Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of 12 seagrass genera. We document four classic trajectories of degradation and recovery for seagrass ecosystems, illustrated with examples from around the world. Recovery can be rapid once conditions improve, but seagrass absence at landscape scales may persist for many decades, perpetuated by feedbacks and/or lack of seed or plant propagules to initiate recovery. It can be difficult to distinguish between slow recovery, recalcitrant degradation, and the need for a window of opportunity to trigger recovery. We propose a framework synthesizing how the spatial and temporal scales of both disturbance and seagrass response affect ecosystem trajectory and hence resilience.

Bryozoa is a phylum of aquatic invertebrates widely distributed around the world, including harbor areas. They have association to artificial structures as main mechanism of dispersal, including ships, which facilitates their introduction to new environments. The detection of exotic species is important to prevent new introductions and to propose management strategies of marine areas. Thus, after analyzing and discussing local and global criteria of exotic species, an account of exotic bryozoans from Brazil is presented, including 12 classified as exotic (six established and six detected) and 17 classified as potentially exotic (cryptogenic). Three species have been reported causing economic or environmental impacts worldwide. Of those, Membraniporopsis tubigera is known to cause economic impacts on the Brazilian coast. Hull fouling is the main dispersal mechanism for exotic bryozoans. The lacking of reliable data did not allow inferring on the exotic status on some fouling bryozoan species in Brazil.

With INDESO, Indonesia has implemented a system for the monitoring and management of its tuna resources. Despite increasing catch, very few is known about the dynamics and real abundance of tuna species in the Indonesian waters and adjacent oceanic regions. The SEAPODYM model was implemented in an operational chain of production for the Indonesian region to simulate tuna spatial dynamics in realtime. This challenging objective imposed developing a global scale model at coarse resolution to provide initial and boundaries conditions of the regional model. A parameter optimization approach was used to provide the best solution fitting several hundreds of thousand catch observations, over a long historical simulation at coarse resolution. Then downscaling method and regional modelling at high resolution (1/12°x day) were validated to produce realtime and forecast on a weekly basis. The architecture of this application, the approach for its parameterization and some key results are presented and discussed.

In this paper, a rapid, selective and effective technique, pipette-tip solid phase extraction based on molecularly imprinted polymer, was used for extraction and pre-concentration of methyl red (MR) prior to its determination by spectrophotometer. Variables influencing extraction efficiency including type and volume of eluent solvent, sample volume, number of cycles of extraction and elution, amount of sorbent and pH of the sample solution were optimized with two methods of one-variable-at-a-time and response surface methodology (RSM). For RSM optimization, seven factors in three-levels were utilized for Box-Behnken experimental design. Under optimum conditions, a linear calibration graph in the range of 3.0–300.0 μg L−1 for MR was resulted. The limit of detection of proposed method was 0.50 μg L−1 for MR. Finally, the investigated method was used for the determination of MR in seawater and the mean recoveries were calculated to be 84.0–98.0% with mean RSD of 2.5–6.7%.

The 240Pu/239Pu atom ratio and 239+240Pu activity of seawater in the East China Sea (ECS) was measured in order to examine the Pu sources and elaborate Pu scavenging process. High 240Pu/239Pu atom ratios (0.187–0.243, average = 0.221 ± 0.017) in the surface water and water column were observed during 2011, implying of non-global fallout Pu sources. The distribution of 240Pu/239Pu atom ratio in the ECS was in agreement with the introduction pathway of the Kuroshio, showing a decreasing trend away from the outer shelf. An even higher 240Pu/239Pu atom ratios (0.243–0.263, average = 0.253 ± 0.007) were observed in the Kuroshio, indicating the non-global fallout Pu signal from the Pacific Proving Grounds (PPG). Using a two end-member mixing model, the Pu source from the PPG contribution was calculated to be 36 ± 9% in the ECS seawater. The 239+240Pu activities of surface seawater were in the range of 2.00–2.95 mBq m−3 in the ECS. The spatial distribution of 239+240Pu activity in the surface seawater showed an increasing trend from the outer shelf to the nearshore. Moreover, 239+240Pu inventory of water column at the station DH23 in the ECS was calculated to be ~0.29 Bq m−2, which was 1–3 orders of magnitude lower than the estimates of sediment cores in the ECS shelf (9–407 Bq m−2). Such differences were determined by the high degree Pu scavenging efficiency in the ECS and high Pu input carried by terrestrial sediments from the Yangtze River. Finally, both 240Pu/239Pu atom ratios and 239+240Pu activities were identical before and after the Fukushima nuclear accident (FNA), suggesting that the impact of the FNA on the ECS was negligible.

Like fishing, natural regime shifts and human-induced environmental changes are often equally important factors in driving fish stock declines. In the Northwestern Arabian Gulf, many fish stocks are declining, raising questions about the reduction in the flow of Tigris-Euphrates rivers. Here we investigate the relationship between Tigris-Euphrates river flow and the estimated recruitment patterns from assessment models. We found a positive correlation between the estimated finfish recruitment trends and the flow of Tigris-Euphrates rivers. Additionally, the assessment model showed remarkably weak compensation ratio, likely indicating a reduction in the productivity of nursery area of two finfish stocks but not in that of the crustacean stock. Our investigation would be very critical in providing guidelines to the government agencies in the Northwestern Arabian Gulf as well as countries of Tigris-Euphrates basins: to consider the impacts associated with reductions in Tigris-Euphrates river flows on the ecosystem services of the region.

Hokkaido, the northernmost of the main islands of Japan, is surrounded by the North Pacific Ocean, the Japan Sea and the Okhotsk Sea, and three independent stocks of Pacific cod are thought to inhabit those three areas. The Fukushima Dai-ichi Nuclear Power Plant (FDNPP), which is located in the north of Honshu, the main island of Japan, was disputed in 2011. Most of the radiocesium from the FDNPP was released into the western North Pacific Ocean, and the biota in those areas were considerably contaminated soon after the FDNPP accident. We analyzed radiocesium in Pacific cod caught around Hokkaido between 2011 and 2015. The radiocesium was predominantly detected in the cod caught in the North Pacific Ocean, and not in those caught the Japan Sea and the Okhotsk Sea. These results suggest that the cod caught in the Pacific Ocean around Hokkaido moved through the contaminated area off the FDNPP.

Offshore drilling operations result in the generation of drill cuttings and localized smothering of the benthic habitats. This study explores bacterial community changes in the in the upper layers of the seafloor resulting from an exploratory drilling operation at 1400m water depth on the Barents Sea continental slope. Significant restructurings of the sediment microbiota were restricted to the sampling sites notably affected by the drilling waste discharge, i.e. at 30m and 50m distances from the drilling location, and to the upper 2cm of the seafloor. Three bacterial groups, the orders Clostridiales and Desulfuromonadales and the class Mollicutes, were almost exclusively confined to the upper two centimeters at 30m distance, thereby corroborating an observed increase in anaerobicity inflicted by the drilling waste deposition. The potential of these phylogenetic groups as microbial bioindicators of the spatial extent and persistence of drilling waste discharge should be further explored.

Microlitter (0.5–5mm) concentrations in water column (depth range from 0 to 217.5m) of the main Baltic Proper basins are reported. In total, 95 water samples collected in 6 research cruises in 2015–2016 in the Bornholm, Gdansk, and Gotland basins were analysed. Water from 10- and 30-litre Niskin bathometers was filtered through the 174μm filters, and the filtrate was examined under optical microscope (40×). The bulk mean concentration was 0.40±0.58 items per litre, with fibres making 77% of them. Other types of particles are the paint flakes (19%) and fragments (4%); no microbeads or pellets. The highest concentrations are found in the near-bottom samples from the coastal zone (2.2–2.7 items per litre max) and from near-surface waters (0.5m) in the Bornholm basin (5 samples, 1.6–2.5 items per litre). Distribution of particles over depths, types, and geographical regions is presented.

Cadmium is present in agricultural soil composition and is assimilated by plants. The mussel industry generates large volumes of calcareous valves as a byproduct of processing in factories. This solid waste is ground, stored and disposed of in the form of agricultural supplies near production areas in almost all regions of the world. Cd content was recorded in these calcareous substrate by-products of industrial processes. In this study, mussel shells were investigated in three areas in the sea of Chile; two areas with high aquaculture activity and one in a non-production area. Mass Spectrometry was used for [Cd] readings. There are no significant differences (p=0.92) in [Cd] between the studied areas. Additionally, the [Cd] observed in valves was also similar relative to different depths. The low [Cd] observed in valves (~0.014±0.0049mgCdkg−1 dry) suggests the potential use of this industrial byproduct in agricultural applications.