Spatio-temporal variation of subtidal meiofauna in a sandy beach from Northeastern Venezuela. Meiofauna organisms that play an important role in the trophic ecology of soft bottom benthos, have short life cycles and they respond quickly to disturbance and pollution. The present study shows the spatio-temporal variation of subtidal meiofauna (metazoans passing a 500µm sieve but retained on meshes of 40-63µm) in four shallow subtidal stations. Samples were taken in the sandy beach of San Luis, in the Northeastern coast of Venezuela, from October 2005 until September 2006. For this, three replicate sediment core samples (4.91cm 2), were collected monthly to a depth of 10cm into the sediment, and preserved in 6% formalin stained with rose Bengal. Specimens of 14 meiofaunal groups (Foraminifera excluded) were collected, being the nematodes, ostracods and harpacticoid copepods the most abundant. Monthly density was comprised between 64 and 503ind./10cm 2 , and mean density of stations between 173 and 449ind./10cm 2. There is a trend of low densities from October to February (end of the rainy season until the middle of the dry season). The San Luis beach control of the meiofaunal community is shared by climatic conditions and by the biology of the species found. The meiofauna mean density in San Luis beach (263ind./10cm 2) was low when compared to other studies in tropical areas. Rev. Biol.

Seasonal variations of polychaetes in a Thalassia testudinum bed were studied from June 2000 to April 2001 in Chacopata, northeastern Venezuela. Eight replicate samples were taken monthly with a 15 cm diameter core and the sediment was passed through a 0.5 mm mesh sieve. A total of 1 013 specimens, belonging to 35 species, was collected. The monthly density ranged from 387 ind/m 2 (September) to 1 735 ind/m 2 in May ( X = 989±449 ind/m 2 ). Species richness was lowest in August and September (8)

Polychaetes (Annelida: Polychaeta) epibiont on Spondylus americanus (Bivalvia: Spondylidae) from Mochima National Park, Venezuela. The polychaetes epibiontic on the mollusk Spondylus americanus Hermann, 1781 were extracted from mollusks hand-collected at a depth of 10-30 m in Mochima National Park, Venezuela (10º21'00" N -63º23'36" W), using scuba diving gear. Forty-three polychaete species were identified on the 32 bivalve specimens analyzed.

Ecuador is crossed by a network of rivers that originate mainly in the high Andean reliefs and pour into two basins: Amazon and Pacific. Many suffer from severe human impact. The main objective of the present study was to assess water quality of Mojarrero stream using biotic indices (BMWP/Col. and Shannon-Wiener index) as a tool to evaluate ecosystem health. During June, August and October 2014, bottom samples were taken at three stations. Each month and season three replicates of benthic aquatic invertebrates were taken on sandy-stony bottoms with a 0,3 mm mesh “D-net”. The fauna was represented by eleven orders and 29 families. The most abundant order was Coleoptera, representing 42,70% of total collected organisms, followed by Diptera (19,01%) and Ephemeroptera (11,38%). The most abundant family was Elmidae, with 568 individuals, (37,37% of total organisms), followed by Chironomidae (11,38%) and Baetidae (7,24%). Shannon diversity values ranged between 0,98 bits/ind. (June, EST. 2) and 2,23 bits/ind. (October, Est 1). The BMWP/Col. index values indicate that the river has a good environmental health on the high and low sections. The median section has some pollution, particularly during August and October.