Determination of the Fish Community Structure of an Intertidal Rocky Zone of the Pacific Coast of Baja California Sur

The intertidal zone (also known as seashore) are transition areas between land and sea, that are greatly influenced by the tide cycle, therefore, environmental parameters, such as temperature and salinity, oscillate according to the periods in which these areas are exposed to air. Intertidal zones are highly diverse, which makes them key ecosystems for the development of sea life (both flora and fauna) exposed to drastic environmental change. The 59 visual censuses campaigns were carried out during the full moon of each month from 2015 to 2019. Temperature, salinity and dissolved oxygen were recorded during each visual census and showed variations between years. Temperature showed two distinct seasons, warm and cold. A total of 14,995 organisms were recorded, belonging to 30 species, 28 genera, 15 families, five orders and one class. Ecological indices like species richness (SR), Shannon-Wiener’s diversity (H') and Fisher’s alpha (α-Fisher) showed significant differences between years, 2015 and 2016 recorded as the most diverse years, while the lowest values were recorded in 2019. Therefore, fish communities of tide pools showed to be highly diverse, with 30 species recording similar relative abundances, and according to the BVI, only 11 species were dominant. Spatio-temporal variations of temperature, salinity and dissolved oxygen were highly correlated to changes in fish community structure, and the dominance of certain species, which are of great importance for the structure and dynamic of the tide pool communities. Therefore, the aim of the present study was to determine the fish community structure of tide pools during the low tide in the intertidal zone of a locality known as El Faro, on the west coast of La Paz, B. C. S., Mexico.

The Conidae Family (Snails Producers of Poisons) Associated with the Rocky Intertidal Zone of Acapulco, Mexico

Acapulco, Mexico has a coastline of 62 km where large areas of rocky substrate inhabited by organisms such as the GASTROPODA Class can be found. Conidae (Fleming, 1822) Family is among the members of this Class, which has been poorly studied in the Mexican Pacific, despite their biomedical potential. This research was carried out in the rocky intertidal of nine sites in Acapulco. The objectives were: 1) Prepare an inventory of species associated with rocky intertidal of Conidae family, 2) examine the composition of the family based on two criteria: a) species richness and b) abundance, 3) determine the geographical distribution and 4) analyze the size composition. The unit sampled was 1 m2 and the sampled area was 10 m2 persite. A total of 97 organisms were analyzed, corresponding to two subfamilies, five genera and five species. The Puncticuliinae (Tucker & Tenorio, 2009) subfamily had higher species richness, abundance and frequency of occurrence. The most abundant and most common species were Harmoniconus nux (Broderip, 1833) and Gladioconus gladiator (Broderip, 1833) both showed regular distribution. The size structure found for Conidae family is similar to what has been reported in other research. For the first time G. gladiator is being reported for the state of Guerrero.

Mollusks of the Rocky Intertidal Zone at Three Sites in Oaxaca,Mexico

The community of mollusks at three rocky intertidal zone in Oaxaca, Mexico was analyzed. Two samplings per site were conducted. At each sampling the inspected area was 10 m2. The sampling unit was 1 m2. 5862 specimens were examined. 68 mollusks species were identified. The families better represented in species richness were: FISSURELLIDAE, MURICIDAE, LOTIIDAE, MYTILIDAE, CHAMIDAE, ISCHNOCHITONIDAE y CHITONIDAE. The species that had the greatest density were Lottia discors, Siphonaria palmata, Lottia acutapex, Chormoytilus palliopunctatus, Brachidontes adamsianus, Chton articulatus e Ischnochiton muscarius. The species with the widest distribution represent 11.76%. With irregular distribution was found in 58.82% of the species. The gastropod Crucibulummonticulus, the bivalve C. palliopunctatus and the polyplacophoran C. articulatus had the greatest size. The value of diversity index was H’ = 4.29 bits/ind. and J’ = 0.72. The mollusks community in the rocky intertidal zone study sites is characterized by small size, because they rarely exceed seventy millimeters. The values of H’ and J’ indicate that the mollusk community in the study area has a high diversity and high uniformity, corresponding to mature and stable communities in a tropical region.

New Records for GASTROPODA Class of Species Found in the Rocky Intertidal Zone of the Marine Priority Region 32,Guerrero,Mexico

The GASTROPODA class, one of the best known marine environments, is formed by a large number of species and the shape of their shell structure varies greatly. These mollusks are distributed from the intertidal zone all the way to the abyssal zone, and there are also swimming and floating species. This research was conducted at seven sites, located in the Marina Priority Region 32 (MPR 32), located in the State of Guerrero, Mexico. The aim of this report is to document the scope of the geographic distribution of the 34 species of GASTROPODA class. 11,263 total specimens were analyzed. 108 species were identified, of which four species are new records for Mexico, 15 for the Transitional Mexican Pacific, 11 for the State of Guerrero and four for the MPR 32. Here we report a significant number of new records of species of class GASTROPODA found on the rocky intertidal zone of the MPR 32. The reporting of these new records, demonstrates the need to focus research efforts on the study of marine diversity, since knowledge in this respect is quite incomplete, especially regarding marine mollusks, a fact that has been reported by the National Commission for the Management and Use of Biodiversity.

Modern sedimentation rates in the intertidal zone on the west coast of the Bohai Gulf

On the basis of the measurement of 210Pbex and 137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43-4.06 cm/a, and is within the range of 0.65￣1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a. The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s, and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedi- mentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.

Rocky Desertification Risk Zone Delineation in Karst Plateau Area:A Case Study in Puding County,Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China.The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention.We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification.The potential risk of rocky desertification was quantified with the factor-weights union method and statistical analysis method.Five grades of rocky desertification risk were delineated based on Geographic Information System.The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively.As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area.However, more than half of the area(about 50.81%) was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification.Rocky desertification risk was higher in the southeast and lower in the northwest of the study area.Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.

Geochemical Characteristics of Rare Earth Elements in Intertidal Sediments of Tianjin Coastal Zone

The geochemical characteristics of rare earth elements (REEs) in intertidal sediments in Tianjin coastal zone were systematically studied. The environmental behaviors of REEs in polluted river were also examined. The source of REEs in intertidal sediments was discussed on the basis of distribution pattern of REEs. The results can be summed up in the following aspects: (1) The average content of total REEs in the intertidal sediments is 164.5 mg·kg -1, and different in different sections of the coast. (2) Residual REEs in the coastal zone decrease from north to south, and Fe-Mn oxides and organic matter-bound REEs increase. Compared with those in Changjiang River, ratio between residual and carbonate REEs is obviously low. (3) Distribution patterns of REEs show that light REEs is relatively high and Eu-anomaly is slightly negative. They are similar to the patterns in coastal and inland rivers and different from those in continental shelf.

Enoplus taipingensis,a new species of marine nematode from the rocky intertidal seaweeds in the Taiping Bay,Qingdao

One new species of free-living marine nematodes Enoplus taipingensis sp. nov. from the rocky intertidal seaweeds in the Taiping Bay, Qingdao is described and illustrated with scanning electron microscopy observation and 18S rRNA gene sequence analysis. Enoplus taipingensis is characterized by special arrangement of lateral setae on the tail, three cervical setae, distal structure on the supplement, and much longer body length with bigger De Man ratio ＂a＂. Type specimens are deposited in the College of Marine Life Science, Ocean University of China.

Investigation of Macrobenthos in the Intertidal Zone of Tianjin and Discussion on Bioremediation

An investigation of macrobenthos in the littoral zone was carried out in Tanggu District, Tianjin City in June 2003. This investigation was the only integrated one since 1983 there. Something about macrobenthos investigation was reported in this paper. The results showed that the biomass of macrobenthos of that area was almost at the same level as that of 1983, and the density of macrobenthos increased a little. The biomass of Mactra veneriformis has great effect on the average biomass of that area. The diversity of macrobenthos has changed obviously, and 5 or 6 kinds of macrobenthos have become extinct or decreased greatly. So the ecological structure of macrobenthos has become simpler and unstable. In addition, some ecological methods to remedy the area are discussed in this paper.

A study on nano－ and microdiatoms in the intertidal zones of Zhongshan Station，Antarctica

The present paper deals with the composition and distribution of nano-and microdiatoms in sands and grits covered by ice and snow in the intertidal zones of the Zhongshan Station in Larsemann Hills (69°21'～69°25'S, 76°00'～76°25'E ), East Antarctica. The samples were collected from seven sand-grit flat stations in January 1989 and February 1990. The highest cell density of nano-and microdiatoms occurred at Station B. The cell concentration was 0. 8×103～3651×103 cells per gram sand in January 1989 and 4. 5×103～2618×103 cells Per gram in February 1990 respectively.The nano-and microdiatoms in the intertidal zones were small in cell size and high in abundance. The dominant species was Navicula glaciei.

Comparison of the Macrozoobenthic Community and Sedimentary Environment with and Without Horseshoe Crab Presence in the Crocodile Island Intertidal Zone,Xiamen,China

In order to compare the macrozoobenthic community and sedimentary environment with and without the presence of horseshoe crabs,the benthic macrofauna,sediment grain size,chromium(Cr),cobalt(Co),nickel(Ni),polycyclic aromatic hydrocarbon(PAHs),organic carbon and nitrogen were seasonally investigated at site A(with horseshoe crab presence),sites B and C(without horseshoe crab presence)in the Crocodile Island intertidal zone in Xiamen from June 2018 to July 2019.The results showed that most of the community parameters of benthic macrofauna,population parameters of common benthic macrofauna and environmental parameters were significantly different at the sites with horseshoe crab versus non-horseshoe crab sites.A two-way ANOVA test showed that the densities of Ceratonereis erythraeensis and Sigambra hanaokai had significant site variation.Cluster and nonmetric multi-dimensional scaling(NMDS)analysis showed the community composition of benthic macrofauna was significantly different among the three sampling sites over four seasons.The mean sand content at site A(64.32%)was higher than those at site B(36.01%)and site C(18.86%).Conversely,the mean contents of silt,clay,Cr,Co,Ni,organic carbon,organic nitrogen,phenanthrene,and pyrene at site A were lower than those at site B and site C.These observations are consistent with the expected preferences of horseshoe crabs to live in areas with 60%sand content,which is associated with abundant and edible clamworms in the Crocodile Island intertidal zone,Xiamen.

Species Composition and Diversity of Macrobenthos in the Intertidal Zone of Xiangshan Bay,China

Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs(bivalves and gastropods), crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, Ilyplax tansuiensis, and Cerithidea cingulata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index(H') had its maximum(2.45) in section QJ, and minimum(1.76) in section TG. Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiangshan Bay have been disturbed by human activities, especially at the interior bay.

Species Distribution, Diversity, and Abundance of Sea Cucumbers in Tropical Intertidal Zones of Aurora, Philippines

The distribution, diversity, and abundance of sea cucumbers in intertidal zones of Aurora were studied from February to June 2013 to obtain baseline data. A one-hour timed-search survey covering an approximate one kilometer over a ten-meter wide area was conducted in six coastal municipalities to obtain a comprehensive list of sea cucumber species found in the zones. Only four sampling stations (Baler, Dipaculao, Dilasag, and Dingalan) were selected for belt transect survey, 50 × 50 m, based on the availability of coralline, sandy, muddy sand, and rocky habitats which were laid perpendicular and parallel to each intertidal zone. Timed-search survey revealed a total of 15 species of sea cucumbers distributed among two Orders (Order Aspidochirotida and Order Apodida) and four Families (Family Holothuriidae, Family Stichopodidae, Family Synaptidae, and Family Chirotidae) were recorded. Synapta maculata is most common and has widespread distribution. Belt-tranect surveys showed Holothuria leucospilota is among the most frequently occurring species both during day time (58%) and night time (75%). The Dilasag sampling station had the most diverse species (0.71) while the Dipaculao sampling station had the densest species of Holothuria leucospilota (10,014 in∙ha−1) and abundant (95.91%) species.

Taxonomic Composition and Spatial Distribution of Meiofauna Community from a Sandy Intertidal Zone in Sishili Bay, Yellow Sea Coast (Northern China)

The meiofauna composition and trophic groups of the nematode communities have been studied at a sandy intertidal zone in Sishili Bay along the Yantai coast(Yellow Sea,China).Nematoda was dominant among the 11 groups of meiofauna.The meiofaunal densities were low,ranging between 111±47 and 542±131 ind./10 cm^(2).Results obtained from the correlation analysis made it possible to determine several factors that influence species composition and distribution.Generally,sediment granulometry significantly affected the communities.The highest abundance was found in fine-grained sediments(318.77±126 ind./10 cm^(2))com-pared to coarse-grained sediments(175±82 ind./10 cm2).Nematodes were predominant in all studied sites.A total of 70 species be-longing to 52 genera and 18 families were identified in the study area.There was a significant difference in nematode abundance(ANOVA,F=2.38,P<0.05)between the three sites.Nematode communities were characterized by a high level of species diversity in sediments composed mainly of very-fine sands(>63μm),with dominant species belonging to the genus Bathylaimus,Ptycho-laimellus,Spirinia,and Sabatieria.The trophic groups were dominated by non-selective deposit feeders(40.7%)and epistrate feed-ers(41.29%).In contrast,the species composition in medium grain sands was characterized by a low species diversity index and a high Simpson dominance index.Nematode communities showed similar dominant species compositions belonging to a single genus Bathylaimus,Enoplolaimus,and Oncholaimus,and in terms of trophic structure-representatives of deposit feeders(46.15%),preda-tors,and omnivores(64.71%)prevailed.The divergence of meiofaunal community structures can be explained by abiotic factors such as sediment grain size,salinity,and organic carbon content.Specifically,sediment particle size can explain the diversity of nematodes at the level of in abundance,diversity indices,and trophic structure.The highest nematode density and diversity coincided with the highest percentage of very fine sands.

Laboratory simulation of soil respiration response to environmental conditions in intertidal zones of Jiangsu Province,China

As major contributor to the blue carbon sink,intertidal zones play a crucial role in the global carbon cycle.In recent years,more attention has been given to the carbon cycle in intertidal wetlands.However,due to highly variable and uncertain environmental conditions,it is difficult to clarify the quantitative relationship between soil respiration and environmental factors through in-situ experiments.In this study,the response of soil respiration characteristics to variations in the temperature and water table was investigated using a monitoring apparatus of CO_(2)flux at the soil-air interface in the intertidal zone.The results showed that soil respiration flux was significantly correlated with temperature,and the correlation best fitted the DoseResp function.Meanwhile,the respiration flux was enhanced with the descent of water table,a relationship could be described by a quadratic function.The effect of the water table on soil respiration became more pronounced with the rise of temperature.These results provide significant clarification of the impact of human activities on the carbon cycle in bare intertidal zones and as well as support for numerical simulations of the carbon cycle in bare intertidal zones.

The pigmental composition and the absorption spectral analysis of Ulothrix sp．and benthic diatoms in the intertidal zone of Great Wall Station，Antarctica

This paper reports the results of the absorption spectral analysis of Ulothrix sp. attached to the rocks from the intertidal zone in front of Great Wall Station,Antarctica in February 1989,and the benthic diatoms growing on small stones and on the edge of swamps of that zone.Six kinds of pigments were separated and identified in benthic diatoms.They are carotene, chlorophyll-a, fucoxanthin, chlorophyin, neoxanthin and chlorophyll-c. Nine kinds of pigments were identified in Ulothrix sp.. They are carotinoid, pheophytin, chlorophyll-a, -b, chlorophyllin, chlorophyllide-a, neoxanthin, chlorophyll-c and pheophytin-c. The intertidal benthic diatoms and Ulothrix sp. have specific absorption spectra and there are also marked differences in the composition of algal pigments they contain. Since the pigments of marine algae show differences in their absorption spectra, the absorption spectrum can be used to identify the species of marine algae.

Sand Grain Size and Organic Matter Concentration in the Intertidal Zones on the Southwest Coast of Taiwan

From April 2013 to April 2014, the average pH and water temperature of the Taisi oyster cultivation area (TS, Yunlin County, Taiwan) were 8.05 (7.35 - 8.45) and 24.7˚C (13.7˚C - 32.8˚C) (N = 8226) The average organic matter (OM) concentration at sites TS-A and TS-B were 6.9% ± 1.3% and 6.9% ± 1.2%, and the weight of drift sand was 40.3 ± 19.1 g/d/m2 and 28.5 ± 34.3 g/d/m2 (N = 27). Considerable sand drifting typically occurs during the southwest monsoon season in summer. The average OM concentration at five dunes from Zhuoshui estuary to Zengwun estuary was 23.9 ± 4.5 g/kg. The percentage of sand grain weight of 0.15 - 0.25 mm and 0.25 - 0.60 mm was 82.5% ± 14.2% and 10.5% ± 12.0%. In the spring and autumn of 2015, the average OM concentration at the eight intertidal zones from Hanbao to Cigu was 49.8 ± 34.1 g/kg (N = 177), and the OM concentrations at Huwei estuary and Hanbao and Fangyuan intertidal zones were relatively high. The OM concentration (95.3 ± 75.7 g/kg) of the low tide zone of Huwei estuary was the highest among all tidal zones. The OM concentration during spring (59.4 ± 41.7 g/kg, N = 95) was higher than that in autumn (39.1 ± 17.8 g/kg, N = 84). For sand grain size ranges 0.15 - 0.25 and 0.063 - 0.15 mm, the weight ratio of intertidal sediment was 39.4% ± 26.9% and 27.6% ± 20.1%, respectively. The broad and flat intertidal zone was marked by fine sand and long intertidal zone;the weight ratio of SGSs < 0.25 mm exceeded 65%, and the OM concentration was between 20 and 30 g/kg. Coastal habitat diversity creates differences in biological communities, especially among crabs and benthic organisms. A greater understanding of coastal environments can aid in the management of coastal wetlands.

Residues of organochlorine pesticides in intertidal flat surface sediments from coastal zone of Jiangsu Province, China

Sixteen surface sediment samples were collected and analysed to evaluate the residues of organochlorine pesticides(OCPs) from intertidal flat in Jiangsu Province. Overall, 22 OCPs were detected with total concentrations of OCPs ranging widely from 0.96 to 12.14 ng/g(dry wt). Total hexachlorocyclohexane(HCH) and total dichlorodiphenyltrichloroethane(DDT) levels varied from <0.01 to 0.67 ng/g and from 0.23 to 4.85 ng/g, respectively. DDTs were the predominant compounds. The dominance of β-HCH indicated a history of HCH pollution. According to the ratios of( p, p'-DDD+ p, p'-DDE)/ p, p '-DDT and o, p ′-DDT/ p, p ′-DDT, new input of DDTs did not occur in most sites, and the main sources were historical usage of technical DDTs. OCPs such as dieldrin, endrin, p, p ′-DDD, and p, p ′-DDT exceeded the effects range low, showing adverse biological effects that would occasionally occur at some sites of the study area.

云南省岩溶地区石漠化土地治理分区研究

根据云南省岩溶地区石漠化土地空间分布特征和各区域地质地貌、气候、水文、岩溶土壤和森林植被分布,结合碳酸盐岩的类型、岩性组合特征、不同岩溶地貌对区域环境和水土资源的制约、石漠化在不同地貌条件下的形成和发育特征,统筹考虑岩溶生态系统的完整性、地理单元的连续性和经济社会发展的可持续性等因素,将全省88个岩溶监测县划分为6个治理区,并就各分区地理区位、地质地貌、成土母岩、水文、气候类型、森林植被类型分布以及各石漠化区不同类型岩溶土地面积占比等进行描述。

砂质海岸底栖硅藻的研究进展

文章综述了国内外关于砂质海岸底栖硅藻的研究进展。作为砂质海岸主要的植物群,底栖硅藻通过一系列机制以适应多变的沙生环境。在潮间带的沉积物中,底栖硅藻是初级生产力和沙滩食物网的重要组成部分。沉积物、温度、盐度、光照、营养盐和生物因素等等都会对底栖硅藻的生长和群落分布产生影响。近年来,陆续有了关于我国潮间带底栖硅藻群落分布特征的研究,但总体来说,关于沙生境底栖硅藻的研究相对较少,需要进一步的调查以完善我国的硅藻生态学研究。