Literature Library

Currently indexing 8050 titles

Assessing Northwest Pacific Fishery Stocks Using Two New Methods: The Monte Carlo Catch-MSY (CMSY) and the Bayesian Schaefer Model (BSM)

Ren Q-qiang, Liu M. Assessing Northwest Pacific Fishery Stocks Using Two New Methods: The Monte Carlo Catch-MSY (CMSY) and the Bayesian Schaefer Model (BSM). Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00430/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The CMSY and Bayesian Schaefer model (BSM) methods were applied to assess data-limited fishery stocks in the Japan Sea and surrounding areas of the Northwest Pacific. Ten stocks including 4 fish species and 5 cephalopod species were assessed; the CMSY method was used in 3 stocks with catch data only, and the BSM method in 7 stocks with both catch time series and catch per unit effort (CPUE) data available. The two methods estimated the maximum intrinsic rate of population increase (r) and carrying capacity of each stock, which allowed the computation of maximum sustainable yield (MSY), and exploited biomass relative to the biomass at maximum sustainable yield (B/BMSY). All 10 stocks were overfished, if to a different extent, and one, the spear squid (Heterololigo bleekeri) has collapsed. The reference points estimated here may be used as indicator for fishery management in this ecoregion.

Adaptive Capacity Level Shapes Social Vulnerability to Climate Change of Fishing Communities in the South Brazil Bight

Martins IMachado, Gasalla MA. Adaptive Capacity Level Shapes Social Vulnerability to Climate Change of Fishing Communities in the South Brazil Bight. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00481/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Understanding the social vulnerabilities and community strategies to adapt to environmental changes are crucial for the development of actions to enhance both community conservation and survival. With the aim to identify the drivers of vulnerability to climate change among different coastal communities a comprehensive multi-scale vulnerability framework was here adopted. Eight selected fishing communities representative of the South Brazil Bight (SBB) area were surveyed at the household level. A total of 151 fishers were interviewed. Quantitative indicators were calculated at the community-level, and their drivers identified, allowing for comparisons of the overall vulnerability score. Findings revealed that remoteness and the lack of climate change-related institutional support increase vulnerability among fishing communities in the region. On the other hand, community organization, leadership, research partnerships, community-based co-management, and livelihood diversification reduce vulnerability. Our analysis focused on social vulnerability to climate change in regional fishing communities and provides a better understanding of these effects in coastal zones, the factors explaining vulnerability and some perspectives on resilient and adaptable systems. Learning from comparisons at the ecosystem level may be applied to coastal regions elsewhere.

Climate Change Will Re-draw the Map for Marine Megafauna and the People Who Depend on Them

Grose SO, Pendleton L, Leathers A, Cornish A, Waitai S. Climate Change Will Re-draw the Map for Marine Megafauna and the People Who Depend on Them. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00547/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Climate change is expected to dramatically alter the distribution of many marine megafauna, impacting the people and economies that depend upon them. We build on the recent literature by developing a framework to describe the effects these changes will have on marine megafauna. With the goal to assist policymakers and grass roots organizers, we identify three illustrative pathways by which climate change drives these range shifts: (1) effects on habitat and shelter, (2) impacts on reproduction and disease, and (3) changing distribution of sources of food. We examine non-climate factors that may constrain or enable megafauna to adapt, creating winners and losers both for the species and the people dependent upon them. Finally, we comment on what management strategies exist at international and local scales that could help mitigate these impacts of climate change so that we, as a global community, can ensure that marine megafauna and people can best co-exist in a changing world.

Identification of a Soft Coral Garden Candidate Vulnerable Marine Ecosystem (VME) Using Video Imagery, Davis Strait, West Greenland

Long S, Sparrow-Scinocca B, Blicher ME, Arboe NHammeken, Fuhrmann M, Kemp KM, Nygaard R, Zinglersen K, Yesson C. Identification of a Soft Coral Garden Candidate Vulnerable Marine Ecosystem (VME) Using Video Imagery, Davis Strait, West Greenland. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00460/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The term vulnerable marine ecosystem (VME) was introduced to facilitate the spatial management of deep-seas, identifying those habitats vulnerable to anthropogenic disturbance, such as trawling. Consistent interpretation of the VME definition has been hampered by an underlying paucity of knowledge about the nature and distribution of deep-sea habitats. Photographic and video platforms yield data rich, quantifiable imagery to address these knowledge gaps. A low-cost towed benthic video sled has been used to investigate deep-sea habitats and trawling impacts in west Greenland. A review of imagery from multiple cruises highlighted an area where benthic megafauna contributes to notable structural complexity on the continental slope of the Toqqusaq Bank. Quantitative analysis of imagery from this area provides the first description of a soft coral garden habitat and other communities. The coral garden and observed densities are considered in relation to the VME guidelines (FAO, 2009) and wider literature. The study proposes a 486 km2 area spanning ∼60 km of continental slope as a VME. This has direct implications for the management of economically important deep-sea trawl fisheries, which are immediately adjacent. This furthers our knowledge and understanding of VMEs in North Atlantic, in a previously understudied region and demonstrates the utility of a low-cost video sled for identifying and describing VMEs.

Influence of Deep-Water Corals and Sponge Gardens on Infaunal Community Composition and Ecosystem Functioning in the Eastern Canadian Arctic

Pierrejean M, Grant C, Neves Bde Moura, Chaillou G, Edinger E, F. Blanchet G, Maps F, Nozais C, Archambault P. Influence of Deep-Water Corals and Sponge Gardens on Infaunal Community Composition and Ecosystem Functioning in the Eastern Canadian Arctic. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00495/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The relationships between infaunal diversity and ecosystem function of biogenic structures in the Eastern Canadian Arctic remain poorly documented. Our study investigated the influence of sponge gardens at the Frobisher Bay site (137 m) and bamboo corals at the Baffin Bay site (1007 m) on the infaunal community structure and benthic ecosystem functioning. The occurrence of both types of biogenic structure type enhanced particular taxa and/or feeding guilds. A large density of suspension filter feeders was observed in bamboo coral sediment, whereas bare sediment exhibited a large proportion of nematodes and deposit-detritus feeders. Sponge gardens’ sediment showed a high proportion of isopods, Paraonidae polychaetes and up/down conveyors whereas bare sediment exhibited a large density of filter feeders. Through incubation cores, we measured ex situ benthic nutrient and oxygen fluxes at the sediment-water interface in each habitat and site. Biogeochemical fluxes varied significantly between habitats in the Baffin Bay site with a significant impact of bamboo coral habitat on nutrient fluxes (nitrate, ammonium, and silicate). Surprisingly, the sediment hosting bamboo corals acted as a source of nitrate and ammonium reaching values similar or higher to the Frobisher site despite the difference in water depth, and thus food supply between the two sites. These significant releases could derive from (i) a high organic matter deposition in bamboo coral habitat, allowed by their erected structure, (ii) a high efficiency of bioturbators (surficial modifiers and burrowers) mixing the surface layer of the sediment, and (iii) the difference in sediment type. Our study highlighted that, compared to its adjacent habitat, the presence of bamboo corals appeared to enhance the infaunal density and nutrient release of its sediment. In contrast, the impact of sponge gardens was not as clear as for bamboo coral habitat, likely due to the relatively significant presence of megabiota in the sponge garden adjacent habitat. Thus, our results based on a relatively small sample size, indicate that the bamboo coral habitat seems to increase the efficiency of deep-benthic ecosystem functioning, while that of sponge garden on the shallow ecosystem functioning remains uncertain.

Ecosystem Functioning Under the Influence of Bottom-Trawling Disturbance: An Experimental Approach and Field Observations From a Continental Slope Area in the West Iberian Margin

Ramalho SP, Lins L, Soetaert K, Lampadariou N, Cunha MR, Vanreusel A, Pape E. Ecosystem Functioning Under the Influence of Bottom-Trawling Disturbance: An Experimental Approach and Field Observations From a Continental Slope Area in the West Iberian Margin. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00457/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Understanding the effects of bottom-trawling induced changes in benthic community structure, diversity and ecosystem functioning across different benthic-size components is imperative to determine the future sustainability of bottom-trawling fisheries in deep-sea regions. In this study, we combined field sampling observations with a pulse-chase experiment on sediments obtained from two stations of interest along the West Iberian Margin (WIM) distinguished by different trawling pressures. We compared these two stations in terms of meio- and macrofauna (infauna) standing stocks, biodiversity and several ecosystem function proxies. These proxies included: (i) 13C uptake by bacterial communities, (ii) infauna respiration rates, (iii) penetration of 13C in the sediment, and (iv) sediment pore-water nutrient concentrations. The pulse-chase experimental results were complemented with a larger biological dataset partially compiled from previous studies in the area, to investigate structural and functional diversity ecosystem functioning (respiration) patterns across the WIM. Our observations indicated that different regimes of trawling pressure influenced both macrofaunal respiration rates with disturbed sediments predominantly composed of deposit-/detritus-feeding smaller-sized macrofauna species. Moreover, sediment biogeochemical functioning (ammonium profiles) and 13C bacterial uptake showed differences among the two disturbance regimes. On the contrary, the biomass of small-sized biota, including bacteria and meiofauna, did not show marked differences between stations. The general depletion in macrofauna species richness across impacted areas of the study region was also correlated with a reduction in total biomass and respiration, suggesting that the long history of trawling disturbance at the WIM may affect regulatory ecosystem functions. These preliminary findings alert for the impacts of trawling on crucial functions of benthic ecosystems that may be imperceptible to the current tools used in monitoring programs.

The Biophysical Controls of Macroalgal Growth on Subtropical Reefs

Cordeiro CAugusto Ma, Harborne AR, Ferreira CEduardo Le. The Biophysical Controls of Macroalgal Growth on Subtropical Reefs. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00488/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1376892_45_Marine_20200714_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The importance of macro-grazers in controlling macroalgal cover has long been recognized on tropical and temperate reefs, with fishes of primary importance on the former and sea urchins on the latter. However, the functional role of herbivorous urchins and fishes on subtropical marginal reefs remains poorly explored. To evaluate the relative importance of fishes and urchins on marginal subtropical reefs, this study used exclusion devices (excluding all grazers, fishes, or urchins) at two depths (1–2, 5–6 m) on Brazilian rocky reefs. Depth influenced responses within cages, with shallow sites changing from patchy barrens (dominated by crustose coralline algae) to epilithic algae-dominated within exclusion treatments, and sea urchins being the primary driver of benthic dynamics. In deeper water, the growth and senescence cycle of Sargassum species drove benthic dynamics and was associated with the season of higher intensity of upwelling events. No clear influence of herbivorous fishes was detected on benthic cover at either depth, despite biomasses similar to comparable tropical reefs where they do control macroalgal populations. Thus, abiotic factors seem to be a strong driver of benthic dynamics in the studied region, and top-down processes act only at shallow depths. Consequently, despite Brazilian subtropical communities being dominated by tropical species, the ecological drivers of these reefs may be more similar to temperate systems.

Evaluating conservation biology texts for bias in biodiversity representation

Stahl K, Lepczyk CA, Christoffel RA. Evaluating conservation biology texts for bias in biodiversity representation Jenkins CN. PLOS ONE [Internet]. 2020 ;15(7):e0234877. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0234877
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

A critical component of textbooks is fair representation of the material they cover. Within conservation biology, fair coverage is particularly important given Earth’s breadth of species and diversity of ecosystems. However, research on species tends to be biased towards certain taxonomic groups and geographic areas and their associated ecosystems, so it is possible that textbooks may exhibit similar biases. Considering the possibility of bias, our goal was to evaluate contemporary conservation biology textbooks to determine if they are representative of Earth’s biodiversity. We found that textbooks did not accurately reflect Earth’s biodiversity. Species, ecosystems, and continents were unevenly represented, few examples mentioned genetic diversity, and examples of negative human influence on the environment outweighed positive examples. However, in terms of aquatic versus terrestrial representation, textbooks presented a representative sample. Our findings suggest that modern conservation biology textbooks are biased in their coverage, which could have important consequences for educating our next generation of scientists and practitioners.

Food safety during seaweed cultivation at offshore wind farms: An exploratory study in the North Sea

Banach JL, van den Burg SWK, van der Fels-Klerx HJ. Food safety during seaweed cultivation at offshore wind farms: An exploratory study in the North Sea. Marine Policy [Internet]. 2020 ;120:104082. Available from: https://www.sciencedirect.com/science/article/pii/S0308597X20301500
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Multi-use in ocean space, and seas, entails the co-location of different industries or technologies and their corresponding activities that take place at the same time in a specific location. This concept focuses on finding solutions to tackle global challenges in food security. However, the effects that seaweed cultivation at offshore wind farms may have on food and feed safety are less readily addressed. This study examined whether currently available food and feed safety standards for seaweed can be applied to multi-use activities at sea. The focus was on the combined use of seaweed cultivation at an offshore wind farm in the North Sea. Literature regarding hazards in seaweed was screened, and standards were evaluated. Expert elicitation on seaweed cultivation was retrieved via in-depth interviews and a workshop. Results showed that although some food safety hazards may be more apparent for seaweed cultivation such as toxic metals (e.g., arsenic, cadmium) and iodine, others may become relevant when considering multi-use (e.g., allergens, polycyclic aromatic hydrocarbons, toxic metabolites). Key factors for food safety include the location of seaweed cultivation, handling and processing of seaweed, and seaweed testing. Public standards, the Food Safety System Certification 22000 standard, and the Marine Stewardship Council/Aquaculture Stewardship Council standard are recommended for the food and marine sectors to consider when determining standards to implement. This case study provides an example of how to address seaweed food and feed safety in a multi-use scenario in the North Sea. We recommend additional case studies for other multi-use at sea scenarios.

A review on the potential effects of tsunami on built environment

A. Teresa REnid, Vasanth GDNJerry, Vidya C. A review on the potential effects of tsunami on built environment. Materials Today: Proceedings [Internet]. 2020 . Available from: https://www.sciencedirect.com/science/article/pii/S2214785320344667
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Over the past two decades, natural calamities like tsunamis and earthquakes occur more frequently, posing a serious threat to the human race. About 80% of these calamities have the “Ring of Fire” in the Pacific Ocean as its epicenter, causing extreme destructions due to the huge amount of energy and moving water bodies striking the adjoining land masses. Tsunamis cause heavy damage to human lives killing almost 430,000 lives since 1850, as it is almost impossible to flee from the mammoth waves. Huge waves collapse concrete buildings causing electrocution, explosion of gas plants, breakage of tanks and industries due to the floating debris that comes along with the killer waves. Following a tsunami, loss of infrastructures and economies is inevitable. This paper highlights the types of tsunamis and their potential effects on built structures and explains the association between tsunami related injuries and household level risk factors, including damages to built environment. Earlier studies have revealed that women, children and elderly citizens are at greater risk, and proximity to sea shores increase their risk of being affected. This finding, together with the risk of living in permanent structures in tsunami threatened areas should be an eye opener for the policy makers.

Fishery biomass trends of exploited fish populations in marine ecoregions, climatic zones and ocean basins

Palomares MLD, Froese R, Derrick B, Meeuwig JJ, Nöel S-L, Tsui G, Woroniak J, Zeller D, Pauly D. Fishery biomass trends of exploited fish populations in marine ecoregions, climatic zones and ocean basins. Estuarine, Coastal and Shelf Science [Internet]. 2020 :106896. Available from: https://www.sciencedirect.com/science/article/pii/S0272771419307644
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

This contribution presents time series of the ‘fishery biomass’ of fish populations, defined as the weight (whole-body, wet weight) of the in-water part of a fishable population, i.e., that part of a population (also called ‘stock’) that is exposed to a certain fishing gear. Detailed data of this type are only available for a limited number of species that are targets of the fisheries in the waters of economically developed regions, such as Europe, the USA, Canada or Australia. However, similar fishery biomass assessments are generally lacking for developing countries, even for many of their most heavily fished species. Here, an estimation of the long-term fishery biomass trends of 1320 fish and invertebrate populations for 483 species exploited by fisheries in the 232 coastal Marine Ecoregions (MEs) around the world was undertaken. Fishery biomass trends were derived using the Bayesian CMSY stock assessment method applied to the global fisheries catch database for 1950–2014 as reconstructed by the Sea Around Us for every maritime fishing country in the world. Overall, the results suggest a consistent decline in the fishery biomass of exploited populations, in virtually all climatic zones and ocean basins in the world. The only zone with currently higher fishery biomass than in 1950 is the northern Pacific polar-boreal zone, likely due to environmental changes that occurred in the region positively affecting fish populations, combined with prudent management of the fisheries. For populations in MEs that are known to have highly questionable catch statistics, the results suggested smaller declines in fishery biomass than likely occurred in reality, implying that these results do not exaggerate declining trends in fishery biomass. This study used informative Bayesian priors to improve the trend analyses in areas where systematic stock assessments were conducted. The use of these independent assessments reduced the uncertainty associated with the findings of this study.

Co-Management as a Successful Strategy for Marine Conservation

Voorberg W, Van der Veer R. Co-Management as a Successful Strategy for Marine Conservation. Journal of Marine Science and Engineering [Internet]. 2020 ;8(7):491. Available from: https://www.mdpi.com/2077-1312/8/7/491
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Marine Protected Areas (MPAs) are a primary tool for conserving marine biodiversity. The literature presents a scattered picture regarding the extent to which co-management can be considered valuable. In this study we examine, what conditions are for co-management to make a contribution to conserving marine ecosystems (e.g., stopping coral bleaching and safeguarding fish populations). By combining data on MPA management practices with a novel source of global biodata collected by citizens (ReefCheck), we demonstrate that if co-management is part of a formal governmental strategy, coral reefs show up to 86% fewer bleached colonies and up to 12.2 times larger fish populations than co-managed MPAs lacking formalized governmental support.

Can Water Constituents Be Used as Proxy to Map Microplastic Dispersal Within Transitional and Coastal Waters?

Piehl S, Atwood EC, Bochow M, Imhof HK, Franke J, Siegert F, Laforsch C. Can Water Constituents Be Used as Proxy to Map Microplastic Dispersal Within Transitional and Coastal Waters?. Frontiers in Environmental Science [Internet]. 2020 ;8. Available from: https://www.frontiersin.org/articles/10.3389/fenvs.2020.00092/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1371295_25_Enviro_20200707_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Due to high spatiotemporal variability of aquatic systems, relationships between microplastic sources and sinks are highly complex and transportation pathways yet to be understood. Field data acquisitions are a necessary component for monitoring of microplastic contamination but alone cannot capture such complex relationships. Remote sensing is a key technology for environmental monitoring through which extrapolation of spatially limited field data to larger areas can be obtained. In this field study we tested whether microplastic distribution follows the same transport pattern as water constituents depictable from satellite images, namely chlorophyll-a, suspended particulate matter, and colored dissolved organic matter, and discuss their applicability as proxies. As rivers are a major source for marine microplastic contamination, we sampled three example river systems: the lower courses and river mouths of the Trave and Elbe estuary in Germany and the Po delta in Italy. For a full quantitative analysis of microplastics (>300 μm), ATR- and FPA-based μFT-IR spectroscopy and NIR imaging spectroscopy were utilized. Comparing water constituents with in-situ data using regression analysis, neither a relationship for the Elbe estuary nor for the Po delta was found. Only for the Trave river, a positive relationship between microplastics and water constituents was present. Differences in hydrodynamic conditions and spatiotemporal dynamics of water constituents and microplastic emissions among the river systems are possible explanations for the contrary results. Based on our results no conclusions on other river systems and likewise different seasons can be drawn. For remote sensing algorithms of water constituents to be used as microplastic proxy an adaption for each system as well as for different seasons would thus be necessary. The lower detection limit of 300 μm for microplastics could also have influenced relationships as microplastic abundance exponentially increases with decreasing size class. Further studies with improved sampling methods are necessary to assess our proposed method.

Diatom aggregation when exposed to crude oil and chemical dispersant: Potential impacts of ocean acidification

Genzer JL, Kamalanathan M, Bretherton L, Hillhouse J, Xu C, Santschi PH, Quigg A. Diatom aggregation when exposed to crude oil and chemical dispersant: Potential impacts of ocean acidification Matsakas L. PLOS ONE [Internet]. 2020 ;15(7):e0235473. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235473
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Diatoms play a key role in the marine carbon cycle with their high primary productivity and release of exudates such as extracellular polymeric substances (EPS) and transparent exopolymeric particles (TEP). These exudates contribute to aggregates (marine snow) that rapidly transport organic material to the seafloor, potentially capturing contaminants like petroleum components. Ocean acidification (OA) impacts marine organisms, especially those that utilize inorganic carbon for photosynthesis and EPS production. Here we investigated the response of the diatom Thalassiosira pseudonana grown to present day and future ocean conditions in the presence of a water accommodated fraction (WAF and OAWAF) of oil and a diluted chemically enhanced WAF (DCEWAF and OADCEWAF). Tpseudonana responded to WAF/DCEWAF but not OA and no multiplicative effect of the two factors (i.e., OA and oil/dispersant) was observed. Tpseudonana released more colloidal EPS (< 0.7 μm to > 3 kDa) in the presence of WAF/DCEWAF/OAWAF/OADCEWAF than in the corresponding Controls. Colloidal EPS and particulate EPS in the oil/dispersant treatments have higher protein-to-carbohydrate ratios than those in the control treatments, and thus are likely stickier and have a greater potential to form aggregates of marine oil snow. More TEP was produced in response to WAF than in Controls; OA did not influence its production. Polyaromatic hydrocarbon (PAH) concentrations and distributions were significantly impacted by the presence of dispersants but not OA. PAHs especially Phenanthrenes, Anthracenes, Chrysenes, Fluorenes, Fluoranthenes, Pyrenes, Dibenzothiophenes and 1-Methylphenanthrene show major variations in the aggregate and surrounding seawater fraction of oil and oil plus dispersant treatments. Studies like this add to the current knowledge of the combined effects of aggregation, marine snow formation, and the potential impacts of oil spills under ocean acidification scenarios.

Modeling predator and prey hotspots: Management implications of baleen whale co-occurrence with krill in Central California

R. Rockwood C, Elliott ML, Saenz B, Nur N, Jahncke J. Modeling predator and prey hotspots: Management implications of baleen whale co-occurrence with krill in Central California Bersier L-F. PLOS ONE [Internet]. 2020 ;15(7):e0235603. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235603
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

As global ocean-bound commerce increases, managing human activities has become important in reducing conflict with threatened wildlife. This study investigates environmental factors determining abundance and distribution of blue whales (Balaenoptera musculus), humpback whales (Megaptera novaeangliae) and their prey (Euphausia pacifica and Thysanoessa spinifera) in central California. We provide insights into environmental drivers of the ecology and distribution of these species, model whale distributions and determine coincident hotspots of whales and their prey that will help decrease human threats to whales and protect critical feeding habitat. We developed separate predictive models of whale abundances (using negative binomial regression on count data) and krill abundance (using a two-part hurdlemodel combining logistic and negative binomial regressions) over a 14 year period (2004–2017). Variables included in situ surface and midwater oceanographic measures (temperature, salinity, and fluorescence), basin-scale climate indices, and bathymetric- and distance-related data. Predictions were applied to 1 km2 cells spanning the study area for May, June, July, and September during each of the 14 years of surveys to identify persistent distribution patterns. Both whales and krill were found to consistently use the northeast region of Cordell Bank, the Farallon Escarpment, and the shelf-break waters. The main identified blue whale hotspots were also krill hotspots, while co-occurrence was more limited and varied seasonally for humpback whales and krill. These results are valuable in identifying patterns in important areas of ecological interaction to assist management of whales. Areas north of Cordell Bank are of particular management concern since they overlap with the end of the San Francisco Bay northern shipping lane. Our findings can help decrease threats to whales, particularly in important foraging areas, by supporting implementation of vessel management and informing potential conflicts with other human uses.

The use of Unmanned Aerial Vehicles (UAVs) to sample the blow microbiome of small cetaceans

Centelleghe C, Carraro L, Gonzalvo J, Rosso M, Esposti E, Gili C, Bonato M, Pedrotti D, Cardazzo B, Povinelli M, et al. The use of Unmanned Aerial Vehicles (UAVs) to sample the blow microbiome of small cetaceans Caballero S. PLOS ONE [Internet]. 2020 ;15(7):e0235537. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235537
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Recent studies describe the use of UAVs in collecting blow samples from large whales to analyze the microbial and viral community in exhaled air. Unfortunately, attempts to collect blow from small cetaceans have not been successful due to their swimming and diving behavior. In order to overcome these limitations, in this study we investigated the application of a specific sampling tool attached to a UAV to analyze the blow from small cetaceans and their respiratory microbiome. Preliminary trials to set up the sampling tool were conducted on a group of 6 bottlenose dolphins (Tursiops truncatus) under human care, housed at Acquario di Genova, with approximately 1 meter distance between the blowing animal and the tool to obtain suitable samples. The same sampling kit, suspended via a 2 meter rope assembled on a waterproof UAV, flying 3 meters above the animals, was used to sample the blows of 5 wild bottlenose dolphins in the Gulf of Ambracia (Greece) and a sperm whale (Physeter macrocephalus) in the southern Tyrrhenian Sea (Italy), to investigate whether this experimental assembly also works for large whale sampling. In order to distinguish between blow-associated microbes and seawater microbes, we pooled 5 seawater samples from the same area where blow samples’ collection were carried out. The the respiratory microbiota was assessed by using the V3-V4 region of the 16S rRNA gene via Illumina Amplicon Sequencing. The pooled water samples contained more bacterial taxa than the blow samples of both wild animals and the sequenced dolphin maintained under human care. The composition of the bacterial community differed between the water samples and between the blow samples of wild cetaceans and that under human care, but these differences may have been mediated by different microbial communities between seawater and aquarium water. The sperm whale’s respiratory microbiome was more similar to the results obtained from wild bottlenose dolphins. Although the number of samples used in this study was limited and sampling and analyses were impaired by several limitations, the results are rather encouraging, as shown by the evident microbial differences between seawater and blow samples, confirmed also by the meta-analysis carried out comparing our results with those obtained in previous studies. Collecting exhaled air from small cetaceans using drones is a challenging process, both logistically and technically. The success in obtaining samples from small cetacean blow in this study in comparison to previous studies is likely due to the distance the sampling kit is suspended from the drone, which reduced the likelihood that the turbulence of the drone propeller interfered with successfully sampling blow, suggested as a factor leading to poor success in previous studies.

A mini ROV-based method for recovering marine instruments at depth

Tarnecki JH, Patterson WF. A mini ROV-based method for recovering marine instruments at depth Hewitt J. PLOS ONE [Internet]. 2020 ;15(7):e0235321. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235321
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Instruments are often deployed at depth for weeks to years for a variety of marine applications. In many cases, divers can be deployed to retrieve instruments, but divers are constrained by depth limitations and safety concerns. Acoustic release technology can also be employed but can add considerable expense and acoustic releases will at times fail. Here, we report a simple method that utilizes a commercially available mooring hook integrated with a mini remotely operated vehicle to attach lines to instruments deployed on the sea floor, which can then be winched to the surface. The mooring hook apparatus was tested in a pool setting and then used to retrieve acoustic telemetry receiver bases (50 kg) or fish traps (30–50 kg) from the northern Gulf of Mexico continental shelf at depths between 28 and 80 m. During 2013–2019, 539 retrievals (100% success rate) were made of receiver bases (n = 239) and traps (n = 300) on 30 sea days using this approach. This method could easily be applied to other types of instruments, or recovery and salvage of objects that are too deep for standard diving operations.

Synthetic Microfiber and Microbead Exposure and Retention Time in Model Aquatic Species Under Different Exposure Scenarios

Bour A, Hossain S, Taylor M, Sumner M, Almroth BCarney. Synthetic Microfiber and Microbead Exposure and Retention Time in Model Aquatic Species Under Different Exposure Scenarios. Frontiers in Environmental Science [Internet]. 2020 ;8. Available from: https://www.frontiersin.org/articles/10.3389/fenvs.2020.00083/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1371295_25_Enviro_20200707_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Synthetic microfibers have been reported in most aquatic environments and represent a large proportion of environmental microplastics. However, they remain largely under-represented in microplastic ecotoxicity studies. The present study aims to investigate particle interaction with, and retention time in, aquatic organisms comparing microfibers, and microbeads. We used brine shrimp (Artemia sp.) and fish (Gasterosteus aculeatus) as invertebrate and vertebrate models, respectively. Organisms were exposed to a mixture of microbeads (polyethylene, 27–32 μm) and microfibers (dope dyed polyester; 500 μm-long) for 2 h, at high concentrations (100,000 part./L) in order to maximize organism-particles interaction. Artemia were exposed in the presence or absence of food. Fish were exposed either via the trophic route or directly via water, and water exposures were performed either in freshwater or seawater. In the absence of food, Artemia ingested high numbers of microbeads, retained in their digestive tract for up to 96 h. Microfiber ingestion was very limited, and its egestion was fast. In the presence of food, no microfiber was ingested, microbead ingestion was limited, and egestion was fast (48 h). Limited particle ingestion was observed in fish exposed via water, and particle retention time in gut did not exceed 48 h, both for direct and trophic exposure. However, water exposures resulted in a higher number of particles present in gills, and average retention time was higher in gills, compared to gut. This suggests that gills are organs susceptible to microplastic exposure and should be taken into account in fish exposure and effect studies. Our results show that particle ingestion and retention by organisms differ between microbeads and microfibers, suggesting particle selection based on size, shape, and/or color and species-specific selective feeding. We also showed that the presence of food results in limited particle ingestion and retention in Artemia and that microbeads are more likely to be transferred to organisms from upper trophic levels than microfibers. Finally, fish exposure to particles was not significantly different between freshwater and seawater conditions.

Community structure of actively growing bacteria in a coastal fish-farming area

Taniguchi A, Eguchi M. Community structure of actively growing bacteria in a coastal fish-farming area Hewitt J. PLOS ONE [Internet]. 2020 ;15(6):e0235336. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235336
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

In fish-farming areas, copious amounts of organic matter are released into the surrounding environment. Although it is well-known that bacterial community structures and activities are tightly coupled with organic conditions in the environment, actively growing bacteria (AGB) species that are responsible are still largely unknown. Here, we determined seasonal variations in the community structures of free-living and particle-attached AGB in surface and bottom seawater, and also in the easily resuspendable sediment boundary layer. Accordingly, we used bromodeoxyuridine (BrdU) magnetic bead immunocapture and PCR-denaturing gradient gel electrophoresis (BUMP-DGGE) analysis. Whereas overall bacterial communities in the resuspendable sediment were quite different from those of the free-living and particle-attached bacteria, the AGB community structures were similar among them. This result suggests that sediment resuspension in aquaculture environments functions as an organic source for bacteria in the water column, and that bacterial species contributing to the environmental capacity and carbon cycle are limited. We identified 25 AGB phylotypes, belonging to Alphaproteobacteria (Roseobacter clade, nine phylotypes), Gammaproteobacteria (five phylotypes), Deltaproteobacteria (one phylotype), Bacteroidetes (seven phylotypes), and Actinobacteria (three phylotypes). Among them, some AGB phylotypes appeared throughout the year with high frequency and were also identified in other coastal environments. This result suggests that these species are responsible for the environmental capacity and carbon cycle, and are key species in this fish-farming area, as well as other coastal environments.

When are researchers willing to share their data? – Impacts of values and uncertainty on open data in academia

Stieglitz S, Wilms K, Mirbabaie M, Hofeditz L, Brenger B, López A, Rehwald S. When are researchers willing to share their data? – Impacts of values and uncertainty on open data in academia Paniagua J. PLOS ONE [Internet]. 2020 ;15(7):e0234172. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0234172
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Background

E-science technologies have significantly increased the availability of data. Research grant providers such as the European Union increasingly require open access publishing of research results and data. However, despite its significance to research, the adoption rate of open data technology remains low across all disciplines, especially in Europe where research has primarily focused on technical solutions (such as Zenodo or the Open Science Framework) or considered only parts of the issue.

Methods and findings

In this study, we emphasized the non-technical factors perceived value and uncertainty factors in the context of academia, which impact researchers’ acceptance of open data–the idea that researchers should not only publish their findings in the form of articles or reports, but also share the corresponding raw data sets. We present the results of a broad quantitative analysis including N = 995 researchers from 13 large to medium-sized universities in Germany. In order to test 11 hypotheses regarding researchers’ intentions to share their data, as well as detect any hierarchical or disciplinary differences, we employed a structured equation model (SEM) following the partial least squares (PLS) modeling approach.

Conclusions

Grounded in the value-based theory, this article proclaims that most individuals in academia embrace open data when the perceived advantages outweigh the disadvantages. Furthermore, uncertainty factors impact the perceived value (consisting of the perceived advantages and disadvantages) of sharing research data. We found that researchers’ assumptions about effort required during the data preparation process were diminished by awareness of e-science technologies (such as Zenodo or the Open Science Framework), which also increased their tendency to perceive personal benefits via data exchange. Uncertainty factors seem to influence the intention to share data. Effects differ between disciplines and hierarchical levels.

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