Continuous Zooplankton Monitoring (Maldives)
Mixed sample of Zooplankton specimens ready for individual ID
Introduction to Plankton
Plankton is vital to human survival. Forming the first two levels of the marine food web, plankton essentially keeps the oceans alive and us along with it. Phytoplankton (the plant category of plankton) is also responsible for as much as 80% of the air we breathe!
Here at Marine Savers at Four Seasons Resorts Maldives, we have just started our own journey into plankton studies, with a focus on zooplankton. This is the animal side of plankton, and arguably the most interesting! A study of this size and time frame has not been seen in the Maldives before, and it is the first continuous plankton study of its kind in a UNESCO Biosphere Reserve.
Zooplankton feeds the world’s largest animal, the blue whale, as well as Baa Atoll’s charismatic megafauna that put it on the map – manta rays (for more details, refer to The Manta Trust: Mobulid Behavioural Ecology – and – Crittercam Reveals Manta Ray Feeding Secrets.)
Our continuous study is to collect baseline data on zooplankton communities around Baa atoll, with the hope to expand nationwide, providing ample opportunities for local and international organisations, communities, NGOs and students to collaborate and create their own research projects supported by our data. Not only will we be able to provide long-term datasets, but we will also be standing by to provide training, support and hopefully ID workshops, to ensure good quality data is collected from all sample sites.
Our method uses the reliably tried-and-tested plankton tow net. With the right calculations and additional equipment, we can determine sampled water volumes and start to create a detailed model of zooplankton densities and diversity in target areas, while monitoring for changes over time using the detailed continuous data in our custom-built database. Other possible areas of research can be extended to include pollution, micro-plastics, biomass, and even climate change.
We encourage any interested collaborators to contact us at Landaa Giraavaru, and see how we can work together to better understand the unseen and under-studied animal communities living in the oceans around us.
We are waiting for delivery of sampling equipment to start our new zooplankton study. We are kindly supported by the Marine Biological Association (MBA), who have been at the forefront of global oceanic plankton sampling for the last 60 years. We will continue to stay in contact with the MBA for future collaboration opportunities.
We have also been in discussions with the new resident Assistant Manager at the Manta Trust, who is interested in studying plankton in Hanifaaru bay for a PhD. We are confident that we can provide mutually beneficial data, methodologies and ID development in this new inter-agency collaboration (that we hope to grow and develop).
While we await the equipment delivery, we have created a simple database to use for data collection. We have also been collating a library of scientific papers on plankton (Indian Ocean, climate change, etc).
We held a video call with zooplankton expert, Anthony Richardson, (CSIRO Australia), discussing formalin concentrations (with safe handling/disposal), and the actual identification of the zooplankton (majority will be copepods). We plan to purchase:
- Flow meter (vital for getting volume measurements and adding validity to our data)
- Small oven (to determine biomass of samples, widening our scope of applications at a low upfront cost)
- Scientific weighing scales (to weigh dried samples)
This is a great opportunity to be the first long-standing plankton study in the Maldives, with potential for future growth and interaction both locally and globally.
While waiting for our final kit shipment to arrive (flow-meter, nets, microscope, scales) we have been restructuring the Fish Lab to better accommodate our new plankton research station (housing the dehydrator, splitter, and nets). With the kind assistance of the Resort engineering team, we have constructed our own Motodo splitter (saving $600+).
With valuable input from Hannah (Manta Trust), we have also drafted protocols for:
(1) the safe use of formalin, and
(2) plankton sampling.
These protocols will be reviewed by our kind mentors at:
– MBA [UK] (Dave Conway), and
– CSIRO [AUS] (Dr Anthony Richardson and Frank Coman).
We have a new Lab-made net (photo), to gain practise and refine methodology before the remainder of our equipment arrives (nets and pipettes). Thanks to our resort colleagues for all their invaluable help, including Engineering (custom metal ring) and Laundry (stitching).
During collection, we will experiment with different duration/speed/distance, to ensure a large enough sample without bursting the fine netting (150µm). We will practice using our Lab-made motodo splitter, and try sub-sampling with spring-loaded pipettes. We will also be practising: separation, rinsing and dehydration, storage (in formalin), and most importantly, actually identifying the zooplankton samples.
We have now received all of our zooplankton collection equipment, and have made some successful trials with our temporary homemade net.
- We have determined that a one-minute tow with the 150µm mesh net will provide a good quantity of zooplankton for analysis.
- Thorough cleaning of the flow meter is a time-consuming task, so we are exploring new methods. The flow meter allows us to determine speed, distance and volume, facilitating data entry without extra equipment.
- We will need a ‘spin checker’ to perform periodic calibration of the flow meter.
- We are experimenting with various apps to determine GPS coordinates for plot points on ‘Google Earth Pro’.
- The splitter and dehydration process are successful, but we need to fine-tune the measurements.
- Identifying the large number of zooplankton specimens will be time-consuming, although we do have both a stereo microscope (preferred) and a compound microscope.
- Hannah, a zooplankton expert, has recently arrived at Landaa, and will soon be commencing her study. We aim to collaborate as much as possible over the coming months to solidify a methodology that is replicable and can continue long into the future.
Our custom-built Motodo splitter
Our temporary hand-made 150µm plankton net
After consultation with the manufacturer, we will start to clean our flow meter with fresh water and vinegar after each use (no need for complete disassembly). We have ordered a ‘spin checker’ to ensure the flow meter is working correctly and accurately, eliminating the need for calibration tows.
The next challenge is to increase confidence and accuracy of our zooplankton identifications, so we have purchased a range of step-by-step ID guides from plankton experts.
For collection of our zooplankton samples, we have started to complete tows in specific areas (Parrot Reef, Nurafaru) with our collection nets. After initial data analysis, we plan to increase our standard tow-time to three minutes for a larger and more diverse sample.
We are currently training up to ID the various zooplankton, complete the streamlined recording sheet, and proceed with the necessary data entry process.
To collect our zooplankton specimens, we have started regular three-minute tows from scheduled boat excursions that are running smoothly. In fact, many guests show a keen interest during the sampling work, and subsequently come along to our Fish Lab for a hands-on microscopic viewing of the new zooplankton.
- The tows have provided useful baseline data, but our methodology still needs to be standardised.
- The actual zooplankton identifications are becoming easier with practise.
- Our count-sheet and database have been streamlined.
- We have shifted to the Beaufort Scale to record weather conditions.
- Polygons on Google Earth Pro have been created to highlight our target sampling sites.
- We hope to collaborate with the Manta Trust team, who are planning their own surveys at more remote sites used for manta feeding.
- We plan to use vials for preserving some samples for archiving and for possible future analysis.
Porcelain crab larvae