An Ultra-clean Multilayer Apparatus for Collecting Size Fractionated Marine Plankton and Suspended Particles

Summary

Plankton and suspended particles play a major role in the biogeochemical cycles in the ocean. Here, we provide an ultra-clean, low stress method for the collection of various sizes of particles and plankton at sea with the capability of handling large volumes of seawater.

Abstract

The distributions of many trace elements in the ocean are strongly associated with the growth, death, and re-mineralization of marine plankton and those of suspended/sinking particles. Here, we present an all plastic (Polypropylene and Polycarbonate), multi-layer filtration system for collection of suspended particulate matter (SPM) at sea. This ultra-clean sampling device has been designed and developed specifically for trace element studies. Meticulous selection of all non-metallic materials and utilization of an in-line flow-through procedure minimizes any possible metal contamination during sampling. This system has been successfully tested and tweaked for determining trace metals (e.g., Fe, Al, Mn, Cd, Cu, Ni) on particles of varying size in coastal and open ocean waters. Results from the South China Sea at the South East Asia Time-Series (SEATS) station indicate that diurnal variations and spatial distribution of plankton in the euphotic zone can be easily resolved and recognized. Chemical analysis of size-fractionated particles in surface waters of the Taiwan Strait suggests that the larger particles (>153 µm) were mostly biologically derived, while the smaller particles (10 - 63 µm) were mostly composed of inorganic matter. Apart from Cd, the concentrations of metals (Fe, Al, Mn, Cu, Ni) decreased with increasing size.

Introduction

Particles in the ocean play an important role in marine biogeochemical cycles¹. Most of the properties of particles, such as size, mineralogy, and composition, can change profoundly from one geological or hydrographical setting to another². In addition, the distributions of elements in the ocean are also associated with the life cycle of marine phytoplankton: growth, death, sinking, and re-mineralization^3,4. Marine particles span at least 4 orders of magnitude in size, ranging from submicron particles to large aggregates (>5 mm). Most particles are biological....

Protocol

The following protocol involves working with harmful chemicals. Please read the Safety Data Sheets (SDS) carefully, and follow institutional chemical safety guidelines.

1. Multi-layer Gravity Filtration Sampler Preparation

1. Sampler cleaning
   1. Fill the tubing and filtration unit with 1% (w/v) of anionic protease enzyme detergent solution and soak it for 24 h. Flush the multi-layer gravity filtration sampler with reverse osmosis double distilled water (RO-DDW) thoroughly, then fill it with 0.1% (v/v) hydrochloric acid (HCl, Reagent Grade) and soak for 72 h.
   2. Thoroughly flush the multi-layer grav....

Results

With the development of modern oceanography, it is now a common practice to use "clean techniques" to obtain accurate trace metal concentrations in marine particles or plankton. Since most particles in natural waters are in the low mg/L to µg/L range, the treatment of large volumes of seawater is necessary to investigate geochemical and biological effects of trace metals on various particles in ambient environments. With the use of clean, multi-layer gravity filtration ("CATNET") sampling.......

Discussion

Obtaining reliable trace metal concentrations on plankton and suspended particles in natural waters, which are generally present at very low concentrations, requires great care during sample collection, processing, pretreatments, and analysis, with the aim of reducing contamination. Therefore, the procedures to design and prepare sampling gear, sample containers, and materials used to collect and process samples are all critical steps toward obtaining high-quality data for trace metals in marine environments. With the ad.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
thermoplastic elastomer (C-Flex) Tubings	Cole Palmer	EW-06424-67	O.D. 0.635 cm, Opaque White 1/8"ID x 1/4"OD, 25 ft/pack
LDPE Bottle (Nalgene)	ThermoFisher Scientific	2103-0004	125 mL, Nalgene Wide-Mouth LDPE Bottles with Closure
anionic protease enzyme detergent detergent (Tergazyme)	Alconox	1104-1	1×4 lb box (1.8 kg)
Hydrochloric Acid	Sigma-Aldrich	258148	Reagent grade
Nitric acid	Sigma-Aldrich	695025	Reagent grade
alkaline detergnet (Micro)	Cole Palmer	EW-99999-14	Micro-90 Cleaning Solution
polycarbonate filter, 47 mm, 0.4 µm	Sigma-Aldrich	WHA111107	Whatman Nuclepore Track-Etched Membranes, diam. 47 mm, pore size 0.4 μm, polycarbonate
polycarbonate filter, 47 mm, 10 µm	Sigma-Aldrich	WHA111115	Whatman Nuclepore Track-Etched Membranes, diam. 47 mm, pore size 10 μm, polycarbonate
PFA vessel, 60 ml capacity	Savillex	300-060-03	60 mL Digestion Vessel, Flat Interior, Flat Exterior, Buttress Threaded Top
Nitric acid, ultrapure	Seastar Chemicals	N/A	BASELINE Nitric Acid
HF, ultrapure	Seastar Chemicals	N/A	BASELINE Hydrofluoric Acid
Boric acid, ultrapure	Seastar Chemicals	N/A	BASELINE Hydrobromic Acid
polyethylene (PE) gloves	Safty Zone	GDPL-MD-5	Clear Powder Free Polyethylene Gloves
Multiple layer filtering and collecting device	Sino Instrumnets Co. Ltd	not available	Multiple layer filtering and collecting device, CATNET
10 um Nylon filters, Nitex	Dynamic Aqua-Supply Ltd.	NTX 10	Nitex - Standard Widths (40 - 44 inches)
60 um Nylon filters, Nitex	Dynamic Aqua-Supply Ltd.	NTX 60	Nitex - Standard Widths (40 - 44 inches)
150 um Nylon filters, Nitex	Dynamic Aqua-Supply Ltd.	NTX 150	Nitex - Standard Widths (40 - 44 inches)
torque wrench	Halfords	200238	Halfords Professional Torque Wrench 8-60Nm
multi-bottle sampling array, Rosette	General Oceanics	Model 1018	Rosette Sampler
PTFE-coated sampling bottles, GO-Flo	General Oceanics	108020T	GO-Flo water sampler teflon coated
Marine sediment reference materials	National Research Council Canada	MESS-3
Estuarine sediment standard reference material	National Institute of Standards and Technology	1646a
Plankton reference material	The European Commission's science and knowledge service	CRM414