Photosynthesis starts when a photon- a tiny packet of light is absorbing a molecule of chlorophyll.
Answer:
Rapid increases in water temperature cause extensive fish kills
Explanation:
Biotic factors are all living organisms that contribute to an ecosystem. On the other hand, abiotic factors are non-living factors, such as climatic factors (temperature, rainfall, wind), edaphic factors (soil type, soil texture, soil aeration etc). Changes of abiotic factors can have a huge influence on living organisms of ecosystem. The effects might be benefical or harmful.
Some of the most common abiotic factors that can impact a marine ecosystem are water temperature, currents, light, alkalinity, oxygent concentration etc.
<span>Damming a river has a variety of effects on the freshwater ecosystem, more than just altering the flow from A to B. Dams create calm bodies of water, changing overall temperature regimes and sediment transport, leading to conditions which tend to favour generalist species. Loss of specialist species, particularly endemics, changes the community structure and leads to biotic homogenization. A dam will withhold sediment in the reservoir, not just decreasing the amount of substrate available to local freshwater species, but even impacting diadromous, estuarine and marine species much further downstream. The competition between resident species for food and breeding sites will increase as damming isolates populations, and perhaps more importantly, damming completely restricts migratory fish species. Isolation may lead to decreases in genetic diversity and therefore puts species at greater risk from disease. All of these effects may be exacerbated by changes in the surrounding land use. Overall, damming river flow will lead to both a loss of native species, but also an increase in exotic species which are more likely to become established in degraded habitats. For this reason, dams are one of the greatest global threats to freshwater biodiversity.</span>
