Transparent Marine Animals – 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.

 

 

 

 

 

 

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.

 

Date: May 22, 2019	Time:  1200 AWST
Latitude: 32°S	Longitude: 110°E
Wind direction: WSW	Wind speed: 3 knots
Swell direction: SW	Depth: 5163 m
Air temperature: 17°C	Sea temperature: 19.5°C
Notes: What a beautiful day! The samples are full of rock lobster larvae (phyllosoma) and two pygmy blue whales are belting out low frequency calls. Are they looking for a dinner date?

 

Transparent Marine Animals

By Andrew Jeffs

Living in the clear waters of the open ocean is a dangerous business when you are a small swimming organism because there is nowhere to hide from predators. However, many marine creatures have evolved a clever way to overcome the lack of hiding places. They have evolved to make their bodies transparent–so they are almost invisible in the seawater. Having a transparent body can also be handy if you are a predator, as it helps for sneaking up on your prey unseen. Many different types of open ocean organisms have evolved to become transparent including fish, crustaceans, worms, jellyfish and squid. In fact, in some areas of the open ocean, over 90% of the organisms larger than a full stop, are transparent. Despite the prevalence of this phenomenon, it is not well known how these organisms achieve transparency, particularly requiring body tissues that do not absorb or bend light. Whilst on board the RV Investigator in the Indian Ocean we are capturing different types of small transparent ocean organisms in nets and then using laser beams to measure how well their bodies match the optical properties of the surrounding seawater, in order to achieve transparency.

 

Prof Andrew Jeffs (University of Auckland) shines a light on a plankton sample collected from the RV Investigator, while Daniel Cohen (Murdoch University Honours student) selects a transparent rock lobster larva for further examination.

 

A transparent rock lobster phyllosoma larva, which drift in the open ocean for nearly a year before metamorphosing and settling near the coast. Photo: Prof Lynnath Beckley.

 

Overall, from the range of nets we are using (and a lot of microscope work), we can quantify zooplankton in the south-east Indian Ocean, process this information in food web analyses and include the data in models of ocean functioning.

Be sure to follow our daily Log from One Ten East at https://iioe-2.incois.gov.in or 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.

 

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.

 

Date: May 21, 2019	Time:  1200 AWST
Latitude: 33.5°S	Longitude: 110°E
Wind direction: WSW	Wind speed: 12 knots
Swell direction: WSW	Depth: 2644 m
Air temperature: 15.2°C	Sea temperature: 18.2 °C
Notes: The wind is calming and the sky clearing as RV Investigator traverses the Naturaliste Plateau. The scientists are happy as the sample jars are being dutifully labelled and filled.

 

Net Benefits

By Prof Lynnath Beckley

 

The word plankton is derived from the Greek word ‘planktos’ meaning drifter. Planktonic organisms generally drift in the ocean but some can undertake limited swimming to achieve vertical migration from the depths towards the surface to feed at night.

On our voyage with the RV Investigator, along the 110°E meridian in the south-east Indian Ocean, in addition to filtering very tiny organisms from water samples, we are using a wide variety of nets to capture plankton. These range from a tiny net with 20-micron mesh to catch phytoplankton to a large net with 1000-micron (=1 mm) mesh to catch larger zooplankton like krill, and the larvae of fish and rock lobsters.

One of the most historically significant nets we are using is the Indian Ocean Standard Net. We have a specially built replica of the original nets deployed by 14 different ships during the first Indian Ocean Expedition in the 1960s to compare the biomass (weight) of zooplankton in the surface 200m of the water column across the ocean basin. We are replicating these vertical hauls at the same time of the year and locations along the 110°E meridian to ascertain if there are any major differences in the biomass and composition of the zooplankton between the two voyages.

The Indian Ocean Standard Net (IOSN) is the one of the original nets used in the International Indian Ocean Expedition. This one used on the IIOE-2 is a replica allowing for interesting comparisons across the 60 years or so since the first voyage. Photo: Micheline Jenner.

 

Dr David Tranter, formerly of CSIRO, and now well-retired, led the Australian plankton research during the first expedition and was responsible for numerous publications revealing the composition and abundance of zooplankton in the south-east Indian Ocean. He and his wife, Helen, even went to live in India for a while to train scientists at the Indian Ocean Biological Centre to process and identify the over 2000 zooplankton samples that were collected by nine countries during the first expedition.

 

Dr David Tranter and Prof Lynnath Beckley comparing notes on Indian Ocean zooplankton prior to the 2019 voyage. Photo: Dr Tony Miskiewicz.

 

Other equipment that is particularly useful for elucidating plankton is the EZ multiple opening and closing net. This consists of ten 500-micron nets in a big frame and they are electronically opened and closed at different depths in the ocean to sample the zooplankton. This enables comparison of the depths that various zooplankton reside during the day and night and allows us to quantify zooplankton abundance in different depth zones.

 

The EZ net being deployed from the A-frame of RV Investigator on the aft deck by the experienced deck crew. The EZ net comprises a rectangular frame holding ten nets, each of which are closed remotely at various depths. Photo: Micheline Jenner.

 

 

 

Opening and closing the EZ net at different depth strata are Ian McRobert, Prof Lynnath Beckley (Murdoch University) and Pilar Olivar (IMS, Barcelona) in the Operations Room on board RV Investigator. Photo: Micheline Jenner.

 

 

The camera view looking into the EZ net shows the mechanism for obtaining fishes from different strata. In the centre of the image, the “bar” across the centre is one of the frames of one of the nets. Photo: Micheline Jenner.

 

Overall, from the range of nets we are using (and a lot of microscope work), we can quantify zooplankton in the south-east Indian Ocean, process this information in food web analyses and include the data in models of ocean functioning.

 

Be sure to follow our daily Log from One Ten East at https://iioe-2.incois.gov.in or 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.

We had a couple of fronts blow through today, but the 27-30 knots of wind and blustery rain did not hinder the wonderful work of the deck crew. All the nets were deployed and retrieved carefully and efficiently. 

There is blue sky ahead but even in the slightly blustery conditions, the company of Wandering and Black-browed Albatross at Station 3 was appreciated.

 

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.

Date: May 20, 2019	Time:  1200 AWST
Latitude: 35°S	Longitude: 110°E
Wind direction: WSW	Wind speed: 23 knots
Swell direction: W	Depth: 4911 m
Air temperature: 14.8°C	Sea temperature: 18.3°C
Notes: The rain has cleared and there are patches of blue sky all around! Rock lobster larvae (phyllosoma) were caught in the surface nets last night and pygmy blue whales were heard calling in the east.

 

Micro- and Mesozooplankton

By Michael Landry

Planktonic consumers can be divided into two major size classes, the micro- and mesozooplankton, depending on whether they pass through or are retained on 200-µm mesh sieve. The mesozooplankton consists mainly of true multicellular animals, like copepods, euphausiids (krill) and chaetognaths (arrow worms), that are concentrated and collected by towing a plankton net with 200-µm mesh through the water. In contrast, the microzooplankton (<200 µm) category contains mainly protozoans (single-cell flagellates and ciliates) with some very small animals and is best collected by preserving water samples without prior net concentration.

Schematic of an oceanic food web. Credit:  Steinberg & Landry (2017)

 

Both micro- and mesozooplankton are diverse assemblages of organisms with varying life strategies and feeding preferences, but they are associated with different functions in ocean food webs. Microzooplankton are typically the main consumers of phytoplankton and bacteria, especially in regions where the dominant phytoplankton Mesozooplankton, on the other hand, are the main food web link to higher level animals (fishes), and they are associated with mechanisms (daily migrations, rapidly sinking fecal pellets) that move organically fixed carbon and nutrients out of the euphotic zone and into deeper layers of the ocean. Studying how ocean systems differ in terms of how productivity moves through micro- versus mesozooplankton is therefore a basic approach to characterizing their different relative functions in nutrient recycling, trophic transfers and carbon export.

Prof Michael Landry (Scripps Institution of Oceanography and Sir Walter Murdoch Distinguished Collaborator), with his mesozooplankton net on the aft deck of RV Investigator. Note, the flowmeter which allows quantification of abundance of plankton per cubic metre of seawater. Photo: Micheline Jenner.

 

Claire Davies (IMOS/CSIRO) fractionates the plankton sample from the 200-µm net through a range of sieves to determine the abundance of different-sized organisms in the zooplankton. Photo: Micheline Jenner.

 

Prof Michael Landry (Scripps Institution of Oceanography) gently lifts a filter paper containing small mesozooplankton. Photo: Micheline Jenner.

 

After fractionation, the different-sized organisms in the plankton are revealed. From left to right, large zooplankton (e.g. chaetognath here) retained on a coarse mesh, through to copepods retained on the fine 200-µm mesh. Photo: Micheline Jenner.

 

Be sure to follow our daily Log from One Ten East at https://iioe-2.incois.gov.in or 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.

We have had another fantastic day in the Indian Ocean aboard RV Investigator. The CTD was deployed early in the morning and with a calm sea and light wind, the first station on the 110 East line was successfully completed. Micro and macro zooplankton have been collected with various nets, the CTD rosette was lowered twice and from those water samples, nutrients and microbes have been sampled for analysis.

We even had a minke whale sighted not too far from the ship and then two fin whales passed the starboard side and then across the bow! We have plankton and whales, life is good!

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.

 

Date: May 18, 2019	Time:  1200 AWST
Latitude: 38°S	Longitude: 110°E
Wind direction: N	Wind speed:  15 knots
Swell direction: SW	Depth:  4266 m
Air temperature: 13.7°C	Sea temperature: 13.8°C
Notes: Station 1 is done and dusted. It was a very busy day with lots of samples and data collected by many satisfied scientists.

 

Tiny Microbes, Big Impact

By Dr Martin Ostrowski

Microbes are everywhere, they’re in the soil, on our skin, in our guts and they live in the ocean in incredible numbers. In a similar role to our gut microbes, which are keeping us healthy, research has revealed that ocean microbes play important roles sustaining our planet. What are these microbes and what are they doing? Onboard RV Investigator a team of microbiologists is addressing these questions using modern molecular methods. They aim to identify which microbes are present and determine how they thrive and interact with other species. This work will help us understand how these tiny organisms support the production of food in the ocean, which feeds over 1 billion people, and ultimately plays a fundamental role keeping our planet healthy. 

Most marine microbes are planktonic, but surprisingly, they fundamentally shape their surroundings by transforming over 90% of all organic matter, driving major elemental and geochemical cycles, and making and breaking chemical compounds that have a direct effect on climate. What they lack in size, they make up for in sheer numbers.

The activity of microbes impacts on all levels of the marine systems, from water chemistry and primary production, which ultimately supports all marine life, through to regulating climate and playing a role in the health of the largest mammals on the planet. Over geological time, free-living marine microbes have been the main source of power for the planet. By modern estimates, approximately half of all primary production occurs in the oceans. In very general terms, this means that marine microbes are like the lungs of the planet, but in reverse, drawing in carbon dioxide and releasing oxygen for us to breathe.

 

In the CTD room, several scientists retrieve water samples from the Niskin bottles for microbial analyses. In the foreground from left, Amaranta Focardi (Macquarie University) documenting the details and James O’Brien (University of Technology Sydney) and Dr Peter Thompson (CSIRO) taking water from the rosette. Photo: Micheline Jenner.

 

Microbes are invisible to the naked eye, especially the single-celled species, which make up the bulk of ‘biomass’ in the oceans. Much of the work done in the microbiology lab involves flow cytometry and high-throughput genome sequencing of water samples collected from different depths using the CTD rosette of Niskin bottles. We use the cytometer to count different types of bacteria, cyanobacteria, micro algae and virus particles. There are more than one million microbial cells in each millilitre of seawater, and 10 times more viruses! Sequencing of microbial marker genes provides estimates of total diversity in the Australian marine microbiome.

 

 

Pramita Ranjit (Macquarie University) filters water in one of the laboratories on the RV Investigator to determine the microbiome of the south-east Indian Ocean at the first station on the 110° East line. Photo: Micheline Jenner.

 

Be sure to follow our daily Log from One Ten East at https://iioe-2.incois.gov.in or 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.

We had a couple of fronts blow through today, but the 27-30 knots of wind and blustery rain did not hinder the wonderful work of the deck crew. All the nets were deployed and retrieved carefully and efficiently. 

There is blue sky ahead but even in the slightly blustery conditions, the company of Wandering and Black-browed Albatross at Station 3 was appreciated.

 

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.

Date: May 20, 2019	Time:  1200 AWST
Latitude: 35°S	Longitude: 110°E
Wind direction: WSW	Wind speed: 23 knots
Swell direction: W	Depth: 4911 m
Air temperature: 14.8°C	Sea temperature: 18.3°C

Notes: The rain has cleared and there are patches of blue sky all around! Rock lobster larvae (phyllosoma) were caught in the surface nets last night and pygmy blue whales were heard calling in the east.

Micro- and Mesozooplankton

By Michael Landry

Planktonic consumers can be divided into two major size classes, the micro- and mesozooplankton, depending on whether they pass through or are retained on 200-µm mesh sieve. The mesozooplankton consists mainly of true multicellular animals, like copepods, euphausiids (krill) and chaetognaths (arrow worms), that are concentrated and collected by towing a plankton net with 200-µm mesh through the water. In contrast, the microzooplankton (<200 µm) category contains mainly protozoans (single-cell flagellates and ciliates) with some very small animals and is best collected by preserving water samples without prior net concentration.

Both micro- and mesozooplankton are diverse assemblages of organisms with varying life strategies and feeding preferences, but they are associated with different functions in ocean food webs. Microzooplankton are typically the main consumers of phytoplankton and bacteria, especially in regions where the dominant phytoplankton Mesozooplankton, on the other hand, are the main food web link to higher level animals (fishes), and they are associated with mechanisms (daily migrations, rapidly sinking fecal pellets) that move organically fixed carbon and nutrients out of the euphotic zone and into deeper layers of the ocean. Studying how ocean systems differ in terms of how productivity moves through micro- versus mesozooplankton is therefore a basic approach to characterizing their different relative functions in nutrient recycling, trophic transfers and carbon export.

Be sure to follow our daily Log from One Ten East at https://iioe-2.incois.gov.in or www.wamsi.org.au