ALBERT

Description: Freshwater ecosystems are the most threatened ecosystems worldwide. Argentinian-protected areas have been established mainly to protect vertebrates and plants in terrestrial ecosystems. In order to create a comprehensive biodiverse conservation plan, it is crucial to integrate both aquatic and terrestrial systems and to include macroinvertebrates. Here, we address this topic by proposing priority areas of conservation including invertebrates, aquatic ecosystems, and their connectivity and land uses. Location: Northwest of Argentina. We modeled the ecological niches of different taxa of macroinvertebrates such as Coleoptera, Ephemeroptera, Hemiptera, Megaloptera, Lepidoptera, Odonata, Plecoptera, Trichoptera, Acari, and Mollusca. Based on these models, we analyzed the contribution of currently established protected areas in the conservation of the aquatic biodiversity and we propose a spatial prioritization taking into account possible conflict regarding different land uses. Our analysis units were the real watersheds, to which were added longitudinal connectivity up and down the rivers. A total of 132 species were modeled in the priority area analyses. The analysis 1 showed that only an insignificant percentage of the macroinvertebrates distribution is within the protected areas in the North West of Argentina. The analyses 2 and 3 recovered similar values of protection for the macroinvertebrate species. The upper part of Bermejo, Salí-Dulce, San Francisco, and the Upper part of Juramento basins were identified as priority areas of conservation. The aquatic ecosystems need special protection and 10% or even as much as 17% of land conservation is insufficient for species of macroinvertebrates. In turn the protected areas need to combine the aquatic and terrestrial systems and need to include macroinvertebrates as a key group to sustain the biodiversity. In many cases, the land uses are in conflict with the conservation of biodiversity; however, it is possible to apply the connectivity of the watersheds and create multiple-use modules. We proposed priority areas of conservation including invertebrates, aquatic ecosystems, and their connectivity and land uses. Also, we analyzed the contribution of currently established protected areas in the conservation of the aquatic biodiversity.

Description: The role of zooplankton in microbial nitrogen turnover in marine environments is poorly understood. Here, we present results from two experiments designed to determine the excretion rate of ammonium and dissolved organic nitrogen (DON) by dominant copepods, Acartia tonsa and Paracalanus cf indicus , fed with two natural sized-fractioned diets (20–150 μm and 〈 20 μm), and its possible effects on the transcriptional activity of ammonia monooxygenase subunit A ( amoA ), a functional marker for ammonia-oxidizing archaea (AOA) and bacteria (AOB), as a response to the input of ammonium and DON by copepod excretion, during autumn and winter in central/southern Chile. Our results reveal that DON was the main excretion product, with rates up to 3.7 μmol L −1 h −1 . DON production increased in copepods fed with the small-sized food. Ammonium was also excreted, with rates up to 0.08 μmol L −1 h −1 in autumn and 0.4 μmol L −1 h −1 in winter, and rapidly consumed by the microbial community, decreasing down to 0.07 μmol L −1 between the initial time to 4 h. Ammonium consumption coincided with increased AOB and AOA amoA transcript copies in copepods fed with the larger-sized food, while a different microbial community, probably heterotrophic, reacted to nitrogen input via excretion by copepods fed with the smaller-sized food in autumn. AOA-A was transcriptionally active in winter with nearly zero ammonium concentration, suggesting that AOA outcompete AOB when ammonium becomes limited. We conclude that nitrogen excreted by copepods can be used directly by microbial communities, including nitrifying ones. Zooplankton excretion may thus provide significant remineralized nitrogen for new and regenerated production in the upper ocean.