Rock Pools Research Articles

Biogeography of the endosymbiotic dinoflagellates (Symbiodiniaceae) community associated with the brooding coral Favia gravida in the Atlantic Ocean.

Zooxanthellate corals live in symbiosis with phototrophic dinoflagellates of the family Symbiodiniaceae, enabling the host coral to dwell in shallow, nutrient-poor marine waters. The South Atlantic Ocean is characterized by low coral diversity with high levels of endemism. However, little is known about coral–dinoflagellate associations in the region. This study examined the diversity of Symbiodiniaceae associated with the scleractinian coral Favia gravida across its distributional range using the ITS-2 marker. This brooding coral endemic to the South Atlantic can be found across a wide range of latitudes and longitudes, including the Mid-Atlantic islands. Even though it occurs primarily in shallower environments, F. gravida is among the few coral species that live in habitats with extreme environmental conditions (high irradiance, temperature, and turbidity) such as very shallow tide pools. In the present study, we show that F. gravida exhibits some degree of flexibility in its symbiotic association with zooxanthellae across its range. F. gravida associates predominantly with Cladocopium C3 (ITS2 type Symbiodinium C3) but also with Symbiodinium A3, Symbiodinium linucheae (ITS2 type A4), Cladocopium C1, Cladocopium C130, and Fugacium F3. Symbiont diversity varied across biogeographic regions (Symbiodinium A3 and S. linucheae were found in the Tropical Eastern Atlantic, Cladocopium C1 in the Mid-Atlantic, and other subtypes in the Southwestern Atlantic) and was affected by local environmental conditions. In addition, Symbiodiniaceae diversity was highest in a southwestern Atlantic oceanic island (Rocas Atoll). Understanding the relationship between corals and their algal symbionts is critical in determining the factors that control the ecological niches of zooxanthellate corals and their symbionts, and identifying host-symbiont pairs that may be more resistant to environmental changes.

Olfactory discrimination between chemical cues from coastal vegetation in two palaemonid shrimps,Palaemon vulgarisSay, 1818 andP. affinisH. Milne Edwards, 1837 (Decapoda: Caridea: Palaemonidae)

Many decapod crustaceans have highly developed chemosensory systems, with naturally occurring waterborne chemicals used to inform movement and other behavioural processes. I show that two species of intertidal palaemonid shrimps from geographically disparate locations, the North American grass shrimp Palaemon vulgaris (Say, 1818) and the New Zealand tide pool shrimp P. affinis H. Milne Edwards, 1837, possess the ability to discriminate between chemical cues produced by intertidal plants. Both species displayed a variable, but broadly comparable, response to plant odours, showing an attraction to aquatic, emergent species irrespective of taxonomy, and either showing no response or an avoidance to non-aquatic coastal species. While the chemical basis for an attraction or avoidance to these plant species is unclear, the ability to differentiate between plant species could have important implications for the behaviour of these shrimps, assisting them to locate and orient towards structurally complex habitats when visual acuity is limited.

Distribution and density of lobsters in the Brazilian oceanic ecosystem Rocas Atoll

Abstract Lobsters are recognizable faunal elements that play an important role as top predator in the trophic webs in benthic ecosystems and have an economic importance due to the intensive and valuable fishery. In Rocas Atoll (03°51′S 33°48′W) the presence of five species of lobsters in low tide pools was observed by visual census. These were: Enoplometopus antillensis Lütken, 1865; Palinurellus gundlachi Von Martens, 1878; Panulirus argus (Latreille, 1804); Panulirus echinatus Smith, 1869; and Parribacus antarcticus (Lund, 1793). This atoll appears to be dominated by P. echinatus followed by P. argus, P. antarcticus, P. gundlachi and E. antillensis, respectively. We also observed the presence of some potential predators that perhaps feed on lobster species and control these populations in the atoll. This work and future information could help to better understand the variability of lobster diversity and density in this unique atoll.

First Report of <i>Dryophytes japonicus</i> Tadpoles in Saline Environment

The environment is becoming increasingly saline due to global warming and the rise of sea levels. Consequently, species living at low elevations and that are able to demonstrate tolerance to salinity are more likely to adapt to their new environment. Amphibians are especially sensitive to salinisation due to their permeable skin, which makes them osmotically sensitive. Globally, over a hundred amphibian species have demonstrated variable tolerance to salinity, but no such species has been found on the Korean peninsula. We conducted a transect survey in the intertidal zone of Sae Island, Jeju, Republic of Korea for the occurrence of Dryophytes japonicus tadpoles. We also measured salinity, distance to the water line and maximum width for each tidal pool encountered. Our results revealed the presence of D. japonicus tadpoles at all distances from the waterline, in both fresh and brackish water, and independent of the pool maximum width. Salinity and distance to the water line were not found to be of significant importance to the occurrence of the species, and calling males were present at all pools. The highest salinity measured at pools with tadpoles was 9.8 ‰, which is equal to a third of the salinity of the sea surrounding the island. This is the first such record for the species and for the Republic of Korea. Our results also highlight a potential for tolerance to salinisation of the environment in relation to climate change.

Biodiversity of benthic filamentous cyanobacteria in tropical marine environments of Bahia State, Northeastern Brazil

This study aimed to better understand the biodiversity and ecological aspects of benthic filamentous cyanobacteria along the coast of an extensive Brazilian tropical region with underestimated biodiversity. We collected samples between 2010 and 2012 in 24 areas along the coast of the State of Bahia, Northeastern Brazil. We analyzed biodiversity, life form, and spatial distribution of filamentous cyanobacteria on various marine substrata. The intertidal area was divided into three microhabitats according to hydrodynamics: tidal pools, protected reef region, and front reef region. Thirty-two taxa were identified and Oscillatoriales showed the highest biodiversity (16 taxa), followed by Nostocales (9), Synechoccocales (5) and Spirulinales (2). We reported 22 new references to Bahia State. Twenty-two taxa occurred only in one beach, and Symploca cf. hydnoides Gomont was the only widely distributed along the coast of Bahia. Epilithic (21 taxa) and epiphytic (15) showed the greatest species richness. Only two species presented epizoic life form. We observed the highest species richness in the protected reef region (17 taxa). We found eleven and eight taxa in the tidal pool and supralittoral zone, respectively. No cyanobacteria were found in the front reef region, an area with high hydrodynamics. This research presented many taxa in common with previous studies on cyanobacterial diversity developed in other tropical regions around the globe. The great biodiversity and new records reported in this study highlight the need of further surveys in tropical coastal environments, areas still underexplored in terms of biodiversity of cyanobacteria.

Evaluation of the potential of Chlorella sp. HS2, an algal isolate from a tidal rock pool, as an industrial algal crop under a wide range of abiotic conditions

While the screening and development of robust algal crops have mostly focused on determining strains that exhibit the highest possible yields of biomass or desirable biomolecules, these criteria do not necessarily lead to finding algal strains with high tolerance to varying outdoor cultivation conditions. Herein, we report Chlorella sp. HS2 isolated from a tidal rock pool nearby a local coastal waterfall that presumably experienced fluctuations in salinity, pH, and temperature. Compared to two reference strains, Chlorella sp. HS2 exhibited relatively high tolerance to a wide range of salinity (0–5% (w/v) of supplemental NaCl), pH (3.0–10.5), and temperature (14–46 °C) with substantially high biomass accumulation. While the supplementation of either gaseous CO2 or sodium bicarbonate enhanced algal growth, the mixotrophic and heterotrophic cultivations of Chlorella sp. HS2 further indicated its propensity to grow favorably under the presence of organic carbon sources. Subsequent PBR cultivation of Chlorella sp. HS2 under optimal light and/or temperature conditions suggested the highest specific growth rate during mixotrophy, while the analyses of the harvested biomass identified palmitate, oleate, and linoleate as major fatty acid methyl esters, and lutein and s-carotene as predominant carotenoids. Substantially, high growth rates of Chlorella sp. HS2 under a wide range of abiotic conditions and different trophic modes with favorable biochemical composition thus strongly support our algal isolate as a robust and reliable algal crop that can be deployed to achieve high production of commercially important biomolecules and to incorporate simultaneous treatment of wastewater or CO2-replete flue gas into algal cultivation.

Taxonomical and bionomical notes on the Sicilian endemic water beetle Ochthebius (Cobalius) biltoni (Coleoptera: Hydraenidae)

Ochthebius (Cobalius) biltoni Jäch & Delgado, 2017 is the most recently described species of Italian water beetles of the family Hydraenidae (Jäch & Delgado 2017). Most of the new hydraenid species recently discovered from southern Europe were found in two quite different aquatic habitats, as small streams in mountain areas, and hypersaline coastal habitats. These aquatic ecosystems evidently represent a not still exhausted source of unknown biodiversity in Europe (Jäch 1989, 1997; Audisio et al. 1996, 2010; Trizzino et al. 2011, 2013a, 2013b; Sabatelli et al. 2016; Jäch & Delgado 2017). Ochthebius (Cobalius) biltoni was described on a male collected (2012) along a rocky shore of Cefalù (NW Sicily), and on a few specimens collected in marine rock pools of the SW Sicily (Jäch & Delgado 2017). Several vain attempts were made (2014-2017) to collect again this species at the type locality, suggesting that O. biltoni represents an exceedingly rare and elusive taxon. The present note is aimed to add information on the poorly known biology and taxonomy of this species, basing on material and data collected during recent expeditions to Sicily. Taxonomy. Ochthebius (Cobalius) biltoni represents the smallest (1.4- 1.6 mm long) Mediterranean species of the subgenus Cobalius, and it is also characterized by a series of specific traits (Fig. 1) not evidenced by Jäch & Delgado (2017): the convex posterior portion of elytra, more convex and more abruptly sloping posteriad than in all other Cobalius; the series of large sharp projections along the outer elytral sides; the nearly cylindrical, narrow, and strongly pointed distad last maxillary palpomeres. The male genitalia of this species are not markedly distinguished from other species of Cobalius (Fig. 2 in Jäch & Delgado 2017). The apical lobe is dilated distad, recalling the condition presented by O. (Cobalius) celatus Jäch, 1989. Genetically, Ochthebius (C.) biltoni, recently analyzed by our research team, is confirmed to occupy an isolated position, external to most other known members of its subgenus. An upcoming paper (Sabatelli et al. unp. data) is aimed at summarizing the genetic relationships among Cobalius. Ecology. All specimens of O. biltoni from SW Sicily were found in small (15-40 cm wide) and shallow (2-5 cm depth) marine rockpools with a yellowish- brown bottom layer of Diatoms, placed along wide rocky calcareous platforms surrounding the littoral road between Mazara del Vallo and Sciacca, about 2 m above the sea level (Fig. 2). In the same localities, larger and deeper rock pools resulted to be only inhabited by other widespread sympatric species of Ochthebius. Amog these, O. quadricollis and O. subinteger were collected in company of O. biltoni. Our observations allow us to hypothesize that adults and larvae of this species are present throughout the year, even if they are more active in Autumn and Spring. Conservation. Ochthebius (Cobalius) biltoni is an exceedingly rare taxon, exhibiting selective habitat preferences. Despite the poor available data, it is likely that this species represents a taxon with a small and ecologically fragmented geographic range, and poor connectivity between the different populations. Most marine rock pools areas where the species could potentially be present at least in the past in Sicily have been, and continue to be, exposed to severe anthropogenic pressures, including the increasing impact of coastal urbanization, and the frequent use of marine rock pools as trash wastes by tourists. This species therefore matches most criteria necessary for being considered in the IUCN risk Category EN [IUCN criteria B2 (a,b,c); see IUCN, 2013].

Observations of water-flea Daphnia magna and avian fecalia in rock pools: is traditional natural history reporting still relevant for science?

ABSTRACTUnexpected observation of freshwater invertebrate Daphnia magna in temporary rock pools on a small island off the Norwegian Atlantic coast confirms colonising ability, mediated through avian dispersal. Robust diapausal eggs of D. magna pass the gut of migrating geese and subsequently hatch in environments where such waterfowl forage and rest along migrating routes. The incubation experiment demonstrates that decomposing fecalia of geese constitute sufficient feed to support developing populations of D. magna in experimental oligotrophic conditions. The findings also show that D. magna is highly adapted for colonisation of temporary pools north of the Arctic Polar Circle, with excellent tolerance to low temperatures. Discussion part I relates the findings to published evidence on avian transport of invertebrate propagules, such as correlations between migration patterns of waterfowl and geographical patterns of aquatic invertebrate diversity. Discussion part II reflects on academic cultures, epistemological aspects of natural history reporting, the presence of a whale cadaver as an ecological indicator and the relevance of simple observation as a starting point for further discourse.

Nutrient availability affects the prevalence of a microsporidian parasite.

Defining the relationship between nutrients and parasitism is complicated by shifts in host physiology and population density, which can both mediate the effects of host diet on parasites and vice versa. We examined the relationship between nutrient availability and an abundant parasite capable of both horizontal and vertical transmission (Hamiltosporidium tvaerminnensis) of a planktonic crustacean, Daphnia magna, in rock pools on Baltic Sea Skerry islands. We found that the relative availability of nutrients directly affected infection prevalence; parasite prevalence was higher in pools with higher particulate N:P ratios. Infection prevalence was not related to Daphnia population densities. A complementary experiment that examined host responses to an N:P gradient in mesocosms indicated that high N:P ratios can increase spore load in the hosts. We surmise that high N:P food increases Daphnia feeding rate, which increases their contact with parasite spores and leads to higher prevalence and more intense infections. We found no direct evidence that parasite-induced changes in host nutrient use affected nutrient dynamics in pools. However, the relationship between diet N:P and the parasite's prevalence and load is consistent with previously documented patterns of this parasite's effect on host nutrient use. Taken together, this study suggests that high N:P ratios in food may benefit the parasite in multiple ways and could create environments that favour horizontal transmission over vertical transmission for parasites capable of both transmission routes. If so, nutrient limitation could have long-term consequences for host-parasite evolution.

Area-Independent Effects of Water-Retaining Features on Intertidal Biodiversity on Eco-Engineered Seawalls in the Tropics

Over the last decade there has been a global effort to eco-engineer urban artificial shorelines with the aim of increasing their biodiversity and extending their conservation value. One of the most common and viable eco-engineering approaches on seawalls is to use enhancement features that increase habitat structural complexity, including concrete tiles moulded with complex designs and precast “flowerpots” that create artificial rock pools. Increases in species diversity in pits and pools due to microhabitat conditions (water retention, shade, protection from waves, and/or biotic refugia) are often reported, but these results can be confounded by differences in surface area sampled. In this study, we fabricated three tile types (n=10): covered tile (grooved tile with a cover to retain water), uncovered tile (same grooved tile but without a cover) and granite control. We tested the effect of these tile types on species richness (S), total individual abundance (N), and community composition. All tiles were installed at 0.5 m above chart datum along seawalls surrounding two island sites (Pulau Hantu and Kusu Island) south of Singapore mainland. The colonising assemblages were sampled after eight months. Consistent with previous studies, mean S was significantly greater on covered tiles compared to the uncovered and granite tiles. While it is implied in much of the eco-engineering literature that this pattern results from greater niche availability allotted by microhabitat conditions, we further investigated whether there was an underlying species-individual relationship to determine whether increases in S could have simply resulted from covered tiles supporting greater N (i.e. increasing the probability of detecting more species despite a constant area). The species-individual relationship was positive, suggesting that multiple mechanisms are at play, and that biodiversity enhancements may in some instances operate simply by increasing the abundance of individuals, even when microhabitat availability is unchanged. This finding underscores the importance of testing mechanism in eco-engineering studies and highlights ongoing mechanistic uncertainties that should be addressed to inform the design of more biodiverse seawalls and urban marine environments.

Present and future invasion perspectives of an alien shrimp in South Atlantic coastal waters: an experimental assessment of functional biomarkers and thermal tolerance

Climate change, particularly ocean warming, is thought to benefit the spread of invasive species due to their increased tolerance to temperature fluctuations as compared to native species. The physiological tolerance of invasive species as a potential mechanism driving invasion success is therefore a subject that merits further study. Specifically, we need to adequately evaluate the potential of species invasions under changing environmental conditions, so that adequate preventive measures can be taken to minimize any impacts on coastal ecosystems. Here, we experimentally evaluated the physiological responses of a recent invader in the Southern Atlantic, the shrimp Lysmata lipkei, under a warming ocean scenario. Adult shrimps were collected from rocky shores in southeastern Brazil and subjected to experimental trials under a control and a + 3 °C scenario. Molecular biomarkers (in gills and muscle), upper thermal limits, acclimation response ratios, thermal safety margins, mortality rates, estimates of body condition and energy reserves were measured over 1 month. Results suggest that higher temperatures elicit physiological adjustments at the molecular level, underpinning a high thermal tolerance. In addition, results indicated substantial acclimation capacity, with no evidence of decreased performance under an ocean-warming scenario. Thermal safety margins were low for shrimp from intertidal rock pools but high for shrimp from subtidal habitats. We conclude that the thermal tolerance of this shrimp species may favor its ongoing invasion along the Southwestern Atlantic Ocean, mainly in subtidal habitats, both under present and future thermal conditions.

The Purple Sea Urchin Strongylocentrotus purpuratus Demonstrates a Compartmentalization of Gut Bacterial Microbiota, Predictive Functional Attributes, and Taxonomic Co-Occurrence.

The sea urchin Strongylocentrotus purpuratus (order Camarodonta, family Strongylocentrotidae) can be found dominating low intertidal pool biomass on the southern coast of Oregon, USA. In this case study, three adult sea urchins were collected from their shared intertidal pool, and the bacteriome of their pharynx, gut tissue, and gut digesta, including their tide pool water and algae, was determined using targeted high-throughput sequencing (HTS) of the 16S rRNA genes and bioinformatics tools. Overall, the gut tissue demonstrated Arcobacter and Sulfurimonas (Epsilonproteobacteria) to be abundant, whereas the gut digesta was dominated by Psychromonas (Gammaproteobacteria), Propionigenium (Fusobacteria), and Flavobacteriales (Bacteroidetes). Alpha and beta diversity analyses indicated low species richness and distinct microbial communities comprising the gut tissue and digesta, while the pharynx tissue had higher richness, more closely resembling the water microbiota. Predicted functional profiles showed Kyoto Encyclopedia of Genes and Genomes (KEGG) Level-2 categories of energy metabolism, membrane transport, cell motility, and signal transduction in the gut tissue, and the gut digesta represented amino acid, carbohydrate, vitamin and cofactor metabolisms, and replication and repair. Co-occurrence network analysis showed the potential relationships and key taxa, such as the highly abundant Arcobacter and Propionigenium, influencing population patterns and taxonomic organization between the gut tissue and digesta. These results demonstrate a trend of microbial community integration, allocation, predicted metabolic roles, and taxonomic co-occurrence patterns in the S. purpuratus gut ecosystem.

Acidosis Maintains the Function of Brain Mitochondria in Hypoxia-Tolerant Triplefin Fish: A Strategy to Survive Acute Hypoxic Exposure?

The vertebrate brain is generally very sensitive to acidosis, so a hypoxia-induced decrease in pH is likely to have an effect on brain mitochondria (mt). Mitochondrial respiration (JO2) is required to generate an electrical gradient (ΔΨm) and a pH gradient to power ATP synthesis, yet the impact of pH modulation on brain mt function remains largely unexplored. As intertidal fishes within rock pools routinely experience hypoxia and reoxygenation, they would most likely experience changes in cellular pH. We hence compared four New Zealand triplefin fish species ranging from intertidal hypoxia-tolerant species (HTS) to subtidal hypoxia-sensitive species (HSS). We predicted that HTS would tolerate acidosis better than HSS in terms of sustaining mt structure and function. Using respirometers coupled to fluorimeters and pH electrodes, we titrated lactic-acid to decrease the pH of the media, and simultaneously recorded JO2, ΔΨm, and H+ buffering capacities within permeabilized brain and swelling of mt isolated from non-permeabilized brains. We then measured ATP synthesis rates in the most HTS (Bellapiscus medius) and the HSS (Forsterygion varium) at pH 7.25 and 6.65. Mitochondria from HTS brain did have greater H+ buffering capacities than HSS mt (∼10 mU pH.mgprotein-1). HTS mt swelled by 40% when exposed to a decrease of 1.5 pH units, and JO2 was depressed by up to 15% in HTS. However, HTS were able to maintain ΔΨm near -120 mV. Estimates of work, in terms of charges moved across the mt inner-membrane, suggested that with acidosis, HTS mt may in part harness extra-mt H+ to maintain ΔΨm, and could therefore support ATP production. This was confirmed with elevated ATP synthesis rates and enhanced P:O ratios at pH 6.65 relative to pH 7.25. In contrast, mt volumes and ΔΨm decreased downward pH 6.9 in HSS mt and paradoxically, JO2 increased (∼25%) but ATP synthesis and P:O ratios were depressed at pH 6.65. This indicates a loss of coupling in the HSS with acidosis. Overall, the mt of these intertidal fish have adaptations that enhance ATP synthesis efficiency under acidic conditions such as those that occur in hypoxic or reoxygenated brain.

New record of the Crenimugil crenilabis (Forsskål, 1775) (Mugiliformes: Mugilidae) from Korea, as revealed by mitochondrial DNA barcoding

Crenimugil crenilabis (Forsskål 1775) is a fish species newly identified with molecular analysis and reported in Korea for the first time. A single specimen of C. crenilabis was collected from a tidal pool on the southern coast of Jeju Island, Korea in August 2018. This species is characterized by several rows of papillae on both lips, no notch in the mouth corner, the presence of 36 lateral-line scales, and 24 vertebrae. The present specimen is morphologically similar to another seven mugilid species reported in Korea, but mitochondrial DNA COI gene analysis revealed that it is almost identical to C. crenilabis, sharing 98.9–99.3% identity, compared with 75.9–90.3% identity with other species. It’s newly proposed Korean names are ‘Dol-gi-ip-sung-eo-sok’ for the genus and ‘Dol-gi-ip-sung-eo’ for the species.

Corrigendum to: Size, depth and position affect the diversity and structure of rock pool communities in an urban estuary

Rock pools provide a range of ecological niches that can support diverse assemblages on rocky shores. As intertidal shores are increasingly lost to developments, understanding the drivers of diversity in rock pools is important for the conservation and construction of these key habitats. In this study we investigated relationships between physical characteristics of rock pools and their biota in an urban estuary. We sampled the biota every 6 weeks for 1 year at sites in the inner and outer zones of Sydney Harbour. In the well-flushed and exposed outer zone, sessile and mobile taxa richness was positively related to rock pool width, whereas only mobile taxa richness was related to depth and volume. In the more urbanised and less exposed inner zone, mobile taxa richness was positively related to rock pool width and volume. In both zones, sessile taxa richness decreased with increasing height on shore. Our results suggest that the biodiversity of intertidal rock pools varies depending on their position in Sydney Harbour and the available species pool. Therefore, restoration efforts should consider rock pool size parameters and local environmental conditions, including location, so designs can be optimised to maximise species diversity in these pools.

Taxonomic Distinctness of the Intertidal Fish Community on the Pacific Coast of Baja California Sur, México

The intertidal zone is a complex coastal area exposed to a wide variety of environmental factors. During low tide, rocky pools are exposed to air for several hours throughout the day, and environmental conditions such as temperature and salinity are highly variable. Fish communities that inhabit these tide pools are also exposed to environmental variability; therefore it is important to look at fish community structure in relation to important environmental factors such as temperature, salinity and dissolved oxygen on tide pools during spring tides, time of greater exposure to air. Therefore, the aim of the present study was to analyze the variation of the taxonomic distinctness of intertidal fish communities considering temperature, salinity and dissolved oxygen of the water that remains trapped in the tide pools during low tide. Visual census surveys were carried out monthly, from January to December 2015, in the intertidal zone of El Faro during spring tides on full moon days, when fluctuations of environmental variables are significant. Total extension of the census surveys was 156 × 5 m (780 m2). A total of 145 tide pools were sampled and divided in three groups (small, medium and large) according to size and depths that ranged from 20 to 45 cm. Temperature, salinity and dissolved oxygen fluctuate throughout the year of study. Thermal difference between open ocean and tide pools ranged from 3.5°C to 4.5°C. A total of 3757 organisms from 22 species, 12 families, four orders and one class were recorded. When comparing taxonomic distinctness and average taxonomic distinctness between months and tide pools of different sizes, values fell within the confidence intervals in the tunnel and were located close to the mean.

Ecology of Preimaginal Culicine Mosquitoes in Rock Pools on Inselbergs Within Kaduna State, Nigeria

Ecological investigations were conducted between June and October 2013 on the species composition of culicine mosquitoes breeding in discrete rock pool habitats and chemistry of their microhabitats on inselbergs within Kaduna State, Nigeria. Standard soup ladle dipper (0.105L capacity) was used to obtain representative samples of preimaginal stages of mosquito into plastic bowls. HANNA HI98129 pH/EC/TDS/TEMP meter was used to determine habitats' physicochemical parameters in situ. Habitats' turbidity, alkalinity, total suspended solids, total hardness, Chemical oxygen demand, phosphate and nitrate levels were determined following standard laboratory protocols. Fully developed (4th instar) larvae were preserved with 70% ethanol in labelled specimen bottles while larvae in their lower instars were nurtured on baker's yeast diet in the laboratory, prior to preservation. Mosquitoes were identified microscopically to species by means of pictorial morphological keys. Data were analysed by ANOVA, Pearson correlation and principal component analyses. A total of 269 (69.69%) of the 386 rock pools examined were positive with culicine mosquitoes, yielding 31691 larvae belonging to seven species. These included 30366 (95.97%) Aedes vittatus, 266 (0.84%) Culex albiventris, 105 (0.33%) Culex horridus, 241 (0.76%) Culex macfiei, 139 (0.44%) Culex pipiens pipiens, 523 (1.65%) Culex perfidiosus, 1 (0.003%) Culex simpsoni and 1 (0.003%) Culex tigripes. The mosquitoes bred as sole, double, triple and quadruple conspecific, heterospecific, congeneric and heterogeneric combinations. Specific ranges of breeding habitats' parameters were depths (0.4-65cm), surface areas (1.5-1970m 2 ), temperatures (22.8-36.5°C), pH(7.05-12.69), TDS (0-276ppm), EC (0-572µscm -1 ), TSS (10-150mgL -1 ), turbidity (1.97-178NTU), hardness (30.3-545.4 mgL -1 ), COD (80-480mgL -1 ), PO 4 3- (mgL -1 ), NO 3 - (8.5- 109.4 mgL -1 ) and alkalinity (2-111mgL -1 ). Water temperature and hardness were determinants of spatial distribution of mosquitoes in the rock pools. TDS, EC and akalinity significantly correlate with mosquito larval abundance in rock pools (P<0.001). The study observed widespread breeding of noxious mosquito vectors of diseases in rock pools throughout the State and recommends their targeted control in situ.

Integrative taxonomy widens our knowledge of the diversity, distribution and biology of the genus Plakina (Homosclerophorida: Plakinidae)

Despite the evolutionary significance of Homoscleromorpha, their diversity and biology are largely unknown. Here we integrate data of morphology, cytology, microbiology, ecology, reproduction, and mitochondrial cox-1 and cob gene sequences to resolve a complex of sympatric species of Plakina in South-eastern Brazil. All datasets congruently supported the delimitation of three species, two of which are new to science. Plakina coerulea has its distribution extended from one locality to over 2360 km wide. Plakina cabofriense, sp. nov. also occurs in North-eastern Brazil. Plakina cyanorosea, sp. nov. occurs only in a single, small tide pool and may be critically endangered. Plakina cyanorosea, sp. nov. produces conspicuous, abundant larvae useful for laboratory investigations. A thin, bright orange organic coat covers some spicules of P. cabofriense, sp. nov. and P. cyanorosea, sp. nov. The three Plakina species harbour diverse microbial symbiont communities, including previously unknown morphologies. Molecular phylogenies and barcoding gaps based on cox-1 and cob sequences supported that each species is monophyletic and distinct from other congeners. The genus Plakina is paraphyletic and strongly needs redefinition. The integrative approach provides new data that widens our knowledge of Homoscleromorpha diversity, distribution and biology.

Size, depth and position affect the diversity and structure of rock pool communities in an urban estuary

Rock pools provide a range of ecological niches that can support diverse assemblages on rocky shores. As intertidal shores are increasingly lost to developments, understanding the drivers of diversity in rock pools is important for the conservation and construction of these key habitats. In this study we investigated relationships between physical characteristics of rock pools and their biota in an urban estuary. We sampled the biota every 6 weeks for 1 year at sites in the inner and outer zones of Sydney Harbour. In the well-flushed and exposed outer zone, sessile and mobile taxa richness was positively related to rock pool width, whereas only mobile taxa richness was related to depth and volume. In the more urbanised and less exposed inner zone, mobile taxa richness was positively related to rock pool width and volume. In both zones, sessile taxa richness decreased with increasing height on shore. Our results suggest that the biodiversity of intertidal rock pools varies depending on their position in Sydney Harbour and the available species pool. Therefore, restoration efforts should consider rock pool size parameters and local environmental conditions, including location, so designs can be optimised to maximise species diversity in these pools.

Chemical predator signals induce metabolic suppression in rock goby (Gobius paganellus).

In nature, a multitude of both abiotic and biotic stressors influence organisms with regard to their overall fitness. Stress responses that finally impair normal biological functions may ultimately result in consequences for whole populations. This study focused on the metabolic response of the intertidal rock pool fish Gobius paganellus towards simulated predation risk. Individuals were exposed to a mixture of skin extracts from conspecifics and chemical alarm cues from a top predator, Octopus vulgaris. Oxygen consumption rates of single fish were measured to establish standard (SMR) and routine metabolic rates (RMR) of G. paganellus, and to address the direct response towards simulated predation risk, compared to handling and light stress. The SMR of G. paganellus (0.0301 ± 0.0081 mg O2 h-1 g-1 WW) was significantly lower than the RMR (0.0409 ± 0.0078 mg O2 h-1 g-1 WW). In contrast to increased respiration due to handling and light stress, the exposure to chemical predation cues induced a significant reduction in oxygen consumption rates (0.0297 ± 0.0077 mg O2 h-1 g-1 WW). This metabolic suppression was interpreted as a result of the stereotypic freezing behaviour as antipredator response of gobiid fish. Results underline the importance of biotic interactions in environmental stress assessments and predation as a biotic factor that will provide more realistic scenarios when addressing stress impacts in tidal rock pool organisms.