Ecosystems in the Comau Fjord

Huinay estuary and Comau Fjord together summarize the general characteristics of fjord systems in northern Patagonia, which include:

(a) extensions of sedimentary marshes at the mouth of the rivers, creating estuarine systems highly effected by the tides.

(b) steep increases in depths along most walls of the fjord.

(c) evergreen arboreal vegetation that reaches to the high tide mark, contributing large volumes of organic material to the sea that are rapidly and efficiently recycled by marine organisms.

(d) absence of any direct oceanic swells, only low wind waves occurring.

(e) plentiful rainfall causing a freshwater surplus resulting in a low salinity surface layer in the fjord.

Oceanic waters with high salinity penetrate under layers of mixohaline surface waters, permitting the development of calm water fauna in scarcely lighted environments. Primary productivity is concentrated in the surface layer. Detrivorous and filtering organisms dominate below this layer, along with their associated chain of predators.  

The most studied areas of the fjord are along the edges, due to the limited access arising from the extreme depths quickly reached along the granitic walls. Areas of high diversity are characteristically linked with either vertical or overhanging portions, most likely due to a lack of sedimentation in these locations. One also observes an increase in diversity nearing the mouth of the fjord, where the superficial freshwater layer is much thinner.