Spatial variability of macrozoobenthic community and trophic structure of a subtropical lagoon on southeastern Brazil's Atlantic coast

The objective of this study was to investigate the macrobenthic community of two compartments of the Maricá-Guarapina lagoon system, along the coast of Rio de Janeiro, Brazil, in relation to its abiotic sediment factors. An additional discrimination between sites was made, wherever the macrophyte Typha domingensis was found. This vegetation supposedly represents a potentially important food source for consumers. Furthermore, the trophic pathways were analyzed functionally by means of stable isotope analysis to assess the role of organic matter sources for consumers in the study area. In conclusion, the results showed differences between abiotic features in the compartments of the lagoon system, which, although they have affected the different species' distribution, have led to a homogeneous low-diversity system. Macrozoobenthic species tend to change with increasing distance from the sea, with a slightly different distribution in the two compartments. The macrophyte T. domingensis did not exercise any great influence on the biotic distribution and was not the main food source for consumers in the lagoon system, where, instead, sedimentary organic matter and macrophyte detritus also seem to play an important role in the trophic web.O objetivo deste trabalho foi estudar a comunidade macrobentônica em dois compartimentos do sistema lagunar Maricá-Guarapina, situado na costa sudeste do Brazil, relacionando com fatores abióticos do sedimento. Adicionalmente, foi feita uma discriminação entre locais com e sem a presença da macrofita Thypha dominguensis, que supostamente representa uma importante fonte alimentar para os consumidores dos sistemas lagunares. A contribuição das macrofitas e outras fontes primárias de alimento para a rede trófica local foi investigada através do método das análises isotópicas. In conclusão, os resultados obtidos mostraram que os fatores abióticos diferiram pouco entre os compartimentos estudados, embora pareçam influenciar a distribuição do macrobentos local, que se caracteriza por uma baixa diversidade específica. As espécies do macrobentos tendem a mudar com o distanciamento do canal de conexão com o mar, existindo pouca diferença na estrutura da comunidade nos dois compartimentos. Igualmente, a presença da macrófita não influenciou a distribuição do macrobentos e os resultados da análise isotópica indicaram que a referida macrófita não representa fonte alimentar importante para os consumidores locais. Por sua vez, a matéria orgânica sedimentar e detritos de macrófitas parecem exercer um papel importante na rede trófica desse sistema lagunar

Spatial variability of macrozoobenthic community and trophic structure of a subtropical lagoon on southeastern Brazil's Atlantic coast

The objective of this study was to investigate the macrobenthic community of two compartments of the Maricá-Guarapina lagoon system, along the coast of Rio de Janeiro, Brazil, in relation to its abiotic sediment factors. An additional discrimination between sites was made, wherever the macrophyte Typha domingensis was found. This vegetation supposedly represents a potentially important food source for consumers. Furthermore, the trophic pathways were analyzed functionally by means of stable isotope analysis to assess the role of organic matter sources for consumers in the study area. In conclusion, the results showed differences between abiotic features in the compartments of the lagoon system, which, although they have affected the different species' distribution, have led to a homogeneous low-diversity system. Macrozoobenthic species tend to change with increasing distance from the sea, with a slightly different distribution in the two compartments. The macrophyte T. domingensis did not exercise any great influence on the biotic distribution and was not the main food source for consumers in the lagoon system, where, instead, sedimentary organic matter and macrophyte detritus also seem to play an important role in the trophic web

Energy metabolism and cellular homeostasis trade-offs provide the basis for a new type of sensitivity to ocean acidification in a marine polychaete at a high-CO2 vent: adenylate and phosphagen energy pools versus carbonic anhydrase

Species distributions and ecology can often be explained by their physiological sensitivity to environmental conditions. Whilst we have a relatively good understanding of how these are shaped by temperature, for other emerging drivers, such as PCO2 we know relatively little. The marine polychaete Sabella spallanzanii increases its metabolic rate when exposed to high PCO2 conditions and remains absent from the CO2 vent of Ischia. To understand new possible pathways of sensitivity to CO2 in marine ectotherms, we examined the metabolic plasticity of S. spallanzanii exposed in situ to elevated PCO2 by measuring fundamental metabolite and carbonic anhydrase concentrations. We show that whilst this species can survive elevated PCO2 conditions in the short term, and exhibits an increase in energy metabolism, this is accompanied by a significant decrease in carbonic anhydrase concentration. These homeostatic changes are unlikely to be sustainable in the longer term, indicating S. spallanzanii may struggle with future high PCO2 conditions. -- Keywords : Individual approach ; PCO2 ; Climate change ; Homeostatic capacity ; Annelid ; Mediterranean Sea

Metabolic responses to high pCO2 conditions at a CO2 vent site in juveniles of a marine isopod species assemblage

We are starting to understand the relationship between metabolic rate responses and species' ability to respond to exposure to high pCO2. However, most of our knowledge has come from investigations of single species. The examination of metabolic responses of closely related species with differing distributions around natural elevated CO2 areas may be useful to inform our understanding of their adaptive significance. Furthermore, little is known about the physiological responses of marine invertebrate juveniles to high pCO2, despite the fact they are known to be sensitive to other stressors, often acting as bottlenecks for future species success. We conducted an in situ transplant experiment using juveniles of isopods found living inside and around a high pCO2 vent (Ischia, Italy): the CO2 'tolerant' Dynamene bifida and 'sensitive' Cymodoce truncata and Dynamene torelliae. This allowed us to test for any generality of the hypothesis that pCO2 sensitive marine invertebrates may be those that experience trade-offs between energy metabolism and cellular homoeostasis under high pCO2 conditions. Both sensitive species were able to maintain their energy metabolism under high pCO2 conditions, but in C. truncata this may occur at the expense of [carbonic anhydrase], confirming our hypothesis. By comparison, the tolerant D. bifida appeared metabolically well adapted to high pCO2, being able to upregulate ATP production without recourse to anaerobiosis. These isopods are important keystone species; however, given they differ in their metabolic responses to future pCO2, shifts in the structure of the marine ecosystems they inhabit may be expected under future ocean acidification conditions

Studio delle componenti biotiche ed abiotiche di un sistema lagunare Brasiliano: popolamenti bentonici ed analisi degli isotopi stabili.

Dalla seconda metà degli anni settanta gli isotopi stabili sono stati ampiamente utilizzati per rispondere a varie questioni in relazione al ciclo del carbonio in ambienti costieri, sia nell’identificazione delle fonti di materia organica, sia nel destino di questi elementi nelle catene a-limentari dove i popolamenti bentonici rivestono un ruolo chiave (Eldridge et al., 2005). Gli obiettivi di questo lavoro, realizzato attraverso campionamenti in due compartimenti del sistema lagunare di Maricá, nello stato di Rio de Janeiro sono stati: - la caratterizzazione dei popolamenti bentonici e dei parametri abiotici - l’individuazione del ruolo delle fonti di materia organica per i consumatori attraverso l’ analisi degli isotopi stabili di carbonio ed azoto (13C, 15N) nella vegetazione, nel detrito vegetale, nel macrozoobenthos, nell’ittiofauna e nella materia organica presente nel sedimento. A circa 60 km da Rio de Janeiro, il sistema lagunare di Maricá non è mai stato studiato a fondo. Appartiene ad uno dei più vasti complessi lagunari dell’intero stato di Rio de Janeiro, denominato Maricá – Guarapina, costituito da quattro compartimenti distinti e comunicanti tra loro: Guarapina, Barra, Padre e Maricá, che si estendono lungo la costa. Nel margine della laguna ancora non antro-pizzato vi sono ampi banchi di fanerogame marine del genere Typha, che contribuiscono come fonte di materia organica vegetale. E’ stato realizzato un disegno sperimentale per il quale, del sistema lagunare, sono state scelte a priori le due lagune “marginali”, situate ognuna ad una estremità del complesso lagunare: Maricá e Guarapina All’interno di ogni laguna sono stati individuati due siti di campionamento. Tali siti sono stati individuati in base alla presenza/assenza di vegetazione lungo i margini, come potenziale fonte di alimentazione per il macrozoobenthos. Per quanto riguarda la caratterizzazione dei popolamenti bentonici, in ogni sito sono state effettuate tre repliche o cinque, nel caso dei campioni di macrofauna. Sono stati raccolti ed analizzati campioni di macrofauna con l’ausilio di un carotatore in PVC (15 cm di diametro e 30 cm di altezza), setacciati in campo con maglie da 1,0 mm e 0,5 mm. In ogni sito, il sedimento è stato campionato per le analisi granulometriche e la materia organica totale. I campioni sono stati congelati a -20°C. E’ stato utilizzato un corer di 10 cm di diametro per le analisi della clorofilla-a e dei feopigmenti; il primo centimetro del corer è stato isolato ed il materiale conservato in contenitori in plastica neri ed immediatamente congelato. Nel sedimento sono state effettuate misurazioni di ossigeno disciolto, temperatura, salinità, Eh. Per quanto riguarda l’individuazione del ruolo delle fonti di materia organica per i consumatori in ogni laguna sono stati identificati e raccolti i principali elementi fonte di materia organica, come la fanerogama Typha, così come organismi rappresentativi del benthos. Tali campioni sono stati lavati con acqua distillata per la rimozione dei residui, successivamente congelati e su questi è stata con-dotta l’analisi degli isotopi stabili. Inoltre, con la collaborazione di pescatori locali, sono stati raccolti esemplari di ittiofauna, congelati, identificati e da essi sono stati isolati dei campioni di tessuto, da processare per le analisi degli isotopi stabili. Tali analisi consentono di valutare l’arricchimento di 13C e 15N nei vari gruppi di organismi e met-terlo in relazione alle potenziali fonti di materia organica per i consumatori

Spatio-temporal variability of polychaete colonization at volcanic CO2 vents indicates high tolerance to ocean acidification

Ocean acidification is predicted to have negative effects on marine biota, resulting in the loss of biodiversity and changes in marine ecosystem structure and function. However, some species and life stages may be capable of thriving in low pH conditions, either due to their natural ability to tolerate stressful low pH-high pCO(2) conditions and/or alteration of species interactions caused by changes in pH profiles, or due to evolutionary trade-offs. A better understanding of which species may be capable of tolerating ocean acidification can guide future research into the mechanisms for physiological and ecological resilience to future carbon dioxide (CO2) conditions. We investigated the colonization of selected polychaete species along a pH gradient originating from shallow, coastal volcanic CO2 vents (Ischia, Italy). Colonization was quantified by exposing artificial invertebrate collectors attached to the substratum for 30 days during different periods of the year (late spring, fall and late winter). Three species, Amphiglena mediterranea, Platynereis dumerilii and Syllis prolifera, were present and abundant along the gradient throughout the year. All three species were significantly more abundant in the most acidified areas, confirming their high tolerance and capacity to cope with very low pH. Abundances of all three species were compared to data previously collected via collectors suspended in the water column. More individuals were found in the collectors attached to the substratum, suggesting that abundances may have previously been underestimated. This is likely due to the close proximity of these collectors with the natural rocky substratum. All three species exhibited similar temporal variability, consistent with their life cycle and reproductive biology. Our results demonstrate high tolerance of the species for low and variable pH and corroborate their use as robust models to explore the capacity to cope with low pH-high pCO(2) conditions, both in the natural vent systems and in the laboratory

Proteomic profiles of Platynereis spp. collected from inside and outside the CO2 vent (Ischia, Italy) and used in a reciprocal transplant experiment in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) (stations A1-A3) or outside (40°43'33.33"N, 13°57'36.38"E and 40°44′48″N, 13°56′39″E) (stations C1-C3) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the proteome of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. This experiment was conducted between 04/09/2013 and 16/09/2013. The experiment was staggered during this time so all worms could be processed. After five days exposure to either low or high CO2 conditions worms were snap frozen in liquid nitrogen and shipped to the University of Hong Kong for proteomic analysis which was finalised on 02/08/2015. Proteomic profiles of worms were characterised using a liquid chromatography-mass spectrometry/mass spectrometry triple time of flight (LC-MS/ MS Triple TOF) approach

Metabolomic profiles of Platynereis spp. collected from inside and outside the CO2 vent (Ischia, Italy) and used in a reciprocal transplant experiment in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) or outside (40°43'33.33N, 13°57'36.38E and 40°44′48″N, 13°56′39″E) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the metabolome (metabolome, and lipidome) of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. This experiment was conducted between 04/09/2013 and 16/09/2013. The experiment was staggered during this time so all worms could be processed. After five days exposure to either low or high CO2 conditions worms were snap frozen in liquid nitrogen and shipped to the University of Birmingham for metabolomic analysis which was finalised on 21/01/2016. Metabolomic profiles of worms were characterised using a mass spectrometry approach. A standard mass spectrometry based metabolomics workflow was used to analyse both the polar and lipid extracts from the samples (Kirwan et al. 2014). Raw mass spectral data were processed using the SIM-stitching algorithm, using an in-house Matlab script. The data matrices were normalized using the PQN algorithm. Missing values were imputed using the KNN algorithm. The resulting data matrix was analysed using univariate statistics, described below. The same matrix was transformed using the generalised logarithm to stabilise the technical variance across the measured peaks prior to analysis using multivariate statistics. Signals were putatively annotated with empirical formulae calculated by the MIPack software (Weber et al. 2010), searching the KEGG (Kanehisa et al. 2012) and LipidMaps (Fahy et al. 2007) databases, and confirmed by performing calculations based on the original spectra in Xcalibur 2.0.7 (Thermo Fisher Scientific)

Environmental conditions inside and outside the CO2 vent (Ischia, Italy) before and during a reciprocal transplant experiment with Platynereis spp. in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) (stations A1-A3) or outside (40°43'33.33"N, 13°57'36.38"E and 40°44′48″N, 13°56′39″E) (stations C1-C3) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment between 04/09/2013 and 16/09/2013. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the proteome and metabolome (metabolome, and lipidome) of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. Before and during the transplant experiment water samples were taken to characterise the physio-chemical parameters of sea water used when exposing the worms to: (i) low pCO2 conditions (‘control’ stations C1, C2 and C3) and (ii) high pCO2 conditions (‘acidified’ stations A1, A2, A3). Salinity, temperature, pH NBS (Mettler-Toledo pH meter, Beaumont Leys, UK), total alkalinity (TA) (AS-ALK2, Apollo SciTech, Bogart, USA), dissolved inorganic carbon (DIC), carbon dioxide partial pressure (pCO2), bicarbonate and carbonate ion concentration ([HCO3–] and [CO32–), calcite and aragonite saturation state (Ωcal and Ωara) are provided