A lower trophic ecosystem model including iron effects in the Okhotsk Sea

We applied a three-dimensional ecosystem-physical coupled model including iron the effect to the Okhotsk Sea. In order to clarify the sources of iron, four dissolved iron compartments, based on the sources of supply, were added to Kawamiya et al.'s [1995, An ecological-physical coupled model applied to Station Papa. Journal of Oceanography, 51, 635-664] model (KKYS) to create our ecosystem model (KKYS-Fe). We hypothesized that four processes supply iron to sea water: atmospheric loadings from Northeastern Asia, input from the Amur River, dissolution from sediments and regeneration by zooplankton and bacteria. We simulated one year, from 1 January 2001 to 31 December 2001, using both KKYS-Fe and KKYS. KKYS could not reproduce the surface nitrate distribution after the spring bloom, whereas KKYS-Fe agreed well with observations in the northwestern Pacific because it includes iron limitation of phytoplankton growth. During the spring bloom, the main source of iron at the sea surface is from the atmosphere. The contribution of riverine iron to the total iron utilized for primary production is small in the Okhotsk Sea. Atmospheric deposition, the iron flux from sediment and regeneration of iron in the water column play important roles in maintaining high primary production in the Okhotsk Sea.     

Management of the marine environment: integrating ecosystem services and societal benefits with the DPSIR framework in a systems approach

Ever increasing and diverse use of the marine environment is leading to human-induced changes in marine life, habitats and landscapes, making necessary the development of marine policy that considers all members of the user community and addresses current, multiple, interacting uses. Taking a systems approach incorporating an understanding of The Ecosystem Approach, we integrate the DPSIR framework with ecosystem services and societal benefits, and the focus this gives allows us to create a specific framework for supporting decision making in the marine environment. Based on a linking of these three concepts, we present a set of basic postulates for the management of the marine environment and emphasise that these postulates should hold for marine management to be achieved. We illustrate these concepts using two case studies: the management of marine aggregates extraction in UK waters and the management of marine biodiversity at Flamborough Head, UK.     

Modelling the biogeochemistry of a tidal flat ecosystem with EcoTiM

The ecological tidal model simulates the cycling of carbon, nitrogen, phosphate, and silicate and describes the tidal, diurnal, and annual dynamics of the back barrier area of the island Spiekeroog in the German Bight. The region is characterized by strong tidal currents and extensive tidal flats. It is strongly influenced by the conditions in the southern part of the German Bight. This model study investigates the dependence of the model behavior on the boundary conditions and the forcing. The effect of short- and long-term sea level rise on nutrient and plankton dynamics is analyzed. As the model is set up as semi-Lagrangian with only a coarse approximation of the hydrodynamics, the seasonal and intratidal variability in the biogeochemical cycling can only be reproduced qualitatively. By varying the boundary conditions, the intrinsic dynamics of the back barrier area can be separated from boundary condition effects. This study shows that any agreement between model results and field data cannot be expected without correct boundary conditions. The seasonal variability is of major importance, while higher-frequency variability only plays a minor role.     

Organic matter recycling during a mucilage event and its influence on the surrounding environment (Ligurian Sea, NW Mediterranean)

The development of benthic mucilage in the Marine Protected Area of Portofino (Ligurian Sea) during the summer of 2009 was studied to verify the influence of this event on the surrounding environment (seawater and soft-bottom). The calm meteorological and sea conditions at the beginning of the time frame under consideration caused the thermal stratification of the water column. This stratification was one of the driving factors influencing the development of the mucilage, which developed on a large boulder surface above the pycnocline. Mucilage was progressively detached from the boulder surface by hydrodynamism, together with macroalgae, and sank onto the sediment below the thermocline. Increased surface-water movements, caused by meteorological forcing during the study period, influenced the aggregation-disaggregation of mucilage flocks above the thermocline, leading to increased dissolved oxygen concentrations and enhanced production and turnover of the organic matter (OM). Mixing with the adjacent seawater led to the fertilisation of the surrounding environment with potentially labile OM and inorganic phosphorus, which caused increases in the hydrolytic enzymatic activity. Conversely, below the thermocline, the sunken mucilage and algae aggregates supported a heterotrophic consumption system. Dissolved oxygen concentrations were lower than those recorded in the mucilage lying above the thermocline, making more carbohydrates than proteins and labile phosphorus available. Despite the slow oxygenation of this mucilage, it contributed to the food supply for the soft-bottom macrofauna, which showed an increase in density, diversity and biomass during the study. These results suggest that the development and fate of the mucilage, as well as its interactions with the surrounding environment, were principally regulated by physical features. In the oligotrophic coastal area of the Ligurian Sea, certain compartments of the ecosystem were able to promptly respond and take advantage of the mucilage event of the summer of 2009, although the persistence of mucilage on hard substrates is known to cause suffocation and macroalgae biomass depletion. It is proposed that, at least in oligotrophic conditions and as long as mucilage persistence doesn't cause severe oxygen depletion, its appearance might have an enhancing rather than a detrimental effect on the seawater and soft-bottom biogeochemical processes.     

The Baltic Basin Case Study—towards a sustainable Baltic Europe

Four watersheds, each characterized by a major resource use were selected for the study: The Vistula River in Poland—agriculture; the Dalälven River in Sweden—forestry; the Archipelago Sea in Sweden, Finland, Estonia—tourism; and the Lake Peipsi in Estonia/Russia—fisheries/agriculture. The main objective was to examine the reactions of particular ecosystems within the Baltic Sea drainage area, and to assess sustainability conditions on the regional level.The degree of sustainability and impact on the Baltic Sea were investigated through workshops and seminars in the areas. Overviews of environmental and socio-economic conditions were succinctly summarized in commissioned papers. Interventions by and discussions with scholars, sector experts, administrators and stakeholders of the various sites laid the foundation for conceptualizing the interaction of natural and human forces for each case. The project was able to draw quite a number of conclusions, summarized as the following lessons learnt.In the Vistula Region, nutrient emissions have levelled off but shortage of freshwater is critical. Forestry in the Dalälven watershed is largely environmental-friendly, except for fragmentation of the landscape and its negative impact on biodiversity. In the Archipelago area a former low-energy community has been replaced by a leisure time society. Different types of tourism is developing, but despite this variety, an improved integration of ecological properties with socio-economic patterns is required in order to build a sustainable, living Archipelago. The lake Peipsi basin and the surrounding area suffer both from problems of resource management and economic backwardness. Parts of the local economy has lost access to the one time large Soviet market, although the Estonian side has apparently benefited from present economic growth. To cope with the division of the lake, a regime for trans-national management is unfolding. It is based on both informal and, to an increasing extent, agreed professional contacts.Networks of engaged people were in all sites a resource for and promoter of the sustainability path. In order to succeed and to maintain the zeal, they need strong institutional support and common goals. Public programmes in the Baltic, ie. the work of the Helsinki Commission and Baltic Agenda 21, have developed instruments to enhance sustainability beneficial for the management of these watersheds. But critical tasks remain to be done in developing a shared understanding of ways to improve management of ecosystems with social factors.     

Identification, definition and quantification of goods and services provided by marine biodiversity: implications for the ecosystem approach

This paper identifies and defines ecosystem goods and services provided by marine biodiversity. Case studies have been used to provide an insight into the practical issues associated with the assessment of marine ecosystem goods and services at specific locations. The aim of this research was to validate the definitions of goods and services, and to identify knowledge gaps and likely difficulties of quantifying the goods and services. A validated theoretical framework for the assessment of goods and services is detailed, and examples of the goods and services at a variety of case study areas are documented. These results will enable future assessments of marine ecosystem goods and services. It is concluded that the utilisation of this goods and services approach has the capacity to play a fundamental role in the Ecosystem Approach, by enabling the pressures and demands of society, the economy and the environment to be integrated into environmental management.     

Application of macrobenthos functional groups to estimate the ecosystem health in a semi-enclosed bay

In this study, the functional group concept was first applied to evaluate the ecosystem health of Bohai Bay. Macrobenthos functional groups were defined according to feeding types and divided into five groups: a carnivorous group (CA), omnivorous group (OM), planktivorous group (PL), herbivorous group (HE), and detritivorous group (DE). Groups CA, DE, OM, and PL were identified, but the HE group was absent from Bohai Bay. Group DE was dominant during the study periods. The ecosystem health was assessed using a functional group evenness index. The functional group evenness values of most sampling stations were less than 0.40, indicating that the ecosystem health was deteriorated in Bohai Bay. Such deterioration could be attributed to land reclamation, industrial and sewage effluents, oil pollution, and hypersaline water discharge. This study demonstrates that the functional group concept can be applied to ecosystem health assessment in a semi-enclosed bay.     

Composition, Abundance and Stratification of Macrobenthos in the Marine Area Impacted by Tar Aggregates Derived from the Haven Oil Spill (Ligurian Sea, Italy)

The impact of tar aggregates deriving from the Haven oil spill that occurred in 1991 on the soft-bottom macrobenthos off Arenzano (Ligurian Sea, NW Mediterranean; Italy) was investigated in this study. Core samples were collected to evaluate the composition, abundance and stratification of macrobenthos in three contaminated and three control sites. The distribution of tar aggregates (often settled by hydroids, bryozoans and serpulids) in the impacted area did not show distinct patterns related to sediment depth. The macrobenthos was numerically dominated by polychaetes, followed by crustaceans (amphipods, isopods and tanaids) and sipunculids, whereas bivalve molluscs were less represented. Ophiuroids and nemerteans were only occasionally found. Stratification was the main factor explaining the distribution of benthic invertebrates, highest abundances being observed in the upper 5 cm of sediment, while densities of individuals declined sharply in deeper sediment layers. No significant differences were observed in the abundance of both the whole benthic assemblage and of the main benthic taxonomic groups between contaminated and control sites. The higher abundance of sipunculids at the contaminated sites, instead, was attributed to the availability of empty tubes of polychaetes in which they take refuge. The polychaetes/amphipods ratios did not show strong differences between impacted and control sites. Multivariate analysis (MDS) showed a wide scattering among deep bottom samples and a comparatively high similarity among intermediate and superficial layers, regardless of the contamination level. In conclusion, the results reported here suggest that tar aggregates do not determine appreciable detrimental effects on the soft-bottom macrobenthos, which appeared to have recovered towards natural pristine conditions.     

The dynamics of mountain erosion: Cirque growth slows as landscapes age

Glacial cirques are widely used palaeoenvironmental indicators, and are key to understanding the role of glaciers in shaping mountain topography. However, notable uncertainty persists regarding the rate and timing of cirque erosion. In order to address this uncertainty, we analyse the dimensions of 2208 cirques in Britain and Ireland and model ice accumulation to investigate the degree of coupling between glacier occupation times and cirque growth. Results indicate that during the last ~120 ka, cirques were glacier-free for an average of 52.0 ± 21.2 ka (43 ± 18%); occupied by small (largely cirque-confined) glaciers for 16.2 ± 9.9 ka (14 ± 8%); and occupied by large glaciers, including ice sheets, for 51.8 ± 18.6 ka (43 ± 16%). Over the entire Quaternary (i.e. 2.6 Ma), we estimate that cirques were glacier-free for 1.1 ± 0.5 Ma; occupied by small glaciers for 0.3 ± 0.2 Ma; and occupied by large glaciers for 1.1 ± 0.4 Ma. Comparing occupation times to cirque depths, and calculating required erosion rates, reveals that continuous cirque growth during glacier occupation is unlikely. Instead, we propose that cirques attained much of their size during the first occupation of a non-glacially sculpted landscape (perhaps during the timeframe of a single glacial cycle). During subsequent glacier occupations, cirque growth may have slowed considerably, with the highest rates of subglacial erosion focused during periods of marginal (small glacier) glaciation. We propose comparatively slow rates of growth following initial cirque development because a ‘least resistance’ shape is formed, and as cirques deepen, sediment becomes trapped subglacially, partly protecting the bedrock from subsequent erosion. In support of the idea of rapid cirque growth, we present evidence from northern British Columbia, where cirques of comparable size to those in Britain and Ireland developed in less than 140 ka. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.     

Characterization of organic matter in marine sediments to estimate age offset of bulk radiocarbon dating

Radiocarbon dating of Arctic marine sediment is often challenging due to the low availability of calcareous fossils. Consequently, bulk organic matter dating has at times been used to establish sediment core chronologies. Yet, radiocarbon dates based on bulk organic matter often appear to deviate vastly from dates based on fossils, mainly caused by input of allochthounous carbon, including terrigenous organic matter. In this study, we aim to examine the link between the composition of the bulk organic matter and the age offsets between the bulk radiocarbon dates and those obtained from calcareous foraminiferal tests. All samples are taken from the marine sediment core AMD14-204C from offshore Upernavik (eastern Baffin Bay). The radiocarbon dates for bulk organic matter are on average ∼3000 years older than the radiocarbon dates based on foraminifera, but with changing age offsets throughout the record. To investigate the cause of this age offset and its variations over time, we applied core scanning, X-ray Fluorescence analysis, stable isotopes, organic pyrolysis and microscopic organic petrology to examine the distribution and characterization of the organic matter. The results show that the older organic matter includes clastic input of reworked sedimentary rocks potentially originating from West Greenland and/or the Canadian Arctic Archipelago. Changes in the input of contemporary marine algal produced organic matter versus both terrigenous input and reworked ancient organic matter appear to control the age offsets between the bulk and foraminifera dates. A low Hydrogen Index and low δ¹³C_org values together with a high Oxygen Index, indicative of high influence of terrigenous organic matter, seem to correspond to samples with the largest age offsets; 1000–2000 years greater than in other samples. To examine the cause of the variations in the age offsets, a new quantification of the autochthonous organic matter as a fraction of the TOC was calculated. This shows that samples with the largest age offsets contained the lowest fraction (as low as ∼12%) of autochthonous organic matter in the TOC.     

Numerical models of continental and submarine erosion: application to the northern Ligurian Margin (Southern Alps,France/Italy)

We present a new numerical surface process model allowing us to take into account submarine erosion processes due either to submarine landslides or to hyperpycnal currents. A first set of models show that the frequency of hyperpycnal flows influences the development of submarine canyons at the mouth of continental rivers. Further experiments show that an increase in submarine slope leads to faster regressive canyon erosion and a more dentritic canyon network, whereas increasing the height of the unstable sediment pile located on the shelf break leads to wider and less dendritic canyons. The models are then applied to the western segment of the north Ligurian margin (northwestern Mediterranean), which displays numerous submarine canyons with various sizes and morphologies. From west to east, canyon longitudinal profiles as well as margin‐perpendicular profiles progressively change from moderately steep, concave‐up shapes to steeper linear to convex‐up shapes suggesting increasing eastward margin uplift. Moreover, the foot of the margin is affected by a marked slope increase with evidences of mass transport due to landslides. Numerical models which reproduce well the North Ligurian margin morphologic features indicate that the western part of the margin is submitted to rather low (i.e. 0.4 mm yr^?1) uplift and intense submarine erosion due to frequent hyperpycnal currents, whereas the eastern part bears more rapid (i.e. 0.7 mm yr^?1) uplift and has little or no hyperpycnal currents. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of ecosystem services: A case study in the middle reach of the Heihe River Basin,Northwest China

Ecosystem services evaluation aims at understanding the status of ecosystem services on different spatial and temporal scale. In this paper, we selected the middle reach of the Heihe River Basin (HRB), which is the second largest inland river basin in China, as one of the typical area to estimate the ecosystem services values (ESVs) corresponding to the land use changes. Based on the land use data and ecosystem service value coefficients, the total ecosystem services values (TESVs) of the middle reach of the HBR are quantitatively calculated, which were 9.244 × 108, 9.099 × 108, 9.131 × 108 and 9.146 × 108 USD in 1988, 2000, 2005 and 2008 respectively. During 1988–2008, the decrease of grassland, forest land, water area and unused land contributed 148.94%, 57.85%, 87.87% and 16.42% respectively to the net loss of TESVs, while the dramatic increase of cultivated land improved the TESVs with contribution of −211.08% to the net loss of TESVs. Expansion of cultivated land, which especially caused the loss of grassland and forest land, directly exerted negative impacts on the provision of ecosystem services in the study area. The findings of this research indicated that land use change was an important form of human activities, which had a strong impact on ecosystem services.     

Regional and interannual variability of ecosystem dynamics in the Southern Ocean

To investigate regional and interannual variability of the ecosystem in the Southern Ocean, a coupled circumpolar ice–ocean–plankton model has been developed. The ice–ocean component (known as BRIOS-2) is based on a modified version of the s-coordinate primitive equation model (SPEM) coupled to a dynamic–thermodynamic sea-ice model. The biological model (BIMAP) comprises two biogeochemical cycles – silica and nitrogen – and a prognostic iron compartment to include possible effects of micronutrient limitation. Simulations with the coupled ice–ocean–plankton model indicate that the physical–biological interaction is not limited to the effect of a varying surface mixed-layer depth. In the Pacific sector, large anomalies in winter mixed-layer depth cause an increased iron supply and enhance primary production and plankton biomass in the following summer, whereas in the Atlantic sector variability in primary production is caused mainly by fluctuations of oceanic upwelling. Thus, the Antarctic Circumpolar Wave (ACW) induces regional oscillations of phytoplankton biomass in both sectors, but not a propagating signal. Furthermore, interannual variability in plankton biomass and primary production is strong in the Coastal and Continental Shelf Zone and the Seasonal Ice Zone around the Antarctic continent. Interannual variability induced by the ACW has large effects on the regional scale, but the associated variability in biogenic carbon fluxes is small compared to the long-term carbon sequestration of the Southern Ocean.     

Source models for the 1993 Hokkaido Nansei-Oki earthquake tsunami

A source model for the 1993 Hokkaido Nansei-Oki tsunami must satisfy certain conditions. Such conditions are presented in this paper, and two methods are used to determine the best source model for this event. A trial-and-error method selects DCRC-17a as the best among 24 different models. This model has three fault planes dipping westward. To reproduce well the tide gauge records at two locations, an inversion analysis is used to modify the dislocation of DCRC-17a.     

Metallothionein in intestine of red mullet, Mullus barbatus as a biomarker of copper exposure in the coastal marine areas

Dietary metal exposure in fish is studied in native red mullet, Mullus barbatus, involving metallothionein (MT) response in the intestine, a primary site for metal uptake. Intestinal MTs (microg mg(-1) proteins), total proteins (mgml(-1) S50), Cu, Zn, Fe, Mn and Cd (microg ml(-1) S50) are considered as indicators of metal exposure in specimens from near-shore and off-shore locations of the Eastern Adriatic Sea. Metallothionein and Cu are statistically significantly higher in 68 specimens from the Kastela Bay, a near-shore area (30.0+/-6.71microg MT mg(-1) proteins; 0.30+/-0.08microg Cu ml(-1) S50), in comparison to 51 specimens from off-shore area, Solta Island (25.9+/-4.21microg MT mg(-1) proteins; 0.26+/-0.09microg Cu ml(-1) S50). Cytosolic Cu, a MT inducer, is significantly correlated (p<0.05, r=0.44) with MT in specimens from the Kastela Bay, independent on fish biometry. Our study indicates that cytosolic intestinal Cu and MT represent a measurable biochemical response in red mullet specimens, dwelling above sediments contaminated with Cu.     

Numerical determination of residence time and age in a partially mixed estuary using three-dimensional hydrodynamic model

This paper documents a numerical modeling study to calculate the residence time and age of dissolved substances in a partially mixed estuary. A three-dimensional, time-dependent hydrodynamic model was established and applied to the Danshuei River estuarine system and adjacent coastal sea in Taiwan. The model showed good agreement with observations of surface elevation, tidal currents and salinity made in 2002. The model was then applied to calculate the residence time and age distribution response to different freshwater discharges with and without density-induced circulations in the Danshuei River estuarine system. Regression analysis of model results reveals that an exponential equation can be used to correlate the residence time to change of freshwater input. The simulated results show it takes approximately 10, 4.5, and 3 days, respectively, for a water parcel that has entered the headwaters of the estuary to be transported out of the estuary under low, mean, and high flow conditions with density-induced circulation. The calculated age with density-induced circulation is less than that without density-induced circulation. The age of the surface layer is less than that at the bottom layer. Overall the study shows that freshwater discharges are the important factors in controlling the transport of dissolved substances in the Danshuei River estuarine system.     

基于综合指标法的鄱阳湖生态系统健康评价

由于湖泊生态问题日益突出,湖泊生态系统安全状态已经成为人们关注的热点问题,了解湖泊水生态系统的状况并根据湖泊生态系统健康状况开展精准治理和生态修复与保护尤为重要。本文基于对鄱阳湖及其流域生态环境的长期监测数据和资料收集,采用综合指标体系法,从物理形态、水文、水环境、水域生态、湿地生态和社会服务6个方面构建了鄱阳湖生态系统健康评估的指标体系,主要涵盖了湖泊口门状况、“五河”入湖径流变异程度、入湖河流水质达标率等26个指标。依据设置的阈值等级得到鄱阳湖生态系统健康评价各层次健康状况等级,通过对各湖泊生态系统各指标得分进行加权计算,得出生态系统健康评估准则层和目标层的得分,最终对鄱阳湖生态系统健康进行了客观的评价。结果表明,构建的湖泊生态系统健康评价体系针对性强、科学全面、具有可操作性,可为鄱阳湖及类似通江湖泊的生态系统健康评价提供案例和方法借鉴。评价结果表明鄱阳湖健康体征状况目标层得分为73.45分,评价结果为亚健康,鄱阳湖水生态系统健康主要受泄流能力、水文节律变化、富营养化程度和物种多样性的影响。最后根据鄱阳湖的水生态系统健康评分等级探讨了鄱阳湖水生态系统中亟需解决的问题,针对性地提出了...     

南海北部海底热流测量及分析

广州海洋地质调查局用德国产的微型温度传感器和自行研制的重力取样器组装成海底热流探针,并用该设备在中国南海北部开展了海底热流测量,这是国内首次独立开展此项工作,也是我国海洋地质和地球物理调查技术方法的新尝试.通过实测数据分析以及与1985年中美合作获得的西沙海域地热流测量剖面数据对比,表明测量数据可靠并具有良好的一致性.此项工作的成功,将有助于地热流测量工作的深入开展,进而提高我国海底天然气水合物的勘探和海洋地质基础研究的水平.     

The determination of the best fitting and the extreme source models by a global inversion method

In this paper, a global inversion method is developed for seismic moment tensor inversion by using the body wave forms. The algorithm depends on neither the selection of starting model nor the forms of objective function and constraints. When the error function, measure of the difference between the observed and synthetic waveforms, is chosen as the objective function, the best fitting source model is found; when a certain combination in seismic moment tensor elements is selected as the objective function and the values of error function are constrained in a suitable bound, the extreme source models can be produced by minimizing or maximizing this combination. By changing the form of the combination of moment tensor elements, a variety of different source characteristics can be considered. Therefore the extreme solution provides an estimation of the uncertainty in the best fitting source model. The seismic waveform data was used to evaluate the effectiveness of this algorithm. This research was supported by the National Natural Science Foundation of China.     

The ecosystem of a mesotrophic lake-I. Simulating plankton biomass and the timing of phytoplankton blooms

The response of plankton biomass in Lake Mjøsa, Norway, to changes in exogeneous factors during the years 1976–87 is studied by using a simulation model of the lake ecosystem. The model includes mechanisms required to test the Sverdrup hypothesis for the initiation of the spring phytoplankton bloom, and it includes zooplankton grazing and thermocline erosion which is important factors contributing to the formation of a second autumn bloom. The model describes 45% of the observed inter annual variance in chl-a, but only the right order of magnitude for the zooplankton biomass. The model describes 35% of the variance in the timing of the onset of phytoplankton growth (p = 0.03) and 41% of the variance in the timing of the second bloom (p = 0.07). However, 4 of 12 simulated annual time series showed only one bloom. The OECD regression model for chl-a as a function of TP concentration and flushing rate explained 50% of the variance in chl-a, but a zooplankton regression model did not explain the observed variance in zooplankton biomass. A published regression model for the timing of the spring bloom gave a negative correlation with the observed bloom.