 2015. Salp fecal pellets also appeared to be the primary source of chlorophyll peaks at the site. By contrast, most aggregates appeared to be lower-quality particles possibly sourced from lateral advection and local rebound of recently-settled detritus, which settled according to spring-neap tidal oscillations. Some aggregates may have been fresher, as suggested by non-linear relationships with SCOC and the carbon budget balance. Results suggest sinking particles packaged in surface waters and reaching abyssal depths in fresh condition (e.g. salp fecal pellets) had a greater influence on carbon consumption (e.g. SCOC) and the carbon budget balance than more refractory particles.

A time series study from 1989 to 2017 indicates that, increasingly, carbon export to abyssal sediments in the California Current Ecosystem (CCE), 220 km west of the central California coast (Sta. M), occurs as rapidly sinking pulses of particulate organic carbon (POC). Nearly continuous sediment trap collections confirm that POC export to 3400 m increased significantly after 2011 with carbon attenuation (as fraction of POC remineralized) ranging from a low of 57% to a high of 77% during periods of pulsed flux. All of the major pulse events for the period resulted in the delivery of detrital aggregates that covered part or all of the sediment surface as an organic carbon rich layer at ~4000 m depth. However, the magnitude of the measured Sediment Community Oxygen Consumption (SCOC) did not increase proportionally to the organic carbon inventory change. Here, a model of oxygen consumption, informed by the time series data at Sta. M in the CCE, suggests that aggregate flocs constitute a major source for benthic carbon and a barrier to mass transport of oxygen, leading to reduced carbon attenuation in surface sediments. The correlation of POC delivery with aggregate coverage shows that the majority of POC delivery during pulse events is likely to consume all of the oxygen within the aggregates. Results indicate that an increasing fraction of POC reaches the abyssal sediments at Sta. M under conditions that support increased net burial of carbon. This finding is significant in the context of the fraction of the total POC flux that occurs as pulse events in this important upwelling region. During the period from 2011 to 2017, a third of the total POC flux resulted in aggregate flocs that covered a significant portion of the sediment surface (>47%). Following the 2015–2016 El Nino period the flocs became a dominant feature of the sediment surface. More than 80% of the POC flux to near bottom sediment traps in 2017 occurred coincident with aggregate floc cover of more than 90% of the sediments. The resultant physical barrier to oxygen transport and relatively low consumption of newly delivered carbon indicate conditions that are more typical of environments having low oxygen bottom waters.

Gelatinous zooplankton are prominent fauna in the deep ocean, especially in the water column associated with the sea floor. This interface zone, the benthic boundary layer, is critical to biogeochemical exchanges between pelagic and benthic communities. A conspicuous member of this benthic boundary layer community in the abyssal Northeast Pacific (Sta. M; 4000 m depth) is the hydrozoan medusa, Benthocodon pedunculata. A 3-year time-series study was conducted of B. pedunculata from October 2014 to November 2017 using an autonomous time-lapse camera system and acoustic current meter deployed on the sea floor. Remotely operated vehicle benthic video transects and collections were also conducted during six servicing cruises for the long-term instruments. Over three years, a total of 123,887 B. pedunculata were recorded in hourly images with densities ranging from 0 to a high of 33 individuals m−3 in March 2016. Density of B. pedunculata was highest when current speeds were low, and declined precipitously as speed increased beyond ~1 cm s−1. Movement of B. pedunculata was parallel to the continental margin in northwest and southeast directions. The large numbers of B. pedunculata observed over this 3-year study suggests their ecological importance in the benthic boundary layer food web at Sta. M.

Significance Ignoring temporal fluctuations in the oceanic carbon budget leads to a significant misrepresentation of the cycling of organic matter from production in surface waters to consumption and sequestration in the abyssal ocean. A 29-year time series (1989 to 2017) of particulate organic carbon (POC) fluxes and sea-floor measurements of sediment community oxygen consumption (SCOC) revealed episodic, high-magnitude events over the past 7 years. Time lags between changes in satellite-estimated export flux, POC flux and SCOC varied from 0 to 70 days. A commonly used model to estimate carbon flux through the water column significantly underestimated the measured carbon fluxes by almost 50%. Episodic pulses of organic carbon into the deep sea must be accounted for to balance the oceanic carbon budget., Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events (≥mean + 2 σ), and 43% from 2011 to 2017. From 2011 to 2017, when high-resolution SCOC data were available, time lags between changes in satellite-estimated export flux (EF), POC flux, and SCOC on the sea floor varied between six flux events from 0 to 70 days, suggesting variable remineralization rates and/or particle sinking speeds. Half of POC flux pulse events correlated with prior increases in EF and/or subsequent SCOC increases. Peaks in EF overlying Station M frequently translated to changes in POC flux at abyssal depths. A power-law model (Martin curve) was used to estimate abyssal fluxes from EF and midwater temperature variation. While the background POC flux at 3,400-m depth was described well by the model, the episodic events were significantly underestimated by ∼80% and total flux by almost 50%. Quantifying episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of POC sequestration and understanding the global carbon cycle.

Motivation The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. Main types of variables included The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. Spatial location and grain BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). Time period and grain BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. Major taxa and level of measurement BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates. Software format .csv and .SQL., Global Ecology and Biogeography, 27 (7), ISSN:1466-822X, ISSN:1466-8238

Soil erosion associated with land-use change is considered one of the greatest human threats to coral reef ecosystems globally. To account for sediment runoff in land–sea planning, spatially and temporally dynamic models are needed that predict where soil loss is occurring, in addition to where sediments are travelling and settling in coastal marine areas. This assessment is particularly difficult given the complex three-dimensional movement of sediment in water bodies. This study assessed the vulnerability of key marine resources to sedimentation in Raja Ampat, Indonesia, by developing a coupled terrestrial and marine model that relied primarily on global datasets. The model predicted the quantities of sediment at river mouths, and the spatial extent over where this sediment disperses in the ocean. In total, 1850 km2 of coral reefs, marine protected areas, dive sites, pearl farms, and other benthic habitats in Raja Ampat were found within sediment plumes with varying degrees of impact. Two hypothetical land-use scenarios were created to illustrate the sensitivity of sedimentation on marine resources to development, and to compare future alternative management scenarios. The model provides a powerful tool for planners to understand how land management, and land-use change might affect marine resources, particularly in data-limited regions. Copyright © 2015 John Wiley & Sons, Ltd.

The southern blue-ringed octopus,Hapalochlaena maculosaHoyle (1883), is a nocturnal species that exhibits a mating system in which females hold sperm from multiple males over a one to two month breeding window before laying a single egg clutch. Contrary to most studied animal mating systems where anisogamy exists, gamete package production is limited for both males and females of this species (approx. 50 spermatophores/eggs). This presents an animal model for studying aspects of sperm competition and dynamic mate choice behaviours. The present study reports on the mating behaviour ofH. maculosaobserved under laboratory conditions using infrared closed-circuit television video footage. Rates of male copulation attempts increased with male size, while female receptivity to mating attempts increased with female size, resulting in larger animals of both sexes gaining more copulations and spending more time per day in copulation. There was some evidence of female preference of larger males, but no male preference of females based on measured morphological traits. Both sexes terminated copulations in equal frequencies but male-terminated copulations were significantly shorter in duration. Males were more likely to terminate copulation early with females they had previously mated with, however were less likely to do so if the female had recently mated with a different male. Among male-terminated copulations, males mated for longer with females that had previously mated with other males in the trial. Male–male mounts were as common as male–female mounts, suggesting that maleH. maculosaare not able to discriminate the sex of conspecifics. These findings suggest male strategic allocation of spermatophores based female mating history is an important factor influencing mating behaviours of this species.

Aggressive constricting including asphyxiation was observed in wild octopuses (Octopus cyanea Gray, 1849, and Wunderpus photogenicus Hochberg, Norman & Finn, 2006). The distal portion of a dorsolateral arm formed a loop around the mantle of another octopus, in at least one case preventing the flow of water into the mantle, over the gills and out of the funnel. Constricting also may have prevented the subordinate individual from releasing ink, a possible irritant and predator attractant. A female O. cyanea used constricting as a form of fatal aggression to asphyxiate a male as part of apparent sexual cannibalism. This female killed a male with which she was mating using the ‘distance’ position. Constriction allowed a W. photogenicus to win during physical interspecific aggression with a close relative, Thaumoctopus mimicus Norman & Hochberg, 2005. This action took place near an immediately available food source and interrupted foraging by T. mimicus, providing possible evidence of interference competition ...

The deep ocean, covering a vast expanse of the globe, relies almost exclusively on a food supply originating from primary production in surface waters. With well-documented warming of oceanic surface waters and conflicting reports of increasing and decreasing primary production trends, questions persist about how such changes impact deep ocean communities. A 24-y time-series study of sinking particulate organic carbon (food) supply and its utilization by the benthic community was conducted in the abyssal northeast Pacific (~4,000-m depth). Here we show that previous findings of food deficits are now punctuated by large episodic surpluses of particulate organic carbon reaching the sea floor, which meet utilization. Changing surface ocean conditions are translated to the deep ocean, where decadal peaks in supply, remineralization, and sequestration of organic carbon have broad implications for global carbon budget projections.

Previous surveys of the reef-associated ichthyofauna of the Raja Ampat Islands in West Papua, Indonesia recorded a total of 1,320 species of reef fishes, including 271 species of Gobiidae. A recent survey focused on the cryptic gobies of Raja Ampat resulted in 36 new records (including nine species of both Trimma and Eviota). Sixteen of the new records are currently undescribed species, with seven of these identified as Raja Ampat endemics, while the remaining nine species are also known from localities outside Raja Ampat in the western Pacific. Five species previously recorded from the area have been re-identified, two of them representing undescribed species, and a new record from the literature has been added. This brings the total number of reef fishes known from Raja Ampat waters to 1,357, of which 308 belong to the Gobiidae. The number of species (including the undescribed taxa) apparently endemic to the Bird's Head Peninsula of West Papua now totals 33.

The Bird's Head Seascape located in eastern Indonesia is the global epicenter of tropical shallow water marine biodiversity with over 600 species of corals and 1,638 species of coral reef fishes. The Seascape also includes critical habitats for globally threatened marine species, including sea turtles and cetaceans. Since 2001, the region has undergone rapid development in fisheries, oil and gas extraction, mining and logging. The expansion of these sectors, combined with illegal activities and poorly planned coastal development, is accelerating deterioration of coastal and marine environments. At the same time, regency governments have expanded their marine protected area networks to cover 3,594,702 ha of islands and coastal waters. Low population numbers, relatively healthy natural resources and a strong tenure system in eastern Indonesia provide an opportunity for government and local communities to collaboratively manage their resources sustainably to ensure long-term food security, while meeting their development aspirations.

Squids of the family Bathyteuthidae have generally been infrequently encountered in their deep-sea habitat. Remotely operated vehicles were used to observe seven individuals in situ in the Monterey Submarine Canyon, CA, USA. One of these was a female Bathyteuthis berryi holding a sheet with approximately 360 embedded embryos. Examination of this female after collection revealed the presence of a seminal receptacle on the buccal membrane. We present some potential costs and benefits of post-spawning egg care, a strategy that is now known for two families of deep-dwelling squids, but may turn out to be more common with the increasing exploration of the deep sea.

Some pelagic marine larvae possess anti-predator chemical defenses. Occasionally, toxic adults imbue their young with their own defensive cocktails. We examined paralarvae of the greater blue-ringed octopus (Hapalochlaena lunulata) for the deadly neurotoxin tetrodotoxin (TTX), and if present, whether TTX conferred protection to individual paralarvae. Paralarvae of H. lunulata possessed 150 ± 17 ng TTX each. These paralarvae appeared distasteful to a variety of fish and stomatopod predators, yet food items spiked with 200 ng TTX were readily consumed by predators. We conclude that TTX alone does not confer individual protection to paralarvae of H. lunulata, and that they possess an alternative defense. In larger doses, tetrodotoxin is a deterrent to the predatory stomatopod Haptosquilla trispinosa (mean dose = 3.97 μg/g). This corresponds to 12–13 paralarvae per predator based on the TTX levels of the clutch we examined. Thus, the basic assumption that individual paralarvae of H. lunulata are defended by TTX alone was disproved. Instead, functionality of TTX levels in paralarvae may arise through alternative selective pathways, such as deterrence to parasites, through kin selection, or against predator species not tested here.

The ‘Mimic Octopus’Thaumoctopus mimicus Norman & Hochberg, 2005 exhibits a conspicuous primary defence mechanism (high-contrast colour pattern during ‘flatfish swimming’) that may involve facultative imperfect mimicry of conspicuous and/or inconspicuous models, both toxic and non-toxic (Soleidae and Bothidae). Here, we examine relationships between behavioural and morphological elements of conspicuous flatfish swimming in extant octopodids (Cephalopoda: Octopodidae), and reconstructed ancestral states, to examine potential influences on the evolution of this rare defence mechanism. We address the order of trait distribution to explore whether conspicuous flatfish swimming may be an exaptation that usurps a previously evolved form of locomotion for a new purpose. Contrary to our predictions, based on the relationships we examined, flatfish swimming appears to have evolved concurrently with extremely long arms, in a clade of sand-dwelling species. The conspicuous body colour pattern displayed by swimming T. mimicus may represent a secondary adaptation potentially allowing for mimicry of a toxic sole, improved disruptive coloration, and/or aposematic coloration. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 68–77.

Abdopus aculeatus engages in frequent aggression and copulation, exhibits male mate-choice, and employs multiple mating tactics. Here we draw upon established hypotheses to compare male-male aggression (MMA) and male-female aggression (MFA), as they relate to their mating behavior in the wild. When contesting for females, males appear to balance mate preference (resource value) with perceived chances of winning contests (resource holding potential). Although males spent more time mating with and contesting for large "Adjacent Guarded" females (those occupying a den within arm's reach of a large "Adjacent Guarding" male), they exhibited higher rates of aggression over nonadjacent "Temporarily Guarded" females that may be more accessible. The major determinant of male-male aggressive success was size, and this factor may dictate the expression of conditional mating tactics in males. "Adjacent Guarding" males were the largest and most aggressively successful males, earning the most time copulating with females. They are considered to have the highest resource holding potential (RHP) in MMA. By contrast, in MFA, some larger individuals fled from smaller individuals, indicating that RHP appears to be a function of both size and sex in intersexual aggression. This result suggests variation in aggressiveness, or potential for severe injury-even sexual cannibalism during MFA. Male-female aggression may also be influenced by the sexual nonreceptivity of some individuals, or attempts by both sexes to increase foraging behavior by delaying mate-guarding activity.

The mating system of Abdopus aculeatus incorporates sneaker matings, mate guarding, sex-specific body patterns, frequent copulations, and male–male competition for mates, making it more similar to that of aggregating decapod cephalopods than any previously known octopus social system. Large male–female A. aculeatus occupy ‘Adjacent’ (GA) dens and copulate frequently in mate-guarding situations over successive days. Nearby individuals copulate in ‘Temporary guarding’ (GT) and ‘Transient’ (T; non-guarding) situations, the latter of which can involve ‘Sneaker’ (S) mating. In a focal animal study of these octopuses in the wild (Sulawesi, Indonesia) we addressed the hypotheses that they demonstrate: (1) precopulatory mate choice, (2) differential copulation rates by individuals employing different mating tactics, and (3) distant sex identification. We quantified daily copulation rates of A. aculeatus of reproductive size as well as aspects of copulation duration, display, mate-competition, and mate rejection. Mating tactic correlated with daily copulation rates. ♂GA spent significantly more time copulating than did ♂T, while ♀GA spent more than twice as much time per day in copula than did other females. Sneaker copulations lasted longer than those by males adopting other tactics. Mate-guarding was an effective and important tactic used by males to temporarily monopolize mating with apparently non-selective females. Males demonstrated clear pre-copulatory mate choice by guarding and mating repeatedly with large females (typically ♀GA). While foraging alone away from the den, ♂G procured ‘Transient’ copulations with unguarded females. However, mate-guarding reduced the amount of time ♂G were alone and may impede their ability to seek out new mates. Low-copulation rates by ♀T, the smallest female tactic on average, may reflect this trade-off between mate preference and mate-searching by males, or non-receptivity of some females. A male-typical body pattern (black and white stripes) appeared to facilitate distant sex identification. Although mating and aggression were often initiated before contact between individuals, same-sex copulations and intense male–female aggression were rare. By contrast frequent male–female copulations and intense male–male aggression were consistent behavioral components of mating in A. aculeatus at these sites. Because the behavioral and ecological characters conducive to this complex system are not exclusive to A. aculeatus, it is possible that other octopuses exhibit some or all of these behaviors.

Long-term observing of our world's oceans is crucial to understanding climate change. Innovation and collaboration are needed to achieve sustainable oceanic time series.

The 25 year time-series collected at Station M, ~4000m on the Monterey Deep-sea Fan, has substantially improved understanding of the role of the deep-ocean benthic environment in the global carbon cycle. However, the role of deep-ocean benthic megafauna in carbon bioturbation, remineralization and sequestration is relatively unknown. It is important to gather both accurate and precise measurements of megafaunal community abundance, size distribution and biomass to further define their role in deep-sea carbon cycling and possible sequestration. This study describes initial results from a stereo camera system attached to a remotely operated vehicle and analyzed using the EventMeasure photogrammetric measurement software to estimate the density, length and biomass of 10 species of mobile epibenthic megafauna. Stereo length estimates were compared to those from a single video camera system equipped with sizing lasers and analyzed using the Monterey Bay Aquarium Research Institute’s Video Annotation and Reference System. Both camera systems and software were capable of high measurement accuracy and precision (

Changes in habitat-forming organisms can have complex consequences for associated species. Sessile epibenthic glass “plate” sponges (Porifera: Hexactinellida) are conspicuous inhabitants of soft-sediment abyssal areas and their siliceous spicules create persistent spicule patches on the seafloor. Sponge spicule patch density, spatial dispersion, and percent cover were examined over a seven-year period (2006–2013) using remotely operated vehicle videos from Station M in the abyssal northeast Pacific (50˚00N, 123˚00W, ~4,000 m depth). There was an apparent large increase in newly dead plate sponges in February 2007 compared with December 2006, with this trend continuing through June 2007 (mean 0.03 % cover increasing to 0.33 %). A second increase in mean percent cover of dead plate sponges occurred from May 2011 (0.24 %) through June 2012 (0.60 %). Among the 28 megafaunal taxa occurring in association with the patches, the distributions of three taxa [two sponge taxa (Porifera) and brittle stars (Ophiuroidea)] suggested selectivity for the sponge spicule patches. The community structure of visible megafauna within sponge spicule patches was different when compared with that outside the patches suggesting that the sponges, after death, provide preferred habitat patches for certain benthic megafauna. These findings indicate that sponge spicule patches contribute to habitat heterogeneity in space and time. Electronic supplementary material The online version of this article (doi:10.1007/s00227-014-2609-1) contains supplementary material, which is available to authorized users.

The abyssal seafloor community in the NE Pacific (Station M, ∼4000m depth) was studied between 2006 and 2012 using remotely operated vehicles (ROVs) as part of a continuing 24-year time-series study. New patterns continue to emerge showing that the deep-sea can be dynamic on short time scales, rather than static over long periods. In just over 2years the community shifted from a sessile, suspension-feeding, sponge-dominated community to a mobile, detritus-feeding, sea cucumber-dominated assemblage. In 2006 megafaunal diversity (Simpson’s Diversity Index, SDI) was high, yet the community was depauperate in terms of density compared to later periods. Over an 18-month period beginning in spring 2011, the densities of mobile organisms increased by nearly an order of magnitude while diversity decreased below 2006 levels. In late 2012 four sea cucumbers (two Peniagone spp., Elpidia sp. A, and Scotoplanes globosa) were at the highest densities recorded since investigations began at Station M in 1989. For a group of 10 echinoderms investigated over the entire study period, we saw evidence of a long-term cycle spanning 2 decades. These changes can be tied to a variable food supply originating in shallow water. Large variations over decadal-scales indicate that remote abyssal communities are dynamic and likely subject to impacts from anthropogenic changes like ocean warming, acidification, and pollution manifested in the upper ocean. The degree of dynamism indicates that one-time or short-term investigations are not sufficient for assessing biological community structure in conservation or exploitation studies in the deep sea.

A large bloom of Salpa spp. in the northeastern Pacific during the spring of 2012 resulted in a major deposition of tunics and fecal pellets on the seafloor at ~ 4000 m depth (Sta. M) over a period of 6 months. Continuous monitoring of this food pulse was recorded using autonomous instruments: sequencing sediment traps, a time-lapse camera on the seafloor, and a bottom-transiting vehicle measuring sediment community oxygen consumption (SCOC). These deep-sea measurements were complemented by sampling of salps in the epipelagic zone by California Cooperative Ocean Fisheries Investigations. The particulate organic carbon (POC) flux increased sharply beginning in early March, reaching a peak of 38 mg C m-2 d-1 in mid-April at 3400 m depth. Salp detritus started appearing in images of the seafloor taken in March and covered a daily maximum of 98% of the seafloor from late June to early July. Concurrently, the SCOC rose with increased salp deposition, reaching a high of 31 mg C m-2 d-1 in late June. A dominant megafauna species, Peniagone sp. A, increased 7-fold in density beginning 7 weeks after the peak in salp deposition. Estimated food supply from salp detritus was 97-327% of the SCOC demand integrated over the 6-month period starting in March 2012. Such large episodic pulses of food sustain abyssal communities over extended periods of time. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc.

This paper concisely summarizes major aspects of cephalopod biology, behavior, and ecology providing a backdrop against which neurobiology of these animals can be interpreted. Reproduction, camouflage, motor control, memory, learning, and behavioral ecology are introduced, and thorough literature reviews of these subjects are cited for further reading. The aim of this paper is to provide a general introduction to cephalopods for use by workers currently focused on other model systems.

Here we report for the first time that adult Hapalochlaena lunulata (Quoy & Gaimard, 1832), which has a vestigial ink sac, is capable of inking. Ink was released under three different agonistic conditions: female-female aggression, rejection of mating attempt, and when attacked by a predator. We observed no apparent reaction to the ink by the other animals involved in these interactions.

Studies on the longevity and migration patterns of wild animals rely heavily on the ability to track individual adults. Non-extractive sampling methods are particularly important when monitoring animals that are commercially important to ecotourism, and/or are rare. The use of unique body patterns to recognize and track individual vertebrates is well-established, but not common in ecological studies of invertebrates. Here we provide a method for identifying individual Wunderpus photogenicus using unique body color patterns. This charismatic tropical octopus is commercially important to the underwater photography, dive tourism, and home aquarium trades, but is yet to be monitored in the wild. Among the adults examined closely, the configurations of fixed white markings on the dorsal mantle were found to be unique. In two animals kept in aquaria, these fixed markings were found not to change over time. We believe another individual was photographed twice in the wild, two months apart. When presented with multiple images of W. photogenicus, volunteer observers reliably matched photographs of the same individuals. Given the popularity of W. photogenicus among underwater photographers, and the ease with which volunteers can correctly identify individuals, photo-identification appears to be a practical means to monitor individuals in the wild.

Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

SUMMARYSpeeds and variation in body form during crawling, bipedal walking,swimming and jetting by the shallow-water octopus Abdopus aculeatuswere compared to explore possible interactions between defense behaviors and biomechanics of these multi-limbed organisms. General body postures and patterns were more complex and varied during the slow mode of crawling than during fast escape maneuvers such as swimming and jetting. These results may reflect a trade-off between predator deception and speed, or simply a need to reduce drag during jet-propelled locomotion. Octopuses swam faster when dorsoventrally compressed, a form that may generate lift, than when swimming in the head-raised posture. Bipedal locomotion proceeded as fast as swimming and can be considered a form of fast escape (secondary defense) that also incorporates elements of crypsis and polyphenism (primary defenses). Body postures during walking suggested the use of both static and dynamic stability. Absolute speed was not correlated with body mass in any mode. Based on these findings the implications for defense behaviors such as escape from predation, aggression, and `flatfish mimicry' performed by A. aculeatus and other octopuses are discussed.

Here we report bipedal movement with a hydrostatic skeleton. Two species of octopus walk on two alternating arms using a rolling gait and appear to use the remaining six arms for camouflage. Octopus marginatus resembles a coconut, and Octopus ( Abdopus ) aculeatus , a clump of floating algae. Using underwater video, we analyzed the kinematics of their strides. Each arm was on the sand for more than half of the stride, qualifying this behavior as a form of walking.

Pelagic forms of the brown algae (Phaeophyceae) Sargassum spp. and their conspicuous rafts are defining characteristics of the Sargasso Sea in the western North Atlantic. Given rising temperatures and acidity in the surface ocean, we hypothesized that macrofauna associated with Sargassum in the Sargasso Sea have changed with respect to species composition, diversity, evenness, and sessile epibiota coverage since studies were conducted 40 years ago. Sargassum communities were sampled along a transect through the Sargasso Sea in 2011 and 2012 and compared to samples collected in the Sargasso Sea, Gulf Stream, and south of the subtropical convergence zone from 1966 to 1975. Mobile macrofauna communities exhibited changes in community structure and declines in diversity and evenness within a 6-month time period (August 2011–February 2012). Equivalent declines in diversity and evenness were recorded in the same region (Sargasso Sea, 25°–29°N) in 1972–1973. Recent community structures were unlike any documented historically, whether compared to sites of the same latitude range within the Sargasso Sea, or the broader historical dataset of sites ranging across the Sargasso Sea, Gulf Stream, and south of the subtropical convergence zone. Recent samples also recorded low coverage by sessile epibionts, both calcifying forms and hydroids. The diversity and species composition of macrofauna communities associated with Sargassum might be inherently unstable. While several biological and oceanographic factors might have contributed to these observations, including a decline in pH, increase in summer temperatures, and changes in the abundance and distribution of Sargassum seaweed in the area, it is not currently possible to attribute direct causal links.