Seagrass meadows are complex social-ecological systems. Understanding seagrass meadows demands a fresh approach integrating “the human dimension”. Citizen science is widely acknowledged for providing significant contributions to science, education, society and policy. Although the take up of citizen science in the marine environment has been slow, the need for such methods to fill vast information gaps is arguably great. Seagrass meadows are easy to access and provide an example of where citizen science is expanding. Technological developments have been pivotal to this, providing new opportunities for citizens to engage with seagrass. The increasing use of online tools has created opportunities to collect and submit as well as help process and analyse data. Citizen science has helped researchers integrate scientific and local knowledge and engage communities to implement conservation measures. Here we use a selection of examples to demonstrate how citizen science can secure a future for seagrass.

Natural marine snow (NMS) is defined as the “shower” of particle aggregates formed by processes that occur in the world's oceans, consisting of macroscopic aggregates of detritus, living organisms and inorganic matter. Recent studies from the Deepwater Horizon oil spill suggest that marine snow is also formed in association with oil spills and was an important factor for the transport of oil to the seabed. This review summarizes the research and literature on MS, mainly from the DWH oil spill, with a focus on the relation between the use of oil spill dispersants and the formation and fate of oil-related marine snow (ORMS). Studies are still required to determine ORMS processes at oil concentrations as relevant as possible for chemically dispersed oil.

Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide ⁴⁰K and the natural-series indicator radionuclides ²²⁶Ra and ²³²Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of ²²⁶Ra, ²³²Th and ⁴⁰K from 451±9 to 2411±65Bqkg⁻¹ (mean of 1478Bqkg⁻¹); 232±4 to 1272±35Bqkg⁻¹ (mean of 718Bqkg⁻¹) and 61±6 to 136±7Bqkg⁻¹ (mean of 103Bqkg⁻¹) respectively. Conversely, in white sands the respective values for ²²⁶Ra and ²³²Th were appreciably lower, at 8.3±0.5 to 13.7±1.4Bqkg⁻¹ (mean of 9.8Bqkg⁻¹) and 4.5±0.7 to 9.4±1.0Bqkg⁻¹ (mean of 5.9Bqkg⁻¹); ⁴⁰K activities differed insubstantially from that in black sands, at 85±4 to 133±7Bqkg⁻¹ with a mean of 102Bqkg⁻¹. The mean activity concentrations of ²²⁶Ra and ²³²Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated ²²⁶Ra and ²³²Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources.

Coral communities in Tolo Harbour and Channel, northeastern Hong Kong, suffered from tremendous degradations in 1980s due to excessive sewage pollutions. This study examined changes in coral community structures over the last 30 years including period before, at the height of and after implementation of abatement measures of pollution impacts. Signs of coral degradations finally stopped in inner harbour and some corals started to reappear, likely due to sewage export scheme since 1998. Yet, the coral cover remained very low (<2%) in 2012. Natural recovery is limited by very low coral recruitment success other than that of Oulastrea crispata. The outer coral communities, which suffered least in 1980s, continued to decline, possibly due to new biological disturbances like sea urchin predation and bioerosion. This long-term study clearly revealed how coral communities could so easily be destroyed and yet natural recovery could be so difficult and unlikely.

This study provides the first quantification of plastic ingestion in the Tristram's Storm-petrel (Oceanodroma tristrami) in over 20 years. We found 100% plastic incidence in 57 chicks collected opportunistically over four breeding seasons (2007, 2010, 2011, 2012), with the mass of ingested plastic per individual ranging from 0.1 to 2.8 g (≤3.3% adult mass). While plastic occurred in every bird we examined, the proventriculus contained significantly more plastic, more fragments, and larger fragments than the gizzard. Most of the ingested plastic (97.5% by mass) consisted of fragments, ranging in length from 0.4 to 11.6 mm and ranging in surface area from 0.07 to 45.21 mm2. While fragments were ubiquitous, occurring in every proventriculus and gizzard we analyzed, Tristram's Storm-petrels also ingested foam, line and sheets. Digital analysis of 1425 ingested plastic fragments documented a wide range of colors, involving shades of white, yellow, orange, red, blue, green, and black.

The fabrication of the materials with special wettability being capable of removing oil layer on water surface and oil droplets in oil-in-water emulsion is an important issue for water pollution. So far, it still remains challenging to explore a simple, facile, environmentally friendly approach for achieving this goal. Herein, inspired by the adhesion of marine mussels, the polydopamine (PDA) coating with hierarchical structure was directly fabricated onto the surface of melamine (MF) sponge by facile self-polymerization in dopamine solution. Then, a superhydrophobic and superoleophilic sponge was successfully obtained after the modification by dodecanethiol (DDT) at ambient temperature. The as-prepared sponge can selectively separate a series of oil droplets in oil-in-water emulsion with high efficiency (transparency: 76.6–93.8%) and absorb various oils or organic solvents up to 45.2–98.6 times of its own weight. Moreover, in conjunction with a vacuum system, great amounts of oils up to 20 times its own weight can be effectively separated from water surface within 1s by the sponge. Due to low cost, simple process, and easy accessibility, the as-prepared sponge has potential applications in oil-in-water emulsion separation and oil spill cleanup.

In order to investigate the current distribution of metal concentrations in surface marine sediments of the southern coast of Sfax (Tunisia), thirty-nine samples were collected in the vicinity of a mixed industrial and domestic wastewater effluent discharge. In comparison with the threshold effect level and probable effect level, the majority of metals had high ecological and biological risks. Enrichment factor and geoaccumulation Index showed that the majority of sediments are unpolluted by As, Ni and Pb, moderately polluted by Cr and Cu and moderately to strongly polluted by P, Y, Zn. Besides, all sites are extremely polluted by Cd. Principal component analysis indicates that As, Cu and Ni were mainly from lithogenic sources, whereas Cd, Cr, F, P, Pb, Y and Zn were mainly derived from anthropogenic source. Findings of this research can be used as suitable reference for future studies and environmental management plans in the region.

δ15N values of coastal biota have been used as indicators of land-derived N-loads and sources to estuarine systems and should respond predictably to differences in nitrogen and be sensitive to changes in nitrogen, preferably at the low end of eutrophication. We evaluated Spartina alterniflora as an indicator species of N-loads and sources of δ15N throughout the growing season, and compared the average δ15N to estuarine nitrogen loads and sources for several estuaries receiving different watershed N-loads. δ15N of S. alterniflora differed among estuaries, and these differences were maintained even as δ15N declined during the end of the growing season. δ15N values increased with increasing nitrogen loads to the subestuaries and with increasing percent wastewater-derived nitrogen load. The response of δ15N of S. alterniflora to increased N loads was greater at low N-loads, and decreased as N-loads increased, suggesting that S. alterniflora is a good indicator of incipient nitrogen load.

The availability of marine habitats maps remains limited due to difficulty and cost of working at sea. Reduced light penetration in the water hampers the use of optical imagery, and acoustic methods require extensive sea-truth activities. Predictive spatial modelling may offer an alternative to produce benthic habitat maps based on complete acoustic coverage of the seafloor together with a comparatively low number of sea truths. This approach was applied to the coralligenous reefs of the Marine Protected Area of Tavolara - Punta Coda Cavallo (NE Sardinia, Italy). Fuzzy clustering, applied to a set of observations made by scuba diving and used as sea truth, allowed recognising five coralligenous habitats, all but one existing within EUNIS (European Nature Information System) types. Variable importance plots showed that the distribution of habitats was driven by distance from coast, depth, and lithotype, and allowed mapping their distribution over the MPA. Congruence between observed and predicted distributions and accuracy of the classification was high. Results allowed calculating the occurrence of the distinct coralligenous habitats in zones with different protection level. The five habitats are unequally protected since the protection regime was established when detailed marine habitat maps were not available. A SWOT (Strengths-Weaknesses-Opportunities-Threats) analysis was performed to identify critical points and potentialities of the method. The method developed proved to be reliable and the results obtained will be useful when modulating on-going and future management actions in the studied area and in other Mediterranean MPAs to develop conservation efforts at basin scale.

Ballast water is essential for maintaining the balance and integrity of a ship. However, exchanging ballast water resulted in discharging water of different origins in vessel recipient ports, and this may have caused ecosystem disturbance or aquatic pollution. The ballast water management (BWM) system is essential for the purification and disinfection of the ballast water that is taken up. Because current BWM systems widely use biocides for the treatment of aquatic organisms, the biocides may result in unintended toxicity of the discharged ballast water. In this study, we suggested thymol and carvacrol as chemical biocides for BWM systems and investigated their effectiveness using Artemia salina and Escherichia coli. Thymol and carvacrol showed biocidal effects in our study. A combination of these substances showed a synergistic increase in the biocidal effects. Moreover, carvacrol naturally degrades after disinfection, which indicates that natural substances may be promising candidates to increase the efficacy and reduce unwanted side effects of the BWM system.