Rock Pools Research Articles

An Individual-Based Model of the Red Alga Agarophyton chilense Unravels the Complex Demography of Its Intertidal Stands

Algal demographic models have been developed mainly to study their life cycle evolution or optimize their commercial exploitation. Most commonly, structured-aggregated population models simulate the main life cycle stages considering their fertility, growth and survival. Their coarse resolution results in weak predictive abilities since neglected details may still impact the whole. In our case, we need a model of Agarophyton chilense natural intertidal populations that unravels the complex demography of isomorphic biphasic life cycles and be further used for: (i) introduction of genetics, aimed at studying the evolutionary stability of life cycles, (ii) optimizing commercial exploitation, and (iii) adaptation for other species. Long-term monitoring yield 6,066 individual observations and 40 population observations. For a holistic perspective, we developed an Individual-Based Model (IBM) considering ploidy stage, sex stage, holdfast age and survival, frond size, growth and breakage, fecundity, spore survival, stand biomass, location and season. The IBM was calibrated and validated comparing observed and estimated sizes and abundances of gametophyte males, gametophyte females and tetrasporophytes, stand biomass, haploid:dipoid ratio (known as H:D or G:T), fecundity and recruitment. The IBM replicated well the respective individual and population properties, and processes such as winter competition for light, self-thinning, summer stress from desiccation, frond breakage and re-growth, and different niche occupation by haploids and diploids. Its success depended on simulating with precision details such as the holdfasts’ dynamics. Because “details” often occur for a reduced number of individuals, inferring about them required going beyond statistically significant evidences and integrating these with parameter calibration aimed at maximized model fit. On average, the population was haploid-dominated (H:D > 1). In locations stressed by desiccation, the population was slightly biased toward the diploids and younger individuals due to the superior germination and survival of the diploid sporelings. In permanently submerged rock pools the population was biased toward the haploids and older individuals due to the superior growth and survival of the haploid adults. The IBM application demonstrated that conditional differentiation among ploidy stages was responsible for their differential niche occupation, which, in its turn, has been argued as the driver of the evolutionary stability of isomorphic biphasic life cycles.

Accounting for variation in temperature and oxygen availability when quantifying marine ecosystem metabolism

It is critical to understand how human modifications of Earth’s ecosystems are influencing ecosystem functioning, including net and gross community production (NCP and GCP, respectively) and community respiration (CR). These responses are often estimated by measuring oxygen production in the light (NCP) and consumption in the dark (CR), which can then be combined to estimate GCP. However, the method used to create “dark” conditions—either experimental darkening during the day or taking measurements at night—could result in different estimates of respiration and production, potentially affecting our ability to make integrative predictions. We tested this possibility by measuring oxygen concentrations under daytime ambient light conditions, in darkened tide pools during the day, and during nighttime low tides. We made measurements every 1–3 months over one year in southeastern Alaska. Daytime respiration rates were substantially higher than those measured at night, associated with higher temperature and oxygen levels during the day and leading to major differences in estimates of GCP calculated using daytime versus nighttime measurements. Our results highlight the potential importance of measuring respiration rates during both day and night to account for effects of temperature and oxygen—especially in shallow-water, constrained systems—with implications for understanding the impacts of global change on ecosystem metabolism.

Ecology of Aedes vittatus (Diptera: Culicidae) in rock pools across agroecosystem in Northern Savanna, Nigeria.

This study focuses on modulating dexterity of some ecological variables of Aedes vittatus classically breeding in rocky habitats. The study provides a useful insight into ecological variables that underpin or hinder profuse breeding of Ae. vittatus in rock pools and its probable role in disease transmission. HANNA HI98129 pH/EC/TDS/TEMP meter was used in situ while standard protocols were used to determine other hydro-chemical variables. Aedes vittatus larvae were obtained with soup ladle and modified ladle dippers. D-frame net was used to capture macroinvertebrates while plankton net was used to obtain samples of microalgae. Tadpoles and water turtles were collected with fine mesh invertebrate net. Macrophytes were uprooted and identified at the Herbarium Unit, Department of Botany, Ahmadu Bello University, Zaria. The influence of physicochemical variables was correlated with distribution of Ae. vittatus using Principal Component Analysis. Regression and ANOVA were used to test for association between predictor variables and mosquito abundance and for the difference amongst inselbergs. Linear larval density of Ae. vittatus in rock pools which tapered across Guinea savanna were obtained from twenty-one sites with average density of 139.6 in Sudan savanna. Guinea savanna had an average larval density of 75.5 with lower subsets of moving average densities compared to Sudan savanna. One hundred and sixty-one aquatic insects belonging to four insect orders cohabited rock pools with Ae. vittatus. Toads and frogs' tadpoles were of Bufonidae and Pyxicephalidae families while water turtles belong to Emydidae. pH, TDS (ppm), EC (μs/cm) and alkalinity (mg/l) differed significantly (p<0.05) with the abundance of Ae. vittatus in rock pools. Temperature, depth, water hardness and total suspended solid had direct influence on the distribution of Ae. vittatus in rock pools across sites. Significant positive correlation exists between aquatic insects and abundance of Ae. vittatus. Hydroperiod length, concentration of nitrate and pH were determinants that leverage profuse breeding of Ae. vittatus and survival of rock pool biota. Results revealed that the bearing influence of rock pool variables is inevitable for breeding of Ae. vittatus. A well defined measure of efficacy incorporating indigenous communities for sustained vector control on inselbergs will go a long way in decimating population of Ae. vittatus and limit the risk of spread of yellow fever hitherto areas not thriving.

Faunistic analysis of freshwater zooplankton in small rock pools of Maritime Antarctica

Small water bodies like the rock pools are used as a model system for evolutionary and environmental studies with a growing interest. The zooplankton in the rock pools is a most interesting and promising research object. Although the first papers on Antarctic rock pools were published early in the XX century, these water bodies have been not investigated in detail and comprehensively. The paper aims to review and systematize the knowledge on the diversity of the freshwater zooplankton of the Maritime Antarctica, South Shetland Islands and South Orkney Islands. These organisms include meso- and macro- zooplankton (0.2—20 mm) living in the water and unable to propel themselves against a current, 69 taxa in total. The most diverse of them are 52 taxa of rotifers with 4 taxa identified to the subspecies, 44 — to species, and 4 — to genus level. Crustaceans include 16 taxa (14 identified to the species, 1 — to genus, and 1 — to order); 9 taxa belong to branchiopods, 3 — to ostracods, and 4 — to copepods. One insect species, Parochlus steinenii, is present in the plankton at the larval stage. Summarizing these results, the rock pools of the fairly well studied South Shetland Islands and South Orkney Islands (41 and 46 taxa, respectively) exhibit diversity of living organisms similar to the comparable waterbodies from other parts of the world, while the rest of the region has a much lower diversity (11 taxa). However, this discrepancy is presumably a research artifact because so far, only a few special studies have been done in the Maritime Antarctica. For example, at the Argentine Islands three identified taxa only (2 crustaceans and 1 rotifer) are known with a number of rotifers awaiting identification.

Philosophical Essay on the Traditional Knowledge and Use of Rock Pools in the Brazilian Drylands: Memory and Identity in Temporary Ecosystems

In northeastern Brazil, the drought history has been well documented, reflecting a resilient population with a robust regional identity. Last year, in response to the need to perpetuate water access and reduce scarcity, the Brazilian government implemented a program called the Program One Million Cisterns (P1MC). Considering that the need for water resource perpetuation can impact traditional knowledge transmission between generations, this study aimed to analyze the knowledge regarding rock pools in a small village located in a semiarid region in Brazil. The interviews addressed questions about the traditional knowledge, use, and management of rock pools. The abiotic and biological water variables were collected to establish the population's knowledge status. Our results identified that the use and management of rock pools were reduced after implementing P1MC. Despite the historical relevance of these ecosystems, their use was abandoned by most of the inhabitants, except for domestic use. Therefore, the transmission of traditional knowledge regarding rock pools have decreased between generations, compromising hydric security and representing a serious socio-economic risk for a region characterized by extreme droughts.Keywords: Cyanobacteria Blooms, Drylands zones, Ethno-limnology, Rock pools, Water security Ensaio filosófico sobre o conhecimento tradicional e o uso de tanques de pedra no Semiárido Brasileiro: Memória e identidade em ecossistemas temporáriosRESUMONo nordeste do Brasil, a história da seca foi bem documentada, refletindo uma população resiliente com uma identidade regional robusta. Nos últimos anos, em resposta à necessidade de perpetuar o acesso à água e reduzir a escassez, o governo brasileiro implementou um programa denominado Programa Um Milhão de Cisternas (P1MC). Considerando que a necessidade de perpetuação dos recursos hídricos pode impactar na transmissão do conhecimento tradicional entre gerações, este estudo teve como objetivo analisar o conhecimento sobre os tanques de pedra em uma pequena aldeia localizada em uma região semiárida do Brasil. As entrevistas abordaram questões sobre o conhecimento tradicional, uso e gestão dos tanques de pedra. As variáveis abióticas e biológicas da água foram coletadas para estabelecer o estado de conhecimento da população. Nossos resultados identificaram que o uso e gerenciamento de piscinas naturais foram reduzidos após a implementação do P1MC. Apesar da relevância histórica desses ecossistemas, seu uso foi abandonado pela maioria dos habitantes, exceto para uso doméstico. Portanto, a transmissão do conhecimento tradicional sobre os tanques tem diminuído entre as gerações, comprometendo a segurança hídrica e representando um sério risco socioeconômico para uma região caracterizada por secas extremas.Palavras-chave: Florações de cianobactérias, Semiárido, Etnolimnologia, Tanques de pedra, Segurança hídrica

Determination of the Taxonomic Diversity of the Intertidal Fish Communities on the Pacific Coast of Baja California Sur, M&amp;#233;xico from 2015-2019

The coastal areas of the Baja California peninsula are characterized mainly by rocky areas, where rock pools dominate as important coastal habitats because of the tide cycle, when the water is trapped during the low tide, forming the pools. Environmental parameters like temperature, salinity and dissolved oxygen of the water trapped in the pools are key factors for the flora and fauna that inhabit these areas, particularly during the warmer months when the mean values of these parameters are usually higher than the mean values of the sea surface. The aim of the present study was to determine the variation of the taxonomic diversity of the fish communities that inhabit the rock pools in the common land known as Conquista Agraria in the Pacific coast of Baja California Sur, México, from 2015 to 2019. A total of 59 visual censuses were carried out monthly during the second low tide of the full moon. Temperature, salinity, and dissolved oxygen showed variation throughout the study period, with two distinct seasons (warm and cold), which influenced the taxonomic diversity and taxonomic distinctness of the species recorded in the area. There was a higher diversity in the warmer months (summer) and years (2015 and 2016). In addition, according to the MDS analysis, 2017 and 2018 showed high similarity of species.

Fossils of Blackberry Hill, Wisconsin, USA: the first animals on land, 500 million years ago

Recent discoveries of trackways and trails on ancient tidal flats at Blackberry Hill, Wisconsin, USA, have transformed our understanding of the initial invasion of land, 500 Ma. Huge slug‐like molluscs grazed on microbial mats. Euthycarcinoid (stem myriapod) death traces (mortichnia) suggest that they did not come onto land to feed or breed, but simply to survive; Moon was closer to Earth then, and massive tides stranded animals in tidal pools that gradually dried up.

First report on the distribution of Elysia bangtawaensis Swennen, 1998 in the mangroves of Udupi district, Karnataka

Mangroves are highly threatened tidal forests occurring along estuaries of coastal Karnataka. These forests support a high diversity of flora and fauna, including molluscs and crabs. A recently discovered species of mangrove leaf slug, Elysia bangtawaensis Swennen, 1998 belonging to the superorder Sacoglossa and family Plakobranchidae of Phylum Mollusca, was recorded for the first time in Karnataka from the two mangrove sites, viz . Kodithale and Kannada Kudru of Udupi district. These mangrove leaf slugs were recorded from the tidal pools during post-monsoon and pre-monsoon seasons.

Foundation species loss alters multiple ecosystem functions within temperate tidepool communities

Foundation species, which help maintain habitat and ecosystem functioning, are declining due to anthropogenic impacts. Within the rocky intertidal ecosystem, studies have investigated the effects of foundation species on community structure and some resource fluxes; however, how intertidal foundation species loss will affect multiple facets of ecosystem functioning in concert remains unknown. We studied the direct and indirect effects of foundation species loss of mussels Mytilus californianus and surfgrass Phyllospadix spp. on community structure, fluxes (light, temperature, dissolved oxygen [DO], dissolved inorganic nutrients, pHT), and ecosystem metabolism (net ecosystem calcification [NEC] and net ecosystem production [NEP]) in central Oregon using in situ tide pool manipulations. Surfgrass loss increased microalgae cover, increased average maximum light by 142% and average maximum temperature by 3.8°C, increased DO and pHT values, and indirectly increased NEP and NEC via increased maximum temperature and pHT respectively. Mussel loss increased microalgae cover, increased average maximum light by 5.8% and average maximum temperature by 1.3°C, increased DO and pHT values, and indirectly increased NEP via increased producer cover. Shifts in baseline nutrient concentrations and temperature values from coastal upwelling influenced ecosystem metabolism in pools with intact foundation species. Our results indicate that as communities respond to foundation species loss, ecosystem functioning depends on the dominant community present and biologically or physically driven shifts in biogeochemistry. This study highlights the importance of the connection between community and ecosystem ecology in understanding the magnitude of changes occurring with anthropogenically-driven intertidal foundation species loss.

Pools of resilience

We describe an extreme habitat for scleractinian corals in intertidal rock pools of southeastern Australia. The pools host a small but hardy subset of coral species despite experiencing conditions beyond those documented for corals anywhere in Australia. Understanding mechanisms behind this may improve insights into climate change adaptation in corals.

Spatiotemporal variations in the population dynamics of a few prominent brittle star species (Echinodermata: Ophiuroidea) from the intertidal flat of the Veraval coast, Gujarat, India

The present communication reports the spatiotemporal variation in the population dynamics of three prominent Ophiuroidea species: Amphipholis squamata, Ophiactis savignyi and Ophiocomella sexradia at the rocky intertidal zone at Veraval (21°35’ N, 69°36’ E) Gujarat, off the Arabian Sea. The two sampling areas with different substratum and community structures were investigated from April 2019 to March 2020. Brittle stars were found inhabited in the coralline bed, zoanthid bed, algal holdfast, rock pool crevices and underneath rocks in the studied coastal areas. A. squamata was the most abundant species followed by O. savignyi and O. sexradia at the Veraval coast. The current study described a few remarkable revelations between the patches of coralline algae and Ophiuroidea abundance. Brittle star population revealed major spatial variations between both sampling sites. Cluster analysis and nMDS support population abundance in a seasonal pattern distribution.

Robustness of temperate versus tropical food webs: comparing species trait-based sequential deletions

Loss of species can unleash a cascade of secondary extinctions that cause dramatic changes in the structure and dynamics of food webs. The consequences for the food web depend on the traits of the species that are lost; thus, it is crucial to identify species’ traits associated with secondary extinction risk. Another important issue is to determine where the most vulnerable ecosystems are located. In this study, we aimed to compare the robustness of temperate versus tropical ecosystems to species loss. A total of 34 intertidal rock pools were analysed from a temperate and a tropical region (17 pools in each). Binary food web networks were assembled for each pool depicting who eats whom. Eighteen topological network properties were estimated to compare temperate and tropical webs. Robustness, a measure of network tolerance to species extinction, was assessed. Species loss was simulated in silico using sequential deletion protocols aimed at species that were (1) most connected, (2) least connected, (3) most abundant, and had the largest (4) body mass (mean weight) and (5) size (mean length). Tropical food webs exhibited higher robustness than temperate food webs. Both temperate and tropical food webs were less robust when the removal was directed at the most-connected species, confirming that highly connected species are particularly important in food webs. This study revealed, for the first time, that the positive relationship previously found between robustness and connectance is only confirmed for temperate webs, highlighting the need for more tropical case-studies in general data sets.

Treyarnon bay rock pool

treyarnon bay rock pool Jill Kitchen (bio) Jill Kitchen, poem, prose poem, Treyarnon Bay, Tintagel, Celtic Sea in the picture we are thirteen and barefoot, standing on the black stones that swell out of the beach near treyarnon bay in cornwall. you're looking directly at the camera almost smirking with your doc martens in one hand and i'll bet you're imagining a cigarette a pint and maybe a handsome bloke in the other. i'm looking away into the salt wind and perhaps even farther, missing my home across the sea that i lost only a few months before, two cats and a dog dispersed between neighbors and my sister in new york city. i haven't yet felt roots grow into my soul legs from this island of limescale teapots and narrow hedge-lined country roads the width of one car where i am no longer supposed to roll up my jean cuffs nor wear white socks nor eat french fries with my fingers nor say can't like a new yorker with the short clipped æn sound but i remember everything i've read about merlin and king arthur and believe this sapphire ripple of sea might lead me closer to them. stony ruins lush with the lean of grass at tintagel summon what is magic in me, crystal caves, morgan le fay and guinevere, their voices whispering to me in ocean tongues as you lead me off to the ice cream stand where we buy frozen cider pops and 99p vanilla cones with cadbury flakes while i shiver beneath awkward eighties bangs i will grow out to look less american as the celtic sea catches and flares against the black spill of rock. [End Page 117] Jill Kitchen JILL KITCHEN's work appears or is forthcoming in HAD, Parentheses Journal, the Penn Review, Pidgeonholes, Radar Poetry, Rust & Moth, the Shore, SWWIM, Tahoma Literary Review, West Trestle Review, Whale Road Review, and elsewhere. She lives in Boulder, Colorado, where she can be found roller-skating on the creek path searching for great horned owls. Copyright © 2022 University of North Carolina Wilmington

Determination of the Fish Community Structure of an Intertidal Rocky Zone of the Pacific Coast of Baja California Sur

The intertidal zone (also known as seashore) are transition areas between land and sea, that are greatly influenced by the tide cycle, therefore, environmental parameters, such as temperature and salinity, oscillate according to the periods in which these areas are exposed to air. Intertidal zones are highly diverse, which makes them key ecosystems for the development of sea life (both flora and fauna) exposed to drastic environmental change. The 59 visual censuses campaigns were carried out during the full moon of each month from 2015 to 2019. Temperature, salinity and dissolved oxygen were recorded during each visual census and showed variations between years. Temperature showed two distinct seasons, warm and cold. A total of 14,995 organisms were recorded, belonging to 30 species, 28 genera, 15 families, five orders and one class. Ecological indices like species richness (SR), Shannon-Wiener’s diversity (H') and Fisher’s alpha (α-Fisher) showed significant differences between years, 2015 and 2016 recorded as the most diverse years, while the lowest values were recorded in 2019. Therefore, fish communities of tide pools showed to be highly diverse, with 30 species recording similar relative abundances, and according to the BVI, only 11 species were dominant. Spatio-temporal variations of temperature, salinity and dissolved oxygen were highly correlated to changes in fish community structure, and the dominance of certain species, which are of great importance for the structure and dynamic of the tide pool communities. Therefore, the aim of the present study was to determine the fish community structure of tide pools during the low tide in the intertidal zone of a locality known as El Faro, on the west coast of La Paz, B. C. S., Mexico.

Water as a Divine Mirror in the Poetry of Daud Kamal

In the poetry of Daud Kamal, water figures as an image of mercy, as in the Quran, and as a mirror that reflects a divine hidden presence. The rock pool evokes the memory of Gandhara and other foundational civilizations born in love and creative ferment. Conversely, the images of drought, heat, and dust symbolize a parched spiritual order. The river, a recurring archetypal image in Kamal’s poetry, represents the fluid self that is subsumed into collective identity to become a poetic distillate of history.

Monitoring of small rock pools reveals differential effects of chronic anthropogenic disturbance on birds and mammals in the Calakmul region, southern Mexico

AbstractGreat attention has been drawn to the impacts of habitat deforestation and fragmentation on wildlife species richness. In contrast, much less attention has been paid to assessing the impacts of chronic anthropogenic disturbance on wildlife species composition and behaviour. We focused on natural small rock pools (sartenejas), which concentrate vertebrate activity due to habitat’s water limitation, to assess the impact of chronic anthropogenic disturbance on the species richness, diversity, composition, and behaviour of medium and large-sized birds and mammals in the highly biodiverse forests of Calakmul, southern Mexico. Camera trapping records of fauna using sartenejas within and outside the Calakmul Biosphere Reserve (CBR) showed that there were no effects on species richness, but contrasts emerged when comparing species diversity, composition, and behaviour. These effects differed between birds and mammals and between species: (1) bird diversity was greater outside the CBR, but mammal diversity was greater within and (2) the daily activity patterns of birds differed slightly within and outside the CBR but strongly contrasted in mammals. Our study highlights that even in areas supporting extensive forest cover, small-scale chronic anthropogenic disturbances can have pervasive negative effects on wildlife and that these effects contrast between animal groups.

Weapons or deterrents? Nudibranch molluscs use distinct ecological modes of chemical defence against predators.

Defensive chemicals are used by plants and animals to reduce the risk of predation through different mechanisms, including toxins that cause injury and harm (weapons) and unpalatable or odiferous compounds that prevent attacks (deterrents). However, whether effective defences are both toxins and deterrents, or work in just one modality is often unclear. In this study, our primary aim was to determine whether defensive compounds stored by nudibranch molluscs acted as weapons (in terms of being toxic), deterrents (in terms of being distasteful) or both. Our secondary aim was to investigate the response of different taxa to these defensive compounds. To do this, we identified secondary metabolites in 30 species of nudibranch molluscs and investigated their deterrent properties using antifeedant assays with three taxa: rock pool shrimp, Palaemon serenus, and two fish species: triggerfish Rhinecanthus aculeatus and toadfish Tetractenos hamiltoni. We compared these results to toxicity assays using brine shrimp Artemia sp. and previously published toxicity data with a damselfish Chromis viridis. Overall, we found no clear relationship between palatability and toxicity, but instead classified defensive compounds into the following categories: Class I & II-highly unpalatable and highly toxic; Class I-weakly unpalatable and highly toxic; Class II-highly unpalatable but weakly toxic; WR (weak response)-weakly unpalatable and weakly toxic. We also found eight extracts from six species that did not display activity in any assays indicating they may have very limited chemical defensive mechanisms (NR, no response). We found that the different classes of secondary metabolites were similarly unpalatable to fish and shrimp, except extracts from Phyllidiidae nudibranchs (isonitriles) that were highly unpalatable to shrimp but weakly unpalatable to fish. Our results pave the way towards better understanding how animal chemical defences work against a variety of predators. We highlight the need to disentangle weapons and deterrents in future work on anti-predator defences to better understand the foraging decisions faced by predators, the resultant selection pressures imposed on prey and the evolution of different anti-predator strategies.

Sequestration and Cyanobacterial Diet Preferences in the Opisthobranch Molluscs Dolabrifera nicaraguana and Stylocheilus rickettsi

A multidisciplinary approach was used to assess chemical ecological dietary interactions between marine organisms as a tool to isolate novel ecologically relevant compounds with biotechnological potential. First, laboratory-based feeding preference assays of the sea hareDolabrifera nicaraguana(previously known asD. dolabrifera), an anaspidean mollusc, were conducted by simultaneously offering six food options collected from nearby tidal pools in the Coiba National Park in the Tropical Eastern Pacific of Panama. An evaluation of preferred dietary repertoire revealedD. nicaraguanasignificantly preferred cf.Lyngbyasp. over the cyanobacteriumSymplocasp., green algaChaetomorphasp., and red algaSpyridiasp. A no-choice feeding assay using cf.Lyngbyasp. or green algaCladophorasp. supported this finding. Secondly, we conducted bioactivity-guided fractionation using the preferred food source ofD. nicaraguana, the ‘hair-like” cf.Lyngbyasp. from which we also isolated and elucidated two new depsipeptide compounds, veraguamide M (1) and veraguamide N (2). Veraguamides M (1) and N (2) showedin vitroactivity toward the malaria-causing parasitePlasmodium falciparumwith GI50values of 4.2 and 4.3 μM, respectively, and therapeutic windows of 7.0–8.0 (based on moderate cytotoxicities to mammalian Vero cells with GI50values of 29.3 and 34.1 μM, respectively). Veraguamide N (2) was also active againstLeishmania donovani, the causative agent of visceral leishmaniasis, with a GI50value of 6.9 μM. We then evaluated sequestration of these new compounds byD. nicaraguanaused in the feeding assays and found trace amounts of the dietary sequestered compounds. Finally, we evaluated sequestration of these new compounds by the sea hareStylocheilus rickettsi(previously known asS. striatus) that were grazing on the cf.Lyngbyasp. used in the feeding assays and found both to be sequestered. This study is the first example whereby compounds with significant activity against tropical parasites have been found in both the sea hareS. rickettsiand its cyanobacterial food source. These results suggest that chemical ecological studies involving sea hares and cyanobacteria continue to provide a diverse source of bioactive compounds with biotechnological potential.

Vanishing waters: water chemistry of temporary rock pools of the Western Ghats, India

AbstractThe freshwater rockpools support high endemic biodiversity but are poorly studied habitats in the Western Ghats biodiversity hotspot. These freshwater rock pools are situated on outcrops at various elevations in the Western Ghats and are composed of different bedrocks such as laterite and basalt. We aimed to analyze the water quality, geographical position based differences in the water chemistry and the role of bedrock in determining the water chemistry of the rock pools. Our study showed a wide range of water quality variables such as pH, conductivity, and ionic contents that attributed to the natural variation. We observed a drastic variation in the anions and cations at low elevation pools. Rock type and precipitation are influencing the ionic concentration; for example, Calcium and Bromide could be attributed to the seasonal precipitation and geomorphology. This documentation of physicochemical properties of the Western Ghats rock pools can form a baseline for further detailed studies.

Marine heat waves differentially affect functioning of native (Ostrea edulis) and invasive (Crassostrea [Magallana] gigas) oysters in tidal pools

The frequency and duration of short-term extreme climatic events, such as marine heat waves (MHWs), are increasing worldwide. The rapid onset of MHWs can lead to short-term stress responses in organisms that may have lethal or sub-lethal effects. In addition, increased temperature variability and extremes are predicted to favour and facilitate the spread of non-native species, altering rates of key ecosystem processes and functions. It is possible, however, that compensatory mechanisms, such as increased feeding rates, may enable the maintenance of metabolic functioning and prevent detrimental temperature effects. Using a mesocosm-based approach, we experimentally tested for the effects of MHWs in tidal pools on the mortality, individual length, width and biomass, and respiration rates for both a native oyster, Ostrea edulis, and invasive oyster, Magallana gigas, with or without food supply. No mortality was recorded for either O. edulis or M. gigas for the duration of the four week experiment. Increases in length were greater in O. edulis compared to M. gigas but were not affected by temperature or food supply. Increases in width, however, did not differ between species but were reduced overall in heat wave treatments regardless of food supply. O. edulis gained more biomass than M. gigas in ambient treatments regardless of food supply but, in heat wave treatments, only gained greater biomass than M. gigas at additional levels of food supply. Respiration rates did not reflect changes in temperature or food supply in either species but differed through time, with greater rates post-heat wave in all treatments. Thermal responses of O. edulis and M. gigas to MHWs thus appear to be context dependent and, if food supply is sufficient, O. edulis may be able to maintain its presence in the intertidal. The ability of M. gigas to remain unaffected by fluctuating environmental conditions, however, suggests future resilience of invasive populations to climatic extremes that may result in competitive exclusion and a further decline in native oyster populations. This information is critical for developing effective management plans to ensure the sustainability of natural oyster populations whilst maintaining key ecosystem functioning.