Hvileæg af planktoniske copepoder i Isefjords sediment: Resting eggs by planktonic copepods in the Isefjord sediment

Adam Brandt Overbye, Birgitte Nilsson Bergholt, Frederik Larsen, Simon Jørgensen & Tina Jensen

Studenteropgave: Semesterprojekt

Abstrakt

This project is build around an experiment that aims to show if some copepods species in the Isefjord produce resting eggs. To examine if there are produced resting eggs in the Isefjord, 12 sediment samples were taken at four different locations in the Isefjord. The theory is that by cutting these sediment pillars in to smaller slices and placing these slices under suitable conditions, it should by observations every third day during a period of fifteen days – a total of five observations – be possible to count the number of hatched copepod larvae. From these numbers and from knowledge about the age of the sediment layers it is possible to make an assumption that the eggs are the same age as the sediment and therefore resting eggs. The present study focuses on the two kinds of resting eggs: Quiescent and diapause eggs. After fifteen days, and the total count up, its was evaluated that the experiment, despite some sources of error, showed that resting eggs can be found in the Isefjord, because of findings of hatched copepod larvae in many of the deeper layers of the pillars. Dette projekt omhandler et eksperiment, der skal vise, om visse vandloppearter i Isefjord producerer hvileæg. For at undersøge om der bliver lagt hvileæg i Isefjord, blev der taget 12 sedimentprøver fra fire forskellige lokaliteter i Isefjord. Teorien er, at ved at skære disse sedimentsøjler i mindre skiver og placere disse skiver under gunstige forhold, vil det ved observationer hver tredje dag, gennem en periode på i alt femten dage – i alt fem observationer – være muligt at tælle antallet af klækkede vandloppelarver. Ud fra disse tal, og fra en viden om alderen på sedimentlagene, er det muligt at lave en antagelse om, at æggene er af den samme alder som sedimentet, og derved om de er hvileæg. I rapporten fokuseres på de to slags hvileæg: Quiescente og diapauseæg. Efter femten dage og endt optælling blev det vurderet at forsøget, på trods af visse fejlkilder, gav et billede af, at hvileæg kan findes i Isefjord, da der i mange af de dybere lag i søjlerne blev fundet klækkede vandloppelarver.

UddannelserBasis - Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Basis
SprogDansk
Udgivelsesdato18 jun. 2007
VejledereBenni Winding Hansen

Emneord

  • Copepod
  • diapause
  • Isefjord
  • hvileæg