Nitrogen inputs to seventy-four southern New England estuaries: Application of a watershed nitrogen loading model

Excess nitrogen inputs to estuaries have been linked to deteriorating water quality and habitat conditions which in turn have direct and indirect impacts on aquatic organisms. This paper describes the application of a previously verified watershed loading model to estimate total nitrogen loading rates and relative source contributions to 74 small-medium sized embayment-type estuaries in southern New England. The study estuaries exhibited a gradient in nitrogen inputs of a factor of over 7000. On an areal basis, the range represented a gradient of approximately a factor of 140. Therefore, all other factors being equal, the study design is sufficient to evaluate ecological effects conceptually tied to excess nitrogen along a nitrogen gradient. In addition to providing total loading inputs rates to the study estuaries, the model provides an estimate of the relative contribution of the nitrogen sources from each watershed to each associated estuary. Cumulative results of this analysis reveal the following source ranking (means): direct atmospheric deposition (37%), ≈wastewater (36%), >indirect atmospheric deposition (16%) > fertilizer (12%). However, for any particular estuary the relative magnitudes of these source types vary dramatically. Together with scientific evidence on symptoms of eutrophication, the results of this paper can be used to develop empirical pressure-state models to determine critical nitrogen loading limits for the protection of estuarine water quality.     

Miocene facies associations and sedimentary evolution of the Southern Transylvanian Basin (Romania): Implications for hydrocarbon exploration

The Transylvanian Basin is a mature hydrocarbon province of Romania characterized by two petroleum systems: Mesozoic (thermogenic) and Miocene (biogenic). An extensive outcrop-based sedimentological and micropaleontological study correlated to seismic and well data discusses the elements of the Miocene petroleum system. The facies associations are indicative of alluvial, fandelta, shallow- and deep-marine settings. These are grouped into four different depositional systems (evaporite, mud-carbonate, sand-mud and sand-gravel). Their evolution in time and space shows large differences between various parts of the basin that have important consequences for exploration.     

Control of Aptian palaeobathymetry on turbidite distribution in the Buchan Graben,Outer Moray Firth,Central North Sea

It is widely recognised that palaeobathymetry is a key control on the distribution of turbidite deposits. Thus, the utilisation of palaeobathymetric surfaces as an input for numerical turbidity current modelling offers a potentially powerful method to predict the distribution of deep marine sands in ancient (subsurface or outcrop) successions. Such an approach has been tested on an Aptian turbidite deposit from the Buchan Graben, UK Central North Sea, where modelled sand distributions could be quality controlled against available well data.     

Structurally controlled hydrothermal dolomites in Albian carbonates of the Asón valley,Basque Cantabrian Basin,Northern Spain

Shallow marine carbonate sedimentation dominated during the Albian in the western part of the Basque Cantabrian Basin in Northern Spain, forming the large Ramales Platform. This platform originated on a less subsiding tectonic block facing deeper and more subsiding areas to the south and east, which were created by tectonic activity in the Basin. Fracture-related hydrothermal dolomites hosted in these Albian carbonates are well exposed in the Asón valley area. Mapping in the studied area revealed several dolomite bodies related to main faults that cut the stratification almost at right angles. The bodies show a vertical development along fault-strike up to 900 m thick from which kilometre-scale branches expand following the stratification. Dolomitization is pervasive and independent of the limestone facies. Main dolomite facies are fine replacive, sucrosic and saddle. Petrography, C, O and Sr isotopes and fluid-inclusion analysis support a polyphase hydrothermal dolomitization at fluid temperatures between 75 °C and 240 °C and highly variable salinity of up to 22 wt.% NaCl. Fine dolomite replaced limestone first and then, sucrosic and saddle dolomites replaced part of the first dolomite and cemented newly created fracture porosity together with different calcite cements. Zebra dolomites and hydroclastic breccias are products of this later stage. Burial analysis of the host rock supports maximum burial temperatures of 80 °C and intense tectonic activity from the Albian to Turonian with a latest Albian peak subsidence. Albian stretching of the crust and subsequent ascent of the isotherms in the area is suggested to have produced sufficient heat to the dolomitizing fluids. The structural analysis indicates a strong transtensional tectonic activity in the studied area during Albian to Turonian time with the creation of an overstep between W–E trending and N–S trending faults. Fluids moved from subsiding areas to fractured uplifted parts of the Ramales Platform, enhanced by diapiric activity.     

Permafrost as a factor of the dynamics of the coastal zone of the Russian East Arctic Seas

Some regularities that are generally accepted in the theory about the development of sea coasts as applied to the East Arctic coast of Russia do not conform to reality. To find out the reasons for these contradictions, the connection between the coastal processes and the perennially frozen sediment of the underwater coastal slope in the Laptev Sea and the East Siberian Sea was studied. The frozen state of the deposits of the coastal zone exerts a substantial influence on the coastal dynamics and determines several features of the thermoabrasion development. In particular, the subaqual permafrost does not allow the forming of a storm profile with dynamic balance. This fact causes the more effective action of the sea on the coastal cliffs and the more active recession of the frozen coasts as compared with their counterparts outside the cryolitozone.     

Managing overcapacity in small-scale fisheries in Southeast Asia

It is now almost universally accepted that most of the nearshore fisheries in Southeast Asia are overfished. It is also accepted that overcapacity is one of the leading causes of this overfishing. The problem of addressing overcapacity in small-scale fisheries in Southeast Asia is much more complex than that of reducing overcapacity in industrial fleets. In order to manage capacity, managers need to measure and understand how much capacity currently exists in the fishery and what is the desirable level of capacity that best meets the set of management objectives. The only feasible solution to overcapacity may be based on a coordinated and integrated approach involving a mixed strategy of resource management, resource restoration and conservation, livelihoods and economic and community development, and restructured governance arrangements. The reduction of overcapacity implies an increased focus on people-related solutions and on communities.     

Modelling mussel growth in ecosystems with low suspended matter loads using a Dynamic Energy Budget approach

The environmental and the economic importance of shellfish stimulated a great deal of studies on their physiology over the last decades, with many attempts to model their growth. The first models developed to simulate bivalve growth were predominantly based on the Scope For Growth (SFG) paradigm. In the last years there has been a shift towards the Dynamic Energy Budget (DEB) paradigm. The general objective of this work is contributing to the evaluation of different approaches to simulate bivalve growth in low seston waters by: (i) implementing a model to simulate mussel growth in low suspended matter ecosystems based on the DEB theory (Kooijman, S.A.L.M., 2000. Dynamic and energy mass budgets in biological systems, Cambridge University Press); (ii) comparing and discussing different approaches to simulate feeding processes, in the light of recently published works both on experimental physiology and physiology modeling; (iii) comparing and discussing results obtained with a model based on EMMY (Scholten and Smaal, 1998). The model implemented allowed to successfully simulate mussel feeding and shell length growth in two different Galician Rias. Obtained results together with literature data suggest that modeling of bivalve feeding should incorporate physiologic feed-backs related with food digestibility. In spite of considerable advances in bivalve modeling a number of issues is yet to be resolved, with emphasis on the way food sources are represented and feeding processes formulated.     

Radiative and Thermal Impacts of Smoke Aerosol Longwave Absorption during Fires in the Moscow Region in Summer 2010

The aerosol longwave radiative forcing of the atmosphere and heating rate of the near-surface aerosol layer are estimated for the extreme smoke conditions in the Moscow region in summer 2010. Thermal radiation fluxes in the atmosphere are determined using the integral transmission function and semiempirical aerosol model developed on the basis of standard aerosol models and measurements at the Zvenigorod Scientific Station, Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The aerosol radiative forcing reached 33 W/m² at the lower atmospheric boundary and ranged between–1.0 and 1.0 W/m² at the upper atmospheric boundary. The heating rate of the 10-m atmospheric layer near surface was up to 0.2 K/h during the maximum smoke conditions on August 7–9. The sensitivity of the aerosol longwave radiative forcing to the changes in the aerosol absorption coefficient and aerosol optical thickness are estimated.     

Impacts of alien ‘ecosystem engineers’ overwhelm interannual and seasonal shifts in rocky-shore community composition on Marcus Island,South Africa

The South African coastline has been invaded by numerous alien species. Rare pre-invasion (1980) and post-invasion datasets (2001 and 2012) exist for Marcus Island, a small land-tied island in Saldanha Bay, South Africa. These snapshot datasets of the island’s intertidal invertebrate community were complemented with monitoring across seasons, from 2014 to 2016. Invertebrate communities were compared among the summers of 1980, 2001, 2012, 2014, 2015 and 2016 to assess interannual differences, while invertebrates and algae were monitored quarter-annually to assess seasonal changes. In addition, the population dynamics of the alien mussel Mytilus galloprovincialis were monitored. Differences in invertebrate communities between consecutive summers were significant but much smaller than changes induced by the arrival of alien species. Invertebrate and seaweed communities differed among years and shore zones but not among seasons, whereas species diversity differed among years, seasons and shore zones, with zones having the strongest influence. The invasion by M. galloprovincialis, and ensuing spatial and temporal variability in its recruitment, emerged as the most important factor influencing community composition, overshadowing interannual and seasonal changes. This work highlights that the impacts of alien species can be distinguished from natural variability by combining long-term monitoring with surveys at finer temporal scales. This is an important step in extending our understanding of the impacts of marine alien species.