Search

Some basic principles to enlarge simple ecological models and the role of nonlinearities are discussed. The inclusion of internal groups and the new dynamic possibilities associated with this procedure are considered in the context of the logistic model. According to our results, processes like the success or extinction of a particular group without affecting the global population are not necessarily linked to the impact of environmental changes or the supremacy of a determined group or subspecies. In our case, the uniformity, the success or extinction of a particular group into a global population may be seen as the possibility to achieve or not a typical symmetry-breaking process. Such possibilities arise associated with the degree of nonlinearity contributions and the specificities of the interaction network in the model. Other elements linked with the ecological interaction, the role of symmetries and the phenomenological nature of ecological modelling are also discussed.

The Gulf of Ana Maria is located in the southeast Cuban platform and is one of the most important regions for fisheries in the country. Taking into account that marine primary production defines the areas and yields of fishery production, we develop a habitability index that quantifies the environmental suitability for phytoplankton assemblage development. The index considers light and limiting nutrient as the main environmental factors governing the phytoplankton primary production in the Gulf of Ana Maria. We considered a function of radiation described by a photosynthesis model and function of nutrient described by a eutrophication index. Quantitative estimates of habitability were made in nine stations at 1:00 PM and 4:00 PM for a typical day of October, in order to match with the available field data. Solar irradiation at sea surface was calculated by using the tropospheric ultraviolet and visible computational code TUV4.6, and we derived the data of attenuation coefficient of light from Secchi depth data. Besides, we used nutrient concentration of soluble reactive phosphorus (limiting nutrient). We obtained the first optical classification of the waters of the Gulf of Ana Maria, with a dominance of coastal water C5. It was found an intermediate potential (~50%) for phytoplankton development in the Gulf of Ana Maria, which is mainly limited by nutrients rather than by light. Further refinements in both the index and data collection are expected to reach more accurate conclusions.

The activity of anammox bacteria (AA) can be estimated based on the production of \({\text{N}}_{2}\). Known the mechanism of the catabolic reaction, three differential equations are established according to the most important substrates (\({\text{NO}}_{3}^{ - }\) and \({\text{NH}}_{4}^{ + }\)) and the pH. The solution of this system might provide a rough estimate of the activity of the anammox, since neither inhibitory effects nor efficiency of the microorganisms is considered. Anammox can be inhibited by ocean acidification, generated by the deposition of \({\text{H}}_{2} {\text{SO}}_{4}\) and \({\text{HNO}}_{3}\) during asteroid impact events such as Chicxulub. The magnitude of the inhibition depends on the amount and speed with which the \({\text{H}}_{2} {\text{SO}}_{4}\) is added fundamentally.

In this chapter, we outline general ideas to quantify habitability, starting with a general abiogenesis–biogenesis conceptual model. We connect this model with the approach of the astrobiological school of quantitative habitability, specifically with quantitative habitability theory, to devise habitability indexes. We present two indexes devised by us: the Aquatic Primary Habitability for photosynthesis-based ecosystems, and the Chemosynthetic Habitability Index for chemoautotrophy-based ones. As a case study, we present the application of the last one to hydrothermal vents. It is also mentioned the possibility of embedding parameters such as net primary productivity, calculated using habitability indexes, into greater ecological models with several trophic models, making a clear connection between the astrobiological and ecological approaches of quantitative habitability.

The Cuban archipelago has an extremely complex geology. In this chapter, an overview on its peculiarities is given. It is also presented a historical sketch of the Cuban geological heritage, and the current menaces to preserve it. Then, the current Cuban policy and practical efforts for geoconservation are described.