Input of terrestrial material into coastal Patagonian waters and its effects on phytoplankton communities from the Chubut river estuary (Argentina)

VIZZO, JUAN I.; CABRERIZO, MARCO J.; VILLAFAÑE, VIRGINIA E.; HELBLING, E. WALTER

Anthropogenic pollution of aquatic ecosystems

Springer

Año: 2021; p. 131 - 155

Riverine and eolian-dust inputs to coastal waters are influenced by bothrainfall and land-use (i.e., deforestation, agriculture, urbanization). Transport ofsediments and nutrients from rivers to the oceans are well- documented worldwide,and it is of major management concern because coastal ecosystems provide a greatvariety of products and services to humankind. Episodic, but extreme rainfall ordust-storm events can generate abrupt pulsed riverine/eolian discharge events, thusincreasing nutrients and sediments in surface waters. It is expected that they will beintensified in the upcoming decades by global change, but we scarcely know howthey could impact on coastal planktonic communities. In this chapter we address themain terrestrial material transported via rivers and winds in Patagonian coastalwaters of the South West Atlantic Ocean (SWAO) and their impact on the structureand functioning of phytoplankton communities. The rivers in Patagonia carry notonly sewage from the cities that lie on their margins, but also heavy loads ofnutrients, due to agricultural and cattle raising activities upstream from theirmouths; extreme rainfall events increase these inputs manyfold. Eolic inputs arealso important over Patagonia because this area has a strong prevalence of winds from the west, carrying a wide variety of particles that are blown far into the ocean,especially after volcanic eruptions. We used the Chubut river estuary (Patagonia) asa reference coastal ecosystem in the SWAO to assess how riverine and eolic inputsimpact on phytoplankton which are the base of one of the most productive fisheriesareas of the SWAO. Overall, nutrient inputs of terrestrial origin, improved phytoplankton growth, photosynthesis performance and changed the community structure towards a dominance of mostly nanoplanktonic diatom species . Theseresponses, however, might vary due to the interaction of terrestrial material inputswith other global change drivers such as warming, acidification, vertical mixing orsolar ultraviolet radiation