environment words | Lewis Stagnetto
MARINE NUISANCES Macro algae and factors that induce growth
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than 5oC from summer to winter. Water is he marine environment hosts a specific structures like roots, stems and huge variety of algal species most leaves, all of which are visibly absent from also not an issue as seaweed grows in it. of which are too small to see with seaweeds. You could argue that kelp is the By contrast, light attenuation in the oceans the human eye. They are there, algae that most resembles modern teris highly variable according to the seasons however, in greater numbers restrial plants but to claim that kelp and this can have a crucial impact on than we can imagine and has leaves, is to misunderstand the suitable habitats for algal growth. GenOur beach modern satellites have been subtle ties of algal growth. erally speaking, the more light the better, activities a key component in lifting the until algal cells reach their light saturation bring us into lid on their secretive world. point. Once reached, extra light will not aid One key difference is that seaweed contact with Our beach activities bring us absorbs nutrients from the surround- growth. Green algae have the highest light both the micro ing water. Terrestrial plants can only into contact with both the saturation point followed by brown algae and macro micro and macro algae but and finally, red algae. do this at their roots and leaves, algae... we only ever notice the larger whilst algae absorb them from all types. Macro algae is comparts. The cells that make up algae Like terrestrial plants, algae require nutrimonly referred to as seaweed and some are unspecialised, jacks of all ents which they take directly from the large volumes of it brought a poignant trades, whilst masters of none. surrounding water and here we have Seaweed issue to the surface, excuse the pun, over But this difference is important another key factor which determines absorbs the course of last summer. to facilitating seaweed to grow growth. Eutrophication is a term used nutrients at unprecedented rates providto describe high levels of these nutrifrom the But what exactly is seaweed? In terrestriing that all conditions are right. ents in water bodies; it is more comsurrounding monly referred to as water pollution. al terms, we can simply call them plants water. because they photosynthesise and are The level of eutrophication is the main So, what are these conditions? autotrophic (they get their energy from the Temperature variability in the factor in determining an algal bloom sun). However, the difference is greater size, with higher levels promoting faster ocean is much more stable than on land growth. The main nutrients for growth are than the similarity. Terrestrial plants have and in the Mediterranean, this varies less
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GIBRALTAR MAGAZINE FEBRUARY 2017