Plankton dynamics in the Mar Piccolo of Taranto: a pilot plan

Abstract

An integrated sampling of both active (cells in water column) and resting stages (cysts sinking to the bottom) of phytoplankton, was carried out on March 1996 in the Mar Piccolo of Taranto. At least 46 taxa were recognized in the water column. Cyst sinking rate was about 23,000 m^-2 d^-1. Out of 37 recognized morphotypes, mainly dinoflagellates, 18 were previously unrecorded from the area. The present sampling represents the preliminar test to outline an experimental design to an integrated study of plankton dynamics.     

L'“Artemisia Verlotorum„ lamotte a roma e in altre località italiane

Acacia saligna is a phanerophyte native to Australia; it was introduced in the 1950s in Sardinia (Italy) for afforestation mainly in coastal areas and at present it is considered naturalized, becoming invasive in sand dune habitats. Seed biology is one of the most important factors contributing to the invasion success of Australian acacias, for this reason the germination ability is an important issue when trying to clarify the invasion dynamics of A. saligna. Germination tests were conducted at the BG-SAR, testing the effect of different temperatures and percentages of NaCl, on seeds belonging to five accessions from four populations of two coastal habitat types. The optimal temperature range for seed germination was 15–20°C; the increase of salt caused a decrease in the final germination percentages. At 1% of NaCl concentration, germination fell at 25–30°C and at 2% it was relatively low (below 40%) and occurred almost only at 15°C. This work represents a contribution to the knowledge of the seed ecology and germination behaviour of the species, providing new data on the interpopulation and interannual variability, and relating them to the invasion dynamics of A. saligna in the coastal Mediterranean habitats.     

Spatial variability of soil salinity in Bohai Sea coastal wetlands,China: Partition into four management zones

Soil salinization constitutes an environmental hazard worldwide. The Bohai Sea coastal wetland area is experiencing dramatic soil salinization, which is affecting its economic development. This study focused on the spatial variation and distribution characteristics of soil salinity in this area using geostatistical analysis combined with the kriging interpolation method, based on a large-scale field investigation and layered soil sampling (0–30, 30–60 and 60–100 cm). The results revealed that soil salinity in these layers demonstrated strong variability, obvious spatial structure characteristics and strong spatial autocorrelation. Soil salinity displayed a significant zonal distribution, gradually decreasing with increasing distance from the coastline. Apart from the northern part of the study area, which appeared to be not affected by soil salinization, there were varying degrees of soil salinization in nearly 70% of the total area. With increasing soil depth, the areas of non-salinized and mild salinized soil gradually decreased, while those of moderate salinized and strong salinized soils increased. The area of saline soil first decreased and then increased. The study area could be divided into four management zones according to soil salinities in the top 1-m soil body, and utilization measures, adapted to local conditions, were proposed for each zone. The results of our study present an important theoretical basis for the improvement of saline soils, for wetland re-vegetation and for the sustainable utilization of soil resources in the Bohai Sea coastal wetland.     

Ecological niche modeling of coastal dune plants and future potential distribution in response to climate change and sea level rise

Climate change (CC) and sea level rise (SLR) are phenomena that could have severe impacts on the distribution of coastal dune vegetation. To explore this we modeled the climatic niches of six coastal dunes plant species that grow along the shoreline of the Gulf of Mexico and the Yucatan Peninsula, and projected climatic niches to future potential distributions based on two CC scenarios and SLR projections. Our analyses suggest that distribution of coastal plants will be severely limited, and more so in the case of local endemics (Chamaecrista chamaecristoides, Palafoxia lindenii, Cakile edentula). The possibilities of inland migration to the potential ‘new shoreline’ will be limited by human infrastructure and ecosystem alteration that will lead to a ‘coastal squeeze’ of the coastal habitats. Finally, we identified areas as future potential refuges for the six species in central Gulf of Mexico, and northern Yucatán Peninsula especially under CC and SLR scenarios.     

Ecomarkets for conservation and sustainable development in the coastal zone

Because conventional markets value only certain goods or services in the ocean (e.g. fish), other services provided by coastal and marine ecosystems that are not priced, paid for, or stewarded tend to become degraded. In fact, the very capacity of an ecosystem to produce a valued good or service is often reduced because conventional markets value only certain goods and services, rather than the productive capacity. Coastal socio‐ecosystems are particularly susceptible to these market failures due to the lack of clear property rights, strong dependence on resource extraction, and other factors. Conservation strategies aimed at protecting unvalued coastal ecosystem services through regulation or spatial management (e.g. Marine Protected Areas) can be effective but often result in lost revenue and adverse social impacts, which, in turn, create conflict and opposition. Here, we describe ‘ecomarkets’ – markets and financial tools – that could, under the right conditions, generate value for broad portfolios of coastal ecosystem services while maintaining ecosystem structure and function by addressing the unique problems of the coastal zone, including the lack of clear management and exclusion rights. Just as coastal tenure and catch‐share systems generate meaningful conservation and economic outcomes, it is possible to imagine other market mechanisms that do the same with respect to a variety of other coastal ecosystem goods and services. Rather than solely relying on extracting goods, these approaches could allow communities to diversify ecosystem uses and focus on long‐term stewardship and conservation, while meeting development, food security, and human welfare goals. The creation of ecomarkets will be difficult in many cases, because rights and responsibilities must be devolved, new social contracts will be required, accountability systems must be created and enforced, and long‐term patterns of behaviour must change. We argue that efforts to overcome these obstacles are justified, because these deep changes will strongly complement policies and tools such as Marine Protected Areas, coastal spatial management, and regulation, thereby helping to bring coastal conservation to scale.     

THE HABITATS AND HABITAT PREFERENCES OF CLARIAS GARIEPINUS (PISCES: CLARIIDAE) IN A CLEAR COASTAL LAKE (LAKE SIBAYA,SOUTH AFRICA)

SUMMARY

The habitat preferences of the sharptooth catfish, Clarias gariepinus, in a clear coastal lake, Lake Sibaya, are described. Larval and small juvenile catfish inhabit flotsam and the rootstocks of plants in very shallow marginal areas. Larger juveniles inhabit densely-vegetated marginal pools, and may venture into open areas at night. Adult catfish (over 350 mm TL) occupy offshore areas, where their density is highest in terrace and sheltered bay habitats, and least in slope and profundal habitats. Adult catfish undergo a diel migration into shallow water at night and into deeper water during the day which is more marked at low lake levels. The methods used to capture catfish, and the main habitats in Lake Sibaya, are also described.     

Paleontological completeness of the record of lower tertiary mollusks,U.S. Gulf and Atlantic coastal plains: Implications for phylogenetic studies

Choice of method in phylogenetic analysis should involve some consideration of the quality or completeness of the available fossil record. If it is poor, cladistic methods are preferable; if it is good, stratophenetic methods may be valid. A concept of paleontological completeness, defined herein, is useful for judging the quality of a given fossil record. This paper considers eight possible measures of paleontological completeness, and evaluates their value as phylogenetically useful estimates of the quality of the fossil record. Of the eight measures, Sadler‐Schindel type analysis of stratigraphic completeness and analysis of geographic ranges appear to be the most useful and reliable. The remaining six are useful only as rough approximations of the quality of the record, or as supporting evidence for conclusions based on other methods. Use of these eight measures on the lower Tertiary molluscan record of the U.S. Gulf and Atlantic coastal plains indicates that this record is approximately 30–50% complete. This is probably not complete enough to trust purely stratophenetic approaches to phylogenetic analysis, but is too complete to ignore the record in favor of a purely atemporal, cladistic approach. The concept of paleontological completeness may be useful in estimating the quality of this and other fossil records for non‐phylogenetic purposes, such as studies of evolutionary rates and diversity and extinction patterns.     

滇西北高原碧塔湖滨沼泽植物群落分布与演替

滇西北高原碧塔海湖滨带狭长型沟谷和宽广型沟谷设置了两条沼泽研究样带,研究了沼泽群落种类组成特征、群落分布与演替规律及其驱动因素.结果表明:两条样带总计调查到43种植物,隶属21科35属;群落中均以稀有种占多数,但总体上狭长型沟谷沼泽群落的均匀程度高于宽广型沟谷;α多样性各指数与沼泽水位均呈显著正相关,但β多样性与沼泽水位无相关性;沿水分梯度,沼泽群落呈现出挺水植物群落→沼泽植物群落→沼泽化草甸植物群落的生态序列分布,但是也在局部微地形作用下形成群落复合体;生态序列分布与湖岸特点和沟谷类型有关:狭长型沟谷具有陡坡湖岸,沼泽群落倾向于间断分布,宽广型沟谷具有缓坡湖岸,沼泽群落倾向于连续分布.以水分因子为主、以地形等因子为辅的综合环境因素是决定碧塔海湖滨沼泽群落植物多样性和生态序列分布格局的驱动因素,相应地植物群落演替特点为渐变式演替和跳跃式演替两种模式并存,但演替方向一致.     

胶州湾近岸浅水区鱼类群落结构及多样性

根据2009年3月-2010年2月在胶州湾西北部近岸浅水区进行的鱼类逐月定置网调查数据,采用生态多样性指数和多元统计分析等方法研究了该海域的鱼类群落结构及多样性特征.结果表明:调查共鉴定出44种鱼类,其中海洋性27种,河口性鱼类17种.鱼类种类组成与底层水温和盐度有密切关系.胶州湾近岸浅水区鱼类群落Margalef种类丰富度指数(R)变化范围为0.33-3.50,Shannon-Wiener多样性指数(H’)为0.42-2.25,Pielou均匀度指数(J’)为0.23-0.93.聚类分析(CLUSTER)和多维标度排序(MDS)分析表明,不同鱼类种类组成的各月份样品可划分为3个组分:水温较低的冬季组G1(12月-翌年4月)、水温次高的春秋季组G2(5-6月、10-11月)和水温最高的夏季组G3(7-9月).其中G1的典型种主要为尖海龙(Syngnathus acus)、方氏云鳚(Enedrias fangi)和玉筋鱼(Ammodytes personatus)等冷温性常栖类群种类,G2的主要典型种为鳀鱼(Engraulis japonicus)和尖海龙,G3的主要典型种为鲐鱼(Scomber japonicus)、细条天竺鱼(Apogonichthys lineatus)和普氏缰虾虎鱼(Amoya pflaumi)等洄游性鱼类.单因子相似性分析(ANOSIM)表明,3个月份组间鱼类群落结构差异显著,不同月份组间两两差异均显著.生物-环境分析(BIOENV)表明,底层水温是影响胶州湾近岸浅水区鱼类群落结构时间变化的主要环境因子.在胶州湾内近岸浅水区发现40余种幼鱼,但占优势的主要为低值鱼类,表明胶州湾的产卵、肥育场功能有所下降,应加强胶州湾近岸水域生态环境和渔业资源的保护及修复.