Open Marine Ecosystems Research Articles

Rapid reservoir fisheries appraisal (r-RAPFISH): Indicator based framework for sustainable fish production in Indian reservoirs

Indian fisheries is a sunrise sector with untapped potential and opportunities. The reservoir fisheries, labelled a sleeping giant due to its locked-up potential, promises to be a game changer while insufficient scientific evidence on its health status impedes development. This study adapts the well-known Rapid Fisheries Appraisal (RAPFISH) technique, a multi-disciplinary framework developed for macro-assessment of marine fisheries, to the micro-level reservoir fishery in a data limiting developing country context. Fundamental differences namely the small bounded reservoir ecosystem versus the large open marine ecosystem, (over)exploited marine fisheries versus underdeveloped reservoir fisheries, homogeneous marine fishers versus heterogeneous reservoir fishers, and the invisible low-profile reservoir fisheries necessitated this adaptation. A rigorous multi-stage procedure with extensive literature review, stakeholders' feedback, statistical validation (Weighted Sum Model and Analytic Hierarchy Process-Like Procedure) followed by field testing in southern India formed the bedrock of this methodological exercise. From a universe of 93 indicators under 6 evaluation fields, the study yielded a reservoir specific RAPFISH with 25 indicators grouped under 5 evaluation fields: ecological, economic, technological, social and governance. The RAPFISH ordination values for Veedur and Pechiparai reservoirs ranged from 35.13% (economic field - ‘poor’ status) to 68.98% (ecology field - ‘good’ status), demonstrating the modified technique's ability to differentiate and demonstrate variability in fisheries studied. The study offers r-RAPFISH as a customised tool for researchers in Asia and Africa to assess the health of reservoir fisheries and plan interventions to help achieve Sustainable Development Goals (SDG) of no poverty (SDG - 1), no hunger (SDG - 2) and life below water (SDG - 14) through sustainable inland fisheries.

The Late Ordovician Tafilalt Biota, Anti-Atlas, Morocco: a high-latitude perspective on the GOBE

Abstract The extensive, predominantly siliciclastic deposits of the Upper Ordovician of the Tafilalt have long been the subject of scientific investigation. In the past 25 years, intensified collecting for commercial purposes has resulted in the discovery of several exceptionally-preserved faunas (Konservat-Lagerstätten) in the Tafilalt region, preserving a range of non-biomineralized and soft-bodied organisms. The preservation of these fossils in the coarse clastic sediments of the Tafilalt is surprising, and in the case of soft-bodied organisms, remarkably similar to the preservational mode of typical Ediacaran biotas. These relatively recent discoveries have increased the scientific significance of the Tafilalt Biota, providing an unparalleled insight into the composition and temporal evolution of the shallow, open-marine ecosystems and their denizens during the later stages of the Great Ordovician Biodiversification Event. At least nine different phyla, in addition to several soft-bodied problematica are represented in the Tafilalt. While the highly diverse and remarkably well-preserved echinoderm and euarthropod faunas are most emblematic for the Tafilalt Biota, further studies have revealed a relatively high diversity of molluscs and brachiopods. Among soft-bodied fossils, the problematic paropsonemid eldonids are iconic for the Tafilalt and stand out both through their abundance, and their wide temporal and geographical range throughout the area.

Modified VG-CL Detection System for Baseline Assessment of Dimethylsulphide and Dimethylsulphoniopropionate in Tropical Atlantic Seawater

Several studies have been carried out to measure the concentrations of dimethylsulphide (DMS) and dimethylsulphoniopropionate (DMSP) in coastal and open marine ecosystems. The present study attempted the fabrication of a cost-effective, highly sensitive and portable detection system based on vapour generation and chemiluminescence for a pilot assessment and determination of DMS and DMSP concentrations in tropical Atlantic seawater samples. The Sultan Beach and Badagry parts of the Atlantic Ocean were chosen as designated locations for this study. Vapour generation chemiluminescence (VG-CL) detection system is a device that can measure the concentration (nM) of DMS and DMSP by allowing DMS vapour which in turn reacts with ozone to produce chemiluminescence which can be detected by a photomultiplier (PMT). The mean concentrations of DMS and DMSP in the surface seawater at the sampling location were 5.80±0.71 to 19.40±0.57 nM and 11.00±0.42 to 34.70±1.13 nM, respectively. The average minimum and maximum concentrations of DMS and DMSP across the location were between 0 and 40.91 nM, respectively. This study serves as a baseline measurement of DMS concentrations in the tropical Atlantic Ocean (Lagos).

Firm evidence for a post-extinction ichnofauna: earliest CarboniferousCruziana reticulataassemblage from the Anti-Atlas of Morocco

Cruziana reticulata is an arthropod-related ichnospecies that is characterized by a conspicuous net-like scratch pattern whose initial formation and later preservation require the presence of consolidated substrates in shallow marine fine-grained bottoms. There are two scenarios in which epifaunal to shallow infaunal benthic organisms may access firm siliciclastic substrates: first, by exposure of the compacted bottom after erosion of the upper, water-saturated and usually soft portion of sediment column; and, second, by primary fast substrate stabilization in the absence of biogenic sediment mixing. Whereas the first mode occurs throughout the Phanerozoic, the latter is only prevalent in marine bottoms during the Early Palaeozoic mainly as a consequence of poorly developed infaunal bioturbation. However, by eradicating burrowing organisms, mass extinctions are known (i.e. the end-Permian extinction) to ‘reset’ intensity of ecospace utilization, which entails the return to this anachronistic style of trace fossil preservation in younger times. An earliest Carboniferous ichno-assemblage dominated by Cruziana reticulata from Morocco attests the spread of firm substrates in the aftermath of the Hangenberg Event – a major extinction at the end of the Devonian period. Since evidence for erosion is lacking in accompanying sedimentary rocks and the ichno-assemblage shows characteristics of opportunistic exploitation of the nutritious muddy seabed, we favour the interpretation of this assemblage to represent a post-extinction ichnofauna. It shows that other taxonomically less severe mass extinctions may also exhibit transient but severe ecological effects in open marine ecosystems such as the collapse of vital sediment mixing. Such post-extinction effects may distort the perception of the stratigraphical record as a firmground ichno-assemblage often taken as evidence for submarine erosion and are crucial in highlighting sequence boundaries. We, thus, encourage appreciating macroevolutionary framework of respective ichnofaunas.

The end of the Great Khersonian Drying of Eurasia: Magnetostratigraphic dating of the Maeotian transgression in the Eastern Paratethys

AbstractCentral Eurasia underwent significant palaeoclimatic and palaeogeographic transformations during the middle to late Miocene. The open marine ecosystems of the Langhian and Serravallian seas progressively collapsed and were replaced in the Tortonian by large endorheic lakes. These lakes experienced major fluctuations in water level, directly reflecting the palaeoclimatic conditions of the region. An extreme lowstand of the Eastern Paratethys lake (−300 m) during the regional Khersonian stage reveals a period of intensely dry conditions in Central Eurasia causing a fragmentation of the Paratethys region. This period of “Great Drying” ended by a climate change towards more humid conditions at the base of the Maeotian stage, resulting in a large transgressive event that reconnected most of the Paratethyan basins. The absence of a robust time frame for the Khersonian–Maeotian interval hampers a direct correlation with the global records and complicates a thorough understanding of the underlying mechanisms. Here we present a new chronostratigraphic framework for the Khersonian and Maeotian deposits of the Dacian Basin of Romania, based on integrated magneto‐biostratigraphic studies on long and continuous sedimentary successions. We show the dry climate conditions in the Khersonian start at 8.6–8.4 Ma. The Khersonian/Maeotian transition is dated at 7.65–7.5 Ma, several million years younger than previous estimates. The Maeotian transgression occurs later (7.5–7.4 Ma) in more marginal and shallower basins, in agreement with the time transgressive character of the flooding. In addition, we date a sudden water level drop of the Eastern Paratethys lake, the Intra‐Maeotian Event (IME), at 6.9 Ma, and hypothesize that this corresponds to a reconnection phase with the Aegean basin of the Mediterranean. Finally, we discuss the potential mechanisms explaining the particularities of the Maeotian transgression and conclude that the low salinity and the seemingly “marine influxes” most likely correspond to episodes of intrabasinal mixing in a gradual and pulsating transgressive setting.

Innovative Approach to Sustainable Marine Invertebrate Chemistry and a Scale-Up Technology for Open Marine Ecosystems.

Isolation of marine compounds from living invertebrates represents a major challenge for sustainable and environmentally friendly exploitation of marine bio-resources. To develop innovative technology to trap invertebrate compounds in the open sea, the proof of concept of a system combining external continuous circulation of water with XAD-amberlite solid-phase extraction was validated in an aquarium. In this work, we reported the elicitation of guanidine alkaloid production of Crambe crambe in the presence of Anemonia sulcata, both collected from the Mediterranean Sea. Besides the previously reported crambescidin 359 (1), and crambescidin acid (2), three new compounds were isolated; one carboxylated analog of 1 named crambescidin 401 (3), and two analogs of crambescin B, crambescin B 281 (4) and crambescin B 253 (5). Based on these results, a technology named Somartex® for “Self Operating MARine Trapping Extractor” was patented and built to transfer the concept from closed aquarium systems to open marine ecosystems.

Connectivity and population repatriation: limitations of climate and input into the larval pool

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 495:175-183 (2014) - DOI: https://doi.org/10.3354/meps10590 Connectivity and population repatriation: limitations of climate and input into the larval pool Rhiannon L. Rognstad*, David S. Wethey, Thomas J. Hilbish Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, South Carolina 29208, USA *Corresponding author: rlrognstad@gmail.com ABSTRACT: We used climate-induced variation in fecundity of the barnacle Semibalanus balanoides to test the hypothesis that variation in adult input to the larval pool is a driver of connectivity among adult populations of coastal marine invertebrates. We predicted that cold winters will lead to high reproductive output and high recruitment by S. balanoides, while warm winters will result in low reproductive output and low recruitment. Following the cold winter of 2009 to 2010, larval recruitment was exceptionally high (>6 cm2) in Southwest England, resulting in a range expansion of over 100 km. The following winter was also cold, and recruitment was again high. The winter of 2011 to 2012 was warm, and recruitment was low (~1cm-2) throughout Southwest England. These data indicate that recruitment and population connectivity are strongly linked to adult input to the larval pool. We analyzed winter temperature variation over the past 3 decades and found that warm winter temperatures over the 13 yr prior to this study likely led to frequent reproductive failure and the decline of S. balanoides in Southwest England. Continued warming in this region is likely to permanently exclude S. balanoides from this portion of its geographic range. This study illustrates an important role of adult input into the larval pool in controlling population connectivity in open marine ecosystems and also implicates climate variation in determining the range limit of a significant component of coastal ecosystems in Europe. KEY WORDS: Connectivity · Semibalanus · Climate change · Recruitment · Biogeography Full text in pdf format PreviousNextCite this article as: Rognstad RL, Wethey DS, Hilbish TJ (2014) Connectivity and population repatriation: limitations of climate and input into the larval pool. Mar Ecol Prog Ser 495:175-183. https://doi.org/10.3354/meps10590 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 495. Online publication date: January 09, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Enhanced bioaccumulation of mercury in deep-sea fauna from the Bay of Biscay (north-east Atlantic) in relation to trophic positions identified by analysis of carbon and nitrogen stable isotopes

The Bay of Biscay (north-east Atlantic) is an open marine ecosystem of particular concern in current European environmental policies. Indeed, it supports both a high biological diversity and numerous anthropogenic activities such as important fisheries. For the first time, stable isotope analyses (SIA) of carbon and nitrogen and analysis of total mercury (T-Hg) concentrations in the muscle (edible flesh) were performed on adult stages of a wide range of species (i.e., 120 species) from various taxa and various habitats of this ecosystem. Concentrations of this non-essential metal, toxic to all living organisms, ranged from 39 to 5074ngg−1 dry weight. Calculations of species' trophic positions (TPs) through SIA revealed a limited effect of TP in explaining Hg bioaccumulation by high trophic level consumers in particular. On the contrary, our results suggest an important role of habitat and/or feeding zone, which strongly influence muscle Hg bioaccumulation. Deep-sea fish species effectively presented the highest Hg concentrations. Possible interactions between biological factors (e.g., age of deep-sea organisms) and bioavailability of the metal in the deep-sea environment are discussed to explain such enhanced bioaccumulation of Hg by deep-sea fauna in the Bay of Biscay. This study also highlights a potential risk for human health when deep-sea fish are consumed frequently.

Seasonal dynamics of trophic relationships among co-occurring suspension-feeders in two shellfish culture dominated ecosystems

The temporal dynamics of carbon and nitrogen isotope values of co-occurring suspension-feeders in two shellfish culture areas (Normandy, France) were investigated over two years to evaluate the inter-specific trophic partitioning and relative contributions of organic matter sources to benthic suspension-feeders' diet. Oysters ( Crassostrea gigas), mussels ( Mytilus edulis), cockles ( Cerastoderma edule), slipper limpets ( Crepidula fornicata), and sand-mason worms ( Lanice conchilega) were sampled in an estuarine environment (Baie des Veys, east Cotentin, Normandy), while oysters, mussels, slipper limpets, and honeycomb worms ( Sabellaria alveolata) were sampled in an open-marine environment (Lingreville-sur-mer, west Cotentin, Normandy). Whatever the sampling period, the bivalves, C. gigas and M. edulis, exhibited the lowest values of δ 13C and δ 15N compared with the other species. Feeding relationships among suspension-feeders in both C. gigas culture areas exhibited temporal variations due to the marine/estuarine influence and seasonal changes in food supply. In the open-marine ecosystem, the contribution of phytoplankton remained the most important for all species except S. alveolata, while in the estuarine ecosystem, microphytobenthos and/or macroalgae detritus contributed a larger extent to the organisms' diets. During phytoplankton bloom periods (e.g. May and July) suspension-feeders, except for S. alveolata, relied strongly on phytoplankton; however, the majority of suspension-feeders exhibited different opportunistic behaviour in winter when phytoplankton biomass might be a limiting factor. We hypothesized that differences in particle capture and selection by the suspension-feeders influenced their isotopic values. Feeding ecology of suspension-feeders partly explained why competition was limited and why ecosystems can often support unexpectedly large numbers of suspension-feeders. We also showed that understanding ecosystem characteristics of the organic matter sources is of primary importance to determine the extent to which members of the suspension-feeding guild potentially compete for food.

Rapid speciation in a newly opened postglacial marine environment, the Baltic Sea.

BackgroundTheory predicts that speciation can be quite rapid. Previous examples comprise a wide range of organisms such as sockeye salmon, polyploid hybrid plants, fruit flies and cichlid fishes. However, few studies have shown natural examples of rapid evolution giving rise to new species in marine environments.ResultsUsing microsatellite markers, we show the evolution of a new species of brown macroalga (Fucus radicans) in the Baltic Sea in the last 400 years, well after the formation of this brackish water body ~8–10 thousand years ago. Sympatric individuals of F. radicans and F. vesiculosus (bladder wrack) show significant reproductive isolation. Fucus radicans, which is endemic to the Baltic, is most closely related to Baltic Sea F. vesiculosus among north Atlantic populations, supporting the hypothesis of a recent divergence. Fucus radicans exhibits considerable clonal reproduction, probably induced by the extreme conditions of the Baltic. This reproductive mode is likely to have facilitated the rapid foundation of the new taxon.ConclusionThis study represents an unparalleled example of rapid speciation in a species-poor open marine ecosystem and highlights the importance of increasing our understanding on the role of these habitats in species formation. This observation also challenges presumptions that rapid speciation takes place only in hybrid plants or in relatively confined geographical places such as postglacial or crater lakes, oceanic islands or rivers.

Multi-level trophic cascades in a heavily exploited open marine ecosystem

Anthropogenic disturbances intertwined with climatic changes can have a large impact on the upper trophic levels of marine ecosystems, which may cascade down the food web. So far it has been difficult to demonstrate multi-level trophic cascades in pelagic marine environments. Using field data collected during a 33-year period, we show for the first time a four-level community-wide trophic cascade in the open Baltic Sea. The dramatic reduction of the cod (Gadus morhua) population directly affected its main prey, the zooplanktivorous sprat (Sprattus sprattus), and indirectly the summer biomass of zooplankton and phytoplankton (top-down processes). Bottom-up processes and climate-hydrological forces had a weaker influence on sprat and zooplankton, whereas phytoplankton variation was explained solely by top-down mechanisms. Our results suggest that in order to dampen the occasionally harmful algal blooms of the Baltic, effort should be addressed not only to control anthropogenic nutrient inputs but also to preserve structure and functioning of higher trophic levels.

DEPOSITIONAL DYNAMICS AND THE RECORD OF ECOSYSTEM STABILITY: EARLY EOCENE FAUNAL GRADIENTS IN THE PYRENEAN FORELAND, SPAIN

We studied mollusk-dominated multispecies assemblies from the south Pyrenean foreland in Spain by using relative abundance data in a framework of high-frequency depositional sequences for an interval spanning 2 myr across the early Eocene climatic optimum. The sequences are part of the Figols (middle Ypresian) and Castigaleu (upper Ypresian) allogroups and together document environmental changes influenced by tectonics at the lower frequency and driven by sea level and climate at the high-frequency temporal scale. We applied ordination through multidimensional scaling and other techniques to explore the structure of the data set. Six Figols and eight Castigaleu communities, linked along onshore-offshore gradients, were interpreted on uniformitarian grounds. Paleoenvironments ranged from mangrove forest to tidal flat, tidal creek, estuary, delta front, shoreface, carbonate ramp, and inner shelf. Some habitats were represented throughout the interval, allowing examination of the effect on coastal ecosystems of environmental disturbances tied to sea-level lowstands, as deduced from the sequence stratigraphic analysis. These disturbances presumably amounted to extirpation by river floods, burial, increased turbidity, high river-derived nutrient input, and decreased ecospace availability. The major effect on the mangrove-estuary-delta gradient was coincident with the unconformity separating the two allogroups. Mangrove communities suffered a change in rank of dominating species and a turnover of rare species. Subtidal estuarine and delta communities were affected in their relative abundances, but we observed no change in rank or turnover. We suggest that the different niche breadth of organisms leads to different responses to perturbation of several scales. Many intertidal cerithioidean gastropods went extinct, whereas subtidal turritelline gastropods were unchanged, during the major environmental variation. Mangrove gastropods experienced increased originations in the upper Ypresian. The carbonate ramp heterotrophs did not change across the Figols-Castigaleu perturbation, although throughout the early Eocene the phototroph guild within the same ecosystem was undergoing frequent turnover events. All studied associations showed significant changes in the relative abundances of constituent species across unconformities of minor entity, proving that soft-bottom marine communities conform to an open-membership model of ecosystem recruitment, as suggested by studies of past open marine ecosystems. Persistence to a degree is suggested by mangrove communities, indicating a slightly more limited membership in low-nutrient estuarine habitats, a response more similar to that of coral reef tropical ecosystems. This study confirms the idea that different species and communities may experience opposite effects from the same events and shows that faunal distributions in estuarine and deltaic systems reflect more than just bathymetric change. High onshore origination also conforms to the theory of onshore-offshore faunal change.

Atmospheric Deposition and Marine Sedimentation Fluxes of Polycyclic Aromatic Hydrocarbons in the Eastern Mediterranean Basin

Atmospheric input was studied and found to be the major source of PAHs in the eastern Mediterranean open marine ecosystem. Dry and wet atmospheric deposition, air-sea exchange, and sediment trap fluxes of polycyclic aromatic hydrocarbons (PAHs) in the eastern Mediterranean basin were estimated from November 2000 to July 2002. Seven dry and four wet deposition samples were analyzed in total and PAH concentrations were determined. Airsea exchange fluxes based on air-water concentration gradientwere drawn from five air and water samples collected concurrently from a coastal area in the eastern Mediterranean. Total annual average deposition fluxes of dry, wet, and air-sea exchange sigma35PAHs were 58.0, 165.7, and -706.4 microg m(-2) y(-1), respectively. Only 1.1 and 0.7% of the total atmospheric deposition flux of PAHs was measured in the sediment traps at 280 and 1440 m depth, respectively.

BIBLE A whole‐air sampling as a window on Asian biogeochemistry

Asian trace gas and aerosol emissions into carbon, nitrogen, and other elemental cycles will figure prominently in near term Earth system evolution. Atmospheric hydrocarbon measurements resolve numerous chemical species and can be used to investigate sourcing for key geocarriers. A recent aircraft study of biomass burning and lightning (BIBLE A) explored the East Asian atmosphere and was unique in centering on the Indonesian archipelago. Samples of volatile organics taken over/between the islands of Japan, Saipan, Java, and Borneo are here examined as a guide to whole‐air‐based studies of future Asian biogeochemistry. The midlatitude onshore/offshore pulse and tropical convection strongly influence concentration distributions. As species of increasing molecular weight are considered, rural, combustion, and industrial source regimes emerge. Methane‐rich inputs such as waste treatment and rice cultivation are evidenced in the geostrophic outflow. The Indonesian atmosphere is rich in biomass burning markers and also those of vehicular activity. Complexity of air chemistry in the archipelago is a direct reflection of diverse topography, land use, and local economies in a rapidly developing nation. Conspicuous in its absence is the fingerprint for liquefied petroleum gas leakage, but it can be expected to appear as demand for clean fossil fuels rises along with per capita incomes. Combustion tracers indicate high nitrogen mobilization rates, linking regional terrestrial geocycles with open marine ecosystems. Sea to air fluxes are superimposed on continental and marine backgrounds for the methyl halides. However, ocean hot spots are not coordinated and suggest an intricate subsurface kinetics. Levels of long‐lived anthropogenic halocarbons attest to the success of international environmental treaties while reactive chlorine containing species track industrial air masses. The dozens of hydrocarbons resolvable by gas chromatographic methods will enable monitoring of upcoming Asian modernization. Crucial uncertainties are underscored. Signatures for Asian combustion processes and megacities have been obtained only indirectly or at a distance. Detailed fingerprinting must be combined with regular aircraft and ground station measurements to maximize utility of the database.