Effects of Soft Corals on Scleractinian Coral Recruitment. II: Allelopathy, Spat Survivorship and Reef Community Structure

Abstract. Two field experiments were performed on the Great Barrier Reef, Australia, at Orpheus Island and Lizard Island, respectively, to investigate the effects of allelopathic soft corals on survivorship and community structure of scleractinian coral spat. Ceramic tiles were placed around the allelopathic soft corals Sinularia flexibilis (Quoy & Gaimard 1833) and Sarcophyton glaucum (Quoy & Gaimard 1833), and controls. One control consisted of settlement plates surrounding a scleractinian coral (non‐allelopathic planktivore); another control had no adult soft or scleractinian coral present. The experimental soft corals affected the recruitment of various taxonomic groups of coral spat differentially, as evidenced by the diversity of coral spat settling in treatments and controls. At Orpheus Island (O.I., n = 1038 spat) and Lizard Island (L.I., n = 7032 spat), there were significant differences between recruitment success of the two dominant coral taxa, Pocilloporidae (O.I., 61.4 %; L.I., 20.5 %) and Acroporidae (O.I., 33.7 %; L.I., 53 %). Settlement plates exposed to Sinularia flexibilis at either site had the lowest proportion of acroporid recruits. Diversity indices (Shannon‐Wiener Indices) varied significantly between treatments at both Orpheus and Lizard Islands. This appears to be due to selective inhibition of acroporid spat by Sinularia flexibilis at both sites. Growth of coral spat was higher on settlement plates in the presence of Sarcophyton at Lizard Island. Settlement of most associated epibiota was generally inhibited under these conditions. Coral spat survivorship was highest in the presence of Sinularia at Orpheus ­Island; at Lizard Island, this was the case with the Sarcophyton treatment. Higher survivorship, and in some cases growth, of coral spat near soft corals was apparently due to reduced competition for space between spat and associated epibiota. This hypothesis is supported by the results of a sister experiment where a coating of Sinularia flexibilis extract on settlement tiles significantly decreased fouling by sessile epibiota. Soft corals have an allelopathic effect on recruitment and early development of scleractinian corals and, consequently, on early coral reef community succession.     

Polychaete Fauna of Seagrass Beds (Halodule wrightii Ascherson) Along the Coast of Rio de Janeiro (Southeast Brazil)

Abstract.  The polychaete community structure from six Halodule wrightii seagrass beds along the Rio de Janeiro coast (Southeast Brazil) was investigated. Variations in species diversity, overall density and species composition in relation to sediment grain size, seagrass biomass and selected plant structural features such as root and shoot length from the study sites were analysed. Ten core samples (0.02 m²) were randomly collected from each site. Three additional samples were taken for grain size analysis of sediment. Sixty-eight species of polychaetes belonging to 24 families were found. The dominant species as well as species composition varied greatly among sites, showing that a typical polychaete community does not exist. The number of species was positively correlated with the silt-clay percent and sorting coefficient of the sediment. A positive correlation between polychaete density and plant biomass was also obtained. Multivariate analysis indicated that polychaete communities were influenced greatly by seagrass plant features: plants with longer shoots harbour mainly surface-deposit feeders such as Magelona papillicornis , whereas plants with a higher root-shoot length relation sheltered mainly suspension or interface feeders like Fabricia filamentosa . This study demonstrates that granulometric properties as well as plant architecture play an important role in structuring the polychaete community. As the community-level response can reflect changes in local seagrass beds, the structure of the polychaete community can be an important indicator for management plans and the restoration of seagrass ecosystems.     

胶州湾春季大型底栖生物多样性及群落结构特征

基于2018年5月胶州湾海域共计20个站位所获取的生物及环境数据，研究胶州湾大型底栖生物多样性以及群落结构特征。调查海域共发现大型底栖生物208种，大型底栖生物总平均丰度和生物量分别为2 654.38 ind./m²和1 024.512 2 g/m²，大型底栖生物物种数、丰度和生物量均呈现北部高、南部低的分布趋势；调查海域优势种以多毛类为主，I_RI值最高的物种为菲律宾蛤仔Ruditapes philippinarum；香农维纳指数与ABC曲线均表明调查海域底栖生态环境整体清洁；在40%相似性水平上，可将调查海域大型底栖生物划分为4个群落；底温和底盐影响调查海域大型底栖生物丰度分布。     

Variability in plankton community structure, metabolism, and vertical carbon fluxes along an upwelling filament (Cape Juby, NW Africa)

The variability in dissolved and particulate organic matter, plankton biomass, community structure and metabolism, and vertical carbon fluxes were studied at four stations (D₁–D₄), placed along a coastal-offshore gradient of an upwelling filament developed near Cape Juby (NW Africa). The filament was revealed as a complex and variable system in terms of its hydrological structure and distribution of biological properties. An offshore shift from large to small phytoplankton cells, as well as from higher to lower autotrophic biomass, was not paralleled by a similar gradient in particulate (POC) or dissolved (DOC) organic carbon. Rather, stations in the central part of the filament (D₂ and D₃) presented the highest organic matter concentrations. Autotrophic carbon (POC_Chl) accounted for 53% (onshore station, D₁) to 27% (offshore station, D₄) of total POC (assuming a carbon to chlorophyll ratio of 50), from which nano- and pico-phytoplankton biomasses (POC_{A < 10 μm}) represented 14% (D₁) to 79% (D₄) of POC_Chl. The biomass of small hetrotrophs (POC_{H < 10 μm}) was equivalent to POC_{A < 10 μm}, except at D₁, where small autotrophs were less abundant. Dark community respiration (R_d) in the euphotic zone was in general high, almost equivalent to gross production (P_g), but decreasing offshore (D₁–D₄, from 108 to 41 mmol C m⁻² d⁻¹). POC sedimentation rates (POC_sed) below the euphotic zone ranged from 17 to 6 mmol C m⁻² d⁻¹. Only at D₄ was a positive carbon balance observed: P_g−(R_d + POC_sed) = 42 mmol C m⁻² d⁻¹. Compared to other filament studies from the NE Atlantic coast, the Cape Juby filament presented lower sedimentation rates and higher respiration rates with respect to gross production. We suggest that this is caused by the recirculation of the filament water, induced by the presence of an associated cyclonic eddy, acting as a trapping mechanism for organic matter. The export capacity of the Cape Juby filament therefore would be constrained to the frequency of the interactions of the filament with island-induced eddies.     

长门岩岛植物群落中的山茶现状和恢复措施

报告青岛市长门岩岛植物群落中的山茶现状。指出在我国分布最北边缘的常绿阔叶植物天然山茶，因人为破坏已濒临绝境。建议成立山茶自然保护区，并提出恢复山茶植物群落的措施。     

山东半岛东部海域诸岛潮间带底栖海藻的研究

报道山东半岛东部海域主要以威海市北面和南面８个岛屿春、秋两季期间带底栖海藻群落组成、生物量、季节变化及主要环境因子。在两季度月得到海藻８８种，秋季比春季种数多，北面４岛种类略多于南面４岛，群落构成都以红藻类为主。各岛平均生物量秋季高于春季，北面４岛高于南面４岛。就各岛生物量而言，北断面高于南断面。     

智慧农场在线综合服务平台系统的研究与设计

结合农场发展实际情况,提出智慧农场在线综合服务平台建设指导思想、建设原则、核心建设内容及建设与运行模式,剖析其实际的功能与性能需求。针对智慧农场建设内容,综合旅游、农田、社区、微信平台等方面,提出能适应功能需求不断变化的智慧农场在线综合服务平台系统架构,为智慧农场建设提供新的思路,以期为智慧农场信息服务标准化建设提供指导。     

基于RFID的三维GIS智慧小区应用平台建设研究

近年来,我国各地政府相继试点了一批"智慧社区",并在试点范围内开展了一系列"智慧社区系统"建设工作,但受建设成本、消费需求、技术规范、物联网设备种类的限制,使得各区域在"智慧社区"系统应用集成方面取得的进展不一致。如何保证各应用系统具有良好的可扩展性,如何使得RFID信息集成模式更加深入应用到智慧社区管理当中去,如何使RFID、GPS、RS、GIS、WCS更好的集成,以实现巡更管理及人员定位,这都是当前基于RFID的三维GIS智慧小区应用平台建设研发与探索的核心所在。基于此,本文从系统构架、应用实践效果等方面设计了三维GIS智慧小区应用平台,并重点阐述了系统的开放性与数据更新一致性。     

全球化背景下在华跨国移民社区的空间生产——广州远景路韩国人聚居区的案例研究

运用问卷和半结构化访谈的方法,梳理了远景路从城中村到跨国移民社区的空间生产过程。研究显示,广州远景路已形成以韩商为主的贸易产业链和韩国人与本地村民、外来人口混居的跨国移民社区,其中白云区政府、投资开发商和韩商三者共同参与,推动了远景路韩国人聚居区的空间形成。     

Exploring the Effectiveness of Outreach Strategies in Conservation Projects: The Case of the Audubon Toyota TogetherGreen Program

Successfully engaging target audiences represents a key challenge for environmental conservation projects. In this study, we examined 354 conservation projects implemented across the United States with the intention of systematically exploring the relationships between different forms of outreach (in particular, message content and delivery) and self-reported project outcomes. Using end-of-program retrospective surveys, we found that experiential engagement and directly demonstrating and/or communicating the ease of potential conservation actions were most consistently related to achieving desired project outcomes. Although it was thought to be largely effective by project managers, we found that focusing on equipping audiences with new knowledge was negatively related to conservation outcomes. Measured outreach variables explained between 15% and 17% of the variance in project outcomes, suggesting a wide variety of unmeasured factors at play. We discuss insights relevant to engaging target audiences in future U.S. conservation projects.