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Sustained observations provide critically needed data and understanding not only about ocean warming and water cycle reorganization (e.g., salinity changes), ocean eutrophication, and ocean deoxygenation, but also about changes in ocean chemistry. As an example of changes in the global ocean carbon cycle, consistent changes in surface seawater CO sub(2-)carbonate chemistry are documented by seven independent CO sub(2) time series that provide sustained ocean observations collected for periods from 15 to 30 years: (1) Iceland Sea, (2) Irminger Sea, (3) Bermuda Atlantic Time-series Study (BATS), (4) European Station for Time series in the Ocean at the Canary Islands (ESTOC), (5) CArbon Retention In A Colored Ocean sites in the North Atlantic (CARIACO), (6) Hawaii Ocean Time-series (HOT), and (7) Munida in the Pacific Ocean. These ocean time-series sites exhibit very consistent changes in surface ocean chemistry that reflect the impact of uptake of anthropogenic CO sub(2) and ocean acidification. The article discusses the long-term changes in dissolved inorganic carbon (DIC), salinity-normalized DIC, and surface seawater pCO sub(2) (partial pressure of CO sub(2)) due to the uptake of anthropogenic CO sub(2) and its impact on the ocean's buffering capacity. In addition, we evaluate changes in seawater chemistry that are due to ocean acidification and its impact on pH and saturation states for biogenic calcium carbonate minerals.

In a previous phylogenetic analysis of numerous species of the genus Munida and related genera from the West Pacific based on molecular and morphological data, the monophyly of this group with the exception of M. callista was established. Morphologically, M. callista is closely related to M. brucei, M. javieri, M. hystrix and M. plexaura showing morphological differences in the shape of the rostrum, the supraocular spines, and the ridges on the epistome with respect to the genus Munida. Moreover, the analysis of the mitochondrial genes 16S rRNA and COI showed an independent and monophyletic lineage from the genus Munida. Therefore a new genus, Babamunida, is proposed to accommodate these five species, based on morphological characters and molecular data.

Munida is the most diverse and cosmopolitan genus of the galatheid squat lobsters. The group has attracted much attention in recent years from both systematic and evolutionary perspectives, yet information on the biology, ecology and evolution of this genus is very limited. We investigated the genetic parentage of 2 North Atlantic species, M. rugosa and M. sarsi, sampled from the Clyde Sea on the west coast of Scotland. Microsatellite markers were used to establish the parental contribution from embryos of berried females (M. rugosa, n = 25 and M. sarsi, n = 5). The frequency of multiple paternity observed in both species (86% for M. rugosa and 100% for M. sarsi) is the highest ever reported for any marine crustaceans. Invariably more than 2 sires were involved in each case (minimum of 2 to 3 for M. rugosa and 4 for M. sarsi). Our findings indicate that multiple paternity is likely to be the norm in both species. Within most multiply sired broods, sire contribution was highly skewed towards a single male (66% of broods for M. rugosa and 100% for M. sarsi). Furthermore, embryos from different sires were randomly distributed across the female's brood patch. This is the first report of multiple paternity in galatheids. While a number of theories can account for the high incidence of multiple paternity in these species (e.g. convenience polyandry as a result of cryptic female choice, forced copulations, the influence of fishing pressures), at present it is not possible to disentangle their individual and/or combined effects.

We examined how a species inhabiting a latitudinal gradient, from warm oxygenated surface waters to cold oxygen-limited subsurface waters along the Eastern South Pacific (ESP) shelf, responds to latitudinal temperature shifts at low-oxygen isopleths. We combined temperature-oxygen sections from the World Ocean Database, historical records of pelagic/benthic Grimothea monodon occurrence across latitude, models with these data, and laboratory experiments assessing juveniles’ routine and postprandial metabolism under realistic temperature-oxygen conditions. The life habits (pelagic or benthic) of squat lobsters were related to temperature at the 2 mL O 2 L −1 oxygen isopleth. At temperatures > 15 °C near the upper oxygen minimum zone isopleth, mostly pelagic individuals were observed, suggesting restricted vertical migration. The physiological performance of juveniles (main migratory stage) was negatively affected by high temperature-hypoxia interaction. Routine metabolic rates decreased by 60% under hypoxia at 21 °C, and postprandial metabolism (as Specific Dynamic Action) was also strongly reduced under those conditions. Grimothea monodon can shift between pelagic and benthic habitats across a range of ESP conditions, maintaining the intergenerational ability to alternate habitats. This plasticity, expressed as vertical expansion or restriction, may help maintain or expand its latitudinal ranges, with natural food webs and fisheries adjusting to its availability as key prey item.

Expansion of oxygen deficient waters (hypoxia) in the northeast Pacific Ocean (NEP) will have marked impacts on marine life. The response of the resident communities will be a function of their ecophysiological constraints in low oxygen, although this remains untested in the NEP due to a lack of integrative studies. Here, we combine in situ surveys and lab-based respirometry experiments were conducted on three indicator species (spot prawn Pandalus platyceros, slender sole Lyopsetta exilis, squat lobster Munida quadrispina) of seasonally hypoxic systems in the NEP to test if metabolic constraints determine distributions and energy sequestration in a hypoxic setting. These experiments were integrated with a global review of critical oxygen levels ( O 2 crit ; lower threshold of aerobic metabolism) for crustaceans to determine if O 2 crit -based hypoxia thresholds are different among ocean basins. Our results show that species-specific differences in O 2 crit and standard metabolic rates (1) determine the lowest environmental oxygen ([O₂]env) at which in situ populations occur, (2) result in disproportionate shifts in distributions among co-occurring species during summer hypoxia expansion events, and (3) characterize shifts in megafaunal community respiration rates due to marked spatio-temporal variability in [O₂]env. Our results show that O 2 crit -based hypoxia thresholds are significantly lower in the East Pacific Ocean relative to other major ocean basins, which suggests that the physiological response of local fauna to deoxygenation can be determined by the natural variability and oxygen exposure in a region. In order to establish realistic predictions on the biological consequences of marine deoxygenation, we suggest integrating metabolism-based traits to calculate hypoxia thresholds for marine ecosystems.

The ecological niche is dynamic, since the position and width of the niche can vary at different spatial and temporal scales. We examined the trophic ecology of southeast Pacific humpback whales Megaptera novaeangliae in the Magellan Strait feeding area in 2011, 2012 and 2017, analyzing changes in diet and the width of the isotopic niche in relation to ontogeny and seasonality. The isotopic composition of carbon (δ13C) and nitrogen (δ15N) in whale skin and in putative prey species was analyzed. Bayesian mixing models were used to determine the diet, and the isotopic niche was estimated using the standard ellipse area. Differences were found between the diets of juveniles and adults; Fuegian sprat Sprattus fuegensis was consumed mostly by adult individuals. We found no differences in the diet or in the isotopic niche of humpback whales throughout the feeding season in all years. This study suggests that the differences in diet between age classes are influenced by the ability to find and capture prey, whereas seasonality does not influence the niche width of humpback whales in the Magellan Strait. Our results suggested that fluctuations in the abundance of prey populations could influence in the trophic niche dynamics of humpback whales in the Magellan Strait. In particular, a reduction in the availability of Fuegian sprat would mainly affect adult individuals, leading to a dietary switch and/or to an expansion of their feeding area.

Studies of genetic diversity and population genetic structure in deep-sea fauna mainly focus on vulnerable marine ecosystem (VME) indicator taxa, whilst relatively few studies have focussed on VME-associated taxa whose distributions are not exclusively limited to VMEs. Knowledge of genetic connectivity (gene flow) amongst populations of VME-associated taxa, such as squat lobsters, will contribute to ongoing management decision-making related to the protection of VMEs. To better understand the genetic diversity and genetic structure of squat lobster populations (Munida isos, M. endeavourae and M. gracilis) at different spatial scales (biogeographic provinces, regions, and geomorphic features) in the southwest Pacific Ocean, mitochondrial COI region and nuclear microsatellite markers were employed. Overall, the levels of genetic diversity were high for the COI region and moderate for the microsatellite loci across the three Munida species. AMOVA of COI variation revealed no significant genetic differentiation, whereas AMOVA of microsatellite variation revealed significant genetic differentiation amongst the three species, but at different spatial scales. Based on microsatellite variation, a range of analyses (Structure, PCoA, DAPC) provided some evidence of limited genetic differentiation at different spatial scales across the three species. Low to moderate levels of assignment success (~40–60%) based on microsatellite variation were achieved for the three Munida species, suggesting high levels of gene flow and possible panmixia. Nonetheless, for Munida isos, populations from the Tasmanian slope were genetically differentiated from all other populations and may act as source populations, whereas populations from the Kermadec Ridge region may be sink populations for all three Munida species. Our results highlight the need to consider gene flow at trans-national scales when managing anthropogenic impacts on VMEs. The results are discussed in the context of existing marine protected areas, which can contribute new information useful to the management of VMEs within the southwest Pacific Ocean.

In the sub-Antarctic waters of southern South America, two species that form conspicuous pelagic aggregations are considered both potential fishery resources and ecologically important: the Fuegian sprat Sprattus fuegensis and the squat lobster Munida gregaria. Here, we estimate spatio-temporal patterns of the relative abundance, distribution and potential areas of overlapping of M. gregaria and S. fuegensis in the Beagle Channel. Acoustic data were collected from 18 surveys conducted between 2009 and 2016 in the Beagle Channel. Our observations on the pelagic aggregations revealed that M. gregaria swarms and S. fuegensis schools occurred along the channel throughout the year. However, the occurrence of S. fuegensis was more evident in the inner part of the channel during the winter. There was a negative relationship between the relative abundance of squat lobsters and Fuegian sprats throughout the year. This interaction may result from spatial competition associated with resources, particularly in summer. The vertical distribution and morphology of aggregations of both species showed seasonal differences. Specifically, schools of Fuegian sprats were typically pelagic in summer, whereas in winter they were bigger and associated with the bottom layer. This change could be associated with a seasonal change in the oceanographic regime of the Beagle Channel. The information presented here is necessary to understand processes in a context of possible opening of fisheries targeting these two species that have key ecological roles in this sub-Antarctic ecosystem.

Intraspecific competition for food resources has the potential to be high for central-place foragers such as penguins and can result in spatial and dietary foraging niche segregation among individuals of the same species. We sampled adults, chicks, and juvenile individuals’ whole blood from three colonies of Magellanic penguins (Spheniscus magellanicus) from Tierra del Fuego along an inshore-offshore corridor. We analyzed the isotopic niche, the trophic position and the diet composition in penguins to investigate intraspecific trophic niche variation in relation to biological (age of individuals) and external factors (foraging habitats, colony location) using carbon (δ13C) and nitrogen (δ15N) stable isotope values. We found isotopic niche segregation between age classes within each colony. When comparing across colonies, only juvenile exhibited some degree of isotopic niche overlap among colonies. In addition, at all three colonies juveniles had the largest isotopic niches with relatively higher variation in δ13C values. All individuals consumed low trophic position (TP) prey items such as the pelagic form of Munida gregaria based on stable isotope mixing model results. Adults and juveniles incorporated high TP (silverside and nototheniids) prey items into their diets, except for juveniles from Martillo Island whose proportions mirror chicks’ values. These results denote that parents consumed different prey items for themselves than for their chicks. Intraspecific trophic niche partitioning between colonies showed a decreasing δ13C and δ15N values from the nearest inshore colony relative to the farther offshore colonies. Understanding within and between colonies foraging strategies are important to set up connectivity between populations, status of the different colonies, and to develop adequate conservation actions.

In early 2018, a large easterly storm hit the East Anglian coast of the UK, colloquially known as the ‘Beast from the East’, which also resulted in mass strandings of benthic organisms. There were subsequent instances of dogs consuming such organisms, leading to illness and, in some cases, fatalities. Epidemiological investigations identified paralytic shellfish toxins (PSTs) as the cause, with toxins present in a range of species and concentrations exceeding 14,000 µg STX eq./kg in the sunstar Crossaster papposus. This study sought to better elucidate the geographic spread of any toxicity and identify any key organisms of concern. During the summers of 2018 and 2019, various species of benthic invertebrates were collected from demersal trawl surveys conducted across a variety of locations in the North Sea. An analysis of the benthic epifauna using two independent PST testing methods identified a ‘hot spot’ of toxic organisms in the Southern Bight, with a mean toxicity of 449 µg STX eq./kg. PSTs were quantified in sea chervil (Alcyonidium diaphanum), the first known detection in the phylum bryozoan, as well as eleven other new vectors (>50 µg STX eq./kg), namely the opisthobranch Scaphander lignarius, the starfish Anseropoda placenta, Asterias rubens, Luidia ciliaris, Astropecten irregularis and Stichastrella rosea, the brittlestar Ophiura ophiura, the crustaceans Atelecyclus rotundatus and Munida rugosa, the sea mouse Aphrodita aculeata, and the sea urchin Psammechinus miliaris. The two species that showed consistently high PST concentrations were C. papposus and A. diaphanum. Two toxic profiles were identified, with one dominated by dcSTX (decarbamoylsaxitoxin) associated with the majority of samples across the whole sampling region. The second profile occurred only in North-Eastern England and consisted of mostly STX (Saxitoxin) and GTX2 (gonyautoxin 2). Consequently, this study highlights widespread and variable levels of PSTs in the marine benthos, together with the first evidence for toxicity in a large number of new species. These findings highlight impacts to ‘One Health’, with the unexpected sources of toxins potentially creating risks to animal, human and environmental health, with further work required to assess the severity and geographical/temporal extent of these impacts.