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Zheng X.,State Oceanic Administration | Huang L.,Xiamen University | Li Y.,Hainan Marine Development Plan and Design Institute | Lin R.,State Oceanic Administration
Shengtai Xuebao/ Acta Ecologica Sinica

Marine algae vary considerably in their nutritional, chemical, and structural composition, thus providing a heterogeneous and variable food resource for marine herbivores. However, Due to seasonal fluctuation in species composition and abundance of marine algae, herbivores usually encounter the environments with little tasty, highly nutritional food. Because herbivores eat foods that are much lower in nutrients than their own tissues, they display a diversity of behavioral and physiological adaptations to cope with the low nutritional value of their foods. Selective feeding on more nutritious plants, increasing consumption of lower quality foods (compensatory feeding) have all been proposed as important behaviors allowing herbivores to obtain adequate nourishment. Amphipods were common benthic species in macroalgal-based communities. They may regulate the macroalgal community structure by their selective feeding behavior. This study investigated the feeding of amphipod Ampithoe valida on three dominant macroalgae (Ulva lactuca, Gracilaria tenuistipitata var. liui and Rhizoclonium sp.) of Yundang Lagoon, and analyzed how the nutritional quality in terms of dry mass/ wet mass (DM/ FM), total organic carbon (TOC), total nitrogen (TN), C/ N ratio and protein level may affect the food selectivity in the amphipod. The results showed that there was negative correlation between the feeding rates and the DM/ FM, or TOC/ FM of the macroalgae when macroalgae was separately offered to A. valida, indicating compensatory feeding behavior in the amphipod, that is, A. valida can use quantity to compensate quality when nutritional value of macroalgae was low. A. valida preferentially fed on U. lactuca and Rhizoclonium sp., and their feeding rates negatively correlated to the TOC concentrations or protein levels in the macroalgae. However, no relationship was found between the feeding rates and TN. These results suggest there are no predictable effects of the nutritional quality on the feeding selectivity of amphipods. However, although A. valida have strong preference to green algae, Yundang Lagoon doesn't structure a macroalgal community dominated by red algae G. tenuistipitata var. liui. Source

Bai X.,University of Michigan | Wang J.,National Oceanic and Atmospheric Administration | Schwab D.J.,National Oceanic and Atmospheric Administration | Yang Y.,University of Michigan | And 4 more authors.
Ocean Modelling

An unstructured Finite Volume Coastal Ocean Model was applied to all five Great Lakes simultaneously to simulate circulation and thermal structure from 1993 to 2008. Model results are compared to available observations of currents and temperature and previous modeling work. Maps of climatological circulation for all five Great lakes are presented. Winter currents show a two-gyre type circulation in Lakes Ontario and Erie and one large-scale cyclonic circulation in Lakes Michigan, Huron, and Superior. During the summer, a cyclonic circulation remains in Lakes Superior; a primarily cyclonic circulation dominates upper and central Lake Huron; Lake Ontario has a single cyclonic circulation, while circulation in the central basin of Lake Erie remains two-gyre type; Lake Michigan has a cyclonic gyre in the north and an anti-cyclonic one in the south. The temperature profile during the summer is well simulated when a surface wind-wave mixing scheme is included in the model. Main features of the seasonal evolution of water temperature, such as inverse temperature stratification during the winter, the spring and autumn overturn, the thermal bar, and the stratification during summer are well reproduced. The lakes exhibit significant annual and interannual variations in current speed and temperature. © 2013 Elsevier Ltd. Source

Mo W.,Sun Yat Sen University | Mo W.,Hainan Marine Development Plan and Design Institute | Wei X.,CAS South China Sea Institute of Oceanology | Qiu L.,Sun Yat Sen University | Qiu L.,Hainan Marine Development Plan and Design Institute
China Ocean Engineering

Because of the influence of human activities, the evolution of the Modaomen Estuary is no longer a purely natural process. We used a long-term morphodynamic model (PRD-LTMM-10) to study the evolution of the estuary from 1977 to 1988. The model incorporated modules for riprap-siltation promotion and waterway dredging. The model can simulate the morphodynamic evolutionary processes occurring in the Modaomen Estuary during the period of interest. We were able to isolate the long-term influences of various human engineering activities and the roles of natural factors in estuarine evolution. The governance projects had the largest effect on the natural development of the estuary, resulting in larger siltation on the west side. Installation of riprap and reclamation of submerged land resulted in scouring of the main Hengzhou Channel causing deep trough out-shift. Severe siltation narrowed the upper end of the Longshiku Deep Trough. © 2011 Chinese Ocean Engineering Society and Springer-Verlag Berlin Heidelberg. Source

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