Exploring the underwater life in transitional environments: Benthic foraminifera, ostracods, and dinoflagellate cysts - Biotic trends and EcoQS assessment in the Mar Piccolo of Taranto (Ionian sea, southern Italy).

Coastal areas have historically thrived as centers of human activities due to their resources, economic opportunities, and natural allure. The rapid growth of coastal populations has however brought forth a multitude of challenges to tackle, with pollution emerging as a significant and far-reaching issue. Our study focuses on the Mar Piccolo of Taranto (Ionian Sea, Southern Italy), a lagoon-like coastal basin (separated in two sub-basins) that, since decades, has been heavily affected by human activities and aquaculture, leading to environmental deterioration. Although past studies have looked at environmental conditions in the Mar Piccolo from a chemical perspective, the biological component (e.g., biological indicators) has been mostly neglected. In this study, we firstly aim to examine the distribution and diversity of foraminifera, ostracods, and dinoflagellate cysts in December 2016 and compare our findings with data collected in December 2011. Foraminiferal and ostracod communities exhibit similar patterns in the two sampling campaigns, while the communities of encysted dinoflagellates show differences concerning both densities and diversity. Then, we evaluate the Ecological Quality Status (EcoQS) using ecological indices. While the indices in the inner basin appear to reflect an actual ecological degradation, they yield conflicting results in the outer basin. In the outer basin, indeed, the indices overestimate the EcoQS. This study highlights the potential of these indices for characterizing the EcoQS but emphasizes the need for improvements in their reliability. This research also contributes to a more holistic understanding of environmental condition in the Mar Piccolo and underscores the importance of integrating biological quality elements into ecosystem management and remediation strategies.

Facilitation costs and benefits function simultaneously on stress gradients for animals.

Understanding the variation in species interactions along environmental stress gradients is crucial for making robust ecological predictions about community responses to changing environmental conditions. The facilitation-competition framework has provided a strong basis for predictions (e.g. the stress-gradient hypothesis, SGH), yet the mechanisms behind patterns in animal interactions on stress gradients are poorly explored in particular for mobile animals. Here, we proposed a conceptual framework modelling changes in facilitation costs and benefits along stress gradients and experimentally tested this framework by measuring fitness outcomes of benefactor-beneficiary interactions across resource quality levels. Three arthropod consumer models from a broad array of environmental conditions were used including aquatic detritivores, potato moths and rainforest carrion beetles. We detected a shift to more positive interactions at increasing levels of stress thereby supporting the application of the SGH to mobile animals. While most benefactors paid no significant cost of facilitation, an increase in potato moth beneficiary's growth at high resource stress triggered costs for benefactors. This study is the first to experimentally show that both costs and benefits function simultaneously on stress gradients for animals. The proposed conceptual framework could guide future studies examining species interaction outcomes for both animals and plants in an increasingly stressed world.

Environmental genotoxicity and risk assessment in the Gulf of Riga (Baltic Sea) using fish, bivalves, and crustaceans.

Environmental genotoxicity in the Gulf of Riga was assessed using different bioindicators (fish, clams, and isopods) collected from 14 study stations. Comparison of genotoxicity responses (micronuclei (MN) and nuclear buds (NB)) in blood erythrocytes of herring (Clupea harengus), eelpout (Zoarces viviparous), and flounder (Platichthys flesus) revealed the species- and site-specific differences. For the first time, the analysis of genotoxicity was carried out in gill cells of isopods Saduria entomon. The highest inductions of MN and NB in gill cells of investigated S. entomon and clams (Macoma balthica) were evaluated in specimens from station 111A (offshore zone). In fish, the highest incidences of MN were measured in eelpout and in herring collected in the southern part of Gulf of Riga (station GOR3/41S). Moreover, in the southern coastal area, the assessment of genotoxicity risk (according to micronuclei levels) indicated exceptionally high risk for flounder, eelpout, and clams.

The AmP project: Comparing species on the basis of dynamic energy budget parameters.

We developed new methods for parameter estimation-in-context and, with the help of 125 authors, built the AmP (Add-my-Pet) database of Dynamic Energy Budget (DEB) models, parameters and referenced underlying data for animals, where each species constitutes one database entry. The combination of DEB parameters covers all aspects of energetics throughout the full organism's life cycle, from the start of embryo development to death by aging. The species-specific parameter values capture biodiversity and can now, for the first time, be compared between animals species. An important insight brought by the AmP project is the classification of animal energetics according to a family of related DEB models that is structured on the basis of the mode of metabolic acceleration, which links up with the development of larval stages. We discuss the evolution of metabolism in this context, among animals in general, and ray-finned fish, mollusks and crustaceans in particular. New DEBtool code for estimating DEB parameters from data has been written. AmPtool code for analyzing patterns in parameter values has also been created. A new web-interface supports multiple ways to visualize data, parameters, and implied properties from the entire collection as well as on an entry by entry basis. The DEB models proved to fit data well, the median relative error is only 0.07, for the 1035 animal species at 2018/03/12, including some extinct ones, from all large phyla and all chordate orders, spanning a range of body masses of 16 orders of magnitude. This study is a first step to include evolutionary aspects into parameter estimation, allowing to infer properties of species for which very little is known.

Mutual assessment during ritualized fighting in mantis shrimp (Stomatopoda).

Safe and effective conflict resolution is critical for survival and reproduction. Theoretical models describe how animals resolve conflict by assessing their own and/or their opponent's ability (resource holding potential, RHP), yet experimental tests of these models are often inconclusive. Recent reviews have suggested this uncertainty could be alleviated by using multiple approaches to test assessment models. The mantis shrimp Neogonodactylus bredini presents visual displays and ritualistically exchanges high-force strikes during territorial contests. We tested how N. bredini contest dynamics were explained by any of three assessment models-pure self-assessment, cumulative assessment and mutual assessment-using correlations and a novel, network analysis-based sequential behavioural analysis. We staged dyadic contests over burrow access between competitors matched either randomly or based on body size. In both randomly and size-matched contests, the best metric of RHP was body mass. Burrow residency interacted with mass to predict outcome. Correlations between contest costs and RHP rejected pure self-assessment, but could not fully differentiate between cumulative and mutual assessment. The sequential behavioural analysis ruled out cumulative assessment and supported mutual assessment. Our results demonstrate how multiple analyses provide strong inference to tests of assessment models and illuminate how individual behaviours constitute an assessment strategy.

A big data approach to macrofaunal baseline assessment, monitoring and sustainable exploitation of the seabed.

In this study we produce a standardised dataset for benthic macrofauna and sediments through integration of data (33,198 samples) from 777 grab surveys. The resulting dataset is used to identify spatial and temporal patterns in faunal distribution around the UK, and the role of sediment composition and other explanatory variables in determining such patterns. We show how insight into natural variability afforded by the dataset can be used to improve the sustainability of activities which affect sediment composition, by identifying conditions which should remain favourable for faunal recolonisation. Other big data applications and uses of the dataset are discussed.

Field assessment of the predation risk-food availability trade-off in crab megalopae settlement.

Settlement is a key process for meroplanktonic organisms as it determines distribution of adult populations. Starvation and predation are two of the main mortality causes during this period; therefore, settlement tends to be optimized in microhabitats with high food availability and low predator density. Furthermore, brachyuran megalopae actively select favorable habitats for settlement, via chemical, visual and/or tactile cues. The main objective in this study was to assess the settlement of Metacarcinus edwardsii and Cancer plebejus under different combinations of food availability levels and predator presence. We determined, in the field, which factor is of greater relative importance when choosing a suitable microhabitat for settling. Passive larval collectors were deployed, crossing different scenarios of food availability and predator presence. We also explore if megalopae actively choose predator-free substrates in response to visual and/or chemical cues. We tested the response to combined visual and chemical cues and to each individually. Data was tested using a two-way factorial design ANOVA. In both species, food did not cause significant effect on settlement success, but predator presence did, therefore there was not trade-off in this case and megalopae respond strongly to predation risk by active aversion. Larvae of M. edwardsii responded to chemical and visual cues simultaneously, but there was no response to either cue by itself. Statistically, C. plebejus did not exhibit a differential response to cues, but reacted with a strong similar tendency as M. edwardsii. We concluded that crab megalopae actively select predator-free microhabitat, independently of food availability, using chemical and visual cues combined. The findings in this study highlight the great relevance of predation on the settlement process and recruitment of marine invertebrates with complex life cycles.

Preliminary ecotoxicity assessment of new generation alternative fuels in seawater.

The United States Navy (USN) is currently demonstrating the viability of environmentally sustainable alternative fuels to power its fleet comprised of aircraft and ships. As with any fuel used in a maritime setting, there is potential for introduction into the environment through transport, storage, and spills. However, while alternative fuels are often presumed to be eco-friendly relative to conventional petroleum-based fuels, their environmental fate and effects on marine environments are essentially unknown. Here, standard laboratory-based toxicity experiments were conducted for two alternative fuels, jet fuel derived from Camelina sativa (wild flax) seeds (HRJ5) and diesel fuel derived from algae (HRD76), and two conventional counterparts, jet fuel (JP5) and ship diesel (F76). Initial toxicity tests performed on water-accommodated fractions (WAF) from neat fuels partitioned into seawater, using four standard marine species in acute and chronic/sublethal tests, indicate that the alternative fuels are significantly less toxic to marine organisms.

Sperm Viability Assessment over elapsing time maintained at 2 degrees C of orange mud crab, Scylla olivacea (Herbst, 1796).

The aim of this study was to evaluate how long the fresh sperm maintained at 2 degrees C would be utilized for fishery management. The study was conducted every 2 h to assess the sperm viability of orange mud crab Scylla olivacea. Evaluations were conducted as 3 treatments; T1, T2 and T3. In T1, the live specimens were sacrificed; for T2, only spermatophores were extracted and for T3 spermatophore extraction followed by homogenization to create a sperm suspension. All samples were stored with ice in an insulated box was keep fresh longer at 2 degrees C. The time '0' referred the immediate collection of sperm after the specimen was sacrificed. Spermatophore viability was determined using the sperm suspension by eosin-nigrosin staining method. Sperm viability for the fresh sample at time zero was 97.36 ± 0.53%. Viability of the sperm significantly decreased in the 2nd h in all treatments, T1 was 44.66 ± 0.54 to 4.2 ± 0.22% at 16 and 18th h, T2 was 36.56 ± 0.5 to 2.69 ± 0.06% at the 12 and 14th h and T3 was 33.69 ± 1.26 to 6.4 ± 0.29% at 8 and 10th h. In comparison, T1 showed significantly higher than other treatments (p < 0.05). Extremely low viability percentages were recorded in T3. This study also proved that the time elapse had significant impact on the percentage of viable sperm count.

Increased disease calls for a cost-benefits review of marine reserves.

Marine reserves (or No-Take Zones) are implemented to protect species and habitats, with the aim of restoring a balanced ecosystem. Although the benefits of marine reserves are commonly monitored, there is a lack of insight into the potential detriments of such highly protected waters. High population densities attained within reserves may induce negative impacts such as unfavourable trophic cascades and disease outbreaks. Hence, we investigated the health of lobster populations in the UK's Marine Conservation Zone (MCZ) at Lundy Island. Comparisons were made between the fished, Refuge Zone (RZ) and the un-fished, No-Take Zone (NTZ; marine reserve). We show ostensibly positive effects such as increased lobster abundance and size within the NTZ; however, we also demonstrate apparent negative effects such as increased injury and shell disease. Our findings suggest that robust cost-benefit analyses of marine reserves could improve marine reserve efficacy and subsequent management strategies.

The relative cost of using luminescence for sex and defense: light budgets in cypridinid ostracods.

Luminescent signals can be used by animals for a number of purposes, including courtship and defense, sometimes by the same individual. However, the relative costs of producing these different behaviors are largely unknown. In the marine ostracod Photeros annecohenae, males utilize extracellular luminescence for complex courtship displays, and both males and females luminesce as a predation defense. We compared the relative luminescent output of courtship with that of defensive displays and also with respect to their total luminescent stores. Courtship displays are relatively inexpensive compared with defensive displays, with an average defensive display releasing 50 times more luminescence than the average courtship display. Furthermore, in order to completely exhaust its stores, a male would have to produce 450 typical courtship displays or approximately 10 average defensive displays. Both courtship pulses and defensive displays show first-order decay kinetics, yet courtship pulses decay three times faster than defensive displays, suggesting that there is differential release of the luciferin, luciferase and mucus in order to control the reaction kinetics.

Induced resistance in a brown alga: phlorotannins, genotypic variation and fitness costs for the crustacean herbivore.

In the marine littoral, strong grazing pressure selects for macroalgal defenses such as the constitutive and inductive production of defense metabolites. Induced defenses are expected under spatiotemporally varying grazing pressure and should be triggered by a reliable cue from herbivory, thereby reducing grazing pressure via decreased herbivore preference and/or performance. Although induced resistance has frequently been demonstrated in brown macroalgae, it is yet to be investigated whether induced macroalgal resistance shows genetic variation, a prerequisite for evolutionary responses to selection. In addition, consequences of induced resistance on herbivore performance have rarely been tested while the role of brown algal phlorotannins as inducible defense metabolites remains ambiguous. Using preference bioassays, we tested various cues, e.g., natural grazing, waterborne cues or simulated grazing to induce resistance in the brown alga Fucus vesiculosus. Further, we investigated whether there are induced responses in phlorotannin content, genetic variation in induced resistance or incurred performance costs to the mesoherbivore isopod, Idotea baltica. We found that both direct grazing and waterborne grazing cues decreased the palatability of F. vesiculosus, while increasing the total phlorotannin content. Since the sole presence of the herbivore also increased the total soluble phlorotannins, yet failed to stimulate deterrence, we concluded that phlorotannins alone do not explain increased resistance. Induced resistance varied between algal genotypes and thus showed potential for evolutionary responses to variation in grazing pressure. Induced resistance also incurred performance costs for female I. baltica via reduced egg production. Our results show that the induced resistance of F. vesiculosus decreases grazing pressure by deterring herbivores as well as impairing their performance. Resistance may be induced in advance by waterborne cues and spread effectively throughout the F. vesiculosus belt. Through lowering herbivore performance, induced resistance may also reduce future grazing pressure by decreasing the population growth rate of I. baltica.

Parasites of the pleasure oyster Crassostrea corteziensis cultured in Nayarit, Mexico.

The pleasure oyster Crassostrea corteziensis is collected and cultured in Nayarit on the Pacific coast of Mexico, and the improvement and promotion of its culture are seen as a possible source for the economic development of coastal populations. However, information about the parasite fauna of the pleasure oyster is almost completely lacking. A histopathological survey carried out in two estuaries, Boca del Camichín and Pozo Chino, revealed the presence of hypertrophied gametes, rickettsiales-like prokaryotes (RLPs), the protozoan Perkinsus marinus, a protozoan Nematopsis sp., Ancistrocoma-like ciliates (ALCs), Sphenophrya-like ciliates, a turbellarian Urastoma sp., and encysted crustaceans. In general, prevalence and intensity of parasites were similar in both localities except that ALCs and encysted crustaceans were more prevalent in Pozo Chino than in Boca del Camichín. Perkinsus marinus and RLPs seem to represent a more significant risk for the health of pleasure oysters than do the other parasites, and surveillance and control of these parasites are needed for the development of pleasure oyster culture.

Additive vs non-additive genetic components in lethal cadmium tolerance of Gammarus (Crustacea): novel light on the assessment of the potential for adaptation to contamination.

Questioning the likelihood that populations adapt to contamination is critical for ecotoxicological risk assessment. The appraisal of genetic variance in chemical sensitivities within populations is currently used to evaluate a priori this evolutionary potential. Nevertheless, conclusions from this approach are questionable since non-additive genetic components in chemical tolerance could limit the response of such complex phenotypic traits to selection. Coupling quantitative genetics with ecotoxicology, this study illustrates how the comparison between cadmium sensitivities among Gammarus siblings enabled discrimination between genetic variance components in chemical tolerance. The results revealed that, whereas genetically determined differences in lethal tolerance exist within the studied population, such differences were not significantly heritable since genetic variance mainly relied on non-additive components. Therefore the potential for genetic adaptation to acute Cd stress appeared to be weak. These outcomes are discussed in regard to previous findings for asexual daphnids, which suggest a strong potency of genetic adaptation to environmental contamination, but which contrast with compiled field observations where adaptation is not the rule. Hereafter, we formulate the reconciling hypothesis of a widespread weakness of additive components in tolerance to contaminants, which needs to be further tested to gain insight into the question of the likelihood of adaptation to contamination.

Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatching and survival.

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. Moreover, after removing the chorion of exposed cysts, the concentration of chlorpyrifos in the embryo was lower than that of cysts exposed, what would demonstrate the retention of chlorpyrifos molecules by the shell. Hatching was not severely affected by exposure to the insecticide whereas survival at 44 h of the nauplii exposed to chlorpyrifos was significantly different from the controls. Survival of nauplii hatched from exposed decapsulated cysts was higher than that from those hatched from exposed whole cysts, probably because of the lower vitality of the latter, due to depletion of energy reserves during hatching.

Short-term responses of Oryzias latipes (Pisces: Adrianichthyidae) and Macrobrachium nipponense (Crustacea: Palaemonidae) to municipal and pharmaceutical waste water in Beijing, China: survival, behaviour, biochemical biomarkers.

Whole effluent toxicity was assessed for the fish Oryzias latipes and the prawn Macrobrachium nipponense for 18 h in a dilution series (0-66%) of the inflow and effluent of a municipal waste water treatment plant as well as waste water from a teramycin producing pharmaceutical industry, before, during and after a pilot laboratory purification process. The waste waters caused acute toxicity as measured by inhibition of light emission in the luminiscent bacterium Vibrio qingaiensis sp. nov. (Q67). EROD and aryl hydrocarbon hydroxylase activity in in vitro carp liver-cells showed a dose-dependent toxic response to the municipal waste water. Behavioural responses and time-to-death of fish and prawn, recorded online with the "Multispecies Freshwater Biomonitor" proved to be concentration- and time-dependent sensitive toxicity indicators in both types of waste water. Behaviour changed stepwise from normal activity to (increased or decreased) activity to more time spent on ventilation and finally to increased morbidity at higher concentration and time of exposure. The municipal waste water treatment plant managed to reduce toxicity to bacteria (Q67), prawn and fish. The pharmaceutical waste water treatment process still has to be improved, in order to reduce toxicity for fish and prawn.

Costs of intraspecific and interspecific host sharing in acanthocephalan cystacanths.

Larval helminths often share individual intermediate hosts with other larval worms of the same or different species. In the case of immature acanthocephalans capable of altering the phenotype of their intermediate hosts, the benefits or costs of host sharing can be evaluated in terms of increased or decreased probability of transmission to a suitable definitive host. Competitive interactions among the immature stages of acanthocephalans within the intermediate host could create additional costs of host sharing, however. The effects of intraspecific and interspecific interactions were measured in 3 sympatric species of acanthocephalans exploiting a population of the amphipod Echinogammarus stammeri in the River Brenta, Italy. The strength of interactions was assessed from differences in the size achieved by infective cystacanths in the intermediate host. The size of Pomphorhynchus laevis cystacanths was not correlated with host size, whereas the size of Acanthocephallus clavula and Polymorphus minutus cystacanths increased with host size. Reductions in cystacanth size caused by intraspecific competition were only detected in P. laevis, but may also occur in both A. clavula and P. minutus. When co-occurring in the same amphipod with cystacanths of A. clavula, cystacanths of P. laevis attained a smaller size than when they occurred on their own. This effect was not reciprocal, with the size of A. clavula cystacanths not being affected. This supports earlier suggestions that it is adaptive for A. clavula to associate with P. laevis in amphipod intermediate hosts, with both species going to the same fish definitive hosts. In contrast, cystacanths of P. laevis achieved their largest size when they co-occurred in an amphipod with a cystacanth of P. minutus, which has a different definitive host (i.e. birds). These findings suggest that the net benefits of sharing an intermediate host can only be estimated by taking into account both the effects on transmission success and the consequences for cystacanth development.

Impairment of mysid (Neomysis integer) swimming ability: an environmentally realistic assessment of the impact of cadmium exposure.

Neomysis integer (Crustacea: Mysidacea), a euryhaline member of the hyperbenthos of the upper reaches of European estuaries, has been identified as a suitable animal for assessing the impacts of chemical pollutants on these estuarine regions. In this study, the effect of a 7 day pre-exposure to environmentally relevant concentrations of cadmium (0.5 and 1.0 microg l(-1)) on the swimming behaviour of N. integer was examined using an annular flume. Cadmium speciation at two salinities (1 and 10 per thousand) that dominate these upper estuarine regions was modelled to ensure mysids were exposed to the same concentration of the toxic free-ion at each salinity. There was no significant difference in the swimming behaviour of mysids exposed to the same free-ion cadmium concentration at the two different salinities. At each salinity, exposure to 0.5 microg Cd2+ (aq) l(-1)resulted in fewer mysids moving forward into the current (normal behaviour) at free stream velocities typical of their natural habitat (e.g. 3-9 cm s(-1)) than non cadmium-exposed mysids. At these low current speeds, cadmium-exposed mysids were either able to maintain position or were swept by the current. The same general responses were recorded for mysids exposed to 1.0 microg Cd2+ (aq) l(-1)except that more mysids showed disrupted swimming ability compared with 0.5 microg Cd2+ (aq) l(-1). At higher current speeds (>12 cm s(-1)), current velocity was the dominant factor affecting mysid swimming behaviour and there was no effect of cadmium on mysids maintaining position. Exposure to cadmium also caused significant disruption of the hyperbenthic behaviour of N. integer and more cadmium-exposed individuals were in the water column than control mysids; this result was more variable at 10 per thousand than 1 per thousand. Results indicate that exposure to cadmium concentrations of 0.5 microg Cd2+(aq) l(-1)would result in displacement of N. integer from its optimum region within the estuarine environment. This conclusion would not be achieved from standard LC(50) tests (e.g. 7 day LC50 = 2.95 microg Cd2+ (aq) l(-1)), highlighting the value of behavioural disruption as a sensitive indicator of environmental chemical contamination.

Sealice on salmonids: their biology and control.

Lepeophtheirus salmonis and Caligus elongatus are the two common species of sealice responsible for serious disease problems in salmonid aquaculture. L. salmonis in particular is the most serious parasitic infection on Atlantic salmon farms in the Northern Hemisphere and is the best-known species. This review examines the voluminous literature on the biology and control of sealice and brings together ideas for developing our knowledge of these organisms. Research on the distribution, host range, structure, life cycle, epidemiology, laboratory maintenance, reproductive biology, physiology and pathogenesis is reviewed in depth. The control strategy and economic cost to the industry is discussed. The interactions between wild and cultured salmonids are examined.