It’s a small world… or: Just because you can’t see it doesn’t mean it’s not there!
What are Protozoa ? <ul><li>Protozoa are single-celled organisms </li></ul><ul><li>One cell can perform all the living functions (feeding, movement, reproduction) multicellular organisms – such as worms or humans - need a large number of cells for </li></ul><ul><li>Protozoa have developed many different ‘ways of life’ (parasitic, free-living) in terrestrial and marine environments </li></ul><ul><li>They are everywhere! </li></ul>
What are Foraminifera ? <ul><li>Foraminifera are a group of Protozoa that are exclusively marine </li></ul><ul><li>There are pelagic and benthic Foraminifera </li></ul><ul><li>They occur everywhere in the oceans </li></ul><ul><li>Forams are particularly abundant in low temperature environments – e.g. the deep sea and polar seas – they appear to be the most common group of protozoa in Antarctic benthic environments! </li></ul>
There are different kinds of Forams… <ul><li>… some Forams are soft-bodied – they have an organic wall… </li></ul>
… agglutinated Foraminifera make their tests out of sediment particles…
… calcareous Foraminifera have shells made from calcium carbonate…
Investigates the impact of food input on the benthic environment and the organisms living on the Western Antarctic Peninsula shelf. FOODBANCS: Food for the B enthos on the An tarctic C ontinental S helf PIs Craig Smith, UH and Dave DeMaster, NCSU 1999-2000
<ul><li>Foraminifera show a strong specific response to pulsed food input </li></ul><ul><li>They are able to ingest a large part of freshly deposited organic matter quickly </li></ul><ul><li>Forams respond directly to food availability - other groups, e.g. nematode or polychaete worms, show a delayed response or no response at all. </li></ul>Why Forams?
What’s special about Forams? <ul><li>Being Protozoa, they can reproduce much faster than metazoa (asexual multiple fission) </li></ul><ul><li>A solid calcareous or agglutinated test provides protection against environmental factors and (arguably) predators </li></ul><ul><li>Forams have a high potential turnover rate - they can ‘burn’ a high amount of organic matter in a short period of time </li></ul><ul><li>Their reticulopodial net is a highly efficient food gathering apparatus (conveyor-belt movement) </li></ul>
FOODBANCS: Abundances of Foraminifera in the >300 m size class <ul><li>Agglutinated foraminifera are more abundant than metazoa in the macrobenthic size class (>300 m) in the topmost sediment layer (0-0.5 cm) </li></ul><ul><li>Metazoan organisms are more abundant in the 0.5-1.0 cm layer below </li></ul><ul><li>Organic matter from the spring phytoplankton bloom is most likely be processed to a great extent by foraminifera before metazoan organisms can get to it </li></ul>
Food that’s good for you (and other critters): Polyunsaturated Fatty Acids (PUFAs) <ul><li>PUFAs are a group of fatty acids – components of fats and oils – which are only produced by a small number of organisms, but needed by many </li></ul><ul><li>In the marine environment, photosynthetic organisms such as diatoms and flagellates produce PUFAs in high amounts </li></ul>
What are PUFAs good for? <ul><li>PUFAs are important for certain cell membrane properties, e.g. preservation of membrane fluidity under high pressure or low temperature (deep-sea, Antarctic!!) </li></ul><ul><li>Certain fish species need PUFAs in neural tissue (retinas and brain) </li></ul><ul><li>PUFAs are precursors for a number of animal hormones </li></ul><ul><li>Phytoplankton with high PUFA content supports higher zooplankton biomass – the availability of PUFAs is a limiting factor </li></ul>
FOODBANCS: results from lipid analysis <ul><li>Three of the most abundant species of Foraminifera feed very selectively on certain components of freshly deposited organic matter </li></ul><ul><li>There is some indication that certain species ingest and decompose that part of the phytodetritus which is rich in PUFAs and thus make it unavailable for other organisms </li></ul>
Objectives at Palmer <ul><li>Time series: development of fatty acid profiles of an abundant calcareous foraminiferal species – Globocassidulina crassa - in January-February </li></ul><ul><li>Feeding experiments on G. crassa – decomposition of the ‘high quality’ part of phytoplankton? </li></ul><ul><li>Suhr & Pond (2006) Deep Sea Research Part II, Volume 53, Issues 8-10 </li></ul>
So… <ul><li>Foraminifera have a potentially very important and complex role in areas with a pulsed food input such as the Antarctic. </li></ul>