Invertebrate Samples Research Articles

Impact of Nesting Socotra Cormorants on Terrestrial Invertebrate Communities

Simple SummarySeabirds that breed on remote islands often form dense nesting colonies. Nesting activities during the course of a breeding season could result in the deposition of large quantities of feces that could influence soil biodiversity. We determined the impact nesting activities of Socotra Cormorants on soil invertebrates using artificial substrate samplers. Nesting activities had variable effects on soil invertebrates. Isopods and spiders declined in due to nesting activities. Beetles and ants seemed to be unaffected by nesting activities. Ticks increased significantly but in non-nesting areas. Our study shows that seabird breeding activities determine long-term community structure of remote islands by affecting different invertebrate taxa in different ways.Seabirds and some inland waterbirds nest in densely aggregated colonies. Nesting activities for a duration of months could lead to large quantities of guano deposition that affects the soil chemistry, flora and fauna. We assessed the effects of nesting Socotra Cormorants on soil invertebrates on Siniya Island, United Arab Emirates. Artificial substrate traps were set in nesting and non-nesting areas to sample invertebrates both before and after nesting had occurred. Diversity of soil invertebrate taxa decreased significantly in nesting areas compared to non-nesting areas after the commencement of nesting. This indicated that nesting activities had a negative effect on diversity. Among selected taxa, isopods and spiders decreased significantly in response to nesting activities. In contrast, ants were likely affected by habitat while beetles did not change significantly in response to nesting activities, suggesting that their numbers probably fluctuated in relation to seasonality. Ticks increased significantly but only in non-nesting areas. Thus, the impact of nesting varied between taxa depending on life history and seasonality. Our observations reflect the dynamic nature of invertebrate abundance that is affected by seasonality and the hyper-abundance of nesting seabirds.

Hepatitis Delta Virus (HDV) and Delta-Like Agents: Insights Into Their Origin.

Hepatitis delta virus (HDV) is a human pathogen, and the only known species in the genus Deltavirus. HDV is a satellite virus and depends on the hepatitis B virus (HBV) for packaging, release, and transmission. Extracellular HDV virions contain the genomic HDV RNA, a single-stranded negative-sense and covalently closed circular RNA molecule, which is associated with the HDV-encoded delta antigen forming a ribonucleoprotein complex, and enveloped by the HBV surface antigens. Replication occurs in the nucleus and is mediated by host enzymes and assisted by cis-acting ribozymes allowing the formation of monomer length molecules which are ligated by host ligases to form unbranched rod-like circles. Recently, meta-transcriptomic studies investigating various vertebrate and invertebrate samples identified RNA species with similarities to HDV RNA. The delta-like agents may be representatives of novel subviral agents or satellite viruses which share with HDV, the self-complementarity of the circular RNA genome, the ability to encode a protein, and the presence of ribozyme sequences. The widespread distribution of delta-like agents across different taxa with considerable phylogenetic distances may be instrumental in comprehending their evolutionary history by elucidating the transition from transcriptome to cellular circular RNAs to infectious subviral agents.

Influences of environmental parameters and phytoplankton productivity on benthic invertebrates in a tropical oligotrophic lake, northern Malaysia

Studies that associate environmental parameters with aquatic organisms in man-made lakes remain limited by accessibility and interest particularly in many Asian countries. With missed opportunities to monitor environmental transitions at Lake Kenyir, our knowledge of lake transition is restricted to the non-mixing shallow waters only. Triplicate monthly benthic invertebrate samples were collected concurrently with various environmental parameters at three locations (zones A-C) of Kenyir Lake, Malaysia. Our results affirmed that the northeast part of Lake Kenyir is oligotrophic. Abundance of phytoplankton, total suspended solids, phosphate, nitrite and nitrate drive the abundance of various groups of benthic invertebrates. All of these extrinsic variables (except phosphate) negatively influenced the density of Trichoptera and positively influenced (P<0.05) the densities of Polychaeta, Oligochaeta, Bivalvia, Gastropod, Isopoda and Copepod in all zones. Phosphate negatively influenced the density of Trichoptera and positively influenced (P<0.05) the densities of Oligochaeta, Bivalvia and Copepod. Its influences on the Polychaeta, Gastropod and Isopoda densities were zone-specific. Overall, seasons equally influenced the relationships between extrinsic and response variables in all zones. The results of this study are useful to evaluate the lake's environmental quality, in conservation and in similar projects involving environmental handling, monitoring and recovery.

Are Vertebrates Still Needed in Routine Whole Effluent Toxicity Testing for Oil and Gas Discharges?

Routine whole effluent toxicity (WET) testing is commonly used to monitor effluent discharges for regulatory compliance in North America. However, the use of fish in WET testing raises ethical concerns and therefore an important question to be explored is whether invertebrates can be used to reduce and/or replace the need for vertebrate testing. The present study evaluated WET data collected for regulatory compliance between 2003 and 2019 (n = 2581 endpoints) from 20 different stationary onshore and offshore oil and gas facilities located across Canada and the United States. Our objective was to assess the relative sensitivity between vertebrates (i.e., fish) and invertebrates in paired samples and to evaluate trends in WET compliance. Despite the variability in testing endpoints, invertebrates displayed equal to or greater sensitivity to tested effluents than fish. For example, based on no-observed-effect concentrations for survival and growth, Americamysis bahia was found to be protective of Menidia beryllina in 90% of endpoint comparisons (n = 336). The results also indicated that regulatory compliance was high (94-100%), with most WET tests passing the established criteria by large margins (79-251%). The results of this comprehensive analysis of historical WET data can be used to improve future permit testing requirements and help answer the question of whether fish tests are needed for routine WET testing. Environ Toxicol Chem 2021;40:1255-1265. © 2020 SETAC.

Evaluating candidate wetlands for the assisted colonization of the western swamp turtle Pseudemydura umbrina in a changing climate: Macro‐invertebrate food resources and turtle diet

Abstract The natural habitat of the western swamp turtle (Pseudemydura umbrina Siebenrock, 1901) – the ephemeral, winter wet swamps north of Perth, Australia – is in danger owing to climate change and habitat fragmentation. The decline in rainfall in this area over the last five decades is predicted to continue, shortening the annual activity period for the turtles and potentially shifting their optimal climate zone to the south. Assisted colonization to wetlands in the cooler far south west of the state is one management response. As a contribution to such a measure, the diversity and abundance of food resources and consumption by turtles were evaluated at two potential and one existing colonization site. Thirty‐five captive‐bred juvenile P. umbrina were temporarily released into three sites: Moore River Nature Reserve north of Perth (into which the species had already been successfully translocated) and Meerup and East Augusta in the cooler far south of Western Australia. Food resources were assessed using sweep nets to sample invertebrates on two occasions at each wetland. Separate samples were collected for biomass determination and for assessing invertebrate diversity. Feeding by turtles was assessed by stomach flushing. Neither biomass nor biodiversity differed significantly between the southern sites and the reference site north of Perth. Stomach contents varied greatly, from 0 to 62 animals per turtle. The main prey items were beetles, ostracods, isopods and tadpoles. Each candidate wetland provided adequate food resources, indicating that assisted colonization to the cooler south coast of Western Australia has the potential to become a reasonable conservation tool to ensure the long‐term survival of P. umbrina.

Biomagnification and trophic transfer of total mercury and methylmercury in a sub-tropical montane forest food web, southwest China

Little is known about the bioaccumulation and trophic transfer of total mercury (THg) and methylmercury (MeHg) via food webs in terrestrial ecosystems, especially in subtropical forest ecosystems. In the present study, THg and MeHg were determined as well as the carbon (δ13C) and nitrogen (δ15N) isotope composition in samples of soils, plants, invertebrates, and songbird feathers to construct food webs in a remote subtropical montane forest in Mt. Ailao, southwest China and assess the bioaccumulation, biomagnification, and trophic transfer of Hg. Results showed that the trophic levels (TLs) of all consumers ranged from 0.8 to 3.3 and followed the order of songbirds > spiders > omnivorous insects > herbivorous insects > plants, and THg and MeHg exhibited a clear biomagnification up the food chain from plants-herbivorous/omnivorous insects-spiders-songbirds. The lowest MeHg concentration was observed in pine needles ranged from 0.104 to 0.949 ng g−1 with only a 1.6% ratio of MeHg to THg (MeHg%), while the highest MeHg concentrations ranged from 425 to 5272 ng g−1 in songbirds with MeHg% values of up to 96%. High values of trophic magnification slope (TMS) for THg (0.22) and MeHg (0.38) were observed in plant-invertebrate-songbird food chain, verifying the significant bioaccumulation of Hg, particularly MeHg, in the remote subtropical forest ecosystem. This study confirmed the production and efficient biomagnification of MeHg in remote subtropical montane forest and the significant bioaccumulation of MeHg in terrestrial top predators.

Comparative Investigation of Aquatic Invertebrates in Springs in Münsterland Area (Western Germany)

The main aim of this study was to investigate the abundance of invertebrates in groundwater in relation to groundwater conditions (groundwater table, discharge, rainfall, and physio-chemical parameters), and to examine the suitable time for invertebrate sampling in springs. Thus, eight springs in two separate study areas, “Baumberge” and “Schöppinger Berg” (Münsterland area, North-Rhine Westphalia in Germany), were sampled five times (24 h for 2–5 consecutive sampling days) between November 2018 and October 2019. The results showed high spatial and temporal variance. In general, the existence of invertebrates and stygobites increased, whereas invertebrate types decreased with increasing hydraulic head and spring discharge. Therefore, investigating the abundance of invertebrates and invertebrate species is recommended to be done separately. Abundance of invertebrates was affected by different factors in both areas. Spearman correlation test (two-tailed) and factor analyses (n = 80, p ≤ 0.01) highlighted the importance of detritus as the main controlling factor for invertebrate existence and stygobite individuals in Baumberge, whereas dissolved oxygen is essential for their existence in Schöppinger Berg.

Specific indicator invertebrates of urbanized habitats in tributary streams of the Luján River basin (Buenos Aires, Argentina)

The increase of urbanized areas produces disturbances in rivers and streams, and its widespread effects reduce water quality and threaten aquatic biota. The aim of this study was to analyze changes in the invertebrate communities of the Luján River basin (Buenos Aires Province, Argentina) in an urbanization gradient and to determine the specific indicator taxa of urbanized habitats. Nine sampling sites were selected in the Luján River basin, distributed along a land use gradient. At each sampling site physicochemical variables of water were recorded, and invertebrate samples were collected during four seasons. A Principal Component Analysis separated three groups of sites with different urbanization conditions: low (&lt;15%), moderate (between 15% and 60%) and high urbanization (&gt;60%). These groups showed differences in the concentration of dissolved oxygen, suspended particulate organic matter, and nitrates. The communities changed with urbanization conditions, with a simplification of the community composition and a decrease in richness towards the lower basin (moderate and high urbanization). The IndVal method found three indicator taxa for the low urbanization sites (Heleobia sp. (Cochliopidae), Uncancylus sp. (Ancylidae) and Callibaetis sp. (Baetidae)) and three for the moderate urbanization habitats (Nematoda, Hyalella curvispina (Hyalellidae) and Chironominae). These taxa were useful to identify different disturbance conditions due to urbanization, which makes them potential bioindicators in the diagnosis and monitoring of water quality in the Luján River basin.

Multiple stressor effects on benthic macroinvertebrates in very large European rivers – A typology-based evaluation of faunal responses as a basis for future bioassessment

Two factors complicate the ecological status classification of very large rivers in Europe according to the EU Water Framework Directive: First, current assessment methods do not fully consider the specific ecology of very large rivers (such as lateral connectivity and the role of floodplains for ecological status). Second, most of Europe's very large rivers have been severely altered by human activities such as flood protection, damming and navigation. The aim of our study is to develop an assessment method for very large rivers by identifying suitable biological metrics as the basis for multi-metric bioassessment using benthic invertebrates. Based on the pan-European typology of very large rivers by Borgwardt et al. (2019), we established a river type-specific assessment approach using invertebrate samples from 25 European countries and 94 very large rivers. The frequency and intensity of eight pressures jointly acting on the sampling sites were described, and a selection of suitable invertebrate community metrics were correlated with the pressure intensities to establish pressure-response relationships. The very large river types differ in terms of relevant pressures and pressure combinations, with the invertebrate communities distinctly responding to these pressure patterns. Neozoa dominance correlated strongly with ‘navigation’, being a major pressure at very large rivers, which entails severe hydro-morphological alterations such as channelization, riparian vegetation alteration and impoundment. Under combined pressures, a critical community turnover became evident in terms of neozoa outnumbering EPT taxa and the ratio of hemilimnic invertebrates decreasing. We propose ten bioassessment metrics, including measures of biological diversity as well as newly generated indicators, for the development of a European type-specific assessment method for very large rivers.

Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

AbstractThe annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.

Feeding preferences in aquatic invertebrates associated to Egeria densa in a tropical high-mountain lake

Introduction: The benthic fauna of the littoral zone in lakes is important in transferring energy to other trophic levels, habitat coupling, and helping to keep habitat stability. The study of this type of interactions in lentic systems is priority, since functional aspects about biological communities are unknown. Objective: Describing the trophic relations of aquatic invertebrates of the littoral zone in a tropical high mountain lake by characterizing gut content and stable isotope analysis of δ13C and δ15N. Methods: Samples of benthic invertebrates were collected in the littoral zone of the Lago de Tota where Egeria densa was present using a handheld net method. Samples were processed in the laboratory, organisms were identified, counted and weighed. Gut contents and δ13C and δ15N stable isotopes analysis were performed as well. Results: Records of the trophic relations of aquatic invertebrates, which live in the littoral in high mountain lentic ecosystem in the Neotropics are shown. The analysis of gut contents distinguished seven food items, microphytes and MOPF were the most frequent, and through the stable isotopes analysis (δ15N) we identified four trophic levels, among resources (macrophytes and POM), and consumers (detritivores, herbivores, and predators). The two upper trophic levels concentrated greater diversity and biomass. Conclusion: Most of the organisms studied were linked to omnivorous habits, evidenced in a wide spectrum of food items in their diet. The δ15N values show an enrichment, which occurs due to the effects of the tendency towards eutrophication of the system or due to unknown values of protozoa and bacteria that plays a fundamental role in the diet of these organisms, besides the δ13C values reported in organisms consumes, allows us to suggest an affinity with native resources of the littoral zone.

Do changes in temperature affect EU Water Framework Directive compliant assessment results of central European streams?

BackgroundBenthic invertebrate communities are an integral and longstanding component of stream biomonitoring. However, multiple stressors driven by global change threaten benthic invertebrate communities. In particular, climate warming is expected to disrupt freshwater ecosystems. While an increasing number of studies have shown changes in benthic invertebrate community composition in response to climate warming, the effect on stream assessments has rarely been investigated. As several community composition metrics are also used in stream assessments, we predicted that climate warming would worsen stream assessment results. Therefore, we used a comprehensive data set of 2865 benthic invertebrate samples taken between 2000 and 2014 from small central European low mountain streams. We examined the effects of changes in temperature on common community and stream assessment metrics. We used 31 metrics covering composition, richness, tolerance and function of communities, of which many are used in various stream assessment schemes.ResultsAgainst our expectations, we identified a decreasing air temperature trend of − 0.18 °C over 15 years. This trend was accompanied by significant changes in community composition, for example, increases in species richness and decreases in the community temperature index (CTI). Further, we identified slight concomitant improvements of various globally used stream quality assessment metrics, such as a decreasing saprobic index and an increasing BMWP.ConclusionsWhile temperature increased by + 0.9 °C during the past 30 years (1985–2014), our 15-year study period (2000–2014) showed a decrease by − 0.18 °C. Therefore, we regard the concomitant improvement in several assessment metrics as a recovery from prior increasing temperatures. In turn, we assume that increases in water temperature will lead to opposite effects and therefore cause declining assessment results. Water managers should be aware of this linkage that in turn could provide a chance to mitigate the effects of global warming by, for example, planting trees along the rivers and the removal of artificial barriers to increase current velocity to minimize a warming effect.

Automatic image‐based identification and biomass estimation of invertebrates

Abstract Understanding how biological communities respond to environmental changes is a key challenge in ecology and ecosystem management. The apparent decline of insect populations necessitates more biomonitoring but the time‐consuming sorting and expert‐based identification of taxa pose strong limitations on how many insect samples can be processed. In turn, this affects the scale of efforts to map and monitor invertebrate diversity altogether. Given recent advances in computer vision, we propose to enhance the standard human expert‐based identification approach involving manual sorting and identification with an automatic image‐based technology. We describe a robot‐enabled image‐based identification machine, which can automate the process of invertebrate sample sorting, specimen identification and biomass estimation. We use the imaging device to generate a comprehensive image database of terrestrial arthropod species which is then used to test classification accuracy, that is, how well the species identity of a specimen can be predicted from images taken by the machine. We also test sensitivity of the classification accuracy to the camera settings (aperture and exposure time) to move forward with the best possible image quality. We use state‐of‐the‐art Resnet‐50 and InceptionV3 convolutional neural networks for the classification task. The results for the initial dataset are very promising as we achieved an average classification accuracy of 0.980. While classification accuracy is high for most species, it is lower for species represented by less than 50 specimens. We found significant positive relationships between mean area of specimens derived from images and their dry weight for three species of Diptera. The system is general and can easily be used for other groups of invertebrates as well. As such, our results pave the way for generating more data on spatial and temporal variation in invertebrate abundance, diversity and biomass.

The effects of squid-baiting pitfall traps for sampling wētā (Orthoptera) and other ground-dwelling forest invertebrates

ABSTRACT Pitfall traps are commonly used to sample surface-active invertebrates, although the efficiency of the technique varies among taxa. We investigated how baiting pitfall traps with squid influenced sampling of some ground-dwelling invertebrates in New Zealand forests. The study was conducted across a total of 21 sets of seven lethal pitfall traps established between November 2012 and November 2015 in Aorangi and Remutaka forests. Four non-baited and three squid-baited lethal pitfall traps were established per set and remained active for one night during November/December and three nights during February. Squid-baited pitfall traps caught four times as many ground wētā and three times more cave wētā per unit effort than unbaited traps. Most of the ground wētā were identified as Hemiandrus pallitarsis (Walker, 1869). Carabidae, Scarabaeidae, Staphylinidae, Opiliones, Hymenoptera and Araneae were also more abundant in squid-baited than in unbaited traps. There was little difference in the catches of peripheral pitfall traps versus central pitfall traps, suggesting that 5 m spacing is sufficient to generate independent samples. Exceptions were Araneae and Amphipoda which were both approximately 1.5 times more abundant in central compared to peripheral unbaited traps. The attraction of ground and cave wētā to squid provides some insight into their dietary range. The higher catches obtained with squid-baiting, suggests this may be a useful modification to increase sampling rates, which is valuable where sampling effort is logistically constrained such as on islands or other remote study sites.

Factors Shaping Breeding Phenology in Birds: An Assessment of Two Sympatric Acrocephalus Warblers with Different Life Histories

Timing of reproduction is a critical life-history trait and implies major fitness consequences. Differences in life history strategies can lead to different responses to the same environmental conditions even among closely related species. Investigating the factors affecting the timing of reproduction in closely related and sympatric species may help understanding the relationship between different life history traits and species-specific responses to ecological factors. We investigated the effects of season (photoperiod), local climatic variability and prey abundance on the breeding season of two sympatric insectivorous birds that differ in the timing of reproduction and moult and have different migration strategies: the Moustached Warbler Acrocephalus melanopogon and the Eurasian Reed-warbler Acrocephalus scirpaceus. During a five-year period, breeding phenology was determined by examining bird incubation patches during standardised captures and food availability was assessed by invertebrate sampling. Time, mean temperatures and the abundance of some prey taxa were inter-correlated and all contributed to influence the breeding phenology of both species according to partial least squares regression analysis. Besides some interspecific differences in the effect of environmental factors on the breeding phenology, we found strong similarities between the patterns observed in the two warblers. This suggests that, in spite of interspecific differences in life history, the ecological mechanisms shaping reproduction phenology are similar in the two warblers and the same environmental factors are involved in determining the timing of their reproduction.—Ceresa, F., Belda, E.J., Brambilla, M., Gómez, J., Mompó, C. & Monrós, J.S. (2020). Factors shaping breeding phenology in birds: an assessment of two sympatric Acrocephalus warblers with different life histories. Ardeola, 67: 371-385.

Trophic transfer of polybrominated diphenyl ethers in a recently modified freshwater food web from the St. Lawrence River, Canada

Introduction of invasive species can have a profound impact on food web structure and therefore on trophic transfer of contaminants. In the St. Lawrence River (Canada), 20 years after its first detection in the system, invasive round goby (Neogobius melanostomus) has become the main prey for several piscivorous species. To evaluate the accumulation, trophic transfer, and the ecological risk of polybrominated diphenyl ethers (PBDEs) in this recently modified freshwater food web, samples of sediment, invertebrates, fish and aquatic bird eggs and plasma were collected. Sampling sites were located upstream and at two locations downstream of the Montreal wastewater treatment plant outfall. The results suggest that the influence of the WWTP effluent on PBDEs concentrations varied among the various compartments of this recently modified freshwater food web. The results also suggest that although predatory fish have switched to consuming round goby as a prey item instead of native yellow perch, this new feeding behaviour is not expected to have important impacts on the level of transfer of PBDE within this food web. The biota-sediment accumulation factors (BSAFs) ranged from 0.6 to 436, whereas biomagnification factors (BMFs) varied between 0.2 and 475. Despite our conservative method of risk assessment, we calculated an important risk for piscivorous fish and gull eggs within this study area.

Influence of habitat heterogeneity and bed surface complexity on benthic invertebrate diversity in a gravel‐bed river

AbstractMaintaining or restoring physical habitat diversity is a central tenet of sustainable river management, yet a link between habitat and ecological diversity in fluvial systems has long remained equivocal. The lack of consistent evidence partly reflects the problems of characterizing habitat in ways that are ecologically meaningful. This paper assesses the influence of habitat heterogeneity and complexity on macroinvertebrate assemblages in a mountain gravel‐bed river. With the use of 0.1‐m resolution data obtained from an acoustic Doppler current profiler, heterogeneity and complexity in hydraulic conditions and bed topography were characterized using 13 metrics applied to 30 areas, each 1 m2, with an invertebrate sample collected from each area. Turnover of invertebrate taxa (i.e., β‐diversity) between sampled areas was rather limited, but observed differences in diversity were related significantly to several metrics of habitat heterogeneity. Invertebrate abundance was related to habitat diversity, patch size coefficient of variation, and patch size, whereas the Shannon diversity was related to the number of patches and patch size. None of the habitat complexity metrics accounted for a significant amount of observed variation in invertebrate communities between sampled areas. The paper demonstrates that high‐resolution data can help reveal relationships between habitat and benthic invertebrate diversity.

The effect of culture media on the number and bioactivity of marine invertebrates associated fungi

Abstract. Trianto A, Radjasa OK, Sibero MT, Sabdono A, Haryanti D, Zilullah WOM, Syanindyta AR, Bahry MS, Widiananto PA, Helmi M, Armono HD, Supriadi, Igarashi Y. 2020. The effect of culture media on the number and bioactivity of marine invertebrates associated fungi. Biodiversitas 21: 407-412. Marine ecosystem is rich with microorganisms such as bacteria and fungi either as free-living or in association with macro-organisms. Marine invertebrates provide suitable habitats for fungi by supplying space, food, and other chemicals stuff that in some cases is a reciprocal relationship or called mutualism symbiotic. Some marine invertebrates have interesting activities that are useful for human life such as anticancer, antifungal, and antibacterial. Many reports indicated that the fungal growth and their production of bioactive compounds were highly affected by the media or nutrition. In order to understand the effect of media on the number and bioactivity of the isolates, we collected the samples of marine invertebrates from two locations in Makassar. Invertebrate specimens were collected by hand during SCUBA diving at 3-10 m depths. The fungi were isolated by tapping method either on potato dextrose agar (PDA) or poor marine agar (PMA). The samples were collected from the Samalona water as much as 16 specimens that provided 30 and 18 fungal isolates on PDA and PMA, respectively, while, from the Barrang Cadi water, a total 14 specimens were collected to provide 12 and 3 isolates on PDA and PMA, respectively. All fungi from PMA inhibited the V. harveyi, V. vulnificus, and V. parahaemolyticus with weak, medium, and strong activities, while, the isolates from PDA were mostly not active against the Vibrios. Based on the molecular analyses, the active isolates were identified as Aspergillus flavus, A. oryzae, A. aculeatus, Talaromyces minioluteus, Hypocrea jecorina, Gliomastix murorum, Myrothecium inundatum, and Curvularia avinis. In conclusion, the isolates from PMA showed higher potential as source of antivibrio substances.

A note on centrifugation for improving freshwater invertebrate sample conservation

Sorting of freshwater invertebrate samples is best done while the animals are still alive. However, sorting in the field generally means less overall sampling can be done in the allotted time. Placing samples under cold conditions has been the traditional way to extend the life of the organisms contained within them. In this work, we evaluated whether the addition of a centrifugation step extends the survival time of organisms post-sampling, thus providing more time for sorting. Three salad spinners were tested for their capacity to extract water from samples. Additional observations were made on the compaction of samples due to excessive centrifugation. We conclude that adding a short centrifugation step of 30 seconds prolongs the life of several freshwater invertebrate taxa, including Hydrachnidia, Nematoda and Ostracoda. Furthermore, when fixation of samples in the field is necessary, centrifugation reduces the amount of fixative to be added to the samples to reach a certain concentration. Fixed samples can also be centrifuged, which may be particularly relevant when sampling abroad as inflam-mable liquids are often prohibited on planes. In our experience, centrifuging fixed samples does not compromise the fixed organisms, or their genetic material.

The impacts of hydraulic clamming in shallow water and the importance of incorporating anthropogenic disturbances into habitat assessments

Hydraulic dredging for shellfish is known to create some of the highest levels of disturbance, affecting the benthic microfaunal community and the physical characteristics of the substrate. Properly conducted benthic habitat assessments are complex and time consuming, resulting in assessments not being conducted increasing the uncertainty in post impact studies. Hydraulic dredging for Atlantic surfclams (Spisula soldidissima) took place at Herring Cove, Massachusetts in the winter of 2014–2015 resulting in areas of high impact disturbance of the seafloor. Surveys conducted in the summer of 2015 included hydroacoustics, benthic invertebrate sampling, video, and grain size analysis for the creation of a habitat map of Herring Cove. The four habitats (A–D) identified were a mix of sand, shell, cobble, algae, and eelgrass. Habitat type “D” is a mix of sand, algae and cobble material and occurred at 12 of 18 stations. These 12 stations were distributed across areas of “high” (n = 4), “low” (n = 2), and “no” (n = 6) hydraulic dredge disturbance. Once habitat was accounted for, benthic invertebrate community structure varied significantly (Analysis of similarity; significance level of sample statistic: 0.3%) between areas of “high”, “low” to “no” disturbance. Areas of “low” to “no” dredge track coverage contained high abundances of bivalves, echinoderms, and isopods, whereas highly disturbed areas had highest abundances of polychaetes and oligochaetes. Future mapping efforts, especially surveys with biological components, need to include and quantify the level, type and spatial distribution of anthropogenic alterations. More attention should be given to “reference maps” instead of “baseline maps”. The latter of which omits to acknowledge pre-existing anthropogenic disturbances and has the potential to skew monitoring of restoration and management efforts.