An Integrated Micro-Device System for Coral Growth and Monitoring

Summary

This protocol describes the development of a modular controllable micro-device system that can be applied for the long-term culturing and monitoring of sea corals.

Abstract

Corals are fundamental organisms in marine and coastal ecosystems. With the advancement of coral protection research in recent years, precise control of the coral culture environment is highly in demand for coral conservation and study. Here, we developed a semi-closed coral culture micro-device system as a multi-functional platform, which can provide accurate and programmable temperature control, a sterile initial environment, long-term stable water quality, an adjustable dissolved oxygen concentration, and a customized light spectrum for corals. Owing to the modular design, the coral culture system can be upgraded or modified by installing desirable new modules or removing existing ones. Currently, under appropriate conditions and with proper system maintenance, the sample corals can survive for at least 30 days in a healthy state. Furthermore, due to the controllable and sterile initial environment, this coral culture system can support research into the symbiotic relationship between corals and associated microorganisms. Therefore, this micro-device system can be applied to monitor and investigate sea corals in a relatively quantitative manner.

Introduction

The deterioration of coral reef ecosystems has been occurring worldwide over the past 70 years. Considering all the major coral areas across Central America¹, Southeast Asia^2,3,4,5,6, Australia^7,8, and East Africa⁹, the global coverage of coral reefs has halved since the 1950s¹⁰. This mass loss of coral reefs has resulted in ecological and economic problems....

Protocol

The corals used for the present study were Seriatopora caliendrum, which are cultured in our lab. All the corals were kindly provided by the South China Sea Institute of Oceanology, University of Chinese Academy of Sciences.

1. Inspection and startup

NOTE: Each module must be tested for tightness and function individually before assembling the system. Deionized water should be used to test the module's tightness. Commercial details of all the module components are provided in the Table of Materials.

1. Tightness test of the inter-module connection

Results

Temperature control accuracy
The system temperature is normally set to 23-28 °C depending on the coral species. However, as one of the most important factors, temperature fluctuation can strongly affect coral survival. Hence, temperature control accuracy is a decisive factor for the coral culture system. A temperature sensor and an independent data collector with a temperature range from 9 °C to 32 °C can be used to test the temperature control accuracy in the coral culture module. We set the system .......

Discussion

This coral culture system is designed to simulate and provide a relatively natural or customized microenvironment for corals to be transplanted into and survive. Meanwhile, as a self-developed equipment, this system needs to be reliable, user-friendly, and safe. For example, in terms of temperature control, the seawater temperature should be controlled appropriately based on the daily environmental circumstances. The system was tested by culturing the coral for 1 month, confirming the system's reliability.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
12V DC power supply	Delixi Electric Co., Ltd.	CDKU-S150W	12V12.5A
3% hydrogen peroxide solution	Shandong ANNJET High tech Disinfection Technology Co., Ltd	NULL	NULL
75% ethanol solution	Shandong ANNJET High tech Disinfection Technology Co., Ltd	NULL	NULL
Air pump	Chongyoujia Supply Chain Management Co., Ltd.	NHY-001	NULL
Air sterilizing filter	Beijing Capsid Filter Equipment Co., Ltd	S593CSFTR-0.2H83SH83SN8-A	NULL
Camera	SONY	Α7r4-ILCE-76M4A	NULL
Coral nutrition solution	Red Sea Aquatics Co., Ltd.	22101	Coral nutrition
Coral pro salt (sea salt)	Red Sea Aquatics Co., Ltd.	R11231	NULL
Cycle timer	Leqing Shangjin Instrument Equipment Co., Ltd.	CN102A	220V version
Double closed quick connector	JOSOT Co., Ltd	NL4-2103T	NULL
Flow-through UV lamp	Zhongshan Xinsheng Electronic technology Co., Ltd.	211	NULL
Four-channel transformer	Dongguan Shanggushidai Electronic Technology Co., Ltd	LM2596	NULL
Macro lens	SONY	FE 90mm F2.8 Macro G OSS	NULL
Microbiome source solution	Guangzhou BIOZYM Microbial Technology Co., Ltd.	303	NULL
Mini-photo studio	Shaoxing Shangyu Photography Equipment Factory	CM-45	NULL
PID temperature controller	Guangdong Dongqi  Electric Co., Ltd.	TE9-SC18W	SSR version
Pump (for water)	Zhongxiang Pump Co., Ltd.	ZX43D	Seaswater version
Pure water machine	Kemflo (Nanjing) environmental technology Co, ltd	kemflo A600	NULL
Solid-state relay	Delixi Electric Co., Ltd.	DD25A	NULL
Surface active agents	Guangzhou Liby Group Co., Ltd.	Libai detergent	NULL
Three-channel timer	Leqing Changhong Intelligent Technology Co., Ltd.	CHE325-3	220V version
Water sterilizing filter	Beijing Capsid Filter Equipment Co., Ltd	S593CSFTR-0.2H83SH83SN8-L	NULL