Ocean biology

Suspended particles with a size 20 pm sink very slowly ( 1 m d ) whereas particles as large as 100 pm in diameter, usually fecal pellets, can sink as rapidly as 100 m d.  

Heterotrophic bacteria exist throughout the ocean both as individual entities in seawater (c. 80%) and attached to particle surfaces and sediments. These bacteria consume dissolved organic matter because they have no means other than dissolved transport across 

Photoautotrophic flagellates are pico to nanometer-sized plankton, usually with two flagella, whip-like appendages that beat within grooves in the cell wall. They are found in most regions of the ocean. 

Scanning electron micrographs of (A) a diatom frustule (opal), diameter c.20 pm  

The presence and distribution of phytoplankton in the sea is determined primarily by the abundance of chlorophyll. Although this is not a direct measure of the number of cells, because they contain different amounts of chlorophyll under different conditions, it is the most rapid and widely used method of identifying the presence of photosynthetic organisms. Because the color of the ocean can be determined by satellites, it is possible to determine the global content of chlorophyll in the sea over one optical depth, about the first 30 m of surface waters. 

---

Oceanic biology is a sink for atmospheric CO2 because of the involvement of the aqueous form of this gas in planktonic photosynthesis. This complex process can be summarized by... 

Table I. Summary of ocean biological productivity (from 27)...

Recently, the ocean-basin distribution of marine biomass and productivity has been estimated by satellite remote sensing. Ocean color at different wavelengths is determined and used to estimate near-surface phytoplankton chlorophyll concentration. Production is then estimated from chlorophyll using either in situ calibration relationships or from empirical functional algorithms (e.g., Platt and Sathyendranth, 1988 Field et al., 1998). Such studies reveal a tremendous amount of temporal and spatial variability in ocean biological production. 

Because of the role these algae play in the oceans biological productivity and their impacts on climate due to the removal of carbon dioxide, satellite sensors have been employed to measure the chlorophyll a contents in oceans, lakes, and seas to indicate the distribution and abundance of biomass production in these water bodies. Detection is set at the specific reflectance and absorption wavelengths of the light from the upper layer of the ocean where photosynthesis occurs. 

Fisheries and Environmental Sciences, Department of Fisheries and Oceans, Biological Station, St. Andrews, New Brunswick, EOG 2X0 Canada... 

Yvon-Lewis, S. A., and J. H. Butler, The Potential Effect of Oceanic Biological Degradation on the Lifetime of Atmospheric CH3Br, Geophys. Res. Lett., 24, 1227-1230(1997). 

Santosa, S.J., Mokudai, H., Takahashi, M. and Tanaka, S. (1996) The distribution of arsenic compounds in the ocean biological activity in the surface zone and removal processes in the deep zone. Applied Organometallic Chemistry, 10(9), 697-705. 

Figure 5.3. Schematic representation of the ocean biological pump. From Usbeck (1999).

Estuaries and the mouths of large river systems are located at an important interface between land and ocean where terrestrially derived materials can be altered before entering continental shelves. Continental shelves provide an estimated net CO2 sink of 0.1 Pg C y 1 (lPg = 1015g), with an export that may be as much as 20% of the oceanic biological pump (Liu et al., 2000). Unfortunately, ocean margins have only recently started to receive the appropriate attention they deserve in the context of their importance in the global C budget (Bauer and Druffel, 1998 Liu et al., 2000) (more details on this in chapter 16). 

Steinberg, D. K., Carlson, C. A., Bates, N. R.,Johnson, R.J., Michaels, A. F., andKnap, A. H. (2001). Overview ofthe USJGOFS Bermuda Atlantic Time-series Study (BATS) A decade-scale look at ocean biology and biogeochemistry. Deep Sea Res. II48, 1405—1447. 

We thank two anonymous reviewers for their constructive comments. Y.G. was supported by the following programs The US NASA Ocean Biology and Biogeochemistry Program (Award NNG04G091G). 

Siever R. (1991) Silica in the Oceans biological-geochemical interplay. In Scientists on Gaia (eds. S. Schneider and P. Boston). MIT Press, pp. 287-295. 

After the first appearance of cyanobacteria, presumably in microbial mats, the arrival of unicellular cyanobacterial plankton must surely have been rapid. In the modern warm tropical and subtropical oceans, cyanobacterial picoplankton are ubiquitous (Capone et al. 1997), supporting complex microbial consortia, and in the Archaean they could have formed the upper 100 m layer of an open ocean biological community, which may have had great diversity (Karl 2002). Archaeal plankton would have been out-competed for occupancy of the topmost levels, but could have occupied a now more productive underlying lower layer, 100-300 m thick, dependent on the redox debris (including dissolved chemical species) from the overlying oxygenic photosynthesizers. The immediate results. 

Links between the Archaean atmosphere and the ocean biology and temperature... 

---