Coastal upwelling drives ecosystem temporal variability from the surface to the abyssal seafloor.

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.

Tactical Tentacles: New Insights on the Processes of Sexual Selection Among the Cephalopoda.

The cephalopods (Mollusca: Cephalopoda) are an exceptional class among the invertebrates, characterised by the advanced development of their conditional learning abilities, long-term memories, capacity for rapid colour change and extremely adaptable hydrostatic skeletons. These traits enable cephalopods to occupy diverse marine ecological niches, become successful predators, employ sophisticated predator avoidance behaviours and have complex intraspecific interactions. Where studied, observations of cephalopod mating systems have revealed detailed insights to the life histories and behavioural ecologies of these animals. The reproductive biology of cephalopods is typified by high levels of both male and female promiscuity, alternative mating tactics, long-term sperm storage prior to spawning, and the capacity for intricate visual displays and/or use of a distinct sensory ecology. This review summarises the current understanding of cephalopod reproductive biology, and where investigated, how both pre-copulatory behaviours and post-copulatory fertilisation patterns can influence the processes of sexual selection. Overall, it is concluded that sperm competition and possibly cryptic female choice are likely to be critical determinants of which individuals' alleles get transferred to subsequent generations in cephalopod mating systems. Additionally, it is emphasised that the optimisation of offspring quality and/or fertilisation bias to genetically compatible males are necessary drivers for the proliferation of polyandry observed among cephalopods, and potential methods for testing these hypotheses are proposed within the conclusion of this review. Further gaps within the current knowledge of how sexual selection operates in this group are also highlighted, in the hopes of prompting new directions for research of the distinctive mating systems in this unique lineage.

Abyssal deposit-feeding rates consistent with the metabolic theory of ecology.

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.

Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific.

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.

Genome-wide comparisons reveal a clinal species pattern within a holobenthic octopod-the Australian Southern blue-ringed octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae).

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.

Behavior and Body Patterns of the Larger Pacific Striped Octopus.

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.

Deep ocean communities impacted by changing climate over 24 y in the abyssal northeast Pacific Ocean.

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.

Cephalopod neurobiology: an introduction for biologists working in other model systems.

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.

Papuan Bird's Head Seascape: emerging threats and challenges in the global center of marine biodiversity.

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.

Male-male and male-female aggression may influence mating associations in wild octopuses (Abdopus aculeatus).

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.

Individually unique body color patterns in octopus (Wunderpus photogenicus) allow for photoidentification.

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.

Locomotion by Abdopus aculeatus (Cephalopoda: Octopodidae): walking the line between primary and secondary defenses.

Speeds and variation in body form during crawling, bipedal walking, swimming and jetting by the shallow-water octopus Abdopus aculeatus were 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.

Underwater bipedal locomotion by octopuses in disguise.

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.