Primary Production – One Ten East Log

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

The sun is shining, the nets are being pulled in and out and life is good aboard RV Investigator. – Captain Micheline Jenner 

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Notes: Cooling breezy trade winds and white caps on the ocean today!

Primary Production

By David Antoine

Every year in the contemporary ocean, phytoplankton use energy from the sun to take up carbon, nutrients and trace elements, and to transform it into a staggering amount of about 50 billion tons of organic matter. This is referred to as the oceanic net primary production (NPP), and is equivalent to the annual production of terrestrial plant ecosystems. NPP is commonly expressed in grams of carbon fixed per unit time and ocean surface area, e.g., a daily production in grams of Carbon per square metre. Oceanic NPP is thus a major component of the global carbon cycle, because part of the carbon taken up by phytoplankton is balanced by a flux of carbon dioxide (CO₂) from the atmosphere to the ocean. This, combined with the transfer of organic matter (carbon) towards the deep ocean, make up what is referred to as the oceanic biological pump of carbon.

Dr Charlotte Robinson (Curtin University) uses an AC-S spectrophotometer to determine primary production in the continuous flow-through seawater from a sub-surface intake on the RV Investigator. Photo: Micheline Jenner AM.

On the RV Investigator voyage primary production of phytoplankton from different depths of the ocean is being measured using incubations with radioactive Carbon¹⁴ in a photosynthetron. These estimates of primary production will be compared with those determined during the first International Indian Ocean Expedition 60 years ago.

Dr Charlotte Robinson (Curtin University) in the modular Isotope Container aboard the RV Investigator, conducting primary production studies with the photosynthetron at different light levels. Photo: Micheline Jenner AM.

Be sure to follow the daily posts of our One Ten East Logs from the IN2019_V03 aboard RV Investigator at https://iioe-2.incois.gov.in and www.wamsi.org.au.

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Another wonderful day had aboard RV Investigator with stunning calm conditions across the day and an amazing sunset.

– Captain Micheline Jenner

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Dilution Experiments

By Michael Landry

Phytoplankton can go through one or two generations (cell divisions) per day and are often eaten almost as fast as they divide, by protozoan grazers.

Because the size ranges of phytoplankton and microzooplankton broadly overlap, they cannot be mechanically separated from one another to determine these two different rates.

We do, however, have a technique for this, which involves dilution of the grazing impact. This entails changing the encounter frequency of predators and prey using filtered water with the same chemistry, from the same depth.

We create two conditions­–one with natural concentrations of predators and prey and the other in which the grazing has been slowed by about 2/3rds. From the differences in the measured rates of increase of phytoplankton of the two treatments, we can solve the equations for the two unknown rates. 

We run our experiments in a seawater-cooled, shipboard incubator system that has 6 light levels simulating the conditions of underwater light at the six depths where we collected our samples from the CTD.

The change in phytoplankton concentration in each bottle is measured by chlorophyll and by flow cytometry analyses of dominant populations.

After a lot of filtering, analyses and calculations, we will have a pretty good idea of how much of phytoplankton productivity is consumed by microzooplankton each day, how that varies with depth in the euphotic zone, and if there are significant differences among the stations or regions that we are sampling along the 110°East line.

Prof Michael Landry (Scripps Institution of Oceanography, USA) and Prof Raleigh Hood (University of Maryland Center for Environmental Science) filtering water from the CTD in preparation for Prof Landry’s world-renowned dilution experiments, which are conducted on the aft deck of RV Investigator. Photo: Micheline Jenner AM.

Simulating different light levels experienced at six different depths in the ocean, these seawater-cooled incubation tanks allow the calculation of phytoplankton growth and microzooplankton grazing rates. Photo: Micheline Jenner AM.

Each incubation box contains two bottles, one with the natural conditions of predators and prey and the other where the grazing conditions have been reduced or diluted. Photo: Micheline Jenner AM.

Prof Raleigh Hood (University of Maryland Center for Environmental Science) and Claire Davies (IMOS/CSIRO) tending to the dilution experiments on the aft deck of the RV Investigator. Here they are removing the bottles that have incubated for 24 hours. Photo: Micheline Jenner AM.

Be sure to follow the daily posts of our One Ten East Logs from the IN2019_V03 aboard RV Investigator at https://iioe-2.incois.gov.in and www.wamsi.org.au .

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Curt and I were listening to an Antarctic minke whale for most of the morning and sure enough it came past the vessel. These are often curious whales, so we were optimistically expectant, that the loud caller might come by. A crew member on deck spied it and alerted us! Alas, we had had our heads in a spreadsheet to share our data. It was a fleeting but lovely visit, enough to confirm the caller we heard was indeed  an Antarctic minke whale, yeah! – Captain Micheline Jenner

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Cytometry in the Micro-CSI Lab

By Martina Doblin

The Microbial Cell Sorting and Imaging or Micro-CSI is a mobile laboratory belonging to the University of Technology Sydney (UTS) is being used on board RV Investigator. On this voyage, the Micro-CSI houses a state-of-the-art flow cytometer, which uses laser light to analyse living cells and sort them from other particles in seawater. Cells (ranging in size from 0.5 to 50 microns) can be sorted and counted based on characteristics such as their relative size, internal complexity and fluorescence properties, varying upon the identity and physiological status of each cell. Cells of the same species will share common attributes such as the number and type of cellular membranes, organelles and pigments and are therefore visualised as cells that cluster tightly in the graphical output.

Peta Vine (PhD student University of Technology Sydney) at left and Camille Grimaldi (PhD student University of Western Australia) at right, stand outside the Micro-CSI mobile laboratory that has been loaded aboard the RV Investigator. Photo: Micheline Jenner AM.

Using the flow cytometer, we are determining the distribution of phytoplankton populations collected at various locations along the 110⁰ East transect. We are also isolating cells capable of photosynthesis (those containing pigments such as chlorophyll) and preserving them for future on-shore analysis. This information will be used to help estimate the primary productivity of marine phytoplankton, which represents the potential for nutrients and energy to be transferred to upper levels of the food web.

Inside the Micro-CSI laboratory, Camille Grimaldi (PhD student UWA) operates the state-of-the-art BD-Influx cell sorter. A water sample from the CTD is placed in a glass tube, and is analysed using lasers to provide detailed information regarding phytoplankton distribution and abundance along the 110°East meridian. Photo: Micheline Jenner AM.

Camille Grimaldi (PhD student University of Western Australia) collects water from the CTD that is analysed using the flow-cytometer in the Micro-CSI laboratory. Photo: Micheline Jenner AM.

Be sure to follow the daily posts of our One Ten East Logs from the IN2019_V03 aboard RV Investigator at https://iioe-2.incois.gov.in and www.wamsi.org.au.

A new report into Australia’s remote Kimberley region could hold the key to answering global questions about how some ecosystems survive under extreme environmental conditions.

The report, “Strategic Integrated Marine Science for the Kimberley Region”, released today by the Minister for Science Hon. Dave Kelly MLA, is the culmination of five years of research by 200 scientists from 25 organisations working on 23 projects to understand the marine biodiversity and ecology at regional and local scales.

The information has been produced for the Department of Biodiversity, Conservation and Attractions (DBCA) to support decision making and operational activities for the region and the Greater Kimberly Marine Park network managed by DBCA jointly with Traditional Owners. 

ABOVE: (L-R) Yawuru marine ranger Anthony Richardson, Minister for Science Hon. Dave Kelly MLA and DBCA Marine Park Coordinator Chris Nutt release the WAMSI Kimberley Marine Research Program Report in Broome

The program, managed by the Western Australian Marine Science Institution (WAMSI) collaboration of scientists from state, federal, industry and academic institutions, is one of the most comprehensive assessments of Australia’s North West.

WAMSI Science Program Leader Dr Kelly Waples (DBCA) said the report provides valuable information that can be used to predict and manage the likely changes in the future. 

“How the Kimberley environment changes over time will be determined by the interaction of economic, ecological and social processes, climate change, human population dynamics and industry,” Dr Waples said. “By understanding how the environment has changed and the ecosystem has adapted over the past 100 years to what it is today, we can better predict the likely response to current and future pressures and how we might mitigate any impacts.” 

This physically complex inshore environment supports a diverse range of habitats that include seagrasses and coral reefs, extensive intertidal mudflats and sponge-dominated filter-feeding communities with high levels of biological diversity. The region also supports large and iconic marine fauna including whales, dolphins, dugongs, turtles and estuarine crocodiles.

While aboriginal people have lived in the Kimberley for millennia and retain strong cultural connections to their saltwater country, this coastal and marine environment increasingly supports other activities such as tourism, commercial and recreational fishing, pearling, aquaculture and major port facilities associated with resource industries.

Despite the growth in activity, the research found that anthropogenic impacts remain low compared with other parts of the Western Australian coast and disturbance to much of the Kimberley marine environment is considered to be minor.

However, the study highlights the region is likely to be increasingly affected by a number of pressures including: climate change-related impacts such as coral bleaching; regional development and growth; and increased human access and use.

The $30 million Kimberley Marine Research Program was funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Link to Minister for Science Hon. Dave Kelly MLA media statement

Kimberley Marine Research Program

One Ten East Logs from the IIOE-2 voyage aboard RV Investigator will be posted on the WAMSI website during the month long voyage.

Another wonderful day had aboard RV Investigator with stunning calm conditions across the day and an amazing sunset.
– Captain Micheline Jenner

Log from One Ten East

The RV Investigator is currently undertaking oceanographic research along the 110°E meridian off Western Australia as part of the second International Indian Ocean Expedition. The voyage is led by Professor Lynnath Beckley of Murdoch University and the research is supported by a grant of sea time on RV Investigator from the CSIRO Marine National Facility.

Notes: Beautiful sunny weather, warm seas and lots of tropical flying fish.

Dilution Experiments

By Michael Landry

Phytoplankton can go through one or two generations (cell divisions) per day and are often eaten almost as fast as they divide, by protozoan grazers.

Because the size ranges of phytoplankton and microzooplankton broadly overlap, they cannot be mechanically separated from one another to determine these two different rates.

We do, however, have a technique for this, which involves dilution of the grazing impact. This entails changing the encounter frequency of predators and prey using filtered water with the same chemistry, from the same depth.

We create two conditions­–one with natural concentrations of predators and prey and the other in which the grazing has been slowed by about 2/3rds. From the differences in the measured rates of increase of phytoplankton of the two treatments, we can solve the equations for the two unknown rates.

We run our experiments in a seawater-cooled, shipboard incubator system that has 6 light levels simulating the conditions of underwater light at the six depths where we collected our samples from the CTD.

The change in phytoplankton concentration in each bottle is measured by chlorophyll and by flow cytometry analyses of dominant populations.

After a lot of filtering, analyses and calculations, we will have a pretty good idea of how much of phytoplankton productivity is consumed by microzooplankton each day, how that varies with depth in the euphotic zone, and if there are significant differences among the stations or regions that we are sampling along the 110°East line.

Prof Michael Landry (Scripps Institution of Oceanography, USA) and Prof Raleigh Hood (University of Maryland Center for Environmental Science) filtering water from the CTD in preparation for Prof Landry’s world-renowned dilution experiments, which are conducted on the aft deck of RV Investigator. Photo: Micheline Jenner AM.

Simulating different light levels experienced at six different depths in the ocean, these seawater-cooled incubation tanks allow the calculation of phytoplankton growth and microzooplankton grazing rates. Photo: Micheline Jenner AM.

Each incubation box contains two bottles, one with the natural conditions of predators and prey and the other where the grazing conditions have been reduced or diluted. Photo: Micheline Jenner AM.

Prof Raleigh Hood (University of Maryland Center for Environmental Science) and Claire Davies (IMOS/CSIRO) tending to the dilution experiments on the aft deck of the RV Investigator. Here they are removing the bottles that have incubated for 24 hours. Photo: Micheline Jenner AM.

Be sure to follow the daily posts of our One Ten East Logs from the IN2019_V03 aboard RV Investigator at https://iioe-2.incois.gov.in and www.wamsi.org.au .