The prevalence of antimicrobial resistance reduces the effectiveness of antimicrobial drugs in preventing and treating infectious diseases caused by pathogenic organisms, such as bacteria, fungi, and viruses. Because of the burgeoning growth of microbes with antimicrobial-resistant traits, there is a dire need to identify and develop novel and effective antimicrobial agents to treat infections from antimicrobial-resistant strains. The marine environment is rich in ecological biodiversity and can be regarded as an untapped resource for prospecting novel bioactive compounds. Therefore, exploring the marine environment for antimicrobial agents plays a significant role in drug development and biomedical research. Several earlier scientific investigations have proven that bacterial diversity in the marine environment represents an emerging source of structurally unique and novel antimicrobial agents. There are several reports on marine bacterial secondary metabolites, and many are pharmacologically significant and have enormous promise for developing effective antimicrobial drugs to combat microbial infections in drug-resistant pathogens. In this review, we attempt to summarize published articles from the last twenty-five years (1996-2020) on antimicrobial secondary metabolites from marine bacteria evolved in marine environments, such as marine sediment, water, fauna, and flora.

As IUCN critically vulnerable species,the Indo-Pacific humpback dolphins (Sousa chinensis) have attracted great public attention in recent years. The threats of human disturbance and environmental pollution to this population have been documented extensively. However, research on the sensitivity of this species to climate change is lacking. To understand the effect of climate change on the potential distribution of Sousa chinensis, we developed a weighted ensemble model based on 82 occurrence records and six predictor variables (e.g., ocean depth, distance to shore, mean temperature, salinity, ice thickness, and current velocity). According to the true skill statistic (TSS) and the area under the receiver operating characteristic curve (AUC), our ensemble model presented higher prediction precision than most of the single-algorithm models. It also indicated that ocean depth and distance to shore were the most important predictors in shaping the distribution patterns. The projections for the 2050s and 2100s from our ensemble model indicated a severe adverse impact of climate change on the Sousa chinensis habitat. Over 75% and 80% of the suitable habitat in the present day will be lost in all representative concentration pathway emission scenarios (RCPS) in the 2050s and 2100s, respectively. With the increased numbers of records of stranding and deaths of Sousa chinensis in recent years, strict management regulations and conservation plans are urgent to safeguard the current suitable habitats. Due to habitat contraction and poleward shift in the future, adaptive management strategies, including designing new reserves and adjusting the location and range of reserves according to the geographical distribution of Sousa chinensis, should be formulated to minimize the impacts of climate change on this species.

There is an increasing awareness of how damaging pollutants in the marine environment can be, however information on the effects of metal engineered nanoparticles (ENPs) on marine biota is still insufficient, despite an exponential rising in related publications in recent years. In order to provide an integrated insight on the present state of the art on metal ENP-related ecotoxicology studies on marine fauna, this review aimed to: (i) highlight the means of toxicity of metal ENPs in the marine environment, (ii) identify the principal biotic and abiotic factors that may alter metal ENP toxicity, and (iii) analyse and categorize results of these studies, including accumulation, molecular and histological biomarkers, genotoxicity and behavioural changes. Data retrieved from Scopus yielded 134 studies that met pre-established criteria. Most often, the target ENPs were titanium, zinc, copper or silver, and most studies (61.2%) focused on the phylum Mollusca. The degree of toxicity of metal ENPs was often dependent on the concentrations tested, length of exposure and the type of tissue sampled. Effects from simple tissue accumulation to DNA damage or behavioural alterations were identified, even when concentrations below environmentally available levels were used. It is proposed that other phyla besides the traditional Mollusca (and within it Bivalvia) should be used more often in this kind of studies, that exact pathways of toxicity be further explored, and lastly that co-stressors be used in order to best mimic conditions observed in nature. In this review, the current knowledge on engineered metal nanoparticles and their effects on marine fauna was summarized, highlighting present knowledge gaps. Guidelines for future studies focusing on under-developed subjects in ENP toxicology are also briefly provided.

Sandy sediment and its infauna were annually sampled along the shallow waters of the Israeli coast during the 2005-2016 period, as a part of the Israeli National Environmental Program framework, aiming to detect anthropogenic interference in that province by monitoring changes in the species composition, abundance, and diversity of the infaunal communities and in accompanied abiotic parameters: the levels of total organic carbon and a series of heavy metals and the site-specific grain size distribution. The > 250-μm fraction of the fauna was segregated from the sampled sediment and was identified to species or higher taxonomic level. Three spatial biotopes were determined based on their unique faunal composition, Haifa Bay, Haifa harbor, and the southern coast. Species homogeneity among samples of each biotope was evaluated. Temporal and spatial changes of the species composition, abundance, and diversity were calculated for each biotope, mostly revealing random annual fluctuations. Only two minor temporal trends were observed: two spatially identical and temporally different faunal communities in the southern coast biotope, distinguishing the 2005-2007 and 2008-2016 periods, and a slight increase in the number of species across time in the two Haifa Bay provinces. Total organic carbon was highly correlated to the faunal composition with the highest organic carbon levels in the Haifa harbor biotope. The biotopes\' mutually occurring abundant species were sufficient to determine biotope borders and the contribution of intermittently sampled rare species, including the zoogeographically Indo-Pacific originated ones was feeble, important only to identify species migration and faunistics. Practically, three sampling sites along the Israeli shallow soft substrate, corresponding to the defined spatial biotopes, are sufficient to monitor the effect of environmental changes. Seasonal sampling twice a year is recommended as well as more accurate species identification using molecular taxonomy.

Chlordecone is an organochlorine pesticide, used in the Lesser Antilles from 1972 to 1993 to fight against a banana weevil. That molecule is very persistent in the natural environment and ends up in the sea with runoff waters. The objective of the present study is to evaluate the level of contamination in several trophic groups of marine animals according to their distance from the source of pollution. Samples of suspended matter, macroalgae, herbivorous fishes, detrivorous crustaceans, zooplanktivorous fishes, first- and second-order of carnivorous fishes, and piscivorous fishes have been collected in two sites, located downstream the contaminated sites (Goyave and Petit-Bourg), in three marine habitats (coastal mangroves, seagrass beds located 1.5 km from the shoreline, and coral reefs at 3 km offshore). Animals collected in mangroves were the most contaminated (mean concentrations 193 μg kg-1 in Goyave and 213 μg kg-1 in Petit-Bourg). Samples from seagrass beds presented intermediate concentrations of chlordecone (85 μg kg-1 in Goyave and 107 μg kg-1 in Petit-Bourg). Finally, samples from coral reefs were the less contaminated (71 μg kg-1 in Goyave and 74 μg kg-1 in Petit-Bourg). Reef samples, collected 3 km offshore, were two to three times less contaminated than those collected in mangroves.

Blood parasites are generally uncommon in seabirds, and knowledge on their epidemiology is further limited by the fact that they often inhabit remote locations that are logistically difficult or expensive to study. We present a long term data set of blood smear examinations of 1909 seabirds belonging to 27 species that were admitted to a rehabilitation centre in Cape Town (Western Cape, South Africa) between 2001 and 2013. Blood parasites were detected in 59% of species (16/27) and 29% of individuals examined (551/1909). The following blood parasites were recorded: Babesia ugwidiensis, Babesia peircei, Babesia sp., Plasmodium sp., Leucocytozoon ugwidi, Hepatozoon albatrossi, Haemoproteus skuae and Spirochaetales. Several of the records are novel host-parasite associations, demonstrating the potential of rehabilitation centres for parasite and disease surveillance, particularly for species infrequently sampled from which no host-specific parasites have been described.

The underwater sound produced during construction of the Port of Rotterdam harbor extension (Maasvlakte 2) was measured, with emphasis on the contribution of the trailing suction hopper dredgers during their various activities: dredging, transport, and discharge of sediment. Measured source levels of the dredgers, estimated source levels of other shipping, and time-dependent position data from a vessel-tracking system were used as input for a propagation model to generate dynamic sound maps. Various scenarios were studied to assess the risk of possible effects of the sound from dredging activities on marine fauna, specifically on porpoises, seals, and fish.

Marine waters have been poorly investigated for the occurrence of pharmaceutical contamination. Recent data confirm that pharmaceuticals occur widely in marine and coastal environments; therefore, assessment of potential risk to marine species needs further efforts. The present study represents the first extensive review of pharmaceutical contamination in marine environments addressing the effects on the marine biota analyzed at the molecular, cellular, and individual levels. Because pharmaceuticals differ from conventional pollutants, being designed to interact with specific physiological pathways at low doses, the most recent evidence on modes of action and physiological alterations on marine animal species are discussed. Data on spatial distributions of pharmaceuticals in waters and sediments, as well as bioaccumulation rates, are also presented. The present review also seeks to expand knowledge of how the quality of coastal and marine environments could be efficiently monitored to anticipate possible health and environmental risks.