Plankton open-water

Serrazanetti GP, Conte LS, Carpene E, et al. 1991. Distribution of aliphatic hydrocarbons in plankton of Adriatic sea open waters. Chemosphere 23 925-938. 

Taguchi, S., and Laws, E. A. (1988). On the microparticles which pass through glass fiber filter type GF/F in coastal and open waters. J. Plankton Res. 10, 999—1008. 

This is because in general, in the open waters the dominant organisms involved in the phytoplankton bloom are nano- and pico-plankton which do not have a siliceous skeleton. There are few siliceous phytoplankton within the winter phytoplankton bloom and even less during the spring-summer period which follows (see Section 4.4.2.2). 

Of small size, 0.5-10 cm, chaetognaths have an elongated shape composed of three parts the head, trunk, and tail. The last two parts are equipped with three pairs of flippers, which make the animal look like a vaned torpedo and allow fast movement in open water these animals are almost all planktonic. Carnivorous and voracious, chaetognaths capture their prey with chitin-ous hooks, and feed mostly on copepods, pelagic crustaceans, jellyfish, sometimes small fish, and even other chaetognaths. 

The differences between areas can possibly be explained, with several assumptions, in terms of plankton activity patterns. Based on the hypothetical model of Fig. 7, the most important source of organic ligands in these open ocean waters is the in situ production, originating from excretion products and/or intracellular fluids. The amount of ligands... 

Abstract Monitoring of Phaeocystis since 1948 during the Continuous Plankton Recorder survey indicates that over the last 5.5 decades the distribution of its colonies in the North Atlantic Ocean was not restricted to neritic waters occurrence was also recorded in the open Atlantic regions sampled, most frequently in the spring. Apparently, environmental conditions in open ocean waters, also those far offshore, are suitable for complete lifecycle development of colonies (the only stage recorded in the survey). 

Figure 21 Comparison of vertical distribution of biomarker and microbial abundances in oceanic water columns, (a) Contour plots of concentration (ngL ) of hexadecanoic acid, (b) Crenarcheol at various depths in the water column and distances from shore on a northwest-to-southeast transect off Oman in the Arabian Sea (after Sinninghe Damste et al, 2002). Hexadecanoic acid serves as a biomarker proxy for eukaryotic and bacterial biomass and clearly shows the expected surface maximum, with concentrations dropping off steeply with increasing water depth. In contrast, crenarcheol, a molecular biomarker for planktonic crenarcheota, shows two maxima with one near 50 m and the other —500 m. (c) Vertical distributions of microbial concentrations in the North Pacific subtropical gyre bacteria (solid squares) and planktonic crenarcheota (open squares). Effectively, there are two microbial domains which were determined using a DAPI nucleic acid stain (after Karner et al., 2001). These data show the increasing proportion of planktonic archea in deep waters, with the result that at depths greater than 2,000 m, the crenarcheota are as abundant...

Standard rRNA molecular phylogeny (Woese, 1987 Barnes et al, 1996 Stetter, 1996 Pace, 1997) implies the antiquity of hyperthermophile organisms. Though there has been much dispute about the rRNA interpretation, there is some consensus that, whether or not it is the very most ancient, life around hot-water vents is certainly of great antiquity. The implication is that by mid-Archean, hyperthermophile habitats around hot vents were populated by microbial mats, and the waters around hot vents were occupied by free-swimming cells. Mesophile prephotosynthetic plankton probably existed in the open seas, and, distal to the thermophile life in the surroundings of vents, the mesophile habitats further from the hot springs were also occupied. 

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