Effectiveness of a deep-sea cold-water coral Marine Protected Area, following eight years of fisheries closure

Pressure on deep-sea ecosystems continues to increase as anthropogenic activities move into ever deeper waters. To mitigate impacts on vulnerable habitats, various conservation measures exist, such as the designation of Marine Protected Areas (MPAs). So far, however, little evidence is available about their effectiveness. This paper presents a unique follow-up study assessing the status and recovery of a deep-sea fisheries closure and MPA at ~1000 m water depth in the NE Atlantic, eight years after designation. The Darwin Mounds cold-water coral ecosystem was discovered in 1998, and closed to all bottom contact fisheries, especially trawling, in 2003. Our repeat survey in 2011 used both high-resolution sidescan sonar data collected by Autonomous Underwater Vehicle (AUV) and video footage from a Remotely Operated Vehicle (ROV) to evaluate recovery. The results demonstrate that (1) protection was successful and fishing impact was largely avoided in the Western Darwin Mounds, which contained similar proportions of live cold-water coral occurrence in 2011 as observed in 1998-2000; however (2) the Eastern Darwin Mounds suffered severe damage pre-closure, and by 2011 showed no coral recolonisation and very little regrowth. These results are further evidence for the low resilience and slow recovery potential of deep-sea ecosystems, and underline once again the importance of the precautionary principle in deep-sea conservation

25.1 High Efficiency Monolithic Perovskite Silicon Tandem Solar Cell with a High Bandgap Perovskite Absorber

Monolithic perovskite silicon tandem solar cells can overcome the theoretical efficiency limit of silicon solar cells. This requires an optimum bandgap, high quantum efficiency, and high stability of the perovskite. Herein, a silicon heterojunction bottom cell is combined with a perovskite top cell, with an optimum bandgap of 1.68 amp; 8201;eV in planar p i n tandem configuration. A methylammonium free FA0.75Cs0.25Pb I0.8Br0.2 3 perovskite with high Cs content is investigated for improved stability. A 10 molarity increase to 1.1 amp; 8201;m of the perovskite precursor solution results in amp; 8776;75 amp; 8201;nm thicker absorber layers and 0.7 amp; 8201;mA amp; 8201;cm amp; 8722;2 higher short circuit current density. With the optimized absorber, tandem devices reach a high fill factor of 80 and up to 25.1 certified efficiency. The unencapsulated tandem device shows an efficiency improvement of 2.3 absolute over 5 amp; 8201;months, showing the robustness of the absorber against degradation. Moreover, a photoluminescence quantum yield analysis reveals that with adapted charge transport materials and surface passivation, along with improved antireflection measures, the high bandgap perovskite absorber has the potential for 30 tandem efficiency in the near futur

Temporal changes (1989–1999) in deep-sea metazoan meiofaunal assemblages on the Porcupine Abyssal Plain, NE Atlantic

Trends among major metazoan meiofaunal taxa were investigated based on 56 deployments of a multicorer at 10 time points over a period of 11 years (1989–1999) at the Porcupine Abyssal Plain Sustained Observatory site (PAP-SO: 48°50?N 16°30?W, 4850 m depth). This area is characterised by a strong seasonality in the deposition of organic matter to the seafloor and by the massive increase in the density of holothurian species since 1996, the so-called ‘Amperima event’. Total meiofaunal densities ranged from 346 to 1074 ind.×10 cm?2 and showed a significant increase with time when time was represented by cruises, years and the ‘Amperima period’ (1996–1999) vs. the pre-Amperima period (1989–1994). This pattern was driven mainly by the nematodes, which were the dominant taxon (not, vert, similar90% of total abundance). The third most abundant group, the polychaetes, also increased significantly in abundance over the time series, while the ostracods showed a significant decrease. Most other taxa, including the second-ranked group, the copepods (harpacticoids and nauplii), did not exhibit significant temporal changes in abundance. Ordination of taxon composition showed a shift from the pre-Amperima to the Amperima periods, a trend supported by the significant correlation between the x-ordinate and time. The majority (52–75%) of meiofaunal animals inhabited the top 2 cm of the 5 cm sediment cores analysed. There were significant increases in the proportion of total meiofauna, nematodes and copepods (but not polychaetes) inhabiting the 0–1 cm layer over time (represented by cruises) and between the pre-Amperima and Amperima periods in the case of copepods and polychaetes. During the intensively sampled period (1996–1997), there were indications of seasonal changes in the vertical distribution patterns of total meiofauna and nematodes within the sediment. We discuss the potential link between temporal variations in organic matter flux to the seafloor and meiofaunal populations, considering both qualitative and quantitative changes in fluxes and how they may be linked to climate variations

A large testate protist, Gromia sphaerica sp.nov. (Order Filosea), from the bathyal Arabian Sea

The deep ocean provides a habitat for several large testate protistan taxa, e.g., xenophyophores and komokiaceans. However, testate amoebae (orders Lobosea and Filosea) have never been reliably reported from below 270 m depth. Here we describe large spherical protists, up to almost 40 mm diameter, recovered in box core, multicore, and epibenthic sledge samples taken on the continental slope off Oman (NW Arabian Sea) during RRS Discovery Cruise 211. Specimens consist of an organic envelope, with numerous tiny apertures, enclosing a mass of fine waste pellets (stercomata). On the basis of its wall ultrastructure (revealed by high-voltage transmission electron microscopy), this organism is identified as a member of the filosean genus Gromia. It is described herein as Gromia sphaerica sp. nov. The wall is layered and includes the ‘honeycomb membrane', a structure that is unique to this genus. The new species is the first gromiid to be reported from the deep sea. It lives between about 1200 and 1630 m below the main oxygen minimum zone, in an area where bottom-water oxygen concentrations are around 0.47 ml l?1. The new gromiid species is clearly visible in bottom photographs taken at 1273 m (2.7 individuals m?2), 1318 m (2.7 indiv. m?2), 1624 m (17.3 indiv. m?2) and 1633 m (76.5 indiv. m?2). They lie partly embedded in the seafloor and are sometimes grouped in twos and threes. Specimens are typically surrounded by an apron of lighter-coloured sediment, possibly resulting from their feeding activities. Where they lie in very close proximity, the apron around one specimen typically obscures adjacent tests

Decadal-scale changes in shallow-infaunal foraminiferal assemblages at the Porcupine Abyssal Plain, NE Atlantic

Trends in the abundance, diversity and taxonomic composition of ‘live’ (rose Bengal stained) foraminiferal assemblages (0-1 cm layer, >63-?m fraction) were analysed in replicate multiple corer samples collected at the Porcupine Abyssal Plain (48° 50’ N, 16° 30’ W, 4850 m water depth) over a 13-yr period (1989-2002). Total densities were significantly higher in 1996-2002 compared to 1989-1994, a change coincident with a spectacular rise in the density of the holothurian Amperima. However, total densities exhibited no significant relation to seasons or any significant correlation with modelled organic matter flux, the North Atlantic Oscillation (NAO) index, Amperima densities, or megafaunal assemblage composition. Over the same period, species richness and diversity measures decreased and dominance increased, although not significantly. Multivariate analyses revealed three assemblages represented by samples collected in 1989-1994, 1996-July 1997 and October 1997-October 2002. These reflected temporal changes in the densities of higher taxa and species. Trochamminaceans, notably a small undescribed species, increased from 5-9% (1989-1994) to 29-40% (1996-2002) of the assemblage with a corresponding rise in absolute abundance. Species of Hormosinacea and Lagenammina also tended to increase in density from 1996/1997 onwards. Rotaliids, dominated by Alabaminella weddellensis and Epistominella exigua, showed a bimodal distribution over time with peak densities in May 1991 (32%) and September 1998 (28%) and lowest densities in 1996-1997. Responses by these species to seasonal phytodetritus inputs probably explain the relative abundance of E. exigua, and to a lesser extent A. weddellensis, in 1989 and 1991 when phytodetritus was present. A qualitative change in the phytodetrital food, repackaging of food by megafauna, increased megafaunal disturbance of the surficial sediment, or a combination of these factors, are possible explanations for the dominance of trochamminaceans from 1996 onwards. The miliolid Quinqueloculina sp. was virtually absent in multicore samples (0-1 cm, >63-?m fraction) from 1989-1994, peaked in September 1996 (22%) when degraded phytodetritus was present on core surfaces, was less common in March 1997, and thereafter was relatively uncommon. However, horizontally sliced box-core samples (0-5 cm, >250-?m fraction) revealed that large specimens were more abundant in March 1997, and also were concentrated in deeper sediment layers, than in September 1996. We suggest that Quinqueloculina sp. migrated to the sediment surface in response to a 1996 flux event, grew and reproduced, before migrating back into deeper layers as the phytodetrital food became exhausted. Overall, the abyssal time-series revealed decadal-scale changes among shallow-infaunal foraminifera, more or less coincident with changes in the megafauna, as well as indications of shorter-term events related to seasonally-pulsed phytodetrital inputs

Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

The Pakistan Margin is characterised by a strong mid-water oxygen minimum zone (OMZ) that intercepts the seabed at bathyal depths (150–1300 m). We investigated whether faunal abundance and diversity trends were similar among protists (foraminiferans and gromiids), metazoan macrofauna and megafauna along a transect (140–1850 m water depth) across the OMZ during the 2003 intermonsoon (March–May) and late/post-monsoon (August–October) seasons. All groups exhibited some drop in abundance in the OMZ core (250–500 m water depth; O2: 0.10–0.13 mL L−1=4.46–5.80 μM) but to differing degrees. Densities of foraminiferans >63 μm were slightly depressed at 300 m, peaked at 738 m, and were much lower at deeper stations. Foraminiferans >300 μm were the overwhelmingly dominant macrofaunal organisms in the OMZ core. Macrofaunal metazoans reached maximum densities at 140 m depth, with additional peaks at 850, 940 and 1850 m where foraminiferans were less abundant. The polychaete Linopherus sp. was responsible for a macrofaunal biomass peak at 950 m. Apart from large swimming animals (fish and natant decapods), metazoan megafauna were absent between 300 and 900 m (O2 0.2 mL L−1=8.92 μM). The progressively deeper abundance peaks for foraminiferans (>63 μm), Linopherus sp. and ophiuroids probably represent lower OMZ boundary edge effects and suggest a link between body size and tolerance of hypoxia. Macro- and megafaunal organisms collected between 800 and 1100 m were dominated by a succession of different taxa, indicating that the lower part of the OMZ is also a region of rapid faunal change. Species diversity was depressed in all groups in the OMZ core, but this was much more pronounced for macrofauna and megafauna than for foraminiferans. Oxygen levels strongly influenced the taxonomic composition of all faunal groups. Calcareous foraminiferans dominated the seasonally and permanently hypoxic sites (136–300 m); agglutinated foraminiferans were relatively more abundant at deeper stations where oxygen concentrations were >0.13 mL L−1(=5.80 μM). Polychaetes were the main macrofaunal taxon within the OMZ; calcareous macrofauna and megafauna (molluscs and echinoderms) were rare or absent where oxygen levels were lowest. The rarity of larger animals between 300 and 700 m on the Pakistan Margin, compared with the abundant macrofauna in the OMZ core off Oman, is the most notable contrast between the two sides of the Arabian Sea. This difference probably reflects the slightly higher oxygen levels and better food quality on the western side