The marine ecosystem occupies almost the entire hydrosphere. The sea constitutes a single ecosystem, albeit of immense size, part of the biosphere itself considered as the largest ecosystem. Practical reasons for study lead and restrict this concept to entities that are more easily investigated.
In its simplest definition, an ecosystem is the product of an active interpenetration and interaction of a biotope and a biocenosis. By biotope we mean the inorganic fraction, i.e. the seabed, water, currents, winds, etc. the organic fraction by biocenosis.
This consists of the subsystem of producers, which in the sea are bacterioplankton, phytoplankton and macrophytic algae, and the subsystem of consumers made up of the animal world. On the sidelines there are the breakers who, at different levels, convert the organic matter into forms that can be reused by photosynthetic organisms and / or consumers.
The production of organic compounds in the ocean is limited to photic and shallow areas. In this surface water layer and in littoral areas, carbon dioxide is fixed by photosynthesis and nutrients are incorporated into living tissues.
The organisms that carry out this production are the tiny organisms of phytoplankton and macrophytic algae. Plankton is the direct food source for herbivorous species, while macrophytic algae contribute to the biocenosis basically as detritus.
Marine biodiversity conservation
The study: Marine biodiversity conservation, published on the Current biology, explained: "Marine biodiversity is the essential foundation for the structure and functioning of ocean ecosystems and for providing the full range of ecosystem services that benefit humans on local, regional, and global scales.
These benefits include many visible as well as unseen functions and services such as the oxygen we breathe, the seafood we eat, the support of local livelihoods, the marine plants storing blue carbon and protecting our shorelines, the medical and biochemical compounds found in marine species, the coral reefs we explore when scuba diving, and the charismatic creatures inspiring our lives.
All these benefits are provided by the diversity and interplay of ocean life, from tiny plankton and bacteria to 30 meter whales and giant kelp."